Unleashed v1.4

[unleashed.git] / usr / src / cmd / sgs / elfedit / common / elfedit.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include        <sys/types.h>
#include        <sys/stat.h>
#include        <sys/wait.h>
#include        <stdarg.h>
#include        <fcntl.h>
#include        <stdlib.h>
#include        <stdio.h>
#include        <signal.h>
#include        <dirent.h>
#include        <libelf.h>
#include        <gelf.h>
#include        <conv.h>
#include        <dlfcn.h>
#include        <link.h>
#include        <stdarg.h>
#include        <libgen.h>
#include        <libintl.h>
#include        <locale.h>
#include        <unistd.h>
#include        <errno.h>
#include        <ctype.h>
#include        <limits.h>
#include        <strings.h>
#include        <sgs.h>
#include        "msg.h"
#include        "_elfedit.h"
#include        <debug.h>       /* liblddb */



/*
 * Column at which elfedit_format_command_usage() will wrap the
 * generated usage string if the wrap argument is True (1).
 */
#define USAGE_WRAP_COL 55




/*
 * Type used to represent a string buffer that can grow as needed
 * to hold strings of arbitrary length. The user should declare
 * variables of this type sa static. The strbuf_ensure_size() function
 * is used to ensure that it has a minimum desired size.
 */
typedef struct {
        char *buf;              /* String buffer */
        size_t n;               /* Size of buffer */
} STRBUF;




/*
 * Types used by tokenize_user_cmd() to represent the result of
 * spliting a user command into individual tokens.
 */
typedef struct {
        char    *tok_str;       /* Token string */
        size_t  tok_len;        /* strlen(str) */
        size_t  tok_line_off;   /* Token offset in original string */
} TOK_ELT;
typedef struct {
        size_t  tokst_cmd_len;  /* Length of original user command, without */
                                /*      newline or NULL termination chars */
        size_t  tokst_str_size; /* Space needed to hold all the resulting */
                                /*      tokens, including terminating NULL */
        TOK_ELT *tokst_buf;     /* The array of tokens */
        size_t  tokst_cnt;      /* # of tokens in array */
        size_t  tokst_bufsize;  /* capacity of array */
} TOK_STATE;




/* State block used by gettok_init() and gettok() */
typedef struct {
        const char      *gtok_buf;      /* Addr of buffer containing string */
        char            *gtok_cur_buf;  /* Addr withing buffer for next token */
        int             gtok_inc_null_final; /* True if final NULL token used */
        int             gtok_null_seen; /* True when NULL byte seen */
        TOK_ELT         gtok_last_token; /* Last token parsed */

} GETTOK_STATE;




/*
 * The elfedit_cpl_*() functions are used for command line completion.
 * Currently this uses the tecla library, but to allow for changing the
 * library used, we hide all tecla interfaces from our modules. Instead,
 * cmd_match_fcn() builds an ELFEDIT_CPL_STATE struct, and we pass the
 * address of that struct as an opaque handle to the modules. Since the
 * pointer is opaque, the contents of ELFEDIT_CPL_STATE are free to change
 * as necessary.
 */
typedef struct {
        WordCompletion  *ecpl_cpl;              /* tecla handle */
        const char      *ecpl_line;             /* raw input line */
        int             ecpl_word_start;        /* start offset within line */
        int             ecpl_word_end;          /* offset just past token */
        /*
         * ecpl_add_mod_colon is a secret handshake between
         * elfedit_cpl_command() and  elfedit_cpl_add_match(). It adds
         * ':' to end of matched modules.
         */
        int             ecpl_add_mod_colon;
        const char      *ecpl_token_str;        /* token being completed */
        size_t          ecpl_token_len;         /* strlen(ecpl_token_str) */
} ELFEDIT_CPL_STATE;




/* This structure maintains elfedit global state */
STATE_T state;



/*
 * Define a pair of static global variables that contain the
 * ISA strings that correspond to %i and %I tokens in module search
 * paths.
 *
 *      isa_i_str - The ISA string for the currently running program
 *      isa_I_str - For 64-bit programs, the same as isa_i_str. For
 *              32-bit programs, an empty string.
 */

#ifdef __i386
static const char *isa_i_str = MSG_ORIG(MSG_ISA_X86_32);
static const char *isa_I_str = MSG_ORIG(MSG_STR_EMPTY);
#endif
#ifdef __amd64
static const char *isa_i_str = MSG_ORIG(MSG_ISA_X86_64);
static const char *isa_I_str = MSG_ORIG(MSG_ISA_X86_64);
#endif



/* Forward declarations */
static void free_user_cmds(void);
static void elfedit_pager_cleanup(void);



/*
 * We supply this function for the msg module
 */
const char *
_elfedit_msg(Msg mid)
{
        return (gettext(MSG_ORIG(mid)));
}


/*
 * Copy at most min(cpsize, dstsize-1) bytes from src into dst,
 * truncating src if necessary.  The  result is always null-terminated.
 *
 * entry:
 *      dst - Destination buffer
 *      src - Source string
 *      dstsize - sizeof(dst)
 *
 * note:
 *      This is similar to strncpy(), but with two modifications:
 *      1) You specify the number of characters to copy, not just
 *              the size of the destination. Hence, you can copy non-NULL
 *              terminated strings.
 *      2) The destination is guaranteed to be NULL terminated. strncpy()
 *              does not terminate a completely full buffer.
 */
static void
elfedit_strnbcpy(char *dst, const char *src, size_t cpsize, size_t dstsize)
{
        if (cpsize >= dstsize)
                cpsize = dstsize - 1;
        if (cpsize > 0)
                (void) strncpy(dst, src, cpsize + 1);
        dst[cpsize] = '\0';
}


/*
 * Calls exit() on behalf of elfedit.
 */
void
elfedit_exit(int status)
{
        if (state.file.present) {
                /* Exiting with unflushed changes pending? Issue debug notice */
                if (state.file.dirty)
                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                            MSG_INTL(MSG_DEBUG_DIRTYEXIT));

                /*
                 * If the edit file is marked for unlink on exit, then
                 * take care of it here.
                 */
                if (state.file.unlink_on_exit) {
                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                            MSG_INTL(MSG_DEBUG_UNLINKFILE),
                            state.file.outfile);
                        (void) unlink(state.file.outfile);
                }
        }

        exit(status);
}


/*
 * Standard message function for elfedit. All user visible
 * output, for error or informational reasons, should go through
 * this function.
 *
 * entry:
 *      type - Type of message. One of the ELFEDIT_MSG_* values.
 *      format, ... - As per the printf() family
 *
 * exit:
 *      The desired message has been output. For informational
 *      messages, control returns to the caller. For errors,
 *      this routine will terminate execution or strip the execution
 *      stack and return control directly to the outer control loop.
 *      In either case, the caller will not receive control.
 */
/*PRINTFLIKE2*/
void
elfedit_msg(elfedit_msg_t type, const char *format, ...)
{
        typedef enum {                  /* What to do after finished */
                DISP_RET = 0,           /* Return to caller */
                DISP_JMP = 1,           /* if (interactive) longjmp else exit */
                DISP_EXIT = 2           /* exit under all circumstances */
        } DISP;

        va_list args;
        FILE *stream = stderr;
        DISP disp = DISP_RET;
        int do_output = 1;
        int need_prefix = 1;

        va_start(args, format);

        switch (type) {
        case ELFEDIT_MSG_ERR:
        case ELFEDIT_MSG_CMDUSAGE:
                disp = DISP_JMP;
                break;
        case ELFEDIT_MSG_FATAL:
                disp = DISP_EXIT;
                break;
        case ELFEDIT_MSG_USAGE:
                need_prefix = 0;
                break;
        case ELFEDIT_MSG_DEBUG:
                if (!(state.flags & ELFEDIT_F_DEBUG))
                        return;
                stream = stdout;
                break;
        case ELFEDIT_MSG_QUIET:
                do_output = 0;
                disp = DISP_JMP;
                break;
        }


        /*
         * If there is a pager process running, we are returning to the
         * caller, and the output is going to stdout, then let the
         * pager handle it instead of writing it directly from this process.
         * That way, the output gets paged along with everything else.
         *
         * If there is a pager process running, and we are not returning
         * to the caller, then end the pager process now, before we generate
         * any new output. This allows for any text buffered in the pager
         * pipe to be output before the new stuff.
         */
        if (state.pager.fptr != NULL) {
                if (disp == DISP_RET) {
                        if (stream == stdout)
                                stream = state.pager.fptr;
                } else {
                        elfedit_pager_cleanup();
                }
        }

        /*
         * If this message is coming from within the libtecla command
         * completion code, call gl_normal_io() to give the library notice.
         * That function sets the tty back to cooked mode and advances
         * the cursor to the beginning of the next line so that our output
         * will appear properly. When we return to the command completion code,
         * tecla will re-enter raw mode and redraw the current command line.
         */
        if (state.input.in_tecla)
                (void) gl_normal_io(state.input.gl);

        if (do_output) {
                if (need_prefix)
                        (void) fprintf(stream, MSG_ORIG(MSG_STR_ELFEDIT));
                (void) vfprintf(stream, format, args);
                (void) fflush(stream);
        }
        va_end(args);

        /*
         * If this is an error, then we do not return to the caller.
         * The action taken depends on whether the outer loop has registered
         * a jump buffer for us or not.
         */
        if (disp != DISP_RET) {
                if (state.msg_jbuf.active && (disp == DISP_JMP)) {
                        /* Free the user command list */
                        free_user_cmds();

                        /* Clean up to reflect effect of non-local goto */
                        state.input.in_tecla = FALSE;

                        /* Jump to the outer loop to resume */
                        siglongjmp(state.msg_jbuf.env, 1);
                } else {
                        elfedit_exit(1);
                }
        }
}


/*
 * Wrapper on elfedit_msg() that issues an error that results from
 * a call to libelf.
 *
 * entry:
 *      file - Name of ELF object
 *      libelf_rtn_name - Name of routine that was called
 *
 * exit:
 *      An error has been issued that shows the routine called
 *      and the libelf error string for it from elf_errmsg().
 *      This routine does not return to the caller.
 */
void
elfedit_elferr(const char *file, const char *libelf_rtn_name)
{
        const char *errstr = elf_errmsg(elf_errno());

        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_LIBELF), file,
            libelf_rtn_name, errstr ? errstr : MSG_INTL(MSG_FMT_UNKNOWN));
}


/*
 * Start an output pager process for elfedit_printf()/elfedit_write() to use.
 *
 * note:
 *      If this elfedit session is not interactive, then no pager is
 *      started. Paging is only intended for interactive use. The caller
 *      is not supposed to worry about this point, but simply to use
 *      this function to flag situations in which paging might be needed.
 */
void
elfedit_pager_init(void)
{
        const char      *errstr;
        const char      *cmd;
        int             err;

        /*
         * If there is no pager process running, start one.
         * Only do this for interactive sessions --- elfedit_pager()
         * won't use a pager in batch mode.
         */
        if (state.msg_jbuf.active && state.input.full_tty &&
            (state.pager.fptr == NULL)) {
                /*
                 * If the user has the PAGER environment variable set,
                 * then we will use that program. Otherwise we default
                 * to /bin/more.
                 */
                cmd = getenv(MSG_ORIG(MSG_STR_PAGER));
                if ((cmd == NULL) || (*cmd == '\0'))
                        cmd = MSG_ORIG(MSG_STR_BINMORE);

                /*
                 * The popen() manpage says that on failure, it "may set errno",
                 * which is somewhat ambiguous. We explicitly zero it here, and
                 * assume that any change is due to popen() failing.
                 */
                errno = 0;
                state.pager.fptr = popen(cmd, MSG_ORIG(MSG_STR_W));
                if (state.pager.fptr == NULL) {
                        err = errno;
                        errstr = (err == 0) ? MSG_INTL(MSG_ERR_UNKNOWNSYSERR) :
                            strerror(err);
                        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTEXEC),
                            MSG_ORIG(MSG_STR_ELFEDIT), cmd, errstr);
                }
        }
}


/*
 * If there is a pager process present, close it out.
 *
 * note:
 *      This function is called from within elfedit_msg(), and as
 *      such, must not use elfedit_msg() to report errors. Furthermore,
 *      any such errors are not a sufficient reason to terminate the process
 *      or to longjmp(). This is a rare case where errors are written
 *      directly to stderr.
 */
static void
elfedit_pager_cleanup(void)
{
        if (state.pager.fptr != NULL) {
                if (pclose(state.pager.fptr) == -1)
                        (void) fprintf(stderr, MSG_INTL(MSG_ERR_PAGERFINI));

                state.pager.fptr = NULL;
        }
}


/*
 * Print general formtted text for the user, using printf()-style
 * formatting. Uses the pager process if one has been started, or
 * stdout otherwise.
 */
void
elfedit_printf(const char *format, ...)
{
        va_list args;
        int     err;
        FILE    *fptr;
        int     pager;
        int     broken_pipe = 0;

        /*
         * If there is a pager process, then use it. Otherwise write
         * directly to stdout.
         */
        pager = (state.pager.fptr != NULL);
        fptr = pager ? state.pager.fptr : stdout;

        va_start(args, format);
        errno = 0;
        err = vfprintf(fptr, format, args);

        /* Did we fail because a child pager process has exited? */
        broken_pipe = pager && (err < 0) && (errno == EPIPE);

        va_end(args);

        /*
         * On error, we simply issue the error without cleaning up
         * the pager process. The message code handles that as a standard
         * part of error processing.
         *
         * We handle failure due to an exited pager process differently
         * than a normal error, because it is usually due to the user
         * intentionally telling it to.
         */
        if (err < 0) {
                if (broken_pipe)
                        elfedit_msg(ELFEDIT_MSG_QUIET, MSG_ORIG(MSG_STR_NULL));
                else
                        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_PRINTF));
        }
}


/*
 * Some our modules use liblddb routines to format ELF output.
 * In order to ensure that such output is sent to the pager pipe
 * when there is one, and stdout otherwise, we redefine the dbg_print()
 * function here.
 *
 * This item should be defined NODIRECT.
 */
/* PRINTFLIKE2 */
void
dbg_print(Lm_list *lml, const char *format, ...)
{
        va_list ap;
        int     err;
        FILE    *fptr;
        int     pager;
        int     broken_pipe = 0;


        /*
         * If there is a pager process, then use it. Otherwise write
         * directly to stdout.
         */
        pager = (state.pager.fptr != NULL);
        fptr = pager ? state.pager.fptr : stdout;

        va_start(ap, format);
        errno = 0;
        err = vfprintf(fptr, format, ap);
        if (err >= 0)
                err = fprintf(fptr, MSG_ORIG(MSG_STR_NL));

        /* Did we fail because a child pager process has exited? */
        broken_pipe = (err < 0) && pager && (errno == EPIPE);

        va_end(ap);

        /*
         * On error, we simply issue the error without cleaning up
         * the pager process. The message code handles that as a standard
         * part of error processing.
         *
         * We handle failure due to an exited pager process differently
         * than a normal error, because it is usually due to the user
         * intentionally telling it to.
         */
        if (err < 0) {
                if (broken_pipe)
                        elfedit_msg(ELFEDIT_MSG_QUIET, MSG_ORIG(MSG_STR_NULL));
                else
                        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_PRINTF));
        }
}


/*
 * Write raw bytes of text in a manner similar to fwrite().
 * Uses the pager process if one has been started, or
 * stdout otherwise.
 */
void
elfedit_write(const void *ptr, size_t size)
{
        FILE    *fptr;
        int     err;

        /*
         * If there is a pager process, then use it. Otherwise write
         * directly to stdout.
         */
        fptr = (state.pager.fptr == NULL) ? stdout : state.pager.fptr;

        if (fwrite(ptr, 1, size, fptr) != size) {
                err = errno;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_FWRITE),
                    strerror(err));
        }
}


/*
 * Convert the NULL terminated string to the form used by the C
 * language to represent literal strings. See conv_str_to_c_literal()
 * for details.
 *
 * This routine differs from conv_str_to_c_literal() in two ways:
 *      1) String is NULL terminated instead of counted
 *      2) Signature of outfunc
 *
 * entry:
 *      str - String to be processed
 *      outfunc - Function to be called to move output characters. Note
 *              that this function has the same signature as elfedit_write(),
 *              and that function can be used to write the characters to
 *              the output.
 *
 * exit:
 *      The string has been processed, with the resulting data passed
 *      to outfunc for processing.
 */
static void
elfedit_str_to_c_literal_cb(const void *ptr, size_t size, void *uvalue)
{
        elfedit_write_func_t *outfunc = (elfedit_write_func_t *)uvalue;

        (* outfunc)(ptr, size);

}
void
elfedit_str_to_c_literal(const char *str, elfedit_write_func_t *outfunc)
{
        conv_str_to_c_literal(str, strlen(str),
            elfedit_str_to_c_literal_cb, (void *) outfunc);
}


/*
 * Wrappers on malloc() and realloc() that check the result for success
 * and issue an error if not. The caller can use the result of these
 * functions without checking for a NULL pointer, as we do not return to
 * the caller in the failure case.
 */
void *
elfedit_malloc(const char *item_name, size_t size)
{
        void *m;

        m = malloc(size);
        if (m == NULL) {
                int err = errno;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_MALLOC),
                    item_name, strerror(err));
        }

        return (m);
}

void *
elfedit_realloc(const char *item_name, void *ptr, size_t size)
{
        void *m;

        m = realloc(ptr, size);
        if (m == NULL) {
                int err = errno;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_MALLOC),
                    item_name, strerror(err));
        }

        return (m);
}


/*
 * Ensure that the given buffer has room for n bytes of data.
 */
static void
strbuf_ensure_size(STRBUF *str, size_t size)
{
#define INITIAL_STR_ALLOC 128

        size_t n;

        n = (str->n == 0) ? INITIAL_STR_ALLOC : str->n;
        while (size > n)        /* Double buffer until string fits */
                n *= 2;
        if (n != str->n) {              /* Alloc new string buffer if needed */
                str->buf = elfedit_realloc(MSG_INTL(MSG_ALLOC_UCMDSTR),
                    str->buf, n);
                str->n = n;
        }

#undef  INITIAL_STR_ALLOC
}


/*
 * Extract the argument/option information for the next item referenced
 * by optarg, and advance the pointer to the next item.
 *
 * entry:
 *      optarg - Address of pointer to argument or option array
 *      item - Struct to be filled in.
 *
 * exit:
 *      The item block has been filled in with the information for
 *      the next item in the optarg array. *optarg has been advanced
 *      to the next item.
 */
void
elfedit_next_optarg(elfedit_cmd_optarg_t **optarg, elfedit_optarg_item_t *item)
{
        /*
         * Array of inheritable options/arguments. Indexed by one less
         * than the corresponding ELFEDIT_STDOA_ value.
         */
        static const elfedit_optarg_item_t stdoa[] = {
                /* ELFEDIT_STDOA_O */
                { MSG_ORIG(MSG_STR_MINUS_O), MSG_ORIG(MSG_STR_OUTSTYLE),
                    /* MSG_INTL(MSG_STDOA_OPTDESC_O) */
                    (elfedit_i18nhdl_t)MSG_STDOA_OPTDESC_O,
                    ELFEDIT_CMDOA_F_VALUE },

                /* ELFEDIT_STDOA_AND */
                { MSG_ORIG(MSG_STR_MINUS_AND), NULL,
                    /* MSG_INTL(MSG_STDOA_OPTDESC_AND) */
                    (elfedit_i18nhdl_t)MSG_STDOA_OPTDESC_AND, 0 },

                /* ELFEDIT_STDOA_CMP */
                { MSG_ORIG(MSG_STR_MINUS_CMP), NULL,
                    /* MSG_INTL(MSG_STDOA_OPTDESC_CMP) */
                    (elfedit_i18nhdl_t)MSG_STDOA_OPTDESC_CMP, 0 },

                /* ELFEDIT_STDOA_OR */
                { MSG_ORIG(MSG_STR_MINUS_OR), NULL,
                    /* MSG_INTL(MSG_STDOA_OPTDESC_OR) */
                    (elfedit_i18nhdl_t)MSG_STDOA_OPTDESC_OR, 0 },
        };

        elfedit_cmd_optarg_t *oa;


        /* Grab first item, advance the callers pointer over it */
        oa = (*optarg)++;

        if (oa->oa_flags & ELFEDIT_CMDOA_F_INHERIT) {
                /* Values are pre-chewed in the stdoa array above */
                *item = stdoa[((uintptr_t)oa->oa_name) - 1];

                /*
                 * Set the inherited flag so that elfedit_optarg_helpstr()
                 * can tell who is responsible for translating the help string.
                 */
                item->oai_flags |= ELFEDIT_CMDOA_F_INHERIT;
        } else {        /* Non-inherited item */
                item->oai_name = oa->oa_name;
                if ((oa->oa_flags & ELFEDIT_CMDOA_F_VALUE) != 0) {
                        item->oai_vname = oa[1].oa_name;

                        /* Advance users pointer past value element */
                        (*optarg)++;
                } else {
                        item->oai_vname = NULL;
                }
                item->oai_help = oa->oa_help;
                item->oai_flags = oa->oa_flags;
        }

        /*
         * The module determines the idmask and excmask fields whether
         * or not inheritance is in play.
         */
        item->oai_idmask = oa->oa_idmask;
        item->oai_excmask = oa->oa_excmask;
}



/*
 * Return the help string for an option/argument item, as returned
 * by elfedit_next_optarg(). This routine handles the details of
 * knowing whether the string is provided by elfedit itself (inherited),
 * or needs to be translated by the module.
 */
const char *
elfedit_optarg_helpstr(elfeditGC_module_t *mod, elfedit_optarg_item_t *item)
{
        /*
         * The help string from an inherited item comes right out
         * of the main elfedit string table.
         */
        if (item->oai_flags & ELFEDIT_CMDOA_F_INHERIT)
                return (MSG_INTL((Msg) item->oai_help));

        /*
         * If the string is defined by the module, then we need to
         * have the module translate it for us.
         */
        return ((* mod->mod_i18nhdl_to_str)(item->oai_help));
}



/*
 * Used by usage_optarg() to insert a character into the output buffer,
 * advancing the buffer pointer and current column, and reducing the
 * amount of remaining space.
 */
static void
usage_optarg_insert_ch(int ch, char **cur, size_t *n, size_t *cur_col)
{

        *(*cur)++ = ch;
        **cur = '\0';
        (*n)--;
        (*cur_col)++;
}

/*
 * Used by usage_optarg() to insert a string into the output
 * buffer, advancing the buffer pointer and current column, and reducing
 * the amount of remaining space.
 */
static void
usage_optarg_insert_str(char **cur, size_t *n, size_t *cur_col,
    const char *format, ...)
{
        size_t len;
        va_list args;

        va_start(args, format);
        len = vsnprintf(*cur, *n, format, args);
        va_end(args);

        *cur += len;
        *n -= len;
        *cur_col += len;
}
/*
 * Used by usage_optarg() to insert an optarg item string into the output
 * buffer, advancing the buffer pointer and current column, and reducing
 * the amount of remaining space.
 */
static void
usage_optarg_insert_item(elfedit_optarg_item_t *item, char **cur,
    size_t *n, size_t *cur_col)
{
        size_t len;

        if (item->oai_flags & ELFEDIT_CMDOA_F_VALUE) {
                len = snprintf(*cur, *n, MSG_ORIG(MSG_STR_HLPOPTARG2),
                    item->oai_name, item->oai_vname);
        } else {
                len = snprintf(*cur, *n, MSG_ORIG(MSG_STR_HLPOPTARG),
                    item->oai_name);
        }
        *cur += len;
        *n -= len;
        *cur_col += len;
}



/*
 * Write the options/arguments to the usage string.
 *
 * entry:
 *      main_buf_n - Size of main buffer from which buf and buf_n are
 *              allocated.
 *      buf - Address of pointer to where next item is to be placed.
 *      buf_n - Address of count of remaining bytes in buffer
 *      buf_cur_col - Address of current output column for current line
 *              of generated string.
 *      optarg - Options list
 *      isopt - True if these are options, false for arguments.
 *      wrap_str - String to indent wrapped lines. If NULL, lines
 *              are not wrapped
 */
static void
usage_optarg(size_t main_buf_n, char **buf, size_t *buf_n, size_t *buf_cur_col,
    elfedit_cmd_optarg_t *optarg, int isopt, const char *wrap_str)
{
        /*
         * An option can be combined into a simple format if it lacks
         * these flags and is only one character in length.
         */
        static const elfedit_cmd_oa_flag_t exflags =
            (ELFEDIT_CMDOA_F_VALUE | ELFEDIT_CMDOA_F_MULT);

        /*
         * A static buffer, which is grown as needed to accomodate
         * the maximum usage string seen.
         */
        static STRBUF simple_str;

        char                    *cur = *buf;
        size_t                  n = *buf_n;
        size_t                  cur_col = *buf_cur_col;
        int                     len;
        int                     use_simple = 0;
        elfedit_optarg_item_t   item;
        elfedit_cmd_oa_mask_t   optmask = 0;
        int                     use_bkt;

        /*
         * If processing options, pull the 1-character ones that don't have
         * an associated value and don't have any mutual exclusion issues into
         * a single combination string to go at the beginning of the usage.
         */
        if (isopt) {
                elfedit_cmd_optarg_t *tmp_optarg = optarg;
                char *s;

                /*
                 * The simple string is guaranteed to fit in the same
                 * amount of space reserved for the main buffer.
                 */
                strbuf_ensure_size(&simple_str, main_buf_n);
                s = simple_str.buf;
                *s++ = ' ';
                *s++ = '[';
                *s++ = '-';
                while (tmp_optarg->oa_name != NULL) {
                        elfedit_next_optarg(&tmp_optarg, &item);
                        if (((item.oai_flags & exflags) == 0) &&
                            (item.oai_name[2] == '\0') &&
                            (item.oai_excmask == 0)) {
                                optmask |= item.oai_idmask;
                                *s++ = item.oai_name[1];
                        }
                }

                /*
                 * If we found more than one, then finish the string and
                 * add it. Don't do this for a single option, because
                 * it looks better in that case if the option shows up
                 * in alphabetical order rather than being hoisted.
                 */
                use_simple = (s > (simple_str.buf + 4));
                if (use_simple) {
                        *s++ = ']';
                        *s++ = '\0';
                        usage_optarg_insert_str(&cur, &n, &cur_col,
                            MSG_ORIG(MSG_STR_HLPOPTARG), simple_str.buf);
                } else {
                        /* Not using it, so reset the cumulative options mask */
                        optmask = 0;
                }
        }

        while (optarg->oa_name != NULL) {
                elfedit_next_optarg(&optarg, &item);

                if (isopt) {
                        /*
                         * If this is an option that was pulled into the
                         * combination string above, then skip over it.
                         */
                        if (use_simple && ((item.oai_flags & exflags) == 0) &&
                            (item.oai_name[2] == '\0') &&
                            (item.oai_excmask == 0))
                                continue;

                        /*
                         * If this is a mutual exclusion option that was
                         * picked up out of order by a previous iteration
                         * of this loop, then skip over it.
                         */
                        if ((optmask & item.oai_idmask) != 0)
                                continue;

                        /* Add this item to the accumulating options mask */
                        optmask |= item.oai_idmask;
                }

                /* Wrap line, or insert blank separator */
                if ((wrap_str != NULL) && (cur_col > USAGE_WRAP_COL)) {
                        len = snprintf(cur, n, MSG_ORIG(MSG_FMT_WRAPUSAGE),
                            wrap_str);
                        cur += len;
                        n -= len;
                        cur_col = len - 1;   /* Don't count the newline */
                } else {
                        usage_optarg_insert_ch(' ', &cur, &n, &cur_col);
                }

                use_bkt = (item.oai_flags & ELFEDIT_CMDOA_F_OPT) || isopt;
                if (use_bkt)
                        usage_optarg_insert_ch('[', &cur, &n, &cur_col);

                /* Add the item to the buffer */
                usage_optarg_insert_item(&item, &cur, &n, &cur_col);

                /*
                 * If this item has a non-zero mutual exclusion mask,
                 * then look for the other items and display them all
                 * together with alternation (|). Note that plain arguments
                 * cannot have a non-0 exclusion mask, so this is
                 * effectively options-only (isopt != 0).
                 */
                if (item.oai_excmask != 0) {
                        elfedit_cmd_optarg_t *tmp_optarg = optarg;
                        elfedit_optarg_item_t tmp_item;

                        /*
                         * When showing alternation, elipses for multiple
                         * copies need to appear inside the [] brackets.
                         */
                        if (item.oai_flags & ELFEDIT_CMDOA_F_MULT)
                                usage_optarg_insert_str(&cur, &n, &cur_col,
                                    MSG_ORIG(MSG_STR_ELIPSES));


                        while (tmp_optarg->oa_name != NULL) {
                                elfedit_next_optarg(&tmp_optarg, &tmp_item);
                                if ((item.oai_excmask & tmp_item.oai_idmask) ==
                                    0)
                                        continue;
                                usage_optarg_insert_str(&cur, &n, &cur_col,
                                    MSG_ORIG(MSG_STR_SP_BAR_SP));
                                usage_optarg_insert_item(&tmp_item,
                                    &cur, &n, &cur_col);

                                /*
                                 * Add it to the mask of seen options.
                                 * This will keep us from showing it twice.
                                 */
                                optmask |= tmp_item.oai_idmask;
                        }
                }
                if (use_bkt)
                        usage_optarg_insert_ch(']', &cur, &n, &cur_col);

                /*
                 * If alternation was not shown above (non-zero exclusion mask)
                 * then the elipses for multiple copies are shown outside
                 * any [] brackets.
                 */
                if ((item.oai_excmask == 0) &&
                    (item.oai_flags & ELFEDIT_CMDOA_F_MULT))
                        usage_optarg_insert_str(&cur, &n, &cur_col,
                            MSG_ORIG(MSG_STR_ELIPSES));

        }

        *buf = cur;
        *buf_n = n;
        *buf_cur_col = cur_col;
}



/*
 * Format the usage string for a command into a static buffer and
 * return the pointer to the user. The resultant string is valid
 * until the next call to this routine, and which point it
 * will be overwritten or the memory is freed.
 *
 * entry:
 *      mod, cmd - Module and command definitions for command to be described
 *      wrap_str - NULL, or string to be used to indent when
 *              lines are wrapped. If NULL, no wrapping is done, and
 *              all output is on a single line.
 *      cur_col - Starting column at which the string will be displayed.
 *              Ignored if wrap_str is NULL.
 */
const char *
elfedit_format_command_usage(elfeditGC_module_t *mod, elfeditGC_cmd_t *cmd,
    const char *wrap_str, size_t cur_col)
{

        /*
         * A static buffer, which is grown as needed to accomodate
         * the maximum usage string seen.
         */
        static STRBUF str;

        elfedit_cmd_optarg_t    *optarg;
        size_t                  len, n, elipses_len;
        char                    *cur;
        elfedit_optarg_item_t   item;

        /*
         * Estimate a worst case size for the usage string:
         *      - module name
         *      - lengths of the strings
         *      - every option or argument is enclosed in brackets
         *      - space in between each item, with an alternation (" | ")
         *      - elipses will be displayed with each option and argument
         */
        n = strlen(mod->mod_name) + strlen(cmd->cmd_name[0]) + 6;
        elipses_len = strlen(MSG_ORIG(MSG_STR_ELIPSES));
        if ((optarg = cmd->cmd_opt) != NULL)
                while (optarg->oa_name != NULL) {
                        elfedit_next_optarg(&optarg, &item);
                        n += strlen(item.oai_name) + 5 + elipses_len;
                }
        if ((optarg = cmd->cmd_args) != NULL)
                while (optarg->oa_name != NULL) {
                        elfedit_next_optarg(&optarg, &item);
                        n += strlen(item.oai_name) + 5 + elipses_len;
                }
        n++;                    /* Null termination */

        /*
         * If wrapping lines, we insert a newline and then wrap_str
         * every USAGE_WRAP_COL characters.
         */
        if (wrap_str != NULL)
                n += ((n + USAGE_WRAP_COL) / USAGE_WRAP_COL) *
                    (strlen(wrap_str) + 1);

        strbuf_ensure_size(&str, n);

        /* Command name */
        cur = str.buf;
        n = str.n;
        if (strcmp(mod->mod_name, MSG_ORIG(MSG_MOD_SYS)) == 0)
                len = snprintf(cur, n, MSG_ORIG(MSG_FMT_SYSCMD),
                    cmd->cmd_name[0]);
        else
                len = snprintf(cur, n, MSG_ORIG(MSG_FMT_MODCMD),
                    mod->mod_name, cmd->cmd_name[0]);
        cur += len;
        n -= len;
        cur_col += len;

        if (cmd->cmd_opt != NULL)
                usage_optarg(str.n, &cur, &n, &cur_col, cmd->cmd_opt,
                    1, wrap_str);
        if (cmd->cmd_args != NULL)
                usage_optarg(str.n, &cur, &n, &cur_col, cmd->cmd_args,
                    0, wrap_str);

        return (str.buf);
}

/*
 * Wrapper on elfedit_msg() that issues an ELFEDIT_MSG_USAGE
 * error giving usage information for the command currently
 * referenced by state.cur_cmd.
 */
void
elfedit_command_usage(void)
{
        elfedit_msg(ELFEDIT_MSG_CMDUSAGE, MSG_INTL(MSG_USAGE_CMD),
            elfedit_format_command_usage(state.cur_cmd->ucmd_mod,
            state.cur_cmd->ucmd_cmd, NULL, 0));
}


/*
 * This function allows the loadable modules to get the command line
 * flags.
 */
elfedit_flag_t
elfedit_flags(void)
{
        return (state.flags);
}

/*
 * This function is used to register a per-command invocation output style
 * that will momentarily override the global output style for the duration
 * of the current command. This function must only be called by an
 * active command.
 *
 * entry:
 *      str - One of the valid strings for the output style
 */
void
elfedit_set_cmd_outstyle(const char *str)
{
        if ((state.cur_cmd != NULL) && (str != NULL)) {
                if (elfedit_atooutstyle(str, &state.cur_cmd->ucmd_ostyle) == 0)
                        elfedit_msg(ELFEDIT_MSG_ERR,
                            MSG_INTL(MSG_ERR_BADOSTYLE), str);
                state.cur_cmd->ucmd_ostyle_set = 1;
        }
}

/*
 * This function allows the loadable modules to get the output style.
 */
elfedit_outstyle_t
elfedit_outstyle(void)
{
        /*
         * If there is an active  per-command output style,
         * return it.
         */
        if ((state.cur_cmd != NULL) && (state.cur_cmd->ucmd_ostyle_set))
                return (state.cur_cmd->ucmd_ostyle);


        return (state.outstyle);
}

/*
 * Return the command descriptor of the currently executing command.
 * For use only by the modules or code called by the modules.
 */
elfeditGC_cmd_t *
elfedit_curcmd(void)
{
        return (state.cur_cmd->ucmd_cmd);
}

/*
 * Build a dynamically allocated elfedit_obj_state_t struct that
 * contains a cache of the ELF file contents. This pre-chewed form
 * is fed to each command, reducing the amount of ELF boilerplate
 * code each command needs to contain.
 *
 * entry:
 *      file - Name of file to process
 *
 * exit:
 *      Fills state.elf with the necessary information for the open file.
 *
 * note: The resulting elfedit_obj_state_t is allocated from a single
 *      piece of memory, such that a single call to free() suffices
 *      to release it as well as any memory it references.
 */
static void
init_obj_state(const char *file)
{
        int     fd;
        Elf     *elf;
        int     open_flag;

        /*
         * In readonly mode, we open the file readonly so that it is
         * impossible to modify the file by accident. This also allows
         * us to access readonly files, perhaps in a case where we don't
         * intend to change it.
         *
         * We always use ELF_C_RDWR with elf_begin(), even in a readonly
         * session. This allows us to modify the in-memory image, which
         * can be useful when examining a file, even though we don't intend
         * to modify the on-disk data. The file is not writable in
         * this case, and we don't call elf_update(), so it is safe to do so.
         */
        open_flag = ((state.flags & ELFEDIT_F_READONLY) ? O_RDONLY : O_RDWR);
        if ((fd = open(file, open_flag)) == -1) {
                int err = errno;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTOPNFILE),
                    file, strerror(err));
        }
        (void) elf_version(EV_CURRENT);
        elf = elf_begin(fd, ELF_C_RDWR, NULL);
        if (elf == NULL) {
                (void) close(fd);
                elfedit_elferr(file, MSG_ORIG(MSG_ELF_BEGIN));
                /*NOTREACHED*/
        }

        /* We only handle standalone ELF files */
        switch (elf_kind(elf)) {
        case ELF_K_AR:
                (void) close(fd);
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_NOAR), file);
                break;
        case ELF_K_ELF:
                break;
        default:
                (void) close(fd);
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_UNRECELFFILE),
                    file);
                break;
        }

        /*
         * Tell libelf that we take responsibility for object layout.
         * Otherwise, it will compute "proper" values for layout and
         * alignment fields, and these values can overwrite the values
         * set in the elfedit session. We are modifying existing
         * objects --- the layout concerns have already been dealt
         * with when the object was built.
         */
        (void) elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);

        /* Fill in state.elf.obj_state */
        state.elf.elfclass = gelf_getclass(elf);
        switch (state.elf.elfclass) {
        case ELFCLASS32:
                elfedit32_init_obj_state(file, fd, elf);
                break;
        case ELFCLASS64:
                elfedit64_init_obj_state(file, fd, elf);
                break;
        default:
                (void) close(fd);
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_BADELFCLASS),
                    file);
                break;
        }
}


#ifdef DEBUG_MODULE_LIST
/*
 * Debug routine. Dump the module list to stdout.
 */
static void
dbg_module_list(char *title)
{
        MODLIST_T *m;

        printf("<MODULE LIST: %s>\n", title);
        for (m = state.modlist; m != NULL; m = m->next) {
                printf("Module: >%s<\n", m->mod->mod_name);
                printf("    hdl:  %llx\n", m->dl_hdl);
                printf("    path: >%s<\n", m->path ? m->path : "<builtin>");
        }
        printf("<END OF MODULE LIST>\n");
}
#endif


/*
 * Search the module list for the named module.
 *
 * entry:
 *      name - Name of module to find
 *      insdef - Address of variable to receive address of predecessor
 *              node to the desired one.
 *
 * exit:
 *      If the module is it is found, this routine returns the pointer to
 *      its MODLIST_T structure. *insdef references the predecessor node, or
 *      is NULL if the found item is at the head of the list.
 *
 *      If the module is not found, NULL is returned. *insdef references
 *      the predecessor node of the position where an entry for this module
 *      would be placed, or NULL if it would go at the beginning.
 */
static MODLIST_T *
module_loaded(const char *name, MODLIST_T **insdef)
{
        MODLIST_T       *moddef;
        int             cmp;

        *insdef = NULL;
        moddef = state.modlist;
        if (moddef != NULL) {
                cmp = strcasecmp(name, moddef->ml_mod->mod_name);
                if (cmp == 0) {         /* Desired module is first in list */
                        return (moddef);
                } else if (cmp > 0) {   /* cmp > 0: Insert in middle/end */
                        *insdef = moddef;
                        moddef = moddef->ml_next;
                        cmp = -1;
                        while (moddef && (cmp < 0)) {
                                cmp = strcasecmp(moddef->ml_mod->mod_name,
                                    name);
                                if (cmp == 0)
                                        return (moddef);
                                if (cmp < 0) {
                                        *insdef = moddef;
                                        moddef = (*insdef)->ml_next;
                                }
                        }
                }
        }

        return (NULL);
}


/*
 * Determine if a file is a sharable object based on its file path.
 * If path ends in a .so, followed optionally by a period and 1 or more
 * digits, we say that it is and return a pointer to the first character
 * of the suffix. Otherwise NULL is returned.
 */
static const char *
path_is_so(const char *path)
{
        int             dotso_len;
        const char      *tail;
        size_t          len;

        len = strlen(path);
        if (len == 0)
                return (NULL);
        tail = path + len;
        if (isdigit(*(tail - 1))) {
                while ((tail > path) && isdigit(*(tail - 1)))
                        tail--;
                if ((tail <= path) || (*tail != '.'))
                        return (NULL);
        }
        dotso_len = strlen(MSG_ORIG(MSG_STR_DOTSO));
        if ((tail - path) < dotso_len)
                return (NULL);
        tail -= dotso_len;
        if (strncmp(tail, MSG_ORIG(MSG_STR_DOTSO), dotso_len) == 0)
                return (tail);

        return (NULL);
}


/*
 * Locate the start of the unsuffixed file name within path. Returns pointer
 * to first character of that name in path.
 *
 * entry:
 *      path - Path to be examined.
 *      tail - NULL, or pointer to position at tail of path from which
 *              the search for '/' characters should start. If NULL,
 *              strlen() is used to locate the end of the string.
 *      buf - NULL, or buffer to receive a copy of the characters that
 *              lie between the start of the filename and tail.
 *      bufsize - sizeof(buf)
 *
 * exit:
 *      The pointer to the first character of the unsuffixed file name
 *      within path is returned. If buf is non-NULL, the characters
 *      lying between that point and tail (or the end of path if tail
 *      is NULL) are copied into buf.
 */
static const char *
elfedit_basename(const char *path, const char *tail, char *buf, size_t bufsiz)
{
        const char      *s;

        if (tail == NULL)
                tail = path + strlen(path);
        s = tail;
        while ((s > path) && (*(s - 1) != '/'))
                s--;
        if (buf != NULL)
                elfedit_strnbcpy(buf, s, tail - s, bufsiz);
        return (s);
}


/*
 * Issue an error on behalf of load_module(), taking care to release
 * resources that routine may have aquired:
 *
 * entry:
 *      moddef - NULL, or a module definition to be released via free()
 *      dl_hdl - NULL, or a handle to a sharable object to release via
 *              dlclose().
 *      dl_path - If dl_hdl is non-NULL, the path to the sharable object
 *              file that was loaded.
 *      format - A format string to pass to elfedit_msg(), containing
 *              no more than (3) %s format codes, and no other format codes.
 *      [s1-s4] - Strings to pass to elfedit_msg() to satisfy the four
 *              allowed %s codes in format. Should be set to NULL if the
 *              format string does not need them.
 *
 * note:
 *      This routine makes a copy of the s1-s4 strings before freeing any
 *      memory or unmapping the sharable library. It is therefore safe to
 *      use strings from moddef, or from the sharable library (which will
 *      be unmapped) to satisfy the other arguments s1-s4.
 */
static void
load_module_err(MODLIST_T *moddef, void *dl_hdl, const char *dl_path,
    const char *format, const char *s1, const char *s2, const char *s3,
    const char *s4)
{
#define SCRBUFSIZE (PATH_MAX + 256)   /* A path, plus some extra */

        char s1_buf[SCRBUFSIZE];
        char s2_buf[SCRBUFSIZE];
        char s3_buf[SCRBUFSIZE];
        char s4_buf[SCRBUFSIZE];

        /*
         * The caller may provide strings for s1-s3 that are from
         * moddef. If we free moddef, the printf() will die on access
         * to free memory. We could push back on the user and force
         * each call to carefully make copies of such data. However, this
         * is an easy case to miss. Furthermore, this is an error case,
         * and machine efficiency is not the main issue. We therefore make
         * copies of the s1-s3 strings here into auto variables, and then
         * use those copies. The user is freed from worrying about it.
         *
         * We use oversized stack based buffers instead of malloc() to
         * reduce the number of ways that things can go wrong while
         * reporting the error.
         */
        if (s1 != NULL)
                (void) strlcpy(s1_buf, s1, sizeof (s1_buf));
        if (s2 != NULL)
                (void) strlcpy(s2_buf, s2, sizeof (s2_buf));
        if (s3 != NULL)
                (void) strlcpy(s3_buf, s3, sizeof (s3_buf));
        if (s4 != NULL)
                (void) strlcpy(s4_buf, s4, sizeof (s4_buf));


        free(moddef);

        if ((dl_hdl != NULL) && (dlclose(dl_hdl) != 0))
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTDLCLOSE),
                    dl_path, dlerror());

        elfedit_msg(ELFEDIT_MSG_ERR, format, s1_buf, s2_buf, s3_buf, s4_buf);
#undef  SCRBUFSIZE
}


/*
 * Load a module sharable object for load_module().
 *
 * entry:
 *      path - Path of file to open
 *      moddef - If this function issues a non-returning error, it will
 *              first return the memory referenced by moddef. This argument
 *              is not used otherwise.
 *      must_exist - If True, we consider it to be an error if the file given
 *              by path does not exist. If False, no error is issued
 *              and a NULL value is quietly returned.
 *
 * exit:
 *      Returns a handle to the loaded object on success, or NULL if no
 *      file was loaded.
 */
static void *
load_module_dlopen(const char *path, MODLIST_T *moddef, int must_exist)
{
        int     fd;
        void    *hdl;

        /*
         * If the file is not required to exist, and it doesn't, then
         * we want to quietly return without an error.
         */
        if (!must_exist) {
                fd = open(path, O_RDONLY);
                if (fd >= 0) {
                        (void) close(fd);
                } else if (errno == ENOENT) {
                        return (NULL);
                }
        }

        if ((hdl = dlopen(path, RTLD_LAZY|RTLD_FIRST)) == NULL)
                load_module_err(moddef, NULL, NULL,
                    MSG_INTL(MSG_ERR_CNTDLOPEN), path, dlerror(), NULL, NULL);

        return (hdl);
}


/*
 * Sanity check option arguments to prevent common errors. The rest of
 * elfedit assumes these tests have been done, and does not check
 * again.
 */
static void
validate_optarg(elfedit_cmd_optarg_t *optarg, int isopt, MODLIST_T *moddef,
    const char *mod_name, const char *cmd_name,
    void *dl_hdl, const char *dl_path)
{
#define FAIL(_msg) errmsg = _msg; goto fail

        Msg errmsg;
        elfedit_cmd_oa_mask_t   optmask = 0;

        for (; optarg->oa_name != NULL; optarg++) {
                /*
                 * If ELFEDIT_CMDOA_F_INHERIT is set:
                 *      - oa_name must be a value in the range of
                 *              known ELFEDIT_STDOA_ values.
                 *      - oa_help must be NULL
                 *      - ELFEDIT_CMDOA_F_INHERIT must be the only flag set
                 */
                if (optarg->oa_flags & ELFEDIT_CMDOA_F_INHERIT) {
                        if ((((uintptr_t)optarg->oa_name) >
                            ELFEDIT_NUM_STDOA) ||
                            (optarg->oa_help != 0) ||
                            (optarg->oa_flags != ELFEDIT_CMDOA_F_INHERIT))
                                /*
                                 * Can't use FAIL --- oa_name is not a valid
                                 * string, and load_module_err() looks at args.
                                 */
                                load_module_err(moddef, dl_hdl, dl_path,
                                    MSG_INTL(MSG_ERR_BADSTDOA), dl_path,
                                    mod_name, cmd_name, NULL);
                        continue;
                }

                if (isopt) {
                        /*
                         * Option name must start with a '-', and must
                         * have at one following character.
                         */
                        if (optarg->oa_name[0] != '-') {
                                /* MSG_INTL(MSG_ERR_OPT_MODPRE) */
                                FAIL(MSG_ERR_OPT_MODPRE);
                        }
                        if (optarg->oa_name[1] == '\0') {
                                /* MSG_INTL(MSG_ERR_OPT_MODLEN) */
                                FAIL(MSG_ERR_OPT_MODLEN);
                        }

                        /*
                         * oa_idmask must be 0, or it must have a single
                         * bit set (a power of 2).oa_excmask must be 0
                         * if oa_idmask is 0
                         */
                        if (optarg->oa_idmask == 0) {
                                if (optarg->oa_excmask != 0) {
                                        /* MSG_INTL(MSG_ERR_OPT_EXCMASKN0) */
                                        FAIL(MSG_ERR_OPT_EXCMASKN0);
                                }
                        } else {
                                if (elfedit_bits_set(optarg->oa_idmask,
                                    sizeof (optarg->oa_idmask)) != 1) {
                                        /* MSG_INTL(MSG_ERR_OPT_IDMASKPOW2) */
                                        FAIL(MSG_ERR_OPT_IDMASKPOW2);
                                }

                                /* Non-zero idmask must be unique */
                                if ((optarg->oa_idmask & optmask) != 0) {
                                        /* MSG_INTL(MSG_ERR_OPT_IDMASKUNIQ) */
                                        FAIL(MSG_ERR_OPT_IDMASKUNIQ);
                                }

                                /* Add this one to the overall mask */
                                optmask |= optarg->oa_idmask;
                        }
                } else {
                        /*
                         * Argument name cannot start with a'-', and must
                         * not be a null string.
                         */
                        if (optarg->oa_name[0] == '-') {
                                /* MSG_INTL(MSG_ERR_ARG_MODPRE) */
                                FAIL(MSG_ERR_ARG_MODPRE);
                        }
                        if (optarg->oa_name[1] == '\0') {
                                /* MSG_INTL(MSG_ERR_ARG_MODLEN) */
                                FAIL(MSG_ERR_ARG_MODLEN);
                        }


                        /* oa_idmask and oa_excmask must both be 0 */
                        if ((optarg->oa_idmask != 0) ||
                            (optarg->oa_excmask != 0)) {
                                /* MSG_INTL(MSG_ERR_ARG_MASKNOT0) */
                                FAIL(MSG_ERR_ARG_MASKNOT0);
                        }

                }

                /*
                 * If it takes a value, make sure that we are
                 * processing options, because CMDOA_F_VALUE is not
                 * allowed for plain arguments. Then check the following
                 * item in the list:
                 *      - There must be a following item.
                 *      - oa_name must be non-NULL. This is the only field
                 *              that is used by elfedit.
                 *      - oa_help, oa_flags, oa_idmask, and oa_excmask
                 *              must be 0.
                 */
                if (optarg->oa_flags & ELFEDIT_CMDOA_F_VALUE) {
                        elfedit_cmd_optarg_t *oa1 = optarg + 1;

                        if (!isopt) {
                                /* MSG_INTL(MSG_ERR_ARG_CMDOA_VAL) */
                                FAIL(MSG_ERR_ARG_CMDOA_VAL);
                        }

                        if ((optarg + 1)->oa_name == NULL) {
                                /* MSG_INTL(MSG_ERR_BADMODOPTVAL) */
                                FAIL(MSG_ERR_BADMODOPTVAL);
                        }

                        if (oa1->oa_name == NULL) {
                                /* MSG_INTL(MSG_ERR_CMDOA_VALNAM) */
                                FAIL(MSG_ERR_CMDOA_VALNAM);
                        }
                        if ((oa1->oa_help != (elfedit_i18nhdl_t)NULL) ||
                            (oa1->oa_flags != 0) ||
                            (oa1->oa_idmask != 0) || (oa1->oa_excmask != 0)) {
                                /* MSG_INTL(MSG_ERR_CMDOA_VALNOT0) */
                                FAIL(MSG_ERR_CMDOA_VALNOT0);
                        }
                        optarg++;
                }
        }


        return;

fail:
        load_module_err(moddef, dl_hdl, dl_path, MSG_INTL(errmsg),
            dl_path, mod_name, cmd_name, optarg->oa_name);
}

/*
 * Look up the specified module, loading the module if necessary,
 * and return its definition, or NULL on failure.
 *
 * entry:
 *      name - Name of module to load. If name contains a '/' character or has
 *              a ".so" suffix, then it is taken to be an absolute file path,
 *              and is used directly as is. If name does not contain a '/'
 *              character, then we look for it against the locations in
 *              the module path, addint the '.so' suffix, and taking the first
 *              one we find.
 *      must_exist - If True, we consider it to be an error if we are unable
 *              to locate a file to load and the module does not already exist.
 *              If False, NULL is returned quietly in this case.
 *      allow_abs - True if absolute paths are allowed. False to disallow
 *              them.
 *
 * note:
 *      If the path is absolute, then we load the file and take the module
 *      name from the data returned by its elfedit_init() function. If a
 *      module of that name is already loaded, it is unloaded and replaced
 *      with the new one.
 *
 *      If the path is non absolute, then we check to see if the module has
 *      already been loaded, and if so, we return that module definition.
 *      In this case, nothing new is loaded. If the module has not been loaded,
 *      we search the path for it and load it. If the module name provided
 *      by the elfedit_init() function does not match the name of the file,
 *      an error results.
 */
elfeditGC_module_t *
elfedit_load_module(const char *name, int must_exist, int allow_abs)
{
        elfedit_init_func_t     *init_func;
        elfeditGC_module_t      *mod;
        MODLIST_T               *moddef, *insdef;
        const char              *path;
        char                    path_buf[PATH_MAX + 1];
        void                    *hdl;
        size_t                  i;
        int                     is_abs_path;
        elfeditGC_cmd_t         *cmd;

        /*
         * If the name includes a .so suffix, or has any '/' characters,
         * then it is an absolute path that we use as is to load the named
         * file. Otherwise, we iterate over the path, adding the .so suffix
         * and load the first file that matches.
         */
        is_abs_path = (path_is_so(name) != NULL) ||
            (name != elfedit_basename(name, NULL, NULL, 0));

        if (is_abs_path && !allow_abs)
                load_module_err(NULL, NULL, NULL,
                    MSG_INTL(MSG_ERR_UNRECMOD), name, NULL, NULL, NULL);

        /*
         * If this is a non-absolute path, search for the module already
         * having been loaded, and return it if so.
         */
        if (!is_abs_path) {
                moddef = module_loaded(name, &insdef);
                if (moddef != NULL)
                        return (moddef->ml_mod);
                /*
                 * As a result of module_loaded(), insdef now contains the
                 * immediate predecessor node for the new one, or NULL if
                 * it goes at the front. In the absolute-path case, we take
                 * care of this below, after the sharable object is loaded.
                 */
        }

        /*
         * malloc() a module definition block before trying to dlopen().
         * Doing things in the other order can cause the dlopen()'d object
         * to leak: If elfedit_malloc() fails, it can cause a jump to the
         * outer command loop without returning to the caller. Hence,
         * there will be no opportunity to clean up. Allocaing the module
         * first allows us to free it if necessary.
         */
        moddef = elfedit_malloc(MSG_INTL(MSG_ALLOC_MODDEF),
            sizeof (*moddef) + PATH_MAX + 1);
        moddef->ml_path = ((char *)moddef) + sizeof (*moddef);

        if (is_abs_path) {
                path = name;
                hdl = load_module_dlopen(name, moddef, must_exist);
        } else {
                hdl = NULL;
                path = path_buf;
                for (i = 0; i < state.modpath.n; i++) {
                        if (snprintf(path_buf, sizeof (path_buf),
                            MSG_ORIG(MSG_FMT_BLDSOPATH), state.modpath.seg[i],
                            name) > sizeof (path_buf))
                                load_module_err(moddef, NULL, NULL,
                                    MSG_INTL(MSG_ERR_PATHTOOLONG),
                                    state.modpath.seg[i], name, NULL, NULL);
                        hdl = load_module_dlopen(path, moddef, 0);
                }
                if (must_exist && (hdl == NULL))
                        load_module_err(moddef, NULL, NULL,
                            MSG_INTL(MSG_ERR_UNRECMOD), name, NULL, NULL, NULL);
        }

        if (hdl == NULL) {
                free(moddef);
                return (NULL);
        }

        if (state.elf.elfclass == ELFCLASS32) {
                init_func = (elfedit_init_func_t *)
                    dlsym(hdl, MSG_ORIG(MSG_STR_ELFEDITINIT32));
        } else {
                init_func = (elfedit_init_func_t *)
                    dlsym(hdl, MSG_ORIG(MSG_STR_ELFEDITINIT64));
        }
        if (init_func == NULL)
                load_module_err(moddef, hdl, path,
                    MSG_INTL(MSG_ERR_SONOTMOD), path, NULL, NULL, NULL);

        /*
         * Note that the init function will be passing us an
         * elfedit[32|64]_module_t pointer, which we cast to the
         * generic module pointer type in order to be able to manage
         * either type with one set of code.
         */
        if (!(mod = (elfeditGC_module_t *)(* init_func)(ELFEDIT_VER_CURRENT)))
                load_module_err(moddef, hdl, path,
                    MSG_INTL(MSG_ERR_BADMODLOAD), path, NULL, NULL, NULL);

        /*
         * Enforce some rules, to help module developers:
         *      - The primary name of a command must not be
         *              the empty string ("").
         *      - Options must start with a '-' followed by at least
         *              one character.
         *      - Arguments and options must be well formed.
         */
        for (cmd = mod->mod_cmds; cmd->cmd_func != NULL; cmd++) {
                if (**cmd->cmd_name == '\0')
                        load_module_err(moddef, hdl, path,
                            MSG_INTL(MSG_ERR_NULLPRICMDNAM), mod->mod_name,
                            NULL, NULL, NULL);

                if (cmd->cmd_args != NULL)
                        validate_optarg(cmd->cmd_args, 0, moddef, mod->mod_name,
                            cmd->cmd_name[0], hdl, path);
                if (cmd->cmd_opt != NULL)
                        validate_optarg(cmd->cmd_opt, 1, moddef, mod->mod_name,
                            cmd->cmd_name[0], hdl, path);
        }

        /*
         * Check the name the module provides. How we handle this depends
         * on whether the path is absolute or the result of a path search.
         */
        if (is_abs_path) {
                MODLIST_T *old_moddef = module_loaded(mod->mod_name, &insdef);

                if (old_moddef != NULL) {       /* Replace existing */
                        free(moddef);           /* Rare case: Don't need it */
                        /*
                         * Be sure we don't unload builtin modules!
                         * These have a NULL dl_hdl field.
                         */
                        if (old_moddef->ml_dl_hdl == NULL)
                                load_module_err(NULL, hdl, path,
                                    MSG_INTL(MSG_ERR_CNTULSMOD),
                                    old_moddef->ml_mod->mod_name, NULL,
                                    NULL, NULL);

                        /* Unload existing */
                        if (dlclose(old_moddef->ml_dl_hdl) != 0)
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_CNTDLCLOSE),
                                    old_moddef->ml_path, dlerror());
                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                            MSG_INTL(MSG_DEBUG_MODUNLOAD),
                            old_moddef->ml_mod->mod_name, old_moddef->ml_path);
                        old_moddef->ml_mod = mod;
                        old_moddef->ml_dl_hdl = hdl;
                        (void) strlcpy((char *)old_moddef->ml_path, path,
                            PATH_MAX + 1);
                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                            MSG_INTL(MSG_DEBUG_MODLOAD),
                            old_moddef->ml_mod->mod_name, path);
                        return (old_moddef->ml_mod);
                }
                /*
                 * insdef now contains the insertion point for the absolute
                 * path case.
                 */
        } else {
                /* If the names don't match, then error */
                if (strcasecmp(name, mod->mod_name) != 0)
                        load_module_err(moddef, hdl, path,
                            MSG_INTL(MSG_ERR_BADMODNAME),
                            mod->mod_name, name, path, NULL);
        }

        /*
         * Link module into the module list. If insdef is NULL,
         * it goes at the head. If insdef is non-NULL, it goes immediately
         * after
         */
        if (insdef == NULL) {
                moddef->ml_next = state.modlist;
                state.modlist = moddef;
        } else {
                moddef->ml_next = insdef->ml_next;
                insdef->ml_next = moddef;
        }
        moddef->ml_mod = mod;
        moddef->ml_dl_hdl = hdl;
        (void) strlcpy((char *)moddef->ml_path, path, PATH_MAX + 1);

        elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_MODLOAD),
            moddef->ml_mod->mod_name, path);

        return (moddef->ml_mod);
}


/*
 * Unload the specified module
 */
void
elfedit_unload_module(const char *name)
{
        MODLIST_T       *moddef, *insdef;

        moddef = module_loaded(name, &insdef);
        if (moddef == NULL)
                return;

        /* Built in modules cannot be unloaded. They have a NULL dl_hdl field */
        if (moddef->ml_dl_hdl == NULL)
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTULSMOD),
                    moddef->ml_mod->mod_name);

        /*
         * When we unload it, the name string goes with it. So
         * announce it while we still can without having to make a copy.
         */
        elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_MODUNLOAD),
            moddef->ml_mod->mod_name, moddef->ml_path);

        /*
         * Close it before going further. On failure, we'll jump, and the
         * record will remain in the module list. On success,
         * we'll retain control, and can safely remove it.
         */
        if (dlclose(moddef->ml_dl_hdl) != 0)
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTDLCLOSE),
                    moddef->ml_path, dlerror());

        /* Unlink the record from the module list */
        if (insdef == NULL)
                state.modlist = moddef->ml_next;
        else
                insdef->ml_next = moddef->ml_next;

        /* Release the memory */
        free(moddef);
}


/*
 * Load all sharable objects found in the specified directory.
 *
 * entry:
 *      dirpath - Path of directory to process.
 *      must_exist - If True, it is an error if diropen() fails to open
 *              the given directory. Of False, we quietly ignore it and return.
 *      abs_path - If True, files are loaded using their literal paths.
 *              If False, their module name is extracted from the dirpath
 *              and a path based search is used to locate it.
 */
void
elfedit_load_moddir(const char *dirpath, int must_exist, int abs_path)
{
        char            path[PATH_MAX + 1];
        DIR             *dir;
        struct dirent   *dp;
        const char      *tail;

        dir = opendir(dirpath);
        if (dir == NULL) {
                int err = errno;

                if (!must_exist && (err == ENOENT))
                        return;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTOPNDIR),
                    dirpath, strerror(err));
                /*NOTREACHED*/
        }

        while (dp = readdir(dir)) {
                if ((tail = path_is_so(dp->d_name)) != NULL) {
                        if (abs_path) {
                                (void) snprintf(path, sizeof (path),
                                    MSG_ORIG(MSG_FMT_BLDPATH), dirpath,
                                    dp->d_name);
                        } else {
                                (void) elfedit_basename(dp->d_name, tail,
                                    path, sizeof (path));
                        }
                        (void) elfedit_load_module(path, must_exist, 1);
                }
        }
        (void) closedir(dir);
}


/*
 * Follow the module load path, and load the first module found for each
 * given name.
 */
void
elfedit_load_modpath(void)
{
        size_t          i;

        for (i = 0; i < state.modpath.n; i++)
                elfedit_load_moddir(state.modpath.seg[i], 0, 0);
}

/*
 * Given a module definition, look for the specified command.
 * Returns the command if found, and NULL otherwise.
 */
static elfeditGC_cmd_t *
find_cmd(elfeditGC_module_t *mod, const char *name)
{
        elfeditGC_cmd_t *cmd;
        const char **cmd_name;

        for (cmd = mod->mod_cmds; cmd->cmd_func != NULL; cmd++)
                for (cmd_name = cmd->cmd_name; *cmd_name; cmd_name++)
                        if (strcasecmp(name, *cmd_name) == 0) {
                                if (cmd_name != cmd->cmd_name)
                                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                                            MSG_INTL(MSG_DEBUG_CMDALIAS),
                                            mod->mod_name, *cmd_name,
                                            mod->mod_name, *cmd->cmd_name);
                                return (cmd);
                        }

        return (NULL);
}


/*
 * Given a command name, return its command definition.
 *
 * entry:
 *      name - Command to be looked up
 *      must_exist - If True, we consider it to be an error if the command
 *              does not exist. If False, NULL is returned quietly in
 *              this case.
 *      mod_ret - NULL, or address of a variable to receive the
 *              module definition block of the module containing
 *              the command.
 *
 * exit:
 *      On success, returns a pointer to the command definition, and
 *      if mod_ret is non-NULL, *mod_ret receives a pointer to the
 *      module definition. On failure, must_exist determines the
 *      action taken: If must_exist is True, an error is issued and
 *      control does not return to the caller. If must_exist is False,
 *      NULL is quietly returned.
 *
 * note:
 *      A ':' in name is used to delimit the module and command names.
 *      If it is omitted, or if it is the first non-whitespace character
 *      in the name, then the built in sys: module is implied.
 */
elfeditGC_cmd_t *
elfedit_find_command(const char *name, int must_exist,
    elfeditGC_module_t **mod_ret)
{
        elfeditGC_module_t      *mod;
        const char              *mod_str;
        const char              *cmd_str;
        char                    mod_buf[ELFEDIT_MAXMODNAM + 1];
        size_t                  n;
        elfeditGC_cmd_t         *cmd;


        cmd_str = strstr(name, MSG_ORIG(MSG_STR_COLON));
        if (cmd_str == NULL) {          /* No module name -> sys: */
                mod_str = MSG_ORIG(MSG_MOD_SYS);
                cmd_str = name;
        } else if (cmd_str == name) {   /* Empty module name -> sys: */
                mod_str = MSG_ORIG(MSG_MOD_SYS);
                cmd_str++;              /* Skip the colon */
        } else {                        /* Have both module and command */
                n = cmd_str - name;
                if (n >= sizeof (mod_buf)) {
                        if (must_exist)
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_MODNAMTOOLONG), name);
                        return (NULL);
                }
                (void) strlcpy(mod_buf, name, n + 1);
                mod_str = mod_buf;
                cmd_str++;
        }

        /* Lookup/load module. Won't return on error */
        mod = elfedit_load_module(mod_str, must_exist, 0);
        if (mod == NULL)
                return (NULL);

        /* Locate the command */
        cmd = find_cmd(mod, cmd_str);
        if (cmd == NULL) {
                if (must_exist) {
                        /*
                         * Catch empty command in order to provide
                         * a better error message.
                         */
                        if (*cmd_str == '\0') {
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_MODNOCMD), mod_str);
                        } else {
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_UNRECCMD),
                                    mod_str, cmd_str);
                        }
                }
        } else {
                if (mod_ret != NULL)
                        *mod_ret = mod;
        }
        return (cmd);
}


/*
 * Release all user command blocks found on state.ucmd
 */
static void
free_user_cmds(void)
{
        USER_CMD_T *next;

        while (state.ucmd.list) {
                next = state.ucmd.list->ucmd_next;
                free(state.ucmd.list);
                state.ucmd.list = next;
        }
        state.ucmd.tail = NULL;
        state.ucmd.n = 0;
        state.cur_cmd = NULL;
}


/*
 * Process all user command blocks found on state.ucmd, and then
 * remove them from the list.
 */
static void
dispatch_user_cmds()
{
        USER_CMD_T              *ucmd;
        elfedit_cmdret_t        cmd_ret;

        ucmd = state.ucmd.list;
        if (ucmd) {
                /* Do them, in order */
                for (; ucmd; ucmd = ucmd->ucmd_next) {
                        state.cur_cmd = ucmd;
                        if (!state.msg_jbuf.active)
                                elfedit_msg(ELFEDIT_MSG_DEBUG,
                                    MSG_INTL(MSG_DEBUG_EXECCMD),
                                    ucmd->ucmd_orig_str);
                        /*
                         * The cmd_func field is the generic definition.
                         * We need to cast it to the type that matches
                         * the proper ELFCLASS before calling it.
                         */
                        if (state.elf.elfclass == ELFCLASS32) {
                                elfedit32_cmd_func_t *cmd_func =
                                    (elfedit32_cmd_func_t *)
                                    ucmd->ucmd_cmd->cmd_func;

                                cmd_ret = (* cmd_func)(state.elf.obj_state.s32,
                                    ucmd->ucmd_argc, ucmd->ucmd_argv);
                        } else {
                                elfedit64_cmd_func_t *cmd_func =
                                    (elfedit64_cmd_func_t *)
                                    ucmd->ucmd_cmd->cmd_func;

                                cmd_ret = (* cmd_func)(state.elf.obj_state.s64,
                                    ucmd->ucmd_argc, ucmd->ucmd_argv);
                        }
                        state.cur_cmd = NULL;
                        /* If a pager was started, wrap it up */
                        elfedit_pager_cleanup();

                        switch (cmd_ret) {
                        case ELFEDIT_CMDRET_MOD_OS_MACH:
                                /*
                                 * Inform the elfconst module that the machine
                                 * or osabi has has changed. It may be necessary
                                 * to fetch new strings from libconv.
                                 */
                                state.elf.elfconst_ehdr_change = 1;
                                /*FALLTHROUGH*/
                        case ELFEDIT_CMDRET_MOD:
                                /*
                                 * Command modified the output ELF image,
                                 * mark the file as needing a flush to disk.
                                 */
                                state.file.dirty = 1;
                                break;
                        case ELFEDIT_CMDRET_FLUSH:
                                /*
                                 * Command flushed the output file,
                                 * clear the dirty bit.
                                 */
                                state.file.dirty = 0;
                        }
                }
                free_user_cmds();
        }
}


/*
 * Prepare a GETTOK_STATE struct for gettok().
 *
 * entry:
 *      gettok_state - gettok state block to use
 *      str - Writable buffer to tokenize. Note that gettok()
 *              is allowed to change the contents of this buffer.
 *      inc_null_final - If the line ends in whitespace instead of
 *              immediately hitting a NULL, and inc_null_final is TRUE,
 *              then a null final token is generated. Otherwise trailing
 *              whitespace is ignored.
 */
static void
gettok_init(GETTOK_STATE *gettok_state, char *buf, int inc_null_final)
{
        gettok_state->gtok_buf = gettok_state->gtok_cur_buf = buf;
        gettok_state->gtok_inc_null_final = inc_null_final;
        gettok_state->gtok_null_seen = 0;
}


/*
 * Locate the next token from the buffer.
 *
 * entry:
 *      gettok_state - State of gettok() operation. Initialized
 *              by gettok_init(), and passed to gettok().
 *
 * exit:
 *      If a token is found, gettok_state->gtok_last_token is filled in
 *      with the details and True (1) is returned. If no token is found,
 *      False (1) is returned, and the contents of
 *      gettok_state->gtok_last_token are undefined.
 *
 * note:
 *      - The token returned references the memory in gettok_state->gtok_buf.
 *              The caller should not modify the buffer until all such
 *              pointers have been discarded.
 *      - This routine will modify the contents of gettok_state->gtok_buf
 *              as necessary to remove quotes and eliminate escape
 *              (\)characters.
 */
static int
gettok(GETTOK_STATE *gettok_state)
{
        char    *str = gettok_state->gtok_cur_buf;
        char    *look;
        int     quote_ch = '\0';

        /* Skip leading whitespace */
        while (isspace(*str))
                str++;

        if (*str == '\0') {
                /*
                 * If user requested it, and there was whitespace at the
                 * end, then generate one last null token.
                 */
                if (gettok_state->gtok_inc_null_final &&
                    !gettok_state->gtok_null_seen) {
                        gettok_state->gtok_inc_null_final = 0;
                        gettok_state->gtok_null_seen = 1;
                        gettok_state->gtok_last_token.tok_str = str;
                        gettok_state->gtok_last_token.tok_len = 0;
                        gettok_state->gtok_last_token.tok_line_off =
                            str - gettok_state->gtok_buf;
                        return (1);
                }
                gettok_state->gtok_null_seen = 1;
                return (0);
        }

        /*
         * Read token: The standard delimiter is whitespace, but
         * we honor either single or double quotes. Also, we honor
         * backslash escapes.
         */
        gettok_state->gtok_last_token.tok_str = look = str;
        gettok_state->gtok_last_token.tok_line_off =
            look - gettok_state->gtok_buf;
        for (; *look; look++) {
                if (*look == quote_ch) {        /* Terminates active quote */
                        quote_ch = '\0';
                        continue;
                }

                if (quote_ch == '\0') {         /* No quote currently active */
                        if ((*look == '\'') || (*look == '"')) {
                                quote_ch = *look;       /* New active quote */
                                continue;
                        }
                        if (isspace(*look))
                                break;
                }

                /*
                 * The semantics of the backslash character depends on
                 * the quote style in use:
                 *      - Within single quotes, backslash is not
                 *              an escape character, and is taken literally.
                 *      - If outside of quotes, the backslash is an escape
                 *              character. The backslash is ignored and the
                 *              following character is taken literally, losing
                 *              any special properties it normally has.
                 *      - Within double quotes, backslash works like a
                 *              backslash escape within a C literal. Certain
                 *              escapes are recognized and replaced with their
                 *              special character. Any others are an error.
                 */
                if (*look == '\\') {
                        if (quote_ch == '\'') {
                                *str++ = *look;
                                continue;
                        }

                        look++;
                        if (*look == '\0') {    /* Esc applied to NULL term? */
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_ESCEOL));
                                /*NOTREACHED*/
                        }

                        if (quote_ch == '"') {
                                int ch = conv_translate_c_esc(&look);

                                if (ch == -1)
                                        elfedit_msg(ELFEDIT_MSG_ERR,
                                            MSG_INTL(MSG_ERR_BADCESC), *look);
                                *str++ = ch;
                                look--;         /* for() will advance by 1 */
                                continue;
                        }
                }

                if (look != str)
                        *str = *look;
                str++;
        }

        /* Don't allow unterminated quoted tokens */
        if (quote_ch != '\0')
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_UNTERMQUOTE),
                    quote_ch);

        gettok_state->gtok_last_token.tok_len = str -
            gettok_state->gtok_last_token.tok_str;
        gettok_state->gtok_null_seen = *look == '\0';
        if (!gettok_state->gtok_null_seen)
                look++;
        *str = '\0';
        gettok_state->gtok_cur_buf = look;

#ifdef DEBUG_GETTOK
        printf("GETTOK >");
        elfedit_str_to_c_literal(gettok_state->gtok_last_token.tok_str,
            elfedit_write);
        printf("< \tlen(%d) offset(%d)\n",
            gettok_state->gtok_last_token.tok_len,
            gettok_state->gtok_last_token.tok_line_off);
#endif

        return (1);
}


/*
 * Tokenize the user command string, and return a pointer to the
 * TOK_STATE buffer maintained by this function. That buffer contains
 * the tokenized strings.
 *
 * entry:
 *      user_cmd_str - String to tokenize
 *      len - # of characters in user_cmd_str to examine. If
 *              (len < 0), then the complete string is processed
 *              stopping with the NULL termination. Otherwise,
 *              processing stops after len characters, and any
 *              remaining characters are ignored.
 *      inc_null_final - If True, and if user_cmd_str has whitespace
 *              at the end following the last non-null token, then
 *              a final null token will be included. If False, null
 *              tokens are ignored.
 *
 * note:
 *      This routine returns pointers to internally allocated memory.
 *      The caller must not alter anything contained in the TOK_STATE
 *      buffer returned. Furthermore, the the contents of TOK_STATE
 *      are only valid until the next call to tokenize_user_cmd().
 */
static TOK_STATE *
tokenize_user_cmd(const char *user_cmd_str, size_t len, int inc_null_final)
{
#define INITIAL_TOK_ALLOC 5

        /*
         * As we parse the user command, we need temporary space to
         * hold the tokens. We do this by dynamically allocating a string
         * buffer and a token array, and doubling them as necessary. This
         * is a single threaded application, so static variables suffice.
         */
        static STRBUF str;
        static TOK_STATE tokst;

        GETTOK_STATE    gettok_state;
        size_t          n;

        /*
         * Make a copy we can modify. If (len == 0), take the entire
         * string. Otherwise limit it to the specified length.
         */
        tokst.tokst_cmd_len = strlen(user_cmd_str);
        if ((len > 0) && (len < tokst.tokst_cmd_len))
                tokst.tokst_cmd_len = len;
        tokst.tokst_cmd_len++;  /* Room for NULL termination */
        strbuf_ensure_size(&str, tokst.tokst_cmd_len);
        (void) strlcpy(str.buf, user_cmd_str, tokst.tokst_cmd_len);

        /* Trim off any newline character that might be present */
        if ((tokst.tokst_cmd_len > 1) &&
            (str.buf[tokst.tokst_cmd_len - 2] == '\n')) {
                tokst.tokst_cmd_len--;
                str.buf[tokst.tokst_cmd_len - 1] = '\0';
        }

        /* Tokenize the user command string into tok struct */
        gettok_init(&gettok_state, str.buf, inc_null_final);
        tokst.tokst_str_size = 0;       /* Space needed for token strings */
        for (tokst.tokst_cnt = 0; gettok(&gettok_state) != 0;
            tokst.tokst_cnt++) {
                /* If we need more room, expand the token buffer */
                if (tokst.tokst_cnt >= tokst.tokst_bufsize) {
                        n = (tokst.tokst_bufsize == 0) ?
                            INITIAL_TOK_ALLOC : (tokst.tokst_bufsize * 2);
                        tokst.tokst_buf = elfedit_realloc(
                            MSG_INTL(MSG_ALLOC_TOKBUF), tokst.tokst_buf,
                            n * sizeof (*tokst.tokst_buf));
                        tokst.tokst_bufsize = n;
                }
                tokst.tokst_str_size +=
                    gettok_state.gtok_last_token.tok_len + 1;
                tokst.tokst_buf[tokst.tokst_cnt] = gettok_state.gtok_last_token;
        }
        /* fold the command token to lowercase */
        if (tokst.tokst_cnt > 0) {
                char *s;

                for (s = tokst.tokst_buf[0].tok_str; *s; s++)
                        if (isupper(*s))
                                *s = tolower(*s);
        }

        return (&tokst);

#undef  INITIAL_TOK_ALLOC
}


/*
 * Parse the user command string, and put an entry for it at the end
 * of state.ucmd.
 */
static void
parse_user_cmd(const char *user_cmd_str)
{
        TOK_STATE       *tokst;
        char            *s;
        size_t          n;
        size_t          len;
        USER_CMD_T      *ucmd;
        elfeditGC_module_t *mod;
        elfeditGC_cmd_t *cmd;

        /*
         * Break it into tokens. If there are none, then it is
         * an empty command and is ignored.
         */
        tokst = tokenize_user_cmd(user_cmd_str, -1, 0);
        if (tokst->tokst_cnt == 0)
                return;

        /* Find the command. Won't return on error */
        cmd = elfedit_find_command(tokst->tokst_buf[0].tok_str, 1, &mod);

        /*
         * If there is no ELF file being edited, then only commands
         * from the sys: module are allowed.
         */
        if ((state.file.present == 0) &&
            (strcmp(mod->mod_name, MSG_ORIG(MSG_MOD_SYS)) != 0))
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_NOFILSYSONLY),
                    mod->mod_name, cmd->cmd_name[0]);


        /* Allocate, fill in, and insert a USER_CMD_T block */
        n = S_DROUND(sizeof (USER_CMD_T));
        ucmd = elfedit_malloc(MSG_INTL(MSG_ALLOC_UCMD),
            n + (sizeof (char *) * (tokst->tokst_cnt - 1)) +
            tokst->tokst_cmd_len + tokst->tokst_str_size);
        ucmd->ucmd_next = NULL;
        ucmd->ucmd_argc = tokst->tokst_cnt - 1;
        /*LINTED E_BAD_PTR_CAST_ALIGN*/
        ucmd->ucmd_argv = (const char **)(n + (char *)ucmd);
        ucmd->ucmd_orig_str = (char *)(ucmd->ucmd_argv + ucmd->ucmd_argc);
        (void) strncpy(ucmd->ucmd_orig_str, user_cmd_str, tokst->tokst_cmd_len);
        ucmd->ucmd_mod = mod;
        ucmd->ucmd_cmd = cmd;
        ucmd->ucmd_ostyle_set = 0;
        s = ucmd->ucmd_orig_str + tokst->tokst_cmd_len;
        for (n = 1; n < tokst->tokst_cnt; n++) {
                len = tokst->tokst_buf[n].tok_len + 1;
                ucmd->ucmd_argv[n - 1] = s;
                (void) strncpy(s, tokst->tokst_buf[n].tok_str, len);
                s += len;
        }
        if (state.ucmd.list == NULL) {
                state.ucmd.list = state.ucmd.tail = ucmd;
        } else {
                state.ucmd.tail->ucmd_next = ucmd;
                state.ucmd.tail = ucmd;
        }
        state.ucmd.n++;
}


/*
 * Copy infile to a new file with the name given by outfile.
 */
static void
create_outfile(const char *infile, const char *outfile)
{
        pid_t pid;
        int statloc;
        struct stat statbuf;


        pid = fork();
        switch (pid) {
        case -1:                        /* Unable to create process */
                {
                        int err = errno;
                        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTFORK),
                            strerror(err));
                }
                /*NOTREACHED*/
                return;

        case 0:
                (void) execl(MSG_ORIG(MSG_STR_BINCP),
                    MSG_ORIG(MSG_STR_BINCP), infile, outfile, NULL);
                /*
                 * exec() only returns on error. This is the child process,
                 * so we want to stay away from the usual error mechanism
                 * and handle things directly.
                 */
                {
                        int err = errno;
                        (void) fprintf(stderr, MSG_INTL(MSG_ERR_CNTEXEC),
                            MSG_ORIG(MSG_STR_ELFEDIT),
                            MSG_ORIG(MSG_STR_BINCP), strerror(err));
                }
                exit(1);
                /*NOTREACHED*/
        }

        /* This is the parent: Wait for the child to terminate */
        if (waitpid(pid, &statloc,  0) != pid) {
                int err = errno;
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTWAIT),
                    strerror(err));
        }
        /*
         * If the child failed, then terminate the process. There is no
         * need for an error message, because the child will have taken
         * care of that.
         */
        if (!WIFEXITED(statloc) || (WEXITSTATUS(statloc) != 0))
                exit(1);

        /* Make sure the copy allows user write access */
        if (stat(outfile, &statbuf) == -1) {
                int err = errno;
                (void) unlink(outfile);
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTSTAT),
                    outfile, strerror(err));
        }
        if ((statbuf.st_mode & S_IWUSR) == 0) {
                /* Only keep permission bits, and add user write */
                statbuf.st_mode |= S_IWUSR;
                statbuf.st_mode &= 07777;   /* Only keep the permission bits */
                if (chmod(outfile, statbuf.st_mode) == -1) {
                        int err = errno;
                        (void) unlink(outfile);
                        elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTCHMOD),
                            outfile, strerror(err));
                }
        }
}

/*
 * Given a module path string, determine how long the resulting path will
 * be when all % tokens have been expanded.
 *
 * entry:
 *      path - Path for which expanded length is desired
 *      origin_root - Root of $ORIGIN  tree containing running elfedit program
 *
 * exit:
 *      Returns the value strlen() will give for the expanded path.
 */
static size_t
modpath_strlen(const char *path, const char *origin_root)
{
        size_t len = 0;
        const char *s;

        s = path;
        len = 0;
        for (s = path; *s != '\0'; s++) {
                if (*s == '%') {
                        s++;
                        switch (*s) {
                        case 'i':       /* ISA of running elfedit */
                                len += strlen(isa_i_str);
                                break;
                        case 'I':       /* "" for 32-bit, same as %i for 64 */
                                len += strlen(isa_I_str);
                                break;
                        case 'o':       /* Insert default path */
                                len +=
                                    modpath_strlen(MSG_ORIG(MSG_STR_MODPATH),
                                    origin_root);
                                break;
                        case 'r':       /* root of tree with running elfedit */
                                len += strlen(origin_root);
                                break;

                        case '%':       /* %% is reduced to just '%' */
                                len++;
                                break;
                        default:        /* All other % codes are reserved */
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_BADPATHCODE), *s);
                                /*NOTREACHED*/
                                break;
                        }
                } else {        /* Non-% character passes straight through */
                        len++;
                }
        }

        return (len);
}


/*
 * Given a module path string, and a buffer large enough to hold the results,
 * fill the buffer with the expanded path.
 *
 * entry:
 *      path - Path for which expanded length is desired
 *      origin_root - Root of tree containing running elfedit program
 *      buf - Buffer to receive the result. buf must as large or larger
 *              than the value given by modpath_strlen().
 *
 * exit:
 *      Returns pointer to location following the last character
 *      written to buf. A NULL byte is written to that address.
 */
static char *
modpath_expand(const char *path, const char *origin_root, char *buf)
{
        size_t len;
        const char *cp_str;

        for (; *path != '\0'; path++) {
                if (*path == '%') {
                        path++;
                        cp_str = NULL;
                        switch (*path) {
                        case 'i':       /* ISA of running elfedit */
                                cp_str = isa_i_str;
                                break;
                        case 'I':       /* "" for 32-bit, same as %i for 64 */
                                cp_str = isa_I_str;
                                break;
                        case 'o':       /* Insert default path */
                                buf = modpath_expand(MSG_ORIG(MSG_STR_MODPATH),
                                    origin_root, buf);
                                break;
                        case 'r':
                                cp_str = origin_root;
                                break;
                        case '%':       /* %% is reduced to just '%' */
                                *buf++ = *path;
                                break;
                        default:        /* All other % codes are reserved */
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_BADPATHCODE), *path);
                                /*NOTREACHED*/
                                break;
                        }
                        if ((cp_str != NULL) && ((len = strlen(cp_str)) > 0)) {
                                bcopy(cp_str, buf, len);
                                buf += len;
                        }
                } else {        /* Non-% character passes straight through */
                        *buf++ = *path;
                }
        }

        *buf = '\0';
        return (buf);
}


/*
 * Establish the module search path: state.modpath
 *
 * The path used comes from the following sources, taking the first
 * one that has a value, and ignoring any others:
 *
 *      - ELFEDIT_PATH environment variable
 *      - -L command line argument
 *      - Default value
 *
 * entry:
 *      path - NULL, or the value of the -L command line argument
 *
 * exit:
 *      state.modpath has been filled in
 */
static void
establish_modpath(const char *cmdline_path)
{
        char origin_root[PATH_MAX + 1]; /* Where elfedit binary is */
        const char      *path;          /* Initial path */
        char            *expath;        /* Expanded path */
        size_t          len;
        char            *src, *dst;

        path = getenv(MSG_ORIG(MSG_STR_ENVVAR));
        if (path == NULL)
                path = cmdline_path;
        if (path == NULL)
                path = MSG_ORIG(MSG_STR_MODPATH);


        /*
         * Root of tree containing running for running program. 32-bit elfedit
         * is installed in /usr/bin, and 64-bit elfedit is one level lower
         * in an ISA-specific subdirectory. So, we find the root by
         * getting the $ORGIN of the current running program, and trimming
         * off the last 2 (32-bit) or 3 (64-bit) directories.
         *
         * On a standard system, this will simply yield '/'. However,
         * doing it this way allows us to run elfedit from a proto area,
         * and pick up modules from the same proto area instead of those
         * installed on the system.
         */
        if (dlinfo(RTLD_SELF, RTLD_DI_ORIGIN, &origin_root) == -1)
                elfedit_msg(ELFEDIT_MSG_ERR, MSG_INTL(MSG_ERR_CNTGETORIGIN));
        len = (sizeof (char *) == 8) ? 3 : 2;
        src = origin_root + strlen(origin_root);
        while ((src > origin_root) && (len > 0)) {
                if (*(src - 1) == '/')
                        len--;
                src--;
        }
        *src = '\0';


        /*
         * Calculate space needed to hold expanded path. Note that
         * this assumes that MSG_STR_MODPATH will never contain a '%o'
         * code, and so, the expansion is not recursive. The codes allowed
         * are:
         *      %i - ISA of running elfedit (sparc, sparcv9, etc)
         *      %I - 64-bit ISA: Same as %i for 64-bit versions of elfedit,
         *              but yields empty string for 32-bit ISAs.
         *      %o - The original (default) path.
         *      %r - Root of tree holding elfedit program.
         *      %% - A single %
         *
         * A % followed by anything else is an error. This allows us to
         * add new codes in the future without backward compatability issues.
         */
        len = modpath_strlen(path, origin_root);

        expath = elfedit_malloc(MSG_INTL(MSG_ALLOC_EXPATH), len + 1);
        (void) modpath_expand(path, origin_root, expath);

        /*
         * Count path segments, eliminate extra '/', and replace ':'
         * with NULL.
         */
        state.modpath.n = 1;
        for (src = dst = expath; *src; src++) {
                if (*src == '/') {
                        switch (*(src + 1)) {
                        case '/':
                        case ':':
                        case '\0':
                                continue;
                        }
                }
                if (*src == ':') {
                        state.modpath.n++;
                        *dst = '\0';
                } else if (src != dst) {
                        *dst = *src;
                }
                dst++;
        }
        if (src != dst)
                *dst = '\0';

        state.modpath.seg = elfedit_malloc(MSG_INTL(MSG_ALLOC_PATHARR),
            sizeof (state.modpath.seg[0]) * state.modpath.n);

        src = expath;
        for (len = 0; len < state.modpath.n; len++) {
                if (*src == '\0') {
                        state.modpath.seg[len] = MSG_ORIG(MSG_STR_DOT);
                        src++;
                } else {
                        state.modpath.seg[len] = src;
                        src += strlen(src) + 1;
                }
        }
}

/*
 * When interactive (reading commands from a tty), we catch
 * SIGINT in order to restart the outer command loop.
 */
/*ARGSUSED*/
static void
sigint_handler(int sig, siginfo_t *sip, void *ucp)
{
        /* Jump to the outer loop to resume */
        if (state.msg_jbuf.active) {
                state.msg_jbuf.active = 0;
                siglongjmp(state.msg_jbuf.env, 1);
        }
}


static void
usage(int full)
{
        elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_BRIEF));
        if (full) {
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL1));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL2));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL3));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL4));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL5));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL6));
                elfedit_msg(ELFEDIT_MSG_USAGE, MSG_INTL(MSG_USAGE_DETAIL_LAST));
        }
        elfedit_exit(2);
}


/*
 * In order to complete commands, we need to know about them,
 * which means that we need to force all the modules to be
 * loaded. This is a relatively expensive operation, so we use
 * this function, which avoids doing it more than once in a session.
 */
static void
elfedit_cpl_load_modules(void)
{
        static int loaded;

        if (!loaded) {
                elfedit_load_modpath();
                loaded = 1;     /* Don't do it again */
        }
}

/*
 * Compare the token to the given string, and if they share a common
 * initial sequence, add the tail of string to the tecla command completion
 * buffer:
 *
 * entry:
 *      cpldata - Current completion state
 *      str - String to match against token
 *      casefold - True to allow case insensitive completion, False
 *              if case must match exactly.
 */
void
elfedit_cpl_match(void *cpldata, const char *str, int casefold)
{
        ELFEDIT_CPL_STATE *cstate = (ELFEDIT_CPL_STATE *) cpldata;
        const char      *cont_suffix;
        const char      *type_suffix;

        /*
         * Reasons to return immediately:
         *      - NULL strings have no completion value
         *      - The string is shorter than the existing item being completed
         */
        if ((str == NULL) || (*str == '\0') ||
            ((cstate->ecpl_token_len != 0) &&
            ((strlen(str) < cstate->ecpl_token_len))))
                return;

        /* If the string does not share the existing prefix, don't use it */
        if (casefold) {
                if (strncasecmp(cstate->ecpl_token_str, str,
                    cstate->ecpl_token_len) != 0)
                        return;
        } else {
                if (strncmp(cstate->ecpl_token_str, str,
                    cstate->ecpl_token_len) != 0)
                        return;
        }

        if (cstate->ecpl_add_mod_colon) {
                cont_suffix = type_suffix = MSG_ORIG(MSG_STR_COLON);
        } else {
                cont_suffix = MSG_ORIG(MSG_STR_SPACE);
                type_suffix = NULL;
        }
        (void) cpl_add_completion(cstate->ecpl_cpl, cstate->ecpl_line,
            cstate->ecpl_word_start, cstate->ecpl_word_end,
            str + cstate->ecpl_token_len, type_suffix, cont_suffix);

}


/*
 * Convenience wrapper on elfedit_cpl_match(): Format an unsigned
 * 32-bit integer as a string and enter the result for command completion.
 */
void
elfedit_cpl_ndx(void *cpldata, uint_t ndx)
{
        Conv_inv_buf_t  buf;

        (void) snprintf(buf.buf, sizeof (buf.buf),
            MSG_ORIG(MSG_FMT_WORDVAL), ndx);
        elfedit_cpl_match(cpldata, buf.buf, 0);
}


/*
 * Compare the token to the names of the commands from the given module,
 * and if they share a common initial sequence, add the tail of string
 * to the tecla command completion buffer:
 *
 * entry:
 *      tok_buf - Token user has entered
 *      tok_len - strlen(tok_buf)
 *      mod - Module definition from which commands should be matched
 *      cpl, line, word_start, word_end, cont_suffix - As documented
 *              for gl_get_line() and cpl_add_completion.
 */
static void
match_module_cmds(ELFEDIT_CPL_STATE *cstate, elfeditGC_module_t *mod)
{
        elfeditGC_cmd_t *cmd;
        const char **cmd_name;

        for (cmd = mod->mod_cmds; cmd->cmd_func != NULL; cmd++)
                for (cmd_name = cmd->cmd_name; *cmd_name; cmd_name++)
                        elfedit_cpl_match(cstate, *cmd_name, 1);
}


/*
 * Compare the token to the known module names, and add those that
 * match to the list of alternatives via elfedit_cpl_match().
 *
 * entry:
 *      load_all_modules - If True, causes all modules to be loaded
 *              before processing is done. If False, only the modules
 *              currently seen will be used.
 */
void
elfedit_cpl_module(void *cpldata, int load_all_modules)
{
        ELFEDIT_CPL_STATE       *cstate = (ELFEDIT_CPL_STATE *) cpldata;
        MODLIST_T               *modlist;

        if (load_all_modules)
                elfedit_cpl_load_modules();

        for (modlist = state.modlist; modlist != NULL;
            modlist = modlist->ml_next) {
                elfedit_cpl_match(cstate, modlist->ml_mod->mod_name, 1);
        }
}


/*
 * Compare the token to all the known commands, and add those that
 * match to the list of alternatives.
 *
 * note:
 *      This routine will force modules to be loaded as necessary to
 *      obtain the names it needs to match.
 */
void
elfedit_cpl_command(void *cpldata)
{
        ELFEDIT_CPL_STATE       *cstate = (ELFEDIT_CPL_STATE *) cpldata;
        ELFEDIT_CPL_STATE       colon_state;
        const char              *colon_pos;
        MODLIST_T               *modlist;
        MODLIST_T               *insdef;
        char                    buf[128];

        /*
         * Is there a colon in the command? If so, locate its offset within
         * the raw input line.
         */
        for (colon_pos = cstate->ecpl_token_str;
            *colon_pos && (*colon_pos != ':'); colon_pos++)
                ;

        /*
         * If no colon was seen, then we are completing a module name,
         * or one of the commands from 'sys:'
         */
        if (*colon_pos == '\0') {
                /*
                 * Setting cstate->add_mod_colon tells elfedit_cpl_match()
                 * to add an implicit ':' to the names it matches. We use it
                 * here so the user doesn't have to enter the ':' manually.
                 * Hiding this in the opaque state instead of making it
                 * an argument to that function gives us the ability to
                 * change it later without breaking the published interface.
                 */
                cstate->ecpl_add_mod_colon = 1;
                elfedit_cpl_module(cpldata, 1);
                cstate->ecpl_add_mod_colon = 0;

                /* Add bare (no sys: prefix) commands from the sys: module */
                match_module_cmds(cstate,
                    elfedit_load_module(MSG_ORIG(MSG_MOD_SYS), 1, 0));

                return;
        }

        /*
         * A colon was seen, so we have a module name. Extract the name,
         * substituting 'sys' for the case where the given name is empty.
         */
        if (colon_pos == 0)
                (void) strlcpy(buf, MSG_ORIG(MSG_MOD_SYS), sizeof (buf));
        else
                elfedit_strnbcpy(buf, cstate->ecpl_token_str,
                    colon_pos - cstate->ecpl_token_str, sizeof (buf));

        /*
         * Locate the module. If it isn't already loaded, make an explicit
         * attempt to load it and try again. If a module definition is
         * obtained, process the commands it supplies.
         */
        modlist = module_loaded(buf, &insdef);
        if (modlist == NULL) {
                (void) elfedit_load_module(buf, 0, 0);
                modlist = module_loaded(buf, &insdef);
        }
        if (modlist != NULL) {
                /*
                 * Make a copy of the cstate, and adjust the line and
                 * token so that the new one starts just past the colon
                 * character. We know that the colon exists because
                 * of the preceeding test that found it. Therefore, we do
                 * not need to test against running off the end of the
                 * string here.
                 */
                colon_state = *cstate;
                while (colon_state.ecpl_line[colon_state.ecpl_word_start] !=
                    ':')
                        colon_state.ecpl_word_start++;
                while (*colon_state.ecpl_token_str != ':') {
                        colon_state.ecpl_token_str++;
                        colon_state.ecpl_token_len--;
                }
                /* Skip past the ':' character */
                colon_state.ecpl_word_start++;
                colon_state.ecpl_token_str++;
                colon_state.ecpl_token_len--;

                match_module_cmds(&colon_state, modlist->ml_mod);
        }
}


/*
 * Command completion function for use with libtacla.
 */
/*ARGSUSED1*/
static int
cmd_match_fcn(WordCompletion *cpl, void *data, const char *line, int word_end)
{
        const char              *argv[ELFEDIT_MAXCPLARGS];
        ELFEDIT_CPL_STATE       cstate;
        TOK_STATE               *tokst;
        int                     ndx;
        int                     i;
        elfeditGC_module_t      *mod;
        elfeditGC_cmd_t         *cmd;
        int                     num_opt;
        int                     opt_term_seen;
        int                     skip_one;
        elfedit_cmd_optarg_t    *optarg;
        elfedit_optarg_item_t   item;
        int                     ostyle_ndx = -1;

        /*
         * For debugging, enable the following block. It tells the tecla
         * library that the program using is going to write to stdout.
         * It will put the tty back into normal mode, and it will cause
         * tecla to redraw the current input line when it gets control back.
         */
#ifdef DEBUG_CMD_MATCH
        gl_normal_io(state.input.gl);
#endif

        /*
         * Tokenize the line up through word_end. The last token in
         * the list is the one requiring completion.
         */
        tokst = tokenize_user_cmd(line, word_end, 1);
        if (tokst->tokst_cnt == 0)
                return (0);

        /* Set up the cstate block, containing the completion state */
        ndx = tokst->tokst_cnt - 1;     /* Index of token to complete */
        cstate.ecpl_cpl = cpl;
        cstate.ecpl_line = line;
        cstate.ecpl_word_start = tokst->tokst_buf[ndx].tok_line_off;
        cstate.ecpl_word_end = word_end;
        cstate.ecpl_add_mod_colon = 0;
        cstate.ecpl_token_str = tokst->tokst_buf[ndx].tok_str;
        cstate.ecpl_token_len = tokst->tokst_buf[ndx].tok_len;

        /*
         * If there is only one token, then we are completing the
         * command itself.
         */
        if (ndx == 0) {
                elfedit_cpl_command(&cstate);
                return (0);
        }

        /*
         * There is more than one token. Use the first one to
         * locate the definition for the command. If we don't have
         * a definition for the command, then there's nothing more
         * we can do.
         */
        cmd = elfedit_find_command(tokst->tokst_buf[0].tok_str, 0, &mod);
        if (cmd == NULL)
                return (0);

        /*
         * Since we know the command, give them a quick usage message.
         * It may be that they just need a quick reminder about the form
         * of the command and the options.
         */
        (void) gl_normal_io(state.input.gl);
        elfedit_printf(MSG_INTL(MSG_USAGE_CMD),
            elfedit_format_command_usage(mod, cmd, NULL, 0));


        /*
         * We have a generous setting for ELFEDIT_MAXCPLARGS, so there
         * should always be plenty of room. If there's not room, we
         * can't proceed.
         */
        if (ndx >= ELFEDIT_MAXCPLARGS)
                return (0);

        /*
         * Put pointers to the tokens into argv, and determine how
         * many of the tokens are optional arguments.
         *
         * We consider the final optional argument to be the rightmost
         * argument that starts with a '-'. If a '--' is seen, then
         * we stop there, and any argument that follows is a plain argument
         * (even if it starts with '-').
         *
         * We look for an inherited '-o' option, because we are willing
         * to supply command completion for these values.
         */
        num_opt = 0;
        opt_term_seen = 0;
        skip_one = 0;
        for (i = 0; i < ndx; i++) {
                argv[i] = tokst->tokst_buf[i + 1].tok_str;
                if (opt_term_seen || skip_one) {
                        skip_one = 0;
                        continue;
                }
                skip_one = 0;
                ostyle_ndx = -1;
                if ((strcmp(argv[i], MSG_ORIG(MSG_STR_MINUS_MINUS)) == 0) ||
                    (*argv[i] != '-')) {
                        opt_term_seen = 1;
                        continue;
                }
                num_opt = i + 1;
                /*
                 * If it is a recognised ELFEDIT_CMDOA_F_VALUE option,
                 * then the item following it is the associated value.
                 * Check for this and skip the value.
                 *
                 * At the same time, look for STDOA_OPT_O inherited
                 * options. We want to identify the index of any such
                 * item. Although the option is simply "-o", we are willing
                 * to treat any option that starts with "-o" as a potential
                 * STDOA_OPT_O. This lets us to command completion for things
                 * like "-onum", and is otherwise harmless, the only cost
                 * being a few additional strcmps by the cpl code.
                 */
                if ((optarg = cmd->cmd_opt) == NULL)
                        continue;
                while (optarg->oa_name != NULL) {
                        int is_ostyle_optarg =
                            (optarg->oa_flags & ELFEDIT_CMDOA_F_INHERIT) &&
                            (optarg->oa_name == ELFEDIT_STDOA_OPT_O);

                        elfedit_next_optarg(&optarg, &item);
                        if (item.oai_flags & ELFEDIT_CMDOA_F_VALUE) {
                                if (is_ostyle_optarg && (strncmp(argv[i],
                                    MSG_ORIG(MSG_STR_MINUS_O), 2) == 0))
                                        ostyle_ndx = i + 1;

                                if (strcmp(item.oai_name, argv[i]) == 0) {
                                        num_opt = i + 2;
                                        skip_one = 1;
                                        break;
                                }
                                /*
                                 * If it didn't match "-o" exactly, but it is
                                 * ostyle_ndx, then it is a potential combined
                                 * STDOA_OPT_O, as discussed above. It counts
                                 * as a single argument.
                                 */
                                if (ostyle_ndx == ndx)
                                        break;
                        }
                }
        }

#ifdef DEBUG_CMD_MATCH
        (void) printf("NDX(%d) NUM_OPT(%d) ostyle_ndx(%d)\n", ndx, num_opt,
            ostyle_ndx);
#endif

        if (ostyle_ndx != -1) {
                /*
                 * If ostyle_ndx is one less than ndx, and ndx is
                 * the same as num_opt, then we have a definitive
                 * STDOA_OPT_O inherited outstyle option. We supply
                 * the value strings, and are done.
                 */
                if ((ostyle_ndx == (ndx - 1)) && (ndx == num_opt)) {
                        elfedit_cpl_atoconst(&cstate, ELFEDIT_CONST_OUTSTYLE);
                        return (0);
                }

                /*
                 * If ostyle is the same as ndx, then we have an option
                 * staring with "-o" that may end up being a STDOA_OPT_O,
                 * and we are still inside that token. In this case, we
                 * supply completion strings that include the leading
                 * "-o" followed by the values, without a space
                 * (i.e. "-onum"). We then fall through, allowing any
                 * other options starting with "-o" to be added
                 * below. elfedit_cpl_match() will throw out the incorrect
                 * options, so it is harmless to add these extra items in
                 * the worst case, and useful otherwise.
                 */
                if (ostyle_ndx == ndx)
                        elfedit_cpl_atoconst(&cstate,
                            ELFEDIT_CONST_OUTSTYLE_MO);
        }

        /*
         * If (ndx <= num_opt), then the token needing completion
         * is an option. If the leading '-' is there, then we should fill
         * in all of the option alternatives. If anything follows the '-'
         * though, we assume that the user has already figured out what
         * option to use, and we leave well enough alone.
         *
         * Note that we are intentionally ignoring a related case
         * where supplying option strings would be legal: In the case
         * where we are one past the last option (ndx == (num_opt + 1)),
         * and the current option is an empty string, the argument can
         * be either a plain argument or an option --- the user needs to
         * enter the next character before we can tell. It would be
         * OK to enter the option strings in this case. However, consider
         * what happens when the first plain argument to the command does
         * not provide any command completion (e.g. it is a plain integer).
         * In this case, tecla will see that all the alternatives start
         * with '-', and will insert a '-' into the input. If the user
         * intends the next argument to be plain, they will have to delete
         * this '-', which is annoying. Worse than that, they may be confused
         * by it, and think that the plain argument is not allowed there.
         * The best solution is to not supply option strings unless the
         * user first enters the '-'.
         */
        if ((ndx <= num_opt) && (argv[ndx - 1][0] == '-')) {
                if ((optarg = cmd->cmd_opt) != NULL) {
                        while (optarg->oa_name != NULL) {
                                elfedit_next_optarg(&optarg, &item);
                                elfedit_cpl_match(&cstate, item.oai_name, 1);
                        }
                }
                return (0);
        }

        /*
         * At this point we know that ndx and num_opt are not equal.
         * If num_opt is larger than ndx, then we have an ELFEDIT_CMDOA_F_VALUE
         * argument at the end, and the following value has not been entered.
         *
         * If ndx is greater than num_opt, it means that we are looking
         * at a plain argument (or in the case where (ndx == (num_opt + 1)),
         * a *potential* plain argument.
         *
         * If the command has a completion function registered, then we
         * hand off the remaining work to it. The cmd_cplfunc field is
         * the generic definition. We need to cast it to the type that matches
         * the proper ELFCLASS before calling it.
         */
        if (state.elf.elfclass == ELFCLASS32) {
                elfedit32_cmdcpl_func_t *cmdcpl_func =
                    (elfedit32_cmdcpl_func_t *)cmd->cmd_cplfunc;

                if (cmdcpl_func != NULL)
                        (* cmdcpl_func)(state.elf.obj_state.s32,
                            &cstate, ndx, argv, num_opt);
        } else {
                elfedit64_cmdcpl_func_t *cmdcpl_func =
                    (elfedit64_cmdcpl_func_t *)cmd->cmd_cplfunc;

                if (cmdcpl_func != NULL)
                        (* cmdcpl_func)(state.elf.obj_state.s64,
                            &cstate, ndx, argv, num_opt);
        }

        return (0);
}


/*
 * Read a line of input from stdin, and return pointer to it.
 *
 * This routine uses a private buffer, so the contents of the returned
 * string are only good until the next call.
 */
static const char *
read_cmd(void)
{
        char *s;

        if (state.input.full_tty) {
                state.input.in_tecla = TRUE;
                s = gl_get_line(state.input.gl,
                    MSG_ORIG(MSG_STR_PROMPT), NULL, -1);
                state.input.in_tecla = FALSE;
                /*
                 * gl_get_line() returns NULL for EOF or for error. EOF is fine,
                 * but we need to catch and report anything else. Since
                 * reading from stdin is critical to our operation, an
                 * error implies that we cannot recover and must exit.
                 */
                if ((s == NULL) &&
                    (gl_return_status(state.input.gl) == GLR_ERROR)) {
                        elfedit_msg(ELFEDIT_MSG_FATAL, MSG_INTL(MSG_ERR_GLREAD),
                            gl_error_message(state.input.gl, NULL, 0));
                }
        } else {
                /*
                 * This should be a dynamically sized buffer, but for now,
                 * I'm going to take a simpler path.
                 */
                static char cmd_buf[ELFEDIT_MAXCMD + 1];

                s = fgets(cmd_buf, sizeof (cmd_buf), stdin);
        }

        /* Return user string, or 'quit' on EOF */
        return (s ? s : MSG_ORIG(MSG_SYS_CMD_QUIT));
}

int
main(int argc, char **argv, char **envp)
{
        /*
         * Note: This function can use setjmp()/longjmp() which does
         * not preserve the values of auto/register variables. Hence,
         * variables that need their values preserved across a jump must
         * be marked volatile, or must not be auto/register.
         *
         * Volatile can be messy, because it requires explictly casting
         * away the attribute when passing it to functions, or declaring
         * those functions with the attribute as well. In a single threaded
         * program like this one, an easier approach is to make things
         * static. That can be done here, or by putting things in the
         * 'state' structure.
         */

        int             c, i;
        int             num_batch = 0;
        char            **batch_list = NULL;
        const char      *modpath = NULL;

        /*
         * Always have liblddb display unclipped section names.
         * This global is exported by liblddb, and declared in debug.h.
         */
        dbg_desc->d_extra |= DBG_E_LONG;

        opterr = 0;
        while ((c = getopt(argc, argv, MSG_ORIG(MSG_STR_OPTIONS))) != EOF) {
                switch (c) {
                case 'a':
                        state.flags |= ELFEDIT_F_AUTOPRINT;
                        break;

                case 'd':
                        state.flags |= ELFEDIT_F_DEBUG;
                        break;

                case 'e':
                        /*
                         * Delay parsing the -e options until after the call to
                         * conv_check_native() so that we won't bother loading
                         * modules of the wrong class.
                         */
                        if (batch_list == NULL)
                                batch_list = elfedit_malloc(
                                    MSG_INTL(MSG_ALLOC_BATCHLST),
                                    sizeof (*batch_list) * (argc - 1));
                        batch_list[num_batch++] = optarg;
                        break;

                case 'L':
                        modpath = optarg;
                        break;

                case 'o':
                        if (elfedit_atooutstyle(optarg, &state.outstyle) == 0)
                                usage(1);
                        break;

                case 'r':
                        state.flags |= ELFEDIT_F_READONLY;
                        break;

                case '?':
                        usage(1);
                }
        }

        /*
         * We allow 0, 1, or 2 files:
         *
         * The no-file case is an extremely limited mode, in which the
         * only commands allowed to execute come from the sys: module.
         * This mode exists primarily to allow easy access to the help
         * facility.
         *
         * To get full access to elfedit's capablities, there must
         * be an input file. If this is not a readonly
         * session, then an optional second output file is allowed.
         *
         * In the case where two files are given and the session is
         * readonly, use a full usage message, because the simple
         * one isn't enough for the user to understand their error.
         * Otherwise, the simple usage message suffices.
         */
        argc = argc - optind;
        if ((argc == 2) && (state.flags & ELFEDIT_F_READONLY))
                usage(1);
        if (argc > 2)
                usage(0);

        state.file.present = (argc != 0);

        /*
         * If we have a file to edit, and unless told otherwise by the
         * caller, we try to run the 64-bit version of this program
         * when the system is capable of it. If that fails, then we
         * continue on with the currently running version.
         *
         * To force 32-bit execution on a 64-bit host, set the
         * LD_NOEXEC_64 environment variable to a non-empty value.
         *
         * There is no reason to bother with this if in "no file" mode.
         */
        if (state.file.present != 0)
                (void) conv_check_native(argv, envp);

        elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_VERSION),
            (sizeof (char *) == 8) ? 64 : 32);

        /*
         * Put a module definition for the builtin system module on the
         * module list. We know it starts out empty, so we do not have
         * to go through a more general insertion process than this.
         */
        state.modlist = elfedit_sys_init(ELFEDIT_VER_CURRENT);

        /* Establish the search path for loadable modules */
        establish_modpath(modpath);

        /*
         * Now that we are running the final version of this program,
         * deal with the input/output file(s).
         */
        if (state.file.present == 0) {
                /*
                 * This is arbitrary --- we simply need to be able to
                 * load modules so that we can access their help strings
                 * and command completion functions. Without a file, we
                 * will refuse to call commands from any module other
                 * than sys. Those commands have been written to be aware
                 * of the case where there is no input file, and are
                 * therefore safe to run.
                 */
                state.elf.elfclass = ELFCLASS32;
                elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_NOFILE));

        } else {
                state.file.infile = argv[optind];
                if (argc == 1) {
                        state.file.outfile = state.file.infile;
                        if (state.flags & ELFEDIT_F_READONLY)
                                elfedit_msg(ELFEDIT_MSG_DEBUG,
                                    MSG_INTL(MSG_DEBUG_READONLY));
                        else
                                elfedit_msg(ELFEDIT_MSG_DEBUG,
                                    MSG_INTL(MSG_DEBUG_INPLACEWARN),
                                    state.file.infile);
                } else {
                        state.file.outfile = argv[optind + 1];
                        create_outfile(state.file.infile, state.file.outfile);
                        elfedit_msg(ELFEDIT_MSG_DEBUG,
                            MSG_INTL(MSG_DEBUG_CPFILE),
                            state.file.infile, state.file.outfile);
                        /*
                         * We are editing a copy of the original file that we
                         * just created. If we should exit before the edits are
                         * updated, then we want to unlink this copy so that we
                         * don't leave junk lying around. Once an update
                         * succeeds however, we'll leave it in place even
                         * if an error occurs afterwards.
                         */
                        state.file.unlink_on_exit = 1;
                        optind++;       /* Edit copy instead of the original */
                }

                init_obj_state(state.file.outfile);
        }


        /*
         * Process commands.
         *
         * If any -e options were used, then do them and
         * immediately exit. On error, exit immediately without
         * updating the target ELF file. On success, the 'write'
         * and 'quit' commands are implicit in this mode.
         *
         * If no -e options are used, read commands from stdin.
         * quit must be explicitly used. Exit is implicit on EOF.
         * If stdin is a tty, then errors do not cause the editor
         * to terminate. Rather, the error message is printed, and the
         * user prompted to continue.
         */
        if (batch_list != NULL) {       /* -e was used */
                /* Compile the commands */
                for (i = 0; i < num_batch; i++)
                        parse_user_cmd(batch_list[i]);
                free(batch_list);

                /*
                 * 'write' and 'quit' are implicit in this mode.
                 * Add them as well.
                 */
                if ((state.flags & ELFEDIT_F_READONLY) == 0)
                        parse_user_cmd(MSG_ORIG(MSG_SYS_CMD_WRITE));
                parse_user_cmd(MSG_ORIG(MSG_SYS_CMD_QUIT));

                /* And run them. This won't return, thanks to the 'quit' */
                dispatch_user_cmds();
        } else {
                state.input.is_tty = isatty(fileno(stdin));
                state.input.full_tty = state.input.is_tty &&
                    isatty(fileno(stdout));

                if (state.input.full_tty) {
                        struct sigaction act;

                        act.sa_sigaction = sigint_handler;
                        (void) sigemptyset(&act.sa_mask);
                        act.sa_flags = 0;
                        if (sigaction(SIGINT, &act, NULL) == -1) {
                                int err = errno;
                                elfedit_msg(ELFEDIT_MSG_ERR,
                                    MSG_INTL(MSG_ERR_SIGACTION), strerror(err));
                        }
                        /*
                         * If pager process exits before we are done
                         * writing, we can see SIGPIPE. Prevent it
                         * from killing the process.
                         */
                        (void) sigignore(SIGPIPE);

                        /* Open tecla handle for command line editing */
                        state.input.gl = new_GetLine(ELFEDIT_MAXCMD,
                            ELFEDIT_MAXHIST);
                        /* Register our command completion function */
                        (void) gl_customize_completion(state.input.gl,
                            NULL, cmd_match_fcn);

                        /*
                         * Make autoprint the default for interactive
                         * sessions.
                         */
                        state.flags |= ELFEDIT_F_AUTOPRINT;
                }
                for (;;) {
                        /*
                         * If this is an interactive session, then use
                         * sigsetjmp()/siglongjmp() to recover from bad
                         * commands and keep going. A non-0 return from
                         * sigsetjmp() means that an error just occurred.
                         * In that case, we simply restart this loop.
                         */
                        if (state.input.is_tty) {
                                if (sigsetjmp(state.msg_jbuf.env, 1) != 0) {
                                        if (state.input.full_tty)
                                                gl_abandon_line(state.input.gl);
                                        continue;
                                }
                                state.msg_jbuf.active = TRUE;
                        }

                        /*
                         * Force all output out before each command.
                         * This is a no-OP when a tty is in use, but
                         * in a pipeline, it ensures that the block
                         * mode buffering doesn't delay output past
                         * the completion of each command.
                         *
                         * If we didn't do this, the output would eventually
                         * arrive at its destination, but the lag can be
                         * annoying when you pipe the output into a tool
                         * that displays the results in real time.
                         */
                        (void) fflush(stdout);
                        (void) fflush(stderr);

                        parse_user_cmd(read_cmd());
                        dispatch_user_cmds();
                        state.msg_jbuf.active = FALSE;
                }
        }


        /*NOTREACHED*/
        return (0);
}