fix regression from a745c4bfc8a9b5db4e48387170da0dc1d39e3abe

[uclibc-ng.git] / utils / ldconfig.c

/*
 * ldconfig - update shared library symlinks
 *
 * usage: ldconfig [-DvqnNX] [-f conf] [-C cache] [-r root] dir ...
 *        ldconfig -l [-Dv] lib ...
 *        ldconfig -p
 *        -D: debug mode, don't update links
 *        -v: verbose mode, print things as we go
 *        -q: quiet mode, don't print warnings
 *        -n: don't process standard directories
 *        -N: don't update the library cache
 *        -X: don't update the library links
 *        -l: library mode, manually link libraries
 *        -p: print the current library cache
 *        -f conf: use conf instead of /etc/ld.so.conf
 *        -C cache: use cache instead of /etc/ld.so.cache
 *        -r root: first, do a chroot to the indicated directory
 *        dir ...: directories to process
 *        lib ...: libraries to link
 *
 * Copyright 1994-2000 David Engel and Mitch D'Souza
 *
 * This program may be used for any purpose as long as this
 * copyright notice is kept.
 *
 * 2005/09/16: Dan Howell (modified for cross-development)
 */

#include "porting.h"

#define BUFFER_SIZE 4096

struct exec {
        unsigned long a_info;   /* Use macros N_MAGIC, etc for access */
        unsigned a_text;        /* length of text, in bytes */
        unsigned a_data;        /* length of data, in bytes */
        unsigned a_bss;         /* length of uninitialized data area for file, in bytes */
        unsigned a_syms;        /* length of symbol table data in file, in bytes */
        unsigned a_entry;       /* start address */
        unsigned a_trsize;      /* length of relocation info for text, in bytes */
        unsigned a_drsize;      /* length of relocation info for data, in bytes */
};

#if !defined (N_MAGIC)
#define N_MAGIC(exec) ((exec).a_info & 0xffff)
#endif
#define N_MAGIC_SWAP(exec) (bswap_32((exec).a_info) & 0xffff)
/* Code indicating object file or impure executable.  */
#define OMAGIC 0407
/* Code indicating pure executable.  */
#define NMAGIC 0410
/* Code indicating demand-paged executable.  */
#define ZMAGIC 0413
/* This indicates a demand-paged executable with the header in the text.
   The first page is unmapped to help trap NULL pointer references */
#define QMAGIC 0314
/* Code indicating core file.  */
#define CMAGIC 0421

char *prog = NULL;
int debug = 0;                  /* debug mode */
int verbose = 0;                /* verbose mode */
int libmode = 0;                /* library mode */
int nolinks = 0;                /* don't update links */
int nocache = 0;                /* don't build cache */
void cache_print(void);
void cache_write(void);
void cache_dolib(const char *dir, const char *so, int libtype);
#ifdef __LDSO_CACHE_SUPPORT__
char *conffile = LDSO_CONF;     /* default conf file */
char *cachefile = LDSO_CACHE;   /* default cache file */
#endif
char *chroot_dir = NULL;
int byteswap = 0;

struct needed_tab {
        char *soname;
        int type;
};

struct needed_tab needed_tab[] = {
        {"libc.so.0", LIB_ELF_LIBC0},
        {"libm.so.0", LIB_ELF_LIBC0},
        {"libdl.so.0", LIB_ELF_LIBC0},
        {"libc.so.5", LIB_ELF_LIBC5},
        {"libm.so.5", LIB_ELF_LIBC5},
        {"libdl.so.1", LIB_ELF_LIBC5},
        {"libc.so.6", LIB_ELF_LIBC6},
        {"libm.so.6", LIB_ELF_LIBC6},
        {"libdl.so.2", LIB_ELF_LIBC6},
        {NULL, LIB_ELF}
};

extern char *chroot_realpath(const char *chroot, const char *path,
                             char resolved_path[]);

#if defined __UCLIBC_STATIC_LDCONFIG__ || !defined __UCLIBC_HAS_BSD_ERR__
/* These two are used internally -- you shouldn't need to use them */
static void verror_msg(const char *s, va_list p)
{
        fflush(stdout);
        fprintf(stderr, "%s: ", prog);
        vfprintf(stderr, s, p);
}

static void warnx(const char *s, ...)
{
        va_list p;

        va_start(p, s);
        verror_msg(s, p);
        va_end(p);
        fprintf(stderr, "\n");
}

static attribute_noreturn void err(int errnum, const char *s, ...)
{
        va_list p;

        va_start(p, s);
        verror_msg(s, p);
        va_end(p);
        fprintf(stderr, "\n");
        exit(errnum);
}

static void vperror_msg(const char *s, va_list p)
{
        int e = errno;

        if (s == 0)
                s = "";
        verror_msg(s, p);
        if (*s)
                s = ": ";
        fprintf(stderr, "%s%s\n", s, strerror(e));
}

static void warn(const char *s, ...)
{
        va_list p;

        va_start(p, s);
        vperror_msg(s, p);
        va_end(p);
}
#else
# include <err.h>
#endif

static void *xmalloc(size_t size)
{
        void *ptr;
        if ((ptr = malloc(size)) == NULL)
                err(EXIT_FAILURE, "out of memory");
        return ptr;
}

static char *xstrdup(const char *str)
{
        char *ptr;
        if ((ptr = strdup(str)) == NULL)
                err(EXIT_FAILURE, "out of memory");
        return ptr;
}

#undef __ELF_NATIVE_CLASS
#undef readsonameXX
#define readsonameXX readsoname32
#define __ELF_NATIVE_CLASS 32
#include "readsoname2.c"

#undef __ELF_NATIVE_CLASS
#undef readsonameXX
#define readsonameXX readsoname64
#define __ELF_NATIVE_CLASS 64
#include "readsoname2.c"
static char *readsoname(char *name, FILE *infile, int expected_type,
                        int *type, int elfclass)
{
        char *res;

        if (elfclass == ELFCLASS32)
                res = readsoname32(name, infile, expected_type, type);
        else {
                res = readsoname64(name, infile, expected_type, type);

                // For 64-bit glibc compatibility
                *type |= FLAG_X8664_LIB64;
        }

        return res;
}

/* If shared library, return a malloced copy of the soname and set the
 * type, else return NULL.
 *
 * expected_type should be either LIB_ANY or one of the following:-
 * LIB_DLL
 * LIB_ELF
 * LIB_ELF_LIBC5
 * LIB_ELF_LIBC6
 *
 * If the lib is ELF and we can not deduce the type the type will
 * be set based on expected_type.
 *
 * If the expected, actual/deduced types missmatch we display a warning
 * and use the actual/deduced type.
 */
static char *is_shlib(const char *dir, const char *name, int *type,
                      int *islink, int expected_type)
{
        char *good = NULL;
        char *cp, *cp2;
        FILE *file;
        struct exec exec;
        ElfW(Ehdr) *elf_hdr;
        struct stat statbuf;
        char buff[BUFFER_SIZE];
        char real[BUFFER_SIZE];
        static int byteswapflag = -1;   /* start with byte-order unknown */

        /* see if name is of the form *.so* */
        if (name[strlen(name) - 1] != '~' && (cp = strstr(name, ".so"))) {
                /* find the start of the Vminor part, if any */
                if (cp[3] == '.' && (cp2 = strchr(cp + 4, '.')))
                        cp = cp2;
                else
                        cp = cp + strlen(cp);

                /* construct the full path name */
                sprintf(buff, "%s%s%s", dir, (*dir && strcmp(dir, "/")) ? "/" : "", name);

                /* get real path in case of chroot */
                if (!chroot_realpath(chroot_dir, buff, real))
                        warn("can't resolve %s in chroot %s", buff, chroot_dir);

                /* first, make sure it's a regular file */
                if (lstat(real, &statbuf))
                        warn("skipping %s", buff);
                else if (!S_ISREG(statbuf.st_mode) && !S_ISLNK(statbuf.st_mode))
                        warnx("%s is not a regular file or symlink, skipping", buff);
                else {
                        /* is it a regular file or a symlink */
                        *islink = S_ISLNK(statbuf.st_mode);

                        /* then try opening it */
                        if (!(file = fopen(real, "rb")))
                                warn("skipping %s", buff);
                        else {
                                /* now make sure it's a shared library */
                                if (fread(&exec, sizeof exec, 1, file) < 1)
                                        warnx("can't read header from %s, skipping", buff);
                                else if (N_MAGIC(exec) != ZMAGIC
                                 && N_MAGIC(exec) != QMAGIC
                                 && N_MAGIC_SWAP(exec) != ZMAGIC
                                 && N_MAGIC_SWAP(exec) != QMAGIC) {
                                        elf_hdr = (ElfW(Ehdr) *) & exec;
                                        if (elf_hdr->e_ident[0] != 0x7f ||
                                            strncmp((const char *)elf_hdr->e_ident + 1, "ELF", 3) != 0)
                                        {
                                                /* silently ignore linker scripts */
                                                if (strncmp((const char *)&exec, "/* GNU ld", 9) != 0)
                                                        warnx("%s is not a shared library, skipping", buff);
                                        } else {
                                                /* always call readsoname to update type */
                                                if (expected_type == LIB_DLL) {
                                                        warnx("%s is not an a.out library, it's ELF!", buff);
                                                        expected_type = LIB_ANY;
                                                }
                                                *type = LIB_ELF;
                                                good = readsoname(buff, file, expected_type, type,
                                                                  elf_hdr->e_ident[EI_CLASS]);
                                                if (byteswapflag == -1)
                                                        /* byte-order detected */
                                                        byteswapflag = byteswap;
                                                if (good == NULL || *islink) {
                                                        if (good != NULL)
                                                                free(good);
                                                        good = xstrdup(name);
                                                } else {
                                                        /* if the soname does not match the filename,
                                                           issue a warning, but only in debug mode. */
                                                        int len = strlen(good);
                                                        if (debug && (strncmp((const char *)good, name, len) != 0
                                                            || (name[len] != '\0' && name[len] != '.')))
                                                                warnx("%s has inconsistent soname (%s)", buff, good);
                                                }
                                        }
                                } else {
                                        /* Determine byte-order */
                                        byteswap = (N_MAGIC(exec) == ZMAGIC || N_MAGIC(exec) == QMAGIC) ? 0 : 1;
                                        if (byteswapflag == -1)
                                                /* byte-order detected */
                                                byteswapflag = byteswap;

                                        if (*islink)
                                                good = xstrdup(name);
                                        else {
                                                good = xmalloc(cp - name + 1);
                                                strncpy(good, name, cp - name);
                                                good[cp - name] = '\0';
                                        }
                                        if (expected_type != LIB_ANY && expected_type != LIB_DLL) {
                                                warnx("%s is not an ELF library, its an a.out DLL!", buff);
                                                expected_type = LIB_ANY;
                                        }

                                        *type = LIB_DLL;
                                }
                                fclose(file);

                                if (byteswapflag >= 0 && byteswap != byteswapflag) {
                                        byteswapflag = -2;
                                        warnx("mixed byte-order detected, using host byte-order...");
                                }
                                if (byteswapflag == -2)
                                        byteswap = 0;
                        }
                }
        }

        return good;
}

/* update the symlink to new library */
static void link_shlib(const char *dir, const char *file, const char *so)
{
        int change = 1;
        char libname[BUFFER_SIZE];
        char linkname[BUFFER_SIZE];
        char reallibname[BUFFER_SIZE];
        char reallinkname[BUFFER_SIZE];
        struct stat libstat;
        struct stat linkstat;

        /* construct the full path names */
        sprintf(libname, "%s/%s", dir, file);
        sprintf(linkname, "%s/%s", dir, so);
        if (!chroot_realpath(chroot_dir, libname, reallibname))
                warn("can't resolve %s in chroot %s", libname, chroot_dir);
        if (!chroot_realpath(chroot_dir, linkname, reallinkname))
                warn("can't resolve %s in chroot %s", linkname, chroot_dir);

        /* see if a link already exists */
        if (!stat(reallinkname, &linkstat)) {
                /* now see if it's the one we want */
                if (stat(reallibname, &libstat))
                        warn("can't stat %s", libname);
                else if (libstat.st_dev == linkstat.st_dev &&
                         libstat.st_ino == linkstat.st_ino)
                        change = 0;
        }

        /* then update the link, if required */
        if (change > 0 && !nolinks) {
                if (!lstat(reallinkname, &linkstat)) {
                        if (!S_ISLNK(linkstat.st_mode)) {
                                warnx("%s is not a symlink", linkname);
                                change = -1;
                        } else if (remove(reallinkname)) {
                                warn("can't unlink %s", linkname);
                                change = -1;
                        }
                }
                if (change > 0) {
                        if (symlink(file, reallinkname)) {
                                warn("can't link %s to %s", linkname, file);
                                change = -1;
                        }
                }
        }

        /* some people like to know what we're doing */
        if (verbose > 0)
                printf("\t%s => %s%s\n", so, file,
                       change < 0 ? " (SKIPPED)" :
                       (change > 0 ? " (changed)" : ""));

        return;
}

/* figure out which library is greater */
static int libcmp(char *p1, char *p2)
{
        while (*p1) {
                if (isdigit(*p1) && isdigit(*p2)) {
                        /* must compare this numerically */
                        int v1, v2;
                        v1 = strtoul(p1, &p1, 10);
                        v2 = strtoul(p2, &p2, 10);
                        if (v1 != v2)
                                return v1 - v2;
                } else if (isdigit(*p1) && !isdigit(*p2))
                        return 1;
                else if (!isdigit(*p1) && isdigit(*p2))
                        return -1;
                else if (*p1 != *p2)
                        return *p1 - *p2;
                else
                        p1++, p2++;
        }

        return *p1 - *p2;
}

struct lib {
        char *so;               /* soname of a library */
        char *name;             /* name of a library */
        int libtype;            /* type of a library */
        int islink;             /* is it a symlink */
        struct lib *next;       /* next library in list */
};

/* update all shared library links in a directory */
static void scan_dir(const char *rawname)
{
        DIR *dir;
        const char *name;
        struct dirent *ent;
        char *so, *path, *path_n;
        struct lib *lp, *libs = NULL;
        int i, libtype, islink, expected_type = LIB_ANY;
        char realname[BUFFER_SIZE];

        /* We need a writable copy of this string */
        path = strdup(rawname);
        if (!path) {
                err(EXIT_FAILURE, "Out of memory!\n");
        }
        /* Eliminate all double //s */
        path_n = path;
        while ((path_n = strstr(path_n, "//"))) {
                i = strlen(path_n);
                memmove(path_n, path_n + 1, i - 1);
                *(path_n + i - 1) = '\0';
        }
        name = path;

#if 0
        char *t;
        /* Check for an embedded expected type */
        t = strrchr(name, '=');
        if (t) {
                *t++ = '\0';    /* Skip = char */
                if (strcasecmp(t, "libc4") == 0) {
                        expected_type = LIB_DLL;
                } else {
                        if (strcasecmp(t, "libc5") == 0) {
                                expected_type = LIB_ELF_LIBC5;
                        } else {
                                if (strcasecmp(t, "libc6") == 0) {
                                        expected_type = LIB_ELF_LIBC6;
                                } else {
                                        if (strcasecmp(t, "libc0") == 0) {
                                                expected_type = LIB_ELF_LIBC0;
                                        } else {
                                                warnx("Unknown type field '%s' for dir '%s' - ignored", t, name);
                                                expected_type = LIB_ANY;
                                        }
                                }
                        }
                }
        }
#endif

        /* let 'em know what's going on */
        if (verbose > 0)
                printf("%s:\n", name);

        /* get real path in case of chroot */
        if (!chroot_realpath(chroot_dir, name, realname))
                warn("can't resolve %s in chroot %s", name, chroot_dir);

        /* if we can't open it, we can't do anything */
        if ((dir = opendir(realname)) == NULL) {
                warn("skipping %s", name);
                free(path);
                return;
        }

        /* yes, we have to look at every single file */
        while ((ent = readdir(dir)) != NULL) {
                /* if it's not a shared library, don't bother */
                if ((so = is_shlib(name, ent->d_name, &libtype, &islink, expected_type)) == NULL)
                        continue;

                /* have we already seen one with the same so name? */
                for (lp = libs; lp; lp = lp->next) {
                        if (strcmp(so, lp->so) == 0) {
                                /* we have, which one do we want to use? */
                                if ((!islink && lp->islink) ||
                                    (islink == lp->islink &&
                                     libcmp(ent->d_name, lp->name) > 0)) {
                                        /* let's use the new one */
                                        free(lp->name);
                                        lp->name = xstrdup(ent->d_name);
                                        lp->libtype = libtype;
                                        lp->islink = islink;
                                }
                                break;
                        }
                }

                /* congratulations, you're the first one we've seen */
                if (!lp) {
                        lp = xmalloc(sizeof *lp);
                        lp->so = xstrdup(so);
                        lp->name = xstrdup(ent->d_name);
                        lp->libtype = libtype;
                        lp->islink = islink;
                        lp->next = libs;
                        libs = lp;
                }

                free(so);
        }

        /* don't need this any more */
        closedir(dir);

        /* now we have all the latest libs, update the links */
        for (lp = libs; lp; lp = lp->next) {
                if (!lp->islink)
                        link_shlib(name, lp->name, lp->so);
                if (!nocache)
                        cache_dolib(name, lp->so, lp->libtype);
        }

        /* always try to clean up after ourselves */
        while (libs) {
                lp = libs->next;
                free(libs->so);
                free(libs->name);
                free(libs);
                libs = lp;
        }

        free(path);
        return;
}

#ifndef __LDSO_CACHE_SUPPORT__
void cache_print(void)
{
        printf("Library cache disabled\n");
}
void cache_dolib(const char *dir, const char *so, int libtype)
{
        return;
}
void cache_write(void)
{
        return;
}
#else
/* return the list of system-specific directories */
static char *get_extpath(void)
{
        char *res = NULL, *cp;
        FILE *file;
        struct stat st;
        char realconffile[BUFFER_SIZE];

        if (!chroot_realpath(chroot_dir, conffile, realconffile))
                return NULL;

        if ((file = fopen(realconffile, "r")) != NULL) {
                fstat(fileno(file), &st);
                res = xmalloc(st.st_size + 1);
                (void)fread(res, 1, st.st_size, file);
                fclose(file);
                res[st.st_size] = '\0';

                /* convert comments fo spaces */
                for (cp = res; *cp; /*nada */ ) {
                        if (*cp == '#') {
                                do
                                        *cp++ = ' ';
                                while (*cp && *cp != '\n');
                        } else {
                                cp++;
                        }
                }
        }

        return res;
}

typedef struct liblist {
        int flags;
        int sooffset;
        int liboffset;
        char *soname;
        char *libname;
        struct liblist *next;
} liblist_t;

static header_t magic = { LDSO_CACHE_MAGIC, LDSO_CACHE_VER, 0 };
static liblist_t *lib_head = NULL;

static int liblistcomp(liblist_t *x, liblist_t *y)
{
        int res;

        if ((res = libcmp(x->soname, y->soname)) == 0) {
                res = libcmp(strrchr(x->libname, '/') + 1,
                             strrchr(y->libname, '/') + 1);
        }

        return res;
}

void cache_dolib(const char *dir, const char *so, int libtype)
{
        char fullpath[PATH_MAX];
        liblist_t *new_lib, *cur_lib;

        magic.nlibs++;
        sprintf(fullpath, "%s/%s", dir, so);
        new_lib = xmalloc(sizeof(liblist_t));
        new_lib->flags = libtype;
        new_lib->soname = xstrdup(so);
        new_lib->libname = xstrdup(fullpath);

        if (lib_head == NULL || liblistcomp(new_lib, lib_head) > 0) {
                new_lib->next = lib_head;
                lib_head = new_lib;
        } else {
                for (cur_lib = lib_head; cur_lib->next != NULL &&
                     liblistcomp(new_lib, cur_lib->next) <= 0;
                     cur_lib = cur_lib->next)
                        /* nothing */ ;
                new_lib->next = cur_lib->next;
                cur_lib->next = new_lib;
        }
}

void cache_write(void)
{
        int cachefd;
        int stroffset = 0;
        char realcachefile[BUFFER_SIZE];
        char tempfile[BUFFER_SIZE];
        header_t swap_magic;
        header_t *magic_ptr;
        libentry_t swap_lib;
        libentry_t *lib_ptr;
        liblist_t *cur_lib;

        if (!magic.nlibs)
                return;

        if (!chroot_realpath(chroot_dir, cachefile, realcachefile))
                err(EXIT_FAILURE, "can't resolve %s in chroot %s (%s)",
                    cachefile, chroot_dir, strerror(errno));

        sprintf(tempfile, "%s~", realcachefile);

        if (unlink(tempfile) && errno != ENOENT)
                err(EXIT_FAILURE, "can't unlink %s~ (%s)", cachefile,
                    strerror(errno));

        if ((cachefd = creat(tempfile, 0644)) < 0)
                err(EXIT_FAILURE, "can't create %s~ (%s)", cachefile,
                    strerror(errno));

        if (byteswap) {
                swap_magic = magic;
                swap_magic.nlibs = bswap_32(swap_magic.nlibs);
                magic_ptr = &swap_magic;
        } else {
                magic_ptr = &magic;
        }
        if (write(cachefd, magic_ptr, sizeof(header_t)) != sizeof(header_t))
                err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
                    strerror(errno));

        for (cur_lib = lib_head; cur_lib != NULL; cur_lib = cur_lib->next) {
                cur_lib->sooffset = stroffset;
                stroffset += strlen(cur_lib->soname) + 1;
                cur_lib->liboffset = stroffset;
                stroffset += strlen(cur_lib->libname) + 1;
                if (byteswap) {
                        swap_lib.flags = bswap_32(cur_lib->flags);
                        swap_lib.sooffset = bswap_32(cur_lib->sooffset);
                        swap_lib.liboffset = bswap_32(cur_lib->liboffset);
                        lib_ptr = &swap_lib;
                } else {
                        lib_ptr = (libentry_t *) cur_lib;
                }
                if (write(cachefd, lib_ptr, sizeof(libentry_t)) !=
                    sizeof(libentry_t))
                        err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
                            strerror(errno));
        }

        for (cur_lib = lib_head; cur_lib != NULL; cur_lib = cur_lib->next) {
                if ((size_t)write(cachefd, cur_lib->soname, strlen(cur_lib->soname) + 1)
                    != strlen(cur_lib->soname) + 1)
                        err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
                            strerror(errno));
                if ((size_t)write(cachefd, cur_lib->libname, strlen(cur_lib->libname) + 1)
                    != strlen(cur_lib->libname) + 1)
                        err(EXIT_FAILURE, "can't write %s~ (%s)", cachefile,
                            strerror(errno));
        }

        if (close(cachefd))
                err(EXIT_FAILURE, "can't close %s~ (%s)", cachefile,
                    strerror(errno));

        if (chmod(tempfile, 0644))
                err(EXIT_FAILURE, "can't chmod %s~ (%s)", cachefile,
                    strerror(errno));

        if (rename(tempfile, realcachefile))
                err(EXIT_FAILURE, "can't rename %s~ (%s)", cachefile,
                    strerror(errno));
}

void cache_print(void)
{
        caddr_t c;
        struct stat st;
        int fd = 0;
        char *strs;
        header_t *header;
        libentry_t *libent;
        char realcachefile[BUFFER_SIZE];

        if (!chroot_realpath(chroot_dir, cachefile, realcachefile))
                err(EXIT_FAILURE, "can't resolve %s in chroot %s (%s)",
                    cachefile, chroot_dir, strerror(errno));

        if (stat(realcachefile, &st) || (fd = open(realcachefile, O_RDONLY)) < 0)
                err(EXIT_FAILURE, "can't read %s (%s)", cachefile, strerror(errno));

        c = mmap(0, st.st_size, PROT_READ, LDSO_CACHE_MMAP_FLAGS, fd, 0);
        if (c == MAP_FAILED)
                err(EXIT_FAILURE, "can't map %s (%s)", cachefile, strerror(errno));
        close(fd);

        if (memcmp(((header_t *) c)->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN))
                err(EXIT_FAILURE, "%s cache corrupt", cachefile);

        if (memcmp(((header_t *) c)->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN))
                err(EXIT_FAILURE, "wrong cache version - expected %s",
                    LDSO_CACHE_VER);

        header = (header_t *) c;
        libent = (libentry_t *) (c + sizeof(header_t));
        strs = (char *)&libent[header->nlibs];

        printf("%d libs found in cache `%s' (version %s)\n",
               header->nlibs, cachefile, LDSO_CACHE_VER);

        for (fd = 0; fd < header->nlibs; fd++) {
                printf("\t%s ", strs + libent[fd].sooffset);
                switch (libent[fd].flags & ~LIB_ELF64 & FLAG_TYPE_MASK) {
                case LIB_DLL:
                        printf("(libc4)");
                        break;
                case LIB_ELF:
                        printf("(ELF%s)", libent[fd].flags & LIB_ELF64 ? "/64" : "");
                        break;
                case LIB_ELF_LIBC0:
                        printf("(libc0%s)", libent[fd].flags & LIB_ELF64 ? "/64" : "");
                        break;
                case LIB_ELF_LIBC5:
                case LIB_ELF_LIBC6:
                        printf("(libc%d%s)",
                               (libent[fd].flags & ~LIB_ELF64 & FLAG_TYPE_MASK) + 3,
                               libent[fd].flags & LIB_ELF64 ? "/64" : "");
                        break;
                default:
                        printf("(unknown)");
                        break;
                }
                printf(" => %s\n", strs + libent[fd].liboffset);
        }

        munmap(c, st.st_size);
}
#endif

static attribute_noreturn void usage(void)
{
        fprintf(stderr,
#ifdef __LDSO_CACHE_SUPPORT__
                "ldconfig - updates symlinks and cache for shared libraries\n\n"
                "Usage: ldconfig [-DvqnNX] [-f conf] [-C cache] [-r root] dir ...\n"
                "       ldconfig -l [-Dv] lib ...\n"
                "       ldconfig -p\n\nOptions:\n"
#else
                "ldconfig - updates symlinks for shared libraries\n\n"
                "Usage: ldconfig [-DvqnX] [-r root] dir ...\n"
                "       ldconfig -l [-Dv] lib ...\n\nOptions:\n"
#endif
                "\t-D:\t\tdebug mode, don't update links\n"
                "\t-v:\t\tverbose mode, print things as we go\n"
                "\t-q:\t\tquiet mode, don't print warnings\n"
                "\t-n:\t\tdon't process standard directories\n"
                "\t-N:\t\tdon't update the library cache\n"
                "\t-X:\t\tdon't update the library links\n"
                "\t-l:\t\tlibrary mode, manually link libraries\n"
                "\t-p:\t\tprint the current library cache\n"
#ifdef __LDSO_CACHE_SUPPORT__
                "\t-f conf :\tuse conf instead of %s\n"
                "\t-C cache:\tuse cache instead of %s\n"
#endif
                "\t-r root :\tfirst, do a chroot to the indicated directory\n"
                "\tdir ... :\tdirectories to process\n"
#ifdef __LDSO_CACHE_SUPPORT__
                "\tlib ... :\tlibraries to link\n\n", LDSO_CONF, LDSO_CACHE
#else
                "\tlib ... :\tlibraries to link\n\n"
#endif
            );
        exit(EXIT_FAILURE);
}

#define DIR_SEP      ":, \t\n"
int main(int argc, char **argv)
{
        int i, c;
        int nodefault = 0;
        char *cp, *dir, *so;
        int libtype, islink;
        int printcache = 0;
#ifdef __LDSO_CACHE_SUPPORT__
        char *extpath;
#endif

        prog = argv[0];
        opterr = 0;

        while ((c = getopt(argc, argv, "DvqnNXlpf:C:r:")) != EOF)
                switch (c) {
                case 'D':
                        debug = 1;      /* debug mode */
                        nocache = 1;
                        nolinks = 1;
                        verbose = 1;
                        break;
                case 'v':
                        verbose = 1;    /* verbose mode */
                        break;
                case 'q':
                        if (verbose <= 0)
                                verbose = -1;   /* quiet mode */
                        break;
                case 'n':
                        nodefault = 1;  /* no default dirs */
                        nocache = 1;
                        break;
                case 'N':
                        nocache = 1;    /* don't build cache */
                        break;
                case 'X':
                        nolinks = 1;    /* don't update links */
                        break;
                case 'l':
                        libmode = 1;    /* library mode */
                        break;
                case 'p':
                        printcache = 1; /* print cache */
                        break;
                case 'f':
#ifdef __LDSO_CACHE_SUPPORT__
                        conffile = optarg;      /* alternate conf file */
#endif
                        break;
                case 'C':
#ifdef __LDSO_CACHE_SUPPORT__
                        cachefile = optarg;     /* alternate cache file */
#endif
                        break;
                case 'r':
                        chroot_dir = optarg;
                        break;
                default:
                        usage();
                        break;

                        /* THE REST OF THESE ARE UNDOCUMENTED AND MAY BE REMOVED
                           IN FUTURE VERSIONS. */
                }

        if (chroot_dir && *chroot_dir) {
                if (chroot(chroot_dir) < 0) {
                        if (chdir(chroot_dir) < 0)
                                err(EXIT_FAILURE, "couldn't chroot to %s (%s)", chroot_dir, strerror(errno));
                        chroot_dir = ".";
                } else {
                        if (chdir("/") < 0)
                                err(EXIT_FAILURE, "couldn't chdir to / (%s)", strerror(errno));
                        chroot_dir = NULL;
                }
        }

        /* allow me to introduce myself, hi, my name is ... */
        if (verbose > 0)
                printf("%s: uClibc version\n", argv[0]);

        if (printcache) {
                /* print the cache -- don't you trust me? */
                cache_print();
                exit(EXIT_SUCCESS);
        } else if (libmode) {
                /* so you want to do things manually, eh? */

                /* ok, if you're so smart, which libraries do we link? */
                for (i = optind; i < argc; i++) {
                        /* split into directory and file parts */
                        if (!(cp = strrchr(argv[i], '/'))) {
                                dir = ".";      /* no dir, only a filename */
                                cp = argv[i];
                        } else {
                                if (cp == argv[i])
                                        dir = "/";      /* file in root directory */
                                else
                                        dir = argv[i];
                                *cp++ = '\0';   /* neither of the above */
                        }

                        /* we'd better do a little bit of checking */
                        if ((so = is_shlib(dir, cp, &libtype, &islink, LIB_ANY)) == NULL)
                                err(EXIT_FAILURE, "%s%s%s is not a shared library",
                                    dir, (*dir && strcmp(dir, "/")) ? "/" : "", cp);

                        /* so far, so good, maybe he knows what he's doing */
                        link_shlib(dir, cp, so);
                }
        } else {
                /* the lazy bum want's us to do all the work for him */

                /* don't cache dirs on the command line */
                int nocache_save = nocache;
                nocache = 1;

                /* OK, which directories should we do? */
                for (i = optind; i < argc; i++)
                        scan_dir(argv[i]);

                /* restore the desired caching state */
                nocache = nocache_save;

                /* look ma, no defaults */
                if (!nodefault) {
                        scan_dir(UCLIBC_RUNTIME_PREFIX "lib");
                        scan_dir(UCLIBC_RUNTIME_PREFIX "usr/lib");
#ifndef __LDSO_CACHE_SUPPORT__
                        scan_dir(UCLIBC_RUNTIME_PREFIX "usr/X11R6/lib");
#else
                        /* I guess the defaults aren't good enough */
                        if ((extpath = get_extpath())) {
                                for (cp = strtok(extpath, DIR_SEP); cp; cp = strtok(NULL, DIR_SEP)) {
                                        /* strip trailing slashes */
                                        int len = strlen(cp);
                                        if (len)
                                                while (cp[--len] == '/' && len)
                                                        cp[len] = 0;
                                        /* we do the redundancy check only if cache usage is enabled */
                                        if (strcmp(UCLIBC_RUNTIME_PREFIX "lib", cp) == 0
                                            || strcmp(UCLIBC_RUNTIME_PREFIX "usr/lib", cp) == 0) {
                                                if (verbose >= 0)
                                                        warnx("You should remove `%s' from `%s'", cp, LDSO_CONF);
                                                continue;
                                        }
                                        scan_dir(cp);
                                }
                                free(extpath);
                        }
#endif
                }

                if (!nocache)
                        cache_write();
        }

        exit(EXIT_SUCCESS);
}