Merge commit 'a058d1cc571af5fbcfe7f1d719df1abbfdb722f3' into merges

[unleashed.git] / usr / src / cmd / expr / compile.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 1995-2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

/*
 * xcompile, xstep, xadvance - simulate compile(3g), step(3g), advance(3g)
 *      using regcomp(3c), regexec(3c) interfaces. This is an XCU4
 *      porting aid. switches out to libgen compile/step if collation
 *      table not present.
 *
 *      Goal is to work with vi and sed/ed.
 *      Returns expbuf in dhl format (encoding of first two bytes).
 *      Note also that this is profoundly single threaded.  You
 *      cannot call compile twice with two separate search strings
 *      because the second call will wipe out the earlier stored string.
 *      This must be fixed, plus a general cleanup should be performed
 *      if this is to be integrated into libc.
 *
 */

#include <stdio.h>
#include <widec.h>
#include <sys/types.h>
#include <regex.h>
#include <locale.h>
#include <stdlib.h>
#include <locale.h>
#include <string.h>
#include <unistd.h>
#include <regexpr.h>

int regcomp_flags;              /* interface to specify cflags for regcomp */

void regex_comp_free(void *a);
static int dhl_step(const char *str, const char *ep);
static int dhl_advance(const char *str, const char *ep);
static int map_errnos(int);             /* Convert regcomp error */
static int dhl_doit(const char *, const regex_t *, const int flags);
static char *dhl_compile(const char *instr, char *ep, char *endbuf);

/*
 * # of sub re's: NOTE: For now limit on bra list defined here
 * but fix is to add maxbra define to to regex.h
 * One problem is that a bigger number is a performance hit since
 * regexec() has a slow initialization loop that goes around SEPSIZE times
 */
#define SEPSIZE 20
static regmatch_t rm[SEPSIZE];          /* ptr to list of RE matches */

/*
 * Structure to contain dl encoded first two bytes for vi, plus hold two
 * regex structures, one for advance and one for step.
 */
static struct regex_comp {
        char    r_head[2];              /* Header for DL encoding for vi */
        regex_t r_stp;                  /* For use by step */
        regex_t r_adv;                  /* For use by advance */
} reg_comp;

/*
 * global value for the size of a regex_comp structure:
 */
size_t regexc_size = sizeof (reg_comp);


char *
compile(const char *instr, char *expbuf, char *endbuf)
{
        return (dhl_compile(instr, expbuf, endbuf));
}

int
step(const char *instr, const char *expbuf)
{
        return (dhl_step(instr, expbuf));
}

int
advance(const char *instr, const char *expbuf)
{
        return (dhl_advance(instr, expbuf));
}


/*
 * the compile and step routines here simulate the old libgen routines of
 * compile/step Re: regexpr(3G). in order to do this, we must assume
 * that expbuf[] consists of the following format:
 *      1) the first two bytes consist of a special encoding - see below.
 *      2) the next part is a regex_t used by regexec()/regcomp() for step
 *      3) the final part is a regex_t used by regexec()/regcomp() for advance
 *
 * the special encoding of the first two bytes is referenced throughout
 * vi. apparently expbuf[0] is set to:
 *      = 0 upon initialization
 *      = 1 if the first char of the RE is a ^
 *      = 0 if the first char of the RE isn't a ^
 * and expbuf[1-35+]    = bitmap of the type of RE chars in the expression.
 * this is apparently 0 if there's no RE.
 * Here, we use expbuf[0] in a similar fashion; and expbuf[1] is non-zero
 * if there's at least 1 RE in the string.
 * I say "apparently" as the code to compile()/step() is poorly written.
 */
static char *
dhl_compile(instr, expbuf, endbuf)
const char *instr;              /* the regular expression               */
char *expbuf;                   /* where the compiled RE gets placed    */
char *endbuf;                   /* ending addr of expbuf                */
{
        int rv;
        int alloc = 0;
        char adv_instr[4096];   /* PLENTY big temp buffer */
        char *instrp;           /* PLENTY big temp buffer */

        if (*instr == '\0') {
                regerrno = 41;
                return (NULL);
        }

        /*
         * Check values of expbuf and endbuf
         */
        if (expbuf == NULL) {
                if ((expbuf = malloc(regexc_size)) == NULL) {
                        regerrno = 50;
                        return (NULL);
                }
                memset(&reg_comp, 0, regexc_size);
                alloc = 1;
                endbuf = expbuf + regexc_size;
        } else {                /* Check if enough memory was allocated */
                if (expbuf + regexc_size > endbuf) {
                        regerrno = 50;
                        return (NULL);
                }
                memcpy(&reg_comp, expbuf, regexc_size);
        }

        /*
         * Clear global flags
         */
        nbra = 0;
        regerrno = 0;

        /*
         * Free any data being held for previous search strings
         */
        regex_comp_free(&reg_comp);

        /*
         * We call regcomp twice, once to get a regex_t for use by step()
         * and then again with for use by advance()
         */
        if ((rv = regcomp(&reg_comp.r_stp, instr, regcomp_flags)) != 0) {
                regerrno = map_errnos(rv);      /* Convert regcomp error */
                goto out;
        }
        /*
         * To support advance, which assumes an implicit ^ to match at start
         * of line we prepend a ^ to the pattern by copying to a temp buffer
         */

        if (instr[0] == '^')
                instrp = (char *)instr; /* String already has leading ^ */
        else {
                adv_instr[0] = '^';
                strncpy(&adv_instr[1], instr, 2048);
                instrp = adv_instr;
        }

        if ((rv = regcomp(&reg_comp.r_adv, instrp, regcomp_flags)) != 0) {
                regerrno = map_errnos(rv);      /* Convert regcomp error */
                goto out;
        }

        /*
         * update global variables
         */
        nbra = (int)reg_comp.r_adv.re_nsub > 0 ?
            (int)reg_comp.r_adv.re_nsub : 0;
        regerrno = 0;

        /*
         * Set the header flags for use by vi
         */
        if (instr[0] == '^')            /* if beginning of string,      */
                reg_comp.r_head[0] = 1; /* set special flag             */
        else
                reg_comp.r_head[0] = 0; /* clear special flag           */
        /*
         * note that for a single BRE, nbra will be 0 here.
         * we're guaranteed that, at this point, a RE has been found.
         */
        reg_comp.r_head[1] = 1; /* set special flag             */
        /*
         * Copy our reg_comp structure to expbuf
         */
        (void) memcpy(expbuf, (char *)&reg_comp, regexc_size);

out:
        /*
         * Return code from libgen regcomp with mods.  Note weird return
         * value - if space is malloc'd return pointer to start of space,
         * if user provided their own space, return pointer to 1+last byte
         * of that space.
         */
        if (regerrno != 0) {
                if (alloc)
                        free(expbuf);
                return (NULL);
        }
        reglength = regexc_size;

        if (alloc)
                return (expbuf);
        else
                return (expbuf + regexc_size);
}


/*
 * dhl_step: step through a string until a RE match is found, or end of str
 */
static int
dhl_step(str, ep)
const char *str;                /* characters to be checked for a match */
const char *ep;                 /* compiled RE from dhl_compile()       */
{
        /*
         * Check if we're passed a null ep
         */
        if (ep == NULL) {
                regerrno = 41;  /* No remembered search string error */
                return (0);
        }
        /*
         * Call common routine with r_stp (step) structure
         */
        return (dhl_doit(str, &(((struct regex_comp *)ep)->r_stp),
            ((locs != NULL) ? REG_NOTBOL : 0)));
}

/*
 * dhl_advance: implement advance
 */
static int
dhl_advance(str, ep)
const char *str;                /* characters to be checked for a match */
const char *ep;                 /* compiled RE from dhl_compile()       */
{
        int rv;
        /*
         * Check if we're passed a null ep
         */
        if (ep == NULL) {
                regerrno = 41;  /* No remembered search string error */
                return (0);
        }
        /*
         * Call common routine with r_adv (advance) structure
         */
        rv = dhl_doit(str, &(((struct regex_comp *)ep)->r_adv), 0);
        loc1 = NULL;            /* Clear it per the compile man page */
        return (rv);
}

/*
 * dhl_doit - common code for step and advance
 */
static int
dhl_doit(str, rep, flags)
const char *str;                /* characters to be checked for a match */
const regex_t *rep;
const int flags;                /* flags to be passed to regexec directly */
{
        int rv;
        int i;
        regmatch_t *prm;        /* ptr to current regmatch_t            */

        /*
         * Check if we're passed a null regex_t
         */
        if (rep == NULL) {
                regerrno = 41;  /* No remembered search string error */
                return (0);
        }

        regerrno = 0;
        prm = &rm[0];

        if ((rv = regexec(rep, str, SEPSIZE, prm, flags)) != REG_OK) {
                if (rv == REG_NOMATCH)
                        return (0);
                regerrno = map_errnos(rv);
                return (0);
        }

        loc1 = (char *)str + prm->rm_so;
        loc2 = (char *)str + prm->rm_eo;

        /*
         * Now we need to fill up the bra lists with all of the sub re's
         * Note we subtract nsub -1, and preincrement prm.
         */
        for (i = 0; i <= rep->re_nsub; i++) {
                prm++;          /* XXX inc past first subexp */
                braslist[i] = (char *)str + prm->rm_so;
                braelist[i] = (char *)str + prm->rm_eo;
                if (i >= SEPSIZE) {
                        regerrno = 50;  /* regex overflow */
                        return (0);
                }
        }

        /*
         * Inverse logic, a zero from regexec - success, is a 1
         * from advance/step.
         */

        return (rv == 0);
}


/*
 *      regerrno to compile/step error mapping:
 *      This is really a big compromise.  Some errors don't map at all
 *      like regcomp error 15 is generated by both compile() error types
 *      44 & 46.  So which one should we map to?
 *      Note REG_ESUB Can't happen- 9 is no longer max num of subexpressions
 *      To do your errors right use xregerr() to get the regcomp error
 *      string and print that.
 *
 * |    regcomp/regexec              |  Compile/step/advance                |
 * +---------------------------------+--------------------------------------+
 * 0 REG_OK       Pattern matched       1  - Pattern matched
 * 1 REG_NOMATCH  No match              0  - Pattern didn't match
 * 2 REG_ECOLLATE Bad collation elmnt.  67 - Returned by compile on mbtowc err
 * 3 REG_EESCAPE  trailing \ in patrn   45 - } expected after \.
 * 4 REG_ENEWLINE \n before end pattrn  36 - Illegal or missing delimiter.
 * 5 REG_ENSUB    Over 9 \( \) pairs    43 - Too many \(
 * 6 REG_ESUBREG  Bad number in \[0-9]  25 - ``\digit'' out of range.
 * 7 REG_EBRACK   [ ] inbalance         49 - [ ] imbalance.
 * 8 REG_EPAREN   ( ) inbalance         42 - \(~\) imbalance.
 * 9 REG_EBRACE   \{ \} inbalance       45 - } expected after \.
 * 10 REG_ERANGE  bad range endpoint    11 - Range endpoint too large.
 * 11 REG_ESPACE  no memory for pattern 50 - Regular expression overflow.
 * 12 REG_BADRPT  invalid repetition    36 - Illegal or missing delimiter.
 * 13 REG_ECTYPE  invalid char-class    67 - illegal byte sequence
 * 14 REG_BADPAT  syntax error          50 - Regular expression overflow.
 * 15 REG_BADBR   \{ \} contents bad    46 - First number exceeds 2nd in \{~\}
 * 16 REG_EFATAL  internal error        50 - Regular expression overflow.
 * 17 REG_ECHAR   bad mulitbyte char    67 - illegal byte sequence
 * 18 REG_STACK   stack overflow        50 - Regular expression overflow.
 * 19 REG_ENOSYS  function not supported 50- Regular expression overflow.
 *
 *      For reference here's the compile/step errno's. We don't generate
 *      41 here - it's done earlier, nor 44 since we can't tell if from 46.
 *
 *      11 - Range endpoint too large.
 *      16 - Bad number.
 *      25 - ``\digit'' out of range.
 *      36 - Illegal or missing delimiter.
 *      41 - No remembered search string.
 *      42 - \(~\) imbalance.
 *      43 - Too many \(.
 *      44 - More than 2 numbers given in "\{~\}"
 *      45 - } expected after \.
 *      46 - First number exceeds 2nd in "\{~\}"
 *      49 - [ ] imbalance.
 *      50 - Regular expression overflow.
 */

static int
map_errnos(int Errno)
{
        switch (Errno) {
        case REG_ECOLLATE:
                regerrno = 67;
                break;
        case REG_EESCAPE:
                regerrno = 45;
                break;
        case REG_ENEWLINE:
                regerrno = 36;
                break;
        case REG_ENSUB:
                regerrno = 43;
                break;
        case REG_ESUBREG:
                regerrno = 25;
                break;
        case REG_EBRACK:
                regerrno = 49;
                break;
        case REG_EPAREN:
                regerrno = 42;
                break;
        case REG_EBRACE:
                regerrno = 45;
                break;
        case REG_ERANGE:
                regerrno = 11;
                break;
        case REG_ESPACE:
                regerrno = 50;
                break;
        case REG_BADRPT:
                regerrno = 36;
                break;
        case REG_ECTYPE:
                regerrno = 67;
                break;
        case REG_BADPAT:
                regerrno = 50;
                break;
        case REG_BADBR:
                regerrno = 46;
                break;
        case REG_EFATAL:
                regerrno = 50;
                break;
        case REG_ECHAR:
                regerrno = 67;
                break;
        case REG_STACK:
                regerrno = 50;
                break;
        case REG_ENOSYS:
                regerrno = 50;
                break;
        default:
                regerrno = 50;
                break;
        }
        return (regerrno);
}

/*
 *  This is a routine to clean up the subtle substructure of the struct
 *  regex_comp type for use by clients of this module.  Since the struct
 *  type is private, we use a generic interface, and trust the
 *  application to be damn sure that this operation is valid for the
 *  named memory.
 */

void
regex_comp_free(void * a)
{
        /*
         * Free any data being held for previous search strings
         */

        if (((struct regex_comp *)a) == NULL) {
                return;
        }

        regfree(&((struct regex_comp *)a)->r_stp);
        regfree(&((struct regex_comp *)a)->r_adv);
}