cmd/sed/process.c

/*
 * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1992 Diomidis Spinellis.
 * Copyright (c) 1992, 1993, 1994
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Diomidis Spinellis of Imperial College, University of London.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>
#include <wctype.h>
#include <termio.h>
#include <libintl.h>
#include <note.h>

#include "defs.h"
#include "extern.h"

static SPACE HS, PS, SS, YS;
#define pd      PS.deleted
#define ps      PS.space
#define psl     PS.len
#define hs      HS.space
#define hsl     HS.len

static int  applies(struct s_command *);
static void do_tr(struct s_tr *);
static void flush_appends(void);
static void lputs(char *, size_t);
static int   regexec_e(regex_t *, const char *, int, int, size_t);
static void regsub(SPACE *, char *, char *);
static int  substitute(struct s_command *);

struct s_appends *appends;  /* Array of pointers to strings to append. */
static int appendx;     /* Index into appends array. */
int appendnum;          /* Size of appends array. */

static int lastaddr;        /* Set by applies if last address of a range. */
static int sdone;       /* If any substitutes since last line input. */
                /* Iov structure for 'w' commands. */
static regex_t *defpreg;
size_t maxnsub;
regmatch_t *match;

#define OUT() do {                  \
    (void) fwrite(ps, 1, psl, outfile);     \
    (void) fputc('\n', outfile);            \
    _NOTE(CONSTCOND)                \
} while (0)

void
process(void)
{
    struct s_command *cp;
    SPACE tspace;
    size_t oldpsl = 0;
    char *p;

    p = NULL;

    for (linenum = 0; mf_fgets(&PS, REPLACE); /* NOP */) {
        pd = 0;
top:
        cp = prog;
redirect:
        while (cp != NULL) {
            if (!applies(cp)) {
                cp = cp->next;
                continue;
            }
            switch (cp->code) {
            case '{':
                cp = cp->u.c;
                goto redirect;
            case 'a':
                if (appendx >= appendnum)
                    if ((appends = realloc(appends,
                        sizeof (struct s_appends) *
                        (appendnum *= 2))) == NULL)
                        err(1, "realloc");
                appends[appendx].type = AP_STRING;
                appends[appendx].s = cp->t;
                appends[appendx].len = strlen(cp->t);
                appendx++;
                break;
            case 'b':
                cp = cp->u.c;
                goto redirect;
            case 'c':
                pd = 1;
                psl = 0;
                if (cp->a2 == NULL || lastaddr || lastline())
                    (void) fprintf(outfile, "%s", cp->t);
                break;
            case 'd':
                pd = 1;
                goto new;
            case 'D':
                if (pd)
                    goto new;
                if (psl == 0 ||
                    (p = memchr(ps, '\n', psl)) == NULL) {
                    pd = 1;
                    goto new;
                } else {
                    psl -=
                        (uintptr_t)(p + 1) - (uintptr_t)ps;
                    (void) memmove(ps, p + 1, psl);
                    goto top;
                }
            case 'g':
                cspace(&PS, hs, hsl, REPLACE);
                break;
            case 'G':
                cspace(&PS, "\n", 1, APPEND);
                cspace(&PS, hs, hsl, APPEND);
                break;
            case 'h':
                cspace(&HS, ps, psl, REPLACE);
                break;
            case 'H':
                cspace(&HS, "\n", 1, APPEND);
                cspace(&HS, ps, psl, APPEND);
                break;
            case 'i':
                (void) fprintf(outfile, "%s", cp->t);
                break;
            case 'l':
                lputs(ps, psl);
                break;
            case 'n':
                if (!nflag && !pd)
                    OUT();
                flush_appends();
                if (!mf_fgets(&PS, REPLACE))
                    exit(0);
                pd = 0;
                break;
            case 'N':
                flush_appends();
                cspace(&PS, "\n", 1, APPEND);
                if (!mf_fgets(&PS, APPEND))
                    exit(0);
                break;
            case 'p':
                if (pd)
                    break;
                OUT();
                break;
            case 'P':
                if (pd)
                    break;
                if ((p = memchr(ps, '\n', psl)) != NULL) {
                    oldpsl = psl;
                    psl = (uintptr_t)p - (uintptr_t)ps;
                }
                OUT();
                if (p != NULL)
                    psl = oldpsl;
                break;
            case 'q':
                if (!nflag && !pd)
                    OUT();
                flush_appends();
                exit(0);
                /*NOTREACHED*/
            case 'r':
                if (appendx >= appendnum)
                    if ((appends = realloc(appends,
                        sizeof (struct s_appends) *
                        (appendnum *= 2))) == NULL)
                        err(1, "realloc");
                appends[appendx].type = AP_FILE;
                appends[appendx].s = cp->t;
                appends[appendx].len = strlen(cp->t);
                appendx++;
                break;
            case 's':
                sdone |= substitute(cp);
                break;
            case 't':
                if (sdone) {
                    sdone = 0;
                    cp = cp->u.c;
                    goto redirect;
                }
                break;
            case 'w':
                if (pd)
                    break;
                if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
                    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 0666))
                    == -1)
                    err(1, "%s", cp->t);
                if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
                    write(cp->u.fd, "\n", 1) != 1)
                    err(1, "%s", cp->t);
                break;
            case 'x':
                /*
                 * If the hold space is null, make it empty
                 * but not null.  Otherwise the pattern space
                 * will become null after the swap, which is
                 * an abnormal condition.
                 */
                if (hs == NULL)
                    cspace(&HS, "", 0, REPLACE);
                tspace = PS;
                PS = HS;
                HS = tspace;
                break;
            case 'y':
                if (pd || psl == 0)
                    break;
                do_tr(cp->u.y);
                break;
            case ':':
            case '}':
                break;
            case '=':
                (void) fprintf(outfile, "%lu\n", linenum);
            }
            cp = cp->next;
        } /* for all cp */

new:        if (!nflag && !pd)
            OUT();
        flush_appends();
    } /* for all lines */
}

/*
 * TRUE if the address passed matches the current program state
 * (lastline, linenumber, ps).
 */
#define MATCH(a)                            \
    ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :  \
        (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())

/*
 * Return TRUE if the command applies to the current line.  Sets the start
 * line for process ranges.  Interprets the non-select (``!'') flag.
 */
static int
applies(struct s_command *cp)
{
    int r;

    lastaddr = 0;
    if (cp->a1 == NULL && cp->a2 == NULL)
        r = 1;
    else if (cp->a2)
        if (cp->startline > 0) {
            if (MATCH(cp->a2)) {
                cp->startline = 0;
                lastaddr = 1;
                r = 1;
            } else if (linenum - cp->startline <= cp->a2->u.l)
                r = 1;
            else if ((cp->a2->type == AT_LINE &&
                linenum > cp->a2->u.l) ||
                (cp->a2->type == AT_RELLINE &&
                linenum - cp->startline > cp->a2->u.l)) {
                /*
                 * We missed the 2nd address due to a branch,
                 * so just close the range and return false.
                 */
                cp->startline = 0;
                r = 0;
            } else
                r = 1;
        } else if (MATCH(cp->a1)) {
            /*
             * If the second address is a number less than or
             * equal to the line number first selected, only
             * one line shall be selected.
             *  -- POSIX 1003.2
             * Likewise if the relative second line address is zero.
             */
            if ((cp->a2->type == AT_LINE &&
                linenum >= cp->a2->u.l) ||
                (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
                lastaddr = 1;
            else {
                cp->startline = linenum;
            }
            r = 1;
        } else
            r = 0;
    else
        r = MATCH(cp->a1);
    return (cp->nonsel ? ! r : r);
}

/*
 * Reset the sed processor to its initial state.
 */
void
resetstate(void)
{
    struct s_command *cp;

    /*
     * Reset all in-range markers.
     */
    for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
        if (cp->a2)
            cp->startline = 0;

    /*
     * Clear out the hold space.
     */
    cspace(&HS, "", 0, REPLACE);
}

/*
 * substitute --
 *  Do substitutions in the pattern space.  Currently, we build a
 *  copy of the new pattern space in the substitute space structure
 *  and then swap them.
 */
static int
substitute(struct s_command *cp)
{
    SPACE tspace;
    regex_t *re;
    regoff_t re_off, slen;
    int lastempty, n;
    char *s;

    s = ps;
    re = cp->u.s->re;
    if (re == NULL) {
        if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
            linenum = cp->u.s->linenum;
            fatal(_("\\%u not defined in the RE"),
                cp->u.s->maxbref);
        }
    }
    if (!regexec_e(re, s, 0, 0, psl))
        return (0);

    SS.len = 0;             /* Clean substitute space. */
    slen = psl;
    n = cp->u.s->n;
    lastempty = 1;

    switch (n) {
    case 0:                 /* Global */
        do {
            if (lastempty || match[0].rm_so != match[0].rm_eo) {
                /* Locate start of replaced string. */
                re_off = match[0].rm_so;
                /* Copy leading retained string. */
                cspace(&SS, s, re_off, APPEND);
                /* Add in regular expression. */
                regsub(&SS, s, cp->u.s->new);
            }

            /* Move past this match. */
            if (match[0].rm_so != match[0].rm_eo) {
                s += match[0].rm_eo;
                slen -= match[0].rm_eo;
                lastempty = 0;
            } else {
                if (match[0].rm_so < slen)
                    cspace(&SS, s + match[0].rm_so, 1,
                        APPEND);
                s += match[0].rm_so + 1;
                slen -= match[0].rm_so + 1;
                lastempty = 1;
            }
        } while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, slen));
        /* Copy trailing retained string. */
        if (slen > 0)
            cspace(&SS, s, slen, APPEND);
        break;
    default:                /* Nth occurrence */
        while (--n) {
            if (match[0].rm_eo == match[0].rm_so)
                match[0].rm_eo = match[0].rm_so + 1;
            s += match[0].rm_eo;
            slen -= match[0].rm_eo;
            if (slen < 0)
                return (0);
            if (!regexec_e(re, s, REG_NOTBOL, 0, slen))
                return (0);
        }
        /* FALLTHROUGH */
    case 1:                 /* 1st occurrence */
        /* Locate start of replaced string. */
        re_off = match[0].rm_so + ((uintptr_t)s - (uintptr_t)ps);
        /* Copy leading retained string. */
        cspace(&SS, ps, re_off, APPEND);
        /* Add in regular expression. */
        regsub(&SS, s, cp->u.s->new);
        /* Copy trailing retained string. */
        s += match[0].rm_eo;
        slen -= match[0].rm_eo;
        cspace(&SS, s, slen, APPEND);
        break;
    }

    /*
     * Swap the substitute space and the pattern space, and make sure
     * that any leftover pointers into stdio memory get lost.
     */
    tspace = PS;
    PS = SS;
    SS = tspace;
    SS.space = SS.back;

    /* Handle the 'p' flag. */
    if (cp->u.s->p)
        OUT();

    /* Handle the 'w' flag. */
    if (cp->u.s->wfile && !pd) {
        if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
            O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 0666)) == -1)
            err(1, "%s", cp->u.s->wfile);
        if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
            write(cp->u.s->wfd, "\n", 1) != 1)
            err(1, "%s", cp->u.s->wfile);
    }
    return (1);
}

/*
 * do_tr --
 *  Perform translation ('y' command) in the pattern space.
 */
static void
do_tr(struct s_tr *y)
{
    SPACE tmp;
    char c, *p;
    size_t clen, left;
    int i;

    if (MB_CUR_MAX == 1) {
        /*
         * Single-byte encoding: perform in-place translation
         * of the pattern space.
         */
        for (p = ps; p < &ps[psl]; p++)
            *p = y->bytetab[(uchar_t)*p];
    } else {
        /*
         * Multi-byte encoding: perform translation into the
         * translation space, then swap the translation and
         * pattern spaces.
         */
        /* Clean translation space. */
        YS.len = 0;
        for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
            if ((c = y->bytetab[(uchar_t)*p]) != '\0') {
                cspace(&YS, &c, 1, APPEND);
                clen = 1;
                continue;
            }
            for (i = 0; i < y->nmultis; i++)
                if (left >= y->multis[i].fromlen &&
                    memcmp(p, y->multis[i].from,
                    y->multis[i].fromlen) == 0)
                    break;
            if (i < y->nmultis) {
                cspace(&YS, y->multis[i].to,
                    y->multis[i].tolen, APPEND);
                clen = y->multis[i].fromlen;
            } else {
                cspace(&YS, p, 1, APPEND);
                clen = 1;
            }
        }
        /* Swap the translation space and the pattern space. */
        tmp = PS;
        PS = YS;
        YS = tmp;
        YS.space = YS.back;
    }
}

/*
 * Flush append requests.  Always called before reading a line,
 * therefore it also resets the substitution done (sdone) flag.
 */
static void
flush_appends(void)
{
    FILE *f;
    int count, i;
    char buf[8 * 1024];

    for (i = 0; i < appendx; i++)
        switch (appends[i].type) {
        case AP_STRING:
            (void) fwrite(appends[i].s, sizeof (char),
                appends[i].len, outfile);
            break;
        case AP_FILE:
            /*
             * Read files probably shouldn't be cached.  Since
             * it's not an error to read a non-existent file,
             * it's possible that another program is interacting
             * with the sed script through the filesystem.  It
             * would be truly bizarre, but possible.  It's probably
             * not that big a performance win, anyhow.
             */
            if ((f = fopen(appends[i].s, "r")) == NULL)
                break;
            while ((count =
                fread(buf, sizeof (char), sizeof (buf), f)))
                (void) fwrite(buf, sizeof (char), count,
                    outfile);
            (void) fclose(f);
            break;
        }
    if (ferror(outfile))
        errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
    appendx = sdone = 0;
}

static void
lputs(char *s, size_t len)
{
    static const char escapes[] = "\\\a\b\f\r\t\v";
    int c, col, width;
    const char *p;
    struct winsize win;
    static int termwidth = -1;
    size_t clen, i;
    wchar_t wc;
    mbstate_t mbs;

    if (outfile != stdout)
        termwidth = 60;
    if (termwidth == -1) {
        if (((p = getenv("COLUMNS")) != NULL) && (*p != '\0'))
            termwidth = atoi(p);
        else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
            win.ws_col > 0)
            termwidth = win.ws_col;
        else
            termwidth = 60;
    }
    if (termwidth <= 0)
        termwidth = 1;

    (void) memset(&mbs, 0, sizeof (mbs));
    col = 0;
    while (len != 0) {
        clen = mbrtowc(&wc, s, len, &mbs);
        if (clen == 0)
            clen = 1;
        if (clen == (size_t)-1 || clen == (size_t)-2) {
            wc = (unsigned char)*s;
            clen = 1;
            (void) memset(&mbs, 0, sizeof (mbs));
        }
        if (wc == '\n') {
            if (col + 1 >= termwidth)
                (void) fprintf(outfile, "\\\n");
            (void) fputc('$', outfile);
            (void) fputc('\n', outfile);
            col = 0;
        } else if (iswprint(wc)) {
            width = wcwidth(wc);
            if (col + width >= termwidth) {
                (void) fprintf(outfile, "\\\n");
                col = 0;
            }
            (void) fwrite(s, 1, clen, outfile);
            col += width;
        } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
            (p = strchr(escapes, c)) != NULL) {
            if (col + 2 >= termwidth) {
                (void) fprintf(outfile, "\\\n");
                col = 0;
            }
            (void) fprintf(outfile, "\\%c",
                "\\abfrtv"[(uintptr_t)p - (uintptr_t)escapes]);
            col += 2;
        } else {
            if (col + 4 * clen >= (unsigned)termwidth) {
                (void) fprintf(outfile, "\\\n");
                col = 0;
            }
            for (i = 0; i < clen; i++)
                (void) fprintf(outfile, "\\%03o",
                    (int)(unsigned char)s[i]);
            col += 4 * clen;
        }
        s += clen;
        len -= clen;
    }
    if (col + 1 >= termwidth)
        (void) fprintf(outfile, "\\\n");
    (void) fputc('$', outfile);
    (void) fputc('\n', outfile);
    if (ferror(outfile))
        errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
}

static int
regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
    size_t slen)
{
    int eval;

    if (preg == NULL) {
        if (defpreg == NULL)
            fatal(_("first RE may not be empty"));
    } else
        defpreg = preg;

    /* Set anchors */
    match[0].rm_so = 0;
    match[0].rm_eo = slen;

    eval = regexec(defpreg, string,
        nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
    switch (eval) {
    case 0:
        return (1);
    case REG_NOMATCH:
        return (0);
    }
    fatal(_("RE error: %s"), strregerror(eval, defpreg));
    return (0);
}

/*
 * regsub - perform substitutions after a regexp match
 * Based on a routine by Henry Spencer
 */
static void
regsub(SPACE *sp, char *string, char *src)
{
    int len, no;
    char c, *dst;

#define NEEDSP(reqlen)                          \
    /* XXX What is the +1 for? */                   \
    if (sp->len + (reqlen) + 1 >= sp->blen) {           \
        sp->blen += (reqlen) + 1024;                \
        if ((sp->back = realloc(sp->back, sp->blen)) == NULL)   \
            err(1, "realloc");              \
        sp->space = sp->back;                   \
        dst = sp->space + sp->len;              \
    }

    dst = sp->space + sp->len;
    while ((c = *src++) != '\0') {
        if (c == '&')
            no = 0;
        else if (c == '\\' && isdigit((unsigned char)*src))
            no = *src++ - '0';
        else
            no = -1;
        if (no < 0) {       /* Ordinary character. */
            if (c == '\\' && (*src == '\\' || *src == '&'))
                c = *src++;
            NEEDSP(1);
            *dst++ = c;
            ++sp->len;
        } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
            len = match[no].rm_eo - match[no].rm_so;
            NEEDSP(len);
            (void) memmove(dst, string + match[no].rm_so, len);
            dst += len;
            sp->len += len;
        }
    }
    NEEDSP(1);
    *dst = '\0';
}

/*
 * cspace --
 *  Concatenate space: append the source space to the destination space,
 *  allocating new space as necessary.
 */
void
cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
{
    size_t tlen;

    /* Make sure SPACE has enough memory and ramp up quickly. */
    tlen = sp->len + len + 1;
    if (tlen > sp->blen) {
        sp->blen = tlen + 1024;
        if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
            NULL)
            err(1, "realloc");
    }

    if (spflag == REPLACE)
        sp->len = 0;

    (void) memmove(sp->space + sp->len, p, len);

    sp->space[sp->len += len] = '\0';
}

/*
 * Close all cached opened files and report any errors
 */
void
cfclose(struct s_command *cp, struct s_command *end)
{

    for (; cp != end; cp = cp->next)
        switch (cp->code) {
        case 's':
            if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
                err(1, "%s", cp->u.s->wfile);
            cp->u.s->wfd = -1;
            break;
        case 'w':
            if (cp->u.fd != -1 && close(cp->u.fd))
                err(1, "%s", cp->t);
            cp->u.fd = -1;
            break;
        case '{':
            cfclose(cp->u.c, cp->next);
            break;
        }
}