xref: /src/usr.bin/patch/patch.c

/*	$NetBSD: patch.c,v 1.17 2003/05/30 23:08:13 kristerw Exp $	*/

/* patch - a program to apply diffs to original files
 *
 * Copyright 1986, Larry Wall
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following condition
 * is met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this condition and the following disclaimer.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: patch.c,v 1.17 2003/05/30 23:08:13 kristerw Exp $");
#endif /* not lint */

#include "INTERN.h"
#include "common.h"
#include "EXTERN.h"
#include "version.h"
#include "util.h"
#include "pch.h"
#include "inp.h"
#include "backupfile.h"

#include <stdlib.h>
#include <unistd.h>

/* procedures */
static void reinitialize_almost_everything(void);
static char *nextarg(void);
static int optcmp(const void *, const void *);
static char decode_long_option(char *);
static void get_some_switches(void);
static LINENUM locate_hunk(LINENUM);
static void abort_hunk(void);
static void apply_hunk(LINENUM);
static void init_output(char *);
static void init_reject(char *);
static void copy_till(LINENUM);
static void spew_output(void);
static void dump_line(LINENUM);
static bool patch_match(LINENUM, LINENUM, LINENUM);
static bool similar(char *, char *, size_t);
int main(int, char *[]);

/* TRUE if -E was specified on command line.  */
static int remove_empty_files = FALSE;

/* TRUE if -R was specified on command line.  */
static int reverse_flag_specified = FALSE;

/* Apply a set of diffs as appropriate. */

int
main(int argc, char *argv[])
{
    LINENUM where = 0;
    LINENUM newwhere;
    LINENUM fuzz;
    LINENUM mymaxfuzz;
    int hunk = 0;
    int failed = 0;
    int failtotal = 0;
    int i;

    for (i = 0; i<MAXFILEC; i++)
	filearg[i] = NULL;

    myuid = getuid();

    /* Cons up the names of the temporary files.  */
    {
      /* Directory for temporary files.  */
      char *tmpdir;
      size_t tmpname_len;

      tmpdir = getenv ("TMPDIR");
      if (tmpdir == NULL) {
	tmpdir = "/tmp";
      }
      tmpname_len = strlen (tmpdir) + 20;

      TMPOUTNAME = xmalloc(tmpname_len);
      strcpy (TMPOUTNAME, tmpdir);
      strcat (TMPOUTNAME, "/patchoXXXXXX");
      if ((i = mkstemp(TMPOUTNAME)) < 0)
        pfatal("can't create %s", TMPOUTNAME);
      Close(i);

      TMPINNAME = xmalloc(tmpname_len);
      strcpy (TMPINNAME, tmpdir);
      strcat (TMPINNAME, "/patchiXXXXXX");
      if ((i = mkstemp(TMPINNAME)) < 0)
        pfatal("can't create %s", TMPINNAME);
      Close(i);

      TMPREJNAME = xmalloc(tmpname_len);
      strcpy (TMPREJNAME, tmpdir);
      strcat (TMPREJNAME, "/patchrXXXXXX");
      if ((i = mkstemp(TMPREJNAME)) < 0)
        pfatal("can't create %s", TMPREJNAME);
      Close(i);

      TMPPATNAME = xmalloc(tmpname_len);
      strcpy (TMPPATNAME, tmpdir);
      strcat (TMPPATNAME, "/patchpXXXXXX");
      if ((i = mkstemp(TMPPATNAME)) < 0)
        pfatal("can't create %s", TMPPATNAME);
      Close(i);
    }

    {
      char *v;

      v = getenv ("SIMPLE_BACKUP_SUFFIX");
      if (v)
	simple_backup_suffix = v;
      else
	simple_backup_suffix = ORIGEXT;
#ifndef NODIR
      v = getenv ("VERSION_CONTROL");
      backup_type = get_version (v); /* OK to pass NULL. */
#endif
    }

    /* parse switches */
    Argc = argc;
    Argv = argv;
    get_some_switches();

    /* make sure we clean up /tmp in case of disaster */
    set_signals(0);

    for (
	open_patch_file(filearg[1]);
	there_is_another_patch();
	reinitialize_almost_everything()
    ) {					/* for each patch in patch file */

	if (!skip_rest_of_patch && outname == NULL)
	    outname = xstrdup(filearg[0]);

	/* for ed script just up and do it and exit */
	if (diff_type == ED_DIFF) {
	    do_ed_script();
	    continue;
	}

	/* initialize the patched file */
	if (!skip_rest_of_patch)
	    init_output(TMPOUTNAME);

	/* initialize reject file */
	init_reject(TMPREJNAME);

	/* find out where all the lines are */
	if (!skip_rest_of_patch)
	    scan_input(filearg[0]);

	/* from here on, open no standard i/o files, because malloc */
	/* might misfire and we can't catch it easily */

	/* apply each hunk of patch */
	hunk = 0;
	failed = 0;
	while (another_hunk()) {
	    hunk++;
	    fuzz = Nulline;
	    mymaxfuzz = pch_context();
	    if (maxfuzz < mymaxfuzz)
		mymaxfuzz = maxfuzz;
	    if (!skip_rest_of_patch) {
		do {
		    where = locate_hunk(fuzz);
		    if (hunk == 1 && where == Nulline && !force) {
						/* dwim for reversed patch? */
			if (!pch_swap()) {
			    if (fuzz == Nulline)
				say(
"Not enough memory to try swapped hunk!  Assuming unswapped.\n");
			    continue;
			}
			reverse = !reverse;
			where = locate_hunk(fuzz);  /* try again */
			if (where == Nulline) {	    /* didn't find it swapped */
			    if (!pch_swap())         /* put it back to normal */
				fatal("lost hunk on alloc error!\n");
			    reverse = !reverse;
			}
			else if (noreverse) {
			    if (!pch_swap())         /* put it back to normal */
				fatal("lost hunk on alloc error!\n");
			    reverse = !reverse;
			    say(
"Ignoring previously applied (or reversed) patch.\n");
			    skip_rest_of_patch = TRUE;
			}
			else if (batch) {
			    if (verbose)
				say(
"%seversed (or previously applied) patch detected!  %s -R.",
				reverse ? "R" : "Unr",
				reverse ? "Assuming" : "Ignoring");
			}
			else {
			    ask(
"%seversed (or previously applied) patch detected!  %s -R? [y] ",
				reverse ? "R" : "Unr",
				reverse ? "Assume" : "Ignore");
			    if (*buf == 'n') {
				ask("Apply anyway? [n] ");
				if (*buf != 'y')
				    skip_rest_of_patch = TRUE;
				where = Nulline;
				reverse = !reverse;
				if (!pch_swap())  /* put it back to normal */
				    fatal("lost hunk on alloc error!\n");
			    }
			}
		    }
		} while (!skip_rest_of_patch && where == Nulline &&
		    ++fuzz <= mymaxfuzz);

		if (skip_rest_of_patch) {		/* just got decided */
		    Fclose(ofp);
		    ofp = NULL;
		}
	    }

	    newwhere = pch_newfirst() + last_offset;
	    if (skip_rest_of_patch) {
		abort_hunk();
		failed++;
		if (verbose)
		    say("Hunk #%d ignored at %d.\n", hunk, newwhere);
	    }
	    else if (where == Nulline) {
		abort_hunk();
		failed++;
		if (verbose)
		    say("Hunk #%d failed at %d.\n", hunk, newwhere);
	    }
	    else {
		apply_hunk(where);
		if (verbose) {
		    say("Hunk #%d succeeded at %d", hunk, newwhere);
		    if (fuzz)
			say(" with fuzz %d", fuzz);
		    if (last_offset)
			say(" (offset %d line%s)",
			    last_offset, last_offset==1?"":"s");
		    say(".\n");
		}
	    }
	}

	assert(hunk);

	/* finish spewing out the new file */
	if (!skip_rest_of_patch)
	    spew_output();

	/* and put the output where desired */
	ignore_signals();
	if (!skip_rest_of_patch) {
	    struct stat statbuf;
	    char *realout = outname;

	    if (move_file(TMPOUTNAME, outname) < 0) {
		toutkeep = TRUE;
		realout = TMPOUTNAME;
		chmod(TMPOUTNAME, filemode);
	    }
	    else
		chmod(outname, filemode);

	    if (remove_empty_files && stat(realout, &statbuf) == 0
		&& statbuf.st_size == 0) {
		if (verbose)
		    say("Removing %s (empty after patching).\n", realout);
	        while (unlink(realout) >= 0) ; /* while is for Eunice.  */
	    }
	}
	Fclose(rejfp);
	rejfp = NULL;
	if (failed) {
	    failtotal += failed;
	    if (outname != NULL) {
		    if (!*rejname) {
			    Strcpy(rejname, outname);
			    Strcat(rejname, REJEXT);
		    }
		    if (skip_rest_of_patch)
			    say("%d out of %d hunks ignored"
				"--saving rejects to %s\n",
				failed, hunk, rejname);
		    else
			    say("%d out of %d hunks failed"
				"--saving rejects to %s\n",
				failed, hunk, rejname);
		    if (move_file(TMPREJNAME, rejname) < 0)
			    trejkeep = TRUE;
	    } else
		    say("%d out of %d hunks ignored\n", failed, hunk);
	}
	set_signals(1);
    }
    my_exit(failtotal);
    /* NOTREACHED */
}

/* Prepare to find the next patch to do in the patch file. */

static void
reinitialize_almost_everything(void)
{
    re_patch();
    re_input();

    input_lines = 0;
    last_frozen_line = 0;

    filec = 0;
    if (filearg[0] != NULL) {
	free(filearg[0]);
	filearg[0] = NULL;
    }

    if (outname != NULL) {
	free(outname);
	outname = NULL;
    }

    last_offset = 0;

    diff_type = 0;

    if (revision != NULL) {
	free(revision);
	revision = NULL;
    }

    reverse = reverse_flag_specified;
    skip_rest_of_patch = FALSE;

    get_some_switches();

    if (filec >= 2)
	fatal("you may not change to a different patch file\n");
}

static char *
nextarg(void)
{
    if (!--Argc)
	fatal("missing argument after `%s'\n", *Argv);
    return *++Argv;
}

/* Module for handling of long options. */

struct option {
    char *long_opt;
    char short_opt;
};

static int
optcmp(const void *va, const void *vb)
{
    const struct option *a = va, *b = vb;
    return strcmp (a->long_opt, b->long_opt);
}

/* Decode Long options beginning with "--" to their short equivalents. */

static char
decode_long_option(char *opt)
{
    /*
     * This table must be sorted on the first field.  We also decode
     * unimplemented options as those will probably be dealt with
     * later, anyhow.
     */
    static struct option options[] = {
      { "batch",		't' },
      { "check",		'C' },
      { "context",		'c' },
      { "debug",		'x' },
      { "directory",		'd' },
      { "ed",			'e' },
      { "force",		'f' },
      { "forward",		'N' },
      { "fuzz",			'F' },
      { "ifdef",		'D' },
      { "ignore-whitespace",	'l' },
      { "normal",		'n' },
      { "output",		'o' },
      { "patchfile",		'i' },
      { "prefix",		'B' },
      { "quiet",		's' },
      { "reject-file",		'r' },
      { "remove-empty-files",	'E' },
      { "reverse",		'R' },
      { "silent",		's' },
      { "skip",			'S' },
      { "strip",		'p' },
      { "suffix",		'b' },
      { "unified",		'u' },
      { "version",		'v' },
      { "version-control",	'V' },
    };
    struct option key, *found;

    key.long_opt = opt;
    found = bsearch(&key, options,
	sizeof(options) / sizeof(options[0]), sizeof(options[0]), optcmp);

    return found ? found->short_opt : '\0';
}

/* Process switches and filenames up to next '+' or end of list. */

static void
get_some_switches(void)
{
    char *s;

    rejname[0] = '\0';
    if (!Argc)
	return;
    for (Argc--,Argv++; Argc; Argc--,Argv++) {
	s = Argv[0];
	if (strEQ(s, "+")) {
	    return;			/* + will be skipped by for loop */
	}
	if (*s != '-' || !s[1]) {
	    if (filec == MAXFILEC)
		fatal("too many file arguments\n");
	    if (filec == 1 && filearg[filec] != NULL)
		fatal("-i option and patchfile argument are mutually\
exclusive\n");
	    filearg[filec++] = xstrdup(s);
	}
	else {
	    char opt;

	    if (*(s + 1) == '-') {
		opt = decode_long_option(s + 2);
		s += strlen(s) - 1;
	    }
	    else
		opt = *++s;

	    switch (opt) {
	    case 'b':
		simple_backup_suffix = xstrdup(nextarg());
		break;
	    case 'B':
		origprae = xstrdup(nextarg());
		break;
	    case 'c':
		diff_type = CONTEXT_DIFF;
		break;
	    case 'd':
		if (!*++s)
		    s = nextarg();
		if (chdir(s) < 0)
		    pfatal("can't cd to %s", s);
		break;
	    case 'D':
	    	do_defines = TRUE;
		if (!*++s)
		    s = nextarg();
		if (!isalpha((unsigned char)*s) && '_' != *s)
		    fatal("argument to -D is not an identifier\n");
		Sprintf(if_defined, "#ifdef %s\n", s);
		Sprintf(not_defined, "#ifndef %s\n", s);
		Sprintf(end_defined, "#endif /* %s */\n", s);
		break;
	    case 'e':
		diff_type = ED_DIFF;
		break;
	    case 'E':
		remove_empty_files = TRUE;
		break;
	    case 'f':
		force = TRUE;
		break;
	    case 'F':
		if (*++s == '=')
		    s++;
		maxfuzz = atoi(s);
		break;
	    case 'i':
		if (filearg[1] != NULL)
		    free(filearg[1]);
		filearg[1] = xstrdup(nextarg());
		break;
	    case 'l':
		canonicalize = TRUE;
		break;
	    case 'n':
		diff_type = NORMAL_DIFF;
		break;
	    case 'N':
		noreverse = TRUE;
		break;
	    case 'o':
		outname = xstrdup(nextarg());
		break;
	    case 'p':
		if (*++s == '=')
		    s++;
		strippath = atoi(s);
		break;
	    case 'r':
		Strcpy(rejname, nextarg());
		break;
	    case 'R':
		reverse = TRUE;
		reverse_flag_specified = TRUE;
		break;
	    case 's':
		verbose = FALSE;
		break;
	    case 'S':
		skip_rest_of_patch = TRUE;
		break;
	    case 't':
		batch = TRUE;
		break;
	    case 'u':
		diff_type = UNI_DIFF;
		break;
	    case 'v':
		version();
		break;
	    case 'V':
#ifndef NODIR
		backup_type = get_version (nextarg ());
#endif
		break;
#ifdef DEBUGGING
	    case 'x':
		debug = atoi(s+1);
		break;
#endif
	    default:
		fprintf(stderr, "patch: unrecognized option `%s'\n", Argv[0]);
		fprintf(stderr, "\
Usage: patch [options] [origfile [patchfile]] [+ [options] [origfile]]...\n\
Options:\n\
       [-ceEflnNRsStuv] [-b backup-ext] [-B backup-prefix] [-d directory]\n\
       [-D symbol] [-Fmax-fuzz] [-o out-file] [-p[strip-count]]\n\
       [-r rej-name] [-V {numbered,existing,simple}]\n");
		my_exit(1);
	    }
	}
    }
}

/* Attempt to find the right place to apply this hunk of patch. */

static LINENUM
locate_hunk(LINENUM fuzz)
{
    LINENUM first_guess = pch_first() + last_offset;
    LINENUM offset;
    LINENUM pat_lines = pch_ptrn_lines();
    LINENUM max_pos_offset = input_lines - first_guess
				- pat_lines + 1;
    LINENUM max_neg_offset = first_guess - last_frozen_line - 1
				+ pch_context();

    if (!pat_lines)			/* null range matches always */
	return first_guess;
    if (max_neg_offset >= first_guess)	/* do not try lines < 0 */
	max_neg_offset = first_guess - 1;
    if (first_guess <= input_lines && patch_match(first_guess, Nulline, fuzz))
	return first_guess;
    for (offset = 1; ; offset++) {
	bool check_after = (offset <= max_pos_offset);
	bool check_before = (offset <= max_neg_offset);

	if (check_after && patch_match(first_guess, offset, fuzz)) {
#ifdef DEBUGGING
	    if (debug & 1)
		say("Offset changing from %d to %d\n", last_offset, offset);
#endif
	    last_offset = offset;
	    return first_guess+offset;
	}
	else if (check_before && patch_match(first_guess, -offset, fuzz)) {
#ifdef DEBUGGING
	    if (debug & 1)
		say("Offset changing from %d to %d\n", last_offset, -offset);
#endif
	    last_offset = -offset;
	    return first_guess-offset;
	}
	else if (!check_before && !check_after)
	    return Nulline;
    }
}

/* We did not find the pattern, dump out the hunk so they can handle it. */

static void
abort_hunk(void)
{
    LINENUM i;
    LINENUM pat_end = pch_end();
    /* add in last_offset to guess the same as the previous successful hunk */
    LINENUM oldfirst = pch_first() + last_offset;
    LINENUM newfirst = pch_newfirst() + last_offset;
    LINENUM oldlast = oldfirst + pch_ptrn_lines() - 1;
    LINENUM newlast = newfirst + pch_repl_lines() - 1;
    char *stars = (diff_type >= NEW_CONTEXT_DIFF ? " ****" : "");
    char *minuses = (diff_type >= NEW_CONTEXT_DIFF ? " ----" : " -----");

    fprintf(rejfp, "***************\n");
    for (i=0; i<=pat_end; i++) {
	switch (pch_char(i)) {
	case '*':
	    if (oldlast < oldfirst)
		fprintf(rejfp, "*** 0%s\n", stars);
	    else if (oldlast == oldfirst)
		fprintf(rejfp, "*** %d%s\n", oldfirst, stars);
	    else
		fprintf(rejfp, "*** %d,%d%s\n", oldfirst, oldlast, stars);
	    break;
	case '=':
	    if (newlast < newfirst)
		fprintf(rejfp, "--- 0%s\n", minuses);
	    else if (newlast == newfirst)
		fprintf(rejfp, "--- %d%s\n", newfirst, minuses);
	    else
		fprintf(rejfp, "--- %d,%d%s\n", newfirst, newlast, minuses);
	    break;
	case '\n':
	    fprintf(rejfp, "%s", pfetch(i));
	    break;
	case ' ': case '-': case '+': case '!':
	    fprintf(rejfp, "%c %s", pch_char(i), pfetch(i));
	    break;
	default:
	    fatal("fatal internal error in abort_hunk\n");
	}
    }
}

/* We found where to apply it (we hope), so do it. */

static void
apply_hunk(LINENUM where)
{
    LINENUM old = 1;
    LINENUM lastline = pch_ptrn_lines();
    LINENUM new = lastline+1;
#define OUTSIDE 0
#define IN_IFNDEF 1
#define IN_IFDEF 2
#define IN_ELSE 3
    int def_state = OUTSIDE;
    bool R_do_defines = do_defines;
    LINENUM pat_end = pch_end();

    where--;
    while (pch_char(new) == '=' || pch_char(new) == '\n')
	new++;

    while (old <= lastline) {
	if (pch_char(old) == '-') {
	    copy_till(where + old - 1);
	    if (R_do_defines) {
		if (def_state == OUTSIDE) {
		    fputs(not_defined, ofp);
		    def_state = IN_IFNDEF;
		}
		else if (def_state == IN_IFDEF) {
		    fputs(else_defined, ofp);
		    def_state = IN_ELSE;
		}
		fputs(pfetch(old), ofp);
	    }
	    last_frozen_line++;
	    old++;
	}
	else if (new > pat_end) {
	    break;
	}
	else if (pch_char(new) == '+') {
	    copy_till(where + old - 1);
	    if (R_do_defines) {
		if (def_state == IN_IFNDEF) {
		    fputs(else_defined, ofp);
		    def_state = IN_ELSE;
		}
		else if (def_state == OUTSIDE) {
		    fputs(if_defined, ofp);
		    def_state = IN_IFDEF;
		}
	    }
	    fputs(pfetch(new), ofp);
	    new++;
	}
	else if (pch_char(new) != pch_char(old)) {
	    say("Out-of-sync patch, lines %d,%d--mangled text or line numbers, maybe?\n",
		pch_hunk_beg() + old,
		pch_hunk_beg() + new);
#ifdef DEBUGGING
	    say("oldchar = '%c', newchar = '%c'\n",
		pch_char(old), pch_char(new));
#endif
	    my_exit(1);
	}
	else if (pch_char(new) == '!') {
	    copy_till(where + old - 1);
	    if (R_do_defines) {
	       fputs(not_defined, ofp);
	       def_state = IN_IFNDEF;
	    }
	    while (pch_char(old) == '!') {
		if (R_do_defines) {
		    fputs(pfetch(old), ofp);
		}
		last_frozen_line++;
		old++;
	    }
	    if (R_do_defines) {
		fputs(else_defined, ofp);
		def_state = IN_ELSE;
	    }
	    while (pch_char(new) == '!') {
		fputs(pfetch(new), ofp);
		new++;
	    }
	}
	else {
	    assert(pch_char(new) == ' ');
	    old++;
	    new++;
	    if (R_do_defines && def_state != OUTSIDE) {
		fputs(end_defined, ofp);
		def_state = OUTSIDE;
	    }
	}
    }
    if (new <= pat_end && pch_char(new) == '+') {
	copy_till(where + old - 1);
	if (R_do_defines) {
	    if (def_state == OUTSIDE) {
	    	fputs(if_defined, ofp);
		def_state = IN_IFDEF;
	    }
	    else if (def_state == IN_IFNDEF) {
		fputs(else_defined, ofp);
		def_state = IN_ELSE;
	    }
	}
	while (new <= pat_end && pch_char(new) == '+') {
	    fputs(pfetch(new), ofp);
	    new++;
	}
    }
    if (R_do_defines && def_state != OUTSIDE) {
	fputs(end_defined, ofp);
    }
}

/* Open the new file. */

static void
init_output(char *name)
{
    ofp = fopen(name, "w");
    if (ofp == NULL)
	pfatal("can't create %s", name);
}

/* Open a file to put hunks we can't locate. */

static void
init_reject(char *name)
{
    rejfp = fopen(name, "w");
    if (rejfp == NULL)
	pfatal("can't create %s", name);
}

/* Copy input file to output, up to wherever hunk is to be applied. */

static void
copy_till(LINENUM lastline)
{
    LINENUM R_last_frozen_line = last_frozen_line;

    if (R_last_frozen_line > lastline)
	fatal("misordered hunks! output would be garbled\n");
    while (R_last_frozen_line < lastline) {
	dump_line(++R_last_frozen_line);
    }
    last_frozen_line = R_last_frozen_line;
}

/* Finish copying the input file to the output file. */

static void
spew_output(void)
{
#ifdef DEBUGGING
    if (debug & 256)
	say("il=%d lfl=%d\n",input_lines,last_frozen_line);
#endif
    if (input_lines)
	copy_till(input_lines);		/* dump remainder of file */
    Fclose(ofp);
    ofp = NULL;
}

/* Copy one line from input to output. */

static void
dump_line(LINENUM line)
{
    char *s;
    char R_newline = '\n';

    /* Note: string is not null terminated. */
    for (s=ifetch(line); putc(*s, ofp) != R_newline; s++) ;
}

/* Does the patch pattern match at line base+offset? */

static bool
patch_match(LINENUM base, LINENUM offset, LINENUM fuzz)
{
    LINENUM pline = 1 + fuzz;
    LINENUM iline;
    LINENUM pat_lines = pch_ptrn_lines() - fuzz;

    for (iline=base+offset+fuzz; pline <= pat_lines; pline++,iline++) {
	if (canonicalize) {
	    if (!similar(ifetch(iline),
			 pfetch(pline),
			 pch_line_len(pline) ))
		return FALSE;
	}
	else if (strnNE(ifetch(iline),
		   pfetch(pline),
		   pch_line_len(pline) ))
	    return FALSE;
    }
    return TRUE;
}

/* Do two lines match with canonicalized white space? */

static bool
similar(char *a, char *b, size_t len)
{
    while (len) {
	if (isspace((unsigned char)*b)) {/* whitespace (or \n) to match? */
	    if (!isspace((unsigned char)*a))/* no corresponding whitespace? */
		return FALSE;
	    while (len && isspace((unsigned char)*b) && *b != '\n')
		b++,len--;		/* skip pattern whitespace */
	    while (isspace((unsigned char)*a) && *a != '\n')
		a++;			/* skip target whitespace */
	    if (*a == '\n' || *b == '\n')
		return (*a == *b);	/* should end in sync */
	}
	else if (*a++ != *b++)		/* match non-whitespace chars */
	    return FALSE;
	else
	    len--;			/* probably not necessary */
    }
    return TRUE;			/* actually, this is not reached */
					/* since there is always a \n */
}

/* Exit with cleanup. */

void
my_exit(int status)
{
    Unlink(TMPINNAME);
    if (!toutkeep) {
	Unlink(TMPOUTNAME);
    }
    if (!trejkeep) {
	Unlink(TMPREJNAME);
    }
    Unlink(TMPPATNAME);
    exit(status);
}