2 * Copyright 1986, Larry Wall
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following condition is met:
6 * 1. Redistributions of source code must retain the above copyright notice,
7 * this condition and the following disclaimer.
9 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
10 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
11 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
12 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
13 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
14 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
15 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
16 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
17 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
18 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
21 * patch - a program to apply diffs to original files
23 * -C option added in 1998, original code by Marc Espie, based on FreeBSD
26 * $OpenBSD: patch.c,v 1.50 2012/05/15 19:32:02 millert Exp $
31 #include <sys/types.h>
46 #include "backupfile.h"
47 #include "pathnames.h"
49 mode_t filemode = 0644;
51 char *buf; /* general purpose buffer */
52 size_t buf_size; /* size of the general purpose buffer */
54 bool using_plan_a = true; /* try to keep everything in memory */
55 bool out_of_mem = false; /* ran out of memory in plan a */
59 char *filearg[MAXFILEC];
60 bool ok_to_create_file = false;
62 char *origprae = NULL;
67 bool toutkeep = false;
68 bool trejkeep = false;
69 bool warn_on_invalid_line;
70 bool last_line_missing_eol;
80 bool noreverse = false;
81 bool skip_rest_of_patch = false;
83 bool canonicalize = false;
84 bool check_only = false;
86 char *revision = NULL; /* prerequisite revision, if any */
87 LINENUM input_lines = 0; /* how long is input file in lines */
88 int posix = 0; /* strict POSIX mode? */
90 static void reinitialize_almost_everything(void);
91 static void get_some_switches(void);
92 static LINENUM locate_hunk(LINENUM);
93 static void abort_context_hunk(void);
94 static void rej_line(int, LINENUM);
95 static void abort_hunk(void);
96 static void apply_hunk(LINENUM);
97 static void init_output(const char *);
98 static void init_reject(const char *);
99 static void copy_till(LINENUM, bool);
100 static bool spew_output(void);
101 static void dump_line(LINENUM, bool);
102 static bool patch_match(LINENUM, LINENUM, LINENUM);
103 static bool similar(const char *, const char *, int);
104 static void usage(void);
106 /* true if -E was specified on command line. */
107 static bool remove_empty_files = false;
109 /* true if -R was specified on command line. */
110 static bool reverse_flag_specified = false;
112 /* buffer holding the name of the rejected patch file. */
113 static char rejname[NAME_MAX + 1];
115 /* how many input lines have been irretractibly output */
116 static LINENUM last_frozen_line = 0;
118 static int Argc; /* guess */
120 static int Argc_last; /* for restarting plan_b */
121 static char **Argv_last;
123 static FILE *ofp = NULL; /* output file pointer */
124 static FILE *rejfp = NULL; /* reject file pointer */
126 static int filec = 0; /* how many file arguments? */
127 static LINENUM last_offset = 0;
128 static LINENUM maxfuzz = 2;
130 /* patch using ifdef, ifndef, etc. */
131 static bool do_defines = false;
133 static char if_defined[128];
135 static char not_defined[128];
137 static const char else_defined[] = "#else\n";
139 static char end_defined[128];
142 /* Apply a set of diffs as appropriate. */
145 main(int argc, char *argv[])
147 int error = 0, hunk, failed, i, fd;
149 LINENUM where = 0, newwhere, fuzz, mymaxfuzz;
155 for (i = 0; i < MAXFILEC; i++)
158 buf_size = INITLINELEN;
159 buf = malloc((unsigned)(buf_size));
161 fatal("out of memory\n");
163 /* Cons up the names of the temporary files. */
164 if ((tmpdir = getenv("TMPDIR")) == NULL || *tmpdir == '\0')
166 for (i = strlen(tmpdir) - 1; i > 0 && tmpdir[i] == '/'; i--)
169 if (asprintf(&TMPOUTNAME, "%.*s/patchoXXXXXXXXXX", i, tmpdir) == -1)
170 fatal("cannot allocate memory");
171 if ((fd = mkstemp(TMPOUTNAME)) < 0)
172 pfatal("can't create %s", TMPOUTNAME);
175 if (asprintf(&TMPINNAME, "%.*s/patchiXXXXXXXXXX", i, tmpdir) == -1)
176 fatal("cannot allocate memory");
177 if ((fd = mkstemp(TMPINNAME)) < 0)
178 pfatal("can't create %s", TMPINNAME);
181 if (asprintf(&TMPREJNAME, "%.*s/patchrXXXXXXXXXX", i, tmpdir) == -1)
182 fatal("cannot allocate memory");
183 if ((fd = mkstemp(TMPREJNAME)) < 0)
184 pfatal("can't create %s", TMPREJNAME);
187 if (asprintf(&TMPPATNAME, "%.*s/patchpXXXXXXXXXX", i, tmpdir) == -1)
188 fatal("cannot allocate memory");
189 if ((fd = mkstemp(TMPPATNAME)) < 0)
190 pfatal("can't create %s", TMPPATNAME);
193 v = getenv("SIMPLE_BACKUP_SUFFIX");
195 simple_backup_suffix = v;
197 simple_backup_suffix = ORIGEXT;
204 if (backup_type == none) {
205 if ((v = getenv("PATCH_VERSION_CONTROL")) == NULL)
206 v = getenv("VERSION_CONTROL");
207 if (v != NULL || !posix)
208 backup_type = get_version(v); /* OK to pass NULL. */
211 /* make sure we clean up /tmp in case of disaster */
215 for (open_patch_file(filearg[1]); there_is_another_patch();
216 reinitialize_almost_everything()) {
217 /* for each patch in patch file */
221 warn_on_invalid_line = true;
224 outname = savestr(filearg[0]);
226 /* for ed script just up and do it and exit */
227 if (diff_type == ED_DIFF) {
231 /* initialize the patched file */
232 if (!skip_rest_of_patch)
233 init_output(TMPOUTNAME);
235 /* initialize reject file */
236 init_reject(TMPREJNAME);
238 /* find out where all the lines are */
239 if (!skip_rest_of_patch)
240 scan_input(filearg[0]);
242 /* from here on, open no standard i/o files, because malloc */
243 /* might misfire and we can't catch it easily */
245 /* apply each hunk of patch */
249 while (another_hunk()) {
252 mymaxfuzz = pch_context();
253 if (maxfuzz < mymaxfuzz)
255 if (!skip_rest_of_patch) {
257 where = locate_hunk(fuzz);
258 if (hunk == 1 && where == 0 && !force) {
259 /* dwim for reversed patch? */
262 say("Not enough memory to try swapped hunk! Assuming unswapped.\n");
267 where = locate_hunk(fuzz);
269 /* didn't find it swapped */
271 /* put it back to normal */
272 fatal("lost hunk on alloc error!\n");
274 } else if (noreverse) {
276 /* put it back to normal */
277 fatal("lost hunk on alloc error!\n");
279 say("Ignoring previously applied (or reversed) patch.\n");
280 skip_rest_of_patch = true;
283 say("%seversed (or previously applied) patch detected! %s -R.",
284 reverse ? "R" : "Unr",
285 reverse ? "Assuming" : "Ignoring");
287 ask("%seversed (or previously applied) patch detected! %s -R? [y] ",
288 reverse ? "R" : "Unr",
289 reverse ? "Assume" : "Ignore");
291 ask("Apply anyway? [n] ");
293 skip_rest_of_patch = true;
297 /* put it back to normal */
298 fatal("lost hunk on alloc error!\n");
302 } while (!skip_rest_of_patch && where == 0 &&
303 ++fuzz <= mymaxfuzz);
305 if (skip_rest_of_patch) { /* just got decided */
306 if (ferror(ofp) || fclose(ofp)) {
307 say("Error writing %s\n",
314 newwhere = pch_newfirst() + last_offset;
315 if (skip_rest_of_patch) {
319 say("Hunk #%d ignored at %ld.\n",
321 } else if (where == 0) {
325 say("Hunk #%d failed at %ld.\n",
330 say("Hunk #%d succeeded at %ld",
333 say(" with fuzz %ld", fuzz);
335 say(" (offset %ld line%s)",
337 last_offset == 1L ? "" : "s");
343 if (out_of_mem && using_plan_a) {
346 say("\n\nRan out of memory using Plan A--trying again...\n\n");
356 fatal("Internal error: hunk should not be 0\n");
358 /* finish spewing out the new file */
359 if (!skip_rest_of_patch && !spew_output()) {
360 say("Can't write %s\n", TMPOUTNAME);
364 /* and put the output where desired */
366 if (!skip_rest_of_patch) {
368 char *realout = outname;
371 if (move_file(TMPOUTNAME, outname) < 0) {
373 realout = TMPOUTNAME;
374 chmod(TMPOUTNAME, filemode);
376 chmod(outname, filemode);
378 if (remove_empty_files &&
379 stat(realout, &statbuf) == 0 &&
380 statbuf.st_size == 0) {
382 say("Removing %s (empty after patching).\n",
388 if (ferror(rejfp) || fclose(rejfp)) {
389 say("Error writing %s\n", rejname);
395 if (*rejname == '\0') {
396 if (strlcpy(rejname, outname,
397 sizeof(rejname)) >= sizeof(rejname))
398 fatal("filename %s is too long\n", outname);
399 if (strlcat(rejname, REJEXT,
400 sizeof(rejname)) >= sizeof(rejname))
401 fatal("filename %s is too long\n", outname);
404 say("%d out of %d hunks %s--saving rejects to %s\n",
405 failed, hunk, skip_rest_of_patch ? "ignored" : "failed", rejname);
407 say("%d out of %d hunks %s\n",
408 failed, hunk, skip_rest_of_patch ? "ignored" : "failed");
409 if (!check_only && move_file(TMPREJNAME, rejname) < 0)
422 /* Prepare to find the next patch to do in the patch file. */
425 reinitialize_almost_everything(void)
431 last_frozen_line = 0;
448 reverse = reverse_flag_specified;
449 skip_rest_of_patch = false;
454 /* Process switches and filenames. */
457 get_some_switches(void)
459 const char *options = "b::B:cCd:D:eEfF:i:lnNo:p:r:RstuvV:x:z:";
460 static struct option longopts[] = {
461 {"backup", no_argument, 0, 'b'},
462 {"batch", no_argument, 0, 't'},
463 {"check", no_argument, 0, 'C'},
464 {"context", no_argument, 0, 'c'},
465 {"debug", required_argument, 0, 'x'},
466 {"directory", required_argument, 0, 'd'},
467 {"ed", no_argument, 0, 'e'},
468 {"force", no_argument, 0, 'f'},
469 {"forward", no_argument, 0, 'N'},
470 {"fuzz", required_argument, 0, 'F'},
471 {"ifdef", required_argument, 0, 'D'},
472 {"input", required_argument, 0, 'i'},
473 {"ignore-whitespace", no_argument, 0, 'l'},
474 {"normal", no_argument, 0, 'n'},
475 {"output", required_argument, 0, 'o'},
476 {"prefix", required_argument, 0, 'B'},
477 {"quiet", no_argument, 0, 's'},
478 {"reject-file", required_argument, 0, 'r'},
479 {"remove-empty-files", no_argument, 0, 'E'},
480 {"reverse", no_argument, 0, 'R'},
481 {"silent", no_argument, 0, 's'},
482 {"strip", required_argument, 0, 'p'},
483 {"suffix", required_argument, 0, 'z'},
484 {"unified", no_argument, 0, 'u'},
485 {"version", no_argument, 0, 'v'},
486 {"version-control", required_argument, 0, 'V'},
487 {"posix", no_argument, &posix, 1},
497 optreset = optind = 1;
498 while ((ch = getopt_long(Argc, Argv, options, longopts, NULL)) != -1) {
501 if (backup_type == none)
502 backup_type = numbered_existing;
506 say("Warning, the ``-b suffix'' option has been"
507 " obsoleted by the -z option.\n");
510 /* must directly follow 'b' case for backwards compat */
511 simple_backup_suffix = savestr(optarg);
514 origprae = savestr(optarg);
517 diff_type = CONTEXT_DIFF;
523 if (chdir(optarg) < 0)
524 pfatal("can't cd to %s", optarg);
528 if (!isalpha((unsigned char)*optarg) && *optarg != '_')
529 fatal("argument to -D is not an identifier\n");
530 snprintf(if_defined, sizeof if_defined,
531 "#ifdef %s\n", optarg);
532 snprintf(not_defined, sizeof not_defined,
533 "#ifndef %s\n", optarg);
534 snprintf(end_defined, sizeof end_defined,
535 "#endif /* %s */\n", optarg);
541 remove_empty_files = true;
547 maxfuzz = atoi(optarg);
550 if (++filec == MAXFILEC)
551 fatal("too many file arguments\n");
552 filearg[filec] = savestr(optarg);
558 diff_type = NORMAL_DIFF;
564 outname = savestr(optarg);
567 strippath = atoi(optarg);
570 if (strlcpy(rejname, optarg,
571 sizeof(rejname)) >= sizeof(rejname))
572 fatal("argument for -r is too long\n");
576 reverse_flag_specified = true;
585 diff_type = UNI_DIFF;
591 backup_type = get_version(optarg);
595 debug = atoi(optarg);
608 filearg[0] = savestr(*Argv++);
611 if (++filec == MAXFILEC)
612 fatal("too many file arguments\n");
613 filearg[filec] = savestr(*Argv++);
618 if (getenv("POSIXLY_CORRECT") != NULL)
626 "usage: patch [-bCcEeflNnRstuv] [-B backup-prefix] [-D symbol] [-d directory]\n"
627 " [-F max-fuzz] [-i patchfile] [-o out-file] [-p strip-count]\n"
628 " [-r rej-name] [-V t | nil | never] [-x number] [-z backup-ext]\n"
629 " [--posix] [origfile [patchfile]]\n"
630 " patch <patchfile\n");
631 my_exit(EXIT_SUCCESS);
635 * Attempt to find the right place to apply this hunk of patch.
638 locate_hunk(LINENUM fuzz)
640 LINENUM first_guess = pch_first() + last_offset;
642 LINENUM pat_lines = pch_ptrn_lines();
643 LINENUM max_pos_offset = input_lines - first_guess - pat_lines + 1;
644 LINENUM max_neg_offset = first_guess - last_frozen_line - 1 + pch_context();
646 if (pat_lines == 0) { /* null range matches always */
647 if (verbose && fuzz == 0 && (diff_type == CONTEXT_DIFF
648 || diff_type == NEW_CONTEXT_DIFF
649 || diff_type == UNI_DIFF)) {
650 say("Empty context always matches.\n");
652 return (first_guess);
654 if (max_neg_offset >= first_guess) /* do not try lines < 0 */
655 max_neg_offset = first_guess - 1;
656 if (first_guess <= input_lines && patch_match(first_guess, 0, fuzz))
658 for (offset = 1; ; offset++) {
659 bool check_after = (offset <= max_pos_offset);
660 bool check_before = (offset <= max_neg_offset);
662 if (check_after && patch_match(first_guess, offset, fuzz)) {
665 say("Offset changing from %ld to %ld\n",
666 last_offset, offset);
668 last_offset = offset;
669 return first_guess + offset;
670 } else if (check_before && patch_match(first_guess, -offset, fuzz)) {
673 say("Offset changing from %ld to %ld\n",
674 last_offset, -offset);
676 last_offset = -offset;
677 return first_guess - offset;
678 } else if (!check_before && !check_after)
683 /* We did not find the pattern, dump out the hunk so they can handle it. */
686 abort_context_hunk(void)
689 const LINENUM pat_end = pch_end();
691 * add in last_offset to guess the same as the previous successful
694 const LINENUM oldfirst = pch_first() + last_offset;
695 const LINENUM newfirst = pch_newfirst() + last_offset;
696 const LINENUM oldlast = oldfirst + pch_ptrn_lines() - 1;
697 const LINENUM newlast = newfirst + pch_repl_lines() - 1;
698 const char *stars = (diff_type >= NEW_CONTEXT_DIFF ? " ****" : "");
699 const char *minuses = (diff_type >= NEW_CONTEXT_DIFF ? " ----" : " -----");
701 fprintf(rejfp, "***************\n");
702 for (i = 0; i <= pat_end; i++) {
703 switch (pch_char(i)) {
705 if (oldlast < oldfirst)
706 fprintf(rejfp, "*** 0%s\n", stars);
707 else if (oldlast == oldfirst)
708 fprintf(rejfp, "*** %ld%s\n", oldfirst, stars);
710 fprintf(rejfp, "*** %ld,%ld%s\n", oldfirst,
714 if (newlast < newfirst)
715 fprintf(rejfp, "--- 0%s\n", minuses);
716 else if (newlast == newfirst)
717 fprintf(rejfp, "--- %ld%s\n", newfirst, minuses);
719 fprintf(rejfp, "--- %ld,%ld%s\n", newfirst,
723 fprintf(rejfp, "%s", pfetch(i));
729 fprintf(rejfp, "%c %s", pch_char(i), pfetch(i));
732 fatal("fatal internal error in abort_context_hunk\n");
738 rej_line(int ch, LINENUM i)
741 const char *line = pfetch(i);
745 fprintf(rejfp, "%c%s", ch, line);
746 if (len == 0 || line[len-1] != '\n')
747 fprintf(rejfp, "\n\\ No newline at end of file\n");
755 const LINENUM pat_end = pch_end();
756 const LINENUM oldfirst = pch_first() + last_offset;
757 const LINENUM newfirst = pch_newfirst() + last_offset;
759 if (diff_type != UNI_DIFF) {
760 abort_context_hunk();
764 for (i = 0; i <= pat_end; i++) {
765 if (pch_char(i) == '=') {
771 fprintf(rejfp, "malformed hunk: no split found\n");
776 fprintf(rejfp, "@@ -%ld,%ld +%ld,%ld @@\n",
777 pch_ptrn_lines() ? oldfirst : 0,
778 pch_ptrn_lines(), newfirst, pch_repl_lines());
779 while (i < split || j <= pat_end) {
780 ch1 = i < split ? pch_char(i) : -1;
781 ch2 = j <= pat_end ? pch_char(j) : -1;
785 } else if (ch1 == ' ' && ch2 == ' ') {
789 } else if (ch1 == '!' && ch2 == '!') {
790 while (i < split && ch1 == '!') {
793 ch1 = i < split ? pch_char(i) : -1;
795 while (j <= pat_end && ch2 == '!') {
798 ch2 = j <= pat_end ? pch_char(j) : -1;
800 } else if (ch1 == '*') {
802 } else if (ch2 == '+' || ch2 == ' ') {
806 fprintf(rejfp, "internal error on (%ld %ld %ld)\n",
815 /* We found where to apply it (we hope), so do it. */
818 apply_hunk(LINENUM where)
821 const LINENUM lastline = pch_ptrn_lines();
822 LINENUM new = lastline + 1;
827 int def_state = OUTSIDE;
828 const LINENUM pat_end = pch_end();
831 while (pch_char(new) == '=' || pch_char(new) == '\n')
834 while (old <= lastline) {
835 if (pch_char(old) == '-') {
836 copy_till(where + old - 1, false);
838 if (def_state == OUTSIDE) {
839 fputs(not_defined, ofp);
840 def_state = IN_IFNDEF;
841 } else if (def_state == IN_IFDEF) {
842 fputs(else_defined, ofp);
845 fputs(pfetch(old), ofp);
849 } else if (new > pat_end) {
851 } else if (pch_char(new) == '+') {
852 copy_till(where + old - 1, false);
854 if (def_state == IN_IFNDEF) {
855 fputs(else_defined, ofp);
857 } else if (def_state == OUTSIDE) {
858 fputs(if_defined, ofp);
859 def_state = IN_IFDEF;
862 fputs(pfetch(new), ofp);
864 } else if (pch_char(new) != pch_char(old)) {
865 say("Out-of-sync patch, lines %ld,%ld--mangled text or line numbers, maybe?\n",
866 pch_hunk_beg() + old,
867 pch_hunk_beg() + new);
869 say("oldchar = '%c', newchar = '%c'\n",
870 pch_char(old), pch_char(new));
873 } else if (pch_char(new) == '!') {
874 copy_till(where + old - 1, false);
876 fputs(not_defined, ofp);
877 def_state = IN_IFNDEF;
879 while (pch_char(old) == '!') {
881 fputs(pfetch(old), ofp);
887 fputs(else_defined, ofp);
890 while (pch_char(new) == '!') {
891 fputs(pfetch(new), ofp);
895 if (pch_char(new) != ' ')
896 fatal("Internal error: expected ' '\n");
899 if (do_defines && def_state != OUTSIDE) {
900 fputs(end_defined, ofp);
905 if (new <= pat_end && pch_char(new) == '+') {
906 copy_till(where + old - 1, false);
908 if (def_state == OUTSIDE) {
909 fputs(if_defined, ofp);
910 def_state = IN_IFDEF;
911 } else if (def_state == IN_IFNDEF) {
912 fputs(else_defined, ofp);
916 while (new <= pat_end && pch_char(new) == '+') {
917 fputs(pfetch(new), ofp);
921 if (do_defines && def_state != OUTSIDE) {
922 fputs(end_defined, ofp);
930 init_output(const char *name)
932 ofp = fopen(name, "w");
934 pfatal("can't create %s", name);
938 * Open a file to put hunks we can't locate.
941 init_reject(const char *name)
943 rejfp = fopen(name, "w");
945 pfatal("can't create %s", name);
949 * Copy input file to output, up to wherever hunk is to be applied.
950 * If endoffile is true, treat the last line specially since it may
954 copy_till(LINENUM lastline, bool endoffile)
956 if (last_frozen_line > lastline)
957 fatal("misordered hunks! output would be garbled\n");
958 while (last_frozen_line < lastline) {
959 if (++last_frozen_line == lastline && endoffile)
960 dump_line(last_frozen_line, !last_line_missing_eol);
962 dump_line(last_frozen_line, true);
967 * Finish copying the input file to the output file.
976 say("il=%ld lfl=%ld\n", input_lines, last_frozen_line);
979 copy_till(input_lines, true); /* dump remainder of file */
980 rv = ferror(ofp) == 0 && fclose(ofp) == 0;
986 * Copy one line from input to output.
989 dump_line(LINENUM line, bool write_newline)
996 /* Note: string is not NUL terminated. */
997 for (; *s != '\n'; s++)
1004 * Does the patch pattern match at line base+offset?
1007 patch_match(LINENUM base, LINENUM offset, LINENUM fuzz)
1009 LINENUM pline = 1 + fuzz;
1011 LINENUM pat_lines = pch_ptrn_lines() - fuzz;
1012 const char *ilineptr;
1013 const char *plineptr;
1016 for (iline = base + offset + fuzz; pline <= pat_lines; pline++, iline++) {
1017 ilineptr = ifetch(iline, offset >= 0);
1018 if (ilineptr == NULL)
1020 plineptr = pfetch(pline);
1021 plinelen = pch_line_len(pline);
1023 if (!similar(ilineptr, plineptr, plinelen))
1025 } else if (strnNE(ilineptr, plineptr, plinelen))
1027 if (iline == input_lines) {
1029 * We are looking at the last line of the file.
1030 * If the file has no eol, the patch line should
1031 * not have one either and vice-versa. Note that
1034 if (last_line_missing_eol) {
1035 if (plineptr[plinelen - 1] == '\n')
1038 if (plineptr[plinelen - 1] != '\n')
1047 * Do two lines match with canonicalized white space?
1050 similar(const char *a, const char *b, int len)
1053 if (isspace((unsigned char)*b)) { /* whitespace (or \n) to match? */
1054 if (!isspace((unsigned char)*a)) /* no corresponding whitespace? */
1056 while (len && isspace((unsigned char)*b) && *b != '\n')
1057 b++, len--; /* skip pattern whitespace */
1058 while (isspace((unsigned char)*a) && *a != '\n')
1059 a++; /* skip target whitespace */
1060 if (*a == '\n' || *b == '\n')
1061 return (*a == *b); /* should end in sync */
1062 } else if (*a++ != *b++) /* match non-whitespace chars */
1065 len--; /* probably not necessary */
1067 return true; /* actually, this is not reached */
1068 /* since there is always a \n */