usr.bin/patch/pch.c

   1 /*-
   2  * Copyright 1986, Larry Wall
   3  *
   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.
   8  *
   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
  19  * SUCH DAMAGE.
  20  *
  21  * patch - a program to apply diffs to original files
  22  *
  23  * -C option added in 1998, original code by Marc Espie, based on FreeBSD
  24  * behaviour
  25  *
  26  * $OpenBSD: pch.c,v 1.43 2014/11/18 17:03:35 tobias Exp $
  27  * $FreeBSD$
  28  */
  29
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32
  33 #include <ctype.h>
  34 #include <libgen.h>
  35 #include <limits.h>
  36 #include <stdint.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "common.h"
  43 #include "util.h"
  44 #include "pch.h"
  45 #include "pathnames.h"
  46
  47 /* Patch (diff listing) abstract type. */
  48
  49 static off_t    p_filesize;     /* size of the patch file */
  50 static LINENUM  p_first;        /* 1st line number */
  51 static LINENUM  p_newfirst;     /* 1st line number of replacement */
  52 static LINENUM  p_ptrn_lines;   /* # lines in pattern */
  53 static LINENUM  p_repl_lines;   /* # lines in replacement text */
  54 static LINENUM  p_end = -1;     /* last line in hunk */
  55 static LINENUM  p_max;          /* max allowed value of p_end */
  56 static LINENUM  p_context = 3;  /* # of context lines */
  57 static LINENUM  p_input_line = 0;       /* current line # from patch file */
  58 static char     **p_line = NULL;/* the text of the hunk */
  59 static unsigned short   *p_len = NULL; /* length of each line */
  60 static char     *p_char = NULL; /* +, -, and ! */
  61 static int      hunkmax = INITHUNKMAX;  /* size of above arrays to begin with */
  62 static int      p_indent;       /* indent to patch */
  63 static off_t    p_base;         /* where to intuit this time */
  64 static LINENUM  p_bline;        /* line # of p_base */
  65 static off_t    p_start;        /* where intuit found a patch */
  66 static LINENUM  p_sline;        /* and the line number for it */
  67 static LINENUM  p_hunk_beg;     /* line number of current hunk */
  68 static LINENUM  p_efake = -1;   /* end of faked up lines--don't free */
  69 static LINENUM  p_bfake = -1;   /* beg of faked up lines */
  70 static FILE     *pfp = NULL;    /* patch file pointer */
  71 static char     *bestguess = NULL;      /* guess at correct filename */
  72
  73 static void     grow_hunkmax(void);
  74 static int      intuit_diff_type(void);
  75 static void     next_intuit_at(off_t, LINENUM);
  76 static void     skip_to(off_t, LINENUM);
  77 static size_t   pgets(bool _do_indent);
  78 static char     *best_name(const struct file_name *, bool);
  79 static char     *posix_name(const struct file_name *, bool);
  80 static size_t   num_components(const char *);
  81 static LINENUM  strtolinenum(char *, char **);
  82
  83 /*
  84  * Prepare to look for the next patch in the patch file.
  85  */
  86 void
  87 re_patch(void)
  88 {
  89         p_first = 0;
  90         p_newfirst = 0;
  91         p_ptrn_lines = 0;
  92         p_repl_lines = 0;
  93         p_end = (LINENUM) - 1;
  94         p_max = 0;
  95         p_indent = 0;
  96 }
  97
  98 /*
  99  * Open the patch file at the beginning of time.
 100  */
 101 void
 102 open_patch_file(const char *filename)
 103 {
 104         struct stat filestat;
 105         int nr, nw;
 106
 107         if (filename == NULL || *filename == '\0' || strEQ(filename, "-")) {
 108                 pfp = fopen(TMPPATNAME, "w");
 109                 if (pfp == NULL)
 110                         pfatal("can't create %s", TMPPATNAME);
 111                 while ((nr = fread(buf, 1, buf_size, stdin)) > 0) {
 112                         nw = fwrite(buf, 1, nr, pfp);
 113                         if (nr != nw)
 114                                 pfatal("write error to %s", TMPPATNAME);
 115                 }
 116                 if (ferror(pfp) || fclose(pfp))
 117                         pfatal("can't write %s", TMPPATNAME);
 118                 filename = TMPPATNAME;
 119         }
 120         pfp = fopen(filename, "r");
 121         if (pfp == NULL)
 122                 pfatal("patch file %s not found", filename);
 123         if (fstat(fileno(pfp), &filestat))
 124                 pfatal("can't stat %s", filename);
 125         p_filesize = filestat.st_size;
 126         next_intuit_at(0, 1L);  /* start at the beginning */
 127         set_hunkmax();
 128 }
 129
 130 /*
 131  * Make sure our dynamically realloced tables are malloced to begin with.
 132  */
 133 void
 134 set_hunkmax(void)
 135 {
 136         if (p_line == NULL)
 137                 p_line = malloc(hunkmax * sizeof(char *));
 138         if (p_len == NULL)
 139                 p_len = malloc(hunkmax * sizeof(unsigned short));
 140         if (p_char == NULL)
 141                 p_char = malloc(hunkmax * sizeof(char));
 142 }
 143
 144 /*
 145  * Enlarge the arrays containing the current hunk of patch.
 146  */
 147 static void
 148 grow_hunkmax(void)
 149 {
 150         int new_hunkmax = hunkmax * 2;
 151
 152         if (p_line == NULL || p_len == NULL || p_char == NULL)
 153                 fatal("Internal memory allocation error\n");
 154
 155         p_line = reallocf(p_line, new_hunkmax * sizeof(char *));
 156         p_len = reallocf(p_len, new_hunkmax * sizeof(unsigned short));
 157         p_char = reallocf(p_char, new_hunkmax * sizeof(char));
 158
 159         if (p_line != NULL && p_len != NULL && p_char != NULL) {
 160                 hunkmax = new_hunkmax;
 161                 return;
 162         }
 163
 164         if (!using_plan_a)
 165                 fatal("out of memory\n");
 166         out_of_mem = true;      /* whatever is null will be allocated again */
 167                                 /* from within plan_a(), of all places */
 168 }
 169
 170 /* True if the remainder of the patch file contains a diff of some sort. */
 171
 172 bool
 173 there_is_another_patch(void)
 174 {
 175         bool exists = false;
 176
 177         if (p_base != 0 && p_base >= p_filesize) {
 178                 if (verbose)
 179                         say("done\n");
 180                 return false;
 181         }
 182         if (p_filesize == 0)
 183                 return false;
 184         nonempty_patchf_seen = true;
 185         if (verbose)
 186                 say("Hmm...");
 187         diff_type = intuit_diff_type();
 188         if (!diff_type) {
 189                 if (p_base != 0) {
 190                         if (verbose)
 191                                 say("  Ignoring the trailing garbage.\ndone\n");
 192                 } else
 193                         say("  I can't seem to find a patch in there anywhere.\n");
 194                 return false;
 195         }
 196         if (verbose)
 197                 say("  %sooks like %s to me...\n",
 198                     (p_base == 0 ? "L" : "The next patch l"),
 199                     diff_type == UNI_DIFF ? "a unified diff" :
 200                     diff_type == CONTEXT_DIFF ? "a context diff" :
 201                 diff_type == NEW_CONTEXT_DIFF ? "a new-style context diff" :
 202                     diff_type == NORMAL_DIFF ? "a normal diff" :
 203                     "an ed script");
 204         if (p_indent && verbose)
 205                 say("(Patch is indented %d space%s.)\n", p_indent,
 206                     p_indent == 1 ? "" : "s");
 207         skip_to(p_start, p_sline);
 208         while (filearg[0] == NULL) {
 209                 if (force || batch) {
 210                         say("No file to patch.  Skipping...\n");
 211                         filearg[0] = xstrdup(bestguess);
 212                         skip_rest_of_patch = true;
 213                         return true;
 214                 }
 215                 ask("File to patch: ");
 216                 if (*buf != '\n') {
 217                         free(bestguess);
 218                         bestguess = xstrdup(buf);
 219                         filearg[0] = fetchname(buf, &exists, 0);
 220                 }
 221                 if (!exists) {
 222                         int def_skip = *bestguess == '\0';
 223                         ask("No file found--skip this patch? [%c] ",
 224                             def_skip  ? 'y' : 'n');
 225                         if (*buf == 'n' || (!def_skip && *buf != 'y'))
 226                                 continue;
 227                         if (verbose)
 228                                 say("Skipping patch...\n");
 229                         free(filearg[0]);
 230                         filearg[0] = fetchname(bestguess, &exists, 0);
 231                         skip_rest_of_patch = true;
 232                         return true;
 233                 }
 234         }
 235         return true;
 236 }
 237
 238 static void
 239 p4_fetchname(struct file_name *name, char *str)
 240 {
 241         char *t, *h;
 242
 243         /* Skip leading whitespace. */
 244         while (isspace((unsigned char)*str))
 245                 str++;
 246
 247         /* Remove the file revision number. */
 248         for (t = str, h = NULL; *t != '\0' && !isspace((unsigned char)*t); t++)
 249                 if (*t == '#')
 250                         h = t;
 251         if (h != NULL)
 252                 *h = '\0';
 253
 254         name->path = fetchname(str, &name->exists, strippath);
 255 }
 256
 257 /* Determine what kind of diff is in the remaining part of the patch file. */
 258
 259 static int
 260 intuit_diff_type(void)
 261 {
 262         off_t   this_line = 0, previous_line;
 263         off_t   first_command_line = -1;
 264         LINENUM fcl_line = -1;
 265         bool    last_line_was_command = false, this_is_a_command = false;
 266         bool    stars_last_line = false, stars_this_line = false;
 267         char    *s, *t;
 268         int     indent, retval;
 269         struct file_name names[MAX_FILE];
 270         int     piece_of_git = 0;
 271
 272         memset(names, 0, sizeof(names));
 273         ok_to_create_file = false;
 274         fseeko(pfp, p_base, SEEK_SET);
 275         p_input_line = p_bline - 1;
 276         for (;;) {
 277                 previous_line = this_line;
 278                 last_line_was_command = this_is_a_command;
 279                 stars_last_line = stars_this_line;
 280                 this_line = ftello(pfp);
 281                 indent = 0;
 282                 p_input_line++;
 283                 if (pgets(false) == 0) {
 284                         if (first_command_line >= 0) {
 285                                 /* nothing but deletes!? */
 286                                 p_start = first_command_line;
 287                                 p_sline = fcl_line;
 288                                 retval = ED_DIFF;
 289                                 goto scan_exit;
 290                         } else {
 291                                 p_start = this_line;
 292                                 p_sline = p_input_line;
 293                                 retval = 0;
 294                                 goto scan_exit;
 295                         }
 296                 }
 297                 for (s = buf; *s == ' ' || *s == '\t' || *s == 'X'; s++) {
 298                         if (*s == '\t')
 299                                 indent += 8 - (indent % 8);
 300                         else
 301                                 indent++;
 302                 }
 303                 for (t = s; isdigit((unsigned char)*t) || *t == ','; t++)
 304                         ;
 305                 this_is_a_command = (isdigit((unsigned char)*s) &&
 306                     (*t == 'd' || *t == 'c' || *t == 'a'));
 307                 if (first_command_line < 0 && this_is_a_command) {
 308                         first_command_line = this_line;
 309                         fcl_line = p_input_line;
 310                         p_indent = indent;      /* assume this for now */
 311                 }
 312                 if (!stars_last_line && strnEQ(s, "*** ", 4))
 313                         names[OLD_FILE].path = fetchname(s + 4,
 314                             &names[OLD_FILE].exists, strippath);
 315                 else if (strnEQ(s, "--- ", 4)) {
 316                         size_t off = 4;
 317                         if (piece_of_git && strippath == 957 &&
 318                             strnEQ(s, "--- a/", 6))
 319                                 off = 6;
 320                         names[NEW_FILE].path = fetchname(s + off,
 321                             &names[NEW_FILE].exists, strippath);
 322                 } else if (strnEQ(s, "+++ ", 4)) {
 323                         /* pretend it is the old name */
 324                         size_t off = 4;
 325                         if (piece_of_git && strippath == 957 &&
 326                             strnEQ(s, "+++ b/", 6))
 327                                 off = 6;
 328                         names[OLD_FILE].path = fetchname(s + off,
 329                             &names[OLD_FILE].exists, strippath);
 330                 } else if (strnEQ(s, "Index:", 6))
 331                         names[INDEX_FILE].path = fetchname(s + 6,
 332                             &names[INDEX_FILE].exists, strippath);
 333                 else if (strnEQ(s, "Prereq:", 7)) {
 334                         for (t = s + 7; isspace((unsigned char)*t); t++)
 335                                 ;
 336                         revision = xstrdup(t);
 337                         for (t = revision;
 338                              *t && !isspace((unsigned char)*t); t++)
 339                                 ;
 340                         *t = '\0';
 341                         if (*revision == '\0') {
 342                                 free(revision);
 343                                 revision = NULL;
 344                         }
 345                 } else if (strnEQ(s, "diff --git a/", 13)) {
 346                         /* Git-style diffs. */
 347                         piece_of_git = 1;
 348                 } else if (strnEQ(s, "==== ", 5)) {
 349                         /* Perforce-style diffs. */
 350                         if ((t = strstr(s + 5, " - ")) != NULL)
 351                                 p4_fetchname(&names[NEW_FILE], t + 3);
 352                         p4_fetchname(&names[OLD_FILE], s + 5);
 353                 }
 354                 if ((!diff_type || diff_type == ED_DIFF) &&
 355                     first_command_line >= 0 &&
 356                     strEQ(s, ".\n")) {
 357                         p_indent = indent;
 358                         p_start = first_command_line;
 359                         p_sline = fcl_line;
 360                         retval = ED_DIFF;
 361                         goto scan_exit;
 362                 }
 363                 if ((!diff_type || diff_type == UNI_DIFF) && strnEQ(s, "@@ -", 4)) {
 364                         if (strnEQ(s + 4, "0,0", 3))
 365                                 ok_to_create_file = true;
 366                         p_indent = indent;
 367                         p_start = this_line;
 368                         p_sline = p_input_line;
 369                         retval = UNI_DIFF;
 370                         goto scan_exit;
 371                 }
 372                 stars_this_line = strnEQ(s, "********", 8);
 373                 if ((!diff_type || diff_type == CONTEXT_DIFF) && stars_last_line &&
 374                     strnEQ(s, "*** ", 4)) {
 375                         if (strtolinenum(s + 4, &s) == 0)
 376                                 ok_to_create_file = true;
 377                         /*
 378                          * If this is a new context diff the character just
 379                          * at the end of the line is a '*'.
 380                          */
 381                         while (*s && *s != '\n')
 382                                 s++;
 383                         p_indent = indent;
 384                         p_start = previous_line;
 385                         p_sline = p_input_line - 1;
 386                         retval = (*(s - 1) == '*' ? NEW_CONTEXT_DIFF : CONTEXT_DIFF);
 387                         goto scan_exit;
 388                 }
 389                 if ((!diff_type || diff_type == NORMAL_DIFF) &&
 390                     last_line_was_command &&
 391                     (strnEQ(s, "< ", 2) || strnEQ(s, "> ", 2))) {
 392                         p_start = previous_line;
 393                         p_sline = p_input_line - 1;
 394                         p_indent = indent;
 395                         retval = NORMAL_DIFF;
 396                         goto scan_exit;
 397                 }
 398         }
 399 scan_exit:
 400         if (retval == UNI_DIFF) {
 401                 /* unswap old and new */
 402                 struct file_name tmp = names[OLD_FILE];
 403                 names[OLD_FILE] = names[NEW_FILE];
 404                 names[NEW_FILE] = tmp;
 405         }
 406         if (filearg[0] == NULL) {
 407                 if (posix)
 408                         filearg[0] = posix_name(names, ok_to_create_file);
 409                 else {
 410                         /* Ignore the Index: name for context diffs, like GNU */
 411                         if (names[OLD_FILE].path != NULL ||
 412                             names[NEW_FILE].path != NULL) {
 413                                 free(names[INDEX_FILE].path);
 414                                 names[INDEX_FILE].path = NULL;
 415                         }
 416                         filearg[0] = best_name(names, ok_to_create_file);
 417                 }
 418         }
 419
 420         free(bestguess);
 421         bestguess = NULL;
 422         if (filearg[0] != NULL)
 423                 bestguess = xstrdup(filearg[0]);
 424         else if (!ok_to_create_file) {
 425                 /*
 426                  * We don't want to create a new file but we need a
 427                  * filename to set bestguess.  Avoid setting filearg[0]
 428                  * so the file is not created automatically.
 429                  */
 430                 if (posix)
 431                         bestguess = posix_name(names, true);
 432                 else
 433                         bestguess = best_name(names, true);
 434         }
 435         free(names[OLD_FILE].path);
 436         free(names[NEW_FILE].path);
 437         free(names[INDEX_FILE].path);
 438         return retval;
 439 }
 440
 441 /*
 442  * Remember where this patch ends so we know where to start up again.
 443  */
 444 static void
 445 next_intuit_at(off_t file_pos, LINENUM file_line)
 446 {
 447         p_base = file_pos;
 448         p_bline = file_line;
 449 }
 450
 451 /*
 452  * Basically a verbose fseeko() to the actual diff listing.
 453  */
 454 static void
 455 skip_to(off_t file_pos, LINENUM file_line)
 456 {
 457         size_t  len;
 458
 459         if (p_base > file_pos)
 460                 fatal("Internal error: seek %lld>%lld\n",
 461                    (long long)p_base, (long long)file_pos);
 462         if (verbose && p_base < file_pos) {
 463                 fseeko(pfp, p_base, SEEK_SET);
 464                 say("The text leading up to this was:\n--------------------------\n");
 465                 while (ftello(pfp) < file_pos) {
 466                         len = pgets(false);
 467                         if (len == 0)
 468                                 fatal("Unexpected end of file\n");
 469                         say("|%s", buf);
 470                 }
 471                 say("--------------------------\n");
 472         } else
 473                 fseeko(pfp, file_pos, SEEK_SET);
 474         p_input_line = file_line - 1;
 475 }
 476
 477 /* Make this a function for better debugging.  */
 478 static void
 479 malformed(void)
 480 {
 481         fatal("malformed patch at line %ld: %s", p_input_line, buf);
 482         /* about as informative as "Syntax error" in C */
 483 }
 484
 485 /*
 486  * True if the line has been discarded (i.e. it is a line saying
 487  *  "\ No newline at end of file".)
 488  */
 489 static bool
 490 remove_special_line(void)
 491 {
 492         int     c;
 493
 494         c = fgetc(pfp);
 495         if (c == '\\') {
 496                 do {
 497                         c = fgetc(pfp);
 498                 } while (c != EOF && c != '\n');
 499
 500                 return true;
 501         }
 502         if (c != EOF)
 503                 fseeko(pfp, -1, SEEK_CUR);
 504
 505         return false;
 506 }
 507
 508 /*
 509  * True if there is more of the current diff listing to process.
 510  */
 511 bool
 512 another_hunk(void)
 513 {
 514         off_t   line_beginning;                 /* file pos of the current line */
 515         LINENUM repl_beginning;                 /* index of --- line */
 516         LINENUM fillcnt;                        /* #lines of missing ptrn or repl */
 517         LINENUM fillsrc;                        /* index of first line to copy */
 518         LINENUM filldst;                        /* index of first missing line */
 519         bool    ptrn_spaces_eaten;              /* ptrn was slightly malformed */
 520         bool    repl_could_be_missing;          /* no + or ! lines in this hunk */
 521         bool    repl_missing;                   /* we are now backtracking */
 522         off_t   repl_backtrack_position;        /* file pos of first repl line */
 523         LINENUM repl_patch_line;                /* input line number for same */
 524         LINENUM ptrn_copiable;                  /* # of copiable lines in ptrn */
 525         char    *s;
 526         size_t  len;
 527         int     context = 0;
 528
 529         while (p_end >= 0) {
 530                 if (p_end == p_efake)
 531                         p_end = p_bfake;        /* don't free twice */
 532                 else
 533                         free(p_line[p_end]);
 534                 p_end--;
 535         }
 536         p_efake = -1;
 537
 538         p_max = hunkmax;        /* gets reduced when --- found */
 539         if (diff_type == CONTEXT_DIFF || diff_type == NEW_CONTEXT_DIFF) {
 540                 line_beginning = ftello(pfp);
 541                 repl_beginning = 0;
 542                 fillcnt = 0;
 543                 fillsrc = 0;
 544                 filldst = 0;
 545                 ptrn_spaces_eaten = false;
 546                 repl_could_be_missing = true;
 547                 repl_missing = false;
 548                 repl_backtrack_position = 0;
 549                 repl_patch_line = 0;
 550                 ptrn_copiable = 0;
 551
 552                 len = pgets(true);
 553                 p_input_line++;
 554                 if (len == 0 || strnNE(buf, "********", 8)) {
 555                         next_intuit_at(line_beginning, p_input_line);
 556                         return false;
 557                 }
 558                 p_context = 100;
 559                 p_hunk_beg = p_input_line + 1;
 560                 while (p_end < p_max) {
 561                         line_beginning = ftello(pfp);
 562                         len = pgets(true);
 563                         p_input_line++;
 564                         if (len == 0) {
 565                                 if (p_max - p_end < 4) {
 566                                         /* assume blank lines got chopped */
 567                                         strlcpy(buf, "  \n", buf_size);
 568                                 } else {
 569                                         if (repl_beginning && repl_could_be_missing) {
 570                                                 repl_missing = true;
 571                                                 goto hunk_done;
 572                                         }
 573                                         fatal("unexpected end of file in patch\n");
 574                                 }
 575                         }
 576                         p_end++;
 577                         if (p_end >= hunkmax)
 578                                 fatal("Internal error: hunk larger than hunk "
 579                                     "buffer size");
 580                         p_char[p_end] = *buf;
 581                         p_line[p_end] = NULL;
 582                         switch (*buf) {
 583                         case '*':
 584                                 if (strnEQ(buf, "********", 8)) {
 585                                         if (repl_beginning && repl_could_be_missing) {
 586                                                 repl_missing = true;
 587                                                 goto hunk_done;
 588                                         } else
 589                                                 fatal("unexpected end of hunk "
 590                                                     "at line %ld\n",
 591                                                     p_input_line);
 592                                 }
 593                                 if (p_end != 0) {
 594                                         if (repl_beginning && repl_could_be_missing) {
 595                                                 repl_missing = true;
 596                                                 goto hunk_done;
 597                                         }
 598                                         fatal("unexpected *** at line %ld: %s",
 599                                             p_input_line, buf);
 600                                 }
 601                                 context = 0;
 602                                 p_line[p_end] = savestr(buf);
 603                                 if (out_of_mem) {
 604                                         p_end--;
 605                                         return false;
 606                                 }
 607                                 for (s = buf;
 608                                      *s && !isdigit((unsigned char)*s); s++)
 609                                         ;
 610                                 if (!*s)
 611                                         malformed();
 612                                 if (strnEQ(s, "0,0", 3))
 613                                         memmove(s, s + 2, strlen(s + 2) + 1);
 614                                 p_first = strtolinenum(s, &s);
 615                                 if (*s == ',') {
 616                                         for (;
 617                                              *s && !isdigit((unsigned char)*s); s++)
 618                                                 ;
 619                                         if (!*s)
 620                                                 malformed();
 621                                         p_ptrn_lines = strtolinenum(s, &s) - p_first + 1;
 622                                         if (p_ptrn_lines < 0)
 623                                                 malformed();
 624                                 } else if (p_first)
 625                                         p_ptrn_lines = 1;
 626                                 else {
 627                                         p_ptrn_lines = 0;
 628                                         p_first = 1;
 629                                 }
 630                                 if (p_first >= LINENUM_MAX - p_ptrn_lines ||
 631                                     p_ptrn_lines >= LINENUM_MAX - 6)
 632                                         malformed();
 633
 634                                 /* we need this much at least */
 635                                 p_max = p_ptrn_lines + 6;
 636                                 while (p_max >= hunkmax)
 637                                         grow_hunkmax();
 638                                 p_max = hunkmax;
 639                                 break;
 640                         case '-':
 641                                 if (buf[1] == '-') {
 642                                         if (repl_beginning ||
 643                                             (p_end != p_ptrn_lines + 1 +
 644                                             (p_char[p_end - 1] == '\n'))) {
 645                                                 if (p_end == 1) {
 646                                                         /*
 647                                                          * `old' lines were omitted;
 648                                                          * set up to fill them in
 649                                                          * from 'new' context lines.
 650                                                          */
 651                                                         p_end = p_ptrn_lines + 1;
 652                                                         fillsrc = p_end + 1;
 653                                                         filldst = 1;
 654                                                         fillcnt = p_ptrn_lines;
 655                                                 } else {
 656                                                         if (repl_beginning) {
 657                                                                 if (repl_could_be_missing) {
 658                                                                         repl_missing = true;
 659                                                                         goto hunk_done;
 660                                                                 }
 661                                                                 fatal("duplicate \"---\" at line %ld--check line numbers at line %ld\n",
 662                                                                     p_input_line, p_hunk_beg + repl_beginning);
 663                                                         } else {
 664                                                                 fatal("%s \"---\" at line %ld--check line numbers at line %ld\n",
 665                                                                     (p_end <= p_ptrn_lines
 666                                                                     ? "Premature"
 667                                                                     : "Overdue"),
 668                                                                     p_input_line, p_hunk_beg);
 669                                                         }
 670                                                 }
 671                                         }
 672                                         repl_beginning = p_end;
 673                                         repl_backtrack_position = ftello(pfp);
 674                                         repl_patch_line = p_input_line;
 675                                         p_line[p_end] = savestr(buf);
 676                                         if (out_of_mem) {
 677                                                 p_end--;
 678                                                 return false;
 679                                         }
 680                                         p_char[p_end] = '=';
 681                                         for (s = buf; *s && !isdigit((unsigned char)*s); s++)
 682                                                 ;
 683                                         if (!*s)
 684                                                 malformed();
 685                                         p_newfirst = strtolinenum(s, &s);
 686                                         if (*s == ',') {
 687                                                 for (; *s && !isdigit((unsigned char)*s); s++)
 688                                                         ;
 689                                                 if (!*s)
 690                                                         malformed();
 691                                                 p_repl_lines = strtolinenum(s, &s) -
 692                                                     p_newfirst + 1;
 693                                                 if (p_repl_lines < 0)
 694                                                         malformed();
 695                                         } else if (p_newfirst)
 696                                                 p_repl_lines = 1;
 697                                         else {
 698                                                 p_repl_lines = 0;
 699                                                 p_newfirst = 1;
 700                                         }
 701                                         if (p_newfirst >= LINENUM_MAX - p_repl_lines ||
 702                                             p_repl_lines >= LINENUM_MAX - p_end)
 703                                                 malformed();
 704                                         p_max = p_repl_lines + p_end;
 705                                         if (p_max > MAXHUNKSIZE)
 706                                                 fatal("hunk too large (%ld lines) at line %ld: %s",
 707                                                     p_max, p_input_line, buf);
 708                                         while (p_max >= hunkmax)
 709                                                 grow_hunkmax();
 710                                         if (p_repl_lines != ptrn_copiable &&
 711                                             (p_context != 0 || p_repl_lines != 1))
 712                                                 repl_could_be_missing = false;
 713                                         break;
 714                                 }
 715                                 goto change_line;
 716                         case '+':
 717                         case '!':
 718                                 repl_could_be_missing = false;
 719                 change_line:
 720                                 if (buf[1] == '\n' && canonicalize)
 721                                         strlcpy(buf + 1, " \n", buf_size - 1);
 722                                 if (!isspace((unsigned char)buf[1]) &&
 723                                     buf[1] != '>' && buf[1] != '<' &&
 724                                     repl_beginning && repl_could_be_missing) {
 725                                         repl_missing = true;
 726                                         goto hunk_done;
 727                                 }
 728                                 if (context >= 0) {
 729                                         if (context < p_context)
 730                                                 p_context = context;
 731                                         context = -1000;
 732                                 }
 733                                 p_line[p_end] = savestr(buf + 2);
 734                                 if (out_of_mem) {
 735                                         p_end--;
 736                                         return false;
 737                                 }
 738                                 if (p_end == p_ptrn_lines) {
 739                                         if (remove_special_line()) {
 740                                                 int     l;
 741
 742                                                 l = strlen(p_line[p_end]) - 1;
 743                                                 (p_line[p_end])[l] = 0;
 744                                         }
 745                                 }
 746                                 break;
 747                         case '\t':
 748                         case '\n':      /* assume the 2 spaces got eaten */
 749                                 if (repl_beginning && repl_could_be_missing &&
 750                                     (!ptrn_spaces_eaten ||
 751                                     diff_type == NEW_CONTEXT_DIFF)) {
 752                                         repl_missing = true;
 753                                         goto hunk_done;
 754                                 }
 755                                 p_line[p_end] = savestr(buf);
 756                                 if (out_of_mem) {
 757                                         p_end--;
 758                                         return false;
 759                                 }
 760                                 if (p_end != p_ptrn_lines + 1) {
 761                                         ptrn_spaces_eaten |= (repl_beginning != 0);
 762                                         context++;
 763                                         if (!repl_beginning)
 764                                                 ptrn_copiable++;
 765                                         p_char[p_end] = ' ';
 766                                 }
 767                                 break;
 768                         case ' ':
 769                                 if (!isspace((unsigned char)buf[1]) &&
 770                                     repl_beginning && repl_could_be_missing) {
 771                                         repl_missing = true;
 772                                         goto hunk_done;
 773                                 }
 774                                 context++;
 775                                 if (!repl_beginning)
 776                                         ptrn_copiable++;
 777                                 p_line[p_end] = savestr(buf + 2);
 778                                 if (out_of_mem) {
 779                                         p_end--;
 780                                         return false;
 781                                 }
 782                                 break;
 783                         default:
 784                                 if (repl_beginning && repl_could_be_missing) {
 785                                         repl_missing = true;
 786                                         goto hunk_done;
 787                                 }
 788                                 malformed();
 789                         }
 790                         /* set up p_len for strncmp() so we don't have to */
 791                         /* assume null termination */
 792                         if (p_line[p_end])
 793                                 p_len[p_end] = strlen(p_line[p_end]);
 794                         else
 795                                 p_len[p_end] = 0;
 796                 }
 797
 798 hunk_done:
 799                 if (p_end >= 0 && !repl_beginning)
 800                         fatal("no --- found in patch at line %ld\n", pch_hunk_beg());
 801
 802                 if (repl_missing) {
 803
 804                         /* reset state back to just after --- */
 805                         p_input_line = repl_patch_line;
 806                         for (p_end--; p_end > repl_beginning; p_end--)
 807                                 free(p_line[p_end]);
 808                         fseeko(pfp, repl_backtrack_position, SEEK_SET);
 809
 810                         /* redundant 'new' context lines were omitted - set */
 811                         /* up to fill them in from the old file context */
 812                         if (!p_context && p_repl_lines == 1) {
 813                                 p_repl_lines = 0;
 814                                 p_max--;
 815                         }
 816                         fillsrc = 1;
 817                         filldst = repl_beginning + 1;
 818                         fillcnt = p_repl_lines;
 819                         p_end = p_max;
 820                 } else if (!p_context && fillcnt == 1) {
 821                         /* the first hunk was a null hunk with no context */
 822                         /* and we were expecting one line -- fix it up. */
 823                         while (filldst < p_end) {
 824                                 p_line[filldst] = p_line[filldst + 1];
 825                                 p_char[filldst] = p_char[filldst + 1];
 826                                 p_len[filldst] = p_len[filldst + 1];
 827                                 filldst++;
 828                         }
 829 #if 0
 830                         repl_beginning--;       /* this doesn't need to be fixed */
 831 #endif
 832                         p_end--;
 833                         p_first++;      /* do append rather than insert */
 834                         fillcnt = 0;
 835                         p_ptrn_lines = 0;
 836                 }
 837                 if (diff_type == CONTEXT_DIFF &&
 838                     (fillcnt || (p_first > 1 && ptrn_copiable > 2 * p_context))) {
 839                         if (verbose)
 840                                 say("%s\n%s\n%s\n",
 841                                     "(Fascinating--this is really a new-style context diff but without",
 842                                     "the telltale extra asterisks on the *** line that usually indicate",
 843                                     "the new style...)");
 844                         diff_type = NEW_CONTEXT_DIFF;
 845                 }
 846                 /* if there were omitted context lines, fill them in now */
 847                 if (fillcnt) {
 848                         p_bfake = filldst;      /* remember where not to free() */
 849                         p_efake = filldst + fillcnt - 1;
 850                         while (fillcnt-- > 0) {
 851                                 while (fillsrc <= p_end && p_char[fillsrc] != ' ')
 852                                         fillsrc++;
 853                                 if (fillsrc > p_end)
 854                                         fatal("replacement text or line numbers mangled in hunk at line %ld\n",
 855                                             p_hunk_beg);
 856                                 p_line[filldst] = p_line[fillsrc];
 857                                 p_char[filldst] = p_char[fillsrc];
 858                                 p_len[filldst] = p_len[fillsrc];
 859                                 fillsrc++;
 860                                 filldst++;
 861                         }
 862                         while (fillsrc <= p_end && fillsrc != repl_beginning &&
 863                             p_char[fillsrc] != ' ')
 864                                 fillsrc++;
 865 #ifdef DEBUGGING
 866                         if (debug & 64)
 867                                 printf("fillsrc %ld, filldst %ld, rb %ld, e+1 %ld\n",
 868                                 fillsrc, filldst, repl_beginning, p_end + 1);
 869 #endif
 870                         if (fillsrc != p_end + 1 && fillsrc != repl_beginning)
 871                                 malformed();
 872                         if (filldst != p_end + 1 && filldst != repl_beginning)
 873                                 malformed();
 874                 }
 875                 if (p_line[p_end] != NULL) {
 876                         if (remove_special_line()) {
 877                                 p_len[p_end] -= 1;
 878                                 (p_line[p_end])[p_len[p_end]] = 0;
 879                         }
 880                 }
 881         } else if (diff_type == UNI_DIFF) {
 882                 LINENUM fillold;        /* index of old lines */
 883                 LINENUM fillnew;        /* index of new lines */
 884                 char    ch;
 885
 886                 line_beginning = ftello(pfp); /* file pos of the current line */
 887                 len = pgets(true);
 888                 p_input_line++;
 889                 if (len == 0 || strnNE(buf, "@@ -", 4)) {
 890                         next_intuit_at(line_beginning, p_input_line);
 891                         return false;
 892                 }
 893                 s = buf + 4;
 894                 if (!*s)
 895                         malformed();
 896                 p_first = strtolinenum(s, &s);
 897                 if (*s == ',') {
 898                         p_ptrn_lines = strtolinenum(s + 1, &s);
 899                 } else
 900                         p_ptrn_lines = 1;
 901                 if (*s == ' ')
 902                         s++;
 903                 if (*s != '+' || !*++s)
 904                         malformed();
 905                 p_newfirst = strtolinenum(s, &s);
 906                 if (*s == ',') {
 907                         p_repl_lines = strtolinenum(s + 1, &s);
 908                 } else
 909                         p_repl_lines = 1;
 910                 if (*s == ' ')
 911                         s++;
 912                 if (*s != '@')
 913                         malformed();
 914                 if (p_first >= LINENUM_MAX - p_ptrn_lines ||
 915                     p_newfirst > LINENUM_MAX - p_repl_lines ||
 916                     p_ptrn_lines >= LINENUM_MAX - p_repl_lines - 1)
 917                         malformed();
 918                 if (!p_ptrn_lines)
 919                         p_first++;      /* do append rather than insert */
 920                 p_max = p_ptrn_lines + p_repl_lines + 1;
 921                 while (p_max >= hunkmax)
 922                         grow_hunkmax();
 923                 fillold = 1;
 924                 fillnew = fillold + p_ptrn_lines;
 925                 p_end = fillnew + p_repl_lines;
 926                 snprintf(buf, buf_size, "*** %ld,%ld ****\n", p_first,
 927                     p_first + p_ptrn_lines - 1);
 928                 p_line[0] = savestr(buf);
 929                 if (out_of_mem) {
 930                         p_end = -1;
 931                         return false;
 932                 }
 933                 p_char[0] = '*';
 934                 snprintf(buf, buf_size, "--- %ld,%ld ----\n", p_newfirst,
 935                     p_newfirst + p_repl_lines - 1);
 936                 p_line[fillnew] = savestr(buf);
 937                 if (out_of_mem) {
 938                         p_end = 0;
 939                         return false;
 940                 }
 941                 p_char[fillnew++] = '=';
 942                 p_context = 100;
 943                 context = 0;
 944                 p_hunk_beg = p_input_line + 1;
 945                 while (fillold <= p_ptrn_lines || fillnew <= p_end) {
 946                         line_beginning = ftello(pfp);
 947                         len = pgets(true);
 948                         p_input_line++;
 949                         if (len == 0) {
 950                                 if (p_max - fillnew < 3) {
 951                                         /* assume blank lines got chopped */
 952                                         strlcpy(buf, " \n", buf_size);
 953                                 } else {
 954                                         fatal("unexpected end of file in patch\n");
 955                                 }
 956                         }
 957                         if (*buf == '\t' || *buf == '\n') {
 958                                 ch = ' ';       /* assume the space got eaten */
 959                                 s = savestr(buf);
 960                         } else {
 961                                 ch = *buf;
 962                                 s = savestr(buf + 1);
 963                         }
 964                         if (out_of_mem) {
 965                                 while (--fillnew > p_ptrn_lines)
 966                                         free(p_line[fillnew]);
 967                                 p_end = fillold - 1;
 968                                 return false;
 969                         }
 970                         switch (ch) {
 971                         case '-':
 972                                 if (fillold > p_ptrn_lines) {
 973                                         free(s);
 974                                         p_end = fillnew - 1;
 975                                         malformed();
 976                                 }
 977                                 p_char[fillold] = ch;
 978                                 p_line[fillold] = s;
 979                                 p_len[fillold++] = strlen(s);
 980                                 if (fillold > p_ptrn_lines) {
 981                                         if (remove_special_line()) {
 982                                                 p_len[fillold - 1] -= 1;
 983                                                 s[p_len[fillold - 1]] = 0;
 984                                         }
 985                                 }
 986                                 break;
 987                         case '=':
 988                                 ch = ' ';
 989                                 /* FALL THROUGH */
 990                         case ' ':
 991                                 if (fillold > p_ptrn_lines) {
 992                                         free(s);
 993                                         while (--fillnew > p_ptrn_lines)
 994                                                 free(p_line[fillnew]);
 995                                         p_end = fillold - 1;
 996                                         malformed();
 997                                 }
 998                                 context++;
 999                                 p_char[fillold] = ch;
1000                                 p_line[fillold] = s;
1001                                 p_len[fillold++] = strlen(s);
1002                                 s = savestr(s);
1003                                 if (out_of_mem) {
1004                                         while (--fillnew > p_ptrn_lines)
1005                                                 free(p_line[fillnew]);
1006                                         p_end = fillold - 1;
1007                                         return false;
1008                                 }
1009                                 if (fillold > p_ptrn_lines) {
1010                                         if (remove_special_line()) {
1011                                                 p_len[fillold - 1] -= 1;
1012                                                 s[p_len[fillold - 1]] = 0;
1013                                         }
1014                                 }
1015                                 /* FALL THROUGH */
1016                         case '+':
1017                                 if (fillnew > p_end) {
1018                                         free(s);
1019                                         while (--fillnew > p_ptrn_lines)
1020                                                 free(p_line[fillnew]);
1021                                         p_end = fillold - 1;
1022                                         malformed();
1023                                 }
1024                                 p_char[fillnew] = ch;
1025                                 p_line[fillnew] = s;
1026                                 p_len[fillnew++] = strlen(s);
1027                                 if (fillold > p_ptrn_lines) {
1028                                         if (remove_special_line()) {
1029                                                 p_len[fillnew - 1] -= 1;
1030                                                 s[p_len[fillnew - 1]] = 0;
1031                                         }
1032                                 }
1033                                 break;
1034                         default:
1035                                 p_end = fillnew;
1036                                 malformed();
1037                         }
1038                         if (ch != ' ' && context > 0) {
1039                                 if (context < p_context)
1040                                         p_context = context;
1041                                 context = -1000;
1042                         }
1043                 }               /* while */
1044         } else {                /* normal diff--fake it up */
1045                 char    hunk_type;
1046                 int     i;
1047                 LINENUM min, max;
1048
1049                 line_beginning = ftello(pfp);
1050                 p_context = 0;
1051                 len = pgets(true);
1052                 p_input_line++;
1053                 if (len == 0 || !isdigit((unsigned char)*buf)) {
1054                         next_intuit_at(line_beginning, p_input_line);
1055                         return false;
1056                 }
1057                 p_first = strtolinenum(buf, &s);
1058                 if (*s == ',') {
1059                         p_ptrn_lines = strtolinenum(s + 1, &s) - p_first + 1;
1060                         if (p_ptrn_lines < 0)
1061                                 malformed();
1062                 } else
1063                         p_ptrn_lines = (*s != 'a');
1064                 hunk_type = *s;
1065                 if (hunk_type == 'a')
1066                         p_first++;      /* do append rather than insert */
1067                 min = strtolinenum(s + 1, &s);
1068                 if (*s == ',')
1069                         max = strtolinenum(s + 1, &s);
1070                 else
1071                         max = min;
1072                 if (min < 0 || min > max || max - min == LINENUM_MAX)
1073                         malformed();
1074                 if (hunk_type == 'd')
1075                         min++;
1076                 p_newfirst = min;
1077                 p_repl_lines = max - min + 1;
1078                 if (p_newfirst > LINENUM_MAX - p_repl_lines ||
1079                     p_ptrn_lines >= LINENUM_MAX - p_repl_lines - 1)
1080                         malformed();
1081                 p_end = p_ptrn_lines + p_repl_lines + 1;
1082                 if (p_end > MAXHUNKSIZE)
1083                         fatal("hunk too large (%ld lines) at line %ld: %s",
1084                             p_end, p_input_line, buf);
1085                 while (p_end >= hunkmax)
1086                         grow_hunkmax();
1087                 snprintf(buf, buf_size, "*** %ld,%ld\n", p_first,
1088                     p_first + p_ptrn_lines - 1);
1089                 p_line[0] = savestr(buf);
1090                 if (out_of_mem) {
1091                         p_end = -1;
1092                         return false;
1093                 }
1094                 p_char[0] = '*';
1095                 for (i = 1; i <= p_ptrn_lines; i++) {
1096                         len = pgets(true);
1097                         p_input_line++;
1098                         if (len == 0)
1099                                 fatal("unexpected end of file in patch at line %ld\n",
1100                                     p_input_line);
1101                         if (*buf != '<')
1102                                 fatal("< expected at line %ld of patch\n",
1103                                     p_input_line);
1104                         p_line[i] = savestr(buf + 2);
1105                         if (out_of_mem) {
1106                                 p_end = i - 1;
1107                                 return false;
1108                         }
1109                         p_len[i] = strlen(p_line[i]);
1110                         p_char[i] = '-';
1111                 }
1112
1113                 if (remove_special_line()) {
1114                         p_len[i - 1] -= 1;
1115                         (p_line[i - 1])[p_len[i - 1]] = 0;
1116                 }
1117                 if (hunk_type == 'c') {
1118                         len = pgets(true);
1119                         p_input_line++;
1120                         if (len == 0)
1121                                 fatal("unexpected end of file in patch at line %ld\n",
1122                                     p_input_line);
1123                         if (*buf != '-')
1124                                 fatal("--- expected at line %ld of patch\n",
1125                                     p_input_line);
1126                 }
1127                 snprintf(buf, buf_size, "--- %ld,%ld\n", min, max);
1128                 p_line[i] = savestr(buf);
1129                 if (out_of_mem) {
1130                         p_end = i - 1;
1131                         return false;
1132                 }
1133                 p_char[i] = '=';
1134                 for (i++; i <= p_end; i++) {
1135                         len = pgets(true);
1136                         p_input_line++;
1137                         if (len == 0)
1138                                 fatal("unexpected end of file in patch at line %ld\n",
1139                                     p_input_line);
1140                         if (*buf != '>')
1141                                 fatal("> expected at line %ld of patch\n",
1142                                     p_input_line);
1143                         /* Don't overrun if we don't have enough line */
1144                         if (len > 2)
1145                                 p_line[i] = savestr(buf + 2);
1146                         else
1147                                 p_line[i] = savestr("");
1148
1149                         if (out_of_mem) {
1150                                 p_end = i - 1;
1151                                 return false;
1152                         }
1153                         p_len[i] = strlen(p_line[i]);
1154                         p_char[i] = '+';
1155                 }
1156
1157                 if (remove_special_line()) {
1158                         p_len[i - 1] -= 1;
1159                         (p_line[i - 1])[p_len[i - 1]] = 0;
1160                 }
1161         }
1162         if (reverse)            /* backwards patch? */
1163                 if (!pch_swap())
1164                         say("Not enough memory to swap next hunk!\n");
1165 #ifdef DEBUGGING
1166         if (debug & 2) {
1167                 LINENUM i;
1168                 char    special;
1169
1170                 for (i = 0; i <= p_end; i++) {
1171                         if (i == p_ptrn_lines)
1172                                 special = '^';
1173                         else
1174                                 special = ' ';
1175                         fprintf(stderr, "%3ld %c %c %s", i, p_char[i],
1176                             special, p_line[i]);
1177                         fflush(stderr);
1178                 }
1179         }
1180 #endif
1181         if (p_end + 1 < hunkmax)/* paranoia reigns supreme... */
1182                 p_char[p_end + 1] = '^';        /* add a stopper for apply_hunk */
1183         return true;
1184 }
1185
1186 /*
1187  * Input a line from the patch file.
1188  * Worry about indentation if do_indent is true.
1189  * The line is read directly into the buf global variable which
1190  * is resized if necessary in order to hold the complete line.
1191  * Returns the number of characters read including the terminating
1192  * '\n', if any.
1193  */
1194 size_t
1195 pgets(bool do_indent)
1196 {
1197         char *line;
1198         size_t len;
1199         int indent = 0, skipped = 0;
1200
1201         line = fgetln(pfp, &len);
1202         if (line != NULL) {
1203                 if (len + 1 > buf_size) {
1204                         while (len + 1 > buf_size)
1205                                 buf_size *= 2;
1206                         free(buf);
1207                         buf = malloc(buf_size);
1208                         if (buf == NULL)
1209                                 fatal("out of memory\n");
1210                 }
1211                 if (do_indent == 1 && p_indent) {
1212                         for (;
1213                             indent < p_indent && (*line == ' ' || *line == '\t' || *line == 'X');
1214                             line++, skipped++) {
1215                                 if (*line == '\t')
1216                                         indent += 8 - (indent %7);
1217                                 else
1218                                         indent++;
1219                         }
1220                 }
1221                 memcpy(buf, line, len - skipped);
1222                 buf[len - skipped] = '\0';
1223         }
1224         return len;
1225 }
1226
1227
1228 /*
1229  * Reverse the old and new portions of the current hunk.
1230  */
1231 bool
1232 pch_swap(void)
1233 {
1234         char    **tp_line;      /* the text of the hunk */
1235         unsigned short  *tp_len;/* length of each line */
1236         char    *tp_char;       /* +, -, and ! */
1237         LINENUM i;
1238         LINENUM n;
1239         bool    blankline = false;
1240         char    *s;
1241
1242         i = p_first;
1243         p_first = p_newfirst;
1244         p_newfirst = i;
1245
1246         /* make a scratch copy */
1247
1248         tp_line = p_line;
1249         tp_len = p_len;
1250         tp_char = p_char;
1251         p_line = NULL;  /* force set_hunkmax to allocate again */
1252         p_len = NULL;
1253         p_char = NULL;
1254         set_hunkmax();
1255         if (p_line == NULL || p_len == NULL || p_char == NULL) {
1256
1257                 free(p_line);
1258                 p_line = tp_line;
1259                 free(p_len);
1260                 p_len = tp_len;
1261                 free(p_char);
1262                 p_char = tp_char;
1263                 return false;   /* not enough memory to swap hunk! */
1264         }
1265         /* now turn the new into the old */
1266
1267         i = p_ptrn_lines + 1;
1268         if (tp_char[i] == '\n') {       /* account for possible blank line */
1269                 blankline = true;
1270                 i++;
1271         }
1272         if (p_efake >= 0) {     /* fix non-freeable ptr range */
1273                 if (p_efake <= i)
1274                         n = p_end - i + 1;
1275                 else
1276                         n = -i;
1277                 p_efake += n;
1278                 p_bfake += n;
1279         }
1280         for (n = 0; i <= p_end; i++, n++) {
1281                 p_line[n] = tp_line[i];
1282                 p_char[n] = tp_char[i];
1283                 if (p_char[n] == '+')
1284                         p_char[n] = '-';
1285                 p_len[n] = tp_len[i];
1286         }
1287         if (blankline) {
1288                 i = p_ptrn_lines + 1;
1289                 p_line[n] = tp_line[i];
1290                 p_char[n] = tp_char[i];
1291                 p_len[n] = tp_len[i];
1292                 n++;
1293         }
1294         if (p_char[0] != '=')
1295                 fatal("Malformed patch at line %ld: expected '=' found '%c'\n",
1296                     p_input_line, p_char[0]);
1297         p_char[0] = '*';
1298         for (s = p_line[0]; *s; s++)
1299                 if (*s == '-')
1300                         *s = '*';
1301
1302         /* now turn the old into the new */
1303
1304         if (p_char[0] != '*')
1305                 fatal("Malformed patch at line %ld: expected '*' found '%c'\n",
1306                     p_input_line, p_char[0]);
1307         tp_char[0] = '=';
1308         for (s = tp_line[0]; *s; s++)
1309                 if (*s == '*')
1310                         *s = '-';
1311         for (i = 0; n <= p_end; i++, n++) {
1312                 p_line[n] = tp_line[i];
1313                 p_char[n] = tp_char[i];
1314                 if (p_char[n] == '-')
1315                         p_char[n] = '+';
1316                 p_len[n] = tp_len[i];
1317         }
1318
1319         if (i != p_ptrn_lines + 1)
1320                 fatal("Malformed patch at line %ld: expected %ld lines, "
1321                     "got %ld\n",
1322                     p_input_line, p_ptrn_lines + 1, i);
1323
1324         i = p_ptrn_lines;
1325         p_ptrn_lines = p_repl_lines;
1326         p_repl_lines = i;
1327
1328         free(tp_line);
1329         free(tp_len);
1330         free(tp_char);
1331
1332         return true;
1333 }
1334
1335 /*
1336  * Return the specified line position in the old file of the old context.
1337  */
1338 LINENUM
1339 pch_first(void)
1340 {
1341         return p_first;
1342 }
1343
1344 /*
1345  * Return the number of lines of old context.
1346  */
1347 LINENUM
1348 pch_ptrn_lines(void)
1349 {
1350         return p_ptrn_lines;
1351 }
1352
1353 /*
1354  * Return the probable line position in the new file of the first line.
1355  */
1356 LINENUM
1357 pch_newfirst(void)
1358 {
1359         return p_newfirst;
1360 }
1361
1362 /*
1363  * Return the number of lines in the replacement text including context.
1364  */
1365 LINENUM
1366 pch_repl_lines(void)
1367 {
1368         return p_repl_lines;
1369 }
1370
1371 /*
1372  * Return the number of lines in the whole hunk.
1373  */
1374 LINENUM
1375 pch_end(void)
1376 {
1377         return p_end;
1378 }
1379
1380 /*
1381  * Return the number of context lines before the first changed line.
1382  */
1383 LINENUM
1384 pch_context(void)
1385 {
1386         return p_context;
1387 }
1388
1389 /*
1390  * Return the length of a particular patch line.
1391  */
1392 unsigned short
1393 pch_line_len(LINENUM line)
1394 {
1395         return p_len[line];
1396 }
1397
1398 /*
1399  * Return the control character (+, -, *, !, etc) for a patch line.
1400  */
1401 char
1402 pch_char(LINENUM line)
1403 {
1404         return p_char[line];
1405 }
1406
1407 /*
1408  * Return a pointer to a particular patch line.
1409  */
1410 char *
1411 pfetch(LINENUM line)
1412 {
1413         return p_line[line];
1414 }
1415
1416 /*
1417  * Return where in the patch file this hunk began, for error messages.
1418  */
1419 LINENUM
1420 pch_hunk_beg(void)
1421 {
1422         return p_hunk_beg;
1423 }
1424
1425 /*
1426  * Apply an ed script by feeding ed itself.
1427  */
1428 void
1429 do_ed_script(void)
1430 {
1431         char    *t;
1432         off_t   beginning_of_this_line;
1433         FILE    *pipefp = NULL;
1434         int     continuation;
1435
1436         if (!skip_rest_of_patch) {
1437                 if (copy_file(filearg[0], TMPOUTNAME) < 0) {
1438                         unlink(TMPOUTNAME);
1439                         fatal("can't create temp file %s", TMPOUTNAME);
1440                 }
1441                 snprintf(buf, buf_size, "%s%s%s", _PATH_RED,
1442                     verbose ? " " : " -s ", TMPOUTNAME);
1443                 pipefp = popen(buf, "w");
1444         }
1445         for (;;) {
1446                 beginning_of_this_line = ftello(pfp);
1447                 if (pgets(true) == 0) {
1448                         next_intuit_at(beginning_of_this_line, p_input_line);
1449                         break;
1450                 }
1451                 p_input_line++;
1452                 for (t = buf; isdigit((unsigned char)*t) || *t == ','; t++)
1453                         ;
1454                 /* POSIX defines allowed commands as {a,c,d,i,s} */
1455                 if (isdigit((unsigned char)*buf) &&
1456                     (*t == 'a' || *t == 'c' || *t == 'd' || *t == 'i' || *t == 's')) {
1457                         if (pipefp != NULL)
1458                                 fputs(buf, pipefp);
1459                         if (*t == 's') {
1460                                 for (;;) {
1461                                         continuation = 0;
1462                                         t = strchr(buf, '\0') - 1;
1463                                         while (--t >= buf && *t == '\\')
1464                                                 continuation = !continuation;
1465                                         if (!continuation ||
1466                                             pgets(true) == 0)
1467                                                 break;
1468                                         if (pipefp != NULL)
1469                                                 fputs(buf, pipefp);
1470                                 }
1471                         } else if (*t != 'd') {
1472                                 while (pgets(true)) {
1473                                         p_input_line++;
1474                                         if (pipefp != NULL)
1475                                                 fputs(buf, pipefp);
1476                                         if (strEQ(buf, ".\n"))
1477                                                 break;
1478                                 }
1479                         }
1480                 } else {
1481                         next_intuit_at(beginning_of_this_line, p_input_line);
1482                         break;
1483                 }
1484         }
1485         if (pipefp == NULL)
1486                 return;
1487         fprintf(pipefp, "w\n");
1488         fprintf(pipefp, "q\n");
1489         fflush(pipefp);
1490         pclose(pipefp);
1491         ignore_signals();
1492         if (!check_only) {
1493                 if (move_file(TMPOUTNAME, outname) < 0) {
1494                         toutkeep = true;
1495                         chmod(TMPOUTNAME, filemode);
1496                 } else
1497                         chmod(outname, filemode);
1498         }
1499         set_signals(1);
1500 }
1501
1502 /*
1503  * Choose the name of the file to be patched based on POSIX rules.
1504  * NOTE: the POSIX rules are amazingly stupid and we only follow them
1505  *       if the user specified --posix or set POSIXLY_CORRECT.
1506  */
1507 static char *
1508 posix_name(const struct file_name *names, bool assume_exists)
1509 {
1510         char *path = NULL;
1511         int i;
1512
1513         /*
1514          * POSIX states that the filename will be chosen from one
1515          * of the old, new and index names (in that order) if
1516          * the file exists relative to CWD after -p stripping.
1517          */
1518         for (i = 0; i < MAX_FILE; i++) {
1519                 if (names[i].path != NULL && names[i].exists) {
1520                         path = names[i].path;
1521                         break;
1522                 }
1523         }
1524         if (path == NULL && !assume_exists) {
1525                 /*
1526                  * No files found, check to see if the diff could be
1527                  * creating a new file.
1528                  */
1529                 if (path == NULL && ok_to_create_file &&
1530                     names[NEW_FILE].path != NULL)
1531                         path = names[NEW_FILE].path;
1532         }
1533
1534         return path ? xstrdup(path) : NULL;
1535 }
1536
1537 static char *
1538 compare_names(const struct file_name *names, bool assume_exists)
1539 {
1540         size_t min_components, min_baselen, min_len, tmp;
1541         char *best = NULL;
1542         char *path;
1543         int i;
1544
1545         /*
1546          * The "best" name is the one with the fewest number of path
1547          * components, the shortest basename length, and the shortest
1548          * overall length (in that order).  We only use the Index: file
1549          * if neither of the old or new files could be intuited from
1550          * the diff header.
1551          */
1552         min_components = min_baselen = min_len = SIZE_MAX;
1553         for (i = INDEX_FILE; i >= OLD_FILE; i--) {
1554                 path = names[i].path;
1555                 if (path == NULL || (!names[i].exists && !assume_exists))
1556                         continue;
1557                 if ((tmp = num_components(path)) > min_components)
1558                         continue;
1559                 if (tmp < min_components) {
1560                         min_components = tmp;
1561                         best = path;
1562                 }
1563                 if ((tmp = strlen(basename(path))) > min_baselen)
1564                         continue;
1565                 if (tmp < min_baselen) {
1566                         min_baselen = tmp;
1567                         best = path;
1568                 }
1569                 if ((tmp = strlen(path)) > min_len)
1570                         continue;
1571                 min_len = tmp;
1572                 best = path;
1573         }
1574         return best;
1575 }
1576
1577 /*
1578  * Choose the name of the file to be patched based the "best" one
1579  * available.
1580  */
1581 static char *
1582 best_name(const struct file_name *names, bool assume_exists)
1583 {
1584         char *best;
1585
1586         best = compare_names(names, assume_exists);
1587
1588         /* No match?  Check to see if the diff could be creating a new file. */
1589         if (best == NULL && ok_to_create_file)
1590                 best = names[NEW_FILE].path;
1591
1592         return best ? xstrdup(best) : NULL;
1593 }
1594
1595 static size_t
1596 num_components(const char *path)
1597 {
1598         size_t n;
1599         const char *cp;
1600
1601         for (n = 0, cp = path; (cp = strchr(cp, '/')) != NULL; n++, cp++) {
1602                 while (*cp == '/')
1603                         cp++;           /* skip consecutive slashes */
1604         }
1605         return n;
1606 }
1607
1608 /*
1609  * Convert number at NPTR into LINENUM and save address of first
1610  * character that is not a digit in ENDPTR.  If conversion is not
1611  * possible, call fatal.
1612  */
1613 static LINENUM
1614 strtolinenum(char *nptr, char **endptr)
1615 {
1616         LINENUM rv;
1617         char c;
1618         char *p;
1619         const char *errstr;
1620
1621         for (p = nptr; isdigit((unsigned char)*p); p++)
1622                 ;
1623
1624         if (p == nptr)
1625                 malformed();
1626
1627         c = *p;
1628         *p = '\0';
1629
1630         rv = strtonum(nptr, 0, LINENUM_MAX, &errstr);
1631         if (errstr != NULL)
1632                 fatal("invalid line number at line %ld: `%s' is %s\n",
1633                     p_input_line, nptr, errstr);
1634
1635         *p = c;
1636         *endptr = p;
1637
1638         return rv;
1639 }