editors/patch.c

   1 /* vi: set sw=4 ts=4:
   2  *
   3  * Apply a "universal" diff.
   4  * Adapted from toybox's patch implementation.
   5  *
   6  * Copyright 2007 Rob Landley <rob@landley.net>
   7  *
   8  * see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
   9  * (But only does -u, because who still cares about "ed"?)
  10  *
  11  * TODO:
  12  * -b backup
  13  * -l treat all whitespace as a single space
  14  * -d chdir first
  15  * -D define wrap #ifdef and #ifndef around changes
  16  * -o outfile output here instead of in place
  17  * -r rejectfile write rejected hunks to this file
  18  * --dry-run (regression!)
  19  *
  20  * -f force (no questions asked)
  21  * -F fuzz (number, default 2)
  22  * [file] which file to patch
  23  */
  24
  25 //config:config PATCH
  26 //config:       bool "patch"
  27 //config:       default y
  28 //config:       help
  29 //config:         Apply a unified diff formatted patch.
  30
  31 //applet:IF_PATCH(APPLET(patch, BB_DIR_USR_BIN, BB_SUID_DROP))
  32
  33 //kbuild:lib-$(CONFIG_PATCH) += patch.o
  34
  35 //usage:#define patch_trivial_usage
  36 //usage:       "[OPTIONS] [ORIGFILE [PATCHFILE]]"
  37 //usage:#define patch_full_usage "\n\n"
  38 //usage:        IF_LONG_OPTS(
  39 //usage:       "        -p,--strip N            Strip N leading components from file names"
  40 //usage:     "\n        -i,--input DIFF         Read DIFF instead of stdin"
  41 //usage:     "\n        -R,--reverse            Reverse patch"
  42 //usage:     "\n        -N,--forward            Ignore already applied patches"
  43 /*usage:     "\n        --dry-run               Don't actually change files" - TODO */
  44 //usage:     "\n        -E,--remove-empty-files Remove output files if they become empty"
  45 //usage:        )
  46 //usage:        IF_NOT_LONG_OPTS(
  47 //usage:       "        -p N    Strip N leading components from file names"
  48 //usage:     "\n        -i DIFF Read DIFF instead of stdin"
  49 //usage:     "\n        -R      Reverse patch"
  50 //usage:     "\n        -N      Ignore already applied patches"
  51 //usage:     "\n        -E      Remove output files if they become empty"
  52 //usage:        )
  53 /* -u "interpret as unified diff" is supported but not documented: this info is not useful for --help */
  54 /* -x "debug" is supported but does nothing */
  55 //usage:
  56 //usage:#define patch_example_usage
  57 //usage:       "$ patch -p1 < example.diff\n"
  58 //usage:       "$ patch -p0 -i example.diff"
  59
  60 #include "libbb.h"
  61
  62
  63 // libbb candidate?
  64
  65 struct double_list {
  66         struct double_list *next;
  67         struct double_list *prev;
  68         char *data;
  69 };
  70
  71 // Free all the elements of a linked list
  72 // Call freeit() on each element before freeing it.
  73 static void dlist_free(struct double_list *list, void (*freeit)(void *data))
  74 {
  75         while (list) {
  76                 void *pop = list;
  77                 list = list->next;
  78                 freeit(pop);
  79                 // Bail out also if list is circular.
  80                 if (list == pop) break;
  81         }
  82 }
  83
  84 // Add an entry before "list" element in (circular) doubly linked list
  85 static struct double_list *dlist_add(struct double_list **list, char *data)
  86 {
  87         struct double_list *llist;
  88         struct double_list *line = xmalloc(sizeof(*line));
  89
  90         line->data = data;
  91         llist = *list;
  92         if (llist) {
  93                 struct double_list *p;
  94                 line->next = llist;
  95                 p = line->prev = llist->prev;
  96                 // (list is circular, we assume p is never NULL)
  97                 p->next = line;
  98                 llist->prev = line;
  99         } else
 100                 *list = line->next = line->prev = line;
 101
 102         return line;
 103 }
 104
 105
 106 struct globals {
 107         char *infile;
 108         long prefix;
 109
 110         struct double_list *current_hunk;
 111
 112         long oldline, oldlen, newline, newlen;
 113         long linenum;
 114         int context, state, hunknum;
 115         int filein, fileout;
 116         char *tempname;
 117
 118         int exitval;
 119 };
 120 #define TT (*ptr_to_globals)
 121 #define INIT_TT() do { \
 122         SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
 123 } while (0)
 124
 125
 126 #define FLAG_STR "Rup:i:NEx"
 127 /* FLAG_REVERSE must be == 1! Code uses this fact. */
 128 #define FLAG_REVERSE (1 << 0)
 129 #define FLAG_u       (1 << 1)
 130 #define FLAG_PATHLEN (1 << 2)
 131 #define FLAG_INPUT   (1 << 3)
 132 #define FLAG_IGNORE  (1 << 4)
 133 #define FLAG_RMEMPTY (1 << 5)
 134 /* Enable this bit and use -x for debug output: */
 135 #define FLAG_DEBUG   (0 << 6)
 136
 137 // Dispose of a line of input, either by writing it out or discarding it.
 138
 139 // state < 2: just free
 140 // state = 2: write whole line to stderr
 141 // state = 3: write whole line to fileout
 142 // state > 3: write line+1 to fileout when *line != state
 143
 144 #define PATCH_DEBUG (option_mask32 & FLAG_DEBUG)
 145
 146 static void do_line(void *data)
 147 {
 148         struct double_list *dlist = data;
 149
 150         if (TT.state>1 && *dlist->data != TT.state)
 151                 fdprintf(TT.state == 2 ? 2 : TT.fileout,
 152                         "%s\n", dlist->data+(TT.state>3 ? 1 : 0));
 153
 154         if (PATCH_DEBUG) fdprintf(2, "DO %d: %s\n", TT.state, dlist->data);
 155
 156         free(dlist->data);
 157         free(dlist);
 158 }
 159
 160 static void finish_oldfile(void)
 161 {
 162         if (TT.tempname) {
 163                 // Copy the rest of the data and replace the original with the copy.
 164                 char *temp;
 165
 166                 if (TT.filein != -1) {
 167                         bb_copyfd_eof(TT.filein, TT.fileout);
 168                         xclose(TT.filein);
 169                 }
 170                 xclose(TT.fileout);
 171
 172                 temp = xstrdup(TT.tempname);
 173                 temp[strlen(temp) - 6] = '\0';
 174                 rename(TT.tempname, temp);
 175                 free(temp);
 176
 177                 free(TT.tempname);
 178                 TT.tempname = NULL;
 179         }
 180         TT.fileout = TT.filein = -1;
 181 }
 182
 183 static void fail_hunk(void)
 184 {
 185         if (!TT.current_hunk) return;
 186
 187         fdprintf(2, "Hunk %d FAILED %ld/%ld.\n", TT.hunknum, TT.oldline, TT.newline);
 188         TT.exitval = 1;
 189
 190         // If we got to this point, we've seeked to the end.  Discard changes to
 191         // this file and advance to next file.
 192
 193         TT.state = 2;
 194         TT.current_hunk->prev->next = NULL;
 195         dlist_free(TT.current_hunk, do_line);
 196         TT.current_hunk = NULL;
 197
 198         // Abort the copy and delete the temporary file.
 199         close(TT.filein);
 200         close(TT.fileout);
 201         unlink(TT.tempname);
 202         free(TT.tempname);
 203         TT.tempname = NULL;
 204
 205         TT.state = 0;
 206 }
 207
 208 // Given a hunk of a unified diff, make the appropriate change to the file.
 209 // This does not use the location information, but instead treats a hunk
 210 // as a sort of regex.  Copies data from input to output until it finds
 211 // the change to be made, then outputs the changed data and returns.
 212 // (Finding EOF first is an error.)  This is a single pass operation, so
 213 // multiple hunks must occur in order in the file.
 214
 215 static int apply_one_hunk(void)
 216 {
 217         struct double_list *plist, *buf = NULL, *check;
 218         int matcheof = 0, reverse = option_mask32 & FLAG_REVERSE, backwarn = 0;
 219         /* Do we try "dummy" revert to check whether
 220          * to silently skip this hunk? Used to implement -N.
 221          */
 222         int dummy_revert = 0;
 223
 224         // Break doubly linked list so we can use singly linked traversal function.
 225         TT.current_hunk->prev->next = NULL;
 226
 227         // Match EOF if there aren't as many ending context lines as beginning
 228         for (plist = TT.current_hunk; plist; plist = plist->next) {
 229                 if (plist->data[0]==' ') matcheof++;
 230                 else matcheof = 0;
 231                 if (PATCH_DEBUG) fdprintf(2, "HUNK:%s\n", plist->data);
 232         }
 233         matcheof = !matcheof || matcheof < TT.context;
 234
 235         if (PATCH_DEBUG) fdprintf(2,"MATCHEOF=%c\n", matcheof ? 'Y' : 'N');
 236
 237         // Loop through input data searching for this hunk.  Match all context
 238         // lines and all lines to be removed until we've found the end of a
 239         // complete hunk.
 240         plist = TT.current_hunk;
 241         buf = NULL;
 242         if (reverse ? TT.oldlen : TT.newlen) for (;;) {
 243                 char *data = xmalloc_reads(TT.filein, NULL);
 244
 245                 TT.linenum++;
 246
 247                 // Figure out which line of hunk to compare with next.  (Skip lines
 248                 // of the hunk we'd be adding.)
 249                 while (plist && *plist->data == "+-"[reverse]) {
 250                         if (data && !strcmp(data, plist->data+1)) {
 251                                 if (!backwarn) {
 252                                         backwarn = TT.linenum;
 253                                         if (option_mask32 & FLAG_IGNORE) {
 254                                                 dummy_revert = 1;
 255                                                 reverse ^= 1;
 256                                                 continue;
 257                                         }
 258                                 }
 259                         }
 260                         plist = plist->next;
 261                 }
 262
 263                 // Is this EOF?
 264                 if (!data) {
 265                         if (PATCH_DEBUG) fdprintf(2, "INEOF\n");
 266
 267                         // Does this hunk need to match EOF?
 268                         if (!plist && matcheof) break;
 269
 270                         if (backwarn)
 271                                 fdprintf(2,"Possibly reversed hunk %d at %ld\n",
 272                                         TT.hunknum, TT.linenum);
 273
 274                         // File ended before we found a place for this hunk.
 275                         fail_hunk();
 276                         goto done;
 277                 }
 278
 279                 if (PATCH_DEBUG) fdprintf(2, "IN: %s\n", data);
 280                 check = dlist_add(&buf, data);
 281
 282                 // Compare this line with next expected line of hunk.
 283                 // todo: teach the strcmp() to ignore whitespace.
 284
 285                 // A match can fail because the next line doesn't match, or because
 286                 // we hit the end of a hunk that needed EOF, and this isn't EOF.
 287
 288                 // If match failed, flush first line of buffered data and
 289                 // recheck buffered data for a new match until we find one or run
 290                 // out of buffer.
 291
 292                 for (;;) {
 293                         if (!plist || strcmp(check->data, plist->data+1)) {
 294                                 // Match failed.  Write out first line of buffered data and
 295                                 // recheck remaining buffered data for a new match.
 296
 297                                 if (PATCH_DEBUG)
 298                                         fdprintf(2, "NOT: %s\n", plist->data);
 299
 300                                 TT.state = 3;
 301                                 check = buf;
 302                                 buf = buf->next;
 303                                 check->prev->next = buf;
 304                                 buf->prev = check->prev;
 305                                 do_line(check);
 306                                 plist = TT.current_hunk;
 307
 308                                 // If we've reached the end of the buffer without confirming a
 309                                 // match, read more lines.
 310                                 if (check == buf) {
 311                                         buf = NULL;
 312                                         break;
 313                                 }
 314                                 check = buf;
 315                         } else {
 316                                 if (PATCH_DEBUG)
 317                                         fdprintf(2, "MAYBE: %s\n", plist->data);
 318                                 // This line matches.  Advance plist, detect successful match.
 319                                 plist = plist->next;
 320                                 if (!plist && !matcheof) goto out;
 321                                 check = check->next;
 322                                 if (check == buf) break;
 323                         }
 324                 }
 325         }
 326 out:
 327         // We have a match.  Emit changed data.
 328         TT.state = "-+"[reverse ^ dummy_revert];
 329         dlist_free(TT.current_hunk, do_line);
 330         TT.current_hunk = NULL;
 331         TT.state = 1;
 332 done:
 333         if (buf) {
 334                 buf->prev->next = NULL;
 335                 dlist_free(buf, do_line);
 336         }
 337
 338         return TT.state;
 339 }
 340
 341 // Read a patch file and find hunks, opening/creating/deleting files.
 342 // Call apply_one_hunk() on each hunk.
 343
 344 // state 0: Not in a hunk, look for +++.
 345 // state 1: Found +++ file indicator, look for @@
 346 // state 2: In hunk: counting initial context lines
 347 // state 3: In hunk: getting body
 348
 349 int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 350 int patch_main(int argc UNUSED_PARAM, char **argv)
 351 {
 352         int opts;
 353         int reverse, state = 0;
 354         char *oldname = NULL, *newname = NULL;
 355         char *opt_p, *opt_i;
 356         long oldlen = oldlen; /* for compiler */
 357         long newlen = newlen; /* for compiler */
 358
 359         INIT_TT();
 360
 361         opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
 362         argv += optind;
 363         reverse = opts & FLAG_REVERSE;
 364         TT.prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
 365         TT.filein = TT.fileout = -1;
 366         if (opts & FLAG_INPUT) {
 367                 xmove_fd(xopen_stdin(opt_i), STDIN_FILENO);
 368         } else {
 369                 if (argv[0] && argv[1]) {
 370                         xmove_fd(xopen_stdin(argv[1]), STDIN_FILENO);
 371                 }
 372         }
 373         if (argv[0]) {
 374                 oldname = xstrdup(argv[0]);
 375                 newname = xstrdup(argv[0]);
 376         }
 377
 378         // Loop through the lines in the patch
 379         for(;;) {
 380                 char *patchline;
 381
 382                 patchline = xmalloc_fgetline(stdin);
 383                 if (!patchline) break;
 384
 385                 // Other versions of patch accept damaged patches,
 386                 // so we need to also.
 387                 if (!*patchline) {
 388                         free(patchline);
 389                         patchline = xstrdup(" ");
 390                 }
 391
 392                 // Are we assembling a hunk?
 393                 if (state >= 2) {
 394                         if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
 395                                 dlist_add(&TT.current_hunk, patchline);
 396
 397                                 if (*patchline != '+') oldlen--;
 398                                 if (*patchline != '-') newlen--;
 399
 400                                 // Context line?
 401                                 if (*patchline==' ' && state==2) TT.context++;
 402                                 else state=3;
 403
 404                                 // If we've consumed all expected hunk lines, apply the hunk.
 405
 406                                 if (!oldlen && !newlen) state = apply_one_hunk();
 407                                 continue;
 408                         }
 409                         fail_hunk();
 410                         state = 0;
 411                         continue;
 412                 }
 413
 414                 // Open a new file?
 415                 if (!strncmp("--- ", patchline, 4) || !strncmp("+++ ", patchline, 4)) {
 416                         char *s, **name = reverse ? &newname : &oldname;
 417                         int i;
 418
 419                         if (*patchline == '+') {
 420                                 name = reverse ? &oldname : &newname;
 421                                 state = 1;
 422                         }
 423
 424                         finish_oldfile();
 425
 426                         if (!argv[0]) {
 427                                 free(*name);
 428                                 // Trim date from end of filename (if any).  We don't care.
 429                                 for (s = patchline+4; *s && *s!='\t'; s++)
 430                                         if (*s=='\\' && s[1]) s++;
 431                                 i = atoi(s);
 432                                 if (i>1900 && i<=1970)
 433                                         *name = xstrdup("/dev/null");
 434                                 else {
 435                                         *s = 0;
 436                                         *name = xstrdup(patchline+4);
 437                                 }
 438                         }
 439
 440                         // We defer actually opening the file because svn produces broken
 441                         // patches that don't signal they want to create a new file the
 442                         // way the patch man page says, so you have to read the first hunk
 443                         // and _guess_.
 444
 445                 // Start a new hunk?  Usually @@ -oldline,oldlen +newline,newlen @@
 446                 // but a missing ,value means the value is 1.
 447                 } else if (state == 1 && !strncmp("@@ -", patchline, 4)) {
 448                         int i;
 449                         char *s = patchline+4;
 450
 451                         // Read oldline[,oldlen] +newline[,newlen]
 452
 453                         TT.oldlen = oldlen = TT.newlen = newlen = 1;
 454                         TT.oldline = strtol(s, &s, 10);
 455                         if (*s == ',') TT.oldlen = oldlen = strtol(s+1, &s, 10);
 456                         TT.newline = strtol(s+2, &s, 10);
 457                         if (*s == ',') TT.newlen = newlen = strtol(s+1, &s, 10);
 458
 459                         if (oldlen < 1 && newlen < 1)
 460                                 bb_error_msg_and_die("Really? %s", patchline);
 461
 462                         TT.context = 0;
 463                         state = 2;
 464
 465                         // If this is the first hunk, open the file.
 466                         if (TT.filein == -1) {
 467                                 int oldsum, newsum, empty = 0;
 468                                 char *name;
 469
 470                                 oldsum = TT.oldline + oldlen;
 471                                 newsum = TT.newline + newlen;
 472
 473                                 name = reverse ? oldname : newname;
 474
 475                                 // We're deleting oldname if new file is /dev/null (before -p)
 476                                 // or if new hunk is empty (zero context) after patching
 477                                 if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum)) {
 478                                         name = reverse ? newname : oldname;
 479                                         empty++;
 480                                 }
 481
 482                                 // handle -p path truncation.
 483                                 for (i = 0, s = name; *s;) {
 484                                         if ((option_mask32 & FLAG_PATHLEN) && TT.prefix == i)
 485                                                 break;
 486                                         if (*s++ != '/')
 487                                                 continue;
 488                                         while (*s == '/')
 489                                                 s++;
 490                                         i++;
 491                                         name = s;
 492                                 }
 493
 494                                 if (empty) {
 495                                         // File is empty after the patches have been applied
 496                                         state = 0;
 497                                         if (option_mask32 & FLAG_RMEMPTY) {
 498                                                 // If flag -E or --remove-empty-files is set
 499                                                 printf("removing %s\n", name);
 500                                                 xunlink(name);
 501                                         } else {
 502                                                 printf("patching file %s\n", name);
 503                                                 xclose(xopen(name, O_WRONLY | O_TRUNC));
 504                                         }
 505                                 // If we've got a file to open, do so.
 506                                 } else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
 507                                         struct stat statbuf;
 508
 509                                         // If the old file was null, we're creating a new one.
 510                                         if (!strcmp(oldname, "/dev/null") || !oldsum) {
 511                                                 printf("creating %s\n", name);
 512                                                 s = strrchr(name, '/');
 513                                                 if (s) {
 514                                                         *s = 0;
 515                                                         bb_make_directory(name, -1, FILEUTILS_RECUR);
 516                                                         *s = '/';
 517                                                 }
 518                                                 TT.filein = xopen(name, O_CREAT|O_EXCL|O_RDWR);
 519                                         } else {
 520                                                 printf("patching file %s\n", name);
 521                                                 TT.filein = xopen(name, O_RDONLY);
 522                                         }
 523
 524                                         TT.tempname = xasprintf("%sXXXXXX", name);
 525                                         TT.fileout = xmkstemp(TT.tempname);
 526                                         // Set permissions of output file
 527                                         fstat(TT.filein, &statbuf);
 528                                         fchmod(TT.fileout, statbuf.st_mode);
 529
 530                                         TT.linenum = 0;
 531                                         TT.hunknum = 0;
 532                                 }
 533                         }
 534
 535                         TT.hunknum++;
 536
 537                         continue;
 538                 }
 539
 540                 // If we didn't continue above, discard this line.
 541                 free(patchline);
 542         }
 543
 544         finish_oldfile();
 545
 546         if (ENABLE_FEATURE_CLEAN_UP) {
 547                 free(oldname);
 548                 free(newname);
 549         }
 550
 551         return TT.exitval;
 552 }