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