summaryrefslogtreecommitdiff
path: root/editors/patch.c
blob: ea1fc097497dbab39a19b78b3797f706bf00ce98 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
/* vi: set sw=4 ts=4:
 *
 * Apply a "universal" diff.
 * Adapted from toybox's patch implementation.
 *
 * Copyright 2007 Rob Landley <rob@landley.net>
 *
 * see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
 * (But only does -u, because who still cares about "ed"?)
 *
 * TODO:
 * -b backup
 * -l treat all whitespace as a single space
 * -d chdir first
 * -D define wrap #ifdef and #ifndef around changes
 * -o outfile output here instead of in place
 * -r rejectfile write rejected hunks to this file
 * --dry-run (regression!)
 *
 * -f force (no questions asked)
 * -F fuzz (number, default 2)
 * [file] which file to patch
 */

//config:config PATCH
//config:	bool "patch"
//config:	default y
//config:	help
//config:	  Apply a unified diff formatted patch.

//applet:IF_PATCH(APPLET(patch, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_PATCH) += patch.o

//usage:#define patch_trivial_usage
//usage:       "[OPTIONS] [ORIGFILE [PATCHFILE]]"
//usage:#define patch_full_usage "\n\n"
//usage:	IF_LONG_OPTS(
//usage:       "	-p,--strip N		Strip N leading components from file names"
//usage:     "\n	-i,--input DIFF		Read DIFF instead of stdin"
//usage:     "\n	-R,--reverse		Reverse patch"
//usage:     "\n	-N,--forward		Ignore already applied patches"
/*usage:     "\n	--dry-run		Don't actually change files" - TODO */
//usage:     "\n	-E,--remove-empty-files	Remove output files if they become empty"
//usage:	)
//usage:	IF_NOT_LONG_OPTS(
//usage:       "	-p N	Strip N leading components from file names"
//usage:     "\n	-i DIFF	Read DIFF instead of stdin"
//usage:     "\n	-R	Reverse patch"
//usage:     "\n	-N	Ignore already applied patches"
//usage:     "\n	-E	Remove output files if they become empty"
//usage:	)
/* -u "interpret as unified diff" is supported but not documented: this info is not useful for --help */
/* -x "debug" is supported but does nothing */
//usage:
//usage:#define patch_example_usage
//usage:       "$ patch -p1 < example.diff\n"
//usage:       "$ patch -p0 -i example.diff"

#include "libbb.h"


// libbb candidate?

struct double_list {
	struct double_list *next;
	struct double_list *prev;
	char *data;
};

// Free all the elements of a linked list
// Call freeit() on each element before freeing it.
static void dlist_free(struct double_list *list, void (*freeit)(void *data))
{
	while (list) {
		void *pop = list;
		list = list->next;
		freeit(pop);
		// Bail out also if list is circular.
		if (list == pop) break;
	}
}

// Add an entry before "list" element in (circular) doubly linked list
static struct double_list *dlist_add(struct double_list **list, char *data)
{
	struct double_list *llist;
	struct double_list *line = xmalloc(sizeof(*line));

	line->data = data;
	llist = *list;
	if (llist) {
		struct double_list *p;
		line->next = llist;
		p = line->prev = llist->prev;
		// (list is circular, we assume p is never NULL)
		p->next = line;
		llist->prev = line;
	} else
		*list = line->next = line->prev = line;

	return line;
}


struct globals {
	char *infile;
	long prefix;

	struct double_list *current_hunk;

	long oldline, oldlen, newline, newlen;
	long linenum;
	int context, state, hunknum;
	int filein, fileout;
	char *tempname;

	int exitval;
};
#define TT (*ptr_to_globals)
#define INIT_TT() do { \
	SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
} while (0)


#define FLAG_STR "Rup:i:NEx"
/* FLAG_REVERSE must be == 1! Code uses this fact. */
#define FLAG_REVERSE (1 << 0)
#define FLAG_u       (1 << 1)
#define FLAG_PATHLEN (1 << 2)
#define FLAG_INPUT   (1 << 3)
#define FLAG_IGNORE  (1 << 4)
#define FLAG_RMEMPTY (1 << 5)
/* Enable this bit and use -x for debug output: */
#define FLAG_DEBUG   (0 << 6)

// Dispose of a line of input, either by writing it out or discarding it.

// state < 2: just free
// state = 2: write whole line to stderr
// state = 3: write whole line to fileout
// state > 3: write line+1 to fileout when *line != state

#define PATCH_DEBUG (option_mask32 & FLAG_DEBUG)

static void do_line(void *data)
{
	struct double_list *dlist = data;

	if (TT.state>1 && *dlist->data != TT.state)
		fdprintf(TT.state == 2 ? 2 : TT.fileout,
			"%s\n", dlist->data+(TT.state>3 ? 1 : 0));

	if (PATCH_DEBUG) fdprintf(2, "DO %d: %s\n", TT.state, dlist->data);

	free(dlist->data);
	free(dlist);
}

static void finish_oldfile(void)
{
	if (TT.tempname) {
		// Copy the rest of the data and replace the original with the copy.
		char *temp;

		if (TT.filein != -1) {
			bb_copyfd_eof(TT.filein, TT.fileout);
			xclose(TT.filein);
		}
		xclose(TT.fileout);

		temp = xstrdup(TT.tempname);
		temp[strlen(temp) - 6] = '\0';
		rename(TT.tempname, temp);
		free(temp);

		free(TT.tempname);
		TT.tempname = NULL;
	}
	TT.fileout = TT.filein = -1;
}

static void fail_hunk(void)
{
	if (!TT.current_hunk) return;

	fdprintf(2, "Hunk %d FAILED %ld/%ld.\n", TT.hunknum, TT.oldline, TT.newline);
	TT.exitval = 1;

	// If we got to this point, we've seeked to the end.  Discard changes to
	// this file and advance to next file.

	TT.state = 2;
	TT.current_hunk->prev->next = NULL;
	dlist_free(TT.current_hunk, do_line);
	TT.current_hunk = NULL;

	// Abort the copy and delete the temporary file.
	close(TT.filein);
	close(TT.fileout);
	unlink(TT.tempname);
	free(TT.tempname);
	TT.tempname = NULL;

	TT.state = 0;
}

// Given a hunk of a unified diff, make the appropriate change to the file.
// This does not use the location information, but instead treats a hunk
// as a sort of regex.  Copies data from input to output until it finds
// the change to be made, then outputs the changed data and returns.
// (Finding EOF first is an error.)  This is a single pass operation, so
// multiple hunks must occur in order in the file.

static int apply_one_hunk(void)
{
	struct double_list *plist, *buf = NULL, *check;
	int matcheof = 0, reverse = option_mask32 & FLAG_REVERSE, backwarn = 0;
	/* Do we try "dummy" revert to check whether
	 * to silently skip this hunk? Used to implement -N.
	 */
	int dummy_revert = 0;

	// Break doubly linked list so we can use singly linked traversal function.
	TT.current_hunk->prev->next = NULL;

	// Match EOF if there aren't as many ending context lines as beginning
	for (plist = TT.current_hunk; plist; plist = plist->next) {
		if (plist->data[0]==' ') matcheof++;
		else matcheof = 0;
		if (PATCH_DEBUG) fdprintf(2, "HUNK:%s\n", plist->data);
	}
	matcheof = !matcheof || matcheof < TT.context;

	if (PATCH_DEBUG) fdprintf(2,"MATCHEOF=%c\n", matcheof ? 'Y' : 'N');

	// Loop through input data searching for this hunk.  Match all context
	// lines and all lines to be removed until we've found the end of a
	// complete hunk.
	plist = TT.current_hunk;
	buf = NULL;
	if (reverse ? TT.oldlen : TT.newlen) for (;;) {
		char *data = xmalloc_reads(TT.filein, NULL);

		TT.linenum++;

		// Figure out which line of hunk to compare with next.  (Skip lines
		// of the hunk we'd be adding.)
		while (plist && *plist->data == "+-"[reverse]) {
			if (data && !strcmp(data, plist->data+1)) {
				if (!backwarn) {
					backwarn = TT.linenum;
					if (option_mask32 & FLAG_IGNORE) {
						dummy_revert = 1;
						reverse ^= 1;
						continue;
					}
				}
			}
			plist = plist->next;
		}

		// Is this EOF?
		if (!data) {
			if (PATCH_DEBUG) fdprintf(2, "INEOF\n");

			// Does this hunk need to match EOF?
			if (!plist && matcheof) break;

			if (backwarn)
				fdprintf(2,"Possibly reversed hunk %d at %ld\n",
					TT.hunknum, TT.linenum);

			// File ended before we found a place for this hunk.
			fail_hunk();
			goto done;
		}

		if (PATCH_DEBUG) fdprintf(2, "IN: %s\n", data);
		check = dlist_add(&buf, data);

		// Compare this line with next expected line of hunk.
		// todo: teach the strcmp() to ignore whitespace.

		// A match can fail because the next line doesn't match, or because
		// we hit the end of a hunk that needed EOF, and this isn't EOF.

		// If match failed, flush first line of buffered data and
		// recheck buffered data for a new match until we find one or run
		// out of buffer.

		for (;;) {
			while (plist && *plist->data == "+-"[reverse]) {
				if (!strcmp(check->data, plist->data+1) &&
				    !backwarn) {
					backwarn = TT.linenum;
					if (option_mask32 & FLAG_IGNORE) {
						dummy_revert = 1;
						reverse ^= 1;
					}
				}
				plist = plist->next;
			}
			if (!plist || strcmp(check->data, plist->data+1)) {
				// Match failed.  Write out first line of buffered data and
				// recheck remaining buffered data for a new match.

				if (PATCH_DEBUG)
					fdprintf(2, "NOT: %s\n", plist ? plist->data : "EOF");

				TT.state = 3;
				check = buf;
				buf = buf->next;
				check->prev->next = buf;
				buf->prev = check->prev;
				do_line(check);
				plist = TT.current_hunk;

				// If we've reached the end of the buffer without confirming a
				// match, read more lines.
				if (check == buf) {
					buf = NULL;
					break;
				}
				check = buf;
			} else {
				if (PATCH_DEBUG)
					fdprintf(2, "MAYBE: %s\n", plist->data);
				// This line matches.  Advance plist, detect successful match.
				plist = plist->next;
				if (!plist && !matcheof) goto out;
				check = check->next;
				if (check == buf) break;
			}
		}
	}
out:
	// We have a match.  Emit changed data.
	TT.state = "-+"[reverse ^ dummy_revert];
	dlist_free(TT.current_hunk, do_line);
	TT.current_hunk = NULL;
	TT.state = 1;
done:
	if (buf) {
		buf->prev->next = NULL;
		dlist_free(buf, do_line);
	}

	return TT.state;
}

// Read a patch file and find hunks, opening/creating/deleting files.
// Call apply_one_hunk() on each hunk.

// state 0: Not in a hunk, look for +++.
// state 1: Found +++ file indicator, look for @@
// state 2: In hunk: counting initial context lines
// state 3: In hunk: getting body
// Like GNU patch, we don't require a --- line before the +++, and
// also allow the --- after the +++ line.

int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int patch_main(int argc UNUSED_PARAM, char **argv)
{
	int opts;
	int reverse, state = 0;
	char *oldname = NULL, *newname = NULL;
	char *opt_p, *opt_i;
	long oldlen = oldlen; /* for compiler */
	long newlen = newlen; /* for compiler */

	INIT_TT();

	opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
	argv += optind;
	reverse = opts & FLAG_REVERSE;
	TT.prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
	TT.filein = TT.fileout = -1;
	if (opts & FLAG_INPUT) {
		xmove_fd(xopen_stdin(opt_i), STDIN_FILENO);
	} else {
		if (argv[0] && argv[1]) {
			xmove_fd(xopen_stdin(argv[1]), STDIN_FILENO);
		}
	}

	// Loop through the lines in the patch
	for(;;) {
		char *patchline;

		patchline = xmalloc_fgetline(stdin);
		if (!patchline) break;

		// Other versions of patch accept damaged patches,
		// so we need to also.
		if (!*patchline) {
			free(patchline);
			patchline = xstrdup(" ");
		}

		// Are we assembling a hunk?
		if (state >= 2) {
			if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
				dlist_add(&TT.current_hunk, patchline);

				if (*patchline != '+') oldlen--;
				if (*patchline != '-') newlen--;

				// Context line?
				if (*patchline==' ' && state==2) TT.context++;
				else state=3;

				// If we've consumed all expected hunk lines, apply the hunk.

				if (!oldlen && !newlen) state = apply_one_hunk();
				continue;
			}
			fail_hunk();
			state = 0;
			continue;
		}

		// Open a new file?
		if (is_prefixed_with(patchline, "--- ") || is_prefixed_with(patchline, "+++ ")) {
			char *s, **name = reverse ? &newname : &oldname;
			int i;

			if (*patchline == '+') {
				name = reverse ? &oldname : &newname;
				state = 1;
			}

			finish_oldfile();

			if (!argv[0]) {
				free(*name);
				// Trim date from end of filename (if any).  We don't care.
				for (s = patchline+4; *s && *s!='\t'; s++)
					if (*s=='\\' && s[1]) s++;
				i = atoi(s);
				if (i>1900 && i<=1970)
					*name = xstrdup("/dev/null");
				else {
					*s = 0;
					*name = xstrdup(patchline+4);
				}
			}

			// We defer actually opening the file because svn produces broken
			// patches that don't signal they want to create a new file the
			// way the patch man page says, so you have to read the first hunk
			// and _guess_.

		// Start a new hunk?  Usually @@ -oldline,oldlen +newline,newlen @@
		// but a missing ,value means the value is 1.
		} else if (state == 1 && is_prefixed_with(patchline, "@@ -")) {
			int i;
			char *s = patchline+4;

			// Read oldline[,oldlen] +newline[,newlen]

			TT.oldlen = oldlen = TT.newlen = newlen = 1;
			TT.oldline = strtol(s, &s, 10);
			if (*s == ',') TT.oldlen = oldlen = strtol(s+1, &s, 10);
			TT.newline = strtol(s+2, &s, 10);
			if (*s == ',') TT.newlen = newlen = strtol(s+1, &s, 10);

			if (oldlen < 1 && newlen < 1)
				bb_error_msg_and_die("Really? %s", patchline);

			TT.context = 0;
			state = 2;

			// If the --- line is missing or malformed, either oldname
			// or (for -R) newname could be NULL -- but not both.  Like
			// GNU patch, proceed based on the +++ line, and avoid SEGVs.
			if (!oldname)
				oldname = xstrdup("MISSING_FILENAME");
			if (!newname)
				newname = xstrdup("MISSING_FILENAME");

			// If this is the first hunk, open the file.
			if (TT.filein == -1) {
				int oldsum, newsum, empty = 0;
				char *name;

				oldsum = TT.oldline + oldlen;
				newsum = TT.newline + newlen;

				name = reverse ? oldname : newname;

				// We're deleting oldname if new file is /dev/null (before -p)
				// or if new hunk is empty (zero context) after patching
				if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum)) {
					name = reverse ? newname : oldname;
					empty = 1;
				}

				// Handle -p path truncation.
				for (i = 0, s = name; *s;) {
					if ((option_mask32 & FLAG_PATHLEN) && TT.prefix == i)
						break;
					if (*s++ != '/')
						continue;
					while (*s == '/')
						s++;
					i++;
					name = s;
				}
				// If "patch FILE_TO_PATCH", completely ignore name from patch
				if (argv[0])
					name = argv[0];

				if (empty) {
					// File is empty after the patches have been applied
					state = 0;
					if (option_mask32 & FLAG_RMEMPTY) {
						// If flag -E or --remove-empty-files is set
						printf("removing %s\n", name);
						xunlink(name);
					} else {
						printf("patching file %s\n", name);
						xclose(xopen(name, O_WRONLY | O_TRUNC));
					}
				// If we've got a file to open, do so.
				} else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
					struct stat statbuf;

					// If the old file was null, we're creating a new one.
					if (!strcmp(oldname, "/dev/null") || !oldsum) {
						printf("creating %s\n", name);
						s = strrchr(name, '/');
						if (s) {
							*s = 0;
							bb_make_directory(name, -1, FILEUTILS_RECUR);
							*s = '/';
						}
						TT.filein = xopen(name, O_CREAT|O_EXCL|O_RDWR);
					} else {
						printf("patching file %s\n", name);
						TT.filein = xopen(name, O_RDONLY);
					}

					TT.tempname = xasprintf("%sXXXXXX", name);
					TT.fileout = xmkstemp(TT.tempname);
					// Set permissions of output file
					fstat(TT.filein, &statbuf);
					fchmod(TT.fileout, statbuf.st_mode);

					TT.linenum = 0;
					TT.hunknum = 0;
				}
			}

			TT.hunknum++;

			continue;
		}

		// If we didn't continue above, discard this line.
		free(patchline);
	}

	finish_oldfile();

	if (ENABLE_FEATURE_CLEAN_UP) {
		free(oldname);
		free(newname);
	}

	return TT.exitval;
}