1/* Adapted from toybox's patch. */
2
3/* vi: set sw=4 ts=4:
4 *
5 * patch.c - Apply a "universal" diff.
6 *
7 * Copyright 2007 Rob Landley <rob@landley.net>
8 *
9 * see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
10 * (But only does -u, because who still cares about "ed"?)
11 *
12 * TODO:
13 * -b backup
14 * -l treat all whitespace as a single space
15 * -d chdir first
16 * -D define wrap #ifdef and #ifndef around changes
17 * -o outfile output here instead of in place
18 * -r rejectfile write rejected hunks to this file
19 *
20 * -E remove empty files --remove-empty-files
21 * -f force (no questions asked)
22 * -F fuzz (number, default 2)
23 * [file] which file to patch
24
25USE_PATCH(NEWTOY(patch, USE_TOYBOX_DEBUG("x")"up#i:R", TOYFLAG_USR|TOYFLAG_BIN))
26
27config PATCH
28	bool "patch"
29	default y
30	help
31	  usage: patch [-i file] [-p depth] [-Ru]
32
33	  Apply a unified diff to one or more files.
34
35	  -i	Input file (defaults=stdin)
36	  -p	number of '/' to strip from start of file paths (default=all)
37	  -R	Reverse patch.
38	  -u	Ignored (only handles "unified" diffs)
39
40	  This version of patch only handles unified diffs, and only modifies
41	  a file when all all hunks to that file apply.  Patch prints failed
42	  hunks to stderr, and exits with nonzero status if any hunks fail.
43
44	  A file compared against /dev/null (or with a date <= the epoch) is
45	  created/deleted as appropriate.
46*/
47#include "libbb.h"
48
49struct double_list {
50	struct double_list *next;
51	struct double_list *prev;
52	char *data;
53};
54
55// Return the first item from the list, advancing the list (which must be called
56// as &list)
57static
58void *TOY_llist_pop(void *list)
59{
60	// I'd use a void ** for the argument, and even accept the typecast in all
61	// callers as documentation you need the &, except the stupid compiler
62	// would then scream about type-punned pointers.  Screw it.
63	void **llist = (void **)list;
64	void **next = (void **)*llist;
65	*llist = *next;
66
67	return (void *)next;
68}
69
70// Free all the elements of a linked list
71// if freeit!=NULL call freeit() on each element before freeing it.
72static
73void TOY_llist_free(void *list, void (*freeit)(void *data))
74{
75	while (list) {
76		void *pop = TOY_llist_pop(&list);
77		if (freeit) freeit(pop);
78		else free(pop);
79
80		// End doubly linked list too.
81		if (list==pop) break;
82	}
83}
84//Override bbox's names
85#define llist_pop TOY_llist_pop
86#define llist_free TOY_llist_free
87
88// Add an entry to the end off a doubly linked list
89static
90struct double_list *dlist_add(struct double_list **list, char *data)
91{
92	struct double_list *line = xmalloc(sizeof(struct double_list));
93
94	line->data = data;
95	if (*list) {
96		line->next = *list;
97		line->prev = (*list)->prev;
98		(*list)->prev->next = line;
99		(*list)->prev = line;
100	} else *list = line->next = line->prev = line;
101
102	return line;
103}
104
105// Ensure entire path exists.
106// If mode != -1 set permissions on newly created dirs.
107// Requires that path string be writable (for temporary null terminators).
108static
109void xmkpath(char *path, int mode)
110{
111	char *p, old;
112	mode_t mask;
113	int rc;
114	struct stat st;
115
116	for (p = path; ; p++) {
117		if (!*p || *p == '/') {
118			old = *p;
119			*p = rc = 0;
120			if (stat(path, &st) || !S_ISDIR(st.st_mode)) {
121				if (mode != -1) {
122					mask = umask(0);
123					rc = mkdir(path, mode);
124					umask(mask);
125				} else rc = mkdir(path, 0777);
126			}
127			*p = old;
128			if(rc) bb_perror_msg_and_die("mkpath '%s'", path);
129		}
130		if (!*p) break;
131	}
132}
133
134// Slow, but small.
135static
136char *get_rawline(int fd, long *plen, char end)
137{
138	char c, *buf = NULL;
139	long len = 0;
140
141	for (;;) {
142		if (1>read(fd, &c, 1)) break;
143		if (!(len & 63)) buf=xrealloc(buf, len+65);
144		if ((buf[len++]=c) == end) break;
145	}
146	if (buf) buf[len]=0;
147	if (plen) *plen = len;
148
149	return buf;
150}
151
152static
153char *get_line(int fd)
154{
155	long len;
156	char *buf = get_rawline(fd, &len, '\n');
157
158	if (buf && buf[--len]=='\n') buf[len]=0;
159
160	return buf;
161}
162
163// Copy the rest of in to out and close both files.
164static
165void xsendfile(int in, int out)
166{
167	long len;
168	char buf[4096];
169
170	if (in<0) return;
171	for (;;) {
172		len = safe_read(in, buf, 4096);
173		if (len<1) break;
174		xwrite(out, buf, len);
175	}
176}
177
178// Copy the rest of the data and replace the original with the copy.
179static
180void replace_tempfile(int fdin, int fdout, char **tempname)
181{
182	char *temp = xstrdup(*tempname);
183
184	temp[strlen(temp)-6]=0;
185	if (fdin != -1) {
186		xsendfile(fdin, fdout);
187		xclose(fdin);
188	}
189	xclose(fdout);
190	rename(*tempname, temp);
191	free(*tempname);
192	free(temp);
193	*tempname = NULL;
194}
195
196// Open a temporary file to copy an existing file into.
197static
198int copy_tempfile(int fdin, char *name, char **tempname)
199{
200	struct stat statbuf;
201	int fd;
202
203	*tempname = xasprintf("%sXXXXXX", name);
204	fd = mkstemp(*tempname);
205	if(-1 == fd) bb_perror_msg_and_die("no temp file");
206
207	// Set permissions of output file
208	fstat(fdin, &statbuf);
209	fchmod(fd, statbuf.st_mode);
210
211	return fd;
212}
213
214// Abort the copy and delete the temporary file.
215static
216void delete_tempfile(int fdin, int fdout, char **tempname)
217{
218	close(fdin);
219	close(fdout);
220	unlink(*tempname);
221	free(*tempname);
222	*tempname = NULL;
223}
224
225
226
227struct globals {
228	char *infile;
229	long prefix;
230
231	struct double_list *current_hunk;
232	long oldline, oldlen, newline, newlen;
233	long linenum;
234	int context, state, filein, fileout, filepatch, hunknum;
235	char *tempname;
236
237	// was toys.foo:
238	int exitval;
239};
240#define TT (*ptr_to_globals)
241#define INIT_TT() do { \
242	SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
243} while (0)
244
245
246#define FLAG_STR "Rup:i:Nx"
247/* FLAG_REVERSE must be == 1! Code uses this fact. */
248#define FLAG_REVERSE (1 << 0)
249#define FLAG_u       (1 << 1)
250#define FLAG_PATHLEN (1 << 2)
251#define FLAG_INPUT   (1 << 3)
252#define FLAG_IGNORE  (1 << 4)
253//non-standard:
254#define FLAG_DEBUG   (1 << 5)
255
256// Dispose of a line of input, either by writing it out or discarding it.
257
258// state < 2: just free
259// state = 2: write whole line to stderr
260// state = 3: write whole line to fileout
261// state > 3: write line+1 to fileout when *line != state
262
263#define PATCH_DEBUG (option_mask32 & FLAG_DEBUG)
264
265static void do_line(void *data)
266{
267	struct double_list *dlist = (struct double_list *)data;
268
269	if (TT.state>1 && *dlist->data != TT.state)
270		fdprintf(TT.state == 2 ? 2 : TT.fileout,
271			"%s\n", dlist->data+(TT.state>3 ? 1 : 0));
272
273	if (PATCH_DEBUG) fdprintf(2, "DO %d: %s\n", TT.state, dlist->data);
274
275	free(dlist->data);
276	free(data);
277}
278
279static void finish_oldfile(void)
280{
281	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
282	TT.fileout = TT.filein = -1;
283}
284
285static void fail_hunk(void)
286{
287	if (!TT.current_hunk) return;
288	TT.current_hunk->prev->next = 0;
289
290	fdprintf(2, "Hunk %d FAILED %ld/%ld.\n", TT.hunknum, TT.oldline, TT.newline);
291	TT.exitval = 1;
292
293	// If we got to this point, we've seeked to the end.  Discard changes to
294	// this file and advance to next file.
295
296	TT.state = 2;
297	llist_free(TT.current_hunk, do_line);
298	TT.current_hunk = NULL;
299	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
300	TT.state = 0;
301}
302
303// Given a hunk of a unified diff, make the appropriate change to the file.
304// This does not use the location information, but instead treats a hunk
305// as a sort of regex.  Copies data from input to output until it finds
306// the change to be made, then outputs the changed data and returns.
307// (Finding EOF first is an error.)  This is a single pass operation, so
308// multiple hunks must occur in order in the file.
309
310static int apply_one_hunk(void)
311{
312	struct double_list *plist, *buf = NULL, *check;
313	int matcheof = 0, reverse = option_mask32 & FLAG_REVERSE, backwarn = 0;
314	/* Do we try "dummy" revert to check whether
315	 * to silently skip this hunk? Used to implement -N.
316	 */
317	int dummy_revert = 0;
318
319	// Break doubly linked list so we can use singly linked traversal function.
320	TT.current_hunk->prev->next = NULL;
321
322	// Match EOF if there aren't as many ending context lines as beginning
323	for (plist = TT.current_hunk; plist; plist = plist->next) {
324		if (plist->data[0]==' ') matcheof++;
325		else matcheof = 0;
326		if (PATCH_DEBUG) fdprintf(2, "HUNK:%s\n", plist->data);
327	}
328	matcheof = matcheof < TT.context;
329
330	if (PATCH_DEBUG) fdprintf(2,"MATCHEOF=%c\n", matcheof ? 'Y' : 'N');
331
332	// Loop through input data searching for this hunk.  Match all context
333	// lines and all lines to be removed until we've found the end of a
334	// complete hunk.
335	plist = TT.current_hunk;
336	buf = NULL;
337	if (TT.context) for (;;) {
338		char *data = get_line(TT.filein);
339
340		TT.linenum++;
341
342		// Figure out which line of hunk to compare with next.  (Skip lines
343		// of the hunk we'd be adding.)
344		while (plist && *plist->data == "+-"[reverse]) {
345			if (data && !strcmp(data, plist->data+1)) {
346				if (!backwarn) {
347					backwarn++;
348					if (option_mask32 & FLAG_IGNORE) {
349						dummy_revert = 1;
350						reverse ^= 1;
351						continue;
352					}
353					fdprintf(2,"Possibly reversed hunk %d at %ld\n",
354						TT.hunknum, TT.linenum);
355				}
356			}
357			plist = plist->next;
358		}
359
360		// Is this EOF?
361		if (!data) {
362			if (PATCH_DEBUG) fdprintf(2, "INEOF\n");
363
364			// Does this hunk need to match EOF?
365			if (!plist && matcheof) break;
366
367			// File ended before we found a place for this hunk.
368			fail_hunk();
369			goto done;
370		} else if (PATCH_DEBUG) fdprintf(2, "IN: %s\n", data);
371		check = dlist_add(&buf, data);
372
373		// Compare this line with next expected line of hunk.
374		// todo: teach the strcmp() to ignore whitespace.
375
376		// A match can fail because the next line doesn't match, or because
377		// we hit the end of a hunk that needed EOF, and this isn't EOF.
378
379		// If match failed, flush first line of buffered data and
380		// recheck buffered data for a new match until we find one or run
381		// out of buffer.
382
383		for (;;) {
384			if (!plist || strcmp(check->data, plist->data+1)) {
385				// Match failed.  Write out first line of buffered data and
386				// recheck remaining buffered data for a new match.
387
388				if (PATCH_DEBUG)
389					fdprintf(2, "NOT: %s\n", plist->data);
390
391				TT.state = 3;
392				check = llist_pop(&buf);
393				check->prev->next = buf;
394				buf->prev = check->prev;
395				do_line(check);
396				plist = TT.current_hunk;
397
398				// If we've reached the end of the buffer without confirming a
399				// match, read more lines.
400				if (check==buf) {
401					buf = 0;
402					break;
403				}
404				check = buf;
405			} else {
406				if (PATCH_DEBUG)
407					fdprintf(2, "MAYBE: %s\n", plist->data);
408				// This line matches.  Advance plist, detect successful match.
409				plist = plist->next;
410				if (!plist && !matcheof) goto out;
411				check = check->next;
412				if (check == buf) break;
413			}
414		}
415	}
416out:
417	// We have a match.  Emit changed data.
418	TT.state = "-+"[reverse ^ dummy_revert];
419	llist_free(TT.current_hunk, do_line);
420	TT.current_hunk = NULL;
421	TT.state = 1;
422done:
423	if (buf) {
424		buf->prev->next = NULL;
425		llist_free(buf, do_line);
426	}
427
428	return TT.state;
429}
430
431// Read a patch file and find hunks, opening/creating/deleting files.
432// Call apply_one_hunk() on each hunk.
433
434// state 0: Not in a hunk, look for +++.
435// state 1: Found +++ file indicator, look for @@
436// state 2: In hunk: counting initial context lines
437// state 3: In hunk: getting body
438
439int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
440int patch_main(int argc UNUSED_PARAM, char **argv)
441{
442	int opts;
443	int reverse, state = 0;
444	char *oldname = NULL, *newname = NULL;
445	char *opt_p, *opt_i;
446
447	INIT_TT();
448
449	opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
450	argv += optind;
451	reverse = opts & FLAG_REVERSE;
452	TT.prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
453	TT.filein = TT.fileout = -1;
454	if (opts & FLAG_INPUT) {
455		TT.filepatch = xopen_stdin(opt_i);
456	} else {
457		if (argv[0] && argv[1]) {
458			TT.filepatch = xopen_stdin(argv[1]);
459		}
460	}
461	if (argv[0]) {
462		oldname = xstrdup(argv[0]);
463		newname = xstrdup(argv[0]);
464	}
465
466	// Loop through the lines in the patch
467	for(;;) {
468		char *patchline;
469
470		patchline = get_line(TT.filepatch);
471		if (!patchline) break;
472
473		// Other versions of patch accept damaged patches,
474		// so we need to also.
475		if (!*patchline) {
476			free(patchline);
477			patchline = xstrdup(" ");
478		}
479
480		// Are we assembling a hunk?
481		if (state >= 2) {
482			if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
483				dlist_add(&TT.current_hunk, patchline);
484
485				if (*patchline != '+') TT.oldlen--;
486				if (*patchline != '-') TT.newlen--;
487
488				// Context line?
489				if (*patchline==' ' && state==2) TT.context++;
490				else state=3;
491
492				// If we've consumed all expected hunk lines, apply the hunk.
493
494				if (!TT.oldlen && !TT.newlen) state = apply_one_hunk();
495				continue;
496			}
497			fail_hunk();
498			state = 0;
499			continue;
500		}
501
502		// Open a new file?
503		if (!strncmp("--- ", patchline, 4) || !strncmp("+++ ", patchline, 4)) {
504			char *s, **name = reverse ? &newname : &oldname;
505			int i;
506
507			if (*patchline == '+') {
508				name = reverse ? &oldname : &newname;
509				state = 1;
510			}
511
512			finish_oldfile();
513
514			if (!argv[0]) {
515				free(*name);
516				// Trim date from end of filename (if any).  We don't care.
517				for (s = patchline+4; *s && *s!='\t'; s++)
518					if (*s=='\\' && s[1]) s++;
519				i = atoi(s);
520				if (i>1900 && i<=1970)
521					*name = xstrdup("/dev/null");
522				else {
523					*s = 0;
524					*name = xstrdup(patchline+4);
525				}
526			}
527
528			// We defer actually opening the file because svn produces broken
529			// patches that don't signal they want to create a new file the
530			// way the patch man page says, so you have to read the first hunk
531			// and _guess_.
532
533		// Start a new hunk?  Usually @@ -oldline,oldlen +newline,newlen @@
534		// but a missing ,value means the value is 1.
535		} else if (state == 1 && !strncmp("@@ -", patchline, 4)) {
536			int i;
537			char *s = patchline+4;
538
539			// Read oldline[,oldlen] +newline[,newlen]
540
541			TT.oldlen = TT.newlen = 1;
542			TT.oldline = strtol(s, &s, 10);
543			if (*s == ',') TT.oldlen=strtol(s+1, &s, 10);
544			TT.newline = strtol(s+2, &s, 10);
545			if (*s == ',') TT.newlen = strtol(s+1, &s, 10);
546
547			TT.context = 0;
548			state = 2;
549
550			// If this is the first hunk, open the file.
551			if (TT.filein == -1) {
552				int oldsum, newsum, del = 0;
553				char *name;
554
555 				oldsum = TT.oldline + TT.oldlen;
556				newsum = TT.newline + TT.newlen;
557
558				name = reverse ? oldname : newname;
559
560				// We're deleting oldname if new file is /dev/null (before -p)
561				// or if new hunk is empty (zero context) after patching
562				if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum))
563				{
564					name = reverse ? newname : oldname;
565					del++;
566				}
567
568				// handle -p path truncation.
569				for (i=0, s = name; *s;) {
570					if ((option_mask32 & FLAG_PATHLEN) && TT.prefix == i) break;
571					if (*(s++)=='/') {
572						name = s;
573						i++;
574					}
575				}
576
577				if (del) {
578					printf("removing %s\n", name);
579					xunlink(name);
580					state = 0;
581				// If we've got a file to open, do so.
582				} else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
583					// If the old file was null, we're creating a new one.
584					if (!strcmp(oldname, "/dev/null") || !oldsum) {
585						printf("creating %s\n", name);
586						s = strrchr(name, '/');
587						if (s) {
588							*s = 0;
589							xmkpath(name, -1);
590							*s = '/';
591						}
592						TT.filein = xopen3(name, O_CREAT|O_EXCL|O_RDWR, 0666);
593					} else {
594						printf("patching file %s\n", name);
595						TT.filein = xopen(name, O_RDWR);
596					}
597					TT.fileout = copy_tempfile(TT.filein, name, &TT.tempname);
598					TT.linenum = 0;
599					TT.hunknum = 0;
600				}
601			}
602
603			TT.hunknum++;
604
605			continue;
606		}
607
608		// If we didn't continue above, discard this line.
609		free(patchline);
610	}
611
612	finish_oldfile();
613
614	if (ENABLE_FEATURE_CLEAN_UP) {
615		close(TT.filepatch);
616		free(oldname);
617		free(newname);
618	}
619
620	return TT.exitval;
621}
622