aboutsummaryrefslogtreecommitdiff
path: root/toys/patch.c
blob: 62996538b7b8bc2077902d2bde205eff468c9815 (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
/* vi: set sw=4 ts=4:
 *
 * patch.c - Apply a "universal" diff.
 *
 * 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
 * -N ignore already applied
 * -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
 *
 * -E remove empty files --remove-empty-files
 * -f force (no questions asked)
 * -F fuzz (number, default 2)
 * [file] which file to patch

USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR|TOYFLAG_BIN))

config PATCH
	bool "patch"
	default y
	help
	  usage: patch [-i file] [-p depth] [-Ru]

	  Apply a unified diff to one or more files.

	  -i	Input file (defaults=stdin)
	  -p	number of '/' to strip from start of file paths (default=all)
	  -R	Reverse patch.
	  -u	Ignored (only handles "unified" diffs)

	  This version of patch only handles unified diffs, and only modifies
	  a file when all all hunks to that file apply.  Patch prints failed
	  hunks to stderr, and exits with nonzero status if any hunks fail.

	  A file compared against /dev/null (or with a date <= the epoch) is
	  created/deleted as appropriate.
*/

#include "toys.h"

DEFINE_GLOBALS(
	char *infile;
	long prefix;

	struct double_list *plines, *flines;
	long oldline, oldlen, newline, newlen, linenum;
	int context, state, filein, fileout, filepatch, hunknum;
	char *tempname, *oldname;
)

#define TT this.patch

#define FLAG_REVERSE 1
#define FLAG_PATHLEN 4

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

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

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

static void finish_oldfile(void)
{
	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
}

static void fail_hunk(void)
{
	if (!TT.plines) return;
	TT.plines->prev->next = 0;

	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
	toys.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;
	llist_free(TT.plines, do_line);
	TT.plines = NULL;
	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
	TT.filein = -1;
}

static void apply_hunk(void)
{
	struct double_list *plist, *buf = NULL, *check;
	int i = 0, backwards = 0, matcheof = 0,
		reverse = toys.optflags & FLAG_REVERSE;

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

	// Match EOF if there aren't as many ending context lines as beginning
	for (plist = TT.plines; plist; plist = plist->next) {
		if (plist->data[0]==' ') i++;
		else i = 0;
	}
	if (i < TT.context) matcheof++;

	// Search for a place to apply this hunk.  Match all context lines and
	// lines to be removed.
	plist = TT.plines;
	buf = NULL;
	i = 0;

	// Start of for loop
	if (TT.context) for (;;) {
		char *data = get_line(TT.filein);

		TT.linenum++;

		// Skip lines of the hunk we'd be adding.
		while (plist && *plist->data == "+-"[reverse]) {
			if (data && !strcmp(data, plist->data+1)) {
				if (++backwards == TT.context)
					fdprintf(2,"Possibly reversed hunk %d at %ld\n",
						TT.hunknum, TT.linenum);
			} else backwards=0;
			plist = plist->next;
		}

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

			// File ended before we found a place for this hunk.
			fail_hunk();
			goto done;
		}
		check = dlist_add(&buf, data);

		// todo: teach the strcmp() to ignore whitespace.

		for (;;) {
			// If we hit the end of a hunk that needed EOF and this isn't EOF,
			// or next line doesn't match, flush first line of buffered data and
			// recheck match until we find a new match or run out of buffer.
	
			if (!plist || strcmp(check->data, plist->data+1)) {
				// First line isn't a match, write it out.
				TT.state = 1;
				check = llist_pop(&buf);
				check->prev->next = buf;
				buf->prev = check->prev;
				do_line(check);
				plist = TT.plines;

				// Out of buffered lines?
				if (check==buf) {
					buf = 0;
					break;
				}
				check = buf;
			} else {
				// This line matches.  Advance plist, detect successful match.
				plist = plist->next;
				if (!plist && !matcheof) goto out;
				check = check->next;
				if (check == buf) break;
			}
		}
	}
out:
	// Got it.  Emit changed data.
	TT.state = "-+"[reverse];
	llist_free(TT.plines, do_line);
	TT.plines = NULL;
done:
	TT.state = 0;
	if (buf) {
		buf->prev->next = NULL;
		llist_free(buf, do_line);
	}
}

// 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

void patch_main(void)
{
	if (TT.infile) TT.filepatch = xopen(TT.infile, O_RDONLY);
	TT.filein = TT.fileout = -1;

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

		patchline = get_line(TT.filepatch);
		if (!patchline) break;

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

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

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

				if (!TT.oldlen && !TT.newlen) apply_hunk();
				continue;
			}
			fail_hunk();
			TT.state = 0;
			continue;
		}

		// Open a new file?
		if (!strncmp("--- ", patchline, 4)) {
			char *s;
			int i;

			free(TT.oldname);

			// 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 && i<=1970)
				TT.oldname = xstrdup("/dev/null");
			else {
				*s = 0;
				TT.oldname = xstrdup(patchline+4);
			}
		} else if (!strncmp("+++ ", patchline, 4)) {
			int i = 0, del = 0;
			char *s, *start;

			finish_oldfile();

			// Trim date from end of filename (if any).  We don't care.
			for (s = start = patchline+4; *s && *s!='\t'; s++)
				if (*s=='\\' && s[1]) s++;
			if (!strncmp(s, "\t1969-12-31", 10)) start = "/dev/null";
			*s = 0;

			// If new file is /dev/null (before -p), we're deleting oldname
			if (!strcmp(start, "/dev/null")) {
				start = TT.oldname;
				del++;
			} else start = patchline+4;
				
			// handle -p path truncation.
			for (s = start; *s;) {
				if ((toys.optflags & FLAG_PATHLEN) && TT.prefix == i) break;
				if (*(s++)=='/') {
					start = s;
					i++;
				}
			}

			if (del) {
				printf("removing %s\n", start);
				xunlink(start);
			// If we've got a file to open, do so.
			} else if (!(toys.optflags & FLAG_PATHLEN) || i <= TT.prefix) {
				// If the old file was null, we're creating a new one.
				if (!strcmp(TT.oldname, "/dev/null")) {
					printf("creating %s\n", start);
					s = strrchr(start, '/');
					if (s) {
						*s = 0;
						xmkpath(start, -1);
						*s = '/';
					}
					TT.filein = xcreate(start, O_CREAT|O_EXCL|O_RDWR, 0666);
				} else {
					printf("patching %s\n", start);
					TT.filein = xopen(start, O_RDWR);
				}
				TT.fileout = copy_tempfile(TT.filein, start, &TT.tempname);
				TT.state = 1;
				TT.context = 0;
				TT.linenum = 0;
				TT.hunknum = 0;
			}

		// Start a new hunk?
		// Test filein rather than state to report only the first failed hunk.
		} else if (TT.filein!=-1 && !strncmp("@@ -", patchline, 4) &&
			4 == sscanf(patchline+4, "%ld,%ld +%ld,%ld", &TT.oldline,
				&TT.oldlen, &TT.newline, &TT.newlen))
		{
			TT.context = 0;
			TT.hunknum++;
			TT.state = 2;
			continue;
		}

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

	finish_oldfile();

	if (CFG_TOYBOX_FREE) {
		close(TT.filepatch);
		free(TT.oldname);
	}
}