summaryrefslogtreecommitdiff
path: root/editors/patch.c
blob: d5f6df2752241fce58bef1d06cade7ef6368fada (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
/* vi: set sw=4 ts=4: */
/*
 *  busybox patch applet to handle the unified diff format.
 *  Copyright (C) 2003 Glenn McGrath
 *
 *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 *
 *  This applet is written to work with patches generated by GNU diff,
 *  where there is equivalent functionality busybox patch shall behave
 *  as per GNU patch.
 *
 *  There is a SUSv3 specification for patch, however it looks to be
 *  incomplete, it doesnt even mention unified diff format.
 *  http://www.opengroup.org/onlinepubs/007904975/utilities/patch.html
 *
 *  Issues
 *   - Non-interactive
 *   - Patches must apply cleanly or patch (not just one hunk) will fail.
 *   - Reject file isnt saved
 */

#include "libbb.h"

static unsigned copy_lines(FILE *src_stream, FILE *dst_stream, unsigned lines_count)
{
	while (src_stream && lines_count) {
		char *line;
		line = xmalloc_fgets(src_stream);
		if (line == NULL) {
			break;
		}
		if (fputs(line, dst_stream) == EOF) {
			bb_perror_msg_and_die("error writing to new file");
		}
		free(line);
		lines_count--;
	}
	return lines_count;
}

/* If patch_level is -1 it will remove all directory names
 * char *line must be greater than 4 chars
 * returns NULL if the file doesnt exist or error
 * returns malloc'ed filename
 * NB: frees 1st argument!
 */
static char *extract_filename(char *line, int patch_level, const char *pat)
{
	char *temp = NULL, *filename_start_ptr = line + 4;

	if (strncmp(line, pat, 4) == 0) {
		/* Terminate string at end of source filename */
		line[strcspn(line, "\t\n\r")] = '\0';

		/* Skip over (patch_level) number of leading directories */
		while (patch_level--) {
			temp = strchr(filename_start_ptr, '/');
			if (!temp)
				break;
			filename_start_ptr = temp + 1;
		}
		temp = xstrdup(filename_start_ptr);
	}
	free(line);
	return temp;
}

int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int patch_main(int argc UNUSED_PARAM, char **argv)
{
	struct stat saved_stat;
	char *patch_line;
	FILE *patch_file;
	int patch_level;
	int ret = 0;
	char plus = '+';

	xfunc_error_retval = 2;
	{
		const char *p = "-1";
		const char *i = "-"; /* compat */
		if (getopt32(argv, "p:i:R", &p, &i) & 4)
			plus = '-';
		patch_level = xatoi(p); /* can be negative! */
		patch_file = xfopen_stdin(i);
	}

	patch_line = xmalloc_fgetline(patch_file);
	while (patch_line) {
		FILE *src_stream;
		FILE *dst_stream;
		//char *old_filename;
		char *new_filename;
		char *backup_filename;
		unsigned src_cur_line = 1;
		unsigned dst_cur_line = 0;
		unsigned dst_beg_line;
		unsigned bad_hunk_count = 0;
		unsigned hunk_count = 0;
		smallint copy_trailing_lines_flag = 0;

		/* Skip everything upto the "---" marker
		 * No need to parse the lines "Only in <dir>", and "diff <args>"
		 */
		do {
			/* Extract the filename used before the patch was generated */
			new_filename = extract_filename(patch_line, patch_level, "--- ");
			// was old_filename above
			patch_line = xmalloc_fgetline(patch_file);
			if (!patch_line) goto quit;
		} while (!new_filename);
		free(new_filename); // "source" filename is irrelevant

		new_filename = extract_filename(patch_line, patch_level, "+++ ");
		if (!new_filename) {
			bb_error_msg_and_die("invalid patch");
		}

		/* Get access rights from the file to be patched */
		if (stat(new_filename, &saved_stat) != 0) {
			char *slash = strrchr(new_filename, '/');
			if (slash) {
				/* Create leading directories */
				*slash = '\0';
				bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
				*slash = '/';
			}
			backup_filename = NULL;
			src_stream = NULL;
			saved_stat.st_mode = 0644;
		} else {
			backup_filename = xasprintf("%s.orig", new_filename);
			xrename(new_filename, backup_filename);
			src_stream = xfopen(backup_filename, "r");
		}
		dst_stream = xfopen(new_filename, "w");
		fchmod(fileno(dst_stream), saved_stat.st_mode);

		printf("patching file %s\n", new_filename);

		/* Handle all hunks for this file */
		patch_line = xmalloc_fgets(patch_file);
		while (patch_line) {
			unsigned count;
			unsigned src_beg_line;
			unsigned hunk_offset_start;
			unsigned src_last_line = 1;
			unsigned dst_last_line = 1;

			if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
			 && (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
			) {
				/* No more hunks for this file */
				break;
			}
			if (plus != '+') {
				/* reverse patch */
				unsigned tmp = src_last_line;
				src_last_line = dst_last_line;
				dst_last_line = tmp;
				tmp = src_beg_line;
				src_beg_line = dst_beg_line;
				dst_beg_line = tmp;
			}
			hunk_count++;

			if (src_beg_line && dst_beg_line) {
				/* Copy unmodified lines upto start of hunk */
				/* src_beg_line will be 0 if it's a new file */
				count = src_beg_line - src_cur_line;
				if (copy_lines(src_stream, dst_stream, count)) {
					bb_error_msg_and_die("bad src file");
				}
				src_cur_line += count;
				dst_cur_line += count;
				copy_trailing_lines_flag = 1;
			}
			src_last_line += hunk_offset_start = src_cur_line;
			dst_last_line += dst_cur_line;

			while (1) {
				free(patch_line);
				patch_line = xmalloc_fgets(patch_file);
				if (patch_line == NULL)
					break; /* EOF */
				if ((*patch_line != '-') && (*patch_line != '+')
				 && (*patch_line != ' ')
				) {
					break; /* End of hunk */
				}
				if (*patch_line != plus) { /* '-' or ' ' */
					char *src_line = NULL;
					if (src_cur_line == src_last_line)
						break;
					if (src_stream) {
						src_line = xmalloc_fgets(src_stream);
						if (src_line) {
							int diff = strcmp(src_line, patch_line + 1);
							src_cur_line++;
							free(src_line);
							if (diff)
								src_line = NULL;
						}
					}
					if (!src_line) {
						bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
						bad_hunk_count++;
						break;
					}
					if (*patch_line != ' ') { /* '-' */
						continue;
					}
				}
				if (dst_cur_line == dst_last_line)
					break;
				fputs(patch_line + 1, dst_stream);
				dst_cur_line++;
			} /* end of while loop handling one hunk */
		} /* end of while loop handling one file */

		/* Cleanup last patched file */
		if (copy_trailing_lines_flag) {
			copy_lines(src_stream, dst_stream, (unsigned)(-1));
		}
		if (src_stream) {
			fclose(src_stream);
		}
		fclose(dst_stream);
		if (bad_hunk_count) {
			ret = 1;
			bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
		} else {
			/* It worked, we can remove the backup */
			if (backup_filename) {
				unlink(backup_filename);
			}
			if ((dst_cur_line == 0) || (dst_beg_line == 0)) {
				/* The new patched file is empty, remove it */
				xunlink(new_filename);
				// /* old_filename and new_filename may be the same file */
				// unlink(old_filename);
			}
		}
		free(backup_filename);
		//free(old_filename);
		free(new_filename);
	} /* end of "while there are patch lines" */
 quit:
	/* 0 = SUCCESS
	 * 1 = Some hunks failed
	 * 2 = More serious problems (exited earlier)
	 */
	return ret;
}