summaryrefslogtreecommitdiff
path: root/editors/patch.c
blob: 980c37f400e52da09d35ebfc0f2fc3a4be5ce584 (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
/* vi: set sw=4 ts=4: */
/*
 *  busybox patch applet to handle the unified diff format.
 *  Copyright (C) 2003 Glenn McGrath <bug1@iinet.net.au>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *
 *
 *  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 the hunk will fail.
 *   - Reject file isnt saved
 *   -
 */

#include <getopt.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "busybox.h"

static int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
{
	int i = 0;

	while (src_stream && (i < lines_count)) {
		char *line;
		line = bb_get_line_from_file(src_stream);
		if (line == NULL) {
			break;
		}
		if (fputs(line, dest_stream) == EOF) {
			bb_perror_msg_and_die("Error writing to new file");
		}
		free(line);

		i++;
	}
	return(i);
}

/* 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
 */

static unsigned char *extract_filename(char *line, unsigned short patch_level)
{
	char *filename_start_ptr = line + 4;
	int i;

	/* Terminate string at end of source filename */
	{
		char *line_ptr;
		line_ptr = strchr(filename_start_ptr, '\t');
		if (!line_ptr) {
			bb_perror_msg("Malformed line %s", line);
			return(NULL);
		}
		*line_ptr = '\0';
	}

	/* Skip over (patch_level) number of leading directories */
	for (i = 0; i < patch_level; i++) {
		char *dirname_ptr;

		dirname_ptr = strchr(filename_start_ptr, '/');
		if (!dirname_ptr) {
			break;
		}
		filename_start_ptr = dirname_ptr + 1;
	}

	return(bb_xstrdup(filename_start_ptr));
}

static int file_doesnt_exist(const char *filename)
{
	struct stat statbuf;
	return(stat(filename, &statbuf));
}

extern int patch_main(int argc, char **argv)
{
	unsigned int patch_level = -1;
	char *patch_line;
	int ret;
	FILE *patch_file = NULL;

	{
		char *p, *i;
		ret = bb_getopt_ulflags(argc, argv, "p:i:", &p, &i);
		if (ret & 1)
			patch_level = bb_xgetularg10_bnd(p, -1, USHRT_MAX);
		if (ret & 2) {
			patch_file = bb_xfopen(i, "r");
		}
		ret = 0;
	}

	if (!patch_file)
		patch_file = stdin;

	patch_line = bb_get_line_from_file(patch_file);
	while (patch_line) {
		FILE *src_stream;
		FILE *dst_stream;
		char *original_filename;
		char *new_filename;
		char *backup_filename;
		unsigned int src_cur_line = 1;
		unsigned int dest_cur_line = 0;
		unsigned int dest_beg_line;
		unsigned int bad_hunk_count = 0;
		unsigned int hunk_count = 0;
		char copy_trailing_lines_flag = 0;

		/* Skip everything upto the "---" marker
		 * No need to parse the lines "Only in <dir>", and "diff <args>"
		 */
		while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
			free(patch_line);
			patch_line = bb_get_line_from_file(patch_file);
		}

		/* Extract the filename used before the patch was generated */
		original_filename = extract_filename(patch_line, patch_level);
		free(patch_line);

		patch_line = bb_get_line_from_file(patch_file);
		if (strncmp(patch_line, "+++ ", 4) != 0) {
			ret = 2;
			bb_error_msg("Invalid patch");
			continue;
		}
		new_filename = extract_filename(patch_line, patch_level);
		free(patch_line);

		if (file_doesnt_exist(new_filename)) {
			char *line_ptr;
			/* Create leading directories */
			line_ptr = strrchr(new_filename, '/');
			if (line_ptr) {
				*line_ptr = '\0';
				bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
				*line_ptr = '/';
			}
			dst_stream = bb_xfopen(new_filename, "w+");
			backup_filename = NULL;
		} else {
			backup_filename = xmalloc(strlen(new_filename) + 6);
			strcpy(backup_filename, new_filename);
			strcat(backup_filename, ".orig");
			if (rename(new_filename, backup_filename) == -1) {
				bb_perror_msg_and_die("Couldnt create file %s", backup_filename);
			}
			dst_stream = bb_xfopen(new_filename, "w");
		}

		if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
			src_stream = NULL;
		} else {
			if (strcmp(original_filename, new_filename) == 0) {
				src_stream = bb_xfopen(backup_filename, "r");
			} else {
				src_stream = bb_xfopen(original_filename, "r");
			}
		}

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

		/* Handle each hunk */
		patch_line = bb_get_line_from_file(patch_file);
		while (patch_line) {
			unsigned int count;
			unsigned int src_beg_line;
			unsigned int unused;
			unsigned int hunk_offset_start = 0;
			int hunk_error = 0;

			/* This bit should be improved */
			if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
				(sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
				(sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
				/* No more hunks for this file */
				break;
			}
			free(patch_line);
			hunk_count++;

			if (src_beg_line && dest_beg_line) {
				/* Copy unmodified lines upto start of hunk */
				/* src_beg_line will be 0 if its a new file */
				count = src_beg_line - src_cur_line;
				if (copy_lines(src_stream, dst_stream, count) != count) {
					bb_error_msg_and_die("Bad src file");
				}
				src_cur_line += count;
				dest_cur_line += count;
				copy_trailing_lines_flag = 1;
			}
			hunk_offset_start = src_cur_line;

			while ((patch_line = bb_get_line_from_file(patch_file)) != NULL) {
				if ((*patch_line == '-') || (*patch_line == ' ')) {
					char *src_line = NULL;
					if (src_stream) {
						src_line = bb_get_line_from_file(src_stream);
						if (!src_line) {
							hunk_error++;
							break;
						} else {
							src_cur_line++;
						}
						if (strcmp(src_line, patch_line + 1) != 0) {
							bb_error_msg("Hunk #%d FAILED at %d.", hunk_count, hunk_offset_start);
							hunk_error++;
							free(patch_line);
							break;
						}
						free(src_line);
					}
					if (*patch_line == ' ') {
						fputs(patch_line + 1, dst_stream);
						dest_cur_line++;
					}
				} else if (*patch_line == '+') {
					fputs(patch_line + 1, dst_stream);
					dest_cur_line++;
				} else {
					break;
				}
				free(patch_line);
			}
			if (hunk_error) {
				bad_hunk_count++;
			}
		}

		/* Cleanup last patched file */
		if (copy_trailing_lines_flag) {
			copy_lines(src_stream, dst_stream, -1);
		}
		if (src_stream) {
			fclose(src_stream);
		}
		if (dst_stream) {
			fclose(dst_stream);
		}
		if (bad_hunk_count) {
			if (!ret) {
				ret = 1;
			}
			bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
		} else {
			/* It worked, we can remove the backup */
			if (backup_filename) {
				unlink(backup_filename);
			}
			if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
				/* The new patched file is empty, remove it */
				if (unlink(new_filename) == -1) {
					bb_perror_msg_and_die("Couldnt remove file %s", new_filename);
				}
				if (unlink(original_filename) == -1) {
					bb_perror_msg_and_die("Couldnt remove original file %s", new_filename);
				}
			}
		}
	}

	/* 0 = SUCCESS
	 * 1 = Some hunks failed
	 * 2 = More serious problems
	 */
	return(ret);
}