add usefun info on SIGINT handling peculiarities
[oweals/busybox.git] / editors / patch.c
1 /* vi: set sw=4 ts=4: */
2 /*
3  *  busybox patch applet to handle the unified diff format.
4  *  Copyright (C) 2003 Glenn McGrath <bug1@iinet.net.au>
5  *
6  *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
7  *
8  *  This applet is written to work with patches generated by GNU diff,
9  *  where there is equivalent functionality busybox patch shall behave
10  *  as per GNU patch.
11  *
12  *  There is a SUSv3 specification for patch, however it looks to be
13  *  incomplete, it doesnt even mention unified diff format.
14  *  http://www.opengroup.org/onlinepubs/007904975/utilities/patch.html
15  *
16  *  Issues
17  *   - Non-interactive
18  *   - Patches must apply cleanly or the hunk will fail.
19  *   - Reject file isnt saved
20  *   -
21  */
22
23 #include <getopt.h>
24 #include <string.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include "busybox.h"
28
29 static unsigned int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
30 {
31         unsigned int i = 0;
32
33         while (src_stream && (i < lines_count)) {
34                 char *line;
35                 line = xmalloc_fgets(src_stream);
36                 if (line == NULL) {
37                         break;
38                 }
39                 if (fputs(line, dest_stream) == EOF) {
40                         bb_perror_msg_and_die("error writing to new file");
41                 }
42                 free(line);
43
44                 i++;
45         }
46         return(i);
47 }
48
49 /* If patch_level is -1 it will remove all directory names
50  * char *line must be greater than 4 chars
51  * returns NULL if the file doesnt exist or error
52  * returns malloc'ed filename
53  */
54
55 static char *extract_filename(char *line, int patch_level)
56 {
57         char *temp, *filename_start_ptr = line + 4;
58         int i;
59
60         /* Terminate string at end of source filename */
61         temp = strchr(filename_start_ptr, '\t');
62         if (temp) *temp = 0;
63
64         /* skip over (patch_level) number of leading directories */
65         for (i = 0; i < patch_level; i++) {
66                 if(!(temp = strchr(filename_start_ptr, '/'))) break;
67                 filename_start_ptr = temp + 1;
68         }
69
70         return(xstrdup(filename_start_ptr));
71 }
72
73 static int file_doesnt_exist(const char *filename)
74 {
75         struct stat statbuf;
76         return(stat(filename, &statbuf));
77 }
78
79 int patch_main(int argc, char **argv)
80 {
81         int patch_level = -1;
82         char *patch_line;
83         int ret;
84         FILE *patch_file = NULL;
85
86         {
87                 char *p, *i;
88                 ret = getopt32(argc, argv, "p:i:", &p, &i);
89                 if (ret & 1)
90                         patch_level = xatol_range(p, -1, USHRT_MAX);
91                 if (ret & 2) {
92                         patch_file = xfopen(i, "r");
93                 } else {
94                         patch_file = stdin;
95                 }
96                 ret = 0;
97         }
98
99         patch_line = xmalloc_fgets(patch_file);
100         while (patch_line) {
101                 FILE *src_stream;
102                 FILE *dst_stream;
103                 char *original_filename;
104                 char *new_filename;
105                 char *backup_filename;
106                 unsigned int src_cur_line = 1;
107                 unsigned int dest_cur_line = 0;
108                 unsigned int dest_beg_line;
109                 unsigned int bad_hunk_count = 0;
110                 unsigned int hunk_count = 0;
111                 char copy_trailing_lines_flag = 0;
112
113                 /* Skip everything upto the "---" marker
114                  * No need to parse the lines "Only in <dir>", and "diff <args>"
115                  */
116                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
117                         free(patch_line);
118                         patch_line = xmalloc_fgets(patch_file);
119                 }
120
121                 /* Extract the filename used before the patch was generated */
122                 original_filename = extract_filename(patch_line, patch_level);
123                 free(patch_line);
124
125                 patch_line = xmalloc_fgets(patch_file);
126                 if (strncmp(patch_line, "+++ ", 4) != 0) {
127                         ret = 2;
128                         bb_error_msg("invalid patch");
129                         continue;
130                 }
131                 new_filename = extract_filename(patch_line, patch_level);
132                 free(patch_line);
133
134                 if (file_doesnt_exist(new_filename)) {
135                         char *line_ptr;
136                         /* Create leading directories */
137                         line_ptr = strrchr(new_filename, '/');
138                         if (line_ptr) {
139                                 *line_ptr = '\0';
140                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
141                                 *line_ptr = '/';
142                         }
143                         dst_stream = xfopen(new_filename, "w+");
144                         backup_filename = NULL;
145                 } else {
146                         backup_filename = xmalloc(strlen(new_filename) + 6);
147                         strcpy(backup_filename, new_filename);
148                         strcat(backup_filename, ".orig");
149                         if (rename(new_filename, backup_filename) == -1) {
150                                 bb_perror_msg_and_die("cannot create file %s",
151                                                 backup_filename);
152                         }
153                         dst_stream = xfopen(new_filename, "w");
154                 }
155
156                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
157                         src_stream = NULL;
158                 } else {
159                         if (strcmp(original_filename, new_filename) == 0) {
160                                 src_stream = xfopen(backup_filename, "r");
161                         } else {
162                                 src_stream = xfopen(original_filename, "r");
163                         }
164                 }
165
166                 printf("patching file %s\n", new_filename);
167
168                 /* Handle each hunk */
169                 patch_line = xmalloc_fgets(patch_file);
170                 while (patch_line) {
171                         unsigned int count;
172                         unsigned int src_beg_line;
173                         unsigned int unused;
174                         unsigned int hunk_offset_start = 0;
175                         int hunk_error = 0;
176
177                         /* This bit should be improved */
178                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
179                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
180                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
181                                 /* No more hunks for this file */
182                                 break;
183                         }
184                         free(patch_line);
185                         hunk_count++;
186
187                         if (src_beg_line && dest_beg_line) {
188                                 /* Copy unmodified lines upto start of hunk */
189                                 /* src_beg_line will be 0 if its a new file */
190                                 count = src_beg_line - src_cur_line;
191                                 if (copy_lines(src_stream, dst_stream, count) != count) {
192                                         bb_error_msg_and_die("bad src file");
193                                 }
194                                 src_cur_line += count;
195                                 dest_cur_line += count;
196                                 copy_trailing_lines_flag = 1;
197                         }
198                         hunk_offset_start = src_cur_line;
199
200                         while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
201                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
202                                         char *src_line = NULL;
203                                         if (src_stream) {
204                                                 src_line = xmalloc_fgets(src_stream);
205                                                 if (!src_line) {
206                                                         hunk_error++;
207                                                         break;
208                                                 } else {
209                                                         src_cur_line++;
210                                                 }
211                                                 if (strcmp(src_line, patch_line + 1) != 0) {
212                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
213                                                         hunk_error++;
214                                                         free(patch_line);
215                                                         break;
216                                                 }
217                                                 free(src_line);
218                                         }
219                                         if (*patch_line == ' ') {
220                                                 fputs(patch_line + 1, dst_stream);
221                                                 dest_cur_line++;
222                                         }
223                                 } else if (*patch_line == '+') {
224                                         fputs(patch_line + 1, dst_stream);
225                                         dest_cur_line++;
226                                 } else {
227                                         break;
228                                 }
229                                 free(patch_line);
230                         }
231                         if (hunk_error) {
232                                 bad_hunk_count++;
233                         }
234                 }
235
236                 /* Cleanup last patched file */
237                 if (copy_trailing_lines_flag) {
238                         copy_lines(src_stream, dst_stream, -1);
239                 }
240                 if (src_stream) {
241                         fclose(src_stream);
242                 }
243                 if (dst_stream) {
244                         fclose(dst_stream);
245                 }
246                 if (bad_hunk_count) {
247                         if (!ret) {
248                                 ret = 1;
249                         }
250                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
251                 } else {
252                         /* It worked, we can remove the backup */
253                         if (backup_filename) {
254                                 unlink(backup_filename);
255                         }
256                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
257                                 /* The new patched file is empty, remove it */
258                                 if (unlink(new_filename) == -1) {
259                                         bb_perror_msg_and_die("cannot remove file %s", new_filename);
260                                 }
261                                 if (unlink(original_filename) == -1) {
262                                         bb_perror_msg_and_die("cannot remove original file %s", new_filename);
263                                 }
264                         }
265                 }
266         }
267
268         /* 0 = SUCCESS
269          * 1 = Some hunks failed
270          * 2 = More serious problems
271          */
272         return(ret);
273 }