git.maemo.org Git - busybox4maemo/blob - 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
   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 patch (not just one hunk) will fail.
  19  *   - Reject file isnt saved
  20  */
  21
  22 #include <getopt.h>
  23
  24 #include "libbb.h"
  25
  26 static unsigned int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
  27 {
  28         unsigned int i = 0;
  29
  30         while (src_stream && (i < lines_count)) {
  31                 char *line;
  32                 line = xmalloc_fgets(src_stream);
  33                 if (line == NULL) {
  34                         break;
  35                 }
  36                 if (fputs(line, dest_stream) == EOF) {
  37                         bb_perror_msg_and_die("error writing to new file");
  38                 }
  39                 free(line);
  40
  41                 i++;
  42         }
  43         return i;
  44 }
  45
  46 /* If patch_level is -1 it will remove all directory names
  47  * char *line must be greater than 4 chars
  48  * returns NULL if the file doesnt exist or error
  49  * returns malloc'ed filename
  50  */
  51
  52 static char *extract_filename(char *line, int patch_level)
  53 {
  54         char *temp, *filename_start_ptr = line + 4;
  55         int i;
  56
  57         /* Terminate string at end of source filename */
  58         temp = strchrnul(filename_start_ptr, '\t');
  59         *temp = '\0';
  60
  61         /* Skip over (patch_level) number of leading directories */
  62         if (patch_level == -1)
  63                 patch_level = INT_MAX;
  64         for (i = 0; i < patch_level; i++) {
  65                 temp = strchr(filename_start_ptr, '/');
  66                 if (!temp)
  67                         break;
  68                 filename_start_ptr = temp + 1;
  69         }
  70
  71         return xstrdup(filename_start_ptr);
  72 }
  73
  74 int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  75 int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
  76 {
  77         int patch_level = -1;
  78         char *patch_line;
  79         int ret;
  80         FILE *patch_file = NULL;
  81         struct stat saved_stat;
  82
  83         {
  84                 char *p, *i;
  85                 ret = getopt32(argv, "p:i:", &p, &i);
  86                 if (ret & 1)
  87                         patch_level = xatol_range(p, -1, USHRT_MAX);
  88                 if (ret & 2) {
  89                         patch_file = xfopen(i, "r");
  90                 } else {
  91                         patch_file = stdin;
  92                 }
  93                 ret = 0;
  94         }
  95
  96         patch_line = xmalloc_getline(patch_file);
  97         while (patch_line) {
  98                 FILE *src_stream;
  99                 FILE *dst_stream;
 100                 char *original_filename;
 101                 char *new_filename;
 102                 char *backup_filename;
 103                 unsigned int src_cur_line = 1;
 104                 unsigned int dest_cur_line = 0;
 105                 unsigned int dest_beg_line;
 106                 unsigned int bad_hunk_count = 0;
 107                 unsigned int hunk_count = 0;
 108                 char copy_trailing_lines_flag = 0;
 109
 110                 /* Skip everything upto the "---" marker
 111                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 112                  */
 113                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
 114                         free(patch_line);
 115                         patch_line = xmalloc_getline(patch_file);
 116                 }
 117                 /* FIXME: patch_line NULL check?? */
 118
 119                 /* Extract the filename used before the patch was generated */
 120                 original_filename = extract_filename(patch_line, patch_level);
 121                 free(patch_line);
 122
 123                 patch_line = xmalloc_getline(patch_file);
 124                 /* FIXME: NULL check?? */
 125                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 126                         ret = 2;
 127                         bb_error_msg("invalid patch");
 128                         continue;
 129                 }
 130                 new_filename = extract_filename(patch_line, patch_level);
 131                 free(patch_line);
 132
 133                 /* Get access rights from the file to be patched, -1 file does not exist */
 134                 if (stat(new_filename, &saved_stat)) {
 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                         xrename(new_filename, backup_filename);
 150                         dst_stream = xfopen(new_filename, "w");
 151                         fchmod(fileno(dst_stream), saved_stat.st_mode);
 152                 }
 153
 154                 if ((backup_filename == NULL) || stat(original_filename, &saved_stat)) {
 155                         src_stream = NULL;
 156                 } else {
 157                         if (strcmp(original_filename, new_filename) == 0) {
 158                                 src_stream = xfopen(backup_filename, "r");
 159                         } else {
 160                                 src_stream = xfopen(original_filename, "r");
 161                         }
 162                 }
 163
 164                 printf("patching file %s\n", new_filename);
 165
 166                 /* Handle each hunk */
 167                 patch_line = xmalloc_fgets(patch_file);
 168                 while (patch_line) {
 169                         unsigned int count;
 170                         unsigned int src_beg_line;
 171                         unsigned int unused;
 172                         unsigned int hunk_offset_start = 0;
 173                         int hunk_error = 0;
 174
 175                         /* This bit should be improved */
 176                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 177                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 178                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 179                                 /* No more hunks for this file */
 180                                 break;
 181                         }
 182                         free(patch_line);
 183                         hunk_count++;
 184
 185                         if (src_beg_line && dest_beg_line) {
 186                                 /* Copy unmodified lines upto start of hunk */
 187                                 /* src_beg_line will be 0 if its a new file */
 188                                 count = src_beg_line - src_cur_line;
 189                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 190                                         bb_error_msg_and_die("bad src file");
 191                                 }
 192                                 src_cur_line += count;
 193                                 dest_cur_line += count;
 194                                 copy_trailing_lines_flag = 1;
 195                         }
 196                         hunk_offset_start = src_cur_line;
 197
 198                         while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
 199                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 200                                         char *src_line = NULL;
 201                                         if (src_stream) {
 202                                                 src_line = xmalloc_fgets(src_stream);
 203                                                 if (!src_line) {
 204                                                         hunk_error++;
 205                                                         break;
 206                                                 } else {
 207                                                         src_cur_line++;
 208                                                 }
 209                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 210                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
 211                                                         hunk_error++;
 212                                                         free(patch_line);
 213                                                         /* Probably need to find next hunk, etc... */
 214                                                         /* but for now we just bail out */
 215                                                         patch_line = NULL;
 216                                                         break;
 217                                                 }
 218                                                 free(src_line);
 219                                         }
 220                                         if (*patch_line == ' ') {
 221                                                 fputs(patch_line + 1, dst_stream);
 222                                                 dest_cur_line++;
 223                                         }
 224                                 } else if (*patch_line == '+') {
 225                                         fputs(patch_line + 1, dst_stream);
 226                                         dest_cur_line++;
 227                                 } else {
 228                                         break;
 229                                 }
 230                                 free(patch_line);
 231                         }
 232                         if (hunk_error) {
 233                                 bad_hunk_count++;
 234                         }
 235                 }
 236
 237                 /* Cleanup last patched file */
 238                 if (copy_trailing_lines_flag) {
 239                         copy_lines(src_stream, dst_stream, -1);
 240                 }
 241                 if (src_stream) {
 242                         fclose(src_stream);
 243                 }
 244                 if (dst_stream) {
 245                         fclose(dst_stream);
 246                 }
 247                 if (bad_hunk_count) {
 248                         if (!ret) {
 249                                 ret = 1;
 250                         }
 251                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 252                 } else {
 253                         /* It worked, we can remove the backup */
 254                         if (backup_filename) {
 255                                 unlink(backup_filename);
 256                         }
 257                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 258                                 /* The new patched file is empty, remove it */
 259                                 xunlink(new_filename);
 260                                 if (strcmp(new_filename, original_filename) != 0)
 261                                         xunlink(original_filename);
 262                         }
 263                 }
 264         }
 265
 266         /* 0 = SUCCESS
 267          * 1 = Some hunks failed
 268          * 2 = More serious problems
 269          */
 270         return ret;
 271 }