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 "libbb.h"
  23
  24 static unsigned copy_lines(FILE *src_stream, FILE *dst_stream, unsigned lines_count)
  25 {
  26         while (src_stream && lines_count) {
  27                 char *line;
  28                 line = xmalloc_fgets(src_stream);
  29                 if (line == NULL) {
  30                         break;
  31                 }
  32                 if (fputs(line, dst_stream) == EOF) {
  33                         bb_perror_msg_and_die("error writing to new file");
  34                 }
  35                 free(line);
  36                 lines_count--;
  37         }
  38         return lines_count;
  39 }
  40
  41 /* If patch_level is -1 it will remove all directory names
  42  * char *line must be greater than 4 chars
  43  * returns NULL if the file doesnt exist or error
  44  * returns malloc'ed filename
  45  * NB: frees 1st argument!
  46  */
  47 static char *extract_filename(char *line, int patch_level, const char *pat)
  48 {
  49         char *temp = NULL, *filename_start_ptr = line + 4;
  50
  51         if (strncmp(line, pat, 4) == 0) {
  52                 /* Terminate string at end of source filename */
  53                 line[strcspn(line, "\t\n\r")] = '\0';
  54
  55                 /* Skip over (patch_level) number of leading directories */
  56                 while (patch_level--) {
  57                         temp = strchr(filename_start_ptr, '/');
  58                         if (!temp)
  59                                 break;
  60                         filename_start_ptr = temp + 1;
  61                 }
  62                 temp = xstrdup(filename_start_ptr);
  63         }
  64         free(line);
  65         return temp;
  66 }
  67
  68 int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  69 int patch_main(int argc UNUSED_PARAM, char **argv)
  70 {
  71         struct stat saved_stat;
  72         char *patch_line;
  73         FILE *patch_file;
  74         int patch_level;
  75         int ret = 0;
  76         char plus = '+';
  77         unsigned opt;
  78         enum {
  79                 OPT_R = (1 << 2),
  80                 OPT_N = (1 << 3),
  81                 OPT_dry_run = (1 << 4) * ENABLE_LONG_OPTS,
  82         };
  83
  84         xfunc_error_retval = 2;
  85         {
  86                 const char *p = "-1";
  87                 const char *i = "-"; /* compat */
  88 #if ENABLE_LONG_OPTS
  89                 static const char patch_longopts[] ALIGN1 =
  90                         "strip\0"   Required_argument "p"
  91                         "input\0"   Required_argument "i"
  92                         "reverse\0" No_argument       "R"
  93                         "forward\0" No_argument       "N"
  94                         "dry-run\0" No_argument       "\xff"
  95                         ;
  96                 applet_long_options = patch_longopts;
  97 #endif
  98                 opt = getopt32(argv, "p:i:RN", &p, &i);
  99                 if (opt & OPT_R)
 100                         plus = '-';
 101                 patch_level = xatoi(p); /* can be negative! */
 102                 patch_file = xfopen_stdin(i);
 103         }
 104
 105         patch_line = xmalloc_fgetline(patch_file);
 106         while (patch_line) {
 107                 FILE *src_stream;
 108                 FILE *dst_stream;
 109                 //char *old_filename;
 110                 char *new_filename;
 111                 char *backup_filename = NULL;
 112                 unsigned src_cur_line = 1;
 113                 unsigned dst_cur_line = 0;
 114                 unsigned dst_beg_line;
 115                 unsigned bad_hunk_count = 0;
 116                 unsigned hunk_count = 0;
 117                 smallint copy_trailing_lines_flag = 0;
 118
 119                 /* Skip everything upto the "---" marker
 120                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 121                  */
 122                 do {
 123                         /* Extract the filename used before the patch was generated */
 124                         new_filename = extract_filename(patch_line, patch_level, "--- ");
 125                         // was old_filename above
 126                         patch_line = xmalloc_fgetline(patch_file);
 127                         if (!patch_line) goto quit;
 128                 } while (!new_filename);
 129                 free(new_filename); // "source" filename is irrelevant
 130
 131                 new_filename = extract_filename(patch_line, patch_level, "+++ ");
 132                 if (!new_filename) {
 133                         bb_error_msg_and_die("invalid patch");
 134                 }
 135
 136                 /* Get access rights from the file to be patched */
 137                 if (stat(new_filename, &saved_stat) != 0) {
 138                         char *slash = strrchr(new_filename, '/');
 139                         if (slash) {
 140                                 /* Create leading directories */
 141                                 *slash = '\0';
 142                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 143                                 *slash = '/';
 144                         }
 145                         src_stream = NULL;
 146                         saved_stat.st_mode = 0644;
 147                 } else if (!(opt & OPT_dry_run)) {
 148                         backup_filename = xasprintf("%s.orig", new_filename);
 149                         xrename(new_filename, backup_filename);
 150                         src_stream = xfopen_for_read(backup_filename);
 151                 } else
 152                         src_stream = xfopen_for_read(new_filename);
 153
 154                 if (opt & OPT_dry_run) {
 155                         dst_stream = xfopen_for_write("/dev/null");
 156                 } else {
 157                         dst_stream = xfopen_for_write(new_filename);
 158                         fchmod(fileno(dst_stream), saved_stat.st_mode);
 159                 }
 160
 161                 printf("patching file %s\n", new_filename);
 162
 163                 /* Handle all hunks for this file */
 164                 patch_line = xmalloc_fgets(patch_file);
 165                 while (patch_line) {
 166                         unsigned count;
 167                         unsigned src_beg_line;
 168                         unsigned hunk_offset_start;
 169                         unsigned src_last_line = 1;
 170                         unsigned dst_last_line = 1;
 171
 172                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
 173                          && (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
 174                         ) {
 175                                 /* No more hunks for this file */
 176                                 break;
 177                         }
 178                         if (plus != '+') {
 179                                 /* reverse patch */
 180                                 unsigned tmp = src_last_line;
 181                                 src_last_line = dst_last_line;
 182                                 dst_last_line = tmp;
 183                                 tmp = src_beg_line;
 184                                 src_beg_line = dst_beg_line;
 185                                 dst_beg_line = tmp;
 186                         }
 187                         hunk_count++;
 188
 189                         if (src_beg_line && dst_beg_line) {
 190                                 /* Copy unmodified lines upto start of hunk */
 191                                 /* src_beg_line will be 0 if it's a new file */
 192                                 count = src_beg_line - src_cur_line;
 193                                 if (copy_lines(src_stream, dst_stream, count)) {
 194                                         bb_error_msg_and_die("bad src file");
 195                                 }
 196                                 src_cur_line += count;
 197                                 dst_cur_line += count;
 198                                 copy_trailing_lines_flag = 1;
 199                         }
 200                         src_last_line += hunk_offset_start = src_cur_line;
 201                         dst_last_line += dst_cur_line;
 202
 203                         while (1) {
 204                                 free(patch_line);
 205                                 patch_line = xmalloc_fgets(patch_file);
 206                                 if (patch_line == NULL)
 207                                         break; /* EOF */
 208                                 if (!*patch_line) {
 209                                         /* whitespace-damaged patch with "" lines */
 210                                         free(patch_line);
 211                                         patch_line = xstrdup(" ");
 212                                 }
 213                                 if ((*patch_line != '-') && (*patch_line != '+')
 214                                  && (*patch_line != ' ')
 215                                 ) {
 216                                         break; /* End of hunk */
 217                                 }
 218                                 if (*patch_line != plus) { /* '-' or ' ' */
 219                                         char *src_line = NULL;
 220                                         if (src_cur_line == src_last_line)
 221                                                 break;
 222                                         if (src_stream) {
 223                                                 src_line = xmalloc_fgets(src_stream);
 224                                                 if (src_line) {
 225                                                         int diff = strcmp(src_line, patch_line + 1);
 226                                                         src_cur_line++;
 227                                                         free(src_line);
 228                                                         if (diff)
 229                                                                 src_line = NULL;
 230                                                 }
 231                                         }
 232                                         /* Do not patch an already patched hunk with -N */
 233                                         if (src_line == 0 && (opt & OPT_N)) {
 234                                                 continue;
 235                                         }
 236                                         if (!src_line) {
 237                                                 bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
 238                                                 bad_hunk_count++;
 239                                                 break;
 240                                         }
 241                                         if (*patch_line != ' ') { /* '-' */
 242                                                 continue;
 243                                         }
 244                                 }
 245                                 if (dst_cur_line == dst_last_line)
 246                                         break;
 247                                 fputs(patch_line + 1, dst_stream);
 248                                 dst_cur_line++;
 249                         } /* end of while loop handling one hunk */
 250                 } /* end of while loop handling one file */
 251
 252                 /* Cleanup last patched file */
 253                 if (copy_trailing_lines_flag) {
 254                         copy_lines(src_stream, dst_stream, (unsigned)(-1));
 255                 }
 256                 if (src_stream) {
 257                         fclose(src_stream);
 258                 }
 259                 fclose(dst_stream);
 260                 if (bad_hunk_count) {
 261                         ret = 1;
 262                         bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
 263                 } else {
 264                         /* It worked, we can remove the backup */
 265                         if (backup_filename) {
 266                                 unlink(backup_filename);
 267                         }
 268                         if (!(opt & OPT_dry_run)
 269                          && ((dst_cur_line == 0) || (dst_beg_line == 0))
 270                         ) {
 271                                 /* The new patched file is empty, remove it */
 272                                 xunlink(new_filename);
 273                                 // /* old_filename and new_filename may be the same file */
 274                                 // unlink(old_filename);
 275                         }
 276                 }
 277                 free(backup_filename);
 278                 //free(old_filename);
 279                 free(new_filename);
 280         } /* end of "while there are patch lines" */
 281  quit:
 282         /* 0 = SUCCESS
 283          * 1 = Some hunks failed
 284          * 2 = More serious problems (exited earlier)
 285          */
 286         return ret;
 287 }