editors/patch_bbox.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 GPLv2 or later, see file LICENSE in this source tree.
   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_f = (1 << 4), ignored */
  82                 /*OPT_E = (1 << 5), ignored, this is the default */
  83                 /*OPT_g = (1 << 6), ignored */
  84                 OPT_dry_run = (1 << 7) * ENABLE_LONG_OPTS,
  85         };
  86
  87         xfunc_error_retval = 2;
  88         {
  89                 const char *p = "-1";
  90                 const char *i = "-"; /* compat */
  91 #if ENABLE_LONG_OPTS
  92                 static const char patch_longopts[] ALIGN1 =
  93                         "strip\0"                 Required_argument "p"
  94                         "input\0"                 Required_argument "i"
  95                         "reverse\0"               No_argument       "R"
  96                         "forward\0"               No_argument       "N"
  97                 /* "Assume user knows what [s]he is doing, do not ask any questions": */
  98                         "force\0"                 No_argument       "f" /*ignored*/
  99 # if ENABLE_DESKTOP
 100                         "remove-empty-files\0"    No_argument       "E" /*ignored*/
 101                 /* "Controls actions when a file is under RCS or SCCS control,
 102                  * and does not exist or is read-only and matches the default version,
 103                  * or when a file is under ClearCase control and does not exist..."
 104                  * IOW: rather obscure option.
 105                  * But Gentoo's portage does use -g0 */
 106                         "get\0"                   Required_argument "g" /*ignored*/
 107 # endif
 108                         "dry-run\0"               No_argument       "\xfd"
 109 # if ENABLE_DESKTOP
 110                         "backup-if-mismatch\0"    No_argument       "\xfe" /*ignored*/
 111                         "no-backup-if-mismatch\0" No_argument       "\xff" /*ignored*/
 112 # endif
 113                         ;
 114                 applet_long_options = patch_longopts;
 115 #endif
 116                 /* -f,-E,-g are ignored */
 117                 opt = getopt32(argv, "p:i:RN""fEg:", &p, &i, NULL);
 118                 if (opt & OPT_R)
 119                         plus = '-';
 120                 patch_level = xatoi(p); /* can be negative! */
 121                 patch_file = xfopen_stdin(i);
 122         }
 123
 124         patch_line = xmalloc_fgetline(patch_file);
 125         while (patch_line) {
 126                 FILE *src_stream;
 127                 FILE *dst_stream;
 128                 //char *old_filename;
 129                 char *new_filename;
 130                 char *backup_filename = NULL;
 131                 unsigned src_cur_line = 1;
 132                 unsigned dst_cur_line = 0;
 133                 unsigned dst_beg_line;
 134                 unsigned bad_hunk_count = 0;
 135                 unsigned hunk_count = 0;
 136                 smallint copy_trailing_lines_flag = 0;
 137
 138                 /* Skip everything upto the "---" marker
 139                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 140                  */
 141                 do {
 142                         /* Extract the filename used before the patch was generated */
 143                         new_filename = extract_filename(patch_line, patch_level, "--- ");
 144                         // was old_filename above
 145                         patch_line = xmalloc_fgetline(patch_file);
 146                         if (!patch_line) goto quit;
 147                 } while (!new_filename);
 148                 free(new_filename); // "source" filename is irrelevant
 149
 150                 new_filename = extract_filename(patch_line, patch_level, "+++ ");
 151                 if (!new_filename) {
 152                         bb_error_msg_and_die("invalid patch");
 153                 }
 154
 155                 /* Get access rights from the file to be patched */
 156                 if (stat(new_filename, &saved_stat) != 0) {
 157                         char *slash = strrchr(new_filename, '/');
 158                         if (slash) {
 159                                 /* Create leading directories */
 160                                 *slash = '\0';
 161                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 162                                 *slash = '/';
 163                         }
 164                         src_stream = NULL;
 165                         saved_stat.st_mode = 0644;
 166                 } else if (!(opt & OPT_dry_run)) {
 167                         backup_filename = xasprintf("%s.orig", new_filename);
 168                         xrename(new_filename, backup_filename);
 169                         src_stream = xfopen_for_read(backup_filename);
 170                 } else
 171                         src_stream = xfopen_for_read(new_filename);
 172
 173                 if (opt & OPT_dry_run) {
 174                         dst_stream = xfopen_for_write("/dev/null");
 175                 } else {
 176                         dst_stream = xfopen_for_write(new_filename);
 177                         fchmod(fileno(dst_stream), saved_stat.st_mode);
 178                 }
 179
 180                 printf("patching file %s\n", new_filename);
 181
 182                 /* Handle all hunks for this file */
 183                 patch_line = xmalloc_fgets(patch_file);
 184                 while (patch_line) {
 185                         unsigned count;
 186                         unsigned src_beg_line;
 187                         unsigned hunk_offset_start;
 188                         unsigned src_last_line = 1;
 189                         unsigned dst_last_line = 1;
 190
 191                         if ((sscanf(patch_line, "@@ -%u,%u +%u,%u", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
 192                          && (sscanf(patch_line, "@@ -%u +%u,%u", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
 193                         ) {
 194                                 /* No more hunks for this file */
 195                                 break;
 196                         }
 197                         if (plus != '+') {
 198                                 /* reverse patch */
 199                                 unsigned tmp = src_last_line;
 200                                 src_last_line = dst_last_line;
 201                                 dst_last_line = tmp;
 202                                 tmp = src_beg_line;
 203                                 src_beg_line = dst_beg_line;
 204                                 dst_beg_line = tmp;
 205                         }
 206                         hunk_count++;
 207
 208                         if (src_beg_line && dst_beg_line) {
 209                                 /* Copy unmodified lines upto start of hunk */
 210                                 /* src_beg_line will be 0 if it's a new file */
 211                                 count = src_beg_line - src_cur_line;
 212                                 if (copy_lines(src_stream, dst_stream, count)) {
 213                                         bb_error_msg_and_die("bad src file");
 214                                 }
 215                                 src_cur_line += count;
 216                                 dst_cur_line += count;
 217                                 copy_trailing_lines_flag = 1;
 218                         }
 219                         src_last_line += hunk_offset_start = src_cur_line;
 220                         dst_last_line += dst_cur_line;
 221
 222                         while (1) {
 223                                 free(patch_line);
 224                                 patch_line = xmalloc_fgets(patch_file);
 225                                 if (patch_line == NULL)
 226                                         break; /* EOF */
 227                                 if (!*patch_line) {
 228                                         /* whitespace-damaged patch with "" lines */
 229                                         free(patch_line);
 230                                         patch_line = xstrdup(" ");
 231                                 }
 232                                 if ((*patch_line != '-') && (*patch_line != '+')
 233                                  && (*patch_line != ' ')
 234                                 ) {
 235                                         break; /* End of hunk */
 236                                 }
 237                                 if (*patch_line != plus) { /* '-' or ' ' */
 238                                         char *src_line = NULL;
 239                                         if (src_cur_line == src_last_line)
 240                                                 break;
 241                                         if (src_stream) {
 242                                                 src_line = xmalloc_fgets(src_stream);
 243                                                 if (src_line) {
 244                                                         int diff = strcmp(src_line, patch_line + 1);
 245                                                         src_cur_line++;
 246                                                         free(src_line);
 247                                                         if (diff)
 248                                                                 src_line = NULL;
 249                                                 }
 250                                         }
 251                                         /* Do not patch an already patched hunk with -N */
 252                                         if (src_line == 0 && (opt & OPT_N)) {
 253                                                 continue;
 254                                         }
 255                                         if (!src_line) {
 256                                                 bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
 257                                                 bad_hunk_count++;
 258                                                 break;
 259                                         }
 260                                         if (*patch_line != ' ') { /* '-' */
 261                                                 continue;
 262                                         }
 263                                 }
 264                                 if (dst_cur_line == dst_last_line)
 265                                         break;
 266                                 fputs(patch_line + 1, dst_stream);
 267                                 dst_cur_line++;
 268                         } /* end of while loop handling one hunk */
 269                 } /* end of while loop handling one file */
 270
 271                 /* Cleanup last patched file */
 272                 if (copy_trailing_lines_flag) {
 273                         copy_lines(src_stream, dst_stream, (unsigned)(-1));
 274                 }
 275                 if (src_stream) {
 276                         fclose(src_stream);
 277                 }
 278                 fclose(dst_stream);
 279                 if (bad_hunk_count) {
 280                         ret = 1;
 281                         bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
 282                 } else {
 283                         /* It worked, we can remove the backup */
 284                         if (backup_filename) {
 285                                 unlink(backup_filename);
 286                         }
 287                         if (!(opt & OPT_dry_run)
 288                          && ((dst_cur_line == 0) || (dst_beg_line == 0))
 289                         ) {
 290                                 /* The new patched file is empty, remove it */
 291                                 xunlink(new_filename);
 292                                 // /* old_filename and new_filename may be the same file */
 293                                 // unlink(old_filename);
 294                         }
 295                 }
 296                 free(backup_filename);
 297                 //free(old_filename);
 298                 free(new_filename);
 299         } /* end of "while there are patch lines" */
 300  quit:
 301         /* 0 = SUCCESS
 302          * 1 = Some hunks failed
 303          * 2 = More serious problems (exited earlier)
 304          */
 305         return ret;
 306 }