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         };
  82
  83         xfunc_error_retval = 2;
  84         {
  85                 const char *p = "-1";
  86                 const char *i = "-"; /* compat */
  87                 opt = getopt32(argv, "p:i:RN", &p, &i);
  88                 if (opt & OPT_R)
  89                         plus = '-';
  90                 patch_level = xatoi(p); /* can be negative! */
  91                 patch_file = xfopen_stdin(i);
  92         }
  93
  94         patch_line = xmalloc_fgetline(patch_file);
  95         while (patch_line) {
  96                 FILE *src_stream;
  97                 FILE *dst_stream;
  98                 //char *old_filename;
  99                 char *new_filename;
 100                 char *backup_filename;
 101                 unsigned src_cur_line = 1;
 102                 unsigned dst_cur_line = 0;
 103                 unsigned dst_beg_line;
 104                 unsigned bad_hunk_count = 0;
 105                 unsigned hunk_count = 0;
 106                 smallint copy_trailing_lines_flag = 0;
 107
 108                 /* Skip everything upto the "---" marker
 109                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 110                  */
 111                 do {
 112                         /* Extract the filename used before the patch was generated */
 113                         new_filename = extract_filename(patch_line, patch_level, "--- ");
 114                         // was old_filename above
 115                         patch_line = xmalloc_fgetline(patch_file);
 116                         if (!patch_line) goto quit;
 117                 } while (!new_filename);
 118                 free(new_filename); // "source" filename is irrelevant
 119
 120                 new_filename = extract_filename(patch_line, patch_level, "+++ ");
 121                 if (!new_filename) {
 122                         bb_error_msg_and_die("invalid patch");
 123                 }
 124
 125                 /* Get access rights from the file to be patched */
 126                 if (stat(new_filename, &saved_stat) != 0) {
 127                         char *slash = strrchr(new_filename, '/');
 128                         if (slash) {
 129                                 /* Create leading directories */
 130                                 *slash = '\0';
 131                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 132                                 *slash = '/';
 133                         }
 134                         backup_filename = NULL;
 135                         src_stream = NULL;
 136                         saved_stat.st_mode = 0644;
 137                 } else {
 138                         backup_filename = xasprintf("%s.orig", new_filename);
 139                         xrename(new_filename, backup_filename);
 140                         src_stream = xfopen_for_read(backup_filename);
 141                 }
 142                 dst_stream = xfopen_for_write(new_filename);
 143                 fchmod(fileno(dst_stream), saved_stat.st_mode);
 144
 145                 printf("patching file %s\n", new_filename);
 146
 147                 /* Handle all hunks for this file */
 148                 patch_line = xmalloc_fgets(patch_file);
 149                 while (patch_line) {
 150                         unsigned count;
 151                         unsigned src_beg_line;
 152                         unsigned hunk_offset_start;
 153                         unsigned src_last_line = 1;
 154                         unsigned dst_last_line = 1;
 155
 156                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
 157                          && (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
 158                         ) {
 159                                 /* No more hunks for this file */
 160                                 break;
 161                         }
 162                         if (plus != '+') {
 163                                 /* reverse patch */
 164                                 unsigned tmp = src_last_line;
 165                                 src_last_line = dst_last_line;
 166                                 dst_last_line = tmp;
 167                                 tmp = src_beg_line;
 168                                 src_beg_line = dst_beg_line;
 169                                 dst_beg_line = tmp;
 170                         }
 171                         hunk_count++;
 172
 173                         if (src_beg_line && dst_beg_line) {
 174                                 /* Copy unmodified lines upto start of hunk */
 175                                 /* src_beg_line will be 0 if it's a new file */
 176                                 count = src_beg_line - src_cur_line;
 177                                 if (copy_lines(src_stream, dst_stream, count)) {
 178                                         bb_error_msg_and_die("bad src file");
 179                                 }
 180                                 src_cur_line += count;
 181                                 dst_cur_line += count;
 182                                 copy_trailing_lines_flag = 1;
 183                         }
 184                         src_last_line += hunk_offset_start = src_cur_line;
 185                         dst_last_line += dst_cur_line;
 186
 187                         while (1) {
 188                                 free(patch_line);
 189                                 patch_line = xmalloc_fgets(patch_file);
 190                                 if (patch_line == NULL)
 191                                         break; /* EOF */
 192                                 if ((*patch_line != '-') && (*patch_line != '+')
 193                                  && (*patch_line != ' ')
 194                                 ) {
 195                                         break; /* End of hunk */
 196                                 }
 197                                 if (*patch_line != plus) { /* '-' or ' ' */
 198                                         char *src_line = NULL;
 199                                         if (src_cur_line == src_last_line)
 200                                                 break;
 201                                         if (src_stream) {
 202                                                 src_line = xmalloc_fgets(src_stream);
 203                                                 if (src_line) {
 204                                                         int diff = strcmp(src_line, patch_line + 1);
 205                                                         src_cur_line++;
 206                                                         free(src_line);
 207                                                         if (diff)
 208                                                                 src_line = NULL;
 209                                                 }
 210                                         }
 211                                         /* Do not patch an already patched hunk with -N */
 212                                         if (src_line == 0 && (opt & OPT_N)) {
 213                                                 continue;
 214                                         }
 215                                         if (!src_line) {
 216                                                 bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
 217                                                 bad_hunk_count++;
 218                                                 break;
 219                                         }
 220                                         if (*patch_line != ' ') { /* '-' */
 221                                                 continue;
 222                                         }
 223                                 }
 224                                 if (dst_cur_line == dst_last_line)
 225                                         break;
 226                                 fputs(patch_line + 1, dst_stream);
 227                                 dst_cur_line++;
 228                         } /* end of while loop handling one hunk */
 229                 } /* end of while loop handling one file */
 230
 231                 /* Cleanup last patched file */
 232                 if (copy_trailing_lines_flag) {
 233                         copy_lines(src_stream, dst_stream, (unsigned)(-1));
 234                 }
 235                 if (src_stream) {
 236                         fclose(src_stream);
 237                 }
 238                 fclose(dst_stream);
 239                 if (bad_hunk_count) {
 240                         ret = 1;
 241                         bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
 242                 } else {
 243                         /* It worked, we can remove the backup */
 244                         if (backup_filename) {
 245                                 unlink(backup_filename);
 246                         }
 247                         if ((dst_cur_line == 0) || (dst_beg_line == 0)) {
 248                                 /* The new patched file is empty, remove it */
 249                                 xunlink(new_filename);
 250                                 // /* old_filename and new_filename may be the same file */
 251                                 // unlink(old_filename);
 252                         }
 253                 }
 254                 free(backup_filename);
 255                 //free(old_filename);
 256                 free(new_filename);
 257         } /* end of "while there are patch lines" */
 258  quit:
 259         /* 0 = SUCCESS
 260          * 1 = Some hunks failed
 261          * 2 = More serious problems (exited earlier)
 262          */
 263         return ret;
 264 }