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
  78         xfunc_error_retval = 2;
  79         {
  80                 const char *p = "-1";
  81                 const char *i = "-"; /* compat */
  82                 if (getopt32(argv, "p:i:R", &p, &i) & 4)
  83                         plus = '-';
  84                 patch_level = xatoi(p); /* can be negative! */
  85                 patch_file = xfopen_stdin(i);
  86         }
  87
  88         patch_line = xmalloc_fgetline(patch_file);
  89         while (patch_line) {
  90                 FILE *src_stream;
  91                 FILE *dst_stream;
  92                 //char *old_filename;
  93                 char *new_filename;
  94                 char *backup_filename;
  95                 unsigned src_cur_line = 1;
  96                 unsigned dst_cur_line = 0;
  97                 unsigned dst_beg_line;
  98                 unsigned bad_hunk_count = 0;
  99                 unsigned hunk_count = 0;
 100                 smallint copy_trailing_lines_flag = 0;
 101
 102                 /* Skip everything upto the "---" marker
 103                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 104                  */
 105                 do {
 106                         /* Extract the filename used before the patch was generated */
 107                         new_filename = extract_filename(patch_line, patch_level, "--- ");
 108                         // was old_filename above
 109                         patch_line = xmalloc_fgetline(patch_file);
 110                         if (!patch_line) goto quit;
 111                 } while (!new_filename);
 112                 free(new_filename); // "source" filename is irrelevant
 113
 114                 new_filename = extract_filename(patch_line, patch_level, "+++ ");
 115                 if (!new_filename) {
 116                         bb_error_msg_and_die("invalid patch");
 117                 }
 118
 119                 /* Get access rights from the file to be patched */
 120                 if (stat(new_filename, &saved_stat) != 0) {
 121                         char *slash = strrchr(new_filename, '/');
 122                         if (slash) {
 123                                 /* Create leading directories */
 124                                 *slash = '\0';
 125                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 126                                 *slash = '/';
 127                         }
 128                         backup_filename = NULL;
 129                         src_stream = NULL;
 130                         saved_stat.st_mode = 0644;
 131                 } else {
 132                         backup_filename = xasprintf("%s.orig", new_filename);
 133                         xrename(new_filename, backup_filename);
 134                         src_stream = xfopen_for_read(backup_filename);
 135                 }
 136                 dst_stream = xfopen_for_write(new_filename);
 137                 fchmod(fileno(dst_stream), saved_stat.st_mode);
 138
 139                 printf("patching file %s\n", new_filename);
 140
 141                 /* Handle all hunks for this file */
 142                 patch_line = xmalloc_fgets(patch_file);
 143                 while (patch_line) {
 144                         unsigned count;
 145                         unsigned src_beg_line;
 146                         unsigned hunk_offset_start;
 147                         unsigned src_last_line = 1;
 148                         unsigned dst_last_line = 1;
 149
 150                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
 151                          && (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
 152                         ) {
 153                                 /* No more hunks for this file */
 154                                 break;
 155                         }
 156                         if (plus != '+') {
 157                                 /* reverse patch */
 158                                 unsigned tmp = src_last_line;
 159                                 src_last_line = dst_last_line;
 160                                 dst_last_line = tmp;
 161                                 tmp = src_beg_line;
 162                                 src_beg_line = dst_beg_line;
 163                                 dst_beg_line = tmp;
 164                         }
 165                         hunk_count++;
 166
 167                         if (src_beg_line && dst_beg_line) {
 168                                 /* Copy unmodified lines upto start of hunk */
 169                                 /* src_beg_line will be 0 if it's a new file */
 170                                 count = src_beg_line - src_cur_line;
 171                                 if (copy_lines(src_stream, dst_stream, count)) {
 172                                         bb_error_msg_and_die("bad src file");
 173                                 }
 174                                 src_cur_line += count;
 175                                 dst_cur_line += count;
 176                                 copy_trailing_lines_flag = 1;
 177                         }
 178                         src_last_line += hunk_offset_start = src_cur_line;
 179                         dst_last_line += dst_cur_line;
 180
 181                         while (1) {
 182                                 free(patch_line);
 183                                 patch_line = xmalloc_fgets(patch_file);
 184                                 if (patch_line == NULL)
 185                                         break; /* EOF */
 186                                 if ((*patch_line != '-') && (*patch_line != '+')
 187                                  && (*patch_line != ' ')
 188                                 ) {
 189                                         break; /* End of hunk */
 190                                 }
 191                                 if (*patch_line != plus) { /* '-' or ' ' */
 192                                         char *src_line = NULL;
 193                                         if (src_cur_line == src_last_line)
 194                                                 break;
 195                                         if (src_stream) {
 196                                                 src_line = xmalloc_fgets(src_stream);
 197                                                 if (src_line) {
 198                                                         int diff = strcmp(src_line, patch_line + 1);
 199                                                         src_cur_line++;
 200                                                         free(src_line);
 201                                                         if (diff)
 202                                                                 src_line = NULL;
 203                                                 }
 204                                         }
 205                                         if (!src_line) {
 206                                                 bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
 207                                                 bad_hunk_count++;
 208                                                 break;
 209                                         }
 210                                         if (*patch_line != ' ') { /* '-' */
 211                                                 continue;
 212                                         }
 213                                 }
 214                                 if (dst_cur_line == dst_last_line)
 215                                         break;
 216                                 fputs(patch_line + 1, dst_stream);
 217                                 dst_cur_line++;
 218                         } /* end of while loop handling one hunk */
 219                 } /* end of while loop handling one file */
 220
 221                 /* Cleanup last patched file */
 222                 if (copy_trailing_lines_flag) {
 223                         copy_lines(src_stream, dst_stream, (unsigned)(-1));
 224                 }
 225                 if (src_stream) {
 226                         fclose(src_stream);
 227                 }
 228                 fclose(dst_stream);
 229                 if (bad_hunk_count) {
 230                         ret = 1;
 231                         bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
 232                 } else {
 233                         /* It worked, we can remove the backup */
 234                         if (backup_filename) {
 235                                 unlink(backup_filename);
 236                         }
 237                         if ((dst_cur_line == 0) || (dst_beg_line == 0)) {
 238                                 /* The new patched file is empty, remove it */
 239                                 xunlink(new_filename);
 240                                 // /* old_filename and new_filename may be the same file */
 241                                 // unlink(old_filename);
 242                         }
 243                 }
 244                 free(backup_filename);
 245                 //free(old_filename);
 246                 free(new_filename);
 247         } /* end of "while there are patch lines" */
 248  quit:
 249         /* 0 = SUCCESS
 250          * 1 = Some hunks failed
 251          * 2 = More serious problems (exited earlier)
 252          */
 253         return ret;
 254 }