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 *dest_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, dest_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_and_free_line(char *line, int patch_level)
  48 {
  49         char *temp, *filename_start_ptr = line + 4;
  50
  51         /* Terminate string at end of source filename */
  52         temp = strchrnul(filename_start_ptr, '\t');
  53         *temp = '\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
  63         temp = xstrdup(filename_start_ptr);
  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 ATTRIBUTE_UNUSED, 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
  77         xfunc_error_retval = 2;
  78         {
  79                 const char *p = "-1";
  80                 const char *i = "-"; /* compat */
  81                 getopt32(argv, "p:i:", &p, &i);
  82                 patch_level = xatoi(p); /* can be negative! */
  83                 patch_file = xfopen_stdin(i);
  84         }
  85
  86         patch_line = xmalloc_getline(patch_file);
  87         while (patch_line) {
  88                 FILE *src_stream;
  89                 FILE *dst_stream;
  90                 char *original_filename;
  91                 char *new_filename;
  92                 char *backup_filename;
  93                 unsigned src_cur_line = 1;
  94                 unsigned dest_cur_line = 0;
  95                 unsigned dest_beg_line;
  96                 unsigned bad_hunk_count = 0;
  97                 unsigned hunk_count = 0;
  98                 smallint copy_trailing_lines_flag = 0;
  99
 100                 /* Skip everything upto the "---" marker
 101                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 102                  */
 103                 while (strncmp(patch_line, "--- ", 4) != 0) {
 104                         free(patch_line);
 105                         patch_line = xmalloc_getline(patch_file);
 106                         if (!patch_line)
 107                                 bb_error_msg_and_die("invalid patch");
 108                 }
 109
 110                 /* Extract the filename used before the patch was generated */
 111                 original_filename = extract_filename_and_free_line(patch_line, patch_level);
 112
 113                 patch_line = xmalloc_getline(patch_file);
 114                 if (!patch_line || strncmp(patch_line, "+++ ", 4) != 0)
 115                         bb_error_msg_and_die("invalid patch");
 116                 new_filename = extract_filename_and_free_line(patch_line, patch_level);
 117
 118                 /* Get access rights from the file to be patched, -1 file does not exist */
 119                 if (stat(new_filename, &saved_stat) != 0) {
 120                         char *line_ptr;
 121                         /* Create leading directories */
 122                         line_ptr = strrchr(new_filename, '/');
 123                         if (line_ptr) {
 124                                 *line_ptr = '\0';
 125                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 126                                 *line_ptr = '/';
 127                         }
 128                         backup_filename = NULL;
 129                         saved_stat.st_mode = 0644;
 130                 } else {
 131                         backup_filename = xasprintf("%s.orig", new_filename);
 132                         xrename(new_filename, backup_filename);
 133                 }
 134                 dst_stream = xfopen(new_filename, "w");
 135                 fchmod(fileno(dst_stream), saved_stat.st_mode);
 136                 src_stream = NULL;
 137
 138                 if (backup_filename && !stat(original_filename, &saved_stat)) {
 139                         src_stream = xfopen((strcmp(original_filename, new_filename)) ?
 140                                                             original_filename : backup_filename, "r");
 141                 }
 142
 143                 printf("patching file %s\n", new_filename);
 144
 145                 /* Handle all hunks for this file */
 146                 patch_line = xmalloc_fgets(patch_file);
 147                 while (patch_line) {
 148                         unsigned count;
 149                         unsigned src_beg_line;
 150                         unsigned unused;
 151                         unsigned hunk_offset_start = 0;
 152                         smallint hunk_error = 0;
 153
 154                         /* This bit should be improved */
 155                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4)
 156                          && (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3)
 157                          && (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)
 158                         ) {
 159                                 /* No more hunks for this file */
 160                                 break;
 161                         }
 162                         hunk_count++;
 163
 164                         if (src_beg_line && dest_beg_line) {
 165                                 /* Copy unmodified lines upto start of hunk */
 166                                 /* src_beg_line will be 0 if it's a new file */
 167                                 count = src_beg_line - src_cur_line;
 168                                 if (copy_lines(src_stream, dst_stream, count)) {
 169                                         bb_error_msg_and_die("bad src file");
 170                                 }
 171                                 src_cur_line += count;
 172                                 dest_cur_line += count;
 173                                 copy_trailing_lines_flag = 1;
 174                         }
 175                         hunk_offset_start = src_cur_line;
 176
 177                         while (1) {
 178                                 free(patch_line);
 179                                 patch_line = xmalloc_fgets(patch_file);
 180                                 if (patch_line == NULL) break;
 181                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 182                                         char *src_line = NULL;
 183                                         if (src_stream) {
 184                                                 src_line = xmalloc_fgets(src_stream);
 185                                                 if (src_line) {
 186                                                         int diff = strcmp(src_line, patch_line + 1);
 187                                                         src_cur_line++;
 188                                                         free(src_line);
 189                                                         if (diff) src_line = NULL;
 190                                                 }
 191                                                 if (!src_line) {
 192                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
 193                                                         hunk_error = 1;
 194                                                         break;
 195                                                 }
 196                                         }
 197                                         if (*patch_line == ' ') {
 198                                                 fputs(patch_line + 1, dst_stream);
 199                                                 dest_cur_line++;
 200                                         }
 201                                 } else if (*patch_line == '+') {
 202                                         fputs(patch_line + 1, dst_stream);
 203                                         dest_cur_line++;
 204                                 } else {
 205                                         break;
 206                                 }
 207                         } /* end of while loop handling one hunk */
 208                         if (hunk_error) {
 209                                 bad_hunk_count++;
 210                         }
 211                 } /* end of while loop handling one file */
 212
 213                 /* Cleanup last patched file */
 214                 if (copy_trailing_lines_flag) {
 215                         copy_lines(src_stream, dst_stream, (unsigned)(-1));
 216                 }
 217                 if (src_stream) {
 218                         fclose(src_stream);
 219                 }
 220                 if (dst_stream) {
 221                         fclose(dst_stream);
 222                 }
 223                 if (bad_hunk_count) {
 224                         ret = 1;
 225                         bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
 226                 } else {
 227                         /* It worked, we can remove the backup */
 228                         if (backup_filename) {
 229                                 unlink(backup_filename);
 230                                 free(backup_filename);
 231                         }
 232                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 233                                 /* The new patched file is empty, remove it */
 234                                 xunlink(new_filename);
 235                                 if (strcmp(new_filename, original_filename) != 0)
 236                                         xunlink(original_filename);
 237                         }
 238                 }
 239         } /* end of "while there are patch lines" */
 240
 241         /* 0 = SUCCESS
 242          * 1 = Some hunks failed
 243          * 2 = More serious problems (exited earlier)
 244          */
 245         return ret;
 246 }