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 <bug1@iinet.net.au>
   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 <getopt.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #include "busybox.h"
  27
  28 static unsigned int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
  29 {
  30         unsigned int i = 0;
  31
  32         while (src_stream && (i < lines_count)) {
  33                 char *line;
  34                 line = xmalloc_fgets(src_stream);
  35                 if (line == NULL) {
  36                         break;
  37                 }
  38                 if (fputs(line, dest_stream) == EOF) {
  39                         bb_perror_msg_and_die("error writing to new file");
  40                 }
  41                 free(line);
  42
  43                 i++;
  44         }
  45         return i;
  46 }
  47
  48 /* If patch_level is -1 it will remove all directory names
  49  * char *line must be greater than 4 chars
  50  * returns NULL if the file doesnt exist or error
  51  * returns malloc'ed filename
  52  */
  53
  54 static char *extract_filename(char *line, int patch_level)
  55 {
  56         char *temp, *filename_start_ptr = line + 4;
  57         int i;
  58
  59         /* Terminate string at end of source filename */
  60         temp = strchr(filename_start_ptr, '\t');
  61         if (temp) *temp = 0;
  62
  63         /* skip over (patch_level) number of leading directories */
  64         for (i = 0; i < patch_level; i++) {
  65                 if(!(temp = strchr(filename_start_ptr, '/'))) break;
  66                 filename_start_ptr = temp + 1;
  67         }
  68
  69         return xstrdup(filename_start_ptr);
  70 }
  71
  72 static int file_doesnt_exist(const char *filename)
  73 {
  74         struct stat statbuf;
  75         return stat(filename, &statbuf);
  76 }
  77
  78 int patch_main(int argc, char **argv)
  79 {
  80         int patch_level = -1;
  81         char *patch_line;
  82         int ret;
  83         FILE *patch_file = NULL;
  84
  85         {
  86                 char *p, *i;
  87                 ret = getopt32(argc, argv, "p:i:", &p, &i);
  88                 if (ret & 1)
  89                         patch_level = xatol_range(p, -1, USHRT_MAX);
  90                 if (ret & 2) {
  91                         patch_file = xfopen(i, "r");
  92                 } else {
  93                         patch_file = stdin;
  94                 }
  95                 ret = 0;
  96         }
  97
  98         patch_line = xmalloc_fgets(patch_file);
  99         while (patch_line) {
 100                 FILE *src_stream;
 101                 FILE *dst_stream;
 102                 char *original_filename;
 103                 char *new_filename;
 104                 char *backup_filename;
 105                 unsigned int src_cur_line = 1;
 106                 unsigned int dest_cur_line = 0;
 107                 unsigned int dest_beg_line;
 108                 unsigned int bad_hunk_count = 0;
 109                 unsigned int hunk_count = 0;
 110                 char copy_trailing_lines_flag = 0;
 111
 112                 /* Skip everything upto the "---" marker
 113                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 114                  */
 115                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
 116                         free(patch_line);
 117                         patch_line = xmalloc_fgets(patch_file);
 118                 }
 119                 /* FIXME: patch_line NULL check?? */
 120
 121                 /* Extract the filename used before the patch was generated */
 122                 original_filename = extract_filename(patch_line, patch_level);
 123                 free(patch_line);
 124
 125                 patch_line = xmalloc_fgets(patch_file);
 126                 /* FIXME: NULL check?? */
 127                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 128                         ret = 2;
 129                         bb_error_msg("invalid patch");
 130                         continue;
 131                 }
 132                 new_filename = extract_filename(patch_line, patch_level);
 133                 free(patch_line);
 134
 135                 if (file_doesnt_exist(new_filename)) {
 136                         char *line_ptr;
 137                         /* Create leading directories */
 138                         line_ptr = strrchr(new_filename, '/');
 139                         if (line_ptr) {
 140                                 *line_ptr = '\0';
 141                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 142                                 *line_ptr = '/';
 143                         }
 144                         dst_stream = xfopen(new_filename, "w+");
 145                         backup_filename = NULL;
 146                 } else {
 147                         backup_filename = xmalloc(strlen(new_filename) + 6);
 148                         strcpy(backup_filename, new_filename);
 149                         strcat(backup_filename, ".orig");
 150                         if (rename(new_filename, backup_filename) == -1) {
 151                                 bb_perror_msg_and_die("cannot create file %s",
 152                                                 backup_filename);
 153                         }
 154                         dst_stream = xfopen(new_filename, "w");
 155                 }
 156
 157                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
 158                         src_stream = NULL;
 159                 } else {
 160                         if (strcmp(original_filename, new_filename) == 0) {
 161                                 src_stream = xfopen(backup_filename, "r");
 162                         } else {
 163                                 src_stream = xfopen(original_filename, "r");
 164                         }
 165                 }
 166
 167                 printf("patching file %s\n", new_filename);
 168
 169                 /* Handle each hunk */
 170                 patch_line = xmalloc_fgets(patch_file);
 171                 while (patch_line) {
 172                         unsigned int count;
 173                         unsigned int src_beg_line;
 174                         unsigned int unused;
 175                         unsigned int hunk_offset_start = 0;
 176                         int hunk_error = 0;
 177
 178                         /* This bit should be improved */
 179                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 180                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 181                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 182                                 /* No more hunks for this file */
 183                                 break;
 184                         }
 185                         free(patch_line);
 186                         hunk_count++;
 187
 188                         if (src_beg_line && dest_beg_line) {
 189                                 /* Copy unmodified lines upto start of hunk */
 190                                 /* src_beg_line will be 0 if its a new file */
 191                                 count = src_beg_line - src_cur_line;
 192                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 193                                         bb_error_msg_and_die("bad src file");
 194                                 }
 195                                 src_cur_line += count;
 196                                 dest_cur_line += count;
 197                                 copy_trailing_lines_flag = 1;
 198                         }
 199                         hunk_offset_start = src_cur_line;
 200
 201                         while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
 202                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 203                                         char *src_line = NULL;
 204                                         if (src_stream) {
 205                                                 src_line = xmalloc_fgets(src_stream);
 206                                                 if (!src_line) {
 207                                                         hunk_error++;
 208                                                         break;
 209                                                 } else {
 210                                                         src_cur_line++;
 211                                                 }
 212                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 213                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
 214                                                         hunk_error++;
 215                                                         free(patch_line);
 216                                                         /* Probably need to find next hunk, etc... */
 217                                                         /* but for now we just bail out */
 218                                                         patch_line = NULL;
 219                                                         break;
 220                                                 }
 221                                                 free(src_line);
 222                                         }
 223                                         if (*patch_line == ' ') {
 224                                                 fputs(patch_line + 1, dst_stream);
 225                                                 dest_cur_line++;
 226                                         }
 227                                 } else if (*patch_line == '+') {
 228                                         fputs(patch_line + 1, dst_stream);
 229                                         dest_cur_line++;
 230                                 } else {
 231                                         break;
 232                                 }
 233                                 free(patch_line);
 234                         }
 235                         if (hunk_error) {
 236                                 bad_hunk_count++;
 237                         }
 238                 }
 239
 240                 /* Cleanup last patched file */
 241                 if (copy_trailing_lines_flag) {
 242                         copy_lines(src_stream, dst_stream, -1);
 243                 }
 244                 if (src_stream) {
 245                         fclose(src_stream);
 246                 }
 247                 if (dst_stream) {
 248                         fclose(dst_stream);
 249                 }
 250                 if (bad_hunk_count) {
 251                         if (!ret) {
 252                                 ret = 1;
 253                         }
 254                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 255                 } else {
 256                         /* It worked, we can remove the backup */
 257                         if (backup_filename) {
 258                                 unlink(backup_filename);
 259                         }
 260                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 261                                 /* The new patched file is empty, remove it */
 262                                 if (unlink(new_filename) == -1) {
 263                                         bb_perror_msg_and_die("cannot remove file %s", new_filename);
 264                                 }
 265                                 if (unlink(original_filename) == -1) {
 266                                         bb_perror_msg_and_die("cannot remove original file %s", new_filename);
 267                                 }
 268                         }
 269                 }
 270         }
 271
 272         /* 0 = SUCCESS
 273          * 1 = Some hunks failed
 274          * 2 = More serious problems
 275          */
 276         return ret;
 277 }