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 the hunk will fail.
  19  *   - Reject file isnt saved
  20  *   -
  21  */
  22
  23 #include <getopt.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include "busybox.h"
  28
  29 static unsigned int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
  30 {
  31         unsigned int i = 0;
  32
  33         while (src_stream && (i < lines_count)) {
  34                 char *line;
  35                 line = xmalloc_fgets(src_stream);
  36                 if (line == NULL) {
  37                         break;
  38                 }
  39                 if (fputs(line, dest_stream) == EOF) {
  40                         bb_perror_msg_and_die("error writing to new file");
  41                 }
  42                 free(line);
  43
  44                 i++;
  45         }
  46         return(i);
  47 }
  48
  49 /* If patch_level is -1 it will remove all directory names
  50  * char *line must be greater than 4 chars
  51  * returns NULL if the file doesnt exist or error
  52  * returns malloc'ed filename
  53  */
  54
  55 static char *extract_filename(char *line, int patch_level)
  56 {
  57         char *temp, *filename_start_ptr = line + 4;
  58         int i;
  59
  60         /* Terminate string at end of source filename */
  61         temp = strchr(filename_start_ptr, '\t');
  62         if (temp) *temp = 0;
  63
  64         /* skip over (patch_level) number of leading directories */
  65         for (i = 0; i < patch_level; i++) {
  66                 if(!(temp = strchr(filename_start_ptr, '/'))) break;
  67                 filename_start_ptr = temp + 1;
  68         }
  69
  70         return(xstrdup(filename_start_ptr));
  71 }
  72
  73 static int file_doesnt_exist(const char *filename)
  74 {
  75         struct stat statbuf;
  76         return(stat(filename, &statbuf));
  77 }
  78
  79 int patch_main(int argc, char **argv)
  80 {
  81         int patch_level = -1;
  82         char *patch_line;
  83         int ret;
  84         FILE *patch_file = NULL;
  85
  86         {
  87                 char *p, *i;
  88                 ret = getopt32(argc, argv, "p:i:", &p, &i);
  89                 if (ret & 1)
  90                         patch_level = xatol_range(p, -1, USHRT_MAX);
  91                 if (ret & 2) {
  92                         patch_file = xfopen(i, "r");
  93                 } else {
  94                         patch_file = stdin;
  95                 }
  96                 ret = 0;
  97         }
  98
  99         patch_line = xmalloc_fgets(patch_file);
 100         while (patch_line) {
 101                 FILE *src_stream;
 102                 FILE *dst_stream;
 103                 char *original_filename;
 104                 char *new_filename;
 105                 char *backup_filename;
 106                 unsigned int src_cur_line = 1;
 107                 unsigned int dest_cur_line = 0;
 108                 unsigned int dest_beg_line;
 109                 unsigned int bad_hunk_count = 0;
 110                 unsigned int hunk_count = 0;
 111                 char copy_trailing_lines_flag = 0;
 112
 113                 /* Skip everything upto the "---" marker
 114                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 115                  */
 116                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
 117                         free(patch_line);
 118                         patch_line = xmalloc_fgets(patch_file);
 119                 }
 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                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 127                         ret = 2;
 128                         bb_error_msg("invalid patch");
 129                         continue;
 130                 }
 131                 new_filename = extract_filename(patch_line, patch_level);
 132                 free(patch_line);
 133
 134                 if (file_doesnt_exist(new_filename)) {
 135                         char *line_ptr;
 136                         /* Create leading directories */
 137                         line_ptr = strrchr(new_filename, '/');
 138                         if (line_ptr) {
 139                                 *line_ptr = '\0';
 140                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 141                                 *line_ptr = '/';
 142                         }
 143                         dst_stream = xfopen(new_filename, "w+");
 144                         backup_filename = NULL;
 145                 } else {
 146                         backup_filename = xmalloc(strlen(new_filename) + 6);
 147                         strcpy(backup_filename, new_filename);
 148                         strcat(backup_filename, ".orig");
 149                         if (rename(new_filename, backup_filename) == -1) {
 150                                 bb_perror_msg_and_die("cannot create file %s",
 151                                                 backup_filename);
 152                         }
 153                         dst_stream = xfopen(new_filename, "w");
 154                 }
 155
 156                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
 157                         src_stream = NULL;
 158                 } else {
 159                         if (strcmp(original_filename, new_filename) == 0) {
 160                                 src_stream = xfopen(backup_filename, "r");
 161                         } else {
 162                                 src_stream = xfopen(original_filename, "r");
 163                         }
 164                 }
 165
 166                 printf("patching file %s\n", new_filename);
 167
 168                 /* Handle each hunk */
 169                 patch_line = xmalloc_fgets(patch_file);
 170                 while (patch_line) {
 171                         unsigned int count;
 172                         unsigned int src_beg_line;
 173                         unsigned int unused;
 174                         unsigned int hunk_offset_start = 0;
 175                         int hunk_error = 0;
 176
 177                         /* This bit should be improved */
 178                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 179                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 180                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 181                                 /* No more hunks for this file */
 182                                 break;
 183                         }
 184                         free(patch_line);
 185                         hunk_count++;
 186
 187                         if (src_beg_line && dest_beg_line) {
 188                                 /* Copy unmodified lines upto start of hunk */
 189                                 /* src_beg_line will be 0 if its a new file */
 190                                 count = src_beg_line - src_cur_line;
 191                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 192                                         bb_error_msg_and_die("bad src file");
 193                                 }
 194                                 src_cur_line += count;
 195                                 dest_cur_line += count;
 196                                 copy_trailing_lines_flag = 1;
 197                         }
 198                         hunk_offset_start = src_cur_line;
 199
 200                         while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
 201                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 202                                         char *src_line = NULL;
 203                                         if (src_stream) {
 204                                                 src_line = xmalloc_fgets(src_stream);
 205                                                 if (!src_line) {
 206                                                         hunk_error++;
 207                                                         break;
 208                                                 } else {
 209                                                         src_cur_line++;
 210                                                 }
 211                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 212                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
 213                                                         hunk_error++;
 214                                                         free(patch_line);
 215                                                         break;
 216                                                 }
 217                                                 free(src_line);
 218                                         }
 219                                         if (*patch_line == ' ') {
 220                                                 fputs(patch_line + 1, dst_stream);
 221                                                 dest_cur_line++;
 222                                         }
 223                                 } else if (*patch_line == '+') {
 224                                         fputs(patch_line + 1, dst_stream);
 225                                         dest_cur_line++;
 226                                 } else {
 227                                         break;
 228                                 }
 229                                 free(patch_line);
 230                         }
 231                         if (hunk_error) {
 232                                 bad_hunk_count++;
 233                         }
 234                 }
 235
 236                 /* Cleanup last patched file */
 237                 if (copy_trailing_lines_flag) {
 238                         copy_lines(src_stream, dst_stream, -1);
 239                 }
 240                 if (src_stream) {
 241                         fclose(src_stream);
 242                 }
 243                 if (dst_stream) {
 244                         fclose(dst_stream);
 245                 }
 246                 if (bad_hunk_count) {
 247                         if (!ret) {
 248                                 ret = 1;
 249                         }
 250                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 251                 } else {
 252                         /* It worked, we can remove the backup */
 253                         if (backup_filename) {
 254                                 unlink(backup_filename);
 255                         }
 256                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 257                                 /* The new patched file is empty, remove it */
 258                                 if (unlink(new_filename) == -1) {
 259                                         bb_perror_msg_and_die("cannot remove file %s", new_filename);
 260                                 }
 261                                 if (unlink(original_filename) == -1) {
 262                                         bb_perror_msg_and_die("cannot remove original file %s", new_filename);
 263                                 }
 264                         }
 265                 }
 266         }
 267
 268         /* 0 = SUCCESS
 269          * 1 = Some hunks failed
 270          * 2 = More serious problems
 271          */
 272         return(ret);
 273 }