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 int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
  30 {
  31         int i = 0;
  32
  33         while (src_stream && (i < lines_count)) {
  34                 char *line;
  35                 line = bb_get_line_from_file(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 unsigned char *extract_filename(char *line, unsigned short patch_level)
  56 {
  57         char *filename_start_ptr = line + 4;
  58         int i;
  59
  60         /* Terminate string at end of source filename */
  61         {
  62                 char *line_ptr;
  63                 line_ptr = strchr(filename_start_ptr, '\t');
  64                 if (!line_ptr) {
  65                         bb_perror_msg("Malformed line %s", line);
  66                         return(NULL);
  67                 }
  68                 *line_ptr = '\0';
  69         }
  70
  71         /* Skip over (patch_level) number of leading directories */
  72         for (i = 0; i < patch_level; i++) {
  73                 char *dirname_ptr;
  74
  75                 dirname_ptr = strchr(filename_start_ptr, '/');
  76                 if (!dirname_ptr) {
  77                         break;
  78                 }
  79                 filename_start_ptr = dirname_ptr + 1;
  80         }
  81
  82         return(bb_xstrdup(filename_start_ptr));
  83 }
  84
  85 static int file_doesnt_exist(const char *filename)
  86 {
  87         struct stat statbuf;
  88         return(stat(filename, &statbuf));
  89 }
  90
  91 extern int patch_main(int argc, char **argv)
  92 {
  93         unsigned int patch_level = -1;
  94         char *patch_line;
  95         int ret;
  96         FILE *patch_file = NULL;
  97
  98         {
  99                 char *p, *i;
 100                 ret = bb_getopt_ulflags(argc, argv, "p:i:", &p, &i);
 101                 if (ret & 1)
 102                         patch_level = bb_xgetlarg(p, 10, -1, USHRT_MAX);
 103                 if (ret & 2) {
 104                         patch_file = bb_xfopen(i, "r");
 105                 } else {
 106                         patch_file = stdin;
 107                 }
 108                 ret = 0;
 109         }
 110
 111         patch_line = bb_get_line_from_file(patch_file);
 112         while (patch_line) {
 113                 FILE *src_stream;
 114                 FILE *dst_stream;
 115                 char *original_filename;
 116                 char *new_filename;
 117                 char *backup_filename;
 118                 unsigned int src_cur_line = 1;
 119                 unsigned int dest_cur_line = 0;
 120                 unsigned int dest_beg_line;
 121                 unsigned int bad_hunk_count = 0;
 122                 unsigned int hunk_count = 0;
 123                 char copy_trailing_lines_flag = 0;
 124
 125                 /* Skip everything upto the "---" marker
 126                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 127                  */
 128                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
 129                         free(patch_line);
 130                         patch_line = bb_get_line_from_file(patch_file);
 131                 }
 132
 133                 /* Extract the filename used before the patch was generated */
 134                 original_filename = extract_filename(patch_line, patch_level);
 135                 free(patch_line);
 136
 137                 patch_line = bb_get_line_from_file(patch_file);
 138                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 139                         ret = 2;
 140                         bb_error_msg("Invalid patch");
 141                         continue;
 142                 }
 143                 new_filename = extract_filename(patch_line, patch_level);
 144                 free(patch_line);
 145
 146                 if (file_doesnt_exist(new_filename)) {
 147                         char *line_ptr;
 148                         /* Create leading directories */
 149                         line_ptr = strrchr(new_filename, '/');
 150                         if (line_ptr) {
 151                                 *line_ptr = '\0';
 152                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 153                                 *line_ptr = '/';
 154                         }
 155                         dst_stream = bb_xfopen(new_filename, "w+");
 156                         backup_filename = NULL;
 157                 } else {
 158                         backup_filename = xmalloc(strlen(new_filename) + 6);
 159                         strcpy(backup_filename, new_filename);
 160                         strcat(backup_filename, ".orig");
 161                         if (rename(new_filename, backup_filename) == -1) {
 162                                 bb_perror_msg_and_die("Couldnt create file %s",
 163                                                 backup_filename);
 164                         }
 165                         dst_stream = bb_xfopen(new_filename, "w");
 166                 }
 167
 168                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
 169                         src_stream = NULL;
 170                 } else {
 171                         if (strcmp(original_filename, new_filename) == 0) {
 172                                 src_stream = bb_xfopen(backup_filename, "r");
 173                         } else {
 174                                 src_stream = bb_xfopen(original_filename, "r");
 175                         }
 176                 }
 177
 178                 printf("patching file %s\n", new_filename);
 179
 180                 /* Handle each hunk */
 181                 patch_line = bb_get_line_from_file(patch_file);
 182                 while (patch_line) {
 183                         unsigned int count;
 184                         unsigned int src_beg_line;
 185                         unsigned int unused;
 186                         unsigned int hunk_offset_start = 0;
 187                         int hunk_error = 0;
 188
 189                         /* This bit should be improved */
 190                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 191                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 192                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 193                                 /* No more hunks for this file */
 194                                 break;
 195                         }
 196                         free(patch_line);
 197                         hunk_count++;
 198
 199                         if (src_beg_line && dest_beg_line) {
 200                                 /* Copy unmodified lines upto start of hunk */
 201                                 /* src_beg_line will be 0 if its a new file */
 202                                 count = src_beg_line - src_cur_line;
 203                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 204                                         bb_error_msg_and_die("Bad src file");
 205                                 }
 206                                 src_cur_line += count;
 207                                 dest_cur_line += count;
 208                                 copy_trailing_lines_flag = 1;
 209                         }
 210                         hunk_offset_start = src_cur_line;
 211
 212                         while ((patch_line = bb_get_line_from_file(patch_file)) != NULL) {
 213                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 214                                         char *src_line = NULL;
 215                                         if (src_stream) {
 216                                                 src_line = bb_get_line_from_file(src_stream);
 217                                                 if (!src_line) {
 218                                                         hunk_error++;
 219                                                         break;
 220                                                 } else {
 221                                                         src_cur_line++;
 222                                                 }
 223                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 224                                                         bb_error_msg("Hunk #%d FAILED at %d.", hunk_count, hunk_offset_start);
 225                                                         hunk_error++;
 226                                                         free(patch_line);
 227                                                         break;
 228                                                 }
 229                                                 free(src_line);
 230                                         }
 231                                         if (*patch_line == ' ') {
 232                                                 fputs(patch_line + 1, dst_stream);
 233                                                 dest_cur_line++;
 234                                         }
 235                                 } else if (*patch_line == '+') {
 236                                         fputs(patch_line + 1, dst_stream);
 237                                         dest_cur_line++;
 238                                 } else {
 239                                         break;
 240                                 }
 241                                 free(patch_line);
 242                         }
 243                         if (hunk_error) {
 244                                 bad_hunk_count++;
 245                         }
 246                 }
 247
 248                 /* Cleanup last patched file */
 249                 if (copy_trailing_lines_flag) {
 250                         copy_lines(src_stream, dst_stream, -1);
 251                 }
 252                 if (src_stream) {
 253                         fclose(src_stream);
 254                 }
 255                 if (dst_stream) {
 256                         fclose(dst_stream);
 257                 }
 258                 if (bad_hunk_count) {
 259                         if (!ret) {
 260                                 ret = 1;
 261                         }
 262                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 263                 } else {
 264                         /* It worked, we can remove the backup */
 265                         if (backup_filename) {
 266                                 unlink(backup_filename);
 267                         }
 268                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 269                                 /* The new patched file is empty, remove it */
 270                                 if (unlink(new_filename) == -1) {
 271                                         bb_perror_msg_and_die("Couldnt remove file %s", new_filename);
 272                                 }
 273                                 if (unlink(original_filename) == -1) {
 274                                         bb_perror_msg_and_die("Couldnt remove original file %s", new_filename);
 275                                 }
 276                         }
 277                 }
 278         }
 279
 280         /* 0 = SUCCESS
 281          * 1 = Some hunks failed
 282          * 2 = More serious problems
 283          */
 284         return(ret);
 285 }