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