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 = strchr(filename_start_ptr, '\t');
  59         if (temp) *temp = 0;
  60
  61         /* skip over (patch_level) number of leading directories */
  62         for (i = 0; i < patch_level; i++) {
  63                 temp = strchr(filename_start_ptr, '/');
  64                 if (!temp)
  65                         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 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                 /* FIXME: patch_line NULL check?? */
 121
 122                 /* Extract the filename used before the patch was generated */
 123                 original_filename = extract_filename(patch_line, patch_level);
 124                 free(patch_line);
 125
 126                 patch_line = xmalloc_fgets(patch_file);
 127                 /* FIXME: NULL check?? */
 128                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 129                         ret = 2;
 130                         bb_error_msg("invalid patch");
 131                         continue;
 132                 }
 133                 new_filename = extract_filename(patch_line, patch_level);
 134                 free(patch_line);
 135
 136                 if (file_doesnt_exist(new_filename)) {
 137                         char *line_ptr;
 138                         /* Create leading directories */
 139                         line_ptr = strrchr(new_filename, '/');
 140                         if (line_ptr) {
 141                                 *line_ptr = '\0';
 142                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 143                                 *line_ptr = '/';
 144                         }
 145                         dst_stream = xfopen(new_filename, "w+");
 146                         backup_filename = NULL;
 147                 } else {
 148                         backup_filename = xmalloc(strlen(new_filename) + 6);
 149                         strcpy(backup_filename, new_filename);
 150                         strcat(backup_filename, ".orig");
 151                         if (rename(new_filename, backup_filename) == -1) {
 152                                 bb_perror_msg_and_die("cannot create file %s",
 153                                                 backup_filename);
 154                         }
 155                         dst_stream = xfopen(new_filename, "w");
 156                 }
 157
 158                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
 159                         src_stream = NULL;
 160                 } else {
 161                         if (strcmp(original_filename, new_filename) == 0) {
 162                                 src_stream = xfopen(backup_filename, "r");
 163                         } else {
 164                                 src_stream = xfopen(original_filename, "r");
 165                         }
 166                 }
 167
 168                 printf("patching file %s\n", new_filename);
 169
 170                 /* Handle each hunk */
 171                 patch_line = xmalloc_fgets(patch_file);
 172                 while (patch_line) {
 173                         unsigned int count;
 174                         unsigned int src_beg_line;
 175                         unsigned int unused;
 176                         unsigned int hunk_offset_start = 0;
 177                         int hunk_error = 0;
 178
 179                         /* This bit should be improved */
 180                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 181                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 182                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 183                                 /* No more hunks for this file */
 184                                 break;
 185                         }
 186                         free(patch_line);
 187                         hunk_count++;
 188
 189                         if (src_beg_line && dest_beg_line) {
 190                                 /* Copy unmodified lines upto start of hunk */
 191                                 /* src_beg_line will be 0 if its a new file */
 192                                 count = src_beg_line - src_cur_line;
 193                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 194                                         bb_error_msg_and_die("bad src file");
 195                                 }
 196                                 src_cur_line += count;
 197                                 dest_cur_line += count;
 198                                 copy_trailing_lines_flag = 1;
 199                         }
 200                         hunk_offset_start = src_cur_line;
 201
 202                         while ((patch_line = xmalloc_fgets(patch_file)) != NULL) {
 203                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 204                                         char *src_line = NULL;
 205                                         if (src_stream) {
 206                                                 src_line = xmalloc_fgets(src_stream);
 207                                                 if (!src_line) {
 208                                                         hunk_error++;
 209                                                         break;
 210                                                 } else {
 211                                                         src_cur_line++;
 212                                                 }
 213                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 214                                                         bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
 215                                                         hunk_error++;
 216                                                         free(patch_line);
 217                                                         /* Probably need to find next hunk, etc... */
 218                                                         /* but for now we just bail out */
 219                                                         patch_line = NULL;
 220                                                         break;
 221                                                 }
 222                                                 free(src_line);
 223                                         }
 224                                         if (*patch_line == ' ') {
 225                                                 fputs(patch_line + 1, dst_stream);
 226                                                 dest_cur_line++;
 227                                         }
 228                                 } else if (*patch_line == '+') {
 229                                         fputs(patch_line + 1, dst_stream);
 230                                         dest_cur_line++;
 231                                 } else {
 232                                         break;
 233                                 }
 234                                 free(patch_line);
 235                         }
 236                         if (hunk_error) {
 237                                 bad_hunk_count++;
 238                         }
 239                 }
 240
 241                 /* Cleanup last patched file */
 242                 if (copy_trailing_lines_flag) {
 243                         copy_lines(src_stream, dst_stream, -1);
 244                 }
 245                 if (src_stream) {
 246                         fclose(src_stream);
 247                 }
 248                 if (dst_stream) {
 249                         fclose(dst_stream);
 250                 }
 251                 if (bad_hunk_count) {
 252                         if (!ret) {
 253                                 ret = 1;
 254                         }
 255                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 256                 } else {
 257                         /* It worked, we can remove the backup */
 258                         if (backup_filename) {
 259                                 unlink(backup_filename);
 260                         }
 261                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 262                                 /* The new patched file is empty, remove it */
 263                                 xunlink(new_filename);
 264                                 if (strcmp(new_filename, original_filename) != 0)
 265                                         xunlink(original_filename);
 266                         }
 267                 }
 268         }
 269
 270         /* 0 = SUCCESS
 271          * 1 = Some hunks failed
 272          * 2 = More serious problems
 273          */
 274         return ret;
 275 }