update-cache.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7
   8 /*
   9  * Default to not allowing changes to the list of files. The
  10  * tool doesn't actually care, but this makes it harder to add
  11  * files to the revision control by mistake by doing something
  12  * like "git-update-cache *" and suddenly having all the object
  13  * files be revision controlled.
  14  */
  15 static int allow_add = 0, allow_remove = 0, allow_replace = 0, not_new = 0;
  16
  17 /* Three functions to allow overloaded pointer return; see linux/err.h */
  18 static inline void *ERR_PTR(long error)
  19 {
  20         return (void *) error;
  21 }
  22
  23 static inline long PTR_ERR(const void *ptr)
  24 {
  25         return (long) ptr;
  26 }
  27
  28 static inline long IS_ERR(const void *ptr)
  29 {
  30         return (unsigned long)ptr > (unsigned long)-1000L;
  31 }
  32
  33 static int add_file_to_cache(char *path)
  34 {
  35         int size, namelen, option, status;
  36         struct cache_entry *ce;
  37         struct stat st;
  38         int fd;
  39         char *target;
  40
  41         status = lstat(path, &st);
  42         if (status < 0 || S_ISDIR(st.st_mode)) {
  43                 /* When we used to have "path" and now we want to add
  44                  * "path/file", we need a way to remove "path" before
  45                  * being able to add "path/file".  However,
  46                  * "git-update-cache --remove path" would not work.
  47                  * --force-remove can be used but this is more user
  48                  * friendly, especially since we can do the opposite
  49                  * case just fine without --force-remove.
  50                  */
  51                 if (status == 0 || (errno == ENOENT || errno == ENOTDIR)) {
  52                         if (allow_remove)
  53                                 return remove_file_from_cache(path);
  54                 }
  55                 return error("open(\"%s\"): %s", path, strerror(errno));
  56         }
  57         namelen = strlen(path);
  58         size = cache_entry_size(namelen);
  59         ce = xmalloc(size);
  60         memset(ce, 0, size);
  61         memcpy(ce->name, path, namelen);
  62         fill_stat_cache_info(ce, &st);
  63         ce->ce_mode = create_ce_mode(st.st_mode);
  64         ce->ce_flags = htons(namelen);
  65         switch (st.st_mode & S_IFMT) {
  66         case S_IFREG:
  67                 fd = open(path, O_RDONLY);
  68                 if (fd < 0)
  69                         return -1;
  70                 if (index_fd(ce->sha1, fd, &st) < 0)
  71                         return -1;
  72                 break;
  73         case S_IFLNK:
  74                 target = xmalloc(st.st_size+1);
  75                 if (readlink(path, target, st.st_size+1) != st.st_size) {
  76                         free(target);
  77                         return -1;
  78                 }
  79                 if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
  80                         return -1;
  81                 free(target);
  82                 break;
  83         default:
  84                 return -1;
  85         }
  86         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
  87         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
  88         return add_cache_entry(ce, option);
  89 }
  90
  91 static int match_data(int fd, void *buffer, unsigned long size)
  92 {
  93         while (size) {
  94                 char compare[1024];
  95                 int ret = read(fd, compare, sizeof(compare));
  96
  97                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
  98                         return -1;
  99                 size -= ret;
 100                 buffer += ret;
 101         }
 102         return 0;
 103 }
 104
 105 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 106 {
 107         int match = -1;
 108         int fd = open(ce->name, O_RDONLY);
 109
 110         if (fd >= 0) {
 111                 void *buffer;
 112                 unsigned long size;
 113                 char type[20];
 114
 115                 buffer = read_sha1_file(ce->sha1, type, &size);
 116                 if (buffer) {
 117                         if (size == expected_size && !strcmp(type, "blob"))
 118                                 match = match_data(fd, buffer, size);
 119                         free(buffer);
 120                 }
 121                 close(fd);
 122         }
 123         return match;
 124 }
 125
 126 static int compare_link(struct cache_entry *ce, unsigned long expected_size)
 127 {
 128         int match = -1;
 129         char *target;
 130         void *buffer;
 131         unsigned long size;
 132         char type[10];
 133         int len;
 134
 135         target = xmalloc(expected_size);
 136         len = readlink(ce->name, target, expected_size);
 137         if (len != expected_size) {
 138                 free(target);
 139                 return -1;
 140         }
 141         buffer = read_sha1_file(ce->sha1, type, &size);
 142         if (!buffer) {
 143                 free(target);
 144                 return -1;
 145         }
 146         if (size == expected_size)
 147                 match = memcmp(buffer, target, size);
 148         free(buffer);
 149         free(target);
 150         return match;
 151 }
 152
 153 /*
 154  * "refresh" does not calculate a new sha1 file or bring the
 155  * cache up-to-date for mode/content changes. But what it
 156  * _does_ do is to "re-match" the stat information of a file
 157  * with the cache, so that you can refresh the cache for a
 158  * file that hasn't been changed but where the stat entry is
 159  * out of date.
 160  *
 161  * For example, you'd want to do this after doing a "git-read-tree",
 162  * to link up the stat cache details with the proper files.
 163  */
 164 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 165 {
 166         struct stat st;
 167         struct cache_entry *updated;
 168         int changed, size;
 169
 170         if (lstat(ce->name, &st) < 0)
 171                 return ERR_PTR(-errno);
 172
 173         changed = ce_match_stat(ce, &st);
 174         if (!changed)
 175                 return ce;
 176
 177         /*
 178          * If the mode or type has changed, there's no point in trying
 179          * to refresh the entry - it's not going to match
 180          */
 181         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 182                 return ERR_PTR(-EINVAL);
 183
 184         switch (st.st_mode & S_IFMT) {
 185         case S_IFREG:
 186                 if (compare_data(ce, st.st_size))
 187                         return ERR_PTR(-EINVAL);
 188                 break;
 189         case S_IFLNK:
 190                 if (compare_link(ce, st.st_size))
 191                         return ERR_PTR(-EINVAL);
 192                 break;
 193         default:
 194                 return ERR_PTR(-EINVAL);
 195         }
 196
 197         size = ce_size(ce);
 198         updated = xmalloc(size);
 199         memcpy(updated, ce, size);
 200         fill_stat_cache_info(updated, &st);
 201         return updated;
 202 }
 203
 204 static int refresh_cache(void)
 205 {
 206         int i;
 207         int has_errors = 0;
 208
 209         for (i = 0; i < active_nr; i++) {
 210                 struct cache_entry *ce, *new;
 211                 ce = active_cache[i];
 212                 if (ce_stage(ce)) {
 213                         printf("%s: needs merge\n", ce->name);
 214                         has_errors = 1;
 215                         while ((i < active_nr) &&
 216                                ! strcmp(active_cache[i]->name, ce->name))
 217                                 i++;
 218                         i--;
 219                         continue;
 220                 }
 221
 222                 new = refresh_entry(ce);
 223                 if (IS_ERR(new)) {
 224                         if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 225                                 printf("%s: needs update\n", ce->name);
 226                                 has_errors = 1;
 227                         }
 228                         continue;
 229                 }
 230                 active_cache_changed = 1;
 231                 /* You can NOT just free active_cache[i] here, since it
 232                  * might not be necessarily malloc()ed but can also come
 233                  * from mmap(). */
 234                 active_cache[i] = new;
 235         }
 236         return has_errors;
 237 }
 238
 239 /*
 240  * We fundamentally don't like some paths: we don't want
 241  * dot or dot-dot anywhere, and for obvious reasons don't
 242  * want to recurse into ".git" either.
 243  *
 244  * Also, we don't want double slashes or slashes at the
 245  * end that can make pathnames ambiguous.
 246  */
 247 static int verify_dotfile(const char *rest)
 248 {
 249         /*
 250          * The first character was '.', but that
 251          * has already been discarded, we now test
 252          * the rest.
 253          */
 254         switch (*rest) {
 255         /* "." is not allowed */
 256         case '\0': case '/':
 257                 return 0;
 258
 259         /*
 260          * ".git" followed by  NUL or slash is bad. This
 261          * shares the path end test with the ".." case.
 262          */
 263         case 'g':
 264                 if (rest[1] != 'i')
 265                         break;
 266                 if (rest[2] != 't')
 267                         break;
 268                 rest += 2;
 269         /* fallthrough */
 270         case '.':
 271                 if (rest[1] == '\0' || rest[1] == '/')
 272                         return 0;
 273         }
 274         return 1;
 275 }
 276
 277 static int verify_path(char *path)
 278 {
 279         char c;
 280
 281         goto inside;
 282         for (;;) {
 283                 if (!c)
 284                         return 1;
 285                 if (c == '/') {
 286 inside:
 287                         c = *path++;
 288                         switch (c) {
 289                         default:
 290                                 continue;
 291                         case '/': case '\0':
 292                                 break;
 293                         case '.':
 294                                 if (verify_dotfile(path))
 295                                         continue;
 296                         }
 297                         return 0;
 298                 }
 299                 c = *path++;
 300         }
 301 }
 302
 303 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 304 {
 305         int size, len, option;
 306         unsigned int mode;
 307         unsigned char sha1[20];
 308         struct cache_entry *ce;
 309
 310         if (sscanf(arg1, "%o", &mode) != 1)
 311                 return -1;
 312         if (get_sha1_hex(arg2, sha1))
 313                 return -1;
 314         if (!verify_path(arg3))
 315                 return -1;
 316
 317         len = strlen(arg3);
 318         size = cache_entry_size(len);
 319         ce = xmalloc(size);
 320         memset(ce, 0, size);
 321
 322         memcpy(ce->sha1, sha1, 20);
 323         memcpy(ce->name, arg3, len);
 324         ce->ce_flags = htons(len);
 325         ce->ce_mode = create_ce_mode(mode);
 326         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
 327         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
 328         return add_cache_entry(ce, option);
 329 }
 330
 331 static struct cache_file cache_file;
 332
 333 int main(int argc, char **argv)
 334 {
 335         int i, newfd, entries, has_errors = 0;
 336         int allow_options = 1;
 337
 338         newfd = hold_index_file_for_update(&cache_file, get_index_file());
 339         if (newfd < 0)
 340                 die("unable to create new cachefile");
 341
 342         entries = read_cache();
 343         if (entries < 0)
 344                 die("cache corrupted");
 345
 346         for (i = 1 ; i < argc; i++) {
 347                 char *path = argv[i];
 348
 349                 if (allow_options && *path == '-') {
 350                         if (!strcmp(path, "--")) {
 351                                 allow_options = 0;
 352                                 continue;
 353                         }
 354                         if (!strcmp(path, "--add")) {
 355                                 allow_add = 1;
 356                                 continue;
 357                         }
 358                         if (!strcmp(path, "--replace")) {
 359                                 allow_replace = 1;
 360                                 continue;
 361                         }
 362                         if (!strcmp(path, "--remove")) {
 363                                 allow_remove = 1;
 364                                 continue;
 365                         }
 366                         if (!strcmp(path, "--refresh")) {
 367                                 has_errors |= refresh_cache();
 368                                 continue;
 369                         }
 370                         if (!strcmp(path, "--cacheinfo")) {
 371                                 if (i+3 >= argc)
 372                                         die("git-update-cache: --cacheinfo <mode> <sha1> <path>");
 373                                 if (add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 374                                         die("git-update-cache: --cacheinfo cannot add %s", argv[i+3]);
 375                                 i += 3;
 376                                 continue;
 377                         }
 378                         if (!strcmp(path, "--force-remove")) {
 379                                 if (argc <= i + 1)
 380                                         die("git-update-cache: --force-remove <path>");
 381                                 if (remove_file_from_cache(argv[i+1]))
 382                                         die("git-update-cache: --force-remove cannot remove %s", argv[i+1]);
 383                                 i++;
 384                                 continue;
 385                         }
 386
 387                         if (!strcmp(path, "--ignore-missing")) {
 388                                 not_new = 1;
 389                                 continue;
 390                         }
 391                         die("unknown option %s", path);
 392                 }
 393                 if (!verify_path(path)) {
 394                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 395                         continue;
 396                 }
 397                 if (add_file_to_cache(path))
 398                         die("Unable to add %s to database", path);
 399         }
 400         if (write_cache(newfd, active_cache, active_nr) ||
 401             commit_index_file(&cache_file))
 402                 die("Unable to write new cachefile");
 403
 404         return has_errors ? 1 : 0;
 405 }