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, quiet = 0, info_only = 0;
  16 static int force_remove;
  17
  18 /* Three functions to allow overloaded pointer return; see linux/err.h */
  19 static inline void *ERR_PTR(long error)
  20 {
  21         return (void *) error;
  22 }
  23
  24 static inline long PTR_ERR(const void *ptr)
  25 {
  26         return (long) ptr;
  27 }
  28
  29 static inline long IS_ERR(const void *ptr)
  30 {
  31         return (unsigned long)ptr > (unsigned long)-1000L;
  32 }
  33
  34 static int add_file_to_cache(char *path)
  35 {
  36         int size, namelen, option, status;
  37         struct cache_entry *ce;
  38         struct stat st;
  39         int fd;
  40         char *target;
  41
  42         status = lstat(path, &st);
  43         if (status < 0 || S_ISDIR(st.st_mode)) {
  44                 /* When we used to have "path" and now we want to add
  45                  * "path/file", we need a way to remove "path" before
  46                  * being able to add "path/file".  However,
  47                  * "git-update-cache --remove path" would not work.
  48                  * --force-remove can be used but this is more user
  49                  * friendly, especially since we can do the opposite
  50                  * case just fine without --force-remove.
  51                  */
  52                 if (status == 0 || (errno == ENOENT || errno == ENOTDIR)) {
  53                         if (allow_remove)
  54                                 return remove_file_from_cache(path);
  55                 }
  56                 return error("open(\"%s\"): %s", path, strerror(errno));
  57         }
  58         namelen = strlen(path);
  59         size = cache_entry_size(namelen);
  60         ce = xmalloc(size);
  61         memset(ce, 0, size);
  62         memcpy(ce->name, path, namelen);
  63         fill_stat_cache_info(ce, &st);
  64         ce->ce_mode = create_ce_mode(st.st_mode);
  65         ce->ce_flags = htons(namelen);
  66         switch (st.st_mode & S_IFMT) {
  67         case S_IFREG:
  68                 fd = open(path, O_RDONLY);
  69                 if (fd < 0)
  70                         return -1;
  71                 if (index_fd(ce->sha1, fd, &st, !info_only, NULL) < 0)
  72                         return -1;
  73                 break;
  74         case S_IFLNK:
  75                 target = xmalloc(st.st_size+1);
  76                 if (readlink(path, target, st.st_size+1) != st.st_size) {
  77                         free(target);
  78                         return -1;
  79                 }
  80                 if (info_only) {
  81                         unsigned char hdr[50];
  82                         int hdrlen;
  83                         write_sha1_file_prepare(target, st.st_size, "blob",
  84                                                 ce->sha1, hdr, &hdrlen);
  85                 } else if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
  86                         return -1;
  87                 free(target);
  88                 break;
  89         default:
  90                 return -1;
  91         }
  92         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
  93         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
  94         return add_cache_entry(ce, option);
  95 }
  96
  97 static int match_data(int fd, void *buffer, unsigned long size)
  98 {
  99         while (size) {
 100                 char compare[1024];
 101                 int ret = read(fd, compare, sizeof(compare));
 102
 103                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 104                         return -1;
 105                 size -= ret;
 106                 buffer += ret;
 107         }
 108         return 0;
 109 }
 110
 111 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 112 {
 113         int match = -1;
 114         int fd = open(ce->name, O_RDONLY);
 115
 116         if (fd >= 0) {
 117                 void *buffer;
 118                 unsigned long size;
 119                 char type[20];
 120
 121                 buffer = read_sha1_file(ce->sha1, type, &size);
 122                 if (buffer) {
 123                         if (size == expected_size && !strcmp(type, "blob"))
 124                                 match = match_data(fd, buffer, size);
 125                         free(buffer);
 126                 }
 127                 close(fd);
 128         }
 129         return match;
 130 }
 131
 132 static int compare_link(struct cache_entry *ce, unsigned long expected_size)
 133 {
 134         int match = -1;
 135         char *target;
 136         void *buffer;
 137         unsigned long size;
 138         char type[10];
 139         int len;
 140
 141         target = xmalloc(expected_size);
 142         len = readlink(ce->name, target, expected_size);
 143         if (len != expected_size) {
 144                 free(target);
 145                 return -1;
 146         }
 147         buffer = read_sha1_file(ce->sha1, type, &size);
 148         if (!buffer) {
 149                 free(target);
 150                 return -1;
 151         }
 152         if (size == expected_size)
 153                 match = memcmp(buffer, target, size);
 154         free(buffer);
 155         free(target);
 156         return match;
 157 }
 158
 159 /*
 160  * "refresh" does not calculate a new sha1 file or bring the
 161  * cache up-to-date for mode/content changes. But what it
 162  * _does_ do is to "re-match" the stat information of a file
 163  * with the cache, so that you can refresh the cache for a
 164  * file that hasn't been changed but where the stat entry is
 165  * out of date.
 166  *
 167  * For example, you'd want to do this after doing a "git-read-tree",
 168  * to link up the stat cache details with the proper files.
 169  */
 170 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 171 {
 172         struct stat st;
 173         struct cache_entry *updated;
 174         int changed, size;
 175
 176         if (lstat(ce->name, &st) < 0)
 177                 return ERR_PTR(-errno);
 178
 179         changed = ce_match_stat(ce, &st);
 180         if (!changed)
 181                 return ce;
 182
 183         /*
 184          * If the mode or type has changed, there's no point in trying
 185          * to refresh the entry - it's not going to match
 186          */
 187         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 188                 return ERR_PTR(-EINVAL);
 189
 190         switch (st.st_mode & S_IFMT) {
 191         case S_IFREG:
 192                 if (compare_data(ce, st.st_size))
 193                         return ERR_PTR(-EINVAL);
 194                 break;
 195         case S_IFLNK:
 196                 if (compare_link(ce, st.st_size))
 197                         return ERR_PTR(-EINVAL);
 198                 break;
 199         default:
 200                 return ERR_PTR(-EINVAL);
 201         }
 202
 203         size = ce_size(ce);
 204         updated = xmalloc(size);
 205         memcpy(updated, ce, size);
 206         fill_stat_cache_info(updated, &st);
 207         return updated;
 208 }
 209
 210 static int refresh_cache(void)
 211 {
 212         int i;
 213         int has_errors = 0;
 214
 215         for (i = 0; i < active_nr; i++) {
 216                 struct cache_entry *ce, *new;
 217                 ce = active_cache[i];
 218                 if (ce_stage(ce)) {
 219                         printf("%s: needs merge\n", ce->name);
 220                         has_errors = 1;
 221                         while ((i < active_nr) &&
 222                                ! strcmp(active_cache[i]->name, ce->name))
 223                                 i++;
 224                         i--;
 225                         continue;
 226                 }
 227
 228                 new = refresh_entry(ce);
 229                 if (IS_ERR(new)) {
 230                         if (not_new && PTR_ERR(new) == -ENOENT)
 231                                 continue;
 232                         if (quiet)
 233                                 continue;
 234                         printf("%s: needs update\n", ce->name);
 235                         has_errors = 1;
 236                         continue;
 237                 }
 238                 active_cache_changed = 1;
 239                 /* You can NOT just free active_cache[i] here, since it
 240                  * might not be necessarily malloc()ed but can also come
 241                  * from mmap(). */
 242                 active_cache[i] = new;
 243         }
 244         return has_errors;
 245 }
 246
 247 /*
 248  * We fundamentally don't like some paths: we don't want
 249  * dot or dot-dot anywhere, and for obvious reasons don't
 250  * want to recurse into ".git" either.
 251  *
 252  * Also, we don't want double slashes or slashes at the
 253  * end that can make pathnames ambiguous.
 254  */
 255 static int verify_dotfile(const char *rest)
 256 {
 257         /*
 258          * The first character was '.', but that
 259          * has already been discarded, we now test
 260          * the rest.
 261          */
 262         switch (*rest) {
 263         /* "." is not allowed */
 264         case '\0': case '/':
 265                 return 0;
 266
 267         /*
 268          * ".git" followed by  NUL or slash is bad. This
 269          * shares the path end test with the ".." case.
 270          */
 271         case 'g':
 272                 if (rest[1] != 'i')
 273                         break;
 274                 if (rest[2] != 't')
 275                         break;
 276                 rest += 2;
 277         /* fallthrough */
 278         case '.':
 279                 if (rest[1] == '\0' || rest[1] == '/')
 280                         return 0;
 281         }
 282         return 1;
 283 }
 284
 285 static int verify_path(char *path)
 286 {
 287         char c;
 288
 289         goto inside;
 290         for (;;) {
 291                 if (!c)
 292                         return 1;
 293                 if (c == '/') {
 294 inside:
 295                         c = *path++;
 296                         switch (c) {
 297                         default:
 298                                 continue;
 299                         case '/': case '\0':
 300                                 break;
 301                         case '.':
 302                                 if (verify_dotfile(path))
 303                                         continue;
 304                         }
 305                         return 0;
 306                 }
 307                 c = *path++;
 308         }
 309 }
 310
 311 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 312 {
 313         int size, len, option;
 314         unsigned int mode;
 315         unsigned char sha1[20];
 316         struct cache_entry *ce;
 317
 318         if (sscanf(arg1, "%o", &mode) != 1)
 319                 return -1;
 320         if (get_sha1_hex(arg2, sha1))
 321                 return -1;
 322         if (!verify_path(arg3))
 323                 return -1;
 324
 325         len = strlen(arg3);
 326         size = cache_entry_size(len);
 327         ce = xmalloc(size);
 328         memset(ce, 0, size);
 329
 330         memcpy(ce->sha1, sha1, 20);
 331         memcpy(ce->name, arg3, len);
 332         ce->ce_flags = htons(len);
 333         ce->ce_mode = create_ce_mode(mode);
 334         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
 335         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
 336         return add_cache_entry(ce, option);
 337 }
 338
 339 static struct cache_file cache_file;
 340
 341 int main(int argc, char **argv)
 342 {
 343         int i, newfd, entries, has_errors = 0;
 344         int allow_options = 1;
 345
 346         newfd = hold_index_file_for_update(&cache_file, get_index_file());
 347         if (newfd < 0)
 348                 die("unable to create new cachefile");
 349
 350         entries = read_cache();
 351         if (entries < 0)
 352                 die("cache corrupted");
 353
 354         for (i = 1 ; i < argc; i++) {
 355                 char *path = argv[i];
 356
 357                 if (allow_options && *path == '-') {
 358                         if (!strcmp(path, "--")) {
 359                                 allow_options = 0;
 360                                 continue;
 361                         }
 362                         if (!strcmp(path, "-q")) {
 363                                 quiet = 1;
 364                                 continue;
 365                         }
 366                         if (!strcmp(path, "--add")) {
 367                                 allow_add = 1;
 368                                 continue;
 369                         }
 370                         if (!strcmp(path, "--replace")) {
 371                                 allow_replace = 1;
 372                                 continue;
 373                         }
 374                         if (!strcmp(path, "--remove")) {
 375                                 allow_remove = 1;
 376                                 continue;
 377                         }
 378                         if (!strcmp(path, "--refresh")) {
 379                                 has_errors |= refresh_cache();
 380                                 continue;
 381                         }
 382                         if (!strcmp(path, "--cacheinfo")) {
 383                                 if (i+3 >= argc)
 384                                         die("git-update-cache: --cacheinfo <mode> <sha1> <path>");
 385                                 if (add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 386                                         die("git-update-cache: --cacheinfo cannot add %s", argv[i+3]);
 387                                 i += 3;
 388                                 continue;
 389                         }
 390                         if (!strcmp(path, "--info-only")) {
 391                                 info_only = 1;
 392                                 continue;
 393                         }
 394                         if (!strcmp(path, "--force-remove")) {
 395                                 force_remove = 1;
 396                                 continue;
 397                         }
 398
 399                         if (!strcmp(path, "--ignore-missing")) {
 400                                 not_new = 1;
 401                                 continue;
 402                         }
 403                         die("unknown option %s", path);
 404                 }
 405                 if (!verify_path(path)) {
 406                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 407                         continue;
 408                 }
 409                 if (force_remove) {
 410                         if (remove_file_from_cache(path))
 411                                 die("git-update-cache: --force-remove cannot remove %s", path);
 412                         continue;
 413                 }
 414                 if (add_file_to_cache(path))
 415                         die("Unable to add %s to database", path);
 416         }
 417         if (write_cache(newfd, active_cache, active_nr) ||
 418             commit_index_file(&cache_file))
 419                 die("Unable to write new cachefile");
 420
 421         return has_errors ? 1 : 0;
 422 }