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