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