update-cache.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include <signal.h>
   7 #include "cache.h"
   8
   9 /*
  10  * Default to not allowing changes to the list of files. The
  11  * tool doesn't actually care, but this makes it harder to add
  12  * files to the revision control by mistake by doing something
  13  * like "update-cache *" and suddenly having all the object
  14  * files be revision controlled.
  15  */
  16 static int allow_add = 0, allow_remove = 0, not_new = 0;
  17
  18 /*
  19  * update-cache --refresh may not touch anything at all, in which case
  20  * writing 1.6MB of the same thing is a waste.
  21  */
  22 static int cache_changed = 0;
  23
  24 /* Three functions to allow overloaded pointer return; see linux/err.h */
  25 static inline void *ERR_PTR(long error)
  26 {
  27         return (void *) error;
  28 }
  29
  30 static inline long PTR_ERR(const void *ptr)
  31 {
  32         return (long) ptr;
  33 }
  34
  35 static inline long IS_ERR(const void *ptr)
  36 {
  37         return (unsigned long)ptr > (unsigned long)-1000L;
  38 }
  39
  40 /*
  41  * This only updates the "non-critical" parts of the directory
  42  * cache, ie the parts that aren't tracked by GIT, and only used
  43  * to validate the cache.
  44  */
  45 static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  46 {
  47         ce->ce_ctime.sec = htonl(st->st_ctime);
  48         ce->ce_mtime.sec = htonl(st->st_mtime);
  49 #ifdef NSEC
  50         ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
  51         ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
  52 #endif
  53         ce->ce_dev = htonl(st->st_dev);
  54         ce->ce_ino = htonl(st->st_ino);
  55         ce->ce_uid = htonl(st->st_uid);
  56         ce->ce_gid = htonl(st->st_gid);
  57         ce->ce_size = htonl(st->st_size);
  58 }
  59
  60 static int add_file_to_cache_1(char *path)
  61 {
  62         int size, namelen;
  63         struct cache_entry *ce;
  64         struct stat st;
  65         int fd;
  66         char *target;
  67
  68         if (lstat(path, &st) < 0) {
  69                 if (errno == ENOENT || errno == ENOTDIR) {
  70                         if (allow_remove)
  71                                 return remove_file_from_cache(path);
  72                 }
  73                 return -1;
  74         }
  75         namelen = strlen(path);
  76         size = cache_entry_size(namelen);
  77         ce = xmalloc(size);
  78         memset(ce, 0, size);
  79         memcpy(ce->name, path, namelen);
  80         fill_stat_cache_info(ce, &st);
  81         ce->ce_mode = create_ce_mode(st.st_mode);
  82         ce->ce_flags = htons(namelen);
  83         switch (st.st_mode & S_IFMT) {
  84         case S_IFREG:
  85                 fd = open(path, O_RDONLY);
  86                 if (fd < 0)
  87                         return -1;
  88                 if (index_fd(ce->sha1, fd, &st) < 0)
  89                         return -1;
  90                 break;
  91         case S_IFLNK:
  92                 target = xmalloc(st.st_size+1);
  93                 if (readlink(path, target, st.st_size+1) != st.st_size) {
  94                         free(target);
  95                         return -1;
  96                 }
  97                 if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
  98                         return -1;
  99                 free(target);
 100                 break;
 101         default:
 102                 return -1;
 103         }
 104         if (!cache_changed) {
 105                 /* If we have not smudged the cache, be careful
 106                  * to keep it clean.  Find out if we have a matching
 107                  * cache entry that add_cache_entry would replace with,
 108                  * and if it matches then do not bother calling it.
 109                  */
 110                 int pos = cache_name_pos(ce->name, namelen);
 111                 if ((0 <= pos) &&
 112                     !memcmp(active_cache[pos], ce, sizeof(*ce))) {
 113                         free(ce);
 114                         /* magic to tell add_file_to_cache that
 115                          * we have not updated anything.
 116                          */
 117                         return 999;
 118                 }
 119         }
 120         return add_cache_entry(ce, allow_add);
 121 }
 122
 123 static int add_file_to_cache(char *path)
 124 {
 125         int ret = add_file_to_cache_1(path);
 126         if (ret == 0)
 127                 cache_changed = 1;
 128         else if (ret == 999)
 129                 ret = 0;
 130         return ret;
 131 }
 132
 133 static int match_data(int fd, void *buffer, unsigned long size)
 134 {
 135         while (size) {
 136                 char compare[1024];
 137                 int ret = read(fd, compare, sizeof(compare));
 138
 139                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 140                         return -1;
 141                 size -= ret;
 142                 buffer += ret;
 143         }
 144         return 0;
 145 }
 146
 147 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 148 {
 149         int match = -1;
 150         int fd = open(ce->name, O_RDONLY);
 151
 152         if (fd >= 0) {
 153                 void *buffer;
 154                 unsigned long size;
 155                 char type[10];
 156
 157                 buffer = read_sha1_file(ce->sha1, type, &size);
 158                 if (buffer) {
 159                         if (size == expected_size && !strcmp(type, "blob"))
 160                                 match = match_data(fd, buffer, size);
 161                         free(buffer);
 162                 }
 163                 close(fd);
 164         }
 165         return match;
 166 }
 167
 168 static int compare_link(struct cache_entry *ce, unsigned long expected_size)
 169 {
 170         int match = -1;
 171         char *target;
 172         void *buffer;
 173         unsigned long size;
 174         char type[10];
 175         int len;
 176
 177         target = xmalloc(expected_size);
 178         len = readlink(ce->name, target, expected_size);
 179         if (len != expected_size) {
 180                 free(target);
 181                 return -1;
 182         }
 183         buffer = read_sha1_file(ce->sha1, type, &size);
 184         if (!buffer) {
 185                 free(target);
 186                 return -1;
 187         }
 188         if (size == expected_size)
 189                 match = memcmp(buffer, target, size);
 190         free(buffer);
 191         free(target);
 192         return match;
 193 }
 194
 195 /*
 196  * "refresh" does not calculate a new sha1 file or bring the
 197  * cache up-to-date for mode/content changes. But what it
 198  * _does_ do is to "re-match" the stat information of a file
 199  * with the cache, so that you can refresh the cache for a
 200  * file that hasn't been changed but where the stat entry is
 201  * out of date.
 202  *
 203  * For example, you'd want to do this after doing a "read-tree",
 204  * to link up the stat cache details with the proper files.
 205  */
 206 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 207 {
 208         struct stat st;
 209         struct cache_entry *updated;
 210         int changed, size;
 211
 212         if (lstat(ce->name, &st) < 0)
 213                 return ERR_PTR(-errno);
 214
 215         changed = cache_match_stat(ce, &st);
 216         if (!changed)
 217                 return ce;
 218
 219         /*
 220          * If the mode or type has changed, there's no point in trying
 221          * to refresh the entry - it's not going to match
 222          */
 223         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 224                 return ERR_PTR(-EINVAL);
 225
 226         switch (st.st_mode & S_IFMT) {
 227         case S_IFREG:
 228                 if (compare_data(ce, st.st_size))
 229                         return ERR_PTR(-EINVAL);
 230                 break;
 231         case S_IFLNK:
 232                 if (compare_link(ce, st.st_size))
 233                         return ERR_PTR(-EINVAL);
 234                 break;
 235         default:
 236                 return ERR_PTR(-EINVAL);
 237         }
 238
 239         cache_changed = 1;
 240         size = ce_size(ce);
 241         updated = xmalloc(size);
 242         memcpy(updated, ce, size);
 243         fill_stat_cache_info(updated, &st);
 244         return updated;
 245 }
 246
 247 static int refresh_cache(void)
 248 {
 249         int i;
 250         int has_errors = 0;
 251
 252         for (i = 0; i < active_nr; i++) {
 253                 struct cache_entry *ce, *new;
 254                 ce = active_cache[i];
 255                 if (ce_stage(ce)) {
 256                         printf("%s: needs merge\n", ce->name);
 257                         has_errors = 1;
 258                         while ((i < active_nr) &&
 259                                ! strcmp(active_cache[i]->name, ce->name))
 260                                 i++;
 261                         i--;
 262                         continue;
 263                 }
 264
 265                 new = refresh_entry(ce);
 266                 if (IS_ERR(new)) {
 267                         if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 268                                 printf("%s: needs update\n", ce->name);
 269                                 has_errors = 1;
 270                         }
 271                         continue;
 272                 }
 273                 active_cache[i] = new;
 274         }
 275         return has_errors;
 276 }
 277
 278 /*
 279  * We fundamentally don't like some paths: we don't want
 280  * dot or dot-dot anywhere, and in fact, we don't even want
 281  * any other dot-files (.git or anything else). They
 282  * are hidden, for chist sake.
 283  *
 284  * Also, we don't want double slashes or slashes at the
 285  * end that can make pathnames ambiguous.
 286  */
 287 static int verify_path(char *path)
 288 {
 289         char c;
 290
 291         goto inside;
 292         for (;;) {
 293                 if (!c)
 294                         return 1;
 295                 if (c == '/') {
 296 inside:
 297                         c = *path++;
 298                         if (c != '/' && c != '.' && c != '\0')
 299                                 continue;
 300                         return 0;
 301                 }
 302                 c = *path++;
 303         }
 304 }
 305
 306 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 307 {
 308         int size, len;
 309         unsigned int mode;
 310         unsigned char sha1[20];
 311         struct cache_entry *ce;
 312
 313         if (sscanf(arg1, "%o", &mode) != 1)
 314                 return -1;
 315         if (get_sha1_hex(arg2, sha1))
 316                 return -1;
 317         if (!verify_path(arg3))
 318                 return -1;
 319
 320         cache_changed = 1;
 321         len = strlen(arg3);
 322         size = cache_entry_size(len);
 323         ce = xmalloc(size);
 324         memset(ce, 0, size);
 325
 326         memcpy(ce->sha1, sha1, 20);
 327         memcpy(ce->name, arg3, len);
 328         ce->ce_flags = htons(len);
 329         ce->ce_mode = create_ce_mode(mode);
 330         return add_cache_entry(ce, allow_add);
 331 }
 332
 333 static const char *lockfile_name = NULL;
 334
 335 static void remove_lock_file(void)
 336 {
 337         if (lockfile_name)
 338                 unlink(lockfile_name);
 339 }
 340
 341 static void remove_lock_file_on_signal(int signo)
 342 {
 343         remove_lock_file();
 344 }
 345
 346 int main(int argc, char **argv)
 347 {
 348         int i, newfd, entries, has_errors = 0;
 349         int allow_options = 1;
 350         static char lockfile[MAXPATHLEN+1];
 351         const char *indexfile = get_index_file();
 352
 353         snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);
 354
 355         newfd = open(lockfile, O_RDWR | O_CREAT | O_EXCL, 0600);
 356         if (newfd < 0)
 357                 die("unable to create new cachefile");
 358
 359         signal(SIGINT, remove_lock_file_on_signal);
 360         atexit(remove_lock_file);
 361         lockfile_name = lockfile;
 362
 363         entries = read_cache();
 364         if (entries < 0)
 365                 die("cache corrupted");
 366
 367         for (i = 1 ; i < argc; i++) {
 368                 char *path = argv[i];
 369
 370                 if (allow_options && *path == '-') {
 371                         if (!strcmp(path, "--")) {
 372                                 allow_options = 0;
 373                                 continue;
 374                         }
 375                         if (!strcmp(path, "--add")) {
 376                                 allow_add = 1;
 377                                 continue;
 378                         }
 379                         if (!strcmp(path, "--remove")) {
 380                                 allow_remove = 1;
 381                                 continue;
 382                         }
 383                         if (!strcmp(path, "--refresh")) {
 384                                 has_errors |= refresh_cache();
 385                                 continue;
 386                         }
 387                         if (!strcmp(path, "--cacheinfo")) {
 388                                 if (i+3 >= argc || add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 389                                         die("update-cache: --cacheinfo <mode> <sha1> <path>");
 390                                 i += 3;
 391                                 continue;
 392                         }
 393                         if (!strcmp(path, "--force-remove")) {
 394                                 if (argc <= i + 1)
 395                                         die("update-cache: --force-remove <path>");
 396                                 if (remove_file_from_cache(argv[i+1]))
 397                                         die("update-cache: --force-remove cannot remove %s", argv[i+1]);
 398                                 i++;
 399                                 continue;
 400                         }
 401
 402                         if (!strcmp(path, "--ignore-missing")) {
 403                                 not_new = 1;
 404                                 continue;
 405                         }
 406                         die("unknown option %s", path);
 407                 }
 408                 if (!verify_path(path)) {
 409                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 410                         continue;
 411                 }
 412                 if (add_file_to_cache(path))
 413                         die("Unable to add %s to database", path);
 414         }
 415
 416         if (!cache_changed)
 417                 unlink(lockfile);
 418         else if (write_cache(newfd, active_cache, active_nr) ||
 419                  rename(lockfile, indexfile))
 420                 die("Unable to write new cachefile");
 421
 422         lockfile_name = NULL;
 423         return has_errors ? 1 : 0;
 424 }