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