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         unsigned int len;
  67         char target[1024];
  68
  69         if (lstat(path, &st) < 0) {
  70                 if (errno == ENOENT || errno == ENOTDIR) {
  71                         if (allow_remove)
  72                                 return remove_file_from_cache(path);
  73                 }
  74                 return -1;
  75         }
  76         namelen = strlen(path);
  77         size = cache_entry_size(namelen);
  78         ce = xmalloc(size);
  79         memset(ce, 0, size);
  80         memcpy(ce->name, path, namelen);
  81         fill_stat_cache_info(ce, &st);
  82         ce->ce_mode = create_ce_mode(st.st_mode);
  83         ce->ce_flags = htons(namelen);
  84         switch (st.st_mode & S_IFMT) {
  85         case S_IFREG:
  86                 fd = open(path, O_RDONLY);
  87                 if (fd < 0)
  88                         return -1;
  89                 if (index_fd(ce->sha1, fd, &st) < 0)
  90                         return -1;
  91                 break;
  92         case S_IFLNK:
  93                 len = readlink(path, target, sizeof(target));
  94                 if (len == -1 || len+1 > sizeof(target))
  95                         return -1;
  96                 if (write_sha1_file(target, len, "blob", ce->sha1))
  97                         return -1;
  98                 break;
  99         default:
 100                 return -1;
 101         }
 102         if (!cache_changed) {
 103                 /* If we have not smudged the cache, be careful
 104                  * to keep it clean.  Find out if we have a matching
 105                  * cache entry that add_cache_entry would replace with,
 106                  * and if it matches then do not bother calling it.
 107                  */
 108                 int pos = cache_name_pos(ce->name, namelen);
 109                 if ((0 <= pos) &&
 110                     !memcmp(active_cache[pos], ce, sizeof(*ce))) {
 111                         free(ce);
 112                         /* magic to tell add_file_to_cache that
 113                          * we have not updated anything.
 114                          */
 115                         return 999;
 116                 }
 117         }
 118         return add_cache_entry(ce, allow_add);
 119 }
 120
 121 static int add_file_to_cache(char *path)
 122 {
 123         int ret = add_file_to_cache_1(path);
 124         if (ret == 0)
 125                 cache_changed = 1;
 126         else if (ret == 999)
 127                 ret = 0;
 128         return ret;
 129 }
 130
 131 static int match_data(int fd, void *buffer, unsigned long size)
 132 {
 133         while (size) {
 134                 char compare[1024];
 135                 int ret = read(fd, compare, sizeof(compare));
 136
 137                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 138                         return -1;
 139                 size -= ret;
 140                 buffer += ret;
 141         }
 142         return 0;
 143 }
 144
 145 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 146 {
 147         int match = -1;
 148         int fd = open(ce->name, O_RDONLY);
 149
 150         if (fd >= 0) {
 151                 void *buffer;
 152                 unsigned long size;
 153                 char type[10];
 154
 155                 buffer = read_sha1_file(ce->sha1, type, &size);
 156                 if (buffer) {
 157                         if (size == expected_size && !strcmp(type, "blob"))
 158                                 match = match_data(fd, buffer, size);
 159                         free(buffer);
 160                 }
 161                 close(fd);
 162         }
 163         return match;
 164 }
 165
 166 /*
 167  * "refresh" does not calculate a new sha1 file or bring the
 168  * cache up-to-date for mode/content changes. But what it
 169  * _does_ do is to "re-match" the stat information of a file
 170  * with the cache, so that you can refresh the cache for a
 171  * file that hasn't been changed but where the stat entry is
 172  * out of date.
 173  *
 174  * For example, you'd want to do this after doing a "read-tree",
 175  * to link up the stat cache details with the proper files.
 176  */
 177 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 178 {
 179         struct stat st;
 180         struct cache_entry *updated;
 181         int changed, size;
 182
 183         if (lstat(ce->name, &st) < 0)
 184                 return ERR_PTR(-errno);
 185
 186         changed = cache_match_stat(ce, &st);
 187         if (!changed)
 188                 return ce;
 189
 190         /*
 191          * If the mode or type has changed, there's no point in trying
 192          * to refresh the entry - it's not going to match
 193          */
 194         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 195                 return ERR_PTR(-EINVAL);
 196
 197         if (compare_data(ce, st.st_size))
 198                 return ERR_PTR(-EINVAL);
 199
 200         cache_changed = 1;
 201         size = ce_size(ce);
 202         updated = xmalloc(size);
 203         memcpy(updated, ce, size);
 204         fill_stat_cache_info(updated, &st);
 205         return updated;
 206 }
 207
 208 static int refresh_cache(void)
 209 {
 210         int i;
 211         int has_errors = 0;
 212
 213         for (i = 0; i < active_nr; i++) {
 214                 struct cache_entry *ce, *new;
 215                 ce = active_cache[i];
 216                 if (ce_stage(ce)) {
 217                         printf("%s: needs merge\n", ce->name);
 218                         has_errors = 1;
 219                         while ((i < active_nr) &&
 220                                ! strcmp(active_cache[i]->name, ce->name))
 221                                 i++;
 222                         i--;
 223                         continue;
 224                 }
 225
 226                 new = refresh_entry(ce);
 227                 if (IS_ERR(new)) {
 228                         if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 229                                 printf("%s: needs update\n", ce->name);
 230                                 has_errors = 1;
 231                         }
 232                         continue;
 233                 }
 234                 active_cache[i] = new;
 235         }
 236         return has_errors;
 237 }
 238
 239 /*
 240  * We fundamentally don't like some paths: we don't want
 241  * dot or dot-dot anywhere, and in fact, we don't even want
 242  * any other dot-files (.git or anything else). They
 243  * are hidden, for chist sake.
 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_path(char *path)
 249 {
 250         char c;
 251
 252         goto inside;
 253         for (;;) {
 254                 if (!c)
 255                         return 1;
 256                 if (c == '/') {
 257 inside:
 258                         c = *path++;
 259                         if (c != '/' && c != '.' && c != '\0')
 260                                 continue;
 261                         return 0;
 262                 }
 263                 c = *path++;
 264         }
 265 }
 266
 267 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 268 {
 269         int size, len;
 270         unsigned int mode;
 271         unsigned char sha1[20];
 272         struct cache_entry *ce;
 273
 274         if (sscanf(arg1, "%o", &mode) != 1)
 275                 return -1;
 276         if (get_sha1_hex(arg2, sha1))
 277                 return -1;
 278         if (!verify_path(arg3))
 279                 return -1;
 280
 281         cache_changed = 1;
 282         len = strlen(arg3);
 283         size = cache_entry_size(len);
 284         ce = xmalloc(size);
 285         memset(ce, 0, size);
 286
 287         memcpy(ce->sha1, sha1, 20);
 288         memcpy(ce->name, arg3, len);
 289         ce->ce_flags = htons(len);
 290         ce->ce_mode = create_ce_mode(mode);
 291         return add_cache_entry(ce, allow_add);
 292 }
 293
 294 static const char *lockfile_name = NULL;
 295
 296 static void remove_lock_file(void)
 297 {
 298         if (lockfile_name)
 299                 unlink(lockfile_name);
 300 }
 301
 302 static void remove_lock_file_on_signal(int signo)
 303 {
 304         remove_lock_file();
 305 }
 306
 307 int main(int argc, char **argv)
 308 {
 309         int i, newfd, entries, has_errors = 0;
 310         int allow_options = 1;
 311         static char lockfile[MAXPATHLEN+1];
 312         const char *indexfile = get_index_file();
 313
 314         snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);
 315
 316         newfd = open(lockfile, O_RDWR | O_CREAT | O_EXCL, 0600);
 317         if (newfd < 0)
 318                 die("unable to create new cachefile");
 319
 320         signal(SIGINT, remove_lock_file_on_signal);
 321         atexit(remove_lock_file);
 322         lockfile_name = lockfile;
 323
 324         entries = read_cache();
 325         if (entries < 0)
 326                 die("cache corrupted");
 327
 328         for (i = 1 ; i < argc; i++) {
 329                 char *path = argv[i];
 330
 331                 if (allow_options && *path == '-') {
 332                         if (!strcmp(path, "--")) {
 333                                 allow_options = 0;
 334                                 continue;
 335                         }
 336                         if (!strcmp(path, "--add")) {
 337                                 allow_add = 1;
 338                                 continue;
 339                         }
 340                         if (!strcmp(path, "--remove")) {
 341                                 allow_remove = 1;
 342                                 continue;
 343                         }
 344                         if (!strcmp(path, "--refresh")) {
 345                                 has_errors |= refresh_cache();
 346                                 continue;
 347                         }
 348                         if (!strcmp(path, "--cacheinfo")) {
 349                                 if (i+3 >= argc || add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 350                                         die("update-cache: --cacheinfo <mode> <sha1> <path>");
 351                                 i += 3;
 352                                 continue;
 353                         }
 354                         if (!strcmp(path, "--force-remove")) {
 355                                 if (argc <= i + 1)
 356                                         die("update-cache: --force-remove <path>");
 357                                 if (remove_file_from_cache(argv[i+1]))
 358                                         die("update-cache: --force-remove cannot remove %s", argv[i+1]);
 359                                 i++;
 360                                 continue;
 361                         }
 362
 363                         if (!strcmp(path, "--ignore-missing")) {
 364                                 not_new = 1;
 365                                 continue;
 366                         }
 367                         die("unknown option %s", path);
 368                 }
 369                 if (!verify_path(path)) {
 370                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 371                         continue;
 372                 }
 373                 if (add_file_to_cache(path))
 374                         die("Unable to add %s to database", path);
 375         }
 376
 377         if (!cache_changed)
 378                 unlink(lockfile);
 379         else if (write_cache(newfd, active_cache, active_nr) ||
 380                  rename(lockfile, indexfile))
 381                 die("Unable to write new cachefile");
 382
 383         lockfile_name = NULL;
 384         return has_errors ? 1 : 0;
 385 }