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;
  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                 target = xmalloc(st.st_size+1);
  94                 if (readlink(path, target, st.st_size+1) != st.st_size) {
  95                         free(target);
  96                         return -1;
  97                 }
  98                 if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
  99                         return -1;
 100                 free(target);
 101                 break;
 102         default:
 103                 return -1;
 104         }
 105         if (!cache_changed) {
 106                 /* If we have not smudged the cache, be careful
 107                  * to keep it clean.  Find out if we have a matching
 108                  * cache entry that add_cache_entry would replace with,
 109                  * and if it matches then do not bother calling it.
 110                  */
 111                 int pos = cache_name_pos(ce->name, namelen);
 112                 if ((0 <= pos) &&
 113                     !memcmp(active_cache[pos], ce, sizeof(*ce))) {
 114                         free(ce);
 115                         /* magic to tell add_file_to_cache that
 116                          * we have not updated anything.
 117                          */
 118                         return 999;
 119                 }
 120         }
 121         return add_cache_entry(ce, allow_add);
 122 }
 123
 124 static int add_file_to_cache(char *path)
 125 {
 126         int ret = add_file_to_cache_1(path);
 127         if (ret == 0)
 128                 cache_changed = 1;
 129         else if (ret == 999)
 130                 ret = 0;
 131         return ret;
 132 }
 133
 134 static int match_data(int fd, void *buffer, unsigned long size)
 135 {
 136         while (size) {
 137                 char compare[1024];
 138                 int ret = read(fd, compare, sizeof(compare));
 139
 140                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 141                         return -1;
 142                 size -= ret;
 143                 buffer += ret;
 144         }
 145         return 0;
 146 }
 147
 148 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 149 {
 150         int match = -1;
 151         int fd = open(ce->name, O_RDONLY);
 152
 153         if (fd >= 0) {
 154                 void *buffer;
 155                 unsigned long size;
 156                 char type[10];
 157
 158                 buffer = read_sha1_file(ce->sha1, type, &size);
 159                 if (buffer) {
 160                         if (size == expected_size && !strcmp(type, "blob"))
 161                                 match = match_data(fd, buffer, size);
 162                         free(buffer);
 163                 }
 164                 close(fd);
 165         }
 166         return match;
 167 }
 168
 169 static int compare_link(struct cache_entry *ce, unsigned long expected_size)
 170 {
 171         int match = -1;
 172         char *target;
 173         void *buffer;
 174         unsigned long size;
 175         char type[10];
 176         int len;
 177
 178         target = xmalloc(expected_size);
 179         len = readlink(ce->name, target, expected_size);
 180         if (len != expected_size) {
 181                 free(target);
 182                 return -1;
 183         }
 184         buffer = read_sha1_file(ce->sha1, type, &size);
 185         if (!buffer) {
 186                 free(target);
 187                 return -1;
 188         }
 189         if (size == expected_size)
 190                 match = memcmp(buffer, target, size);
 191         free(buffer);
 192         free(target);
 193         return match;
 194 }
 195
 196 /*
 197  * "refresh" does not calculate a new sha1 file or bring the
 198  * cache up-to-date for mode/content changes. But what it
 199  * _does_ do is to "re-match" the stat information of a file
 200  * with the cache, so that you can refresh the cache for a
 201  * file that hasn't been changed but where the stat entry is
 202  * out of date.
 203  *
 204  * For example, you'd want to do this after doing a "read-tree",
 205  * to link up the stat cache details with the proper files.
 206  */
 207 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 208 {
 209         struct stat st;
 210         struct cache_entry *updated;
 211         int changed, size;
 212
 213         if (lstat(ce->name, &st) < 0)
 214                 return ERR_PTR(-errno);
 215
 216         changed = cache_match_stat(ce, &st);
 217         if (!changed)
 218                 return ce;
 219
 220         /*
 221          * If the mode or type has changed, there's no point in trying
 222          * to refresh the entry - it's not going to match
 223          */
 224         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 225                 return ERR_PTR(-EINVAL);
 226
 227         switch (st.st_mode & S_IFMT) {
 228         case S_IFREG:
 229                 if (compare_data(ce, st.st_size))
 230                         return ERR_PTR(-EINVAL);
 231                 break;
 232         case S_IFLNK:
 233                 if (compare_link(ce, st.st_size))
 234                         return ERR_PTR(-EINVAL);
 235                 break;
 236         default:
 237                 return ERR_PTR(-EINVAL);
 238         }
 239
 240         cache_changed = 1;
 241         size = ce_size(ce);
 242         updated = xmalloc(size);
 243         memcpy(updated, ce, size);
 244         fill_stat_cache_info(updated, &st);
 245         return updated;
 246 }
 247
 248 static int refresh_cache(void)
 249 {
 250         int i;
 251         int has_errors = 0;
 252
 253         for (i = 0; i < active_nr; i++) {
 254                 struct cache_entry *ce, *new;
 255                 ce = active_cache[i];
 256                 if (ce_stage(ce)) {
 257                         printf("%s: needs merge\n", ce->name);
 258                         has_errors = 1;
 259                         while ((i < active_nr) &&
 260                                ! strcmp(active_cache[i]->name, ce->name))
 261                                 i++;
 262                         i--;
 263                         continue;
 264                 }
 265
 266                 new = refresh_entry(ce);
 267                 if (IS_ERR(new)) {
 268                         if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 269                                 printf("%s: needs update\n", ce->name);
 270                                 has_errors = 1;
 271                         }
 272                         continue;
 273                 }
 274                 active_cache[i] = new;
 275         }
 276         return has_errors;
 277 }
 278
 279 /*
 280  * We fundamentally don't like some paths: we don't want
 281  * dot or dot-dot anywhere, and in fact, we don't even want
 282  * any other dot-files (.git or anything else). They
 283  * are hidden, for chist sake.
 284  *
 285  * Also, we don't want double slashes or slashes at the
 286  * end that can make pathnames ambiguous.
 287  */
 288 static int verify_path(char *path)
 289 {
 290         char c;
 291
 292         goto inside;
 293         for (;;) {
 294                 if (!c)
 295                         return 1;
 296                 if (c == '/') {
 297 inside:
 298                         c = *path++;
 299                         if (c != '/' && c != '.' && c != '\0')
 300                                 continue;
 301                         return 0;
 302                 }
 303                 c = *path++;
 304         }
 305 }
 306
 307 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 308 {
 309         int size, len;
 310         unsigned int mode;
 311         unsigned char sha1[20];
 312         struct cache_entry *ce;
 313
 314         if (sscanf(arg1, "%o", &mode) != 1)
 315                 return -1;
 316         if (get_sha1_hex(arg2, sha1))
 317                 return -1;
 318         if (!verify_path(arg3))
 319                 return -1;
 320
 321         cache_changed = 1;
 322         len = strlen(arg3);
 323         size = cache_entry_size(len);
 324         ce = xmalloc(size);
 325         memset(ce, 0, size);
 326
 327         memcpy(ce->sha1, sha1, 20);
 328         memcpy(ce->name, arg3, len);
 329         ce->ce_flags = htons(len);
 330         ce->ce_mode = create_ce_mode(mode);
 331         return add_cache_entry(ce, allow_add);
 332 }
 333
 334 static const char *lockfile_name = NULL;
 335
 336 static void remove_lock_file(void)
 337 {
 338         if (lockfile_name)
 339                 unlink(lockfile_name);
 340 }
 341
 342 static void remove_lock_file_on_signal(int signo)
 343 {
 344         remove_lock_file();
 345 }
 346
 347 int main(int argc, char **argv)
 348 {
 349         int i, newfd, entries, has_errors = 0;
 350         int allow_options = 1;
 351         static char lockfile[MAXPATHLEN+1];
 352         const char *indexfile = get_index_file();
 353
 354         snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);
 355
 356         newfd = open(lockfile, O_RDWR | O_CREAT | O_EXCL, 0600);
 357         if (newfd < 0)
 358                 die("unable to create new cachefile");
 359
 360         signal(SIGINT, remove_lock_file_on_signal);
 361         atexit(remove_lock_file);
 362         lockfile_name = lockfile;
 363
 364         entries = read_cache();
 365         if (entries < 0)
 366                 die("cache corrupted");
 367
 368         for (i = 1 ; i < argc; i++) {
 369                 char *path = argv[i];
 370
 371                 if (allow_options && *path == '-') {
 372                         if (!strcmp(path, "--")) {
 373                                 allow_options = 0;
 374                                 continue;
 375                         }
 376                         if (!strcmp(path, "--add")) {
 377                                 allow_add = 1;
 378                                 continue;
 379                         }
 380                         if (!strcmp(path, "--remove")) {
 381                                 allow_remove = 1;
 382                                 continue;
 383                         }
 384                         if (!strcmp(path, "--refresh")) {
 385                                 has_errors |= refresh_cache();
 386                                 continue;
 387                         }
 388                         if (!strcmp(path, "--cacheinfo")) {
 389                                 if (i+3 >= argc || add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 390                                         die("update-cache: --cacheinfo <mode> <sha1> <path>");
 391                                 i += 3;
 392                                 continue;
 393                         }
 394                         if (!strcmp(path, "--force-remove")) {
 395                                 if (argc <= i + 1)
 396                                         die("update-cache: --force-remove <path>");
 397                                 if (remove_file_from_cache(argv[i+1]))
 398                                         die("update-cache: --force-remove cannot remove %s", argv[i+1]);
 399                                 i++;
 400                                 continue;
 401                         }
 402
 403                         if (!strcmp(path, "--ignore-missing")) {
 404                                 not_new = 1;
 405                                 continue;
 406                         }
 407                         die("unknown option %s", path);
 408                 }
 409                 if (!verify_path(path)) {
 410                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 411                         continue;
 412                 }
 413                 if (add_file_to_cache(path))
 414                         die("Unable to add %s to database", path);
 415         }
 416
 417         if (!cache_changed)
 418                 unlink(lockfile);
 419         else if (write_cache(newfd, active_cache, active_nr) ||
 420                  rename(lockfile, indexfile))
 421                 die("Unable to write new cachefile");
 422
 423         lockfile_name = NULL;
 424         return has_errors ? 1 : 0;
 425 }