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, allow_replace = 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, option, status;
  57         struct cache_entry *ce;
  58         struct stat st;
  59         int fd;
  60         char *target;
  61
  62         status = lstat(path, &st);
  63         if (status < 0 || S_ISDIR(st.st_mode)) {
  64                 /* When we used to have "path" and now we want to add
  65                  * "path/file", we need a way to remove "path" before
  66                  * being able to add "path/file".  However,
  67                  * "git-update-cache --remove path" would not work.
  68                  * --force-remove can be used but this is more user
  69                  * friendly, especially since we can do the opposite
  70                  * case just fine without --force-remove.
  71                  */
  72                 if (status == 0 || (errno == ENOENT || errno == ENOTDIR)) {
  73                         if (allow_remove)
  74                                 return remove_file_from_cache(path);
  75                 }
  76                 return error("open(\"%s\"): %s", path, strerror(errno));
  77         }
  78         namelen = strlen(path);
  79         size = cache_entry_size(namelen);
  80         ce = xmalloc(size);
  81         memset(ce, 0, size);
  82         memcpy(ce->name, path, namelen);
  83         fill_stat_cache_info(ce, &st);
  84         ce->ce_mode = create_ce_mode(st.st_mode);
  85         ce->ce_flags = htons(namelen);
  86         switch (st.st_mode & S_IFMT) {
  87         case S_IFREG:
  88                 fd = open(path, O_RDONLY);
  89                 if (fd < 0)
  90                         return -1;
  91                 if (index_fd(ce->sha1, fd, &st) < 0)
  92                         return -1;
  93                 break;
  94         case S_IFLNK:
  95                 target = xmalloc(st.st_size+1);
  96                 if (readlink(path, target, st.st_size+1) != st.st_size) {
  97                         free(target);
  98                         return -1;
  99                 }
 100                 if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
 101                         return -1;
 102                 free(target);
 103                 break;
 104         default:
 105                 return -1;
 106         }
 107         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
 108         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
 109         return add_cache_entry(ce, option);
 110 }
 111
 112 static int match_data(int fd, void *buffer, unsigned long size)
 113 {
 114         while (size) {
 115                 char compare[1024];
 116                 int ret = read(fd, compare, sizeof(compare));
 117
 118                 if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 119                         return -1;
 120                 size -= ret;
 121                 buffer += ret;
 122         }
 123         return 0;
 124 }
 125
 126 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 127 {
 128         int match = -1;
 129         int fd = open(ce->name, O_RDONLY);
 130
 131         if (fd >= 0) {
 132                 void *buffer;
 133                 unsigned long size;
 134                 char type[20];
 135
 136                 buffer = read_sha1_file(ce->sha1, type, &size);
 137                 if (buffer) {
 138                         if (size == expected_size && !strcmp(type, "blob"))
 139                                 match = match_data(fd, buffer, size);
 140                         free(buffer);
 141                 }
 142                 close(fd);
 143         }
 144         return match;
 145 }
 146
 147 static int compare_link(struct cache_entry *ce, unsigned long expected_size)
 148 {
 149         int match = -1;
 150         char *target;
 151         void *buffer;
 152         unsigned long size;
 153         char type[10];
 154         int len;
 155
 156         target = xmalloc(expected_size);
 157         len = readlink(ce->name, target, expected_size);
 158         if (len != expected_size) {
 159                 free(target);
 160                 return -1;
 161         }
 162         buffer = read_sha1_file(ce->sha1, type, &size);
 163         if (!buffer) {
 164                 free(target);
 165                 return -1;
 166         }
 167         if (size == expected_size)
 168                 match = memcmp(buffer, target, size);
 169         free(buffer);
 170         free(target);
 171         return match;
 172 }
 173
 174 /*
 175  * "refresh" does not calculate a new sha1 file or bring the
 176  * cache up-to-date for mode/content changes. But what it
 177  * _does_ do is to "re-match" the stat information of a file
 178  * with the cache, so that you can refresh the cache for a
 179  * file that hasn't been changed but where the stat entry is
 180  * out of date.
 181  *
 182  * For example, you'd want to do this after doing a "read-tree",
 183  * to link up the stat cache details with the proper files.
 184  */
 185 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 186 {
 187         struct stat st;
 188         struct cache_entry *updated;
 189         int changed, size;
 190
 191         if (lstat(ce->name, &st) < 0)
 192                 return ERR_PTR(-errno);
 193
 194         changed = cache_match_stat(ce, &st);
 195         if (!changed)
 196                 return ce;
 197
 198         /*
 199          * If the mode or type has changed, there's no point in trying
 200          * to refresh the entry - it's not going to match
 201          */
 202         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 203                 return ERR_PTR(-EINVAL);
 204
 205         switch (st.st_mode & S_IFMT) {
 206         case S_IFREG:
 207                 if (compare_data(ce, st.st_size))
 208                         return ERR_PTR(-EINVAL);
 209                 break;
 210         case S_IFLNK:
 211                 if (compare_link(ce, st.st_size))
 212                         return ERR_PTR(-EINVAL);
 213                 break;
 214         default:
 215                 return ERR_PTR(-EINVAL);
 216         }
 217
 218         size = ce_size(ce);
 219         updated = xmalloc(size);
 220         memcpy(updated, ce, size);
 221         fill_stat_cache_info(updated, &st);
 222         return updated;
 223 }
 224
 225 static int refresh_cache(void)
 226 {
 227         int i;
 228         int has_errors = 0;
 229
 230         for (i = 0; i < active_nr; i++) {
 231                 struct cache_entry *ce, *new;
 232                 ce = active_cache[i];
 233                 if (ce_stage(ce)) {
 234                         printf("%s: needs merge\n", ce->name);
 235                         has_errors = 1;
 236                         while ((i < active_nr) &&
 237                                ! strcmp(active_cache[i]->name, ce->name))
 238                                 i++;
 239                         i--;
 240                         continue;
 241                 }
 242
 243                 new = refresh_entry(ce);
 244                 if (IS_ERR(new)) {
 245                         if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 246                                 printf("%s: needs update\n", ce->name);
 247                                 has_errors = 1;
 248                         }
 249                         continue;
 250                 }
 251                 active_cache_changed = 1;
 252                 /* You can NOT just free active_cache[i] here, since it
 253                  * might not be necessarily malloc()ed but can also come
 254                  * from mmap(). */
 255                 active_cache[i] = new;
 256         }
 257         return has_errors;
 258 }
 259
 260 /*
 261  * We fundamentally don't like some paths: we don't want
 262  * dot or dot-dot anywhere, and in fact, we don't even want
 263  * any other dot-files (.git or anything else). They
 264  * are hidden, for chist sake.
 265  *
 266  * Also, we don't want double slashes or slashes at the
 267  * end that can make pathnames ambiguous.
 268  */
 269 static int verify_path(char *path)
 270 {
 271         char c;
 272
 273         goto inside;
 274         for (;;) {
 275                 if (!c)
 276                         return 1;
 277                 if (c == '/') {
 278 inside:
 279                         c = *path++;
 280                         if (c != '/' && c != '.' && c != '\0')
 281                                 continue;
 282                         return 0;
 283                 }
 284                 c = *path++;
 285         }
 286 }
 287
 288 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 289 {
 290         int size, len, option;
 291         unsigned int mode;
 292         unsigned char sha1[20];
 293         struct cache_entry *ce;
 294
 295         if (sscanf(arg1, "%o", &mode) != 1)
 296                 return -1;
 297         if (get_sha1_hex(arg2, sha1))
 298                 return -1;
 299         if (!verify_path(arg3))
 300                 return -1;
 301
 302         len = strlen(arg3);
 303         size = cache_entry_size(len);
 304         ce = xmalloc(size);
 305         memset(ce, 0, size);
 306
 307         memcpy(ce->sha1, sha1, 20);
 308         memcpy(ce->name, arg3, len);
 309         ce->ce_flags = htons(len);
 310         ce->ce_mode = create_ce_mode(mode);
 311         option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
 312         option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
 313         return add_cache_entry(ce, option);
 314 }
 315
 316 static const char *lockfile_name = NULL;
 317
 318 static void remove_lock_file(void)
 319 {
 320         if (lockfile_name)
 321                 unlink(lockfile_name);
 322 }
 323
 324 static void remove_lock_file_on_signal(int signo)
 325 {
 326         remove_lock_file();
 327 }
 328
 329 int main(int argc, char **argv)
 330 {
 331         int i, newfd, entries, has_errors = 0;
 332         int allow_options = 1;
 333         static char lockfile[MAXPATHLEN+1];
 334         const char *indexfile = get_index_file();
 335
 336         snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);
 337
 338         newfd = open(lockfile, O_RDWR | O_CREAT | O_EXCL, 0600);
 339         if (newfd < 0)
 340                 die("unable to create new cachefile");
 341
 342         signal(SIGINT, remove_lock_file_on_signal);
 343         atexit(remove_lock_file);
 344         lockfile_name = lockfile;
 345
 346         entries = read_cache();
 347         if (entries < 0)
 348                 die("cache corrupted");
 349
 350         for (i = 1 ; i < argc; i++) {
 351                 char *path = argv[i];
 352
 353                 if (allow_options && *path == '-') {
 354                         if (!strcmp(path, "--")) {
 355                                 allow_options = 0;
 356                                 continue;
 357                         }
 358                         if (!strcmp(path, "--add")) {
 359                                 allow_add = 1;
 360                                 continue;
 361                         }
 362                         if (!strcmp(path, "--replace")) {
 363                                 allow_replace = 1;
 364                                 continue;
 365                         }
 366                         if (!strcmp(path, "--remove")) {
 367                                 allow_remove = 1;
 368                                 continue;
 369                         }
 370                         if (!strcmp(path, "--refresh")) {
 371                                 has_errors |= refresh_cache();
 372                                 continue;
 373                         }
 374                         if (!strcmp(path, "--cacheinfo")) {
 375                                 if (i+3 >= argc)
 376                                         die("update-cache: --cacheinfo <mode> <sha1> <path>");
 377                                 if (add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 378                                         die("update-cache: --cacheinfo cannot add %s", argv[i+3]);
 379                                 i += 3;
 380                                 continue;
 381                         }
 382                         if (!strcmp(path, "--force-remove")) {
 383                                 if (argc <= i + 1)
 384                                         die("update-cache: --force-remove <path>");
 385                                 if (remove_file_from_cache(argv[i+1]))
 386                                         die("update-cache: --force-remove cannot remove %s", argv[i+1]);
 387                                 i++;
 388                                 continue;
 389                         }
 390
 391                         if (!strcmp(path, "--ignore-missing")) {
 392                                 not_new = 1;
 393                                 continue;
 394                         }
 395                         die("unknown option %s", path);
 396                 }
 397                 if (!verify_path(path)) {
 398                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 399                         continue;
 400                 }
 401                 if (add_file_to_cache(path))
 402                         die("Unable to add %s to database", path);
 403         }
 404         if (write_cache(newfd, active_cache, active_nr) || rename(lockfile, indexfile))
 405                 die("Unable to write new cachefile");
 406
 407         lockfile_name = NULL;
 408         return has_errors ? 1 : 0;
 409 }