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