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