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