update-cache.c

   1 #include "cache.h"
   2
   3 static int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
   4 {
   5         int len = len1 < len2 ? len1 : len2;
   6         int cmp;
   7
   8         cmp = memcmp(name1, name2, len);
   9         if (cmp)
  10                 return cmp;
  11         if (len1 < len2)
  12                 return -1;
  13         if (len1 > len2)
  14                 return 1;
  15         return 0;
  16 }
  17
  18 static int cache_name_pos(const char *name, int namelen)
  19 {
  20         int first, last;
  21
  22         first = 0;
  23         last = active_nr;
  24         while (last > first) {
  25                 int next = (last + first) >> 1;
  26                 struct cache_entry *ce = active_cache[next];
  27                 int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
  28                 if (!cmp)
  29                         return -next-1;
  30                 if (cmp < 0) {
  31                         last = next;
  32                         continue;
  33                 }
  34                 first = next+1;
  35         }
  36         return first;
  37 }
  38
  39 static int remove_file_from_cache(char *path)
  40 {
  41         int pos = cache_name_pos(path, strlen(path));
  42         if (pos < 0) {
  43                 pos = -pos-1;
  44                 active_nr--;
  45                 if (pos < active_nr)
  46                         memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
  47         }
  48 }
  49
  50 static int add_cache_entry(struct cache_entry *ce)
  51 {
  52         int pos;
  53
  54         pos = cache_name_pos(ce->name, ce->namelen);
  55
  56         /* existing match? Just replace it */
  57         if (pos < 0) {
  58                 active_cache[-pos-1] = ce;
  59                 return 0;
  60         }
  61
  62         /* Make sure the array is big enough .. */
  63         if (active_nr == active_alloc) {
  64                 active_alloc = alloc_nr(active_alloc);
  65                 active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
  66         }
  67
  68         /* Add it in.. */
  69         active_nr++;
  70         if (active_nr > pos)
  71                 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
  72         active_cache[pos] = ce;
  73         return 0;
  74 }
  75
  76 static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
  77 {
  78         z_stream stream;
  79         int max_out_bytes = namelen + st->st_size + 200;
  80         void *out = malloc(max_out_bytes);
  81         void *metadata = malloc(namelen + 200);
  82         void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  83         SHA_CTX c;
  84
  85         close(fd);
  86         if (!out || (int)(long)in == -1)
  87                 return -1;
  88
  89         memset(&stream, 0, sizeof(stream));
  90         deflateInit(&stream, Z_BEST_COMPRESSION);
  91
  92         /*
  93          * ASCII size + nul byte
  94          */
  95         stream.next_in = metadata;
  96         stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
  97         stream.next_out = out;
  98         stream.avail_out = max_out_bytes;
  99         while (deflate(&stream, 0) == Z_OK)
 100                 /* nothing */;
 101
 102         /*
 103          * File content
 104          */
 105         stream.next_in = in;
 106         stream.avail_in = st->st_size;
 107         while (deflate(&stream, Z_FINISH) == Z_OK)
 108                 /*nothing */;
 109
 110         deflateEnd(&stream);
 111
 112         SHA1_Init(&c);
 113         SHA1_Update(&c, out, stream.total_out);
 114         SHA1_Final(ce->sha1, &c);
 115
 116         return write_sha1_buffer(ce->sha1, out, stream.total_out);
 117 }
 118
 119 static int add_file_to_cache(char *path)
 120 {
 121         int size, namelen;
 122         struct cache_entry *ce;
 123         struct stat st;
 124         int fd;
 125
 126         fd = open(path, O_RDONLY);
 127         if (fd < 0) {
 128                 if (errno == ENOENT)
 129                         return remove_file_from_cache(path);
 130                 return -1;
 131         }
 132         if (fstat(fd, &st) < 0) {
 133                 close(fd);
 134                 return -1;
 135         }
 136         namelen = strlen(path);
 137         size = cache_entry_size(namelen);
 138         ce = malloc(size);
 139         memset(ce, 0, size);
 140         memcpy(ce->name, path, namelen);
 141         ce->ctime.sec = st.st_ctime;
 142         ce->ctime.nsec = st.st_ctim.tv_nsec;
 143         ce->mtime.sec = st.st_mtime;
 144         ce->mtime.nsec = st.st_mtim.tv_nsec;
 145         ce->st_dev = st.st_dev;
 146         ce->st_ino = st.st_ino;
 147         ce->st_mode = st.st_mode;
 148         ce->st_uid = st.st_uid;
 149         ce->st_gid = st.st_gid;
 150         ce->st_size = st.st_size;
 151         ce->namelen = namelen;
 152
 153         if (index_fd(path, namelen, ce, fd, &st) < 0)
 154                 return -1;
 155
 156         return add_cache_entry(ce);
 157 }
 158
 159 static int write_cache(int newfd, struct cache_entry **cache, int entries)
 160 {
 161         SHA_CTX c;
 162         struct cache_header hdr;
 163         int i;
 164
 165         hdr.signature = CACHE_SIGNATURE;
 166         hdr.version = 1;
 167         hdr.entries = entries;
 168
 169         SHA1_Init(&c);
 170         SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
 171         for (i = 0; i < entries; i++) {
 172                 struct cache_entry *ce = cache[i];
 173                 int size = ce_size(ce);
 174                 SHA1_Update(&c, ce, size);
 175         }
 176         SHA1_Final(hdr.sha1, &c);
 177
 178         if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
 179                 return -1;
 180
 181         for (i = 0; i < entries; i++) {
 182                 struct cache_entry *ce = cache[i];
 183                 int size = ce_size(ce);
 184                 if (write(newfd, ce, size) != size)
 185                         return -1;
 186         }
 187         return 0;
 188 }
 189
 190 /*
 191  * We fundamentally don't like some paths: we don't want
 192  * dot or dot-dot anywhere, and in fact, we don't even want
 193  * any other dot-files (.dircache or anything else). They
 194  * are hidden, for chist sake.
 195  *
 196  * Also, we don't want double slashes or slashes at the
 197  * end that can make pathnames ambiguous.
 198  */
 199 static int verify_path(char *path)
 200 {
 201         char c;
 202
 203         goto inside;
 204         for (;;) {
 205                 if (!c)
 206                         return 1;
 207                 if (c == '/') {
 208 inside:
 209                         c = *path++;
 210                         if (c != '/' && c != '.' && c != '\0')
 211                                 continue;
 212                         return 0;
 213                 }
 214                 c = *path++;
 215         }
 216 }
 217
 218 int main(int argc, char **argv)
 219 {
 220         int i, newfd, entries;
 221
 222         entries = read_cache();
 223         if (entries < 0) {
 224                 perror("cache corrupted");
 225                 return -1;
 226         }
 227
 228         newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
 229         if (newfd < 0) {
 230                 perror("unable to create new cachefile");
 231                 return -1;
 232         }
 233         for (i = 1 ; i < argc; i++) {
 234                 char *path = argv[i];
 235                 if (!verify_path(path)) {
 236                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 237                         continue;
 238                 }
 239                 if (add_file_to_cache(path)) {
 240                         fprintf(stderr, "Unable to add %s to database\n", path);
 241                         goto out;
 242                 }
 243         }
 244         if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
 245                 return 0;
 246 out:
 247         unlink(".dircache/index.lock");
 248 }