update-cache.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7
   8 static int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
   9 {
  10         int len = len1 < len2 ? len1 : len2;
  11         int cmp;
  12
  13         cmp = memcmp(name1, name2, len);
  14         if (cmp)
  15                 return cmp;
  16         if (len1 < len2)
  17                 return -1;
  18         if (len1 > len2)
  19                 return 1;
  20         return 0;
  21 }
  22
  23 static int cache_name_pos(const char *name, int namelen)
  24 {
  25         int first, last;
  26
  27         first = 0;
  28         last = active_nr;
  29         while (last > first) {
  30                 int next = (last + first) >> 1;
  31                 struct cache_entry *ce = active_cache[next];
  32                 int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
  33                 if (!cmp)
  34                         return -next-1;
  35                 if (cmp < 0) {
  36                         last = next;
  37                         continue;
  38                 }
  39                 first = next+1;
  40         }
  41         return first;
  42 }
  43
  44 static int remove_file_from_cache(char *path)
  45 {
  46         int pos = cache_name_pos(path, strlen(path));
  47         if (pos < 0) {
  48                 pos = -pos-1;
  49                 active_nr--;
  50                 if (pos < active_nr)
  51                         memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
  52         }
  53         return 0;
  54 }
  55
  56 static int add_cache_entry(struct cache_entry *ce)
  57 {
  58         int pos;
  59
  60         pos = cache_name_pos(ce->name, ce->namelen);
  61
  62         /* existing match? Just replace it */
  63         if (pos < 0) {
  64                 active_cache[-pos-1] = ce;
  65                 return 0;
  66         }
  67
  68         /* Make sure the array is big enough .. */
  69         if (active_nr == active_alloc) {
  70                 active_alloc = alloc_nr(active_alloc);
  71                 active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
  72         }
  73
  74         /* Add it in.. */
  75         active_nr++;
  76         if (active_nr > pos)
  77                 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
  78         active_cache[pos] = ce;
  79         return 0;
  80 }
  81
  82 static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
  83 {
  84         z_stream stream;
  85         int max_out_bytes = namelen + st->st_size + 200;
  86         void *out = malloc(max_out_bytes);
  87         void *metadata = malloc(namelen + 200);
  88         void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
  89         SHA_CTX c;
  90
  91         close(fd);
  92         if (!out || (int)(long)in == -1)
  93                 return -1;
  94
  95         memset(&stream, 0, sizeof(stream));
  96         deflateInit(&stream, Z_BEST_COMPRESSION);
  97
  98         /*
  99          * ASCII size + nul byte
 100          */
 101         stream.next_in = metadata;
 102         stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
 103         stream.next_out = out;
 104         stream.avail_out = max_out_bytes;
 105         while (deflate(&stream, 0) == Z_OK)
 106                 /* nothing */;
 107
 108         /*
 109          * File content
 110          */
 111         stream.next_in = in;
 112         stream.avail_in = st->st_size;
 113         while (deflate(&stream, Z_FINISH) == Z_OK)
 114                 /*nothing */;
 115
 116         deflateEnd(&stream);
 117
 118         SHA1_Init(&c);
 119         SHA1_Update(&c, out, stream.total_out);
 120         SHA1_Final(ce->sha1, &c);
 121
 122         return write_sha1_buffer(ce->sha1, out, stream.total_out);
 123 }
 124
 125 static int add_file_to_cache(char *path)
 126 {
 127         int size, namelen;
 128         struct cache_entry *ce;
 129         struct stat st;
 130         int fd;
 131
 132         fd = open(path, O_RDONLY);
 133         if (fd < 0) {
 134                 if (errno == ENOENT)
 135                         return remove_file_from_cache(path);
 136                 return -1;
 137         }
 138         if (fstat(fd, &st) < 0) {
 139                 close(fd);
 140                 return -1;
 141         }
 142         namelen = strlen(path);
 143         size = cache_entry_size(namelen);
 144         ce = malloc(size);
 145         memset(ce, 0, size);
 146         memcpy(ce->name, path, namelen);
 147         ce->ctime.sec = st.st_ctime;
 148         ce->ctime.nsec = st.st_ctim.tv_nsec;
 149         ce->mtime.sec = st.st_mtime;
 150         ce->mtime.nsec = st.st_mtim.tv_nsec;
 151         ce->st_dev = st.st_dev;
 152         ce->st_ino = st.st_ino;
 153         ce->st_mode = st.st_mode;
 154         ce->st_uid = st.st_uid;
 155         ce->st_gid = st.st_gid;
 156         ce->st_size = st.st_size;
 157         ce->namelen = namelen;
 158
 159         if (index_fd(path, namelen, ce, fd, &st) < 0)
 160                 return -1;
 161
 162         return add_cache_entry(ce);
 163 }
 164
 165 static int write_cache(int newfd, struct cache_entry **cache, int entries)
 166 {
 167         SHA_CTX c;
 168         struct cache_header hdr;
 169         int i;
 170
 171         hdr.signature = CACHE_SIGNATURE;
 172         hdr.version = 1;
 173         hdr.entries = entries;
 174
 175         SHA1_Init(&c);
 176         SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
 177         for (i = 0; i < entries; i++) {
 178                 struct cache_entry *ce = cache[i];
 179                 int size = ce_size(ce);
 180                 SHA1_Update(&c, ce, size);
 181         }
 182         SHA1_Final(hdr.sha1, &c);
 183
 184         if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
 185                 return -1;
 186
 187         for (i = 0; i < entries; i++) {
 188                 struct cache_entry *ce = cache[i];
 189                 int size = ce_size(ce);
 190                 if (write(newfd, ce, size) != size)
 191                         return -1;
 192         }
 193         return 0;
 194 }
 195
 196 /*
 197  * We fundamentally don't like some paths: we don't want
 198  * dot or dot-dot anywhere, and in fact, we don't even want
 199  * any other dot-files (.dircache or anything else). They
 200  * are hidden, for chist sake.
 201  *
 202  * Also, we don't want double slashes or slashes at the
 203  * end that can make pathnames ambiguous.
 204  */
 205 static int verify_path(char *path)
 206 {
 207         char c;
 208
 209         goto inside;
 210         for (;;) {
 211                 if (!c)
 212                         return 1;
 213                 if (c == '/') {
 214 inside:
 215                         c = *path++;
 216                         if (c != '/' && c != '.' && c != '\0')
 217                                 continue;
 218                         return 0;
 219                 }
 220                 c = *path++;
 221         }
 222 }
 223
 224 int main(int argc, char **argv)
 225 {
 226         int i, newfd, entries;
 227
 228         entries = read_cache();
 229         if (entries < 0) {
 230                 perror("cache corrupted");
 231                 return -1;
 232         }
 233
 234         newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
 235         if (newfd < 0) {
 236                 perror("unable to create new cachefile");
 237                 return -1;
 238         }
 239         for (i = 1 ; i < argc; i++) {
 240                 char *path = argv[i];
 241                 if (!verify_path(path)) {
 242                         fprintf(stderr, "Ignoring path %s\n", argv[i]);
 243                         continue;
 244                 }
 245                 if (add_file_to_cache(path)) {
 246                         fprintf(stderr, "Unable to add %s to database\n", path);
 247                         goto out;
 248                 }
 249         }
 250         if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
 251                 return 0;
 252 out:
 253         unlink(".dircache/index.lock");
 254         return 0;
 255 }