Andrew's git - gitweb.git/blob

91b2628e3c18e7f75e477c24197d9ef2eca14125
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6#include "cache.h"
   7
   8const char *sha1_file_directory = NULL;
   9struct cache_entry **active_cache = NULL;
  10unsigned int active_nr = 0, active_alloc = 0;
  11
  12void usage(const char *err)
  13{
  14        fprintf(stderr, "read-tree: %s\n", err);
  15        exit(1);
  16}
  17
  18static unsigned hexval(char c)
  19{
  20        if (c >= '0' && c <= '9')
  21                return c - '0';
  22        if (c >= 'a' && c <= 'f')
  23                return c - 'a' + 10;
  24        if (c >= 'A' && c <= 'F')
  25                return c - 'A' + 10;
  26        return ~0;
  27}
  28
  29int get_sha1_hex(const char *hex, unsigned char *sha1)
  30{
  31        int i;
  32        for (i = 0; i < 20; i++) {
  33                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  34                if (val & ~0xff)
  35                        return -1;
  36                *sha1++ = val;
  37                hex += 2;
  38        }
  39        return 0;
  40}
  41
  42char * sha1_to_hex(const unsigned char *sha1)
  43{
  44        static char buffer[50];
  45        static const char hex[] = "0123456789abcdef";
  46        char *buf = buffer;
  47        int i;
  48
  49        for (i = 0; i < 20; i++) {
  50                unsigned int val = *sha1++;
  51                *buf++ = hex[val >> 4];
  52                *buf++ = hex[val & 0xf];
  53        }
  54        return buffer;
  55}
  56
  57/*
  58 * NOTE! This returns a statically allocated buffer, so you have to be
  59 * careful about using it. Do a "strdup()" if you need to save the
  60 * filename.
  61 */
  62char *sha1_file_name(unsigned char *sha1)
  63{
  64        int i;
  65        static char *name, *base;
  66
  67        if (!base) {
  68                char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
  69                int len = strlen(sha1_file_directory);
  70                base = malloc(len + 60);
  71                memcpy(base, sha1_file_directory, len);
  72                memset(base+len, 0, 60);
  73                base[len] = '/';
  74                base[len+3] = '/';
  75                name = base + len + 1;
  76        }
  77        for (i = 0; i < 20; i++) {
  78                static char hex[] = "0123456789abcdef";
  79                unsigned int val = sha1[i];
  80                char *pos = name + i*2 + (i > 0);
  81                *pos++ = hex[val >> 4];
  82                *pos = hex[val & 0xf];
  83        }
  84        return base;
  85}
  86
  87int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
  88{
  89        unsigned char real_sha1[20];
  90        SHA_CTX c;
  91
  92        SHA1_Init(&c);
  93        SHA1_Update(&c, map, size);
  94        SHA1_Final(real_sha1, &c);
  95        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
  96}
  97
  98void *map_sha1_file(unsigned char *sha1, unsigned long *size)
  99{
 100        char *filename = sha1_file_name(sha1);
 101        int fd = open(filename, O_RDONLY);
 102        struct stat st;
 103        void *map;
 104
 105        if (fd < 0) {
 106                perror(filename);
 107                return NULL;
 108        }
 109        if (fstat(fd, &st) < 0) {
 110                close(fd);  
 111                return NULL;
 112        }
 113        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 114        close(fd);
 115        if (-1 == (int)(long)map)
 116                return NULL;
 117        *size = st.st_size;
 118        return map;
 119}
 120
 121void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 122{
 123        int ret, bytes;
 124        z_stream stream;
 125        char buffer[8192];
 126        char *buf;
 127
 128        /* Get the data stream */
 129        memset(&stream, 0, sizeof(stream));
 130        stream.next_in = map;
 131        stream.avail_in = mapsize;
 132        stream.next_out = buffer;
 133        stream.avail_out = sizeof(buffer);
 134
 135        inflateInit(&stream);
 136        ret = inflate(&stream, 0);
 137        if (sscanf(buffer, "%10s %lu", type, size) != 2)
 138                return NULL;
 139
 140        bytes = strlen(buffer) + 1;
 141        buf = malloc(*size);
 142        if (!buf)
 143                return NULL;
 144
 145        memcpy(buf, buffer + bytes, stream.total_out - bytes);
 146        bytes = stream.total_out - bytes;
 147        if (bytes < *size && ret == Z_OK) {
 148                stream.next_out = buf + bytes;
 149                stream.avail_out = *size - bytes;
 150                while (inflate(&stream, Z_FINISH) == Z_OK)
 151                        /* nothing */;
 152        }
 153        inflateEnd(&stream);
 154        return buf;
 155}
 156
 157void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
 158{
 159        unsigned long mapsize;
 160        void *map, *buf;
 161
 162        map = map_sha1_file(sha1, &mapsize);
 163        if (map) {
 164                buf = unpack_sha1_file(map, mapsize, type, size);
 165                munmap(map, mapsize);
 166                return buf;
 167        }
 168        return NULL;
 169}
 170
 171int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 172{
 173        int size;
 174        char *compressed;
 175        z_stream stream;
 176        unsigned char sha1[20];
 177        SHA_CTX c;
 178
 179        /* Set it up */
 180        memset(&stream, 0, sizeof(stream));
 181        deflateInit(&stream, Z_BEST_COMPRESSION);
 182        size = deflateBound(&stream, len);
 183        compressed = malloc(size);
 184
 185        /* Compress it */
 186        stream.next_in = buf;
 187        stream.avail_in = len;
 188        stream.next_out = compressed;
 189        stream.avail_out = size;
 190        while (deflate(&stream, Z_FINISH) == Z_OK)
 191                /* nothing */;
 192        deflateEnd(&stream);
 193        size = stream.total_out;
 194
 195        /* Sha1.. */
 196        SHA1_Init(&c);
 197        SHA1_Update(&c, compressed, size);
 198        SHA1_Final(sha1, &c);
 199
 200        if (write_sha1_buffer(sha1, compressed, size) < 0)
 201                return -1;
 202        if (returnsha1)
 203                memcpy(returnsha1, sha1, 20);
 204        return 0;
 205}
 206
 207int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
 208{
 209        char *filename = sha1_file_name(sha1);
 210        int fd;
 211
 212        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 213        if (fd < 0)
 214                return (errno == EEXIST) ? 0 : -1;
 215        write(fd, buf, size);
 216        close(fd);
 217        return 0;
 218}
 219
 220static int error(const char * string)
 221{
 222        fprintf(stderr, "error: %s\n", string);
 223        return -1;
 224}
 225
 226int cache_match_stat(struct cache_entry *ce, struct stat *st)
 227{
 228        unsigned int changed = 0;
 229
 230        if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec ||
 231            ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
 232                changed |= MTIME_CHANGED;
 233        if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec ||
 234            ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
 235                changed |= CTIME_CHANGED;
 236        if (ce->st_uid != (unsigned int)st->st_uid ||
 237            ce->st_gid != (unsigned int)st->st_gid)
 238                changed |= OWNER_CHANGED;
 239        if (ce->st_mode != (unsigned int)st->st_mode)
 240                changed |= MODE_CHANGED;
 241        if (ce->st_dev != (unsigned int)st->st_dev ||
 242            ce->st_ino != (unsigned int)st->st_ino)
 243                changed |= INODE_CHANGED;
 244        if (ce->st_size != (unsigned int)st->st_size)
 245                changed |= DATA_CHANGED;
 246        return changed;
 247}
 248
 249int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
 250{
 251        int len = len1 < len2 ? len1 : len2;
 252        int cmp;
 253
 254        cmp = memcmp(name1, name2, len);
 255        if (cmp)
 256                return cmp;
 257        if (len1 < len2)
 258                return -1;
 259        if (len1 > len2)
 260                return 1;
 261        return 0;
 262}
 263
 264int cache_name_pos(const char *name, int namelen)
 265{
 266        int first, last;
 267
 268        first = 0;
 269        last = active_nr;
 270        while (last > first) {
 271                int next = (last + first) >> 1;
 272                struct cache_entry *ce = active_cache[next];
 273                int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
 274                if (!cmp)
 275                        return -next-1;
 276                if (cmp < 0) {
 277                        last = next;
 278                        continue;
 279                }
 280                first = next+1;
 281        }
 282        return first;
 283}
 284
 285int remove_file_from_cache(char *path)
 286{
 287        int pos = cache_name_pos(path, strlen(path));
 288        if (pos < 0) {
 289                pos = -pos-1;
 290                active_nr--;
 291                if (pos < active_nr)
 292                        memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
 293        }
 294        return 0;
 295}
 296
 297int add_cache_entry(struct cache_entry *ce)
 298{
 299        int pos;
 300
 301        pos = cache_name_pos(ce->name, ce->namelen);
 302
 303        /* existing match? Just replace it */
 304        if (pos < 0) {
 305                active_cache[-pos-1] = ce;
 306                return 0;
 307        }
 308
 309        /* Make sure the array is big enough .. */
 310        if (active_nr == active_alloc) {
 311                active_alloc = alloc_nr(active_alloc);
 312                active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
 313        }
 314
 315        /* Add it in.. */
 316        active_nr++;
 317        if (active_nr > pos)
 318                memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
 319        active_cache[pos] = ce;
 320        return 0;
 321}
 322
 323static int verify_hdr(struct cache_header *hdr, unsigned long size)
 324{
 325        SHA_CTX c;
 326        unsigned char sha1[20];
 327
 328        if (hdr->signature != CACHE_SIGNATURE)
 329                return error("bad signature");
 330        if (hdr->version != 1)
 331                return error("bad version");
 332        SHA1_Init(&c);
 333        SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
 334        SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
 335        SHA1_Final(sha1, &c);
 336        if (memcmp(sha1, hdr->sha1, 20))
 337                return error("bad header sha1");
 338        return 0;
 339}
 340
 341int read_cache(void)
 342{
 343        int fd, i;
 344        struct stat st;
 345        unsigned long size, offset;
 346        void *map;
 347        struct cache_header *hdr;
 348
 349        errno = EBUSY;
 350        if (active_cache)
 351                return error("more than one cachefile");
 352        errno = ENOENT;
 353        sha1_file_directory = getenv(DB_ENVIRONMENT);
 354        if (!sha1_file_directory)
 355                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
 356        if (access(sha1_file_directory, X_OK) < 0)
 357                return error("no access to SHA1 file directory");
 358        fd = open(".dircache/index", O_RDONLY);
 359        if (fd < 0)
 360                return (errno == ENOENT) ? 0 : error("open failed");
 361
 362        size = 0; // avoid gcc warning
 363        map = (void *)-1;
 364        if (!fstat(fd, &st)) {
 365                size = st.st_size;
 366                errno = EINVAL;
 367                if (size >= sizeof(struct cache_header))
 368                        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 369        }
 370        close(fd);
 371        if (-1 == (int)(long)map)
 372                return error("mmap failed");
 373
 374        hdr = map;
 375        if (verify_hdr(hdr, size) < 0)
 376                goto unmap;
 377
 378        active_nr = hdr->entries;
 379        active_alloc = alloc_nr(active_nr);
 380        active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
 381
 382        offset = sizeof(*hdr);
 383        for (i = 0; i < hdr->entries; i++) {
 384                struct cache_entry *ce = map + offset;
 385                offset = offset + ce_size(ce);
 386                active_cache[i] = ce;
 387        }
 388        return active_nr;
 389
 390unmap:
 391        munmap(map, size);
 392        errno = EINVAL;
 393        return error("verify header failed");
 394}
 395
 396int write_cache(int newfd, struct cache_entry **cache, int entries)
 397{
 398        SHA_CTX c;
 399        struct cache_header hdr;
 400        int i;
 401
 402        hdr.signature = CACHE_SIGNATURE;
 403        hdr.version = 1;
 404        hdr.entries = entries;
 405
 406        SHA1_Init(&c);
 407        SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
 408        for (i = 0; i < entries; i++) {
 409                struct cache_entry *ce = cache[i];
 410                int size = ce_size(ce);
 411                SHA1_Update(&c, ce, size);
 412        }
 413        SHA1_Final(hdr.sha1, &c);
 414
 415        if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
 416                return -1;
 417
 418        for (i = 0; i < entries; i++) {
 419                struct cache_entry *ce = cache[i];
 420                int size = ce_size(ce);
 421                if (write(newfd, ce, size) != size)
 422                        return -1;
 423        }
 424        return 0;
 425}