Andrew's git - gitweb.git/blob

f1abae1442e72753dc8356bcbdc860be9a645bc4
   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        va_list args;
  15        char string[200];
  16
  17        va_start(args, err);
  18        vsnprintf(string, sizeof(string), err, args);
  19        va_end(args);
  20        fprintf(stderr, "%s\n", string);
  21        exit(1);
  22}
  23
  24static unsigned hexval(char c)
  25{
  26        if (c >= '0' && c <= '9')
  27                return c - '0';
  28        if (c >= 'a' && c <= 'f')
  29                return c - 'a' + 10;
  30        if (c >= 'A' && c <= 'F')
  31                return c - 'A' + 10;
  32        return ~0;
  33}
  34
  35int get_sha1_hex(const char *hex, unsigned char *sha1)
  36{
  37        int i;
  38        for (i = 0; i < 20; i++) {
  39                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  40                if (val & ~0xff)
  41                        return -1;
  42                *sha1++ = val;
  43                hex += 2;
  44        }
  45        return 0;
  46}
  47
  48char * sha1_to_hex(const unsigned char *sha1)
  49{
  50        static char buffer[50];
  51        static const char hex[] = "0123456789abcdef";
  52        char *buf = buffer;
  53        int i;
  54
  55        for (i = 0; i < 20; i++) {
  56                unsigned int val = *sha1++;
  57                *buf++ = hex[val >> 4];
  58                *buf++ = hex[val & 0xf];
  59        }
  60        return buffer;
  61}
  62
  63/*
  64 * NOTE! This returns a statically allocated buffer, so you have to be
  65 * careful about using it. Do a "strdup()" if you need to save the
  66 * filename.
  67 */
  68char *sha1_file_name(const unsigned char *sha1)
  69{
  70        int i;
  71        static char *name, *base;
  72
  73        if (!base) {
  74                char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
  75                int len = strlen(sha1_file_directory);
  76                base = malloc(len + 60);
  77                memcpy(base, sha1_file_directory, len);
  78                memset(base+len, 0, 60);
  79                base[len] = '/';
  80                base[len+3] = '/';
  81                name = base + len + 1;
  82        }
  83        for (i = 0; i < 20; i++) {
  84                static char hex[] = "0123456789abcdef";
  85                unsigned int val = sha1[i];
  86                char *pos = name + i*2 + (i > 0);
  87                *pos++ = hex[val >> 4];
  88                *pos = hex[val & 0xf];
  89        }
  90        return base;
  91}
  92
  93int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
  94{
  95        unsigned char real_sha1[20];
  96        SHA_CTX c;
  97
  98        SHA1_Init(&c);
  99        SHA1_Update(&c, map, size);
 100        SHA1_Final(real_sha1, &c);
 101        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 102}
 103
 104void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 105{
 106        char *filename = sha1_file_name(sha1);
 107        int fd = open(filename, O_RDONLY);
 108        struct stat st;
 109        void *map;
 110
 111        if (fd < 0) {
 112                perror(filename);
 113                return NULL;
 114        }
 115        if (fstat(fd, &st) < 0) {
 116                close(fd);  
 117                return NULL;
 118        }
 119        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 120        close(fd);
 121        if (-1 == (int)(long)map)
 122                return NULL;
 123        *size = st.st_size;
 124        return map;
 125}
 126
 127void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 128{
 129        int ret, bytes;
 130        z_stream stream;
 131        char buffer[8192];
 132        char *buf;
 133
 134        /* Get the data stream */
 135        memset(&stream, 0, sizeof(stream));
 136        stream.next_in = map;
 137        stream.avail_in = mapsize;
 138        stream.next_out = buffer;
 139        stream.avail_out = sizeof(buffer);
 140
 141        inflateInit(&stream);
 142        ret = inflate(&stream, 0);
 143        if (sscanf(buffer, "%10s %lu", type, size) != 2)
 144                return NULL;
 145
 146        bytes = strlen(buffer) + 1;
 147        buf = malloc(*size);
 148        if (!buf)
 149                return NULL;
 150
 151        memcpy(buf, buffer + bytes, stream.total_out - bytes);
 152        bytes = stream.total_out - bytes;
 153        if (bytes < *size && ret == Z_OK) {
 154                stream.next_out = buf + bytes;
 155                stream.avail_out = *size - bytes;
 156                while (inflate(&stream, Z_FINISH) == Z_OK)
 157                        /* nothing */;
 158        }
 159        inflateEnd(&stream);
 160        return buf;
 161}
 162
 163void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 164{
 165        unsigned long mapsize;
 166        void *map, *buf;
 167
 168        map = map_sha1_file(sha1, &mapsize);
 169        if (map) {
 170                buf = unpack_sha1_file(map, mapsize, type, size);
 171                munmap(map, mapsize);
 172                return buf;
 173        }
 174        return NULL;
 175}
 176
 177int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 178{
 179        int size;
 180        char *compressed;
 181        z_stream stream;
 182        unsigned char sha1[20];
 183        SHA_CTX c;
 184
 185        /* Set it up */
 186        memset(&stream, 0, sizeof(stream));
 187        deflateInit(&stream, Z_BEST_COMPRESSION);
 188        size = deflateBound(&stream, len);
 189        compressed = malloc(size);
 190
 191        /* Compress it */
 192        stream.next_in = buf;
 193        stream.avail_in = len;
 194        stream.next_out = compressed;
 195        stream.avail_out = size;
 196        while (deflate(&stream, Z_FINISH) == Z_OK)
 197                /* nothing */;
 198        deflateEnd(&stream);
 199        size = stream.total_out;
 200
 201        /* Sha1.. */
 202        SHA1_Init(&c);
 203        SHA1_Update(&c, compressed, size);
 204        SHA1_Final(sha1, &c);
 205
 206        if (write_sha1_buffer(sha1, compressed, size) < 0)
 207                return -1;
 208        if (returnsha1)
 209                memcpy(returnsha1, sha1, 20);
 210        return 0;
 211}
 212
 213int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
 214{
 215        char *filename = sha1_file_name(sha1);
 216        int fd;
 217
 218        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 219        if (fd < 0) {
 220                void *map;
 221                static int error(const char * string);
 222
 223                if (errno != EEXIST)
 224                        return -1;
 225#ifndef COLLISION_CHECK
 226                fd = open(filename, O_RDONLY);
 227                if (fd < 0)
 228                        return -1;
 229                map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 230                if (map == MAP_FAILED)
 231                        return -1;
 232                if (memcmp(buf, map, size))
 233                        return error("SHA1 collision detected!"
 234                                        " This is bad, bad, BAD!\a\n");
 235#endif
 236                return 0;
 237        }
 238        write(fd, buf, size);
 239        close(fd);
 240        return 0;
 241}
 242
 243static int error(const char * string)
 244{
 245        fprintf(stderr, "error: %s\n", string);
 246        return -1;
 247}
 248
 249int cache_match_stat(struct cache_entry *ce, struct stat *st)
 250{
 251        unsigned int changed = 0;
 252
 253        /* nsec seems unreliable - not all filesystems support it, so
 254         * as long as it is in the inode cache you get right nsec
 255         * but after it gets flushed, you get zero nsec. */
 256        if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec
 257#ifdef NSEC
 258            || ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec
 259#endif
 260            )
 261                changed |= MTIME_CHANGED;
 262        if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec
 263#ifdef NSEC
 264            || ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec
 265#endif
 266            )
 267                changed |= CTIME_CHANGED;
 268        if (ce->st_uid != (unsigned int)st->st_uid ||
 269            ce->st_gid != (unsigned int)st->st_gid)
 270                changed |= OWNER_CHANGED;
 271        if (ce->st_mode != (unsigned int)st->st_mode)
 272                changed |= MODE_CHANGED;
 273        if (ce->st_dev != (unsigned int)st->st_dev ||
 274            ce->st_ino != (unsigned int)st->st_ino)
 275                changed |= INODE_CHANGED;
 276        if (ce->st_size != (unsigned int)st->st_size)
 277                changed |= DATA_CHANGED;
 278        return changed;
 279}
 280
 281int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
 282{
 283        int len = len1 < len2 ? len1 : len2;
 284        int cmp;
 285
 286        cmp = memcmp(name1, name2, len);
 287        if (cmp)
 288                return cmp;
 289        if (len1 < len2)
 290                return -1;
 291        if (len1 > len2)
 292                return 1;
 293        return 0;
 294}
 295
 296int cache_name_pos(const char *name, int namelen)
 297{
 298        int first, last;
 299
 300        first = 0;
 301        last = active_nr;
 302        while (last > first) {
 303                int next = (last + first) >> 1;
 304                struct cache_entry *ce = active_cache[next];
 305                int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
 306                if (!cmp)
 307                        return next;
 308                if (cmp < 0) {
 309                        last = next;
 310                        continue;
 311                }
 312                first = next+1;
 313        }
 314        return -first-1;
 315}
 316
 317int remove_file_from_cache(char *path)
 318{
 319        int pos = cache_name_pos(path, strlen(path));
 320        if (pos >= 0) {
 321                active_nr--;
 322                if (pos < active_nr)
 323                        memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
 324        }
 325        return 0;
 326}
 327
 328int add_cache_entry(struct cache_entry *ce, int ok_to_add)
 329{
 330        int pos;
 331
 332        pos = cache_name_pos(ce->name, ce->namelen);
 333
 334        /* existing match? Just replace it */
 335        if (pos >= 0) {
 336                active_cache[pos] = ce;
 337                return 0;
 338        }
 339        pos = -pos-1;
 340
 341        if (!ok_to_add)
 342                return -1;
 343
 344        /* Make sure the array is big enough .. */
 345        if (active_nr == active_alloc) {
 346                active_alloc = alloc_nr(active_alloc);
 347                active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
 348        }
 349
 350        /* Add it in.. */
 351        active_nr++;
 352        if (active_nr > pos)
 353                memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
 354        active_cache[pos] = ce;
 355        return 0;
 356}
 357
 358static int verify_hdr(struct cache_header *hdr, unsigned long size)
 359{
 360        SHA_CTX c;
 361        unsigned char sha1[20];
 362
 363        if (hdr->signature != CACHE_SIGNATURE)
 364                return error("bad signature");
 365        if (hdr->version != 1)
 366                return error("bad version");
 367        SHA1_Init(&c);
 368        SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
 369        SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
 370        SHA1_Final(sha1, &c);
 371        if (memcmp(sha1, hdr->sha1, 20))
 372                return error("bad header sha1");
 373        return 0;
 374}
 375
 376int read_cache(void)
 377{
 378        int fd, i;
 379        struct stat st;
 380        unsigned long size, offset;
 381        void *map;
 382        struct cache_header *hdr;
 383
 384        errno = EBUSY;
 385        if (active_cache)
 386                return error("more than one cachefile");
 387        errno = ENOENT;
 388        sha1_file_directory = getenv(DB_ENVIRONMENT);
 389        if (!sha1_file_directory)
 390                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
 391        if (access(sha1_file_directory, X_OK) < 0)
 392                return error("no access to SHA1 file directory");
 393        fd = open(".git/index", O_RDONLY);
 394        if (fd < 0)
 395                return (errno == ENOENT) ? 0 : error("open failed");
 396
 397        size = 0; // avoid gcc warning
 398        map = (void *)-1;
 399        if (!fstat(fd, &st)) {
 400                size = st.st_size;
 401                errno = EINVAL;
 402                if (size >= sizeof(struct cache_header))
 403                        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 404        }
 405        close(fd);
 406        if (-1 == (int)(long)map)
 407                return error("mmap failed");
 408
 409        hdr = map;
 410        if (verify_hdr(hdr, size) < 0)
 411                goto unmap;
 412
 413        active_nr = hdr->entries;
 414        active_alloc = alloc_nr(active_nr);
 415        active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
 416
 417        offset = sizeof(*hdr);
 418        for (i = 0; i < hdr->entries; i++) {
 419                struct cache_entry *ce = map + offset;
 420                offset = offset + ce_size(ce);
 421                active_cache[i] = ce;
 422        }
 423        return active_nr;
 424
 425unmap:
 426        munmap(map, size);
 427        errno = EINVAL;
 428        return error("verify header failed");
 429}
 430
 431int write_cache(int newfd, struct cache_entry **cache, int entries)
 432{
 433        SHA_CTX c;
 434        struct cache_header hdr;
 435        int i;
 436
 437        hdr.signature = CACHE_SIGNATURE;
 438        hdr.version = 1;
 439        hdr.entries = entries;
 440
 441        SHA1_Init(&c);
 442        SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
 443        for (i = 0; i < entries; i++) {
 444                struct cache_entry *ce = cache[i];
 445                int size = ce_size(ce);
 446                SHA1_Update(&c, ce, size);
 447        }
 448        SHA1_Final(hdr.sha1, &c);
 449
 450        if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
 451                return -1;
 452
 453        for (i = 0; i < entries; i++) {
 454                struct cache_entry *ce = cache[i];
 455                int size = ce_size(ce);
 456                if (write(newfd, ce, size) != size)
 457                        return -1;
 458        }
 459        return 0;
 460}