Andrew's git - gitweb.git/blob

8e90d2c3b6ae056d2b8f0410b4f12f0992bb7baf
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6#include <stdarg.h>
   7#include "cache.h"
   8
   9const char *sha1_file_directory = NULL;
  10struct cache_entry **active_cache = NULL;
  11unsigned int active_nr = 0, active_alloc = 0;
  12
  13void usage(const char *err)
  14{
  15        fprintf(stderr, "usage: %s\n", err);
  16        exit(1);
  17}
  18
  19static void report(const char *prefix, const char *err, va_list params)
  20{
  21        fputs(prefix, stderr);
  22        vfprintf(stderr, err, params);
  23        fputs("\n", stderr);
  24}
  25
  26void die(const char *err, ...)
  27{
  28        va_list params;
  29
  30        va_start(params, err);
  31        report("fatal: ", err, params);
  32        va_end(params);
  33        exit(1);
  34}
  35
  36int error(const char *err, ...)
  37{
  38        va_list params;
  39
  40        va_start(params, err);
  41        report("error: ", err, params);
  42        va_end(params);
  43        return -1;
  44}
  45
  46
  47static unsigned hexval(char c)
  48{
  49        if (c >= '0' && c <= '9')
  50                return c - '0';
  51        if (c >= 'a' && c <= 'f')
  52                return c - 'a' + 10;
  53        if (c >= 'A' && c <= 'F')
  54                return c - 'A' + 10;
  55        return ~0;
  56}
  57
  58int get_sha1_hex(const char *hex, unsigned char *sha1)
  59{
  60        int i;
  61        for (i = 0; i < 20; i++) {
  62                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  63                if (val & ~0xff)
  64                        return -1;
  65                *sha1++ = val;
  66                hex += 2;
  67        }
  68        return 0;
  69}
  70
  71char * sha1_to_hex(const unsigned char *sha1)
  72{
  73        static char buffer[50];
  74        static const char hex[] = "0123456789abcdef";
  75        char *buf = buffer;
  76        int i;
  77
  78        for (i = 0; i < 20; i++) {
  79                unsigned int val = *sha1++;
  80                *buf++ = hex[val >> 4];
  81                *buf++ = hex[val & 0xf];
  82        }
  83        return buffer;
  84}
  85
  86/*
  87 * NOTE! This returns a statically allocated buffer, so you have to be
  88 * careful about using it. Do a "strdup()" if you need to save the
  89 * filename.
  90 */
  91char *sha1_file_name(const unsigned char *sha1)
  92{
  93        int i;
  94        static char *name, *base;
  95
  96        if (!base) {
  97                char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
  98                int len = strlen(sha1_file_directory);
  99                base = malloc(len + 60);
 100                memcpy(base, sha1_file_directory, len);
 101                memset(base+len, 0, 60);
 102                base[len] = '/';
 103                base[len+3] = '/';
 104                name = base + len + 1;
 105        }
 106        for (i = 0; i < 20; i++) {
 107                static char hex[] = "0123456789abcdef";
 108                unsigned int val = sha1[i];
 109                char *pos = name + i*2 + (i > 0);
 110                *pos++ = hex[val >> 4];
 111                *pos = hex[val & 0xf];
 112        }
 113        return base;
 114}
 115
 116int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
 117{
 118        unsigned char real_sha1[20];
 119        SHA_CTX c;
 120
 121        SHA1_Init(&c);
 122        SHA1_Update(&c, map, size);
 123        SHA1_Final(real_sha1, &c);
 124        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 125}
 126
 127void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 128{
 129        char *filename = sha1_file_name(sha1);
 130        int fd = open(filename, O_RDONLY);
 131        struct stat st;
 132        void *map;
 133
 134        if (fd < 0) {
 135                perror(filename);
 136                return NULL;
 137        }
 138        if (fstat(fd, &st) < 0) {
 139                close(fd);
 140                return NULL;
 141        }
 142        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 143        close(fd);
 144        if (-1 == (int)(long)map)
 145                return NULL;
 146        *size = st.st_size;
 147        return map;
 148}
 149
 150void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 151{
 152        int ret, bytes;
 153        z_stream stream;
 154        char buffer[8192];
 155        char *buf;
 156
 157        /* Get the data stream */
 158        memset(&stream, 0, sizeof(stream));
 159        stream.next_in = map;
 160        stream.avail_in = mapsize;
 161        stream.next_out = buffer;
 162        stream.avail_out = sizeof(buffer);
 163
 164        inflateInit(&stream);
 165        ret = inflate(&stream, 0);
 166        if (sscanf(buffer, "%10s %lu", type, size) != 2)
 167                return NULL;
 168
 169        bytes = strlen(buffer) + 1;
 170        buf = malloc(*size);
 171        if (!buf)
 172                return NULL;
 173
 174        memcpy(buf, buffer + bytes, stream.total_out - bytes);
 175        bytes = stream.total_out - bytes;
 176        if (bytes < *size && ret == Z_OK) {
 177                stream.next_out = buf + bytes;
 178                stream.avail_out = *size - bytes;
 179                while (inflate(&stream, Z_FINISH) == Z_OK)
 180                        /* nothing */;
 181        }
 182        inflateEnd(&stream);
 183        return buf;
 184}
 185
 186void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 187{
 188        unsigned long mapsize;
 189        void *map, *buf;
 190
 191        map = map_sha1_file(sha1, &mapsize);
 192        if (map) {
 193                buf = unpack_sha1_file(map, mapsize, type, size);
 194                munmap(map, mapsize);
 195                return buf;
 196        }
 197        return NULL;
 198}
 199
 200int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 201{
 202        int size;
 203        char *compressed;
 204        z_stream stream;
 205        unsigned char sha1[20];
 206        SHA_CTX c;
 207
 208        /* Set it up */
 209        memset(&stream, 0, sizeof(stream));
 210        deflateInit(&stream, Z_BEST_COMPRESSION);
 211        size = deflateBound(&stream, len);
 212        compressed = malloc(size);
 213
 214        /* Compress it */
 215        stream.next_in = buf;
 216        stream.avail_in = len;
 217        stream.next_out = compressed;
 218        stream.avail_out = size;
 219        while (deflate(&stream, Z_FINISH) == Z_OK)
 220                /* nothing */;
 221        deflateEnd(&stream);
 222        size = stream.total_out;
 223
 224        /* Sha1.. */
 225        SHA1_Init(&c);
 226        SHA1_Update(&c, compressed, size);
 227        SHA1_Final(sha1, &c);
 228
 229        if (write_sha1_buffer(sha1, compressed, size) < 0)
 230                return -1;
 231        if (returnsha1)
 232                memcpy(returnsha1, sha1, 20);
 233        return 0;
 234}
 235
 236static inline int collision_check(char *filename, void *buf, unsigned int size)
 237{
 238#ifdef COLLISION_CHECK
 239        void *map;
 240        int fd = open(filename, O_RDONLY);
 241        struct stat st;
 242        int cmp;
 243
 244        /* Unreadable object, or object went away? Strange. */
 245        if (fd < 0)
 246                return -1;
 247
 248        if (fstat(fd, &st) < 0 || size != st.st_size)
 249                return -1;
 250
 251        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 252        close(fd);
 253        if (map == MAP_FAILED)
 254                return -1;
 255        cmp = memcmp(buf, map, size);
 256        munmap(map, size);
 257        if (cmp)
 258                return -1;
 259#endif
 260        return 0;
 261}
 262
 263int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
 264{
 265        char *filename = sha1_file_name(sha1);
 266        int fd;
 267
 268        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 269        if (fd < 0) {
 270                if (errno != EEXIST)
 271                        return -1;
 272                if (collision_check(filename, buf, size))
 273                        return error("SHA1 collision detected!"
 274                                        " This is bad, bad, BAD!\a\n");
 275                return 0;
 276        }
 277        write(fd, buf, size);
 278        close(fd);
 279        return 0;
 280}
 281
 282int cache_match_stat(struct cache_entry *ce, struct stat *st)
 283{
 284        unsigned int changed = 0;
 285
 286        /* nsec seems unreliable - not all filesystems support it, so
 287         * as long as it is in the inode cache you get right nsec
 288         * but after it gets flushed, you get zero nsec. */
 289        if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec
 290#ifdef NSEC
 291            || ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec
 292#endif
 293            )
 294                changed |= MTIME_CHANGED;
 295        if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec
 296#ifdef NSEC
 297            || ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec
 298#endif
 299            )
 300                changed |= CTIME_CHANGED;
 301        if (ce->st_uid != (unsigned int)st->st_uid ||
 302            ce->st_gid != (unsigned int)st->st_gid)
 303                changed |= OWNER_CHANGED;
 304        if (ce->st_mode != (unsigned int)st->st_mode)
 305                changed |= MODE_CHANGED;
 306        if (ce->st_dev != (unsigned int)st->st_dev ||
 307            ce->st_ino != (unsigned int)st->st_ino)
 308                changed |= INODE_CHANGED;
 309        if (ce->st_size != (unsigned int)st->st_size)
 310                changed |= DATA_CHANGED;
 311        return changed;
 312}
 313
 314int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
 315{
 316        int len = len1 < len2 ? len1 : len2;
 317        int cmp;
 318
 319        cmp = memcmp(name1, name2, len);
 320        if (cmp)
 321                return cmp;
 322        if (len1 < len2)
 323                return -1;
 324        if (len1 > len2)
 325                return 1;
 326        return 0;
 327}
 328
 329int cache_name_pos(const char *name, int namelen)
 330{
 331        int first, last;
 332
 333        first = 0;
 334        last = active_nr;
 335        while (last > first) {
 336                int next = (last + first) >> 1;
 337                struct cache_entry *ce = active_cache[next];
 338                int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
 339                if (!cmp)
 340                        return next;
 341                if (cmp < 0) {
 342                        last = next;
 343                        continue;
 344                }
 345                first = next+1;
 346        }
 347        return -first-1;
 348}
 349
 350int remove_file_from_cache(char *path)
 351{
 352        int pos = cache_name_pos(path, strlen(path));
 353        if (pos >= 0) {
 354                active_nr--;
 355                if (pos < active_nr)
 356                        memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
 357        }
 358        return 0;
 359}
 360
 361int add_cache_entry(struct cache_entry *ce, int ok_to_add)
 362{
 363        int pos;
 364
 365        pos = cache_name_pos(ce->name, ce->namelen);
 366
 367        /* existing match? Just replace it */
 368        if (pos >= 0) {
 369                active_cache[pos] = ce;
 370                return 0;
 371        }
 372        pos = -pos-1;
 373
 374        if (!ok_to_add)
 375                return -1;
 376
 377        /* Make sure the array is big enough .. */
 378        if (active_nr == active_alloc) {
 379                active_alloc = alloc_nr(active_alloc);
 380                active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
 381        }
 382
 383        /* Add it in.. */
 384        active_nr++;
 385        if (active_nr > pos)
 386                memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
 387        active_cache[pos] = ce;
 388        return 0;
 389}
 390
 391static int verify_hdr(struct cache_header *hdr, unsigned long size)
 392{
 393        SHA_CTX c;
 394        unsigned char sha1[20];
 395
 396        if (hdr->signature != CACHE_SIGNATURE)
 397                return error("bad signature");
 398        if (hdr->version != 1)
 399                return error("bad version");
 400        SHA1_Init(&c);
 401        SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
 402        SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
 403        SHA1_Final(sha1, &c);
 404        if (memcmp(sha1, hdr->sha1, 20))
 405                return error("bad header sha1");
 406        return 0;
 407}
 408
 409int read_cache(void)
 410{
 411        int fd, i;
 412        struct stat st;
 413        unsigned long size, offset;
 414        void *map;
 415        struct cache_header *hdr;
 416
 417        errno = EBUSY;
 418        if (active_cache)
 419                return error("more than one cachefile");
 420        errno = ENOENT;
 421        sha1_file_directory = getenv(DB_ENVIRONMENT);
 422        if (!sha1_file_directory)
 423                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
 424        if (access(sha1_file_directory, X_OK) < 0)
 425                return error("no access to SHA1 file directory");
 426        fd = open(".git/index", O_RDONLY);
 427        if (fd < 0)
 428                return (errno == ENOENT) ? 0 : error("open failed");
 429
 430        size = 0; // avoid gcc warning
 431        map = (void *)-1;
 432        if (!fstat(fd, &st)) {
 433                size = st.st_size;
 434                errno = EINVAL;
 435                if (size >= sizeof(struct cache_header))
 436                        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 437        }
 438        close(fd);
 439        if (-1 == (int)(long)map)
 440                return error("mmap failed");
 441
 442        hdr = map;
 443        if (verify_hdr(hdr, size) < 0)
 444                goto unmap;
 445
 446        active_nr = hdr->entries;
 447        active_alloc = alloc_nr(active_nr);
 448        active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
 449
 450        offset = sizeof(*hdr);
 451        for (i = 0; i < hdr->entries; i++) {
 452                struct cache_entry *ce = map + offset;
 453                offset = offset + ce_size(ce);
 454                active_cache[i] = ce;
 455        }
 456        return active_nr;
 457
 458unmap:
 459        munmap(map, size);
 460        errno = EINVAL;
 461        return error("verify header failed");
 462}
 463
 464int write_cache(int newfd, struct cache_entry **cache, int entries)
 465{
 466        SHA_CTX c;
 467        struct cache_header hdr;
 468        int i;
 469
 470        hdr.signature = CACHE_SIGNATURE;
 471        hdr.version = 1;
 472        hdr.entries = entries;
 473
 474        SHA1_Init(&c);
 475        SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
 476        for (i = 0; i < entries; i++) {
 477                struct cache_entry *ce = cache[i];
 478                int size = ce_size(ce);
 479                SHA1_Update(&c, ce, size);
 480        }
 481        SHA1_Final(hdr.sha1, &c);
 482
 483        if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
 484                return -1;
 485
 486        for (i = 0; i < entries; i++) {
 487                struct cache_entry *ce = cache[i];
 488                int size = ce_size(ce);
 489                if (write(newfd, ce, size) != size)
 490                        return -1;
 491        }
 492        return 0;
 493}