Andrew's git - gitweb.git/blob

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