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        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(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(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
  87void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
  88{
  89        z_stream stream;
  90        char buffer[8192];
  91        struct stat st;
  92        int i, fd, ret, bytes;
  93        void *map, *buf;
  94        char *filename = sha1_file_name(sha1);
  95
  96        fd = open(filename, O_RDONLY);
  97        if (fd < 0) {
  98                perror(filename);
  99                return NULL;
 100        }
 101        if (fstat(fd, &st) < 0) {
 102                close(fd);
 103                return NULL;
 104        }
 105        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 106        close(fd);
 107        if (-1 == (int)(long)map)
 108                return NULL;
 109
 110        /* Get the data stream */
 111        memset(&stream, 0, sizeof(stream));
 112        stream.next_in = map;
 113        stream.avail_in = st.st_size;
 114        stream.next_out = buffer;
 115        stream.avail_out = sizeof(buffer);
 116
 117        inflateInit(&stream);
 118        ret = inflate(&stream, 0);
 119        if (sscanf(buffer, "%10s %lu", type, size) != 2)
 120                return NULL;
 121        bytes = strlen(buffer) + 1;
 122        buf = malloc(*size);
 123        if (!buf)
 124                return NULL;
 125
 126        memcpy(buf, buffer + bytes, stream.total_out - bytes);
 127        bytes = stream.total_out - bytes;
 128        if (bytes < *size && ret == Z_OK) {
 129                stream.next_out = buf + bytes;
 130                stream.avail_out = *size - bytes;
 131                while (inflate(&stream, Z_FINISH) == Z_OK)
 132                        /* nothing */;
 133        }
 134        inflateEnd(&stream);
 135        return buf;
 136}
 137
 138int write_sha1_file(char *buf, unsigned len)
 139{
 140        int size;
 141        char *compressed;
 142        z_stream stream;
 143        unsigned char sha1[20];
 144        SHA_CTX c;
 145
 146        /* Set it up */
 147        memset(&stream, 0, sizeof(stream));
 148        deflateInit(&stream, Z_BEST_COMPRESSION);
 149        size = deflateBound(&stream, len);
 150        compressed = malloc(size);
 151
 152        /* Compress it */
 153        stream.next_in = buf;
 154        stream.avail_in = len;
 155        stream.next_out = compressed;
 156        stream.avail_out = size;
 157        while (deflate(&stream, Z_FINISH) == Z_OK)
 158                /* nothing */;
 159        deflateEnd(&stream);
 160        size = stream.total_out;
 161
 162        /* Sha1.. */
 163        SHA1_Init(&c);
 164        SHA1_Update(&c, compressed, size);
 165        SHA1_Final(sha1, &c);
 166
 167        if (write_sha1_buffer(sha1, compressed, size) < 0)
 168                return -1;
 169        printf("%s\n", sha1_to_hex(sha1));
 170        return 0;
 171}
 172
 173int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
 174{
 175        char *filename = sha1_file_name(sha1);
 176        int i, fd;
 177
 178        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 179        if (fd < 0)
 180                return (errno == EEXIST) ? 0 : -1;
 181        write(fd, buf, size);
 182        close(fd);
 183        return 0;
 184}
 185
 186static int error(const char * string)
 187{
 188        fprintf(stderr, "error: %s\n", string);
 189        return -1;
 190}
 191
 192static int verify_hdr(struct cache_header *hdr, unsigned long size)
 193{
 194        SHA_CTX c;
 195        unsigned char sha1[20];
 196
 197        if (hdr->signature != CACHE_SIGNATURE)
 198                return error("bad signature");
 199        if (hdr->version != 1)
 200                return error("bad version");
 201        SHA1_Init(&c);
 202        SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
 203        SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
 204        SHA1_Final(sha1, &c);
 205        if (memcmp(sha1, hdr->sha1, 20))
 206                return error("bad header sha1");
 207        return 0;
 208}
 209
 210int read_cache(void)
 211{
 212        int fd, i;
 213        struct stat st;
 214        unsigned long size, offset;
 215        void *map;
 216        struct cache_header *hdr;
 217
 218        errno = EBUSY;
 219        if (active_cache)
 220                return error("more than one cachefile");
 221        errno = ENOENT;
 222        sha1_file_directory = getenv(DB_ENVIRONMENT);
 223        if (!sha1_file_directory)
 224                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
 225        if (access(sha1_file_directory, X_OK) < 0)
 226                return error("no access to SHA1 file directory");
 227        fd = open(".dircache/index", O_RDONLY);
 228        if (fd < 0)
 229                return (errno == ENOENT) ? 0 : error("open failed");
 230
 231        map = (void *)-1;
 232        if (!fstat(fd, &st)) {
 233                map = NULL;
 234                size = st.st_size;
 235                errno = EINVAL;
 236                if (size > sizeof(struct cache_header))
 237                        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 238        }
 239        close(fd);
 240        if (-1 == (int)(long)map)
 241                return error("mmap failed");
 242
 243        hdr = map;
 244        if (verify_hdr(hdr, size) < 0)
 245                goto unmap;
 246
 247        active_nr = hdr->entries;
 248        active_alloc = alloc_nr(active_nr);
 249        active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
 250
 251        offset = sizeof(*hdr);
 252        for (i = 0; i < hdr->entries; i++) {
 253                struct cache_entry *ce = map + offset;
 254                offset = offset + ce_size(ce);
 255                active_cache[i] = ce;
 256        }
 257        return active_nr;
 258
 259unmap:
 260        munmap(map, size);
 261        errno = EINVAL;
 262        return error("verify header failed");
 263}
 264