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c924a6e0fc4c36bad6f23cb87ee59518c771f936
   1#include "cache.h"
   2
   3const char *sha1_file_directory = NULL;
   4struct cache_entry **active_cache = NULL;
   5unsigned int active_nr = 0, active_alloc = 0;
   6
   7void usage(const char *err)
   8{
   9        fprintf(stderr, "read-tree: %s\n", err);
  10        exit(1);
  11}
  12
  13static unsigned hexval(char c)
  14{
  15        if (c >= '0' && c <= '9')
  16                return c - '0';
  17        if (c >= 'a' && c <= 'f')
  18                return c - 'a' + 10;
  19        if (c >= 'A' && c <= 'F')
  20                return c - 'A' + 10;
  21        return ~0;
  22}
  23
  24int get_sha1_hex(char *hex, unsigned char *sha1)
  25{
  26        int i;
  27        for (i = 0; i < 20; i++) {
  28                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  29                if (val & ~0xff)
  30                        return -1;
  31                *sha1++ = val;
  32                hex += 2;
  33        }
  34        return 0;
  35}
  36
  37char * sha1_to_hex(unsigned char *sha1)
  38{
  39        static char buffer[50];
  40        static const char hex[] = "0123456789abcdef";
  41        char *buf = buffer;
  42        int i;
  43
  44        for (i = 0; i < 20; i++) {
  45                unsigned int val = *sha1++;
  46                *buf++ = hex[val >> 4];
  47                *buf++ = hex[val & 0xf];
  48        }
  49        return buffer;
  50}
  51
  52/*
  53 * NOTE! This returns a statically allocated buffer, so you have to be
  54 * careful about using it. Do a "strdup()" if you need to save the
  55 * filename.
  56 */
  57char *sha1_file_name(unsigned char *sha1)
  58{
  59        int i;
  60        static char *name, *base;
  61
  62        if (!base) {
  63                char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
  64                int len = strlen(sha1_file_directory);
  65                base = malloc(len + 60);
  66                memcpy(base, sha1_file_directory, len);
  67                memset(base+len, 0, 60);
  68                base[len] = '/';
  69                base[len+3] = '/';
  70                name = base + len + 1;
  71        }
  72        for (i = 0; i < 20; i++) {
  73                static char hex[] = "0123456789abcdef";
  74                unsigned int val = sha1[i];
  75                char *pos = name + i*2 + (i > 0);
  76                *pos++ = hex[val >> 4];
  77                *pos = hex[val & 0xf];
  78        }
  79        return base;
  80}
  81
  82void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
  83{
  84        z_stream stream;
  85        char buffer[8192];
  86        struct stat st;
  87        int i, fd, ret, bytes;
  88        void *map, *buf;
  89        char *filename = sha1_file_name(sha1);
  90
  91        fd = open(filename, O_RDONLY);
  92        if (fd < 0) {
  93                perror(filename);
  94                return NULL;
  95        }
  96        if (fstat(fd, &st) < 0) {
  97                close(fd);
  98                return NULL;
  99        }
 100        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 101        close(fd);
 102        if (-1 == (int)(long)map)
 103                return NULL;
 104
 105        /* Get the data stream */
 106        memset(&stream, 0, sizeof(stream));
 107        stream.next_in = map;
 108        stream.avail_in = st.st_size;
 109        stream.next_out = buffer;
 110        stream.avail_out = sizeof(buffer);
 111
 112        inflateInit(&stream);
 113        ret = inflate(&stream, 0);
 114        if (sscanf(buffer, "%10s %lu", type, size) != 2)
 115                return NULL;
 116        bytes = strlen(buffer) + 1;
 117        buf = malloc(*size);
 118        if (!buf)
 119                return NULL;
 120
 121        memcpy(buf, buffer + bytes, stream.total_out - bytes);
 122        bytes = stream.total_out - bytes;
 123        if (bytes < *size && ret == Z_OK) {
 124                stream.next_out = buf + bytes;
 125                stream.avail_out = *size - bytes;
 126                while (inflate(&stream, Z_FINISH) == Z_OK)
 127                        /* nothing */;
 128        }
 129        inflateEnd(&stream);
 130        return buf;
 131}
 132
 133int write_sha1_file(char *buf, unsigned len)
 134{
 135        int size;
 136        char *compressed;
 137        z_stream stream;
 138        unsigned char sha1[20];
 139        SHA_CTX c;
 140
 141        /* Set it up */
 142        memset(&stream, 0, sizeof(stream));
 143        deflateInit(&stream, Z_BEST_COMPRESSION);
 144        size = deflateBound(&stream, len);
 145        compressed = malloc(size);
 146
 147        /* Compress it */
 148        stream.next_in = buf;
 149        stream.avail_in = len;
 150        stream.next_out = compressed;
 151        stream.avail_out = size;
 152        while (deflate(&stream, Z_FINISH) == Z_OK)
 153                /* nothing */;
 154        deflateEnd(&stream);
 155        size = stream.total_out;
 156
 157        /* Sha1.. */
 158        SHA1_Init(&c);
 159        SHA1_Update(&c, compressed, size);
 160        SHA1_Final(sha1, &c);
 161
 162        if (write_sha1_buffer(sha1, compressed, size) < 0)
 163                return -1;
 164        printf("%s\n", sha1_to_hex(sha1));
 165        return 0;
 166}
 167
 168int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
 169{
 170        char *filename = sha1_file_name(sha1);
 171        int i, fd;
 172
 173        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 174        if (fd < 0)
 175                return (errno == EEXIST) ? 0 : -1;
 176        write(fd, buf, size);
 177        close(fd);
 178        return 0;
 179}
 180
 181static int error(const char * string)
 182{
 183        fprintf(stderr, "error: %s\n", string);
 184        return -1;
 185}
 186
 187static int verify_hdr(struct cache_header *hdr, unsigned long size)
 188{
 189        SHA_CTX c;
 190        unsigned char sha1[20];
 191
 192        if (hdr->signature != CACHE_SIGNATURE)
 193                return error("bad signature");
 194        if (hdr->version != 1)
 195                return error("bad version");
 196        SHA1_Init(&c);
 197        SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
 198        SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
 199        SHA1_Final(sha1, &c);
 200        if (memcmp(sha1, hdr->sha1, 20))
 201                return error("bad header sha1");
 202        return 0;
 203}
 204
 205int read_cache(void)
 206{
 207        int fd, i;
 208        struct stat st;
 209        unsigned long size, offset;
 210        void *map;
 211        struct cache_header *hdr;
 212
 213        errno = EBUSY;
 214        if (active_cache)
 215                return error("more than one cachefile");
 216        errno = ENOENT;
 217        sha1_file_directory = getenv(DB_ENVIRONMENT);
 218        if (!sha1_file_directory)
 219                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
 220        if (access(sha1_file_directory, X_OK) < 0)
 221                return error("no access to SHA1 file directory");
 222        fd = open(".dircache/index", O_RDONLY);
 223        if (fd < 0)
 224                return (errno == ENOENT) ? 0 : error("open failed");
 225
 226        map = (void *)-1;
 227        if (!fstat(fd, &st)) {
 228                map = NULL;
 229                size = st.st_size;
 230                errno = EINVAL;
 231                if (size > sizeof(struct cache_header))
 232                        map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 233        }
 234        close(fd);
 235        if (-1 == (int)(long)map)
 236                return error("mmap failed");
 237
 238        hdr = map;
 239        if (verify_hdr(hdr, size) < 0)
 240                goto unmap;
 241
 242        active_nr = hdr->entries;
 243        active_alloc = alloc_nr(active_nr);
 244        active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
 245
 246        offset = sizeof(*hdr);
 247        for (i = 0; i < hdr->entries; i++) {
 248                struct cache_entry *ce = map + offset;
 249                offset = offset + ce_size(ce);
 250                active_cache[i] = ce;
 251        }
 252        return active_nr;
 253
 254unmap:
 255        munmap(map, size);
 256        errno = EINVAL;
 257        return error("verify header failed");
 258}
 259