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472 lines
9.9 KiB
472 lines
9.9 KiB
/* |
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* GIT - The information manager from hell |
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* |
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* Copyright (C) Linus Torvalds, 2005 |
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* |
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* This handles basic git sha1 object files - packing, unpacking, |
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* creation etc. |
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*/ |
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#include <stdarg.h> |
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#include "cache.h" |
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const char *sha1_file_directory = NULL; |
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#ifndef O_NOATIME |
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#if defined(__linux__) && (defined(__i386__) || defined(__PPC__)) |
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#define O_NOATIME 01000000 |
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#else |
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#define O_NOATIME 0 |
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#endif |
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#endif |
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static unsigned int sha1_file_open_flag = O_NOATIME; |
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static unsigned hexval(char c) |
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{ |
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if (c >= '0' && c <= '9') |
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return c - '0'; |
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if (c >= 'a' && c <= 'f') |
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return c - 'a' + 10; |
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if (c >= 'A' && c <= 'F') |
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return c - 'A' + 10; |
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return ~0; |
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} |
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int get_sha1_hex(const char *hex, unsigned char *sha1) |
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{ |
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int i; |
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for (i = 0; i < 20; i++) { |
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unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]); |
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if (val & ~0xff) |
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return -1; |
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*sha1++ = val; |
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hex += 2; |
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} |
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return 0; |
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} |
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int get_sha1_file(const char *path, unsigned char *result) |
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{ |
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char buffer[60]; |
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int fd = open(path, O_RDONLY); |
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int len; |
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if (fd < 0) |
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return -1; |
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len = read(fd, buffer, sizeof(buffer)); |
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close(fd); |
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if (len < 40) |
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return -1; |
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return get_sha1_hex(buffer, result); |
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} |
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int get_sha1(const char *str, unsigned char *sha1) |
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{ |
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static char pathname[PATH_MAX]; |
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static const char *prefix[] = { |
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"", |
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"refs", |
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"refs/tags", |
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"refs/heads", |
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"refs/snap", |
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NULL |
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}; |
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const char *gitdir; |
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const char **p; |
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if (!get_sha1_hex(str, sha1)) |
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return 0; |
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gitdir = ".git"; |
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for (p = prefix; *p; p++) { |
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snprintf(pathname, sizeof(pathname), "%s/%s/%s", gitdir, *p, str); |
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if (!get_sha1_file(pathname, sha1)) |
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return 0; |
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} |
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return -1; |
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} |
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char * sha1_to_hex(const unsigned char *sha1) |
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{ |
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static char buffer[50]; |
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static const char hex[] = "0123456789abcdef"; |
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char *buf = buffer; |
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int i; |
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for (i = 0; i < 20; i++) { |
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unsigned int val = *sha1++; |
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*buf++ = hex[val >> 4]; |
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*buf++ = hex[val & 0xf]; |
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} |
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return buffer; |
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} |
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/* |
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* NOTE! This returns a statically allocated buffer, so you have to be |
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* careful about using it. Do a "strdup()" if you need to save the |
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* filename. |
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*/ |
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char *sha1_file_name(const unsigned char *sha1) |
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{ |
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int i; |
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static char *name, *base; |
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if (!base) { |
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char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT; |
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int len = strlen(sha1_file_directory); |
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base = xmalloc(len + 60); |
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memcpy(base, sha1_file_directory, len); |
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memset(base+len, 0, 60); |
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base[len] = '/'; |
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base[len+3] = '/'; |
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name = base + len + 1; |
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} |
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for (i = 0; i < 20; i++) { |
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static char hex[] = "0123456789abcdef"; |
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unsigned int val = sha1[i]; |
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char *pos = name + i*2 + (i > 0); |
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*pos++ = hex[val >> 4]; |
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*pos = hex[val & 0xf]; |
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} |
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return base; |
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} |
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int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type) |
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{ |
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char header[100]; |
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unsigned char real_sha1[20]; |
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SHA_CTX c; |
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SHA1_Init(&c); |
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SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size)); |
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SHA1_Update(&c, map, size); |
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SHA1_Final(real_sha1, &c); |
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return memcmp(sha1, real_sha1, 20) ? -1 : 0; |
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} |
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void *map_sha1_file(const unsigned char *sha1, unsigned long *size) |
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{ |
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char *filename = sha1_file_name(sha1); |
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struct stat st; |
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void *map; |
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int fd; |
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fd = open(filename, O_RDONLY | sha1_file_open_flag); |
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if (fd < 0) { |
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/* See if it works without O_NOATIME */ |
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switch (sha1_file_open_flag) { |
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default: |
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fd = open(filename, O_RDONLY); |
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if (fd >= 0) |
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break; |
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/* Fallthrough */ |
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case 0: |
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perror(filename); |
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return NULL; |
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} |
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/* If it failed once, it will probably fail again. Stop using O_NOATIME */ |
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sha1_file_open_flag = 0; |
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} |
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if (fstat(fd, &st) < 0) { |
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close(fd); |
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return NULL; |
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} |
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map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); |
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close(fd); |
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if (-1 == (int)(long)map) |
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return NULL; |
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*size = st.st_size; |
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return map; |
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} |
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void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size) |
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{ |
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int ret, bytes; |
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z_stream stream; |
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char buffer[8192]; |
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char *buf; |
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/* Get the data stream */ |
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memset(&stream, 0, sizeof(stream)); |
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stream.next_in = map; |
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stream.avail_in = mapsize; |
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stream.next_out = buffer; |
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stream.avail_out = sizeof(buffer); |
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inflateInit(&stream); |
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ret = inflate(&stream, 0); |
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if (ret < Z_OK) |
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return NULL; |
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if (sscanf(buffer, "%10s %lu", type, size) != 2) |
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return NULL; |
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bytes = strlen(buffer) + 1; |
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buf = xmalloc(*size); |
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memcpy(buf, buffer + bytes, stream.total_out - bytes); |
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bytes = stream.total_out - bytes; |
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if (bytes < *size && ret == Z_OK) { |
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stream.next_out = buf + bytes; |
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stream.avail_out = *size - bytes; |
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while (inflate(&stream, Z_FINISH) == Z_OK) |
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/* nothing */; |
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} |
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inflateEnd(&stream); |
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return buf; |
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} |
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void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size) |
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{ |
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unsigned long mapsize; |
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void *map, *buf; |
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map = map_sha1_file(sha1, &mapsize); |
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if (map) { |
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buf = unpack_sha1_file(map, mapsize, type, size); |
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munmap(map, mapsize); |
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return buf; |
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} |
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return NULL; |
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} |
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void *read_object_with_reference(const unsigned char *sha1, |
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const unsigned char *required_type, |
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unsigned long *size, |
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unsigned char *actual_sha1_return) |
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{ |
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char type[20]; |
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void *buffer; |
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unsigned long isize; |
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unsigned char actual_sha1[20]; |
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memcpy(actual_sha1, sha1, 20); |
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while (1) { |
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int ref_length = -1; |
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const char *ref_type = NULL; |
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buffer = read_sha1_file(actual_sha1, type, &isize); |
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if (!buffer) |
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return NULL; |
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if (!strcmp(type, required_type)) { |
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*size = isize; |
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if (actual_sha1_return) |
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memcpy(actual_sha1_return, actual_sha1, 20); |
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return buffer; |
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} |
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/* Handle references */ |
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else if (!strcmp(type, "commit")) |
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ref_type = "tree "; |
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else if (!strcmp(type, "tag")) |
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ref_type = "object "; |
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else { |
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free(buffer); |
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return NULL; |
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} |
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ref_length = strlen(ref_type); |
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if (memcmp(buffer, ref_type, ref_length) || |
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get_sha1_hex(buffer + ref_length, actual_sha1)) { |
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free(buffer); |
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return NULL; |
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} |
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/* Now we have the ID of the referred-to object in |
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* actual_sha1. Check again. */ |
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} |
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} |
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int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *returnsha1) |
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{ |
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int size; |
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char *compressed; |
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z_stream stream; |
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unsigned char sha1[20]; |
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SHA_CTX c; |
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char *filename; |
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static char tmpfile[PATH_MAX]; |
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char hdr[50]; |
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int fd, hdrlen, ret; |
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/* Generate the header */ |
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hdrlen = sprintf(hdr, "%s %lu", type, len)+1; |
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/* Sha1.. */ |
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SHA1_Init(&c); |
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SHA1_Update(&c, hdr, hdrlen); |
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SHA1_Update(&c, buf, len); |
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SHA1_Final(sha1, &c); |
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if (returnsha1) |
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memcpy(returnsha1, sha1, 20); |
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filename = sha1_file_name(sha1); |
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fd = open(filename, O_RDONLY); |
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if (fd >= 0) { |
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/* |
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* FIXME!!! We might do collision checking here, but we'd |
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* need to uncompress the old file and check it. Later. |
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*/ |
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close(fd); |
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return 0; |
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} |
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if (errno != ENOENT) { |
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fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno)); |
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return -1; |
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} |
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snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory()); |
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fd = mkstemp(tmpfile); |
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if (fd < 0) { |
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fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno)); |
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return -1; |
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} |
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/* Set it up */ |
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memset(&stream, 0, sizeof(stream)); |
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deflateInit(&stream, Z_BEST_COMPRESSION); |
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size = deflateBound(&stream, len+hdrlen); |
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compressed = xmalloc(size); |
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/* Compress it */ |
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stream.next_out = compressed; |
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stream.avail_out = size; |
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/* First header.. */ |
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stream.next_in = hdr; |
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stream.avail_in = hdrlen; |
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while (deflate(&stream, 0) == Z_OK) |
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/* nothing */ |
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/* Then the data itself.. */ |
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stream.next_in = buf; |
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stream.avail_in = len; |
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while (deflate(&stream, Z_FINISH) == Z_OK) |
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/* nothing */; |
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deflateEnd(&stream); |
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size = stream.total_out; |
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if (write(fd, compressed, size) != size) |
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die("unable to write file"); |
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fchmod(fd, 0444); |
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close(fd); |
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ret = link(tmpfile, filename); |
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if (ret < 0) { |
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ret = errno; |
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/* |
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* Coda hack - coda doesn't like cross-directory links, |
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* so we fall back to a rename, which will mean that it |
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* won't be able to check collisions, but that's not a |
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* big deal. |
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* |
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* When this succeeds, we just return 0. We have nothing |
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* left to unlink. |
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*/ |
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if (ret == EXDEV && !rename(tmpfile, filename)) |
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return 0; |
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} |
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unlink(tmpfile); |
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if (ret) { |
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if (ret != EEXIST) { |
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fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret)); |
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return -1; |
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} |
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/* FIXME!!! Collision check here ? */ |
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} |
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return 0; |
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} |
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int write_sha1_from_fd(const unsigned char *sha1, int fd) |
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{ |
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char *filename = sha1_file_name(sha1); |
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int local; |
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z_stream stream; |
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unsigned char real_sha1[20]; |
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char buf[4096]; |
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char discard[4096]; |
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int ret; |
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SHA_CTX c; |
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local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); |
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if (local < 0) |
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return error("Couldn't open %s\n", filename); |
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memset(&stream, 0, sizeof(stream)); |
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inflateInit(&stream); |
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SHA1_Init(&c); |
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do { |
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ssize_t size; |
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size = read(fd, buf, 4096); |
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if (size <= 0) { |
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close(local); |
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unlink(filename); |
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if (!size) |
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return error("Connection closed?"); |
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perror("Reading from connection"); |
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return -1; |
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} |
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write(local, buf, size); |
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stream.avail_in = size; |
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stream.next_in = buf; |
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do { |
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stream.next_out = discard; |
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stream.avail_out = sizeof(discard); |
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ret = inflate(&stream, Z_SYNC_FLUSH); |
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SHA1_Update(&c, discard, sizeof(discard) - |
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stream.avail_out); |
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} while (stream.avail_in && ret == Z_OK); |
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} while (ret == Z_OK); |
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inflateEnd(&stream); |
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close(local); |
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SHA1_Final(real_sha1, &c); |
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if (ret != Z_STREAM_END) { |
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unlink(filename); |
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return error("File %s corrupted", sha1_to_hex(sha1)); |
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} |
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if (memcmp(sha1, real_sha1, 20)) { |
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unlink(filename); |
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return error("File %s has bad hash\n", sha1_to_hex(sha1)); |
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} |
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return 0; |
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} |
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int has_sha1_file(const unsigned char *sha1) |
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{ |
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char *filename = sha1_file_name(sha1); |
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struct stat st; |
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if (!stat(filename, &st)) |
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return 1; |
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return 0; |
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} |
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int index_fd(unsigned char *sha1, int fd, struct stat *st) |
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{ |
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unsigned long size = st->st_size; |
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void *buf; |
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int ret; |
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buf = ""; |
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if (size) |
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buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); |
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close(fd); |
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if ((int)(long)buf == -1) |
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return -1; |
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ret = write_sha1_file(buf, size, "blob", sha1); |
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if (size) |
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munmap(buf, size); |
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return ret; |
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}
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