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Do the usage and error reporting in "usage.c", and the sha1 file accesses in "sha1_file.c". Small, nice, easily separated parts. Good.maint
Linus Torvalds
20 years ago
4 changed files with 288 additions and 271 deletions
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/* |
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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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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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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 = malloc(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) |
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{ |
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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, 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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int fd = open(filename, O_RDONLY); |
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struct stat st; |
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void *map; |
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if (fd < 0) { |
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perror(filename); |
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return NULL; |
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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 (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 = malloc(*size); |
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if (!buf) |
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return NULL; |
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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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int write_sha1_file(char *buf, unsigned len, 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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/* 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); |
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compressed = malloc(size); |
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/* Compress it */ |
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stream.next_in = buf; |
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stream.avail_in = len; |
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stream.next_out = compressed; |
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stream.avail_out = size; |
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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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/* Sha1.. */ |
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SHA1_Init(&c); |
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SHA1_Update(&c, compressed, size); |
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SHA1_Final(sha1, &c); |
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if (write_sha1_buffer(sha1, compressed, size) < 0) |
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return -1; |
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if (returnsha1) |
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memcpy(returnsha1, sha1, 20); |
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return 0; |
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} |
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static inline int collision_check(char *filename, void *buf, unsigned int size) |
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{ |
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#ifdef COLLISION_CHECK |
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void *map; |
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int fd = open(filename, O_RDONLY); |
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struct stat st; |
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int cmp; |
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/* Unreadable object, or object went away? Strange. */ |
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if (fd < 0) |
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return -1; |
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if (fstat(fd, &st) < 0 || size != st.st_size) |
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return -1; |
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map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); |
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close(fd); |
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if (map == MAP_FAILED) |
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return -1; |
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cmp = memcmp(buf, map, size); |
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munmap(map, size); |
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if (cmp) |
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return -1; |
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#endif |
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return 0; |
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} |
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int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size) |
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{ |
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char *filename = sha1_file_name(sha1); |
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int fd; |
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fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666); |
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if (fd < 0) { |
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if (errno != EEXIST) |
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return -1; |
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if (collision_check(filename, buf, size)) |
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return error("SHA1 collision detected!" |
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" This is bad, bad, BAD!\a\n"); |
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return 0; |
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} |
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write(fd, buf, size); |
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close(fd); |
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return 0; |
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} |
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@ -0,0 +1,40 @@
@@ -0,0 +1,40 @@
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/* |
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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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#include <stdarg.h> |
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#include "cache.h" |
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static void report(const char *prefix, const char *err, va_list params) |
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{ |
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fputs(prefix, stderr); |
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vfprintf(stderr, err, params); |
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fputs("\n", stderr); |
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} |
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void usage(const char *err) |
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{ |
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fprintf(stderr, "usage: %s\n", err); |
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exit(1); |
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} |
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void die(const char *err, ...) |
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{ |
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va_list params; |
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va_start(params, err); |
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report("fatal: ", err, params); |
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va_end(params); |
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exit(1); |
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} |
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int error(const char *err, ...) |
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{ |
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va_list params; |
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va_start(params, err); |
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report("error: ", err, params); |
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va_end(params); |
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return -1; |
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} |
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