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git/pack-mtimes.c

129 lines
2.9 KiB

#include "git-compat-util.h"
#include "pack-mtimes.h"
#include "object-store.h"
#include "packfile.h"
static char *pack_mtimes_filename(struct packed_git *p)
{
size_t len;
if (!strip_suffix(p->pack_name, ".pack", &len))
BUG("pack_name does not end in .pack");
return xstrfmt("%.*s.mtimes", (int)len, p->pack_name);
}
#define MTIMES_HEADER_SIZE (12)
struct mtimes_header {
uint32_t signature;
uint32_t version;
uint32_t hash_id;
};
static int load_pack_mtimes_file(char *mtimes_file,
uint32_t num_objects,
const uint32_t **data_p, size_t *len_p)
{
int fd, ret = 0;
struct stat st;
uint32_t *data = NULL;
size_t mtimes_size, expected_size;
struct mtimes_header header;
fd = git_open(mtimes_file);
if (fd < 0) {
ret = -1;
goto cleanup;
}
if (fstat(fd, &st)) {
ret = error_errno(_("failed to read %s"), mtimes_file);
goto cleanup;
}
mtimes_size = xsize_t(st.st_size);
if (mtimes_size < MTIMES_HEADER_SIZE) {
ret = error(_("mtimes file %s is too small"), mtimes_file);
goto cleanup;
}
data = xmmap(NULL, mtimes_size, PROT_READ, MAP_PRIVATE, fd, 0);
header.signature = ntohl(data[0]);
header.version = ntohl(data[1]);
header.hash_id = ntohl(data[2]);
if (header.signature != MTIMES_SIGNATURE) {
ret = error(_("mtimes file %s has unknown signature"), mtimes_file);
goto cleanup;
}
if (header.version != 1) {
ret = error(_("mtimes file %s has unsupported version %"PRIu32),
mtimes_file, header.version);
goto cleanup;
}
if (!(header.hash_id == 1 || header.hash_id == 2)) {
ret = error(_("mtimes file %s has unsupported hash id %"PRIu32),
mtimes_file, header.hash_id);
goto cleanup;
}
expected_size = MTIMES_HEADER_SIZE;
expected_size = st_add(expected_size, st_mult(sizeof(uint32_t), num_objects));
expected_size = st_add(expected_size, 2 * (header.hash_id == 1 ? GIT_SHA1_RAWSZ : GIT_SHA256_RAWSZ));
if (mtimes_size != expected_size) {
ret = error(_("mtimes file %s is corrupt"), mtimes_file);
goto cleanup;
}
cleanup:
if (ret) {
if (data)
munmap(data, mtimes_size);
} else {
*len_p = mtimes_size;
*data_p = data;
}
close(fd);
return ret;
}
int load_pack_mtimes(struct packed_git *p)
{
char *mtimes_name = NULL;
int ret = 0;
if (!p->is_cruft)
return ret; /* not a cruft pack */
if (p->mtimes_map)
return ret; /* already loaded */
ret = open_pack_index(p);
if (ret < 0)
goto cleanup;
mtimes_name = pack_mtimes_filename(p);
ret = load_pack_mtimes_file(mtimes_name,
p->num_objects,
&p->mtimes_map,
&p->mtimes_size);
cleanup:
free(mtimes_name);
return ret;
}
uint32_t nth_packed_mtime(struct packed_git *p, uint32_t pos)
{
if (!p->mtimes_map)
BUG("pack .mtimes file not loaded for %s", p->pack_name);
if (p->num_objects <= pos)
BUG("pack .mtimes out-of-bounds (%"PRIu32" vs %"PRIu32")",
pos, p->num_objects);
return get_be32(p->mtimes_map + pos + 3);
}