git

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