[thirdparty/git.git] / pack-write.c

#include "cache.h"
#include "pack.h"
#include "csum-file.h"

void reset_pack_idx_option(struct pack_idx_option *opts)
{
	memset(opts, 0, sizeof(*opts));
	opts->version = 2;
	opts->off32_limit = 0x7fffffff;
}

static int sha1_compare(const void *_a, const void *_b)
{
	struct pack_idx_entry *a = *(struct pack_idx_entry **)_a;
	struct pack_idx_entry *b = *(struct pack_idx_entry **)_b;
	return oidcmp(&a->oid, &b->oid);
}

static int cmp_uint32(const void *a_, const void *b_)
{
	uint32_t a = *((uint32_t *)a_);
	uint32_t b = *((uint32_t *)b_);

	return (a < b) ? -1 : (a != b);
}

static int need_large_offset(off_t offset, const struct pack_idx_option *opts)
{
	uint32_t ofsval;

	if ((offset >> 31) || (opts->off32_limit < offset))
		return 1;
	if (!opts->anomaly_nr)
		return 0;
	ofsval = offset;
	return !!bsearch(&ofsval, opts->anomaly, opts->anomaly_nr,
			 sizeof(ofsval), cmp_uint32);
}

/*
 * On entry *sha1 contains the pack content SHA1 hash, on exit it is
 * the SHA1 hash of sorted object names. The objects array passed in
 * will be sorted by SHA1 on exit.
 */
const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects,
			   int nr_objects, const struct pack_idx_option *opts,
			   const unsigned char *sha1)
{
	struct sha1file *f;
	struct pack_idx_entry **sorted_by_sha, **list, **last;
	off_t last_obj_offset = 0;
	uint32_t array[256];
	int i, fd;
	uint32_t index_version;

	if (nr_objects) {
		sorted_by_sha = objects;
		list = sorted_by_sha;
		last = sorted_by_sha + nr_objects;
		for (i = 0; i < nr_objects; ++i) {
			if (objects[i]->offset > last_obj_offset)
				last_obj_offset = objects[i]->offset;
		}
		QSORT(sorted_by_sha, nr_objects, sha1_compare);
	}
	else
		sorted_by_sha = list = last = NULL;

	if (opts->flags & WRITE_IDX_VERIFY) {
		assert(index_name);
		f = sha1fd_check(index_name);
	} else {
		if (!index_name) {
			struct strbuf tmp_file = STRBUF_INIT;
			fd = odb_mkstemp(&tmp_file, "pack/tmp_idx_XXXXXX");
			index_name = strbuf_detach(&tmp_file, NULL);
		} else {
			unlink(index_name);
			fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
			if (fd < 0)
				die_errno("unable to create '%s'", index_name);
		}
		f = sha1fd(fd, index_name);
	}

	/* if last object's offset is >= 2^31 we should use index V2 */
	index_version = need_large_offset(last_obj_offset, opts) ? 2 : opts->version;

	/* index versions 2 and above need a header */
	if (index_version >= 2) {
		struct pack_idx_header hdr;
		hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
		hdr.idx_version = htonl(index_version);
		sha1write(f, &hdr, sizeof(hdr));
	}

	/*
	 * Write the first-level table (the list is sorted,
	 * but we use a 256-entry lookup to be able to avoid
	 * having to do eight extra binary search iterations).
	 */
	for (i = 0; i < 256; i++) {
		struct pack_idx_entry **next = list;
		while (next < last) {
			struct pack_idx_entry *obj = *next;
			if (obj->oid.hash[0] != i)
				break;
			next++;
		}
		array[i] = htonl(next - sorted_by_sha);
		list = next;
	}
	sha1write(f, array, 256 * 4);

	/*
	 * Write the actual SHA1 entries..
	 */
	list = sorted_by_sha;
	for (i = 0; i < nr_objects; i++) {
		struct pack_idx_entry *obj = *list++;
		if (index_version < 2) {
			uint32_t offset = htonl(obj->offset);
			sha1write(f, &offset, 4);
		}
		sha1write(f, obj->oid.hash, 20);
		if ((opts->flags & WRITE_IDX_STRICT) &&
		    (i && !oidcmp(&list[-2]->oid, &obj->oid)))
			die("The same object %s appears twice in the pack",
			    oid_to_hex(&obj->oid));
	}

	if (index_version >= 2) {
		unsigned int nr_large_offset = 0;

		/* write the crc32 table */
		list = sorted_by_sha;
		for (i = 0; i < nr_objects; i++) {
			struct pack_idx_entry *obj = *list++;
			uint32_t crc32_val = htonl(obj->crc32);
			sha1write(f, &crc32_val, 4);
		}

		/* write the 32-bit offset table */
		list = sorted_by_sha;
		for (i = 0; i < nr_objects; i++) {
			struct pack_idx_entry *obj = *list++;
			uint32_t offset;

			offset = (need_large_offset(obj->offset, opts)
				  ? (0x80000000 | nr_large_offset++)
				  : obj->offset);
			offset = htonl(offset);
			sha1write(f, &offset, 4);
		}

		/* write the large offset table */
		list = sorted_by_sha;
		while (nr_large_offset) {
			struct pack_idx_entry *obj = *list++;
			uint64_t offset = obj->offset;
			uint32_t split[2];

			if (!need_large_offset(offset, opts))
				continue;
			split[0] = htonl(offset >> 32);
			split[1] = htonl(offset & 0xffffffff);
			sha1write(f, split, 8);
			nr_large_offset--;
		}
	}

	sha1write(f, sha1, 20);
	sha1close(f, NULL, ((opts->flags & WRITE_IDX_VERIFY)
			    ? CSUM_CLOSE : CSUM_FSYNC));
	return index_name;
}

off_t write_pack_header(struct sha1file *f, uint32_t nr_entries)
{
	struct pack_header hdr;

	hdr.hdr_signature = htonl(PACK_SIGNATURE);
	hdr.hdr_version = htonl(PACK_VERSION);
	hdr.hdr_entries = htonl(nr_entries);
	sha1write(f, &hdr, sizeof(hdr));
	return sizeof(hdr);
}

/*
 * Update pack header with object_count and compute new SHA1 for pack data
 * associated to pack_fd, and write that SHA1 at the end.  That new SHA1
 * is also returned in new_pack_sha1.
 *
 * If partial_pack_sha1 is non null, then the SHA1 of the existing pack
 * (without the header update) is computed and validated against the
 * one provided in partial_pack_sha1.  The validation is performed at
 * partial_pack_offset bytes in the pack file.  The SHA1 of the remaining
 * data (i.e. from partial_pack_offset to the end) is then computed and
 * returned in partial_pack_sha1.
 *
 * Note that new_pack_sha1 is updated last, so both new_pack_sha1 and
 * partial_pack_sha1 can refer to the same buffer if the caller is not
 * interested in the resulting SHA1 of pack data above partial_pack_offset.
 */
void fixup_pack_header_footer(int pack_fd,
			 unsigned char *new_pack_sha1,
			 const char *pack_name,
			 uint32_t object_count,
			 unsigned char *partial_pack_sha1,
			 off_t partial_pack_offset)
{
	int aligned_sz, buf_sz = 8 * 1024;
	git_SHA_CTX old_sha1_ctx, new_sha1_ctx;
	struct pack_header hdr;
	char *buf;

	git_SHA1_Init(&old_sha1_ctx);
	git_SHA1_Init(&new_sha1_ctx);

	if (lseek(pack_fd, 0, SEEK_SET) != 0)
		die_errno("Failed seeking to start of '%s'", pack_name);
	if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
		die_errno("Unable to reread header of '%s'", pack_name);
	if (lseek(pack_fd, 0, SEEK_SET) != 0)
		die_errno("Failed seeking to start of '%s'", pack_name);
	git_SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));
	hdr.hdr_entries = htonl(object_count);
	git_SHA1_Update(&new_sha1_ctx, &hdr, sizeof(hdr));
	write_or_die(pack_fd, &hdr, sizeof(hdr));
	partial_pack_offset -= sizeof(hdr);

	buf = xmalloc(buf_sz);
	aligned_sz = buf_sz - sizeof(hdr);
	for (;;) {
		ssize_t m, n;
		m = (partial_pack_sha1 && partial_pack_offset < aligned_sz) ?
			partial_pack_offset : aligned_sz;
		n = xread(pack_fd, buf, m);
		if (!n)
			break;
		if (n < 0)
			die_errno("Failed to checksum '%s'", pack_name);
		git_SHA1_Update(&new_sha1_ctx, buf, n);

		aligned_sz -= n;
		if (!aligned_sz)
			aligned_sz = buf_sz;

		if (!partial_pack_sha1)
			continue;

		git_SHA1_Update(&old_sha1_ctx, buf, n);
		partial_pack_offset -= n;
		if (partial_pack_offset == 0) {
			unsigned char sha1[20];
			git_SHA1_Final(sha1, &old_sha1_ctx);
			if (hashcmp(sha1, partial_pack_sha1) != 0)
				die("Unexpected checksum for %s "
				    "(disk corruption?)", pack_name);
			/*
			 * Now let's compute the SHA1 of the remainder of the
			 * pack, which also means making partial_pack_offset
			 * big enough not to matter anymore.
			 */
			git_SHA1_Init(&old_sha1_ctx);
			partial_pack_offset = ~partial_pack_offset;
			partial_pack_offset -= MSB(partial_pack_offset, 1);
		}
	}
	free(buf);

	if (partial_pack_sha1)
		git_SHA1_Final(partial_pack_sha1, &old_sha1_ctx);
	git_SHA1_Final(new_pack_sha1, &new_sha1_ctx);
	write_or_die(pack_fd, new_pack_sha1, 20);
	fsync_or_die(pack_fd, pack_name);
}

char *index_pack_lockfile(int ip_out)
{
	char packname[46];

	/*
	 * The first thing we expect from index-pack's output
	 * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
	 * %40s is the newly created pack SHA1 name.  In the "keep"
	 * case, we need it to remove the corresponding .keep file
	 * later on.  If we don't get that then tough luck with it.
	 */
	if (read_in_full(ip_out, packname, 46) == 46 && packname[45] == '\n') {
		const char *name;
		packname[45] = 0;
		if (skip_prefix(packname, "keep\t", &name))
			return xstrfmt("%s/pack/pack-%s.keep",
				       get_object_directory(), name);
	}
	return NULL;
}

/*
 * The per-object header is a pretty dense thing, which is
 *  - first byte: low four bits are "size", then three bits of "type",
 *    and the high bit is "size continues".
 *  - each byte afterwards: low seven bits are size continuation,
 *    with the high bit being "size continues"
 */
int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
				 enum object_type type, uintmax_t size)
{
	int n = 1;
	unsigned char c;

	if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
		die("bad type %d", type);

	c = (type << 4) | (size & 15);
	size >>= 4;
	while (size) {
		if (n == hdr_len)
			die("object size is too enormous to format");
		*hdr++ = c | 0x80;
		c = size & 0x7f;
		size >>= 7;
		n++;
	}
	*hdr = c;
	return n;
}

struct sha1file *create_tmp_packfile(char **pack_tmp_name)
{
	struct strbuf tmpname = STRBUF_INIT;
	int fd;

	fd = odb_mkstemp(&tmpname, "pack/tmp_pack_XXXXXX");
	*pack_tmp_name = strbuf_detach(&tmpname, NULL);
	return sha1fd(fd, *pack_tmp_name);
}

void finish_tmp_packfile(struct strbuf *name_buffer,
			 const char *pack_tmp_name,
			 struct pack_idx_entry **written_list,
			 uint32_t nr_written,
			 struct pack_idx_option *pack_idx_opts,
			 unsigned char sha1[])
{
	const char *idx_tmp_name;
	int basename_len = name_buffer->len;

	if (adjust_shared_perm(pack_tmp_name))
		die_errno("unable to make temporary pack file readable");

	idx_tmp_name = write_idx_file(NULL, written_list, nr_written,
				      pack_idx_opts, sha1);
	if (adjust_shared_perm(idx_tmp_name))
		die_errno("unable to make temporary index file readable");

	strbuf_addf(name_buffer, "%s.pack", sha1_to_hex(sha1));

	if (rename(pack_tmp_name, name_buffer->buf))
		die_errno("unable to rename temporary pack file");

	strbuf_setlen(name_buffer, basename_len);

	strbuf_addf(name_buffer, "%s.idx", sha1_to_hex(sha1));
	if (rename(idx_tmp_name, name_buffer->buf))
		die_errno("unable to rename temporary index file");

	strbuf_setlen(name_buffer, basename_len);

	free((void *)idx_tmp_name);
}
Commit	Line	Data
8b0eca7c DH	1	#include "cache.h"
8b0eca7c DH	2	#include "pack.h"
aa7e44bf GB	3	#include "csum-file.h"
aa7e44bf GB	4
ebcfb379 JH	5	void reset_pack_idx_option(struct pack_idx_option *opts)
	6	{
	7	memset(opts, 0, sizeof(*opts));
	8	opts->version = 2;
	9	opts->off32_limit = 0x7fffffff;
	10	}
aa7e44bf GB	11
	12	static int sha1_compare(const void _a, const void _b)
	13	{
	14	struct pack_idx_entry a = (struct pack_idx_entry **)_a;
	15	struct pack_idx_entry b = (struct pack_idx_entry **)_b;
e6a492b7	16	return oidcmp(&a->oid, &b->oid);
aa7e44bf GB	17	}
aa7e44bf GB	18
3c9fc074 JH	19	static int cmp_uint32(const void a_, const void b_)
	20	{
	21	uint32_t a = ((uint32_t )a_);
	22	uint32_t b = ((uint32_t )b_);
	23
	24	return (a < b) ? -1 : (a != b);
	25	}
	26
fb956c1f JH	27	static int need_large_offset(off_t offset, const struct pack_idx_option *opts)
fb956c1f JH	28	{
3c9fc074 JH	29	uint32_t ofsval;
	30
	31	if ((offset >> 31) \|\| (opts->off32_limit < offset))
	32	return 1;
	33	if (!opts->anomaly_nr)
	34	return 0;
	35	ofsval = offset;
	36	return !!bsearch(&ofsval, opts->anomaly, opts->anomaly_nr,
	37	sizeof(ofsval), cmp_uint32);
fb956c1f JH	38	}
fb956c1f JH	39
aa7e44bf GB	40	/*
	41	* On entry *sha1 contains the pack content SHA1 hash, on exit it is
	42	* the SHA1 hash of sorted object names. The objects array passed in
	43	* will be sorted by SHA1 on exit.
	44	*/
3bb72562	45	const char write_idx_file(const char index_name, struct pack_idx_entry **objects,
ebcfb379	46	int nr_objects, const struct pack_idx_option *opts,
1190a1ac	47	const unsigned char *sha1)
aa7e44bf GB	48	{
	49	struct sha1file *f;
	50	struct pack_idx_entry sorted_by_sha, list, **last;
	51	off_t last_obj_offset = 0;
	52	uint32_t array[256];
	53	int i, fd;
aa7e44bf GB	54	uint32_t index_version;
	55
	56	if (nr_objects) {
	57	sorted_by_sha = objects;
	58	list = sorted_by_sha;
	59	last = sorted_by_sha + nr_objects;
	60	for (i = 0; i < nr_objects; ++i) {
	61	if (objects[i]->offset > last_obj_offset)
	62	last_obj_offset = objects[i]->offset;
	63	}
9ed0d8d6	64	QSORT(sorted_by_sha, nr_objects, sha1_compare);
aa7e44bf GB	65	}
	66	else
	67	sorted_by_sha = list = last = NULL;
	68
e337a04d JH	69	if (opts->flags & WRITE_IDX_VERIFY) {
	70	assert(index_name);
	71	f = sha1fd_check(index_name);
aa7e44bf	72	} else {
e337a04d	73	if (!index_name) {
594fa999 JK	74	struct strbuf tmp_file = STRBUF_INIT;
	75	fd = odb_mkstemp(&tmp_file, "pack/tmp_idx_XXXXXX");
	76	index_name = strbuf_detach(&tmp_file, NULL);
e337a04d JH	77	} else {
	78	unlink(index_name);
	79	fd = open(index_name, O_CREAT\|O_EXCL\|O_WRONLY, 0600);
892e723a JK	80	if (fd < 0)
892e723a JK	81	die_errno("unable to create '%s'", index_name);
e337a04d	82	}
e337a04d	83	f = sha1fd(fd, index_name);
aa7e44bf	84	}
aa7e44bf GB	85
aa7e44bf GB	86	/* if last object's offset is >= 2^31 we should use index V2 */
fb956c1f	87	index_version = need_large_offset(last_obj_offset, opts) ? 2 : opts->version;
aa7e44bf GB	88
	89	/* index versions 2 and above need a header */
	90	if (index_version >= 2) {
	91	struct pack_idx_header hdr;
	92	hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
	93	hdr.idx_version = htonl(index_version);
	94	sha1write(f, &hdr, sizeof(hdr));
	95	}
	96
	97	/*
	98	* Write the first-level table (the list is sorted,
	99	* but we use a 256-entry lookup to be able to avoid
	100	* having to do eight extra binary search iterations).
	101	*/
	102	for (i = 0; i < 256; i++) {
	103	struct pack_idx_entry **next = list;
	104	while (next < last) {
	105	struct pack_idx_entry obj = next;
e6a492b7	106	if (obj->oid.hash[0] != i)
aa7e44bf GB	107	break;
	108	next++;
	109	}
	110	array[i] = htonl(next - sorted_by_sha);
	111	list = next;
	112	}
	113	sha1write(f, array, 256 * 4);
	114
aa7e44bf GB	115	/*
	116	* Write the actual SHA1 entries..
	117	*/
	118	list = sorted_by_sha;
	119	for (i = 0; i < nr_objects; i++) {
	120	struct pack_idx_entry obj = list++;
	121	if (index_version < 2) {
	122	uint32_t offset = htonl(obj->offset);
	123	sha1write(f, &offset, 4);
	124	}
e6a492b7	125	sha1write(f, obj->oid.hash, 20);
68be2fea	126	if ((opts->flags & WRITE_IDX_STRICT) &&
e6a492b7	127	(i && !oidcmp(&list[-2]->oid, &obj->oid)))
68be2fea	128	die("The same object %s appears twice in the pack",
e6a492b7	129	oid_to_hex(&obj->oid));
aa7e44bf GB	130	}
	131
	132	if (index_version >= 2) {
	133	unsigned int nr_large_offset = 0;
	134
	135	/* write the crc32 table */
	136	list = sorted_by_sha;
	137	for (i = 0; i < nr_objects; i++) {
	138	struct pack_idx_entry obj = list++;
	139	uint32_t crc32_val = htonl(obj->crc32);
	140	sha1write(f, &crc32_val, 4);
	141	}
	142
	143	/* write the 32-bit offset table */
	144	list = sorted_by_sha;
	145	for (i = 0; i < nr_objects; i++) {
	146	struct pack_idx_entry obj = list++;
fb956c1f JH	147	uint32_t offset;
	148
	149	offset = (need_large_offset(obj->offset, opts)
	150	? (0x80000000 \| nr_large_offset++)
	151	: obj->offset);
aa7e44bf GB	152	offset = htonl(offset);
	153	sha1write(f, &offset, 4);
	154	}
	155
	156	/* write the large offset table */
	157	list = sorted_by_sha;
	158	while (nr_large_offset) {
	159	struct pack_idx_entry obj = list++;
	160	uint64_t offset = obj->offset;
fb956c1f JH	161	uint32_t split[2];
	162
	163	if (!need_large_offset(offset, opts))
	164	continue;
	165	split[0] = htonl(offset >> 32);
	166	split[1] = htonl(offset & 0xffffffff);
	167	sha1write(f, split, 8);
	168	nr_large_offset--;
aa7e44bf GB	169	}
	170	}
	171
	172	sha1write(f, sha1, 20);
e337a04d JH	173	sha1close(f, NULL, ((opts->flags & WRITE_IDX_VERIFY)
e337a04d JH	174	? CSUM_CLOSE : CSUM_FSYNC));
aa7e44bf GB	175	return index_name;
aa7e44bf GB	176	}
8b0eca7c	177
c0ad4657 JH	178	off_t write_pack_header(struct sha1file *f, uint32_t nr_entries)
	179	{
	180	struct pack_header hdr;
	181
	182	hdr.hdr_signature = htonl(PACK_SIGNATURE);
	183	hdr.hdr_version = htonl(PACK_VERSION);
	184	hdr.hdr_entries = htonl(nr_entries);
9af270e8	185	sha1write(f, &hdr, sizeof(hdr));
c0ad4657 JH	186	return sizeof(hdr);
	187	}
	188
abeb40e5 NP	189	/*
	190	* Update pack header with object_count and compute new SHA1 for pack data
	191	* associated to pack_fd, and write that SHA1 at the end. That new SHA1
	192	* is also returned in new_pack_sha1.
	193	*
	194	* If partial_pack_sha1 is non null, then the SHA1 of the existing pack
	195	* (without the header update) is computed and validated against the
	196	* one provided in partial_pack_sha1. The validation is performed at
	197	* partial_pack_offset bytes in the pack file. The SHA1 of the remaining
	198	* data (i.e. from partial_pack_offset to the end) is then computed and
	199	* returned in partial_pack_sha1.
	200	*
	201	* Note that new_pack_sha1 is updated last, so both new_pack_sha1 and
	202	* partial_pack_sha1 can refer to the same buffer if the caller is not
	203	* interested in the resulting SHA1 of pack data above partial_pack_offset.
	204	*/
8b0eca7c	205	void fixup_pack_header_footer(int pack_fd,
abeb40e5	206	unsigned char *new_pack_sha1,
8b0eca7c	207	const char *pack_name,
abeb40e5 NP	208	uint32_t object_count,
	209	unsigned char *partial_pack_sha1,
	210	off_t partial_pack_offset)
8b0eca7c	211	{
d35825da	212	int aligned_sz, buf_sz = 8 * 1024;
9126f009	213	git_SHA_CTX old_sha1_ctx, new_sha1_ctx;
8b0eca7c DH	214	struct pack_header hdr;
	215	char *buf;
	216
9126f009 NP	217	git_SHA1_Init(&old_sha1_ctx);
9126f009 NP	218	git_SHA1_Init(&new_sha1_ctx);
abeb40e5	219
8b0eca7c	220	if (lseek(pack_fd, 0, SEEK_SET) != 0)
d824cbba	221	die_errno("Failed seeking to start of '%s'", pack_name);
8b0eca7c	222	if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
d824cbba	223	die_errno("Unable to reread header of '%s'", pack_name);
8b0eca7c	224	if (lseek(pack_fd, 0, SEEK_SET) != 0)
d824cbba	225	die_errno("Failed seeking to start of '%s'", pack_name);
9126f009	226	git_SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));
8b0eca7c	227	hdr.hdr_entries = htonl(object_count);
9126f009	228	git_SHA1_Update(&new_sha1_ctx, &hdr, sizeof(hdr));
8b0eca7c	229	write_or_die(pack_fd, &hdr, sizeof(hdr));
abeb40e5	230	partial_pack_offset -= sizeof(hdr);
8b0eca7c DH	231
8b0eca7c DH	232	buf = xmalloc(buf_sz);
d35825da	233	aligned_sz = buf_sz - sizeof(hdr);
8b0eca7c	234	for (;;) {
abeb40e5	235	ssize_t m, n;
d35825da NP	236	m = (partial_pack_sha1 && partial_pack_offset < aligned_sz) ?
d35825da NP	237	partial_pack_offset : aligned_sz;
abeb40e5	238	n = xread(pack_fd, buf, m);
8b0eca7c DH	239	if (!n)
	240	break;
	241	if (n < 0)
d824cbba	242	die_errno("Failed to checksum '%s'", pack_name);
9126f009	243	git_SHA1_Update(&new_sha1_ctx, buf, n);
abeb40e5	244
d35825da NP	245	aligned_sz -= n;
	246	if (!aligned_sz)
	247	aligned_sz = buf_sz;
	248
abeb40e5 NP	249	if (!partial_pack_sha1)
	250	continue;
	251
9126f009	252	git_SHA1_Update(&old_sha1_ctx, buf, n);
abeb40e5 NP	253	partial_pack_offset -= n;
	254	if (partial_pack_offset == 0) {
	255	unsigned char sha1[20];
9126f009	256	git_SHA1_Final(sha1, &old_sha1_ctx);
abeb40e5 NP	257	if (hashcmp(sha1, partial_pack_sha1) != 0)
	258	die("Unexpected checksum for %s "
	259	"(disk corruption?)", pack_name);
	260	/*
	261	* Now let's compute the SHA1 of the remainder of the
	262	* pack, which also means making partial_pack_offset
	263	* big enough not to matter anymore.
	264	*/
9126f009	265	git_SHA1_Init(&old_sha1_ctx);
abeb40e5 NP	266	partial_pack_offset = ~partial_pack_offset;
	267	partial_pack_offset -= MSB(partial_pack_offset, 1);
	268	}
8b0eca7c DH	269	}
	270	free(buf);
	271
abeb40e5	272	if (partial_pack_sha1)
9126f009 NP	273	git_SHA1_Final(partial_pack_sha1, &old_sha1_ctx);
9126f009 NP	274	git_SHA1_Final(new_pack_sha1, &new_sha1_ctx);
abeb40e5	275	write_or_die(pack_fd, new_pack_sha1, 20);
0c68d386	276	fsync_or_die(pack_fd, pack_name);
8b0eca7c	277	}
106764e6 SP	278
	279	char *index_pack_lockfile(int ip_out)
	280	{
106764e6 SP	281	char packname[46];
	282
	283	/*
6e180cdc	284	* The first thing we expect from index-pack's output
106764e6 SP	285	* is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
	286	* %40s is the newly created pack SHA1 name. In the "keep"
	287	* case, we need it to remove the corresponding .keep file
	288	* later on. If we don't get that then tough luck with it.
	289	*/
d7731444 RS	290	if (read_in_full(ip_out, packname, 46) == 46 && packname[45] == '\n') {
d7731444 RS	291	const char *name;
106764e6	292	packname[45] = 0;
d7731444 RS	293	if (skip_prefix(packname, "keep\t", &name))
	294	return xstrfmt("%s/pack/pack-%s.keep",
	295	get_object_directory(), name);
106764e6 SP	296	}
	297	return NULL;
	298	}
f965c525 NP	299
	300	/*
	301	* The per-object header is a pretty dense thing, which is
	302	* - first byte: low four bits are "size", then three bits of "type",
	303	* and the high bit is "size continues".
	304	* - each byte afterwards: low seven bits are size continuation,
	305	* with the high bit being "size continues"
	306	*/
7202a6fa JK	307	int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
7202a6fa JK	308	enum object_type type, uintmax_t size)
f965c525 NP	309	{
	310	int n = 1;
	311	unsigned char c;
	312
	313	if (type < OBJ_COMMIT \|\| type > OBJ_REF_DELTA)
	314	die("bad type %d", type);
	315
	316	c = (type << 4) \| (size & 15);
	317	size >>= 4;
	318	while (size) {
7202a6fa JK	319	if (n == hdr_len)
7202a6fa JK	320	die("object size is too enormous to format");
f965c525 NP	321	*hdr++ = c \| 0x80;
	322	c = size & 0x7f;
	323	size >>= 7;
	324	n++;
	325	}
	326	*hdr = c;
	327	return n;
	328	}
cdf9db3c JH	329
	330	struct sha1file create_tmp_packfile(char *pack_tmp_name)
	331	{
594fa999	332	struct strbuf tmpname = STRBUF_INIT;
cdf9db3c JH	333	int fd;
cdf9db3c JH	334
594fa999 JK	335	fd = odb_mkstemp(&tmpname, "pack/tmp_pack_XXXXXX");
594fa999 JK	336	*pack_tmp_name = strbuf_detach(&tmpname, NULL);
cdf9db3c JH	337	return sha1fd(fd, *pack_tmp_name);
cdf9db3c JH	338	}
0e990530	339
58892711	340	void finish_tmp_packfile(struct strbuf *name_buffer,
0e990530 JH	341	const char *pack_tmp_name,
	342	struct pack_idx_entry **written_list,
	343	uint32_t nr_written,
	344	struct pack_idx_option *pack_idx_opts,
	345	unsigned char sha1[])
	346	{
	347	const char *idx_tmp_name;
58892711	348	int basename_len = name_buffer->len;
0e990530 JH	349
	350	if (adjust_shared_perm(pack_tmp_name))
	351	die_errno("unable to make temporary pack file readable");
	352
	353	idx_tmp_name = write_idx_file(NULL, written_list, nr_written,
	354	pack_idx_opts, sha1);
	355	if (adjust_shared_perm(idx_tmp_name))
	356	die_errno("unable to make temporary index file readable");
	357
58892711	358	strbuf_addf(name_buffer, "%s.pack", sha1_to_hex(sha1));
0e990530	359
58892711	360	if (rename(pack_tmp_name, name_buffer->buf))
0e990530 JH	361	die_errno("unable to rename temporary pack file");
0e990530 JH	362
58892711 SH	363	strbuf_setlen(name_buffer, basename_len);
	364
	365	strbuf_addf(name_buffer, "%s.idx", sha1_to_hex(sha1));
	366	if (rename(idx_tmp_name, name_buffer->buf))
0e990530 JH	367	die_errno("unable to rename temporary index file");
0e990530 JH	368
58892711	369	strbuf_setlen(name_buffer, basename_len);
7cc8f971	370
0e990530 JH	371	free((void *)idx_tmp_name);
0e990530 JH	372	}