[thirdparty/git.git] / server-info.c

#include "cache.h"
#include "dir.h"
#include "repository.h"
#include "refs.h"
#include "object.h"
#include "commit.h"
#include "tag.h"
#include "packfile.h"
#include "object-store.h"
#include "strbuf.h"

struct update_info_ctx {
	FILE *cur_fp;
	FILE *old_fp; /* becomes NULL if it differs from cur_fp */
	struct strbuf cur_sb;
	struct strbuf old_sb;
};

static void uic_mark_stale(struct update_info_ctx *uic)
{
	fclose(uic->old_fp);
	uic->old_fp = NULL;
}

static int uic_is_stale(const struct update_info_ctx *uic)
{
	return uic->old_fp == NULL;
}

__attribute__((format (printf, 2, 3)))
static int uic_printf(struct update_info_ctx *uic, const char *fmt, ...)
{
	va_list ap;
	int ret = -1;

	va_start(ap, fmt);

	if (uic_is_stale(uic)) {
		ret = vfprintf(uic->cur_fp, fmt, ap);
	} else {
		ssize_t r;
		struct strbuf *cur = &uic->cur_sb;
		struct strbuf *old = &uic->old_sb;

		strbuf_reset(cur);
		strbuf_vinsertf(cur, 0, fmt, ap);

		strbuf_reset(old);
		strbuf_grow(old, cur->len);
		r = fread(old->buf, 1, cur->len, uic->old_fp);
		if (r != cur->len || memcmp(old->buf, cur->buf, r))
			uic_mark_stale(uic);

		if (fwrite(cur->buf, 1, cur->len, uic->cur_fp) == cur->len)
			ret = 0;
	}

	va_end(ap);

	return ret;
}

/*
 * Create the file "path" by writing to a temporary file and renaming
 * it into place. The contents of the file come from "generate", which
 * should return non-zero if it encounters an error.
 */
static int update_info_file(char *path,
			int (*generate)(struct update_info_ctx *),
			int force)
{
	char *tmp = mkpathdup("%s_XXXXXX", path);
	int ret = -1;
	int fd = -1;
	FILE *to_close;
	struct update_info_ctx uic = {
		.cur_fp = NULL,
		.old_fp = NULL,
		.cur_sb = STRBUF_INIT,
		.old_sb = STRBUF_INIT
	};

	safe_create_leading_directories(path);
	fd = git_mkstemp_mode(tmp, 0666);
	if (fd < 0)
		goto out;
	to_close = uic.cur_fp = fdopen(fd, "w");
	if (!uic.cur_fp)
		goto out;
	fd = -1;

	/* no problem on ENOENT and old_fp == NULL, it's stale, now */
	if (!force)
		uic.old_fp = fopen_or_warn(path, "r");

	/*
	 * uic_printf will compare incremental comparison against old_fp
	 * and mark uic as stale if needed
	 */
	ret = generate(&uic);
	if (ret)
		goto out;

	/* new file may be shorter than the old one, check here */
	if (!uic_is_stale(&uic)) {
		struct stat st;
		long new_len = ftell(uic.cur_fp);
		int old_fd = fileno(uic.old_fp);

		if (new_len < 0) {
			ret = -1;
			goto out;
		}
		if (fstat(old_fd, &st) || (st.st_size != (size_t)new_len))
			uic_mark_stale(&uic);
	}

	uic.cur_fp = NULL;
	if (fclose(to_close))
		goto out;

	if (uic_is_stale(&uic)) {
		if (adjust_shared_perm(tmp) < 0)
			goto out;
		if (rename(tmp, path) < 0)
			goto out;
	} else {
		unlink(tmp);
	}
	ret = 0;

out:
	if (ret) {
		error_errno("unable to update %s", path);
		if (uic.cur_fp)
			fclose(uic.cur_fp);
		else if (fd >= 0)
			close(fd);
		unlink(tmp);
	}
	free(tmp);
	if (uic.old_fp)
		fclose(uic.old_fp);
	strbuf_release(&uic.old_sb);
	strbuf_release(&uic.cur_sb);
	return ret;
}

static int add_info_ref(const char *path, const struct object_id *oid,
			int flag, void *cb_data)
{
	struct update_info_ctx *uic = cb_data;
	struct object *o = parse_object(the_repository, oid);
	if (!o)
		return -1;

	if (uic_printf(uic, "%s	%s\n", oid_to_hex(oid), path) < 0)
		return -1;

	if (o->type == OBJ_TAG) {
		o = deref_tag(the_repository, o, path, 0);
		if (o)
			if (uic_printf(uic, "%s	%s^{}\n",
				oid_to_hex(&o->oid), path) < 0)
				return -1;
	}
	return 0;
}

static int generate_info_refs(struct update_info_ctx *uic)
{
	return for_each_ref(add_info_ref, uic);
}

static int update_info_refs(int force)
{
	char *path = git_pathdup("info/refs");
	int ret = update_info_file(path, generate_info_refs, force);
	free(path);
	return ret;
}

/* packs */
static struct pack_info {
	struct packed_git *p;
	int old_num;
	int new_num;
} **info;
static int num_pack;

static struct pack_info *find_pack_by_name(const char *name)
{
	int i;
	for (i = 0; i < num_pack; i++) {
		struct packed_git *p = info[i]->p;
		if (!strcmp(pack_basename(p), name))
			return info[i];
	}
	return NULL;
}

/* Returns non-zero when we detect that the info in the
 * old file is useless.
 */
static int parse_pack_def(const char *packname, int old_cnt)
{
	struct pack_info *i = find_pack_by_name(packname);
	if (i) {
		i->old_num = old_cnt;
		return 0;
	}
	else {
		/* The file describes a pack that is no longer here */
		return 1;
	}
}

/* Returns non-zero when we detect that the info in the
 * old file is useless.
 */
static int read_pack_info_file(const char *infofile)
{
	FILE *fp;
	struct strbuf line = STRBUF_INIT;
	int old_cnt = 0;
	int stale = 1;

	fp = fopen_or_warn(infofile, "r");
	if (!fp)
		return 1; /* nonexistent is not an error. */

	while (strbuf_getline(&line, fp) != EOF) {
		const char *arg;

		if (!line.len)
			continue;

		if (skip_prefix(line.buf, "P ", &arg)) {
			/* P name */
			if (parse_pack_def(arg, old_cnt++))
				goto out_stale;
		} else if (line.buf[0] == 'D') {
			/* we used to emit D but that was misguided. */
			goto out_stale;
		} else if (line.buf[0] == 'T') {
			/* we used to emit T but nobody uses it. */
			goto out_stale;
		} else {
			error("unrecognized: %s", line.buf);
		}
	}
	stale = 0;

 out_stale:
	strbuf_release(&line);
	fclose(fp);
	return stale;
}

static int compare_info(const void *a_, const void *b_)
{
	struct pack_info *const *a = a_;
	struct pack_info *const *b = b_;

	if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
		/* Keep the order in the original */
		return (*a)->old_num - (*b)->old_num;
	else if (0 <= (*a)->old_num)
		/* Only A existed in the original so B is obviously newer */
		return -1;
	else if (0 <= (*b)->old_num)
		/* The other way around. */
		return 1;

	/* then it does not matter but at least keep the comparison stable */
	if ((*a)->p == (*b)->p)
		return 0;
	else if ((*a)->p < (*b)->p)
		return -1;
	else
		return 1;
}

static void init_pack_info(const char *infofile, int force)
{
	struct packed_git *p;
	int stale;
	int i;
	size_t alloc = 0;

	for (p = get_all_packs(the_repository); p; p = p->next) {
		/* we ignore things on alternate path since they are
		 * not available to the pullers in general.
		 */
		if (!p->pack_local || !file_exists(p->pack_name))
			continue;

		i = num_pack++;
		ALLOC_GROW(info, num_pack, alloc);
		CALLOC_ARRAY(info[i], 1);
		info[i]->p = p;
		info[i]->old_num = -1;
	}

	if (infofile && !force)
		stale = read_pack_info_file(infofile);
	else
		stale = 1;

	for (i = 0; i < num_pack; i++)
		if (stale)
			info[i]->old_num = -1;

	/* renumber them */
	QSORT(info, num_pack, compare_info);
	for (i = 0; i < num_pack; i++)
		info[i]->new_num = i;
}

static void free_pack_info(void)
{
	int i;
	for (i = 0; i < num_pack; i++)
		free(info[i]);
	free(info);
}

static int write_pack_info_file(struct update_info_ctx *uic)
{
	int i;
	for (i = 0; i < num_pack; i++) {
		if (uic_printf(uic, "P %s\n", pack_basename(info[i]->p)) < 0)
			return -1;
	}
	if (uic_printf(uic, "\n") < 0)
		return -1;
	return 0;
}

static int update_info_packs(int force)
{
	char *infofile = mkpathdup("%s/info/packs", get_object_directory());
	int ret;

	init_pack_info(infofile, force);
	ret = update_info_file(infofile, write_pack_info_file, force);
	free_pack_info();
	free(infofile);
	return ret;
}

/* public */
int update_server_info(int force)
{
	/* We would add more dumb-server support files later,
	 * including index of available pack files and their
	 * intended audiences.
	 */
	int errs = 0;

	errs = errs | update_info_refs(force);
	errs = errs | update_info_packs(force);

	/* remove leftover rev-cache file if there is any */
	unlink_or_warn(git_path("info/rev-cache"));

	return errs;
}
Commit	Line	Data
8f3f9b09	1	#include "cache.h"
e941c48d	2	#include "dir.h"
a80d72db	3	#include "repository.h"
8f3f9b09 JH	4	#include "refs.h"
	5	#include "object.h"
	6	#include "commit.h"
b614e3d7	7	#include "tag.h"
0abe14f6	8	#include "packfile.h"
a80d72db	9	#include "object-store.h"
f4f476b6 EW	10	#include "strbuf.h"
	11
	12	struct update_info_ctx {
	13	FILE *cur_fp;
	14	FILE old_fp; / becomes NULL if it differs from cur_fp */
	15	struct strbuf cur_sb;
	16	struct strbuf old_sb;
	17	};
	18
	19	static void uic_mark_stale(struct update_info_ctx *uic)
	20	{
	21	fclose(uic->old_fp);
	22	uic->old_fp = NULL;
	23	}
	24
	25	static int uic_is_stale(const struct update_info_ctx *uic)
	26	{
	27	return uic->old_fp == NULL;
	28	}
	29
48ca53ca	30	__attribute__((format (printf, 2, 3)))
f4f476b6 EW	31	static int uic_printf(struct update_info_ctx uic, const char fmt, ...)
	32	{
	33	va_list ap;
	34	int ret = -1;
	35
	36	va_start(ap, fmt);
	37
	38	if (uic_is_stale(uic)) {
	39	ret = vfprintf(uic->cur_fp, fmt, ap);
	40	} else {
	41	ssize_t r;
	42	struct strbuf *cur = &uic->cur_sb;
	43	struct strbuf *old = &uic->old_sb;
	44
	45	strbuf_reset(cur);
	46	strbuf_vinsertf(cur, 0, fmt, ap);
	47
	48	strbuf_reset(old);
	49	strbuf_grow(old, cur->len);
	50	r = fread(old->buf, 1, cur->len, uic->old_fp);
	51	if (r != cur->len \|\| memcmp(old->buf, cur->buf, r))
	52	uic_mark_stale(uic);
	53
	54	if (fwrite(cur->buf, 1, cur->len, uic->cur_fp) == cur->len)
	55	ret = 0;
	56	}
	57
	58	va_end(ap);
	59
	60	return ret;
	61	}
8f3f9b09	62
d38379ec JK	63	/*
	64	* Create the file "path" by writing to a temporary file and renaming
	65	* it into place. The contents of the file come from "generate", which
	66	* should return non-zero if it encounters an error.
	67	*/
f4f476b6 EW	68	static int update_info_file(char *path,
	69	int (generate)(struct update_info_ctx ),
	70	int force)
d38379ec JK	71	{
	72	char *tmp = mkpathdup("%s_XXXXXX", path);
	73	int ret = -1;
	74	int fd = -1;
f4f476b6 EW	75	FILE *to_close;
	76	struct update_info_ctx uic = {
	77	.cur_fp = NULL,
	78	.old_fp = NULL,
	79	.cur_sb = STRBUF_INIT,
	80	.old_sb = STRBUF_INIT
	81	};
d38379ec JK	82
d38379ec JK	83	safe_create_leading_directories(path);
d91175b2	84	fd = git_mkstemp_mode(tmp, 0666);
d38379ec JK	85	if (fd < 0)
d38379ec JK	86	goto out;
f4f476b6 EW	87	to_close = uic.cur_fp = fdopen(fd, "w");
f4f476b6 EW	88	if (!uic.cur_fp)
d38379ec	89	goto out;
fa1912c8	90	fd = -1;
f4f476b6 EW	91
	92	/* no problem on ENOENT and old_fp == NULL, it's stale, now */
	93	if (!force)
	94	uic.old_fp = fopen_or_warn(path, "r");
	95
	96	/*
15beaaa3	97	* uic_printf will compare incremental comparison against old_fp
f4f476b6 EW	98	* and mark uic as stale if needed
	99	*/
	100	ret = generate(&uic);
d38379ec JK	101	if (ret)
d38379ec JK	102	goto out;
f4f476b6 EW	103
	104	/* new file may be shorter than the old one, check here */
	105	if (!uic_is_stale(&uic)) {
	106	struct stat st;
	107	long new_len = ftell(uic.cur_fp);
	108	int old_fd = fileno(uic.old_fp);
	109
	110	if (new_len < 0) {
	111	ret = -1;
	112	goto out;
	113	}
	114	if (fstat(old_fd, &st) \|\| (st.st_size != (size_t)new_len))
	115	uic_mark_stale(&uic);
	116	}
	117
	118	uic.cur_fp = NULL;
fa1912c8	119	if (fclose(to_close))
d38379ec	120	goto out;
f4f476b6 EW	121
	122	if (uic_is_stale(&uic)) {
	123	if (adjust_shared_perm(tmp) < 0)
	124	goto out;
	125	if (rename(tmp, path) < 0)
	126	goto out;
	127	} else {
	128	unlink(tmp);
	129	}
d38379ec JK	130	ret = 0;
	131
	132	out:
	133	if (ret) {
02382f51	134	error_errno("unable to update %s", path);
f4f476b6 EW	135	if (uic.cur_fp)
f4f476b6 EW	136	fclose(uic.cur_fp);
d38379ec JK	137	else if (fd >= 0)
	138	close(fd);
	139	unlink(tmp);
	140	}
	141	free(tmp);
f4f476b6 EW	142	if (uic.old_fp)
	143	fclose(uic.old_fp);
	144	strbuf_release(&uic.old_sb);
	145	strbuf_release(&uic.cur_sb);
d38379ec JK	146	return ret;
d38379ec JK	147	}
8f3f9b09	148
e2b0bcdf MH	149	static int add_info_ref(const char path, const struct object_id oid,
e2b0bcdf MH	150	int flag, void *cb_data)
8f3f9b09	151	{
f4f476b6	152	struct update_info_ctx *uic = cb_data;
109cd76d	153	struct object *o = parse_object(the_repository, oid);
76f8a302 SP	154	if (!o)
76f8a302 SP	155	return -1;
f6b42a81	156
f4f476b6	157	if (uic_printf(uic, "%s %s\n", oid_to_hex(oid), path) < 0)
d38379ec JK	158	return -1;
d38379ec JK	159
1974632c	160	if (o->type == OBJ_TAG) {
a74093da	161	o = deref_tag(the_repository, o, path, 0);
9534f40b	162	if (o)
f4f476b6	163	if (uic_printf(uic, "%s %s^{}\n",
f2fd0760	164	oid_to_hex(&o->oid), path) < 0)
d38379ec	165	return -1;
f6b42a81	166	}
8f3f9b09 JH	167	return 0;
	168	}
	169
f4f476b6	170	static int generate_info_refs(struct update_info_ctx *uic)
d38379ec	171	{
f4f476b6	172	return for_each_ref(add_info_ref, uic);
d38379ec JK	173	}
d38379ec JK	174
f4f476b6	175	static int update_info_refs(int force)
8f3f9b09	176	{
d38379ec	177	char *path = git_pathdup("info/refs");
f4f476b6	178	int ret = update_info_file(path, generate_info_refs, force);
d38379ec JK	179	free(path);
d38379ec JK	180	return ret;
8f3f9b09 JH	181	}
	182
	183	/* packs */
4d8fa916	184	static struct pack_info {
8f3f9b09 JH	185	struct packed_git *p;
	186	int old_num;
	187	int new_num;
8f3f9b09 JH	188	} **info;
8f3f9b09 JH	189	static int num_pack;
8f3f9b09	190
8f3f9b09 JH	191	static struct pack_info find_pack_by_name(const char name)
	192	{
	193	int i;
	194	for (i = 0; i < num_pack; i++) {
	195	struct packed_git *p = info[i]->p;
b9fb142e	196	if (!strcmp(pack_basename(p), name))
8f3f9b09 JH	197	return info[i];
	198	}
	199	return NULL;
	200	}
	201
8f3f9b09 JH	202	/* Returns non-zero when we detect that the info in the
	203	* old file is useless.
	204	*/
b83a3089	205	static int parse_pack_def(const char *packname, int old_cnt)
8f3f9b09	206	{
b83a3089	207	struct pack_info *i = find_pack_by_name(packname);
8f3f9b09 JH	208	if (i) {
	209	i->old_num = old_cnt;
	210	return 0;
	211	}
	212	else {
6f42f89c	213	/* The file describes a pack that is no longer here */
8f3f9b09 JH	214	return 1;
	215	}
	216	}
	217
8f3f9b09 JH	218	/* Returns non-zero when we detect that the info in the
	219	* old file is useless.
	220	*/
	221	static int read_pack_info_file(const char *infofile)
	222	{
	223	FILE *fp;
4ecbd649	224	struct strbuf line = STRBUF_INIT;
8f3f9b09	225	int old_cnt = 0;
965cc517	226	int stale = 1;
8f3f9b09	227
e9d983f1	228	fp = fopen_or_warn(infofile, "r");
8f3f9b09	229	if (!fp)
addf88e4	230	return 1; /* nonexistent is not an error. */
8f3f9b09	231
4ecbd649	232	while (strbuf_getline(&line, fp) != EOF) {
b83a3089	233	const char *arg;
8ac4838a	234
4ecbd649	235	if (!line.len)
8ac4838a	236	continue;
8f3f9b09	237
4ecbd649	238	if (skip_prefix(line.buf, "P ", &arg)) {
b83a3089 JK	239	/* P name */
b83a3089 JK	240	if (parse_pack_def(arg, old_cnt++))
8f3f9b09	241	goto out_stale;
4ecbd649	242	} else if (line.buf[0] == 'D') {
b83a3089	243	/* we used to emit D but that was misguided. */
3e15c67c	244	goto out_stale;
4ecbd649	245	} else if (line.buf[0] == 'T') {
b83a3089 JK	246	/* we used to emit T but nobody uses it. */
	247	goto out_stale;
	248	} else {
4ecbd649	249	error("unrecognized: %s", line.buf);
8f3f9b09 JH	250	}
8f3f9b09 JH	251	}
965cc517 JK	252	stale = 0;
965cc517 JK	253
8f3f9b09	254	out_stale:
4ecbd649	255	strbuf_release(&line);
8f3f9b09	256	fclose(fp);
965cc517	257	return stale;
8f3f9b09 JH	258	}
8f3f9b09 JH	259
8f3f9b09 JH	260	static int compare_info(const void a_, const void b_)
8f3f9b09 JH	261	{
4b25d091 FC	262	struct pack_info const a = a_;
4b25d091 FC	263	struct pack_info const b = b_;
8f3f9b09 JH	264
	265	if (0 <= (a)->old_num && 0 <= (b)->old_num)
	266	/* Keep the order in the original */
	267	return (a)->old_num - (b)->old_num;
	268	else if (0 <= (*a)->old_num)
	269	/* Only A existed in the original so B is obviously newer */
	270	return -1;
	271	else if (0 <= (*b)->old_num)
	272	/* The other way around. */
	273	return 1;
	274
d5eac498	275	/* then it does not matter but at least keep the comparison stable */
2dee5816 JH	276	if ((a)->p == (b)->p)
	277	return 0;
	278	else if ((a)->p < (b)->p)
	279	return -1;
	280	else
	281	return 1;
8f3f9b09 JH	282	}
	283
	284	static void init_pack_info(const char *infofile, int force)
	285	{
	286	struct packed_git *p;
	287	int stale;
e941c48d EW	288	int i;
e941c48d EW	289	size_t alloc = 0;
8f3f9b09	290
454ea2e4	291	for (p = get_all_packs(the_repository); p; p = p->next) {
8f3f9b09 JH	292	/* we ignore things on alternate path since they are
	293	* not available to the pullers in general.
	294	*/
e941c48d	295	if (!p->pack_local \|\| !file_exists(p->pack_name))
8f3f9b09	296	continue;
e941c48d EW	297
	298	i = num_pack++;
	299	ALLOC_GROW(info, num_pack, alloc);
ca56dadb	300	CALLOC_ARRAY(info[i], 1);
8f3f9b09 JH	301	info[i]->p = p;
8f3f9b09 JH	302	info[i]->old_num = -1;
8f3f9b09 JH	303	}
	304
	305	if (infofile && !force)
	306	stale = read_pack_info_file(infofile);
	307	else
	308	stale = 1;
	309
910710bb	310	for (i = 0; i < num_pack; i++)
910710bb	311	if (stale)
8f3f9b09	312	info[i]->old_num = -1;
8f3f9b09	313
6f42f89c	314	/* renumber them */
9ed0d8d6	315	QSORT(info, num_pack, compare_info);
8f3f9b09 JH	316	for (i = 0; i < num_pack; i++)
8f3f9b09 JH	317	info[i]->new_num = i;
8f3f9b09 JH	318	}
8f3f9b09 JH	319
3907a407 JK	320	static void free_pack_info(void)
	321	{
	322	int i;
	323	for (i = 0; i < num_pack; i++)
	324	free(info[i]);
	325	free(info);
	326	}
	327
f4f476b6	328	static int write_pack_info_file(struct update_info_ctx *uic)
8f3f9b09	329	{
3e15c67c	330	int i;
d38379ec	331	for (i = 0; i < num_pack; i++) {
f4f476b6	332	if (uic_printf(uic, "P %s\n", pack_basename(info[i]->p)) < 0)
d38379ec JK	333	return -1;
d38379ec JK	334	}
f4f476b6	335	if (uic_printf(uic, "\n") < 0)
d38379ec JK	336	return -1;
d38379ec JK	337	return 0;
8f3f9b09 JH	338	}
	339
	340	static int update_info_packs(int force)
	341	{
d38379ec JK	342	char *infofile = mkpathdup("%s/info/packs", get_object_directory());
d38379ec JK	343	int ret;
8f3f9b09 JH	344
8f3f9b09 JH	345	init_pack_info(infofile, force);
f4f476b6	346	ret = update_info_file(infofile, write_pack_info_file, force);
3907a407	347	free_pack_info();
d38379ec JK	348	free(infofile);
d38379ec JK	349	return ret;
8f3f9b09 JH	350	}
8f3f9b09 JH	351
8f3f9b09 JH	352	/* public */
	353	int update_server_info(int force)
	354	{
	355	/* We would add more dumb-server support files later,
	356	* including index of available pack files and their
	357	* intended audiences.
	358	*/
	359	int errs = 0;
	360
f4f476b6	361	errs = errs \| update_info_refs(force);
8f3f9b09	362	errs = errs \| update_info_packs(force);
8f3f9b09	363
6f42f89c	364	/* remove leftover rev-cache file if there is any */
691f1a28	365	unlink_or_warn(git_path("info/rev-cache"));
6f42f89c	366
8f3f9b09 JH	367	return errs;
8f3f9b09 JH	368	}