[thirdparty/git.git] / archive-tar.c

/*
 * Copyright (c) 2005, 2006 Rene Scharfe
 */
#include "cache.h"
#include "config.h"
#include "tar.h"
#include "archive.h"
#include "streaming.h"
#include "run-command.h"

#define RECORDSIZE	(512)
#define BLOCKSIZE	(RECORDSIZE * 20)

static char block[BLOCKSIZE];
static unsigned long offset;

static int tar_umask = 002;

static int write_tar_filter_archive(const struct archiver *ar,
				    struct archiver_args *args);

/*
 * This is the max value that a ustar size header can specify, as it is fixed
 * at 11 octal digits. POSIX specifies that we switch to extended headers at
 * this size.
 *
 * Likewise for the mtime (which happens to use a buffer of the same size).
 */
#if ULONG_MAX == 0xFFFFFFFF
#define USTAR_MAX_SIZE ULONG_MAX
#define USTAR_MAX_MTIME ULONG_MAX
#else
#define USTAR_MAX_SIZE 077777777777UL
#define USTAR_MAX_MTIME 077777777777UL
#endif

/* writes out the whole block, but only if it is full */
static void write_if_needed(void)
{
	if (offset == BLOCKSIZE) {
		write_or_die(1, block, BLOCKSIZE);
		offset = 0;
	}
}

/*
 * queues up writes, so that all our write(2) calls write exactly one
 * full block; pads writes to RECORDSIZE
 */
static void do_write_blocked(const void *data, unsigned long size)
{
	const char *buf = data;

	if (offset) {
		unsigned long chunk = BLOCKSIZE - offset;
		if (size < chunk)
			chunk = size;
		memcpy(block + offset, buf, chunk);
		size -= chunk;
		offset += chunk;
		buf += chunk;
		write_if_needed();
	}
	while (size >= BLOCKSIZE) {
		write_or_die(1, buf, BLOCKSIZE);
		size -= BLOCKSIZE;
		buf += BLOCKSIZE;
	}
	if (size) {
		memcpy(block + offset, buf, size);
		offset += size;
	}
}

static void finish_record(void)
{
	unsigned long tail;
	tail = offset % RECORDSIZE;
	if (tail)  {
		memset(block + offset, 0, RECORDSIZE - tail);
		offset += RECORDSIZE - tail;
	}
	write_if_needed();
}

static void write_blocked(const void *data, unsigned long size)
{
	do_write_blocked(data, size);
	finish_record();
}

/*
 * The end of tar archives is marked by 2*512 nul bytes and after that
 * follows the rest of the block (if any).
 */
static void write_trailer(void)
{
	int tail = BLOCKSIZE - offset;
	memset(block + offset, 0, tail);
	write_or_die(1, block, BLOCKSIZE);
	if (tail < 2 * RECORDSIZE) {
		memset(block, 0, offset);
		write_or_die(1, block, BLOCKSIZE);
	}
}

/*
 * queues up writes, so that all our write(2) calls write exactly one
 * full block; pads writes to RECORDSIZE
 */
static int stream_blocked(const unsigned char *sha1)
{
	struct git_istream *st;
	enum object_type type;
	unsigned long sz;
	char buf[BLOCKSIZE];
	ssize_t readlen;

	st = open_istream(sha1, &type, &sz, NULL);
	if (!st)
		return error("cannot stream blob %s", sha1_to_hex(sha1));
	for (;;) {
		readlen = read_istream(st, buf, sizeof(buf));
		if (readlen <= 0)
			break;
		do_write_blocked(buf, readlen);
	}
	close_istream(st);
	if (!readlen)
		finish_record();
	return readlen;
}

/*
 * pax extended header records have the format "%u %s=%s\n".  %u contains
 * the size of the whole string (including the %u), the first %s is the
 * keyword, the second one is the value.  This function constructs such a
 * string and appends it to a struct strbuf.
 */
static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
                                     const char *value, unsigned int valuelen)
{
	int len, tmp;

	/* "%u %s=%s\n" */
	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
	for (tmp = len; tmp > 9; tmp /= 10)
		len++;

	strbuf_grow(sb, len);
	strbuf_addf(sb, "%u %s=", len, keyword);
	strbuf_add(sb, value, valuelen);
	strbuf_addch(sb, '\n');
}

/*
 * Like strbuf_append_ext_header, but for numeric values.
 */
static void strbuf_append_ext_header_uint(struct strbuf *sb,
					  const char *keyword,
					  uintmax_t value)
{
	char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
	int len;

	len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
	strbuf_append_ext_header(sb, keyword, buf, len);
}

static unsigned int ustar_header_chksum(const struct ustar_header *header)
{
	const unsigned char *p = (const unsigned char *)header;
	unsigned int chksum = 0;
	while (p < (const unsigned char *)header->chksum)
		chksum += *p++;
	chksum += sizeof(header->chksum) * ' ';
	p += sizeof(header->chksum);
	while (p < (const unsigned char *)header + sizeof(struct ustar_header))
		chksum += *p++;
	return chksum;
}

static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
{
	size_t i = pathlen;
	if (i > 1 && path[i - 1] == '/')
		i--;
	if (i > maxlen)
		i = maxlen;
	do {
		i--;
	} while (i > 0 && path[i] != '/');
	return i;
}

static void prepare_header(struct archiver_args *args,
			   struct ustar_header *header,
			   unsigned int mode, unsigned long size)
{
	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
	xsnprintf(header->size, sizeof(header->size), "%011lo", S_ISREG(mode) ? size : 0);
	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);

	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
	strlcpy(header->uname, "root", sizeof(header->uname));
	strlcpy(header->gname, "root", sizeof(header->gname));
	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);

	memcpy(header->magic, "ustar", 6);
	memcpy(header->version, "00", 2);

	xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
}

static void write_extended_header(struct archiver_args *args,
				  const unsigned char *sha1,
				  const void *buffer, unsigned long size)
{
	struct ustar_header header;
	unsigned int mode;
	memset(&header, 0, sizeof(header));
	*header.typeflag = TYPEFLAG_EXT_HEADER;
	mode = 0100666;
	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", sha1_to_hex(sha1));
	prepare_header(args, &header, mode, size);
	write_blocked(&header, sizeof(header));
	write_blocked(buffer, size);
}

static int write_tar_entry(struct archiver_args *args,
			   const unsigned char *sha1,
			   const char *path, size_t pathlen,
			   unsigned int mode)
{
	struct ustar_header header;
	struct strbuf ext_header = STRBUF_INIT;
	unsigned int old_mode = mode;
	unsigned long size, size_in_header;
	void *buffer;
	int err = 0;

	memset(&header, 0, sizeof(header));

	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
		*header.typeflag = TYPEFLAG_DIR;
		mode = (mode | 0777) & ~tar_umask;
	} else if (S_ISLNK(mode)) {
		*header.typeflag = TYPEFLAG_LNK;
		mode |= 0777;
	} else if (S_ISREG(mode)) {
		*header.typeflag = TYPEFLAG_REG;
		mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
	} else {
		return error("unsupported file mode: 0%o (SHA1: %s)",
			     mode, sha1_to_hex(sha1));
	}
	if (pathlen > sizeof(header.name)) {
		size_t plen = get_path_prefix(path, pathlen,
					      sizeof(header.prefix));
		size_t rest = pathlen - plen - 1;
		if (plen > 0 && rest <= sizeof(header.name)) {
			memcpy(header.prefix, path, plen);
			memcpy(header.name, path + plen + 1, rest);
		} else {
			xsnprintf(header.name, sizeof(header.name), "%s.data",
				  sha1_to_hex(sha1));
			strbuf_append_ext_header(&ext_header, "path",
						 path, pathlen);
		}
	} else
		memcpy(header.name, path, pathlen);

	if (S_ISREG(mode) && !args->convert &&
	    sha1_object_info(sha1, &size) == OBJ_BLOB &&
	    size > big_file_threshold)
		buffer = NULL;
	else if (S_ISLNK(mode) || S_ISREG(mode)) {
		enum object_type type;
		buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
		if (!buffer)
			return error("cannot read %s", sha1_to_hex(sha1));
	} else {
		buffer = NULL;
		size = 0;
	}

	if (S_ISLNK(mode)) {
		if (size > sizeof(header.linkname)) {
			xsnprintf(header.linkname, sizeof(header.linkname),
				  "see %s.paxheader", sha1_to_hex(sha1));
			strbuf_append_ext_header(&ext_header, "linkpath",
			                         buffer, size);
		} else
			memcpy(header.linkname, buffer, size);
	}

	size_in_header = size;
	if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
		size_in_header = 0;
		strbuf_append_ext_header_uint(&ext_header, "size", size);
	}

	prepare_header(args, &header, mode, size_in_header);

	if (ext_header.len > 0) {
		write_extended_header(args, sha1, ext_header.buf,
				      ext_header.len);
	}
	strbuf_release(&ext_header);
	write_blocked(&header, sizeof(header));
	if (S_ISREG(mode) && size > 0) {
		if (buffer)
			write_blocked(buffer, size);
		else
			err = stream_blocked(sha1);
	}
	free(buffer);
	return err;
}

static void write_global_extended_header(struct archiver_args *args)
{
	const unsigned char *sha1 = args->commit_sha1;
	struct strbuf ext_header = STRBUF_INIT;
	struct ustar_header header;
	unsigned int mode;

	if (sha1)
		strbuf_append_ext_header(&ext_header, "comment",
					 sha1_to_hex(sha1), 40);
	if (args->time > USTAR_MAX_MTIME) {
		strbuf_append_ext_header_uint(&ext_header, "mtime",
					      args->time);
		args->time = USTAR_MAX_MTIME;
	}

	if (!ext_header.len)
		return;

	memset(&header, 0, sizeof(header));
	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
	mode = 0100666;
	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
	prepare_header(args, &header, mode, ext_header.len);
	write_blocked(&header, sizeof(header));
	write_blocked(ext_header.buf, ext_header.len);
	strbuf_release(&ext_header);
}

static struct archiver **tar_filters;
static int nr_tar_filters;
static int alloc_tar_filters;

static struct archiver *find_tar_filter(const char *name, int len)
{
	int i;
	for (i = 0; i < nr_tar_filters; i++) {
		struct archiver *ar = tar_filters[i];
		if (!strncmp(ar->name, name, len) && !ar->name[len])
			return ar;
	}
	return NULL;
}

static int tar_filter_config(const char *var, const char *value, void *data)
{
	struct archiver *ar;
	const char *name;
	const char *type;
	int namelen;

	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
		return 0;

	ar = find_tar_filter(name, namelen);
	if (!ar) {
		ar = xcalloc(1, sizeof(*ar));
		ar->name = xmemdupz(name, namelen);
		ar->write_archive = write_tar_filter_archive;
		ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
		ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
		tar_filters[nr_tar_filters++] = ar;
	}

	if (!strcmp(type, "command")) {
		if (!value)
			return config_error_nonbool(var);
		free(ar->data);
		ar->data = xstrdup(value);
		return 0;
	}
	if (!strcmp(type, "remote")) {
		if (git_config_bool(var, value))
			ar->flags |= ARCHIVER_REMOTE;
		else
			ar->flags &= ~ARCHIVER_REMOTE;
		return 0;
	}

	return 0;
}

static int git_tar_config(const char *var, const char *value, void *cb)
{
	if (!strcmp(var, "tar.umask")) {
		if (value && !strcmp(value, "user")) {
			tar_umask = umask(0);
			umask(tar_umask);
		} else {
			tar_umask = git_config_int(var, value);
		}
		return 0;
	}

	return tar_filter_config(var, value, cb);
}

static int write_tar_archive(const struct archiver *ar,
			     struct archiver_args *args)
{
	int err = 0;

	write_global_extended_header(args);
	err = write_archive_entries(args, write_tar_entry);
	if (!err)
		write_trailer();
	return err;
}

static int write_tar_filter_archive(const struct archiver *ar,
				    struct archiver_args *args)
{
	struct strbuf cmd = STRBUF_INIT;
	struct child_process filter = CHILD_PROCESS_INIT;
	const char *argv[2];
	int r;

	if (!ar->data)
		die("BUG: tar-filter archiver called with no filter defined");

	strbuf_addstr(&cmd, ar->data);
	if (args->compression_level >= 0)
		strbuf_addf(&cmd, " -%d", args->compression_level);

	argv[0] = cmd.buf;
	argv[1] = NULL;
	filter.argv = argv;
	filter.use_shell = 1;
	filter.in = -1;

	if (start_command(&filter) < 0)
		die_errno("unable to start '%s' filter", argv[0]);
	close(1);
	if (dup2(filter.in, 1) < 0)
		die_errno("unable to redirect descriptor");
	close(filter.in);

	r = write_tar_archive(ar, args);

	close(1);
	if (finish_command(&filter) != 0)
		die("'%s' filter reported error", argv[0]);

	strbuf_release(&cmd);
	return r;
}

static struct archiver tar_archiver = {
	"tar",
	write_tar_archive,
	ARCHIVER_REMOTE
};

void init_tar_archiver(void)
{
	int i;
	register_archiver(&tar_archiver);

	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
	tar_filter_config("tar.tgz.remote", "true", NULL);
	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
	tar_filter_config("tar.tar.gz.remote", "true", NULL);
	git_config(git_tar_config, NULL);
	for (i = 0; i < nr_tar_filters; i++) {
		/* omit any filters that never had a command configured */
		if (tar_filters[i]->data)
			register_archiver(tar_filters[i]);
	}
}
Commit	Line	Data
3d74982f RS	1	/*
	2	* Copyright (c) 2005, 2006 Rene Scharfe
	3	*/
3d74982f	4	#include "cache.h"
b2141fc1	5	#include "config.h"
3d74982f	6	#include "tar.h"
3d74982f	7	#include "archive.h"
5544049d	8	#include "streaming.h"
767cf457	9	#include "run-command.h"
3d74982f RS	10
	11	#define RECORDSIZE (512)
	12	#define BLOCKSIZE (RECORDSIZE * 20)
	13
	14	static char block[BLOCKSIZE];
	15	static unsigned long offset;
	16
f08b3b0e	17	static int tar_umask = 002;
3d74982f	18
767cf457 JK	19	static int write_tar_filter_archive(const struct archiver *ar,
	20	struct archiver_args *args);
	21
d1657b57 JK	22	/*
	23	* This is the max value that a ustar size header can specify, as it is fixed
	24	* at 11 octal digits. POSIX specifies that we switch to extended headers at
	25	* this size.
6e8e0991 JK	26	*
6e8e0991 JK	27	* Likewise for the mtime (which happens to use a buffer of the same size).
d1657b57	28	*/
29493589 JH	29	#if ULONG_MAX == 0xFFFFFFFF
	30	#define USTAR_MAX_SIZE ULONG_MAX
	31	#define USTAR_MAX_MTIME ULONG_MAX
	32	#else
d1657b57	33	#define USTAR_MAX_SIZE 077777777777UL
6e8e0991	34	#define USTAR_MAX_MTIME 077777777777UL
29493589	35	#endif
d1657b57	36
3d74982f RS	37	/* writes out the whole block, but only if it is full */
	38	static void write_if_needed(void)
	39	{
	40	if (offset == BLOCKSIZE) {
	41	write_or_die(1, block, BLOCKSIZE);
	42	offset = 0;
	43	}
	44	}
	45
	46	/*
	47	* queues up writes, so that all our write(2) calls write exactly one
	48	* full block; pads writes to RECORDSIZE
	49	*/
5544049d	50	static void do_write_blocked(const void *data, unsigned long size)
3d74982f RS	51	{
3d74982f RS	52	const char *buf = data;
3d74982f RS	53
	54	if (offset) {
	55	unsigned long chunk = BLOCKSIZE - offset;
	56	if (size < chunk)
	57	chunk = size;
	58	memcpy(block + offset, buf, chunk);
	59	size -= chunk;
	60	offset += chunk;
	61	buf += chunk;
	62	write_if_needed();
	63	}
	64	while (size >= BLOCKSIZE) {
	65	write_or_die(1, buf, BLOCKSIZE);
	66	size -= BLOCKSIZE;
	67	buf += BLOCKSIZE;
	68	}
	69	if (size) {
	70	memcpy(block + offset, buf, size);
	71	offset += size;
	72	}
5544049d NTND	73	}
	74
	75	static void finish_record(void)
	76	{
	77	unsigned long tail;
3d74982f RS	78	tail = offset % RECORDSIZE;
	79	if (tail) {
	80	memset(block + offset, 0, RECORDSIZE - tail);
	81	offset += RECORDSIZE - tail;
	82	}
	83	write_if_needed();
	84	}
	85
5544049d NTND	86	static void write_blocked(const void *data, unsigned long size)
	87	{
	88	do_write_blocked(data, size);
	89	finish_record();
	90	}
	91
3d74982f RS	92	/*
	93	* The end of tar archives is marked by 2*512 nul bytes and after that
	94	* follows the rest of the block (if any).
	95	*/
	96	static void write_trailer(void)
	97	{
	98	int tail = BLOCKSIZE - offset;
	99	memset(block + offset, 0, tail);
	100	write_or_die(1, block, BLOCKSIZE);
	101	if (tail < 2 * RECORDSIZE) {
	102	memset(block, 0, offset);
	103	write_or_die(1, block, BLOCKSIZE);
	104	}
	105	}
	106
5544049d NTND	107	/*
	108	* queues up writes, so that all our write(2) calls write exactly one
	109	* full block; pads writes to RECORDSIZE
	110	*/
	111	static int stream_blocked(const unsigned char *sha1)
	112	{
	113	struct git_istream *st;
	114	enum object_type type;
	115	unsigned long sz;
	116	char buf[BLOCKSIZE];
	117	ssize_t readlen;
	118
	119	st = open_istream(sha1, &type, &sz, NULL);
	120	if (!st)
	121	return error("cannot stream blob %s", sha1_to_hex(sha1));
	122	for (;;) {
	123	readlen = read_istream(st, buf, sizeof(buf));
	124	if (readlen <= 0)
	125	break;
	126	do_write_blocked(buf, readlen);
	127	}
	128	close_istream(st);
	129	if (!readlen)
	130	finish_record();
	131	return readlen;
	132	}
	133
3d74982f RS	134	/*
	135	* pax extended header records have the format "%u %s=%s\n". %u contains
	136	* the size of the whole string (including the %u), the first %s is the
	137	* keyword, the second one is the value. This function constructs such a
	138	* string and appends it to a struct strbuf.
	139	*/
	140	static void strbuf_append_ext_header(struct strbuf sb, const char keyword,
	141	const char *value, unsigned int valuelen)
	142	{
7a604f16	143	int len, tmp;
3d74982f RS	144
	145	/* "%u %s=%s\n" */
	146	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
	147	for (tmp = len; tmp > 9; tmp /= 10)
	148	len++;
	149
7a604f16 PH	150	strbuf_grow(sb, len);
	151	strbuf_addf(sb, "%u %s=", len, keyword);
	152	strbuf_add(sb, value, valuelen);
	153	strbuf_addch(sb, '\n');
3d74982f RS	154	}
3d74982f RS	155
d1657b57 JK	156	/*
	157	* Like strbuf_append_ext_header, but for numeric values.
	158	*/
	159	static void strbuf_append_ext_header_uint(struct strbuf *sb,
	160	const char *keyword,
	161	uintmax_t value)
	162	{
	163	char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
	164	int len;
	165
	166	len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
	167	strbuf_append_ext_header(sb, keyword, buf, len);
	168	}
	169
3d74982f RS	170	static unsigned int ustar_header_chksum(const struct ustar_header *header)
3d74982f RS	171	{
a5a46eb9	172	const unsigned char p = (const unsigned char )header;
3d74982f	173	unsigned int chksum = 0;
a5a46eb9	174	while (p < (const unsigned char *)header->chksum)
3d74982f RS	175	chksum += *p++;
	176	chksum += sizeof(header->chksum) * ' ';
	177	p += sizeof(header->chksum);
a5a46eb9	178	while (p < (const unsigned char *)header + sizeof(struct ustar_header))
3d74982f RS	179	chksum += *p++;
	180	return chksum;
	181	}
	182
562e25ab	183	static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
3d74982f	184	{
562e25ab	185	size_t i = pathlen;
22f0dcd9 RS	186	if (i > 1 && path[i - 1] == '/')
22f0dcd9 RS	187	i--;
3d74982f RS	188	if (i > maxlen)
	189	i = maxlen;
	190	do {
	191	i--;
562e25ab	192	} while (i > 0 && path[i] != '/');
3d74982f RS	193	return i;
	194	}
	195
d240d410 NTND	196	static void prepare_header(struct archiver_args *args,
	197	struct ustar_header *header,
	198	unsigned int mode, unsigned long size)
	199	{
f2f02675 JK	200	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
	201	xsnprintf(header->size, sizeof(header->size), "%011lo", S_ISREG(mode) ? size : 0);
	202	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
d240d410	203
f2f02675 JK	204	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
f2f02675 JK	205	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
d240d410 NTND	206	strlcpy(header->uname, "root", sizeof(header->uname));
d240d410 NTND	207	strlcpy(header->gname, "root", sizeof(header->gname));
f2f02675 JK	208	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
f2f02675 JK	209	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
d240d410 NTND	210
	211	memcpy(header->magic, "ustar", 6);
	212	memcpy(header->version, "00", 2);
	213
9e6c1e91	214	xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
d240d410 NTND	215	}
d240d410 NTND	216
560b0e8f RS	217	static void write_extended_header(struct archiver_args *args,
	218	const unsigned char *sha1,
	219	const void *buffer, unsigned long size)
d240d410 NTND	220	{
	221	struct ustar_header header;
	222	unsigned int mode;
	223	memset(&header, 0, sizeof(header));
	224	*header.typeflag = TYPEFLAG_EXT_HEADER;
15c6ef7b	225	mode = 0100666;
f2f02675	226	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", sha1_to_hex(sha1));
d240d410 NTND	227	prepare_header(args, &header, mode, size);
	228	write_blocked(&header, sizeof(header));
	229	write_blocked(buffer, size);
d240d410 NTND	230	}
d240d410 NTND	231
562e25ab	232	static int write_tar_entry(struct archiver_args *args,
9cb513b7 NTND	233	const unsigned char *sha1,
	234	const char *path, size_t pathlen,
	235	unsigned int mode)
3d74982f RS	236	{
3d74982f RS	237	struct ustar_header header;
f285a2d7	238	struct strbuf ext_header = STRBUF_INIT;
9cb513b7	239	unsigned int old_mode = mode;
d1657b57	240	unsigned long size, size_in_header;
9cb513b7	241	void *buffer;
562e25ab	242	int err = 0;
3d74982f RS	243
3d74982f RS	244	memset(&header, 0, sizeof(header));
3d74982f	245
85390709 NTND	246	if (S_ISDIR(mode) \|\| S_ISGITLINK(mode)) {
	247	*header.typeflag = TYPEFLAG_DIR;
	248	mode = (mode \| 0777) & ~tar_umask;
	249	} else if (S_ISLNK(mode)) {
	250	*header.typeflag = TYPEFLAG_LNK;
	251	mode \|= 0777;
	252	} else if (S_ISREG(mode)) {
	253	*header.typeflag = TYPEFLAG_REG;
	254	mode = (mode \| ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
3d74982f	255	} else {
85390709 NTND	256	return error("unsupported file mode: 0%o (SHA1: %s)",
	257	mode, sha1_to_hex(sha1));
	258	}
	259	if (pathlen > sizeof(header.name)) {
	260	size_t plen = get_path_prefix(path, pathlen,
	261	sizeof(header.prefix));
	262	size_t rest = pathlen - plen - 1;
	263	if (plen > 0 && rest <= sizeof(header.name)) {
	264	memcpy(header.prefix, path, plen);
108332c7	265	memcpy(header.name, path + plen + 1, rest);
3d74982f	266	} else {
f2f02675 JK	267	xsnprintf(header.name, sizeof(header.name), "%s.data",
f2f02675 JK	268	sha1_to_hex(sha1));
85390709 NTND	269	strbuf_append_ext_header(&ext_header, "path",
85390709 NTND	270	path, pathlen);
3d74982f	271	}
85390709 NTND	272	} else
85390709 NTND	273	memcpy(header.name, path, pathlen);
3d74982f	274
5544049d NTND	275	if (S_ISREG(mode) && !args->convert &&
	276	sha1_object_info(sha1, &size) == OBJ_BLOB &&
	277	size > big_file_threshold)
	278	buffer = NULL;
	279	else if (S_ISLNK(mode) \|\| S_ISREG(mode)) {
9cb513b7 NTND	280	enum object_type type;
	281	buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
	282	if (!buffer)
	283	return error("cannot read %s", sha1_to_hex(sha1));
	284	} else {
	285	buffer = NULL;
	286	size = 0;
	287	}
	288
	289	if (S_ISLNK(mode)) {
3d74982f	290	if (size > sizeof(header.linkname)) {
f2f02675 JK	291	xsnprintf(header.linkname, sizeof(header.linkname),
f2f02675 JK	292	"see %s.paxheader", sha1_to_hex(sha1));
3d74982f RS	293	strbuf_append_ext_header(&ext_header, "linkpath",
	294	buffer, size);
	295	} else
	296	memcpy(header.linkname, buffer, size);
	297	}
	298
d1657b57 JK	299	size_in_header = size;
	300	if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
	301	size_in_header = 0;
	302	strbuf_append_ext_header_uint(&ext_header, "size", size);
	303	}
	304
	305	prepare_header(args, &header, mode, size_in_header);
3d74982f RS	306
3d74982f RS	307	if (ext_header.len > 0) {
560b0e8f RS	308	write_extended_header(args, sha1, ext_header.buf,
560b0e8f RS	309	ext_header.len);
3d74982f	310	}
7a604f16	311	strbuf_release(&ext_header);
3d74982f	312	write_blocked(&header, sizeof(header));
5544049d NTND	313	if (S_ISREG(mode) && size > 0) {
	314	if (buffer)
	315	write_blocked(buffer, size);
	316	else
	317	err = stream_blocked(sha1);
	318	}
9cb513b7	319	free(buffer);
562e25ab	320	return err;
3d74982f RS	321	}
3d74982f RS	322
5caeeb83	323	static void write_global_extended_header(struct archiver_args *args)
3d74982f	324	{
562e25ab	325	const unsigned char *sha1 = args->commit_sha1;
f285a2d7	326	struct strbuf ext_header = STRBUF_INIT;
d240d410 NTND	327	struct ustar_header header;
d240d410 NTND	328	unsigned int mode;
7a604f16	329
6e8e0991 JK	330	if (sha1)
	331	strbuf_append_ext_header(&ext_header, "comment",
	332	sha1_to_hex(sha1), 40);
	333	if (args->time > USTAR_MAX_MTIME) {
	334	strbuf_append_ext_header_uint(&ext_header, "mtime",
	335	args->time);
	336	args->time = USTAR_MAX_MTIME;
	337	}
	338
	339	if (!ext_header.len)
5caeeb83	340	return;
6e8e0991	341
d240d410 NTND	342	memset(&header, 0, sizeof(header));
d240d410 NTND	343	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
15c6ef7b	344	mode = 0100666;
5096d490	345	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
d240d410 NTND	346	prepare_header(args, &header, mode, ext_header.len);
	347	write_blocked(&header, sizeof(header));
	348	write_blocked(ext_header.buf, ext_header.len);
7a604f16	349	strbuf_release(&ext_header);
3d74982f RS	350	}
3d74982f RS	351
767cf457 JK	352	static struct archiver **tar_filters;
	353	static int nr_tar_filters;
	354	static int alloc_tar_filters;
	355
	356	static struct archiver find_tar_filter(const char name, int len)
	357	{
	358	int i;
	359	for (i = 0; i < nr_tar_filters; i++) {
	360	struct archiver *ar = tar_filters[i];
	361	if (!strncmp(ar->name, name, len) && !ar->name[len])
	362	return ar;
	363	}
	364	return NULL;
	365	}
	366
	367	static int tar_filter_config(const char var, const char value, void *data)
	368	{
	369	struct archiver *ar;
767cf457 JK	370	const char *name;
	371	const char *type;
	372	int namelen;
	373
785a0429	374	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 \|\| !name)
767cf457	375	return 0;
767cf457 JK	376
	377	ar = find_tar_filter(name, namelen);
	378	if (!ar) {
	379	ar = xcalloc(1, sizeof(*ar));
	380	ar->name = xmemdupz(name, namelen);
	381	ar->write_archive = write_tar_filter_archive;
	382	ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
	383	ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
	384	tar_filters[nr_tar_filters++] = ar;
	385	}
	386
	387	if (!strcmp(type, "command")) {
	388	if (!value)
	389	return config_error_nonbool(var);
	390	free(ar->data);
	391	ar->data = xstrdup(value);
	392	return 0;
	393	}
7b97730b JK	394	if (!strcmp(type, "remote")) {
	395	if (git_config_bool(var, value))
	396	ar->flags \|= ARCHIVER_REMOTE;
	397	else
	398	ar->flags &= ~ARCHIVER_REMOTE;
	399	return 0;
	400	}
767cf457 JK	401
	402	return 0;
	403	}
	404
ef90d6d4	405	static int git_tar_config(const char var, const char value, void *cb)
3d74982f RS	406	{
3d74982f RS	407	if (!strcmp(var, "tar.umask")) {
cc1816b0	408	if (value && !strcmp(value, "user")) {
3d74982f RS	409	tar_umask = umask(0);
	410	umask(tar_umask);
	411	} else {
	412	tar_umask = git_config_int(var, value);
	413	}
	414	return 0;
	415	}
767cf457 JK	416
767cf457 JK	417	return tar_filter_config(var, value, cb);
3d74982f RS	418	}
3d74982f RS	419
4d7c9898 JK	420	static int write_tar_archive(const struct archiver *ar,
4d7c9898 JK	421	struct archiver_args *args)
3d74982f	422	{
562e25ab	423	int err = 0;
3d74982f	424
5caeeb83 JK	425	write_global_extended_header(args);
5caeeb83 JK	426	err = write_archive_entries(args, write_tar_entry);
562e25ab RS	427	if (!err)
	428	write_trailer();
	429	return err;
3d74982f	430	}
13e0f88d	431
767cf457 JK	432	static int write_tar_filter_archive(const struct archiver *ar,
	433	struct archiver_args *args)
	434	{
	435	struct strbuf cmd = STRBUF_INIT;
d3180279	436	struct child_process filter = CHILD_PROCESS_INIT;
767cf457 JK	437	const char *argv[2];
	438	int r;
	439
	440	if (!ar->data)
	441	die("BUG: tar-filter archiver called with no filter defined");
	442
	443	strbuf_addstr(&cmd, ar->data);
	444	if (args->compression_level >= 0)
	445	strbuf_addf(&cmd, " -%d", args->compression_level);
	446
767cf457 JK	447	argv[0] = cmd.buf;
	448	argv[1] = NULL;
	449	filter.argv = argv;
	450	filter.use_shell = 1;
	451	filter.in = -1;
	452
	453	if (start_command(&filter) < 0)
	454	die_errno("unable to start '%s' filter", argv[0]);
	455	close(1);
	456	if (dup2(filter.in, 1) < 0)
	457	die_errno("unable to redirect descriptor");
	458	close(filter.in);
	459
	460	r = write_tar_archive(ar, args);
	461
	462	close(1);
	463	if (finish_command(&filter) != 0)
	464	die("'%s' filter reported error", argv[0]);
	465
	466	strbuf_release(&cmd);
	467	return r;
	468	}
	469
13e0f88d JK	470	static struct archiver tar_archiver = {
	471	"tar",
	472	write_tar_archive,
7b97730b	473	ARCHIVER_REMOTE
13e0f88d JK	474	};
	475
	476	void init_tar_archiver(void)
	477	{
767cf457	478	int i;
13e0f88d	479	register_archiver(&tar_archiver);
767cf457	480
0e804e09	481	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
7b97730b	482	tar_filter_config("tar.tgz.remote", "true", NULL);
0e804e09	483	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
7b97730b	484	tar_filter_config("tar.tar.gz.remote", "true", NULL);
13e0f88d	485	git_config(git_tar_config, NULL);
767cf457 JK	486	for (i = 0; i < nr_tar_filters; i++) {
	487	/* omit any filters that never had a command configured */
	488	if (tar_filters[i]->data)
	489	register_archiver(tar_filters[i]);
	490	}
13e0f88d	491	}