[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 "object-store.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
#else
#define USTAR_MAX_SIZE 077777777777UL
#endif
#if TIME_MAX == 0xFFFFFFFF
#define USTAR_MAX_MTIME TIME_MAX
#else
#define USTAR_MAX_MTIME 077777777777ULL
#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 struct object_id *oid)
{
	struct git_istream *st;
	enum object_type type;
	unsigned long sz;
	char buf[BLOCKSIZE];
	ssize_t readlen;

	st = open_istream(oid, &type, &sz, NULL);
	if (!st)
		return error("cannot stream blob %s", oid_to_hex(oid));
	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 struct object_id *oid,
				  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", oid_to_hex(oid));
	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 struct object_id *oid,
			   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, oid_to_hex(oid));
	}
	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",
				  oid_to_hex(oid));
			strbuf_append_ext_header(&ext_header, "path",
						 path, pathlen);
		}
	} else
		memcpy(header.name, path, pathlen);

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

	if (S_ISLNK(mode)) {
		if (size > sizeof(header.linkname)) {
			xsnprintf(header.linkname, sizeof(header.linkname),
				  "see %s.paxheader", oid_to_hex(oid));
			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, oid, 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(oid);
	}
	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)
		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"
cbd53a21	8	#include "object-store.h"
5544049d	9	#include "streaming.h"
767cf457	10	#include "run-command.h"
3d74982f RS	11
	12	#define RECORDSIZE (512)
	13	#define BLOCKSIZE (RECORDSIZE * 20)
	14
	15	static char block[BLOCKSIZE];
	16	static unsigned long offset;
	17
f08b3b0e	18	static int tar_umask = 002;
3d74982f	19
767cf457 JK	20	static int write_tar_filter_archive(const struct archiver *ar,
	21	struct archiver_args *args);
	22
d1657b57 JK	23	/*
	24	* This is the max value that a ustar size header can specify, as it is fixed
	25	* at 11 octal digits. POSIX specifies that we switch to extended headers at
	26	* this size.
6e8e0991 JK	27	*
6e8e0991 JK	28	* Likewise for the mtime (which happens to use a buffer of the same size).
d1657b57	29	*/
29493589 JH	30	#if ULONG_MAX == 0xFFFFFFFF
29493589 JH	31	#define USTAR_MAX_SIZE ULONG_MAX
29493589	32	#else
3f789719	33	#define USTAR_MAX_SIZE 077777777777UL
dddbad72 JS	34	#endif
	35	#if TIME_MAX == 0xFFFFFFFF
	36	#define USTAR_MAX_MTIME TIME_MAX
	37	#else
3f789719	38	#define USTAR_MAX_MTIME 077777777777ULL
29493589	39	#endif
d1657b57	40
3d74982f RS	41	/* writes out the whole block, but only if it is full */
	42	static void write_if_needed(void)
	43	{
	44	if (offset == BLOCKSIZE) {
	45	write_or_die(1, block, BLOCKSIZE);
	46	offset = 0;
	47	}
	48	}
	49
	50	/*
	51	* queues up writes, so that all our write(2) calls write exactly one
	52	* full block; pads writes to RECORDSIZE
	53	*/
5544049d	54	static void do_write_blocked(const void *data, unsigned long size)
3d74982f RS	55	{
3d74982f RS	56	const char *buf = data;
3d74982f RS	57
	58	if (offset) {
	59	unsigned long chunk = BLOCKSIZE - offset;
	60	if (size < chunk)
	61	chunk = size;
	62	memcpy(block + offset, buf, chunk);
	63	size -= chunk;
	64	offset += chunk;
	65	buf += chunk;
	66	write_if_needed();
	67	}
	68	while (size >= BLOCKSIZE) {
	69	write_or_die(1, buf, BLOCKSIZE);
	70	size -= BLOCKSIZE;
	71	buf += BLOCKSIZE;
	72	}
	73	if (size) {
	74	memcpy(block + offset, buf, size);
	75	offset += size;
	76	}
5544049d NTND	77	}
	78
	79	static void finish_record(void)
	80	{
	81	unsigned long tail;
3d74982f RS	82	tail = offset % RECORDSIZE;
	83	if (tail) {
	84	memset(block + offset, 0, RECORDSIZE - tail);
	85	offset += RECORDSIZE - tail;
	86	}
	87	write_if_needed();
	88	}
	89
5544049d NTND	90	static void write_blocked(const void *data, unsigned long size)
	91	{
	92	do_write_blocked(data, size);
	93	finish_record();
	94	}
	95
3d74982f RS	96	/*
	97	* The end of tar archives is marked by 2*512 nul bytes and after that
	98	* follows the rest of the block (if any).
	99	*/
	100	static void write_trailer(void)
	101	{
	102	int tail = BLOCKSIZE - offset;
	103	memset(block + offset, 0, tail);
	104	write_or_die(1, block, BLOCKSIZE);
	105	if (tail < 2 * RECORDSIZE) {
	106	memset(block, 0, offset);
	107	write_or_die(1, block, BLOCKSIZE);
	108	}
	109	}
	110
5544049d NTND	111	/*
	112	* queues up writes, so that all our write(2) calls write exactly one
	113	* full block; pads writes to RECORDSIZE
	114	*/
015ff4f8	115	static int stream_blocked(const struct object_id *oid)
5544049d NTND	116	{
	117	struct git_istream *st;
	118	enum object_type type;
	119	unsigned long sz;
	120	char buf[BLOCKSIZE];
	121	ssize_t readlen;
	122
ef7b5195	123	st = open_istream(oid, &type, &sz, NULL);
5544049d	124	if (!st)
015ff4f8	125	return error("cannot stream blob %s", oid_to_hex(oid));
5544049d NTND	126	for (;;) {
	127	readlen = read_istream(st, buf, sizeof(buf));
	128	if (readlen <= 0)
	129	break;
	130	do_write_blocked(buf, readlen);
	131	}
	132	close_istream(st);
	133	if (!readlen)
	134	finish_record();
	135	return readlen;
	136	}
	137
3d74982f RS	138	/*
	139	* pax extended header records have the format "%u %s=%s\n". %u contains
	140	* the size of the whole string (including the %u), the first %s is the
	141	* keyword, the second one is the value. This function constructs such a
	142	* string and appends it to a struct strbuf.
	143	*/
	144	static void strbuf_append_ext_header(struct strbuf sb, const char keyword,
	145	const char *value, unsigned int valuelen)
	146	{
7a604f16	147	int len, tmp;
3d74982f RS	148
	149	/* "%u %s=%s\n" */
	150	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
	151	for (tmp = len; tmp > 9; tmp /= 10)
	152	len++;
	153
7a604f16 PH	154	strbuf_grow(sb, len);
	155	strbuf_addf(sb, "%u %s=", len, keyword);
	156	strbuf_add(sb, value, valuelen);
	157	strbuf_addch(sb, '\n');
3d74982f RS	158	}
3d74982f RS	159
d1657b57 JK	160	/*
	161	* Like strbuf_append_ext_header, but for numeric values.
	162	*/
	163	static void strbuf_append_ext_header_uint(struct strbuf *sb,
	164	const char *keyword,
	165	uintmax_t value)
	166	{
	167	char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
	168	int len;
	169
	170	len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
	171	strbuf_append_ext_header(sb, keyword, buf, len);
	172	}
	173
3d74982f RS	174	static unsigned int ustar_header_chksum(const struct ustar_header *header)
3d74982f RS	175	{
a5a46eb9	176	const unsigned char p = (const unsigned char )header;
3d74982f	177	unsigned int chksum = 0;
a5a46eb9	178	while (p < (const unsigned char *)header->chksum)
3d74982f RS	179	chksum += *p++;
	180	chksum += sizeof(header->chksum) * ' ';
	181	p += sizeof(header->chksum);
a5a46eb9	182	while (p < (const unsigned char *)header + sizeof(struct ustar_header))
3d74982f RS	183	chksum += *p++;
	184	return chksum;
	185	}
	186
562e25ab	187	static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
3d74982f	188	{
562e25ab	189	size_t i = pathlen;
22f0dcd9 RS	190	if (i > 1 && path[i - 1] == '/')
22f0dcd9 RS	191	i--;
3d74982f RS	192	if (i > maxlen)
	193	i = maxlen;
	194	do {
	195	i--;
562e25ab	196	} while (i > 0 && path[i] != '/');
3d74982f RS	197	return i;
	198	}
	199
d240d410 NTND	200	static void prepare_header(struct archiver_args *args,
	201	struct ustar_header *header,
	202	unsigned int mode, unsigned long size)
	203	{
f2f02675 JK	204	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
	205	xsnprintf(header->size, sizeof(header->size), "%011lo", S_ISREG(mode) ? size : 0);
	206	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
d240d410	207
f2f02675 JK	208	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
f2f02675 JK	209	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
d240d410 NTND	210	strlcpy(header->uname, "root", sizeof(header->uname));
d240d410 NTND	211	strlcpy(header->gname, "root", sizeof(header->gname));
f2f02675 JK	212	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
f2f02675 JK	213	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
d240d410 NTND	214
	215	memcpy(header->magic, "ustar", 6);
	216	memcpy(header->version, "00", 2);
	217
9e6c1e91	218	xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
d240d410 NTND	219	}
d240d410 NTND	220
560b0e8f	221	static void write_extended_header(struct archiver_args *args,
015ff4f8	222	const struct object_id *oid,
560b0e8f	223	const void *buffer, unsigned long size)
d240d410 NTND	224	{
	225	struct ustar_header header;
	226	unsigned int mode;
	227	memset(&header, 0, sizeof(header));
	228	*header.typeflag = TYPEFLAG_EXT_HEADER;
15c6ef7b	229	mode = 0100666;
015ff4f8	230	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
d240d410 NTND	231	prepare_header(args, &header, mode, size);
	232	write_blocked(&header, sizeof(header));
	233	write_blocked(buffer, size);
d240d410 NTND	234	}
d240d410 NTND	235
562e25ab	236	static int write_tar_entry(struct archiver_args *args,
015ff4f8	237	const struct object_id *oid,
9cb513b7 NTND	238	const char *path, size_t pathlen,
9cb513b7 NTND	239	unsigned int mode)
3d74982f RS	240	{
3d74982f RS	241	struct ustar_header header;
f285a2d7	242	struct strbuf ext_header = STRBUF_INIT;
9cb513b7	243	unsigned int old_mode = mode;
d1657b57	244	unsigned long size, size_in_header;
9cb513b7	245	void *buffer;
562e25ab	246	int err = 0;
3d74982f RS	247
3d74982f RS	248	memset(&header, 0, sizeof(header));
3d74982f	249
85390709 NTND	250	if (S_ISDIR(mode) \|\| S_ISGITLINK(mode)) {
	251	*header.typeflag = TYPEFLAG_DIR;
	252	mode = (mode \| 0777) & ~tar_umask;
	253	} else if (S_ISLNK(mode)) {
	254	*header.typeflag = TYPEFLAG_LNK;
	255	mode \|= 0777;
	256	} else if (S_ISREG(mode)) {
	257	*header.typeflag = TYPEFLAG_REG;
	258	mode = (mode \| ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
3d74982f	259	} else {
85390709	260	return error("unsupported file mode: 0%o (SHA1: %s)",
015ff4f8	261	mode, oid_to_hex(oid));
85390709 NTND	262	}
	263	if (pathlen > sizeof(header.name)) {
	264	size_t plen = get_path_prefix(path, pathlen,
	265	sizeof(header.prefix));
	266	size_t rest = pathlen - plen - 1;
	267	if (plen > 0 && rest <= sizeof(header.name)) {
	268	memcpy(header.prefix, path, plen);
108332c7	269	memcpy(header.name, path + plen + 1, rest);
3d74982f	270	} else {
f2f02675	271	xsnprintf(header.name, sizeof(header.name), "%s.data",
015ff4f8	272	oid_to_hex(oid));
85390709 NTND	273	strbuf_append_ext_header(&ext_header, "path",
85390709 NTND	274	path, pathlen);
3d74982f	275	}
85390709 NTND	276	} else
85390709 NTND	277	memcpy(header.name, path, pathlen);
3d74982f	278
5544049d	279	if (S_ISREG(mode) && !args->convert &&
0df8e965	280	oid_object_info(the_repository, oid, &size) == OBJ_BLOB &&
5544049d NTND	281	size > big_file_threshold)
	282	buffer = NULL;
	283	else if (S_ISLNK(mode) \|\| S_ISREG(mode)) {
9cb513b7	284	enum object_type type;
e5ec981a	285	buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size);
9cb513b7	286	if (!buffer)
015ff4f8	287	return error("cannot read %s", oid_to_hex(oid));
9cb513b7 NTND	288	} else {
	289	buffer = NULL;
	290	size = 0;
	291	}
	292
	293	if (S_ISLNK(mode)) {
3d74982f	294	if (size > sizeof(header.linkname)) {
f2f02675	295	xsnprintf(header.linkname, sizeof(header.linkname),
015ff4f8	296	"see %s.paxheader", oid_to_hex(oid));
3d74982f RS	297	strbuf_append_ext_header(&ext_header, "linkpath",
	298	buffer, size);
	299	} else
	300	memcpy(header.linkname, buffer, size);
	301	}
	302
d1657b57 JK	303	size_in_header = size;
	304	if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
	305	size_in_header = 0;
	306	strbuf_append_ext_header_uint(&ext_header, "size", size);
	307	}
	308
	309	prepare_header(args, &header, mode, size_in_header);
3d74982f RS	310
3d74982f RS	311	if (ext_header.len > 0) {
015ff4f8	312	write_extended_header(args, oid, ext_header.buf,
560b0e8f	313	ext_header.len);
3d74982f	314	}
7a604f16	315	strbuf_release(&ext_header);
3d74982f	316	write_blocked(&header, sizeof(header));
5544049d NTND	317	if (S_ISREG(mode) && size > 0) {
	318	if (buffer)
	319	write_blocked(buffer, size);
	320	else
015ff4f8	321	err = stream_blocked(oid);
5544049d	322	}
9cb513b7	323	free(buffer);
562e25ab	324	return err;
3d74982f RS	325	}
3d74982f RS	326
5caeeb83	327	static void write_global_extended_header(struct archiver_args *args)
3d74982f	328	{
562e25ab	329	const unsigned char *sha1 = args->commit_sha1;
f285a2d7	330	struct strbuf ext_header = STRBUF_INIT;
d240d410 NTND	331	struct ustar_header header;
d240d410 NTND	332	unsigned int mode;
7a604f16	333
6e8e0991 JK	334	if (sha1)
	335	strbuf_append_ext_header(&ext_header, "comment",
	336	sha1_to_hex(sha1), 40);
	337	if (args->time > USTAR_MAX_MTIME) {
	338	strbuf_append_ext_header_uint(&ext_header, "mtime",
	339	args->time);
	340	args->time = USTAR_MAX_MTIME;
	341	}
	342
	343	if (!ext_header.len)
5caeeb83	344	return;
6e8e0991	345
d240d410 NTND	346	memset(&header, 0, sizeof(header));
d240d410 NTND	347	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
15c6ef7b	348	mode = 0100666;
5096d490	349	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
d240d410 NTND	350	prepare_header(args, &header, mode, ext_header.len);
	351	write_blocked(&header, sizeof(header));
	352	write_blocked(ext_header.buf, ext_header.len);
7a604f16	353	strbuf_release(&ext_header);
3d74982f RS	354	}
3d74982f RS	355
767cf457 JK	356	static struct archiver **tar_filters;
	357	static int nr_tar_filters;
	358	static int alloc_tar_filters;
	359
	360	static struct archiver find_tar_filter(const char name, int len)
	361	{
	362	int i;
	363	for (i = 0; i < nr_tar_filters; i++) {
	364	struct archiver *ar = tar_filters[i];
	365	if (!strncmp(ar->name, name, len) && !ar->name[len])
	366	return ar;
	367	}
	368	return NULL;
	369	}
	370
	371	static int tar_filter_config(const char var, const char value, void *data)
	372	{
	373	struct archiver *ar;
767cf457 JK	374	const char *name;
	375	const char *type;
	376	int namelen;
	377
785a0429	378	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 \|\| !name)
767cf457	379	return 0;
767cf457 JK	380
	381	ar = find_tar_filter(name, namelen);
	382	if (!ar) {
	383	ar = xcalloc(1, sizeof(*ar));
	384	ar->name = xmemdupz(name, namelen);
	385	ar->write_archive = write_tar_filter_archive;
	386	ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
	387	ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
	388	tar_filters[nr_tar_filters++] = ar;
	389	}
	390
	391	if (!strcmp(type, "command")) {
	392	if (!value)
	393	return config_error_nonbool(var);
	394	free(ar->data);
	395	ar->data = xstrdup(value);
	396	return 0;
	397	}
7b97730b JK	398	if (!strcmp(type, "remote")) {
	399	if (git_config_bool(var, value))
	400	ar->flags \|= ARCHIVER_REMOTE;
	401	else
	402	ar->flags &= ~ARCHIVER_REMOTE;
	403	return 0;
	404	}
767cf457 JK	405
	406	return 0;
	407	}
	408
ef90d6d4	409	static int git_tar_config(const char var, const char value, void *cb)
3d74982f RS	410	{
3d74982f RS	411	if (!strcmp(var, "tar.umask")) {
cc1816b0	412	if (value && !strcmp(value, "user")) {
3d74982f RS	413	tar_umask = umask(0);
	414	umask(tar_umask);
	415	} else {
	416	tar_umask = git_config_int(var, value);
	417	}
	418	return 0;
	419	}
767cf457 JK	420
767cf457 JK	421	return tar_filter_config(var, value, cb);
3d74982f RS	422	}
3d74982f RS	423
4d7c9898 JK	424	static int write_tar_archive(const struct archiver *ar,
4d7c9898 JK	425	struct archiver_args *args)
3d74982f	426	{
562e25ab	427	int err = 0;
3d74982f	428
5caeeb83 JK	429	write_global_extended_header(args);
5caeeb83 JK	430	err = write_archive_entries(args, write_tar_entry);
562e25ab RS	431	if (!err)
	432	write_trailer();
	433	return err;
3d74982f	434	}
13e0f88d	435
767cf457 JK	436	static int write_tar_filter_archive(const struct archiver *ar,
	437	struct archiver_args *args)
	438	{
	439	struct strbuf cmd = STRBUF_INIT;
d3180279	440	struct child_process filter = CHILD_PROCESS_INIT;
767cf457 JK	441	const char *argv[2];
	442	int r;
	443
	444	if (!ar->data)
033abf97	445	BUG("tar-filter archiver called with no filter defined");
767cf457 JK	446
	447	strbuf_addstr(&cmd, ar->data);
	448	if (args->compression_level >= 0)
	449	strbuf_addf(&cmd, " -%d", args->compression_level);
	450
767cf457 JK	451	argv[0] = cmd.buf;
	452	argv[1] = NULL;
	453	filter.argv = argv;
	454	filter.use_shell = 1;
	455	filter.in = -1;
	456
	457	if (start_command(&filter) < 0)
	458	die_errno("unable to start '%s' filter", argv[0]);
	459	close(1);
	460	if (dup2(filter.in, 1) < 0)
	461	die_errno("unable to redirect descriptor");
	462	close(filter.in);
	463
	464	r = write_tar_archive(ar, args);
	465
	466	close(1);
	467	if (finish_command(&filter) != 0)
	468	die("'%s' filter reported error", argv[0]);
	469
	470	strbuf_release(&cmd);
	471	return r;
	472	}
	473
13e0f88d JK	474	static struct archiver tar_archiver = {
	475	"tar",
	476	write_tar_archive,
7b97730b	477	ARCHIVER_REMOTE
13e0f88d JK	478	};
	479
	480	void init_tar_archiver(void)
	481	{
767cf457	482	int i;
13e0f88d	483	register_archiver(&tar_archiver);
767cf457	484
0e804e09	485	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
7b97730b	486	tar_filter_config("tar.tgz.remote", "true", NULL);
0e804e09	487	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
7b97730b	488	tar_filter_config("tar.tar.gz.remote", "true", NULL);
13e0f88d	489	git_config(git_tar_config, NULL);
767cf457 JK	490	for (i = 0; i < nr_tar_filters; i++) {
	491	/* omit any filters that never had a command configured */
	492	if (tar_filters[i]->data)
	493	register_archiver(tar_filters[i]);
	494	}
13e0f88d	495	}