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

/*
 * Copyright (c) 2005 Rene Scharfe
 */
#include <time.h>
#include "cache.h"

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

#define TYPEFLAG_AUTO		'\0'
#define TYPEFLAG_REG		'0'
#define TYPEFLAG_LNK		'2'
#define TYPEFLAG_DIR		'5'
#define TYPEFLAG_GLOBAL_HEADER	'g'
#define TYPEFLAG_EXT_HEADER	'x'

#define EXT_HEADER_PATH		1
#define EXT_HEADER_LINKPATH	2

static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";

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

static const char *basedir;
static time_t archive_time;

struct path_prefix {
	struct path_prefix *prev;
	const char *name;
};

/* tries hard to write, either succeeds or dies in the attempt */
static void reliable_write(void *buf, unsigned long size)
{
	while (size > 0) {
		long ret = write(1, buf, size);
		if (ret < 0) {
			if (errno == EAGAIN)
				continue;
			if (errno == EPIPE)
				exit(0);
			die("git-tar-tree: %s", strerror(errno));
		} else if (!ret) {
			die("git-tar-tree: disk full?");
		}
		size -= ret;
		buf += ret;
	}
}

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

/* acquire the next record from the buffer; user must call write_if_needed() */
static char *get_record(void)
{
	char *p = block + offset;
	memset(p, 0, RECORDSIZE);
	offset += RECORDSIZE;
	return p;
}

/*
 * The end of tar archives is marked by 1024 nul bytes and after that
 * follows the rest of the block (if any).
 */
static void write_trailer(void)
{
	get_record();
	write_if_needed();
	get_record();
	write_if_needed();
	while (offset) {
		get_record();
		write_if_needed();
	}
}

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

	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) {
		reliable_write(buf, BLOCKSIZE);
		size -= BLOCKSIZE;
		buf += BLOCKSIZE;
	}
	if (size) {
		memcpy(block + offset, buf, size);
		buf += size;
		offset += size;
	}
	tail = offset % RECORDSIZE;
	if (tail)  {
		memset(block + offset, 0, RECORDSIZE - tail);
		offset += RECORDSIZE - tail;
	}
	write_if_needed();
}

static void append_string(char **p, const char *s)
{
	unsigned int len = strlen(s);
	memcpy(*p, s, len);
	*p += len;
}

static void append_char(char **p, char c)
{
	**p = c;
	*p += 1;
}

static void append_path_prefix(char **buffer, struct path_prefix *prefix)
{
	if (!prefix)
		return;
	append_path_prefix(buffer, prefix->prev);
	append_string(buffer, prefix->name);
	append_char(buffer, '/');
}

static unsigned int path_prefix_len(struct path_prefix *prefix)
{
	if (!prefix)
		return 0;
	return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
}

static void append_path(char **p, int is_dir, const char *basepath,
                        struct path_prefix *prefix, const char *path)
{
	if (basepath) {
		append_string(p, basepath);
		append_char(p, '/');
	}
	append_path_prefix(p, prefix);
	append_string(p, path);
	if (is_dir)
		append_char(p, '/');
}

static unsigned int path_len(int is_dir, const char *basepath,
                             struct path_prefix *prefix, const char *path)
{
	unsigned int len = 0;
	if (basepath)
		len += strlen(basepath) + 1;
	len += path_prefix_len(prefix) + strlen(path);
	if (is_dir)
		len++;
	return len;
}

static void append_extended_header_prefix(char **p, unsigned int size,
                                          const char *keyword)
{
	int len = sprintf(*p, "%u %s=", size, keyword);
	*p += len;
}

static unsigned int extended_header_len(const char *keyword,
                                        unsigned int valuelen)
{
	/* "%u %s=%s\n" */
	unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
	if (len > 9)
		len++;
	if (len > 99)
		len++;
	return len;
}

static void append_extended_header(char **p, const char *keyword,
                                   const char *value, unsigned int len)
{
	unsigned int size = extended_header_len(keyword, len);
	append_extended_header_prefix(p, size, keyword);
	memcpy(*p, value, len);
	*p += len;
	append_char(p, '\n');
}

static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
                         const char *, unsigned int, void *, unsigned long);

/* stores a pax extended header directly in the block buffer */
static void write_extended_header(const char *headerfilename, int is_dir,
                                  unsigned int flags, const char *basepath,
                                  struct path_prefix *prefix,
                                  const char *path, unsigned int namelen,
                                  void *content, unsigned int contentsize)
{
	char *buffer, *p;
	unsigned int pathlen, size, linkpathlen = 0;

	size = pathlen = extended_header_len("path", namelen);
	if (flags & EXT_HEADER_LINKPATH) {
		linkpathlen = extended_header_len("linkpath", contentsize);
		size += linkpathlen;
	}
	write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
	             0100600, NULL, size);

	buffer = p = malloc(size);
	if (!buffer)
		die("git-tar-tree: %s", strerror(errno));
	append_extended_header_prefix(&p, pathlen, "path");
	append_path(&p, is_dir, basepath, prefix, path);
	append_char(&p, '\n');
	if (flags & EXT_HEADER_LINKPATH)
		append_extended_header(&p, "linkpath", content, contentsize);
	write_blocked(buffer, size);
	free(buffer);
}

static void write_global_extended_header(const unsigned char *sha1)
{
	char *p;
	unsigned int size;

	size = extended_header_len("comment", 40);
	write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
	             "pax_global_header", 0100600, NULL, size);

	p = get_record();
	append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
	write_if_needed();
}

/* stores a ustar header directly in the block buffer */
static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
                         struct path_prefix *prefix, const char *path,
                         unsigned int mode, void *buffer, unsigned long size)
{
	unsigned int namelen; 
	char *header = NULL;
	unsigned int checksum = 0;
	int i;
	unsigned int ext_header = 0;

	if (typeflag == TYPEFLAG_AUTO) {
		if (S_ISDIR(mode))
			typeflag = TYPEFLAG_DIR;
		else if (S_ISLNK(mode))
			typeflag = TYPEFLAG_LNK;
		else
			typeflag = TYPEFLAG_REG;
	}

	namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
	if (namelen > 100)
		ext_header |= EXT_HEADER_PATH;
	if (typeflag == TYPEFLAG_LNK && size > 100)
		ext_header |= EXT_HEADER_LINKPATH;

	/* the extended header must be written before the normal one */
	if (ext_header) {
		char headerfilename[51];
		sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
		write_extended_header(headerfilename, S_ISDIR(mode),
		                      ext_header, basepath, prefix, path,
		                      namelen, buffer, size);
	}

	header = get_record();

	if (ext_header) {
		sprintf(header, "%s.data", sha1_to_hex(sha1));
	} else {
		char *p = header;
		append_path(&p, S_ISDIR(mode), basepath, prefix, path);
	}

	if (typeflag == TYPEFLAG_LNK) {
		if (ext_header & EXT_HEADER_LINKPATH) {
			sprintf(&header[157], "see %s.paxheader",
			        sha1_to_hex(sha1));
		} else {
			if (buffer)
				strncpy(&header[157], buffer, size);
		}
	}

	if (S_ISDIR(mode))
		mode |= 0755;	/* GIT doesn't store permissions of dirs */
	if (S_ISLNK(mode))
		mode |= 0777;   /* ... nor of symlinks */
	sprintf(&header[100], "%07o", mode & 07777);

	/* XXX: should we provide more meaningful info here? */
	sprintf(&header[108], "%07o", 0);	/* uid */
	sprintf(&header[116], "%07o", 0);	/* gid */
	strncpy(&header[265], "git", 31);	/* uname */
	strncpy(&header[297], "git", 31);	/* gname */

	if (S_ISDIR(mode) || S_ISLNK(mode))
		size = 0;
	sprintf(&header[124], "%011lo", size);
	sprintf(&header[136], "%011lo", archive_time);

	header[156] = typeflag;

	memcpy(&header[257], "ustar", 6);
	memcpy(&header[263], "00", 2);

	printf(&header[329], "%07o", 0);	/* devmajor */
	printf(&header[337], "%07o", 0);	/* devminor */

	memset(&header[148], ' ', 8);
	for (i = 0; i < RECORDSIZE; i++)
		checksum += header[i];
	sprintf(&header[148], "%07o", checksum & 0x1fffff);

	write_if_needed();
}

static void traverse_tree(void *buffer, unsigned long size,
			  struct path_prefix *prefix)
{
	struct path_prefix this_prefix;
	this_prefix.prev = prefix;

	while (size) {
		int namelen = strlen(buffer)+1;
		void *eltbuf;
		char elttype[20];
		unsigned long eltsize;
		unsigned char *sha1 = buffer + namelen;
		char *path = strchr(buffer, ' ') + 1;
		unsigned int mode;

		if (size < namelen + 20 || sscanf(buffer, "%o", &mode) != 1)
			die("corrupt 'tree' file");
		buffer = sha1 + 20;
		size -= namelen + 20;

		eltbuf = read_sha1_file(sha1, elttype, &eltsize);
		if (!eltbuf)
			die("cannot read %s", sha1_to_hex(sha1));
		write_header(sha1, TYPEFLAG_AUTO, basedir, prefix, path,
		             mode, eltbuf, eltsize);
		if (!strcmp(elttype, "tree")) {
			this_prefix.name = path;
			traverse_tree(eltbuf, eltsize, &this_prefix);
		} else if (!strcmp(elttype, "blob") && !S_ISLNK(mode)) {
			write_blocked(eltbuf, eltsize);
		}
		free(eltbuf);
	}
}

/* get commit time from committer line of commit object */
static time_t commit_time(void * buffer, unsigned long size)
{
	time_t result = 0;
	char *p = buffer;

	while (size > 0) {
		char *endp = memchr(p, '\n', size);
		if (!endp || endp == p)
			break;
		*endp = '\0';
		if (endp - p > 10 && !memcmp(p, "committer ", 10)) {
			char *nump = strrchr(p, '>');
			if (!nump)
				break;
			nump++;
			result = strtoul(nump, &endp, 10);
			if (*endp != ' ')
				result = 0;
			break;
		}
		size -= endp - p - 1;
		p = endp + 1;
	}
	return result;
}

int main(int argc, char **argv)
{
	unsigned char sha1[20];
	unsigned char commit_sha1[20];
	void *buffer;
	unsigned long size;

	switch (argc) {
	case 3:
		basedir = argv[2];
		/* FALLTHROUGH */
	case 2:
		if (get_sha1(argv[1], sha1) < 0)
			usage(tar_tree_usage);
		break;
	default:
		usage(tar_tree_usage);
	}

	buffer = read_object_with_reference(sha1, "commit", &size, commit_sha1);
	if (buffer) {
		write_global_extended_header(commit_sha1);
		archive_time = commit_time(buffer, size);
		free(buffer);
	}
	buffer = read_object_with_reference(sha1, "tree", &size, NULL);
	if (!buffer)
		die("not a reference to a tag, commit or tree object: %s",
		    sha1_to_hex(sha1));
	if (!archive_time)
		archive_time = time(NULL);
	if (basedir)
		write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
			basedir, 040755, NULL, 0);
	traverse_tree(buffer, size, NULL);
	free(buffer);
	write_trailer();
	return 0;
}
Commit	Line	Data
92747a90 PB	1	/*
	2	* Copyright (c) 2005 Rene Scharfe
	3	*/
731ab9cc RS	4	#include <time.h>
	5	#include "cache.h"
	6
	7	#define RECORDSIZE (512)
	8	#define BLOCKSIZE (RECORDSIZE * 20)
	9
03d791ff RS	10	#define TYPEFLAG_AUTO '\0'
03d791ff RS	11	#define TYPEFLAG_REG '0'
d5776d50	12	#define TYPEFLAG_LNK '2'
03d791ff RS	13	#define TYPEFLAG_DIR '5'
	14	#define TYPEFLAG_GLOBAL_HEADER 'g'
	15	#define TYPEFLAG_EXT_HEADER 'x'
	16
d5776d50 RS	17	#define EXT_HEADER_PATH 1
	18	#define EXT_HEADER_LINKPATH 2
	19
4d1f1190	20	static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
731ab9cc RS	21
	22	static char block[BLOCKSIZE];
	23	static unsigned long offset;
	24
	25	static const char *basedir;
	26	static time_t archive_time;
	27
	28	struct path_prefix {
	29	struct path_prefix *prev;
	30	const char *name;
	31	};
	32
	33	/* tries hard to write, either succeeds or dies in the attempt */
	34	static void reliable_write(void *buf, unsigned long size)
	35	{
	36	while (size > 0) {
	37	long ret = write(1, buf, size);
	38	if (ret < 0) {
	39	if (errno == EAGAIN)
	40	continue;
	41	if (errno == EPIPE)
	42	exit(0);
667bb59b	43	die("git-tar-tree: %s", strerror(errno));
731ab9cc	44	} else if (!ret) {
667bb59b	45	die("git-tar-tree: disk full?");
731ab9cc RS	46	}
	47	size -= ret;
	48	buf += ret;
	49	}
	50	}
	51
	52	/* writes out the whole block, but only if it is full */
	53	static void write_if_needed(void)
	54	{
	55	if (offset == BLOCKSIZE) {
	56	reliable_write(block, BLOCKSIZE);
	57	offset = 0;
	58	}
	59	}
	60
a90a6e6a RS	61	/* acquire the next record from the buffer; user must call write_if_needed() */
	62	static char *get_record(void)
	63	{
	64	char *p = block + offset;
	65	memset(p, 0, RECORDSIZE);
	66	offset += RECORDSIZE;
	67	return p;
	68	}
	69
731ab9cc RS	70	/*
	71	* The end of tar archives is marked by 1024 nul bytes and after that
	72	* follows the rest of the block (if any).
	73	*/
	74	static void write_trailer(void)
	75	{
9b5b9f39	76	get_record();
731ab9cc	77	write_if_needed();
9b5b9f39	78	get_record();
731ab9cc	79	write_if_needed();
a325a11b	80	while (offset) {
9b5b9f39 RS	81	get_record();
9b5b9f39 RS	82	write_if_needed();
731ab9cc RS	83	}
	84	}
	85
	86	/*
	87	* queues up writes, so that all our write(2) calls write exactly one
	88	* full block; pads writes to RECORDSIZE
	89	*/
	90	static void write_blocked(void *buf, unsigned long size)
	91	{
	92	unsigned long tail;
	93
	94	if (offset) {
	95	unsigned long chunk = BLOCKSIZE - offset;
	96	if (size < chunk)
	97	chunk = size;
	98	memcpy(block + offset, buf, chunk);
	99	size -= chunk;
	100	offset += chunk;
	101	buf += chunk;
	102	write_if_needed();
	103	}
	104	while (size >= BLOCKSIZE) {
	105	reliable_write(buf, BLOCKSIZE);
	106	size -= BLOCKSIZE;
	107	buf += BLOCKSIZE;
	108	}
	109	if (size) {
	110	memcpy(block + offset, buf, size);
	111	buf += size;
	112	offset += size;
	113	}
	114	tail = offset % RECORDSIZE;
	115	if (tail) {
	116	memset(block + offset, 0, RECORDSIZE - tail);
	117	offset += RECORDSIZE - tail;
	118	}
	119	write_if_needed();
	120	}
	121
	122	static void append_string(char *p, const char s)
	123	{
	124	unsigned int len = strlen(s);
	125	memcpy(*p, s, len);
	126	*p += len;
	127	}
	128
	129	static void append_char(char **p, char c)
	130	{
	131	**p = c;
	132	*p += 1;
	133	}
	134
731ab9cc RS	135	static void append_path_prefix(char *buffer, struct path_prefix prefix)
	136	{
	137	if (!prefix)
	138	return;
	139	append_path_prefix(buffer, prefix->prev);
	140	append_string(buffer, prefix->name);
	141	append_char(buffer, '/');
	142	}
	143
	144	static unsigned int path_prefix_len(struct path_prefix *prefix)
	145	{
	146	if (!prefix)
	147	return 0;
	148	return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
	149	}
	150
	151	static void append_path(char *p, int is_dir, const char basepath,
	152	struct path_prefix prefix, const char path)
	153	{
	154	if (basepath) {
	155	append_string(p, basepath);
	156	append_char(p, '/');
	157	}
	158	append_path_prefix(p, prefix);
	159	append_string(p, path);
	160	if (is_dir)
	161	append_char(p, '/');
	162	}
	163
	164	static unsigned int path_len(int is_dir, const char *basepath,
	165	struct path_prefix prefix, const char path)
	166	{
	167	unsigned int len = 0;
	168	if (basepath)
	169	len += strlen(basepath) + 1;
	170	len += path_prefix_len(prefix) + strlen(path);
	171	if (is_dir)
	172	len++;
	173	return len;
	174	}
	175
71058b1f RS	176	static void append_extended_header_prefix(char **p, unsigned int size,
	177	const char *keyword)
	178	{
	179	int len = sprintf(*p, "%u %s=", size, keyword);
	180	*p += len;
	181	}
	182
	183	static unsigned int extended_header_len(const char *keyword,
	184	unsigned int valuelen)
	185	{
	186	/* "%u %s=%s\n" */
	187	unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
	188	if (len > 9)
	189	len++;
	190	if (len > 99)
	191	len++;
	192	return len;
	193	}
	194
	195	static void append_extended_header(char *p, const char keyword,
	196	const char *value, unsigned int len)
	197	{
	198	unsigned int size = extended_header_len(keyword, len);
	199	append_extended_header_prefix(p, size, keyword);
	200	memcpy(*p, value, len);
	201	*p += len;
	202	append_char(p, '\n');
	203	}
	204
bf0f910d	205	static void write_header(const unsigned char , char, const char , struct path_prefix *,
08f09dac	206	const char , unsigned int, void , unsigned long);
731ab9cc RS	207
	208	/* stores a pax extended header directly in the block buffer */
	209	static void write_extended_header(const char *headerfilename, int is_dir,
08f09dac	210	unsigned int flags, const char *basepath,
731ab9cc	211	struct path_prefix *prefix,
08f09dac RS	212	const char *path, unsigned int namelen,
08f09dac RS	213	void *content, unsigned int contentsize)
731ab9cc	214	{
e7d3dd24	215	char buffer, p;
d5776d50	216	unsigned int pathlen, size, linkpathlen = 0;
71058b1f RS	217
71058b1f RS	218	size = pathlen = extended_header_len("path", namelen);
d5776d50 RS	219	if (flags & EXT_HEADER_LINKPATH) {
	220	linkpathlen = extended_header_len("linkpath", contentsize);
	221	size += linkpathlen;
	222	}
03d791ff	223	write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
08f09dac	224	0100600, NULL, size);
71058b1f	225
e7d3dd24 RS	226	buffer = p = malloc(size);
	227	if (!buffer)
	228	die("git-tar-tree: %s", strerror(errno));
71058b1f	229	append_extended_header_prefix(&p, pathlen, "path");
731ab9cc RS	230	append_path(&p, is_dir, basepath, prefix, path);
731ab9cc RS	231	append_char(&p, '\n');
d5776d50 RS	232	if (flags & EXT_HEADER_LINKPATH)
d5776d50 RS	233	append_extended_header(&p, "linkpath", content, contentsize);
e7d3dd24 RS	234	write_blocked(buffer, size);
e7d3dd24 RS	235	free(buffer);
731ab9cc RS	236	}
731ab9cc RS	237
bf0f910d	238	static void write_global_extended_header(const unsigned char *sha1)
87fec8fc RS	239	{
87fec8fc RS	240	char *p;
71058b1f RS	241	unsigned int size;
	242
	243	size = extended_header_len("comment", 40);
03d791ff	244	write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
08f09dac	245	"pax_global_header", 0100600, NULL, size);
71058b1f	246
a90a6e6a	247	p = get_record();
71058b1f	248	append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
87fec8fc RS	249	write_if_needed();
	250	}
	251
731ab9cc	252	/* stores a ustar header directly in the block buffer */
bf0f910d	253	static void write_header(const unsigned char sha1, char typeflag, const char basepath,
731ab9cc	254	struct path_prefix prefix, const char path,
08f09dac	255	unsigned int mode, void *buffer, unsigned long size)
731ab9cc RS	256	{
731ab9cc RS	257	unsigned int namelen;
d5776d50	258	char *header = NULL;
731ab9cc RS	259	unsigned int checksum = 0;
731ab9cc RS	260	int i;
d5776d50	261	unsigned int ext_header = 0;
731ab9cc	262
03d791ff RS	263	if (typeflag == TYPEFLAG_AUTO) {
	264	if (S_ISDIR(mode))
	265	typeflag = TYPEFLAG_DIR;
d5776d50 RS	266	else if (S_ISLNK(mode))
d5776d50 RS	267	typeflag = TYPEFLAG_LNK;
03d791ff RS	268	else
	269	typeflag = TYPEFLAG_REG;
	270	}
	271
731ab9cc	272	namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
e7d3dd24	273	if (namelen > 100)
d5776d50 RS	274	ext_header \|= EXT_HEADER_PATH;
	275	if (typeflag == TYPEFLAG_LNK && size > 100)
	276	ext_header \|= EXT_HEADER_LINKPATH;
	277
	278	/* the extended header must be written before the normal one */
	279	if (ext_header) {
731ab9cc	280	char headerfilename[51];
d5776d50	281	sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
08f09dac	282	write_extended_header(headerfilename, S_ISDIR(mode),
d5776d50	283	ext_header, basepath, prefix, path,
08f09dac	284	namelen, buffer, size);
d5776d50	285	}
731ab9cc	286
d5776d50 RS	287	header = get_record();
	288
	289	if (ext_header) {
	290	sprintf(header, "%s.data", sha1_to_hex(sha1));
731ab9cc	291	} else {
d5776d50	292	char *p = header;
731ab9cc RS	293	append_path(&p, S_ISDIR(mode), basepath, prefix, path);
	294	}
	295
d5776d50 RS	296	if (typeflag == TYPEFLAG_LNK) {
	297	if (ext_header & EXT_HEADER_LINKPATH) {
	298	sprintf(&header[157], "see %s.paxheader",
	299	sha1_to_hex(sha1));
	300	} else {
	301	if (buffer)
	302	strncpy(&header[157], buffer, size);
	303	}
	304	}
	305
731ab9cc RS	306	if (S_ISDIR(mode))
731ab9cc RS	307	mode \|= 0755; /* GIT doesn't store permissions of dirs */
d5776d50 RS	308	if (S_ISLNK(mode))
d5776d50 RS	309	mode \|= 0777; /* ... nor of symlinks */
731ab9cc RS	310	sprintf(&header[100], "%07o", mode & 07777);
	311
	312	/* XXX: should we provide more meaningful info here? */
	313	sprintf(&header[108], "%07o", 0); /* uid */
	314	sprintf(&header[116], "%07o", 0); /* gid */
	315	strncpy(&header[265], "git", 31); /* uname */
	316	strncpy(&header[297], "git", 31); /* gname */
	317
d5776d50 RS	318	if (S_ISDIR(mode) \|\| S_ISLNK(mode))
	319	size = 0;
	320	sprintf(&header[124], "%011lo", size);
731ab9cc RS	321	sprintf(&header[136], "%011lo", archive_time);
731ab9cc RS	322
87fec8fc	323	header[156] = typeflag;
731ab9cc RS	324
	325	memcpy(&header[257], "ustar", 6);
	326	memcpy(&header[263], "00", 2);
	327
	328	printf(&header[329], "%07o", 0); /* devmajor */
	329	printf(&header[337], "%07o", 0); /* devminor */
	330
	331	memset(&header[148], ' ', 8);
	332	for (i = 0; i < RECORDSIZE; i++)
	333	checksum += header[i];
	334	sprintf(&header[148], "%07o", checksum & 0x1fffff);
	335
	336	write_if_needed();
	337	}
	338
	339	static void traverse_tree(void *buffer, unsigned long size,
	340	struct path_prefix *prefix)
	341	{
	342	struct path_prefix this_prefix;
	343	this_prefix.prev = prefix;
	344
	345	while (size) {
	346	int namelen = strlen(buffer)+1;
	347	void *eltbuf;
	348	char elttype[20];
	349	unsigned long eltsize;
	350	unsigned char *sha1 = buffer + namelen;
	351	char *path = strchr(buffer, ' ') + 1;
	352	unsigned int mode;
	353
	354	if (size < namelen + 20 \|\| sscanf(buffer, "%o", &mode) != 1)
	355	die("corrupt 'tree' file");
	356	buffer = sha1 + 20;
	357	size -= namelen + 20;
	358
	359	eltbuf = read_sha1_file(sha1, elttype, &eltsize);
	360	if (!eltbuf)
	361	die("cannot read %s", sha1_to_hex(sha1));
03d791ff	362	write_header(sha1, TYPEFLAG_AUTO, basedir, prefix, path,
08f09dac	363	mode, eltbuf, eltsize);
731ab9cc RS	364	if (!strcmp(elttype, "tree")) {
	365	this_prefix.name = path;
	366	traverse_tree(eltbuf, eltsize, &this_prefix);
d5776d50	367	} else if (!strcmp(elttype, "blob") && !S_ISLNK(mode)) {
731ab9cc RS	368	write_blocked(eltbuf, eltsize);
	369	}
	370	free(eltbuf);
	371	}
	372	}
	373
	374	/* get commit time from committer line of commit object */
e99d59ff	375	static time_t commit_time(void * buffer, unsigned long size)
731ab9cc	376	{
731ab9cc	377	time_t result = 0;
db413479	378	char *p = buffer;
731ab9cc	379
db413479 RS	380	while (size > 0) {
	381	char *endp = memchr(p, '\n', size);
	382	if (!endp \|\| endp == p)
	383	break;
	384	*endp = '\0';
	385	if (endp - p > 10 && !memcmp(p, "committer ", 10)) {
	386	char *nump = strrchr(p, '>');
	387	if (!nump)
731ab9cc	388	break;
db413479 RS	389	nump++;
	390	result = strtoul(nump, &endp, 10);
	391	if (*endp != ' ')
	392	result = 0;
	393	break;
731ab9cc	394	}
db413479 RS	395	size -= endp - p - 1;
db413479 RS	396	p = endp + 1;
731ab9cc RS	397	}
	398	return result;
	399	}
	400
	401	int main(int argc, char **argv)
	402	{
	403	unsigned char sha1[20];
87fec8fc	404	unsigned char commit_sha1[20];
731ab9cc RS	405	void *buffer;
731ab9cc RS	406	unsigned long size;
731ab9cc RS	407
	408	switch (argc) {
	409	case 3:
	410	basedir = argv[2];
	411	/* FALLTHROUGH */
	412	case 2:
3c249c95	413	if (get_sha1(argv[1], sha1) < 0)
731ab9cc RS	414	usage(tar_tree_usage);
	415	break;
	416	default:
	417	usage(tar_tree_usage);
	418	}
	419
87fec8fc	420	buffer = read_object_with_reference(sha1, "commit", &size, commit_sha1);
db413479	421	if (buffer) {
87fec8fc	422	write_global_extended_header(commit_sha1);
db413479 RS	423	archive_time = commit_time(buffer, size);
	424	free(buffer);
	425	}
	426	buffer = read_object_with_reference(sha1, "tree", &size, NULL);
731ab9cc	427	if (!buffer)
db413479 RS	428	die("not a reference to a tag, commit or tree object: %s",
db413479 RS	429	sha1_to_hex(sha1));
731ab9cc RS	430	if (!archive_time)
	431	archive_time = time(NULL);
	432	if (basedir)
d565b341 MK	433	write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
d565b341 MK	434	basedir, 040755, NULL, 0);
731ab9cc RS	435	traverse_tree(buffer, size, NULL);
	436	free(buffer);
	437	write_trailer();
	438	return 0;
	439	}