archive-tar.c - git - Git at Google

 /*
  * Copyright (c) 2005, 2006 Rene Scharfe
  */
 #include "cache.h"
 #include "commit.h"
 #include "tar.h"
 #include "builtin.h"
 #include "archive.h"

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

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

 static time_t archive_time;
 static int tar_umask = 002;
 static int verbose;
 static const struct commit *commit;
 static size_t base_len;

 /* 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 write_blocked(const void *data, unsigned long size)
 {
 	const char *buf = data;
 	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) {
 		write_or_die(1, buf, BLOCKSIZE);
 		size -= BLOCKSIZE;
 		buf += BLOCKSIZE;
 	}
 	if (size) {
 		memcpy(block + offset, buf, size);
 		offset += size;
 	}
 	tail = offset % RECORDSIZE;
 	if (tail)  {
 		memset(block + offset, 0, RECORDSIZE - tail);
 		offset += RECORDSIZE - tail;
 	}
 	write_if_needed();
 }

 /*
  * 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);
 	}
 }

 /*
  * 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');
 }

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

 static int get_path_prefix(const struct strbuf *path, int maxlen)
 {
 	int i = path->len;
 	if (i > maxlen)
 		i = maxlen;
 	do {
 		i--;
 	} while (i > 0 && path->buf[i] != '/');
 	return i;
 }

 static void write_entry(const unsigned char *sha1, struct strbuf *path,
                         unsigned int mode, void *buffer, unsigned long size)
 {
 	struct ustar_header header;
 	struct strbuf ext_header;

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

 	if (!sha1) {
 		*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 		mode = 0100666;
 		strcpy(header.name, "pax_global_header");
 	} else if (!path) {
 		*header.typeflag = TYPEFLAG_EXT_HEADER;
 		mode = 0100666;
 		sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 	} else {
 		if (verbose)
 			fprintf(stderr, "%.*s\n", (int)path->len, path->buf);
 		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 {
 			error("unsupported file mode: 0%o (SHA1: %s)",
 			      mode, sha1_to_hex(sha1));
 			return;
 		}
 		if (path->len > sizeof(header.name)) {
 			int plen = get_path_prefix(path, sizeof(header.prefix));
 			int rest = path->len - plen - 1;
 			if (plen > 0 && rest <= sizeof(header.name)) {
 				memcpy(header.prefix, path->buf, plen);
 				memcpy(header.name, path->buf + plen + 1, rest);
 			} else {
 				sprintf(header.name, "%s.data",
 				        sha1_to_hex(sha1));
 				strbuf_append_ext_header(&ext_header, "path",
 				                         path->buf, path->len);
 			}
 		} else
 			memcpy(header.name, path->buf, path->len);
 	}

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

 	sprintf(header.mode, "%07o", mode & 07777);
 	sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 	sprintf(header.mtime, "%011lo", archive_time);

 	sprintf(header.uid, "%07o", 0);
 	sprintf(header.gid, "%07o", 0);
 	strlcpy(header.uname, "root", sizeof(header.uname));
 	strlcpy(header.gname, "root", sizeof(header.gname));
 	sprintf(header.devmajor, "%07o", 0);
 	sprintf(header.devminor, "%07o", 0);

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

 	sprintf(header.chksum, "%07o", ustar_header_chksum(&header));

 	if (ext_header.len > 0) {
 		write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 	}
 	strbuf_release(&ext_header);
 	write_blocked(&header, sizeof(header));
 	if (S_ISREG(mode) && buffer && size > 0)
 		write_blocked(buffer, size);
 }

 static void write_global_extended_header(const unsigned char *sha1)
 {
 	struct strbuf ext_header;

 	strbuf_init(&ext_header, 0);
 	strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 	write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 	strbuf_release(&ext_header);
 }

 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 git_default_config(var, value, cb);
 }

 static int write_tar_entry(const unsigned char *sha1,
                            const char *base, int baselen,
                            const char *filename, unsigned mode, int stage)
 {
 	static struct strbuf path = STRBUF_INIT;
 	void *buffer;
 	enum object_type type;
 	unsigned long size;

 	strbuf_reset(&path);
 	strbuf_grow(&path, PATH_MAX);
 	strbuf_add(&path, base, baselen);
 	strbuf_addstr(&path, filename);
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 		strbuf_addch(&path, '/');
 		buffer = NULL;
 		size = 0;
 	} else {
 		buffer = sha1_file_to_archive(path.buf + base_len, sha1, mode,
 				&type, &size, commit);
 		if (!buffer)
 			die("cannot read %s", sha1_to_hex(sha1));
 	}

 	write_entry(sha1, &path, mode, buffer, size);
 	free(buffer);

 	return READ_TREE_RECURSIVE;
 }

 int write_tar_archive(struct archiver_args *args)
 {
 	int plen = args->base ? strlen(args->base) : 0;

 	git_config(git_tar_config, NULL);

 	archive_time = args->time;
 	verbose = args->verbose;
 	commit = args->commit;
 	base_len = args->base ? strlen(args->base) : 0;

 	if (args->commit_sha1)
 		write_global_extended_header(args->commit_sha1);

 	if (args->base && plen > 0 && args->base[plen - 1] == '/') {
 		char *base = xstrdup(args->base);
 		int baselen = strlen(base);

 		while (baselen > 0 && base[baselen - 1] == '/')
 			base[--baselen] = '\0';
 		write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
 		free(base);
 	}
 	read_tree_recursive(args->tree, args->base, plen, 0,
 			    args->pathspec, write_tar_entry);
 	write_trailer();

 	return 0;
 }
	/*
	* Copyright (c) 2005, 2006 Rene Scharfe
	*/
	#include "cache.h"
	#include "commit.h"
	#include "tar.h"
	#include "builtin.h"
	#include "archive.h"

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

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

	static time_t archive_time;
	static int tar_umask = 002;
	static int verbose;
	static const struct commit *commit;
	static size_t base_len;

	/* 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 write_blocked(const void *data, unsigned long size)
	{
	const char *buf = data;
	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) {
	write_or_die(1, buf, BLOCKSIZE);
	size -= BLOCKSIZE;
	buf += BLOCKSIZE;
	}
	if (size) {
	memcpy(block + offset, buf, size);
	offset += size;
	}
	tail = offset % RECORDSIZE;
	if (tail) {
	memset(block + offset, 0, RECORDSIZE - tail);
	offset += RECORDSIZE - tail;
	}
	write_if_needed();
	}

	/*
	* 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);
	}
	}

	/*
	* 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');
	}

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

	static int get_path_prefix(const struct strbuf *path, int maxlen)
	{
	int i = path->len;
	if (i > maxlen)
	i = maxlen;
	do {
	i--;
	} while (i > 0 && path->buf[i] != '/');
	return i;
	}

	static void write_entry(const unsigned char sha1, struct strbuf path,
	unsigned int mode, void *buffer, unsigned long size)
	{
	struct ustar_header header;
	struct strbuf ext_header;

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

	if (!sha1) {
	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
	mode = 0100666;
	strcpy(header.name, "pax_global_header");
	} else if (!path) {
	*header.typeflag = TYPEFLAG_EXT_HEADER;
	mode = 0100666;
	sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
	} else {
	if (verbose)
	fprintf(stderr, "%.*s\n", (int)path->len, path->buf);
	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 {
	error("unsupported file mode: 0%o (SHA1: %s)",
	mode, sha1_to_hex(sha1));
	return;
	}
	if (path->len > sizeof(header.name)) {
	int plen = get_path_prefix(path, sizeof(header.prefix));
	int rest = path->len - plen - 1;
	if (plen > 0 && rest <= sizeof(header.name)) {
	memcpy(header.prefix, path->buf, plen);
	memcpy(header.name, path->buf + plen + 1, rest);
	} else {
	sprintf(header.name, "%s.data",
	sha1_to_hex(sha1));
	strbuf_append_ext_header(&ext_header, "path",
	path->buf, path->len);
	}
	} else
	memcpy(header.name, path->buf, path->len);
	}

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

	sprintf(header.mode, "%07o", mode & 07777);
	sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
	sprintf(header.mtime, "%011lo", archive_time);

	sprintf(header.uid, "%07o", 0);
	sprintf(header.gid, "%07o", 0);
	strlcpy(header.uname, "root", sizeof(header.uname));
	strlcpy(header.gname, "root", sizeof(header.gname));
	sprintf(header.devmajor, "%07o", 0);
	sprintf(header.devminor, "%07o", 0);

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

	sprintf(header.chksum, "%07o", ustar_header_chksum(&header));

	if (ext_header.len > 0) {
	write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
	}
	strbuf_release(&ext_header);
	write_blocked(&header, sizeof(header));
	if (S_ISREG(mode) && buffer && size > 0)
	write_blocked(buffer, size);
	}

	static void write_global_extended_header(const unsigned char *sha1)
	{
	struct strbuf ext_header;

	strbuf_init(&ext_header, 0);
	strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
	write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
	strbuf_release(&ext_header);
	}

	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 git_default_config(var, value, cb);
	}

	static int write_tar_entry(const unsigned char *sha1,
	const char *base, int baselen,
	const char *filename, unsigned mode, int stage)
	{
	static struct strbuf path = STRBUF_INIT;
	void *buffer;
	enum object_type type;
	unsigned long size;

	strbuf_reset(&path);
	strbuf_grow(&path, PATH_MAX);
	strbuf_add(&path, base, baselen);
	strbuf_addstr(&path, filename);
	if (S_ISDIR(mode) \|\| S_ISGITLINK(mode)) {
	strbuf_addch(&path, '/');
	buffer = NULL;
	size = 0;
	} else {
	buffer = sha1_file_to_archive(path.buf + base_len, sha1, mode,
	&type, &size, commit);
	if (!buffer)
	die("cannot read %s", sha1_to_hex(sha1));
	}

	write_entry(sha1, &path, mode, buffer, size);
	free(buffer);

	return READ_TREE_RECURSIVE;
	}

	int write_tar_archive(struct archiver_args *args)
	{
	int plen = args->base ? strlen(args->base) : 0;

	git_config(git_tar_config, NULL);

	archive_time = args->time;
	verbose = args->verbose;
	commit = args->commit;
	base_len = args->base ? strlen(args->base) : 0;

	if (args->commit_sha1)
	write_global_extended_header(args->commit_sha1);

	if (args->base && plen > 0 && args->base[plen - 1] == '/') {
	char *base = xstrdup(args->base);
	int baselen = strlen(base);

	while (baselen > 0 && base[baselen - 1] == '/')
	base[--baselen] = '\0';
	write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
	free(base);
	}
	read_tree_recursive(args->tree, args->base, plen, 0,
	args->pathspec, write_tar_entry);
	write_trailer();

	return 0;
	}