update-cache.c - jrn/git - Git at Google

 /*
  * GIT - The information manager from hell
  *
  * Copyright (C) Linus Torvalds, 2005
  */
 #include <signal.h>
 #include "cache.h"

 /*
  * Default to not allowing changes to the list of files. The
  * tool doesn't actually care, but this makes it harder to add
  * files to the revision control by mistake by doing something
  * like "update-cache *" and suddenly having all the object
  * files be revision controlled.
  */
 static int allow_add = 0, allow_remove = 0, not_new = 0;

 /* Three functions to allow overloaded pointer return; see linux/err.h */
 static inline void *ERR_PTR(long error)
 {
 	return (void *) error;
 }

 static inline long PTR_ERR(const void *ptr)
 {
 	return (long) ptr;
 }

 static inline long IS_ERR(const void *ptr)
 {
 	return (unsigned long)ptr > (unsigned long)-1000L;
 }

 static int index_fd(unsigned char *sha1, int fd, struct stat *st)
 {
 	z_stream stream;
 	unsigned long size = st->st_size;
 	int max_out_bytes = size + 200;
 	void *out = xmalloc(max_out_bytes);
 	void *metadata = xmalloc(200);
 	int metadata_size;
 	void *in;
 	SHA_CTX c;

 	in = "";
 	if (size)
 		in = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 	close(fd);
 	if (!out || (int)(long)in == -1)
 		return -1;

 	metadata_size = 1+sprintf(metadata, "blob %lu", size);

 	SHA1_Init(&c);
 	SHA1_Update(&c, metadata, metadata_size);
 	SHA1_Update(&c, in, size);
 	SHA1_Final(sha1, &c);

 	memset(&stream, 0, sizeof(stream));
 	deflateInit(&stream, Z_BEST_COMPRESSION);

 	/*
 	 * ASCII size + nul byte
 	 */
 	stream.next_in = metadata;
 	stream.avail_in = metadata_size;
 	stream.next_out = out;
 	stream.avail_out = max_out_bytes;
 	while (deflate(&stream, 0) == Z_OK)
 		/* nothing */;

 	/*
 	 * File content
 	 */
 	stream.next_in = in;
 	stream.avail_in = size;
 	while (deflate(&stream, Z_FINISH) == Z_OK)
 		/*nothing */;

 	deflateEnd(&stream);

 	return write_sha1_buffer(sha1, out, stream.total_out);
 }

 /*
  * This only updates the "non-critical" parts of the directory
  * cache, ie the parts that aren't tracked by GIT, and only used
  * to validate the cache.
  */
 static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 {
 	ce->ce_ctime.sec = htonl(st->st_ctime);
 	ce->ce_mtime.sec = htonl(st->st_mtime);
 #ifdef NSEC
 	ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
 	ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
 #endif
 	ce->ce_dev = htonl(st->st_dev);
 	ce->ce_ino = htonl(st->st_ino);
 	ce->ce_uid = htonl(st->st_uid);
 	ce->ce_gid = htonl(st->st_gid);
 	ce->ce_size = htonl(st->st_size);
 }

 static int add_file_to_cache(char *path)
 {
 	int size, namelen;
 	struct cache_entry *ce;
 	struct stat st;
 	int fd;

 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
 		if (errno == ENOENT) {
 			if (allow_remove)
 				return remove_file_from_cache(path);
 		}
 		return -1;
 	}
 	if (fstat(fd, &st) < 0) {
 		close(fd);
 		return -1;
 	}
 	namelen = strlen(path);
 	size = cache_entry_size(namelen);
 	ce = xmalloc(size);
 	memset(ce, 0, size);
 	memcpy(ce->name, path, namelen);
 	fill_stat_cache_info(ce, &st);
 	ce->ce_mode = create_ce_mode(st.st_mode);
 	ce->ce_flags = htons(namelen);

 	if (index_fd(ce->sha1, fd, &st) < 0)
 		return -1;

 	return add_cache_entry(ce, allow_add);
 }

 static int match_data(int fd, void *buffer, unsigned long size)
 {
 	while (size) {
 		char compare[1024];
 		int ret = read(fd, compare, sizeof(compare));

 		if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 			return -1;
 		size -= ret;
 		buffer += ret;
 	}
 	return 0;
 }

 static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 {
 	int match = -1;
 	int fd = open(ce->name, O_RDONLY);

 	if (fd >= 0) {
 		void *buffer;
 		unsigned long size;
 		char type[10];

 		buffer = read_sha1_file(ce->sha1, type, &size);
 		if (buffer) {
 			if (size == expected_size && !strcmp(type, "blob"))
 				match = match_data(fd, buffer, size);
 			free(buffer);
 		}
 		close(fd);
 	}
 	return match;
 }

 /*
  * "refresh" does not calculate a new sha1 file or bring the
  * cache up-to-date for mode/content changes. But what it
  * _does_ do is to "re-match" the stat information of a file
  * with the cache, so that you can refresh the cache for a
  * file that hasn't been changed but where the stat entry is
  * out of date.
  *
  * For example, you'd want to do this after doing a "read-tree",
  * to link up the stat cache details with the proper files.
  */
 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 {
 	struct stat st;
 	struct cache_entry *updated;
 	int changed, size;

 	if (stat(ce->name, &st) < 0)
 		return ERR_PTR(-errno);

 	changed = cache_match_stat(ce, &st);
 	if (!changed)
 		return ce;

 	/*
 	 * If the mode has changed, there's no point in trying
 	 * to refresh the entry - it's not going to match
 	 */
 	if (changed & MODE_CHANGED)
 		return ERR_PTR(-EINVAL);

 	if (compare_data(ce, st.st_size))
 		return ERR_PTR(-EINVAL);

 	size = ce_size(ce);
 	updated = xmalloc(size);
 	memcpy(updated, ce, size);
 	fill_stat_cache_info(updated, &st);
 	return updated;
 }

 static void refresh_cache(void)
 {
 	int i;

 	for (i = 0; i < active_nr; i++) {
 		struct cache_entry *ce, *new;
 		ce = active_cache[i];
 		if (ce_stage(ce)) {
 			printf("%s: needs merge\n", ce->name);
 			while ((i < active_nr) &&
 			       ! strcmp(active_cache[i]->name, ce->name))
 				i++;
 			i--;
 			continue;
 		}

 		new = refresh_entry(ce);
 		if (IS_ERR(new)) {
 			if (!(not_new && PTR_ERR(new) == -ENOENT))
 				printf("%s: needs update\n", ce->name);
 			continue;
 		}
 		active_cache[i] = new;
 	}
 }

 /*
  * We fundamentally don't like some paths: we don't want
  * dot or dot-dot anywhere, and in fact, we don't even want
  * any other dot-files (.git or anything else). They
  * are hidden, for chist sake.
  *
  * Also, we don't want double slashes or slashes at the
  * end that can make pathnames ambiguous.
  */
 static int verify_path(char *path)
 {
 	char c;

 	goto inside;
 	for (;;) {
 		if (!c)
 			return 1;
 		if (c == '/') {
 inside:
 			c = *path++;
 			if (c != '/' && c != '.' && c != '\0')
 				continue;
 			return 0;
 		}
 		c = *path++;
 	}
 }

 static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 {
 	int size, len;
 	unsigned int mode;
 	unsigned char sha1[20];
 	struct cache_entry *ce;

 	if (sscanf(arg1, "%o", &mode) != 1)
 		return -1;
 	if (get_sha1_hex(arg2, sha1))
 		return -1;
 	if (!verify_path(arg3))
 		return -1;

 	len = strlen(arg3);
 	size = cache_entry_size(len);
 	ce = xmalloc(size);
 	memset(ce, 0, size);

 	memcpy(ce->sha1, sha1, 20);
 	memcpy(ce->name, arg3, len);
 	ce->ce_flags = htons(len);
 	ce->ce_mode = create_ce_mode(mode);
 	return add_cache_entry(ce, allow_add);
 }

 static const char *lockfile_name = NULL;

 static void remove_lock_file(void)
 {
 	if (lockfile_name)
 		unlink(lockfile_name);
 }

 static void remove_lock_file_on_signal(int signo)
 {
 	remove_lock_file();
 }

 int main(int argc, char **argv)
 {
 	int i, newfd, entries;
 	int allow_options = 1;
 	static char lockfile[MAXPATHLEN+1];
 	const char *indexfile = get_index_file();

 	snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);

 	newfd = open(lockfile, O_RDWR | O_CREAT | O_EXCL, 0600);
 	if (newfd < 0)
 		die("unable to create new cachefile");

 	signal(SIGINT, remove_lock_file_on_signal);
 	atexit(remove_lock_file);
 	lockfile_name = lockfile;

 	entries = read_cache();
 	if (entries < 0)
 		die("cache corrupted");

 	for (i = 1 ; i < argc; i++) {
 		char *path = argv[i];

 		if (allow_options && *path == '-') {
 			if (!strcmp(path, "--")) {
 				allow_options = 0;
 				continue;
 			}
 			if (!strcmp(path, "--add")) {
 				allow_add = 1;
 				continue;
 			}
 			if (!strcmp(path, "--remove")) {
 				allow_remove = 1;
 				continue;
 			}
 			if (!strcmp(path, "--refresh")) {
 				refresh_cache();
 				continue;
 			}
 			if (!strcmp(path, "--cacheinfo")) {
 				if (i+3 >= argc || add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
 					die("update-cache: --cacheinfo <mode> <sha1> <path>");
 				i += 3;
 				continue;
 			}
 			if (!strcmp(path, "--ignore-missing")) {
 				not_new = 1;
 				continue;
 			}
 			die("unknown option %s", path);
 		}
 		if (!verify_path(path)) {
 			fprintf(stderr, "Ignoring path %s\n", argv[i]);
 			continue;
 		}
 		if (add_file_to_cache(path))
 			die("Unable to add %s to database", path);
 	}
 	if (write_cache(newfd, active_cache, active_nr) || rename(lockfile, indexfile))
 		die("Unable to write new cachefile");

 	lockfile_name = NULL;
 	return 0;
 }
	/*
	* GIT - The information manager from hell
	*
	* Copyright (C) Linus Torvalds, 2005
	*/
	#include <signal.h>
	#include "cache.h"

	/*
	* Default to not allowing changes to the list of files. The
	* tool doesn't actually care, but this makes it harder to add
	* files to the revision control by mistake by doing something
	* like "update-cache *" and suddenly having all the object
	* files be revision controlled.
	*/
	static int allow_add = 0, allow_remove = 0, not_new = 0;

	/* Three functions to allow overloaded pointer return; see linux/err.h */
	static inline void *ERR_PTR(long error)
	{
	return (void *) error;
	}

	static inline long PTR_ERR(const void *ptr)
	{
	return (long) ptr;
	}

	static inline long IS_ERR(const void *ptr)
	{
	return (unsigned long)ptr > (unsigned long)-1000L;
	}

	static int index_fd(unsigned char sha1, int fd, struct stat st)
	{
	z_stream stream;
	unsigned long size = st->st_size;
	int max_out_bytes = size + 200;
	void *out = xmalloc(max_out_bytes);
	void *metadata = xmalloc(200);
	int metadata_size;
	void *in;
	SHA_CTX c;

	in = "";
	if (size)
	in = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	close(fd);
	if (!out \|\| (int)(long)in == -1)
	return -1;

	metadata_size = 1+sprintf(metadata, "blob %lu", size);

	SHA1_Init(&c);
	SHA1_Update(&c, metadata, metadata_size);
	SHA1_Update(&c, in, size);
	SHA1_Final(sha1, &c);

	memset(&stream, 0, sizeof(stream));
	deflateInit(&stream, Z_BEST_COMPRESSION);

	/*
	* ASCII size + nul byte
	*/
	stream.next_in = metadata;
	stream.avail_in = metadata_size;
	stream.next_out = out;
	stream.avail_out = max_out_bytes;
	while (deflate(&stream, 0) == Z_OK)
	/* nothing */;

	/*
	* File content
	*/
	stream.next_in = in;
	stream.avail_in = size;
	while (deflate(&stream, Z_FINISH) == Z_OK)
	/nothing /;

	deflateEnd(&stream);

	return write_sha1_buffer(sha1, out, stream.total_out);
	}

	/*
	* This only updates the "non-critical" parts of the directory
	* cache, ie the parts that aren't tracked by GIT, and only used
	* to validate the cache.
	*/
	static void fill_stat_cache_info(struct cache_entry ce, struct stat st)
	{
	ce->ce_ctime.sec = htonl(st->st_ctime);
	ce->ce_mtime.sec = htonl(st->st_mtime);
	#ifdef NSEC
	ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
	ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
	#endif
	ce->ce_dev = htonl(st->st_dev);
	ce->ce_ino = htonl(st->st_ino);
	ce->ce_uid = htonl(st->st_uid);
	ce->ce_gid = htonl(st->st_gid);
	ce->ce_size = htonl(st->st_size);
	}

	static int add_file_to_cache(char *path)
	{
	int size, namelen;
	struct cache_entry *ce;
	struct stat st;
	int fd;

	fd = open(path, O_RDONLY);
	if (fd < 0) {
	if (errno == ENOENT) {
	if (allow_remove)
	return remove_file_from_cache(path);
	}
	return -1;
	}
	if (fstat(fd, &st) < 0) {
	close(fd);
	return -1;
	}
	namelen = strlen(path);
	size = cache_entry_size(namelen);
	ce = xmalloc(size);
	memset(ce, 0, size);
	memcpy(ce->name, path, namelen);
	fill_stat_cache_info(ce, &st);
	ce->ce_mode = create_ce_mode(st.st_mode);
	ce->ce_flags = htons(namelen);

	if (index_fd(ce->sha1, fd, &st) < 0)
	return -1;

	return add_cache_entry(ce, allow_add);
	}

	static int match_data(int fd, void *buffer, unsigned long size)
	{
	while (size) {
	char compare[1024];
	int ret = read(fd, compare, sizeof(compare));

	if (ret <= 0 \|\| ret > size \|\| memcmp(buffer, compare, ret))
	return -1;
	size -= ret;
	buffer += ret;
	}
	return 0;
	}

	static int compare_data(struct cache_entry *ce, unsigned long expected_size)
	{
	int match = -1;
	int fd = open(ce->name, O_RDONLY);

	if (fd >= 0) {
	void *buffer;
	unsigned long size;
	char type[10];

	buffer = read_sha1_file(ce->sha1, type, &size);
	if (buffer) {
	if (size == expected_size && !strcmp(type, "blob"))
	match = match_data(fd, buffer, size);
	free(buffer);
	}
	close(fd);
	}
	return match;
	}

	/*
	* "refresh" does not calculate a new sha1 file or bring the
	* cache up-to-date for mode/content changes. But what it
	* _does_ do is to "re-match" the stat information of a file
	* with the cache, so that you can refresh the cache for a
	* file that hasn't been changed but where the stat entry is
	* out of date.
	*
	* For example, you'd want to do this after doing a "read-tree",
	* to link up the stat cache details with the proper files.
	*/
	static struct cache_entry refresh_entry(struct cache_entry ce)
	{
	struct stat st;
	struct cache_entry *updated;
	int changed, size;

	if (stat(ce->name, &st) < 0)
	return ERR_PTR(-errno);

	changed = cache_match_stat(ce, &st);
	if (!changed)
	return ce;

	/*
	* If the mode has changed, there's no point in trying
	* to refresh the entry - it's not going to match
	*/
	if (changed & MODE_CHANGED)
	return ERR_PTR(-EINVAL);

	if (compare_data(ce, st.st_size))
	return ERR_PTR(-EINVAL);

	size = ce_size(ce);
	updated = xmalloc(size);
	memcpy(updated, ce, size);
	fill_stat_cache_info(updated, &st);
	return updated;
	}

	static void refresh_cache(void)
	{
	int i;

	for (i = 0; i < active_nr; i++) {
	struct cache_entry ce, new;
	ce = active_cache[i];
	if (ce_stage(ce)) {
	printf("%s: needs merge\n", ce->name);
	while ((i < active_nr) &&
	! strcmp(active_cache[i]->name, ce->name))
	i++;
	i--;
	continue;
	}

	new = refresh_entry(ce);
	if (IS_ERR(new)) {
	if (!(not_new && PTR_ERR(new) == -ENOENT))
	printf("%s: needs update\n", ce->name);
	continue;
	}
	active_cache[i] = new;
	}
	}

	/*
	* We fundamentally don't like some paths: we don't want
	* dot or dot-dot anywhere, and in fact, we don't even want
	* any other dot-files (.git or anything else). They
	* are hidden, for chist sake.
	*
	* Also, we don't want double slashes or slashes at the
	* end that can make pathnames ambiguous.
	*/
	static int verify_path(char *path)
	{
	char c;

	goto inside;
	for (;;) {
	if (!c)
	return 1;
	if (c == '/') {
	inside:
	c = *path++;
	if (c != '/' && c != '.' && c != '\0')
	continue;
	return 0;
	}
	c = *path++;
	}
	}

	static int add_cacheinfo(char arg1, char arg2, char *arg3)
	{
	int size, len;
	unsigned int mode;
	unsigned char sha1[20];
	struct cache_entry *ce;

	if (sscanf(arg1, "%o", &mode) != 1)
	return -1;
	if (get_sha1_hex(arg2, sha1))
	return -1;
	if (!verify_path(arg3))
	return -1;

	len = strlen(arg3);
	size = cache_entry_size(len);
	ce = xmalloc(size);
	memset(ce, 0, size);

	memcpy(ce->sha1, sha1, 20);
	memcpy(ce->name, arg3, len);
	ce->ce_flags = htons(len);
	ce->ce_mode = create_ce_mode(mode);
	return add_cache_entry(ce, allow_add);
	}

	static const char *lockfile_name = NULL;

	static void remove_lock_file(void)
	{
	if (lockfile_name)
	unlink(lockfile_name);
	}

	static void remove_lock_file_on_signal(int signo)
	{
	remove_lock_file();
	}

	int main(int argc, char **argv)
	{
	int i, newfd, entries;
	int allow_options = 1;
	static char lockfile[MAXPATHLEN+1];
	const char *indexfile = get_index_file();

	snprintf(lockfile, sizeof(lockfile), "%s.lock", indexfile);

	newfd = open(lockfile, O_RDWR \| O_CREAT \| O_EXCL, 0600);
	if (newfd < 0)
	die("unable to create new cachefile");

	signal(SIGINT, remove_lock_file_on_signal);
	atexit(remove_lock_file);
	lockfile_name = lockfile;

	entries = read_cache();
	if (entries < 0)
	die("cache corrupted");

	for (i = 1 ; i < argc; i++) {
	char *path = argv[i];

	if (allow_options && *path == '-') {
	if (!strcmp(path, "--")) {
	allow_options = 0;
	continue;
	}
	if (!strcmp(path, "--add")) {
	allow_add = 1;
	continue;
	}
	if (!strcmp(path, "--remove")) {
	allow_remove = 1;
	continue;
	}
	if (!strcmp(path, "--refresh")) {
	refresh_cache();
	continue;
	}
	if (!strcmp(path, "--cacheinfo")) {
	if (i+3 >= argc \|\| add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
	die("update-cache: --cacheinfo <mode> <sha1> <path>");
	i += 3;
	continue;
	}
	if (!strcmp(path, "--ignore-missing")) {
	not_new = 1;
	continue;
	}
	die("unknown option %s", path);
	}
	if (!verify_path(path)) {
	fprintf(stderr, "Ignoring path %s\n", argv[i]);
	continue;
	}
	if (add_file_to_cache(path))
	die("Unable to add %s to database", path);
	}
	if (write_cache(newfd, active_cache, active_nr) \|\| rename(lockfile, indexfile))
	die("Unable to write new cachefile");

	lockfile_name = NULL;
	return 0;
	}