[thirdparty/git.git] / read-cache.c

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

const char *sha1_file_directory = NULL;
struct cache_entry **active_cache = NULL;
unsigned int active_nr = 0, active_alloc = 0;

void usage(const char *err)
{
	fprintf(stderr, "read-tree: %s\n", err);
	exit(1);
}

static unsigned hexval(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	if (c >= 'A' && c <= 'F')
		return c - 'A' + 10;
	return ~0;
}

int get_sha1_hex(char *hex, unsigned char *sha1)
{
	int i;
	for (i = 0; i < 20; i++) {
		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
		if (val & ~0xff)
			return -1;
		*sha1++ = val;
		hex += 2;
	}
	return 0;
}

char * sha1_to_hex(unsigned char *sha1)
{
	static char buffer[50];
	static const char hex[] = "0123456789abcdef";
	char *buf = buffer;
	int i;

	for (i = 0; i < 20; i++) {
		unsigned int val = *sha1++;
		*buf++ = hex[val >> 4];
		*buf++ = hex[val & 0xf];
	}
	return buffer;
}

/*
 * NOTE! This returns a statically allocated buffer, so you have to be
 * careful about using it. Do a "strdup()" if you need to save the
 * filename.
 */
char *sha1_file_name(unsigned char *sha1)
{
	int i;
	static char *name, *base;

	if (!base) {
		char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
		int len = strlen(sha1_file_directory);
		base = malloc(len + 60);
		memcpy(base, sha1_file_directory, len);
		memset(base+len, 0, 60);
		base[len] = '/';
		base[len+3] = '/';
		name = base + len + 1;
	}
	for (i = 0; i < 20; i++) {
		static char hex[] = "0123456789abcdef";
		unsigned int val = sha1[i];
		char *pos = name + i*2 + (i > 0);
		*pos++ = hex[val >> 4];
		*pos = hex[val & 0xf];
	}
	return base;
}

void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
{
	z_stream stream;
	char buffer[8192];
	struct stat st;
	int fd, ret, bytes;
	void *map, *buf;
	char *filename = sha1_file_name(sha1);

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror(filename);
		return NULL;
	}
	if (fstat(fd, &st) < 0) {
		close(fd);
		return NULL;
	}
	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	close(fd);
	if (-1 == (int)(long)map)
		return NULL;

	/* Get the data stream */
	memset(&stream, 0, sizeof(stream));
	stream.next_in = map;
	stream.avail_in = st.st_size;
	stream.next_out = buffer;
	stream.avail_out = sizeof(buffer);

	inflateInit(&stream);
	ret = inflate(&stream, 0);
	if (sscanf(buffer, "%10s %lu", type, size) != 2)
		return NULL;
	bytes = strlen(buffer) + 1;
	buf = malloc(*size);
	if (!buf)
		return NULL;

	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	bytes = stream.total_out - bytes;
	if (bytes < *size && ret == Z_OK) {
		stream.next_out = buf + bytes;
		stream.avail_out = *size - bytes;
		while (inflate(&stream, Z_FINISH) == Z_OK)
			/* nothing */;
	}
	inflateEnd(&stream);
	return buf;
}

int write_sha1_file(char *buf, unsigned len)
{
	int size;
	char *compressed;
	z_stream stream;
	unsigned char sha1[20];
	SHA_CTX c;

	/* Set it up */
	memset(&stream, 0, sizeof(stream));
	deflateInit(&stream, Z_BEST_COMPRESSION);
	size = deflateBound(&stream, len);
	compressed = malloc(size);

	/* Compress it */
	stream.next_in = buf;
	stream.avail_in = len;
	stream.next_out = compressed;
	stream.avail_out = size;
	while (deflate(&stream, Z_FINISH) == Z_OK)
		/* nothing */;
	deflateEnd(&stream);
	size = stream.total_out;

	/* Sha1.. */
	SHA1_Init(&c);
	SHA1_Update(&c, compressed, size);
	SHA1_Final(sha1, &c);

	if (write_sha1_buffer(sha1, compressed, size) < 0)
		return -1;
	printf("%s\n", sha1_to_hex(sha1));
	return 0;
}

int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
{
	char *filename = sha1_file_name(sha1);
	int fd;

	fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
	if (fd < 0)
		return (errno == EEXIST) ? 0 : -1;
	write(fd, buf, size);
	close(fd);
	return 0;
}

static int error(const char * string)
{
	fprintf(stderr, "error: %s\n", string);
	return -1;
}

static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
	SHA_CTX c;
	unsigned char sha1[20];

	if (hdr->signature != CACHE_SIGNATURE)
		return error("bad signature");
	if (hdr->version != 1)
		return error("bad version");
	SHA1_Init(&c);
	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	SHA1_Final(sha1, &c);
	if (memcmp(sha1, hdr->sha1, 20))
		return error("bad header sha1");
	return 0;
}

int read_cache(void)
{
	int fd, i;
	struct stat st;
	unsigned long size, offset;
	void *map;
	struct cache_header *hdr;

	errno = EBUSY;
	if (active_cache)
		return error("more than one cachefile");
	errno = ENOENT;
	sha1_file_directory = getenv(DB_ENVIRONMENT);
	if (!sha1_file_directory)
		sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	if (access(sha1_file_directory, X_OK) < 0)
		return error("no access to SHA1 file directory");
	fd = open(".dircache/index", O_RDONLY);
	if (fd < 0)
		return (errno == ENOENT) ? 0 : error("open failed");

	size = 0; // avoid gcc warning
	map = (void *)-1;
	if (!fstat(fd, &st)) {
		map = NULL;
		size = st.st_size;
		errno = EINVAL;
		if (size > sizeof(struct cache_header))
			map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	}
	close(fd);
	if (-1 == (int)(long)map)
		return error("mmap failed");

	hdr = map;
	if (verify_hdr(hdr, size) < 0)
		goto unmap;

	active_nr = hdr->entries;
	active_alloc = alloc_nr(active_nr);
	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));

	offset = sizeof(*hdr);
	for (i = 0; i < hdr->entries; i++) {
		struct cache_entry *ce = map + offset;
		offset = offset + ce_size(ce);
		active_cache[i] = ce;
	}
	return active_nr;

unmap:
	munmap(map, size);
	errno = EINVAL;
	return error("verify header failed");
}
Commit	Line	Data
8bc9a0c7 LT	1	/*
	2	* GIT - The information manager from hell
	3	*
	4	* Copyright (C) Linus Torvalds, 2005
	5	*/
e83c5163 LT	6	#include "cache.h"
	7
	8	const char *sha1_file_directory = NULL;
	9	struct cache_entry **active_cache = NULL;
	10	unsigned int active_nr = 0, active_alloc = 0;
	11
	12	void usage(const char *err)
	13	{
	14	fprintf(stderr, "read-tree: %s\n", err);
	15	exit(1);
	16	}
	17
	18	static unsigned hexval(char c)
	19	{
	20	if (c >= '0' && c <= '9')
	21	return c - '0';
	22	if (c >= 'a' && c <= 'f')
	23	return c - 'a' + 10;
	24	if (c >= 'A' && c <= 'F')
	25	return c - 'A' + 10;
	26	return ~0;
	27	}
	28
	29	int get_sha1_hex(char hex, unsigned char sha1)
	30	{
	31	int i;
	32	for (i = 0; i < 20; i++) {
	33	unsigned int val = (hexval(hex[0]) << 4) \| hexval(hex[1]);
	34	if (val & ~0xff)
	35	return -1;
	36	*sha1++ = val;
	37	hex += 2;
	38	}
	39	return 0;
	40	}
	41
	42	char * sha1_to_hex(unsigned char *sha1)
	43	{
	44	static char buffer[50];
	45	static const char hex[] = "0123456789abcdef";
	46	char *buf = buffer;
	47	int i;
	48
	49	for (i = 0; i < 20; i++) {
	50	unsigned int val = *sha1++;
	51	*buf++ = hex[val >> 4];
	52	*buf++ = hex[val & 0xf];
	53	}
	54	return buffer;
	55	}
	56
	57	/*
	58	* NOTE! This returns a statically allocated buffer, so you have to be
	59	* careful about using it. Do a "strdup()" if you need to save the
	60	* filename.
	61	*/
	62	char sha1_file_name(unsigned char sha1)
	63	{
	64	int i;
	65	static char name, base;
	66
	67	if (!base) {
	68	char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
	69	int len = strlen(sha1_file_directory);
70	base = malloc(len + 60);
71	memcpy(base, sha1_file_directory, len);
72	memset(base+len, 0, 60);
73	base[len] = '/';
74	base[len+3] = '/';
75	name = base + len + 1;
76	}
77	for (i = 0; i < 20; i++) {
78	static char hex[] = "0123456789abcdef";
79	unsigned int val = sha1[i];
80	char pos = name + i2 + (i > 0);
81	*pos++ = hex[val >> 4];
82	*pos = hex[val & 0xf];
83	}
84	return base;
85	}
86
87	void * read_sha1_file(unsigned char sha1, char type, unsigned long *size)
88	{
89	z_stream stream;
90	char buffer[8192];
91	struct stat st;
19b2860c	92	int fd, ret, bytes;
e83c5163 LT	93	void map, buf;
	94	char *filename = sha1_file_name(sha1);
	95
	96	fd = open(filename, O_RDONLY);
	97	if (fd < 0) {
	98	perror(filename);
	99	return NULL;
	100	}
	101	if (fstat(fd, &st) < 0) {
	102	close(fd);
	103	return NULL;
	104	}
	105	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	106	close(fd);
	107	if (-1 == (int)(long)map)
	108	return NULL;
	109
	110	/* Get the data stream */
	111	memset(&stream, 0, sizeof(stream));
	112	stream.next_in = map;
	113	stream.avail_in = st.st_size;
	114	stream.next_out = buffer;
	115	stream.avail_out = sizeof(buffer);
	116
	117	inflateInit(&stream);
	118	ret = inflate(&stream, 0);
	119	if (sscanf(buffer, "%10s %lu", type, size) != 2)
	120	return NULL;
	121	bytes = strlen(buffer) + 1;
	122	buf = malloc(*size);
	123	if (!buf)
	124	return NULL;
	125
	126	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	127	bytes = stream.total_out - bytes;
	128	if (bytes < *size && ret == Z_OK) {
	129	stream.next_out = buf + bytes;
	130	stream.avail_out = *size - bytes;
	131	while (inflate(&stream, Z_FINISH) == Z_OK)
	132	/* nothing */;
	133	}
	134	inflateEnd(&stream);
	135	return buf;
	136	}
	137
	138	int write_sha1_file(char *buf, unsigned len)
	139	{
	140	int size;
	141	char *compressed;
	142	z_stream stream;
	143	unsigned char sha1[20];
	144	SHA_CTX c;
	145
	146	/* Set it up */
	147	memset(&stream, 0, sizeof(stream));
	148	deflateInit(&stream, Z_BEST_COMPRESSION);
	149	size = deflateBound(&stream, len);
	150	compressed = malloc(size);
	151
	152	/* Compress it */
	153	stream.next_in = buf;
	154	stream.avail_in = len;
	155	stream.next_out = compressed;
	156	stream.avail_out = size;
157	while (deflate(&stream, Z_FINISH) == Z_OK)
158	/* nothing */;
159	deflateEnd(&stream);
160	size = stream.total_out;
161
162	/* Sha1.. */
163	SHA1_Init(&c);
164	SHA1_Update(&c, compressed, size);
165	SHA1_Final(sha1, &c);
166
167	if (write_sha1_buffer(sha1, compressed, size) < 0)
168	return -1;
169	printf("%s\n", sha1_to_hex(sha1));
170	return 0;
171	}
172
173	int write_sha1_buffer(unsigned char sha1, void buf, unsigned int size)
174	{
175	char *filename = sha1_file_name(sha1);
19b2860c	176	int fd;
e83c5163 LT	177
	178	fd = open(filename, O_WRONLY \| O_CREAT \| O_EXCL, 0666);
	179	if (fd < 0)
	180	return (errno == EEXIST) ? 0 : -1;
	181	write(fd, buf, size);
	182	close(fd);
	183	return 0;
	184	}
	185
	186	static int error(const char * string)
	187	{
	188	fprintf(stderr, "error: %s\n", string);
	189	return -1;
	190	}
	191
	192	static int verify_hdr(struct cache_header *hdr, unsigned long size)
	193	{
	194	SHA_CTX c;
	195	unsigned char sha1[20];
	196
	197	if (hdr->signature != CACHE_SIGNATURE)
	198	return error("bad signature");
	199	if (hdr->version != 1)
	200	return error("bad version");
	201	SHA1_Init(&c);
	202	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	203	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	204	SHA1_Final(sha1, &c);
	205	if (memcmp(sha1, hdr->sha1, 20))
	206	return error("bad header sha1");
	207	return 0;
	208	}
	209
	210	int read_cache(void)
	211	{
	212	int fd, i;
	213	struct stat st;
	214	unsigned long size, offset;
	215	void *map;
	216	struct cache_header *hdr;
	217
	218	errno = EBUSY;
	219	if (active_cache)
	220	return error("more than one cachefile");
	221	errno = ENOENT;
	222	sha1_file_directory = getenv(DB_ENVIRONMENT);
	223	if (!sha1_file_directory)
	224	sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	225	if (access(sha1_file_directory, X_OK) < 0)
	226	return error("no access to SHA1 file directory");
	227	fd = open(".dircache/index", O_RDONLY);
	228	if (fd < 0)
	229	return (errno == ENOENT) ? 0 : error("open failed");
	230
19b2860c	231	size = 0; // avoid gcc warning
e83c5163 LT	232	map = (void *)-1;
	233	if (!fstat(fd, &st)) {
	234	map = NULL;
	235	size = st.st_size;
	236	errno = EINVAL;
	237	if (size > sizeof(struct cache_header))
	238	map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	239	}
	240	close(fd);
	241	if (-1 == (int)(long)map)
	242	return error("mmap failed");
	243
	244	hdr = map;
	245	if (verify_hdr(hdr, size) < 0)
	246	goto unmap;
	247
	248	active_nr = hdr->entries;
	249	active_alloc = alloc_nr(active_nr);
	250	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
	251
	252	offset = sizeof(*hdr);
	253	for (i = 0; i < hdr->entries; i++) {
	254	struct cache_entry *ce = map + offset;
	255	offset = offset + ce_size(ce);
	256	active_cache[i] = ce;
	257	}
	258	return active_nr;
	259
	260	unmap:
	261	munmap(map, size);
	262	errno = EINVAL;
	263	return error("verify header failed");
	264	}
	265