X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;ds=sidebyside;f=sha1_file.c;h=be991ed22acb0c84141474360f345d51ccc594be;hb=4b7f59af2a5b072a0a3950c956842e4d6223a167;hp=4304fe9bbc2b8e796e944fa7ddb2ea2791000adf;hpb=c182ec90d824168cfb70494bb920c0a2fb590d98;p=git.git

diff --git a/sha1_file.c b/sha1_file.c
index 4304fe9bb..aca741b79 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -13,6 +13,7 @@
 #include "commit.h"
 #include "tag.h"
 #include "tree.h"
+#include "refs.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -32,7 +33,7 @@ const unsigned char null_sha1[20];
 
 static unsigned int sha1_file_open_flag = O_NOATIME;
 
-signed char hexval_table[256] = {
+const signed char hexval_table[256] = {
 	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 00-07 */
 	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 08-0f */
 	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 10-17 */
@@ -192,7 +193,7 @@ char *sha1_pack_name(const unsigned char *sha1)
 		*buf++ = hex[val >> 4];
 		*buf++ = hex[val & 0xf];
 	}
-	
+
 	return base;
 }
 
@@ -217,7 +218,7 @@ char *sha1_pack_index_name(const unsigned char *sha1)
 		*buf++ = hex[val >> 4];
 		*buf++ = hex[val & 0xf];
 	}
-	
+
 	return base;
 }
 
@@ -351,10 +352,14 @@ static void read_info_alternates(const char * relative_base, int depth)
 	char *map;
 	size_t mapsz;
 	struct stat st;
-	char path[PATH_MAX];
+	const char alt_file_name[] = "info/alternates";
+	/* Given that relative_base is no longer than PATH_MAX,
+	   ensure that "path" has enough space to append "/", the
+	   file name, "info/alternates", and a trailing NUL.  */
+	char path[PATH_MAX + 1 + sizeof alt_file_name];
 	int fd;
 
-	sprintf(path, "%s/info/alternates", relative_base);
+	sprintf(path, "%s/%s", relative_base, alt_file_name);
 	fd = open(path, O_RDONLY);
 	if (fd < 0)
 		return;
@@ -375,11 +380,12 @@ void prepare_alt_odb(void)
 {
 	const char *alt;
 
+	if (alt_odb_tail)
+		return;
+
 	alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 	if (!alt) alt = "";
 
-	if (alt_odb_tail)
-		return;
 	alt_odb_tail = &alt_odb_list;
 	link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 
@@ -411,7 +417,7 @@ static size_t peak_pack_mapped;
 static size_t pack_mapped;
 struct packed_git *packed_git;
 
-void pack_report()
+void pack_report(void)
 {
 	fprintf(stderr,
 		"pack_report: getpagesize()            = %10" SZ_FMT "\n"
@@ -437,7 +443,7 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
 	void *idx_map;
 	struct pack_idx_header *hdr;
 	size_t idx_size;
-	uint32_t nr, i, *index;
+	uint32_t version, nr, i, *index;
 	int fd = open(path, O_RDONLY);
 	struct stat st;
 
@@ -455,21 +461,23 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
 	idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	close(fd);
 
-	/* a future index format would start with this, as older git
-	 * binaries would fail the non-monotonic index check below.
-	 * give a nicer warning to the user if we can.
-	 */
 	hdr = idx_map;
 	if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
-		munmap(idx_map, idx_size);
-		return error("index file %s is a newer version"
-			" and is not supported by this binary"
-			" (try upgrading GIT to a newer version)",
-			path);
-	}
+		version = ntohl(hdr->idx_version);
+		if (version < 2 || version > 2) {
+			munmap(idx_map, idx_size);
+			return error("index file %s is version %d"
+				     " and is not supported by this binary"
+				     " (try upgrading GIT to a newer version)",
+				     path, version);
+		}
+	} else
+		version = 1;
 
 	nr = 0;
 	index = idx_map;
+	if (version > 1)
+		index += 2;  /* skip index header */
 	for (i = 0; i < 256; i++) {
 		uint32_t n = ntohl(index[i]);
 		if (n < nr) {
@@ -479,24 +487,72 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
 		nr = n;
 	}
 
-	/*
-	 * Total size:
-	 *  - 256 index entries 4 bytes each
-	 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
-	 *  - 20-byte SHA1 of the packfile
-	 *  - 20-byte SHA1 file checksum
-	 */
-	if (idx_size != 4*256 + nr * 24 + 20 + 20) {
-		munmap(idx_map, idx_size);
-		return error("wrong index file size in %s", path);
+	if (version == 1) {
+		/*
+		 * Total size:
+		 *  - 256 index entries 4 bytes each
+		 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
+		 *  - 20-byte SHA1 of the packfile
+		 *  - 20-byte SHA1 file checksum
+		 */
+		if (idx_size != 4*256 + nr * 24 + 20 + 20) {
+			munmap(idx_map, idx_size);
+			return error("wrong index file size in %s", path);
+		}
+	} else if (version == 2) {
+		/*
+		 * Minimum size:
+		 *  - 8 bytes of header
+		 *  - 256 index entries 4 bytes each
+		 *  - 20-byte sha1 entry * nr
+		 *  - 4-byte crc entry * nr
+		 *  - 4-byte offset entry * nr
+		 *  - 20-byte SHA1 of the packfile
+		 *  - 20-byte SHA1 file checksum
+		 * And after the 4-byte offset table might be a
+		 * variable sized table containing 8-byte entries
+		 * for offsets larger than 2^31.
+		 */
+		unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
+		unsigned long max_size = min_size;
+		if (nr)
+			max_size += (nr - 1)*8;
+		if (idx_size < min_size || idx_size > max_size) {
+			munmap(idx_map, idx_size);
+			return error("wrong index file size in %s", path);
+		}
+		if (idx_size != min_size) {
+			/* make sure we can deal with large pack offsets */
+			off_t x = 0x7fffffffUL, y = 0xffffffffUL;
+			if (x > (x + 1) || y > (y + 1)) {
+				munmap(idx_map, idx_size);
+				return error("pack too large for current definition of off_t in %s", path);
+			}
+		}
 	}
 
-	p->index_version = 1;
+	p->index_version = version;
 	p->index_data = idx_map;
 	p->index_size = idx_size;
+	p->num_objects = nr;
 	return 0;
 }
 
+int open_pack_index(struct packed_git *p)
+{
+	char *idx_name;
+	int ret;
+
+	if (p->index_data)
+		return 0;
+
+	idx_name = xstrdup(p->pack_name);
+	strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
+	ret = check_packed_git_idx(idx_name, p);
+	free(idx_name);
+	return ret;
+}
+
 static void scan_windows(struct packed_git *p,
 	struct packed_git **lru_p,
 	struct pack_window **lru_w,
@@ -516,7 +572,7 @@ static void scan_windows(struct packed_git *p,
 	}
 }
 
-static int unuse_one_window(struct packed_git *current)
+static int unuse_one_window(struct packed_git *current, int keep_fd)
 {
 	struct packed_git *p, *lru_p = NULL;
 	struct pack_window *lru_w = NULL, *lru_l = NULL;
@@ -532,7 +588,7 @@ static int unuse_one_window(struct packed_git *current)
 			lru_l->next = lru_w->next;
 		else {
 			lru_p->windows = lru_w->next;
-			if (!lru_p->windows && lru_p != current) {
+			if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
 				close(lru_p->pack_fd);
 				lru_p->pack_fd = -1;
 			}
@@ -544,10 +600,10 @@ static int unuse_one_window(struct packed_git *current)
 	return 0;
 }
 
-void release_pack_memory(size_t need)
+void release_pack_memory(size_t need, int fd)
 {
 	size_t cur = pack_mapped;
-	while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
+	while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
 		; /* nothing */
 }
 
@@ -572,6 +628,9 @@ static int open_packed_git_1(struct packed_git *p)
 	unsigned char *idx_sha1;
 	long fd_flag;
 
+	if (!p->index_data && open_pack_index(p))
+		return error("packfile %s index unavailable", p->pack_name);
+
 	p->pack_fd = open(p->pack_name, O_RDONLY);
 	if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 		return -1;
@@ -605,11 +664,11 @@ static int open_packed_git_1(struct packed_git *p)
 			p->pack_name, ntohl(hdr.hdr_version));
 
 	/* Verify the pack matches its index. */
-	if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
+	if (p->num_objects != ntohl(hdr.hdr_entries))
 		return error("packfile %s claims to have %u objects"
-			" while index size indicates %u objects",
-			p->pack_name, ntohl(hdr.hdr_entries),
-			num_packed_objects(p));
+			     " while index indicates %u objects",
+			     p->pack_name, ntohl(hdr.hdr_entries),
+			     p->num_objects);
 	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 		return error("end of packfile %s is unavailable", p->pack_name);
 	if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
@@ -680,7 +739,7 @@ unsigned char* use_pack(struct packed_git *p,
 			win->len = (size_t)len;
 			pack_mapped += win->len;
 			while (packed_git_limit < pack_mapped
-				&& unuse_one_window(p))
+				&& unuse_one_window(p, p->pack_fd))
 				; /* nothing */
 			win->base = xmmap(NULL, win->len,
 				PROT_READ, MAP_PRIVATE,
@@ -724,8 +783,7 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 		return NULL;
 	memcpy(p->pack_name, path, path_len);
 	strcpy(p->pack_name + path_len, ".pack");
-	if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode) ||
-	    check_packed_git_idx(path, p)) {
+	if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 		free(p);
 		return NULL;
 	}
@@ -733,6 +791,10 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 	/* ok, it looks sane as far as we can check without
 	 * actually mapping the pack file.
 	 */
+	p->index_version = 0;
+	p->index_data = NULL;
+	p->index_size = 0;
+	p->num_objects = 0;
 	p->pack_size = st.st_size;
 	p->next = NULL;
 	p->windows = NULL;
@@ -778,7 +840,10 @@ void install_packed_git(struct packed_git *pack)
 
 static void prepare_packed_git_one(char *objdir, int local)
 {
-	char path[PATH_MAX];
+	/* Ensure that this buffer is large enough so that we can
+	   append "/pack/" without clobbering the stack even if
+	   strlen(objdir) were PATH_MAX.  */
+	char path[PATH_MAX + 1 + 4 + 1 + 1];
 	int len;
 	DIR *dir;
 	struct dirent *de;
@@ -800,6 +865,9 @@ static void prepare_packed_git_one(char *objdir, int local)
 		if (!has_extension(de->d_name, ".idx"))
 			continue;
 
+		if (len + namelen + 1 > sizeof(path))
+			continue;
+
 		/* Don't reopen a pack we already have. */
 		strcpy(path + len, de->d_name);
 		for (p = packed_git; p; p = p->next) {
@@ -904,7 +972,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long siz
 	return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
 	struct stat st;
 	void *map;
@@ -939,7 +1007,7 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 	return map;
 }
 
-int legacy_loose_object(unsigned char *map)
+static int legacy_loose_object(unsigned char *map)
 {
 	unsigned int word;
 
@@ -1001,6 +1069,14 @@ static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned lon
 		return inflate(stream, 0);
 	}
 
+
+	/*
+	 * There used to be a second loose object header format which
+	 * was meant to mimic the in-pack format, allowing for direct
+	 * copy of the object data.  This format turned up not to be
+	 * really worth it and we don't write it any longer.  But we
+	 * can still read it.
+	 */
 	used = unpack_object_header_gently(map, mapsize, &type, &size);
 	if (!used || !valid_loose_object_type[type])
 		return -1;
@@ -1076,7 +1152,7 @@ static int parse_sha1_header(const char *hdr, unsigned long *sizep)
 	unsigned long size;
 
 	/*
-	 * The type can be at most ten bytes (including the 
+	 * The type can be at most ten bytes (including the
 	 * terminating '\0' that we add), and is followed by
 	 * a space.
 	 */
@@ -1128,6 +1204,43 @@ static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type
 	return unpack_sha1_rest(&stream, hdr, *size, sha1);
 }
 
+unsigned long get_size_from_delta(struct packed_git *p,
+				  struct pack_window **w_curs,
+			          off_t curpos)
+{
+	const unsigned char *data;
+	unsigned char delta_head[20], *in;
+	z_stream stream;
+	int st;
+
+	memset(&stream, 0, sizeof(stream));
+	stream.next_out = delta_head;
+	stream.avail_out = sizeof(delta_head);
+
+	inflateInit(&stream);
+	do {
+		in = use_pack(p, w_curs, curpos, &stream.avail_in);
+		stream.next_in = in;
+		st = inflate(&stream, Z_FINISH);
+		curpos += stream.next_in - in;
+	} while ((st == Z_OK || st == Z_BUF_ERROR) &&
+		 stream.total_out < sizeof(delta_head));
+	inflateEnd(&stream);
+	if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
+		die("delta data unpack-initial failed");
+
+	/* Examine the initial part of the delta to figure out
+	 * the result size.
+	 */
+	data = delta_head;
+
+	/* ignore base size */
+	get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
+
+	/* Read the result size */
+	return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
+}
+
 static off_t get_delta_base(struct packed_git *p,
 				    struct pack_window **w_curs,
 				    off_t *curpos,
@@ -1149,7 +1262,7 @@ static off_t get_delta_base(struct packed_git *p,
 		base_offset = c & 127;
 		while (c & 128) {
 			base_offset += 1;
-			if (!base_offset || base_offset & ~(~0UL >> 7))
+			if (!base_offset || MSB(base_offset, 7))
 				die("offset value overflow for delta base object");
 			c = base_info[used++];
 			base_offset = (base_offset << 7) + (c & 127);
@@ -1191,40 +1304,8 @@ static int packed_delta_info(struct packed_git *p,
 	 * based on a base with a wrong size.  This saves tons of
 	 * inflate() calls.
 	 */
-	if (sizep) {
-		const unsigned char *data;
-		unsigned char delta_head[20], *in;
-		z_stream stream;
-		int st;
-
-		memset(&stream, 0, sizeof(stream));
-		stream.next_out = delta_head;
-		stream.avail_out = sizeof(delta_head);
-
-		inflateInit(&stream);
-		do {
-			in = use_pack(p, w_curs, curpos, &stream.avail_in);
-			stream.next_in = in;
-			st = inflate(&stream, Z_FINISH);
-			curpos += stream.next_in - in;
-		} while ((st == Z_OK || st == Z_BUF_ERROR)
-			&& stream.total_out < sizeof(delta_head));
-		inflateEnd(&stream);
-		if ((st != Z_STREAM_END) &&
-		    stream.total_out != sizeof(delta_head))
-			die("delta data unpack-initial failed");
-
-		/* Examine the initial part of the delta to figure out
-		 * the result size.
-		 */
-		data = delta_head;
-
-		/* ignore base size */
-		get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
-
-		/* Read the result size */
-		*sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
-	}
+	if (sizep)
+		*sizep = get_size_from_delta(p, w_curs, curpos);
 
 	return type;
 }
@@ -1526,37 +1607,71 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
 	return data;
 }
 
-uint32_t num_packed_objects(const struct packed_git *p)
+const unsigned char *nth_packed_object_sha1(struct packed_git *p,
+					    uint32_t n)
 {
-	/* See check_packed_git_idx() */
-	return (uint32_t)((p->index_size - 20 - 20 - 4*256) / 24);
+	const unsigned char *index = p->index_data;
+	if (!index) {
+		if (open_pack_index(p))
+			return NULL;
+		index = p->index_data;
+	}
+	if (n >= p->num_objects)
+		return NULL;
+	index += 4 * 256;
+	if (p->index_version == 1) {
+		return index + 24 * n + 4;
+	} else {
+		index += 8;
+		return index + 20 * n;
+	}
 }
 
-const unsigned char *nth_packed_object_sha1(const struct packed_git *p,
-					    uint32_t n)
+static off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
 {
 	const unsigned char *index = p->index_data;
 	index += 4 * 256;
-	if (num_packed_objects(p) <= n)
-		return NULL;
-	return index + 24 * n + 4;
+	if (p->index_version == 1) {
+		return ntohl(*((uint32_t *)(index + 24 * n)));
+	} else {
+		uint32_t off;
+		index += 8 + p->num_objects * (20 + 4);
+		off = ntohl(*((uint32_t *)(index + 4 * n)));
+		if (!(off & 0x80000000))
+			return off;
+		index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
+		return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
+				   ntohl(*((uint32_t *)(index + 4)));
+	}
 }
 
 off_t find_pack_entry_one(const unsigned char *sha1,
 				  struct packed_git *p)
 {
 	const uint32_t *level1_ofs = p->index_data;
-	int hi = ntohl(level1_ofs[*sha1]);
-	int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
 	const unsigned char *index = p->index_data;
+	unsigned hi, lo;
 
+	if (!index) {
+		if (open_pack_index(p))
+			return 0;
+		level1_ofs = p->index_data;
+		index = p->index_data;
+	}
+	if (p->index_version > 1) {
+		level1_ofs += 2;
+		index += 8;
+	}
 	index += 4 * 256;
+	hi = ntohl(level1_ofs[*sha1]);
+	lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
 
 	do {
-		int mi = (lo + hi) / 2;
-		int cmp = hashcmp(index + 24 * mi + 4, sha1);
+		unsigned mi = (lo + hi) / 2;
+		unsigned x = (p->index_version > 1) ? (mi * 20) : (mi * 24 + 4);
+		int cmp = hashcmp(index + x, sha1);
 		if (!cmp)
-			return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
+			return nth_packed_object_offset(p, mi);
 		if (cmp > 0)
 			hi = mi;
 		else
@@ -1585,20 +1700,25 @@ static int matches_pack_name(struct packed_git *p, const char *ig)
 
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
 {
+	static struct packed_git *last_found = (void *)1;
 	struct packed_git *p;
 	off_t offset;
 
 	prepare_packed_git();
+	if (!packed_git)
+		return 0;
+	p = (last_found == (void *)1) ? packed_git : last_found;
 
-	for (p = packed_git; p; p = p->next) {
+	do {
 		if (ignore_packed) {
 			const char **ig;
 			for (ig = ignore_packed; *ig; ig++)
 				if (!matches_pack_name(p, *ig))
 					break;
 			if (*ig)
-				continue;
+				goto next;
 		}
+
 		offset = find_pack_entry_one(sha1, p);
 		if (offset) {
 			/*
@@ -1611,18 +1731,27 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
 			 */
 			if (p->pack_fd == -1 && open_packed_git(p)) {
 				error("packfile %s cannot be accessed", p->pack_name);
-				continue;
+				goto next;
 			}
 			e->offset = offset;
 			e->p = p;
 			hashcpy(e->sha1, sha1);
+			last_found = p;
 			return 1;
 		}
-	}
+
+		next:
+		if (p == last_found)
+			p = packed_git;
+		else
+			p = p->next;
+		if (p == last_found)
+			p = p->next;
+	} while (p);
 	return 0;
 }
 
-struct packed_git *find_sha1_pack(const unsigned char *sha1, 
+struct packed_git *find_sha1_pack(const unsigned char *sha1,
 				  struct packed_git *packs)
 {
 	struct packed_git *p;
@@ -1901,40 +2030,6 @@ static int write_buffer(int fd, const void *buf, size_t len)
 	return 0;
 }
 
-static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
-{
-	int hdr_len;
-	unsigned char c;
-
-	c = (type << 4) | (len & 15);
-	len >>= 4;
-	hdr_len = 1;
-	while (len) {
-		*hdr++ = c | 0x80;
-		hdr_len++;
-		c = (len & 0x7f);
-		len >>= 7;
-	}
-	*hdr = c;
-	return hdr_len;
-}
-
-static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
-{
-	int obj_type, hdrlen;
-
-	if (use_legacy_headers) {
-		while (deflate(stream, 0) == Z_OK)
-			/* nothing */;
-		return;
-	}
-	obj_type = type_from_string(type);
-	hdrlen = write_binary_header(stream->next_out, obj_type, len);
-	stream->total_out = hdrlen;
-	stream->next_out += hdrlen;
-	stream->avail_out -= hdrlen;
-}
-
 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
                    unsigned char *sha1)
 {
@@ -2001,7 +2096,8 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
 	/* First header.. */
 	stream.next_in = (unsigned char *)hdr;
 	stream.avail_in = hdrlen;
-	setup_object_header(&stream, type, len);
+	while (deflate(&stream, 0) == Z_OK)
+		/* nothing */;
 
 	/* Then the data itself.. */
 	stream.next_in = buf;
@@ -2208,27 +2304,36 @@ int has_sha1_file(const unsigned char *sha1)
  *
  * returns 0 if anything went fine and -1 otherwise
  *
+ * The buffer is always NUL-terminated, not including it in returned size.
+ *
  * NOTE: both buf and size may change, but even when -1 is returned
  * you still have to free() it yourself.
  */
-int read_pipe(int fd, char** return_buf, unsigned long* return_size)
+int read_fd(int fd, char **return_buf, unsigned long *return_size)
 {
-	char* buf = *return_buf;
+	char *buf = *return_buf;
 	unsigned long size = *return_size;
-	int iret;
+	ssize_t iret;
 	unsigned long off = 0;
 
+	if (!buf || size <= 1) {
+		size = 1024;
+		buf = xrealloc(buf, size);
+	}
+
 	do {
-		iret = xread(fd, buf + off, size - off);
+		iret = xread(fd, buf + off, (size - 1) - off);
 		if (iret > 0) {
 			off += iret;
-			if (off == size) {
-				size *= 2;
+			if (off == size - 1) {
+				size = alloc_nr(size);
 				buf = xrealloc(buf, size);
 			}
 		}
 	} while (iret > 0);
 
+	buf[off] = '\0';
+
 	*return_buf = buf;
 	*return_size = off;
 
@@ -2243,7 +2348,7 @@ int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
 	char *buf = xmalloc(size);
 	int ret;
 
-	if (read_pipe(fd, &buf, &size)) {
+	if (read_fd(fd, &buf, &size)) {
 		free(buf);
 		return -1;
 	}
@@ -2277,10 +2382,9 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
 	 */
 	if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
 		unsigned long nsize = size;
-		char *nbuf = buf;
-		if (convert_to_git(path, &nbuf, &nsize)) {
-			if (size)
-				munmap(buf, size);
+		char *nbuf = convert_to_git(path, buf, &nsize);
+		if (nbuf) {
+			munmap(buf, size);
 			size = nsize;
 			buf = nbuf;
 			re_allocated = 1;
@@ -2332,6 +2436,8 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 				     path);
 		free(target);
 		break;
+	case S_IFDIR:
+		return resolve_gitlink_ref(path, "HEAD", sha1);
 	default:
 		return error("%s: unsupported file type", path);
 	}