1 files changed, 376 insertions, 337 deletions

diff --git a/sha1_file.c b/sha1_file.c
index 66a4e00fa..32e4664b1 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -14,6 +14,8 @@
 #include "tag.h"
 #include "tree.h"
 #include "refs.h"
+#include "pack-revindex.h"
+#include "sha1-lookup.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -33,8 +35,6 @@ static size_t sz_fmt(size_t s) { return s; }
 
 const unsigned char null_sha1[20];
 
-static unsigned int sha1_file_open_flag = O_NOATIME;
-
 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 */
@@ -83,14 +83,18 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
 	return 0;
 }
 
+static inline int offset_1st_component(const char *path)
+{
+	if (has_dos_drive_prefix(path))
+		return 2 + (path[2] == '/');
+	return *path == '/';
+}
+
 int safe_create_leading_directories(char *path)
 {
-	char *pos = path;
+	char *pos = path + offset_1st_component(path);
 	struct stat st;
 
-	if (is_absolute_path(path))
-		pos++;
-
 	while (pos) {
 		pos = strchr(pos, '/');
 		if (!pos)
@@ -116,7 +120,16 @@ int safe_create_leading_directories(char *path)
 	return 0;
 }
 
-char * sha1_to_hex(const unsigned char *sha1)
+int safe_create_leading_directories_const(const char *path)
+{
+	/* path points to cache entries, so xstrdup before messing with it */
+	char *buf = xstrdup(path);
+	int result = safe_create_leading_directories(buf);
+	free(buf);
+	return result;
+}
+
+char *sha1_to_hex(const unsigned char *sha1)
 {
 	static int bufno;
 	static char hexbuffer[4][50];
@@ -174,21 +187,23 @@ char *sha1_file_name(const unsigned char *sha1)
 	return base;
 }
 
-char *sha1_pack_name(const unsigned char *sha1)
+static char *sha1_get_pack_name(const unsigned char *sha1,
+				char **name, char **base, const char *which)
 {
 	static const char hex[] = "0123456789abcdef";
-	static char *name, *base, *buf;
+	char *buf;
 	int i;
 
-	if (!base) {
+	if (!*base) {
 		const char *sha1_file_directory = get_object_directory();
 		int len = strlen(sha1_file_directory);
-		base = xmalloc(len + 60);
-		sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
-		name = base + len + 11;
+		*base = xmalloc(len + 60);
+		sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
+			sha1_file_directory, which);
+		*name = *base + len + 11;
 	}
 
-	buf = name;
+	buf = *name;
 
 	for (i = 0; i < 20; i++) {
 		unsigned int val = *sha1++;
@@ -196,32 +211,21 @@ char *sha1_pack_name(const unsigned char *sha1)
 		*buf++ = hex[val & 0xf];
 	}
 
-	return base;
+	return *base;
 }
 
-char *sha1_pack_index_name(const unsigned char *sha1)
+char *sha1_pack_name(const unsigned char *sha1)
 {
-	static const char hex[] = "0123456789abcdef";
-	static char *name, *base, *buf;
-	int i;
-
-	if (!base) {
-		const char *sha1_file_directory = get_object_directory();
-		int len = strlen(sha1_file_directory);
-		base = xmalloc(len + 60);
-		sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
-		name = base + len + 11;
-	}
+	static char *name, *base;
 
-	buf = name;
+	return sha1_get_pack_name(sha1, &name, &base, "pack");
+}
 
-	for (i = 0; i < 20; i++) {
-		unsigned int val = *sha1++;
-		*buf++ = hex[val >> 4];
-		*buf++ = hex[val & 0xf];
-	}
+char *sha1_pack_index_name(const unsigned char *sha1)
+{
+	static char *name, *base;
 
-	return base;
+	return sha1_get_pack_name(sha1, &name, &base, "idx");
 }
 
 struct alternate_object_database *alt_odb_list;
@@ -378,6 +382,18 @@ static void read_info_alternates(const char * relative_base, int depth)
 	munmap(map, mapsz);
 }
 
+void add_to_alternates_file(const char *reference)
+{
+	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+	int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), 1);
+	char *alt = mkpath("%s/objects\n", reference);
+	write_or_die(fd, alt, strlen(alt));
+	if (commit_lock_file(lock))
+		die("could not close alternates file");
+	if (alt_odb_tail)
+		link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
+}
+
 void prepare_alt_odb(void)
 {
 	const char *alt;
@@ -389,26 +405,26 @@ void prepare_alt_odb(void)
 	if (!alt) alt = "";
 
 	alt_odb_tail = &alt_odb_list;
-	link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
+	link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0);
 
 	read_info_alternates(get_object_directory(), 0);
 }
 
-static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
+static int has_loose_object(const unsigned char *sha1)
 {
 	char *name = sha1_file_name(sha1);
 	struct alternate_object_database *alt;
 
-	if (!stat(name, st))
-		return name;
+	if (!access(name, F_OK))
+		return 1;
 	prepare_alt_odb();
 	for (alt = alt_odb_list; alt; alt = alt->next) {
 		name = alt->name;
 		fill_sha1_path(name, sha1);
-		if (!stat(alt->base, st))
-			return alt->base;
+		if (!access(alt->base, F_OK))
+			return 1;
 	}
-	return NULL;
+	return 0;
 }
 
 static unsigned int pack_used_ctr;
@@ -468,7 +484,7 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
 		version = ntohl(hdr->idx_version);
 		if (version < 2 || version > 2) {
 			munmap(idx_map, idx_size);
-			return error("index file %s is version %d"
+			return error("index file %s is version %"PRIu32
 				     " and is not supported by this binary"
 				     " (try upgrading GIT to a newer version)",
 				     path, version);
@@ -679,14 +695,14 @@ static int open_packed_git_1(struct packed_git *p)
 	if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 		return error("file %s is not a GIT packfile", p->pack_name);
 	if (!pack_version_ok(hdr.hdr_version))
-		return error("packfile %s is version %u and not supported"
-			" (try upgrading GIT to a newer version)",
+		return error("packfile %s is version %"PRIu32" and not"
+			" supported (try upgrading GIT to a newer version)",
 			p->pack_name, ntohl(hdr.hdr_version));
 
 	/* Verify the pack matches its index. */
 	if (p->num_objects != ntohl(hdr.hdr_entries))
-		return error("packfile %s claims to have %u objects"
-			     " while index indicates %u objects",
+		return error("packfile %s claims to have %"PRIu32" objects"
+			     " while index indicates %"PRIu32" objects",
 			     p->pack_name, ntohl(hdr.hdr_entries),
 			     p->num_objects);
 	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
@@ -789,18 +805,28 @@ unsigned char* use_pack(struct packed_git *p,
 	return win->base + offset;
 }
 
+static struct packed_git *alloc_packed_git(int extra)
+{
+	struct packed_git *p = xmalloc(sizeof(*p) + extra);
+	memset(p, 0, sizeof(*p));
+	p->pack_fd = -1;
+	return p;
+}
+
 struct packed_git *add_packed_git(const char *path, int path_len, int local)
 {
 	struct stat st;
-	struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2);
+	struct packed_git *p = alloc_packed_git(path_len + 2);
 
 	/*
 	 * Make sure a corresponding .pack file exists and that
 	 * the index looks sane.
 	 */
 	path_len -= strlen(".idx");
-	if (path_len < 1)
+	if (path_len < 1) {
+		free(p);
 		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)) {
@@ -811,14 +837,7 @@ 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;
-	p->pack_fd = -1;
 	p->pack_local = local;
 	p->mtime = st.st_mtime;
 	if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
@@ -828,27 +847,17 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 
 struct packed_git *parse_pack_index(unsigned char *sha1)
 {
-	char *path = sha1_pack_index_name(sha1);
-	return parse_pack_index_file(sha1, path);
-}
-
-struct packed_git *parse_pack_index_file(const unsigned char *sha1,
-					 const char *idx_path)
-{
+	const char *idx_path = sha1_pack_index_name(sha1);
 	const char *path = sha1_pack_name(sha1);
-	struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
+	struct packed_git *p = alloc_packed_git(strlen(path) + 1);
 
+	strcpy(p->pack_name, path);
+	hashcpy(p->sha1, sha1);
 	if (check_packed_git_idx(idx_path, p)) {
 		free(p);
 		return NULL;
 	}
 
-	strcpy(p->pack_name, path);
-	p->pack_size = 0;
-	p->next = NULL;
-	p->windows = NULL;
-	p->pack_fd = -1;
-	hashcpy(p->sha1, sha1);
 	return p;
 }
 
@@ -985,6 +994,30 @@ void reprepare_packed_git(void)
 	prepare_packed_git();
 }
 
+static void mark_bad_packed_object(struct packed_git *p,
+				   const unsigned char *sha1)
+{
+	unsigned i;
+	for (i = 0; i < p->num_bad_objects; i++)
+		if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+			return;
+	p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
+	hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
+	p->num_bad_objects++;
+}
+
+static int has_packed_and_bad(const unsigned char *sha1)
+{
+	struct packed_git *p;
+	unsigned i;
+
+	for (p = packed_git; p; p = p->next)
+		for (i = 0; i < p->num_bad_objects; i++)
+			if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+				return 1;
+	return 0;
+}
+
 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 {
 	unsigned char real_sha1[20];
@@ -992,38 +1025,58 @@ int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long siz
 	return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
+static int git_open_noatime(const char *name)
+{
+	static int sha1_file_open_flag = O_NOATIME;
+	int fd = open(name, O_RDONLY | sha1_file_open_flag);
+
+	/* Might the failure be due to O_NOATIME? */
+	if (fd < 0 && errno != ENOENT && sha1_file_open_flag) {
+		fd = open(name, O_RDONLY);
+		if (fd >= 0)
+			sha1_file_open_flag = 0;
+	}
+	return fd;
+}
+
+static int open_sha1_file(const unsigned char *sha1)
+{
+	int fd;
+	char *name = sha1_file_name(sha1);
+	struct alternate_object_database *alt;
+
+	fd = git_open_noatime(name);
+	if (fd >= 0)
+		return fd;
+
+	prepare_alt_odb();
+	errno = ENOENT;
+	for (alt = alt_odb_list; alt; alt = alt->next) {
+		name = alt->name;
+		fill_sha1_path(name, sha1);
+		fd = git_open_noatime(alt->base);
+		if (fd >= 0)
+			return fd;
+	}
+	return -1;
+}
+
 static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
-	struct stat st;
 	void *map;
 	int fd;
-	char *filename = find_sha1_file(sha1, &st);
 
-	if (!filename) {
-		return NULL;
-	}
+	fd = open_sha1_file(sha1);
+	map = NULL;
+	if (fd >= 0) {
+		struct stat st;
 
-	fd = open(filename, O_RDONLY | sha1_file_open_flag);
-	if (fd < 0) {
-		/* See if it works without O_NOATIME */
-		switch (sha1_file_open_flag) {
-		default:
-			fd = open(filename, O_RDONLY);
-			if (fd >= 0)
-				break;
-		/* Fallthrough */
-		case 0:
-			return NULL;
+		if (!fstat(fd, &st)) {
+			*size = xsize_t(st.st_size);
+			map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 		}
-
-		/* If it failed once, it will probably fail again.
-		 * Stop using O_NOATIME
-		 */
-		sha1_file_open_flag = 0;
+		close(fd);
 	}
-	*size = xsize_t(st.st_size);
-	map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
-	close(fd);
 	return map;
 }
 
@@ -1283,20 +1336,17 @@ static off_t get_delta_base(struct packed_git *p,
 		while (c & 128) {
 			base_offset += 1;
 			if (!base_offset || MSB(base_offset, 7))
-				die("offset value overflow for delta base object");
+				return 0;  /* overflow */
 			c = base_info[used++];
 			base_offset = (base_offset << 7) + (c & 127);
 		}
 		base_offset = delta_obj_offset - base_offset;
 		if (base_offset >= delta_obj_offset)
-			die("delta base offset out of bound");
+			return 0;  /* out of bound */
 		*curpos += used;
 	} else if (type == OBJ_REF_DELTA) {
 		/* The base entry _must_ be in the same pack */
 		base_offset = find_pack_entry_one(base_info, p);
-		if (!base_offset)
-			die("failed to find delta-pack base object %s",
-				sha1_to_hex(base_info));
 		*curpos += 20;
 	} else
 		die("I am totally screwed");
@@ -1367,11 +1417,15 @@ const char *packed_object_info_detail(struct packed_git *p,
 	unsigned long dummy;
 	unsigned char *next_sha1;
 	enum object_type type;
+	struct revindex_entry *revidx;
 
 	*delta_chain_length = 0;
 	curpos = obj_offset;
 	type = unpack_object_header(p, &w_curs, &curpos, size);
 
+	revidx = find_pack_revindex(p, obj_offset);
+	*store_size = revidx[1].offset - obj_offset;
+
 	for (;;) {
 		switch (type) {
 		default:
@@ -1381,14 +1435,16 @@ const char *packed_object_info_detail(struct packed_git *p,
 		case OBJ_TREE:
 		case OBJ_BLOB:
 		case OBJ_TAG:
-			*store_size = 0; /* notyet */
 			unuse_pack(&w_curs);
 			return typename(type);
 		case OBJ_OFS_DELTA:
 			obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
+			if (!obj_offset)
+				die("pack %s contains bad delta base reference of type %s",
+				    p->pack_name, typename(type));
 			if (*delta_chain_length == 0) {
-				/* TODO: find base_sha1 as pointed by curpos */
-				hashclr(base_sha1);
+				revidx = find_pack_revindex(p, obj_offset);
+				hashcpy(base_sha1, nth_packed_object_sha1(p, revidx->nr));
 			}
 			break;
 		case OBJ_REF_DELTA:
@@ -1580,17 +1636,42 @@ static void *unpack_delta_entry(struct packed_git *p,
 	off_t base_offset;
 
 	base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
+	if (!base_offset) {
+		error("failed to validate delta base reference "
+		      "at offset %"PRIuMAX" from %s",
+		      (uintmax_t)curpos, p->pack_name);
+		return NULL;
+	}
+	unuse_pack(w_curs);
 	base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
-	if (!base)
-		die("failed to read delta base object"
-		    " at %"PRIuMAX" from %s",
-		    (uintmax_t)base_offset, p->pack_name);
+	if (!base) {
+		/*
+		 * We're probably in deep shit, but let's try to fetch
+		 * the required base anyway from another pack or loose.
+		 * This is costly but should happen only in the presence
+		 * of a corrupted pack, and is better than failing outright.
+		 */
+		struct revindex_entry *revidx = find_pack_revindex(p, base_offset);
+		const unsigned char *base_sha1 =
+					nth_packed_object_sha1(p, revidx->nr);
+		error("failed to read delta base object %s"
+		      " at offset %"PRIuMAX" from %s",
+		      sha1_to_hex(base_sha1), (uintmax_t)base_offset,
+		      p->pack_name);
+		mark_bad_packed_object(p, base_sha1);
+		base = read_object(base_sha1, type, &base_size);
+		if (!base)
+			return NULL;
+	}
 
 	delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
-	if (!delta_data)
-		die("failed to unpack compressed delta"
-		    " at %"PRIuMAX" from %s",
-		    (uintmax_t)curpos, p->pack_name);
+	if (!delta_data) {
+		error("failed to unpack compressed delta "
+		      "at offset %"PRIuMAX" from %s",
+		      (uintmax_t)curpos, p->pack_name);
+		free(base);
+		return NULL;
+	}
 	result = patch_delta(base, base_size,
 			     delta_data, delta_size,
 			     sizep);
@@ -1622,7 +1703,9 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
 		data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
 		break;
 	default:
-		die("unknown object type %i in %s", *type, p->pack_name);
+		data = NULL;
+		error("unknown object type %i at offset %"PRIuMAX" in %s",
+		      *type, (uintmax_t)obj_offset, p->pack_name);
 	}
 	unuse_pack(&w_curs);
 	return data;
@@ -1648,7 +1731,7 @@ const unsigned char *nth_packed_object_sha1(struct packed_git *p,
 	}
 }
 
-static off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
+off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
 {
 	const unsigned char *index = p->index_data;
 	index += 4 * 256;
@@ -1671,7 +1754,12 @@ off_t find_pack_entry_one(const unsigned char *sha1,
 {
 	const uint32_t *level1_ofs = p->index_data;
 	const unsigned char *index = p->index_data;
-	unsigned hi, lo;
+	unsigned hi, lo, stride;
+	static int use_lookup = -1;
+	static int debug_lookup = -1;
+
+	if (debug_lookup < 0)
+		debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
 
 	if (!index) {
 		if (open_pack_index(p))
@@ -1686,11 +1774,34 @@ off_t find_pack_entry_one(const unsigned char *sha1,
 	index += 4 * 256;
 	hi = ntohl(level1_ofs[*sha1]);
 	lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
+	if (p->index_version > 1) {
+		stride = 20;
+	} else {
+		stride = 24;
+		index += 4;
+	}
+
+	if (debug_lookup)
+		printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
+		       sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
+
+	if (use_lookup < 0)
+		use_lookup = !!getenv("GIT_USE_LOOKUP");
+	if (use_lookup) {
+		int pos = sha1_entry_pos(index, stride, 0,
+					 lo, hi, p->num_objects, sha1);
+		if (pos < 0)
+			return 0;
+		return nth_packed_object_offset(p, pos);
+	}
 
 	do {
 		unsigned mi = (lo + hi) / 2;
-		unsigned x = (p->index_version > 1) ? (mi * 20) : (mi * 24 + 4);
-		int cmp = hashcmp(index + x, sha1);
+		int cmp = hashcmp(index + mi * stride, sha1);
+
+		if (debug_lookup)
+			printf("lo %u hi %u rg %u mi %u\n",
+			       lo, hi, hi - lo, mi);
 		if (!cmp)
 			return nth_packed_object_offset(p, mi);
 		if (cmp > 0)
@@ -1740,6 +1851,13 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
 				goto next;
 		}
 
+		if (p->num_bad_objects) {
+			unsigned i;
+			for (i = 0; i < p->num_bad_objects; i++)
+				if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+					goto next;
+		}
+
 		offset = find_pack_entry_one(sha1, p);
 		if (offset) {
 			/*
@@ -1811,11 +1929,18 @@ static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *size
 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
 	struct pack_entry e;
+	int status;
 
 	if (!find_pack_entry(sha1, &e, NULL)) {
+		/* Most likely it's a loose object. */
+		status = sha1_loose_object_info(sha1, sizep);
+		if (status >= 0)
+			return status;
+
+		/* Not a loose object; someone else may have just packed it. */
 		reprepare_packed_git();
 		if (!find_pack_entry(sha1, &e, NULL))
-			return sha1_loose_object_info(sha1, sizep);
+			return status;
 	}
 	return packed_object_info(e.p, e.offset, sizep);
 }
@@ -1824,11 +1949,24 @@ static void *read_packed_sha1(const unsigned char *sha1,
 			      enum object_type *type, unsigned long *size)
 {
 	struct pack_entry e;
+	void *data;
 
 	if (!find_pack_entry(sha1, &e, NULL))
 		return NULL;
-	else
-		return cache_or_unpack_entry(e.p, e.offset, size, type, 1);
+	data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
+	if (!data) {
+		/*
+		 * We're probably in deep shit, but let's try to fetch
+		 * the required object anyway from another pack or loose.
+		 * This should happen only in the presence of a corrupted
+		 * pack, and is better than failing outright.
+		 */
+		error("failed to read object %s at offset %"PRIuMAX" from %s",
+		      sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
+		mark_bad_packed_object(e.p, sha1);
+		data = read_object(sha1, type, size);
+	}
+	return data;
 }
 
 /*
@@ -1845,6 +1983,15 @@ static struct cached_object {
 } *cached_objects;
 static int cached_object_nr, cached_object_alloc;
 
+static struct cached_object empty_tree = {
+	/* empty tree sha1: 4b825dc642cb6eb9a060e54bf8d69288fbee4904 */
+	"\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60"
+	"\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04",
+	OBJ_TREE,
+	"",
+	0
+};
+
 static struct cached_object *find_cached_object(const unsigned char *sha1)
 {
 	int i;
@@ -1854,6 +2001,8 @@ static struct cached_object *find_cached_object(const unsigned char *sha1)
 		if (!hashcmp(co->sha1, sha1))
 			return co;
 	}
+	if (!hashcmp(sha1, empty_tree.sha1))
+		return &empty_tree;
 	return NULL;
 }
 
@@ -1880,8 +2029,8 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
 	return 0;
 }
 
-void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
-		     unsigned long *size)
+void *read_object(const unsigned char *sha1, enum object_type *type,
+		  unsigned long *size)
 {
 	unsigned long mapsize;
 	void *map, *buf;
@@ -1907,6 +2056,16 @@ void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
 	return read_packed_sha1(sha1, type, size);
 }
 
+void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
+		     unsigned long *size)
+{
+	void *data = read_object(sha1, type, size);
+	/* legacy behavior is to die on corrupted objects */
+	if (!data && (has_loose_object(sha1) || has_packed_and_bad(sha1)))
+		die("object %s is corrupted", sha1_to_hex(sha1));
+	return data;
+}
+
 void *read_object_with_reference(const unsigned char *sha1,
 				 const char *required_type_name,
 				 unsigned long *size,
@@ -1943,7 +2102,8 @@ void *read_object_with_reference(const unsigned char *sha1,
 		}
 		ref_length = strlen(ref_type);
 
-		if (memcmp(buffer, ref_type, ref_length) ||
+		if (ref_length + 40 > isize ||
+		    memcmp(buffer, ref_type, ref_length) ||
 		    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
 			free(buffer);
 			return NULL;
@@ -1971,48 +2131,11 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
 }
 
 /*
- * Link the tempfile to the final place, possibly creating the
- * last directory level as you do so.
- *
- * Returns the errno on failure, 0 on success.
- */
-static int link_temp_to_file(const char *tmpfile, const char *filename)
-{
-	int ret;
-	char *dir;
-
-	if (!link(tmpfile, filename))
-		return 0;
-
-	/*
-	 * Try to mkdir the last path component if that failed.
-	 *
-	 * Re-try the "link()" regardless of whether the mkdir
-	 * succeeds, since a race might mean that somebody
-	 * else succeeded.
-	 */
-	ret = errno;
-	dir = strrchr(filename, '/');
-	if (dir) {
-		*dir = 0;
-		if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
-			*dir = '/';
-			return -2;
-		}
-		*dir = '/';
-		if (!link(tmpfile, filename))
-			return 0;
-		ret = errno;
-	}
-	return ret;
-}
-
-/*
  * Move the just written object into its final resting place
  */
 int move_temp_to_file(const char *tmpfile, const char *filename)
 {
-	int ret = link_temp_to_file(tmpfile, filename);
+	int ret = link(tmpfile, filename);
 
 	/*
 	 * Coda hack - coda doesn't like cross-directory links,
@@ -2057,43 +2180,68 @@ int hash_sha1_file(const void *buf, unsigned long len, const char *type,
 	return 0;
 }
 
-int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
+/* Finalize a file on disk, and close it. */
+static void close_sha1_file(int fd)
 {
-	int size, ret;
-	unsigned char *compressed;
-	z_stream stream;
-	unsigned char sha1[20];
-	char *filename;
-	static char tmpfile[PATH_MAX];
-	char hdr[32];
-	int fd, hdrlen;
+	if (fsync_object_files)
+		fsync_or_die(fd, "sha1 file");
+	fchmod(fd, 0444);
+	if (close(fd) != 0)
+		die("unable to write sha1 file");
+}
 
-	/* Normally if we have it in the pack then we do not bother writing
-	 * it out into .git/objects/??/?{38} file.
-	 */
-	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
-	filename = sha1_file_name(sha1);
-	if (returnsha1)
-		hashcpy(returnsha1, sha1);
-	if (has_sha1_file(sha1))
-		return 0;
-	fd = open(filename, O_RDONLY);
-	if (fd >= 0) {
-		/*
-		 * FIXME!!! We might do collision checking here, but we'd
-		 * need to uncompress the old file and check it. Later.
-		 */
-		close(fd);
+/* Size of directory component, including the ending '/' */
+static inline int directory_size(const char *filename)
+{
+	const char *s = strrchr(filename, '/');
+	if (!s)
 		return 0;
+	return s - filename + 1;
+}
+
+/*
+ * This creates a temporary file in the same directory as the final
+ * 'filename'
+ *
+ * We want to avoid cross-directory filename renames, because those
+ * can have problems on various filesystems (FAT, NFS, Coda).
+ */
+static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
+{
+	int fd, dirlen = directory_size(filename);
+
+	if (dirlen + 20 > bufsiz) {
+		errno = ENAMETOOLONG;
+		return -1;
 	}
+	memcpy(buffer, filename, dirlen);
+	strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
+	fd = mkstemp(buffer);
+	if (fd < 0 && dirlen) {
+		/* Make sure the directory exists */
+		memcpy(buffer, filename, dirlen);
+		buffer[dirlen-1] = 0;
+		if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
+			return -1;
 
-	if (errno != ENOENT) {
-		return error("sha1 file %s: %s\n", filename, strerror(errno));
+		/* Try again */
+		strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
+		fd = mkstemp(buffer);
 	}
+	return fd;
+}
 
-	snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
+static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
+			      void *buf, unsigned long len, time_t mtime)
+{
+	int fd, size, ret;
+	unsigned char *compressed;
+	z_stream stream;
+	char *filename;
+	static char tmpfile[PATH_MAX];
 
-	fd = mkstemp(tmpfile);
+	filename = sha1_file_name(sha1);
+	fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
 	if (fd < 0) {
 		if (errno == EPERM)
 			return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
@@ -2132,156 +2280,53 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
 
 	if (write_buffer(fd, compressed, size) < 0)
 		die("unable to write sha1 file");
-	fchmod(fd, 0444);
-	if (close(fd))
-		die("unable to write sha1 file");
+	close_sha1_file(fd);
 	free(compressed);
 
+	if (mtime) {
+		struct utimbuf utb;
+		utb.actime = mtime;
+		utb.modtime = mtime;
+		if (utime(tmpfile, &utb) < 0)
+			warning("failed utime() on %s: %s",
+				tmpfile, strerror(errno));
+	}
+
 	return move_temp_to_file(tmpfile, filename);
 }
 
-/*
- * We need to unpack and recompress the object for writing
- * it out to a different file.
- */
-static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
+int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
-	size_t size;
-	z_stream stream;
-	unsigned char *unpacked;
-	unsigned long len;
-	enum object_type type;
+	unsigned char sha1[20];
 	char hdr[32];
 	int hdrlen;
-	void *buf;
 
-	/* need to unpack and recompress it by itself */
-	unpacked = read_packed_sha1(sha1, &type, &len);
-	if (!unpacked)
-		error("cannot read sha1_file for %s", sha1_to_hex(sha1));
-
-	hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
-
-	/* Set it up */
-	memset(&stream, 0, sizeof(stream));
-	deflateInit(&stream, zlib_compression_level);
-	size = deflateBound(&stream, len + hdrlen);
-	buf = xmalloc(size);
-
-	/* Compress it */
-	stream.next_out = buf;
-	stream.avail_out = size;
-
-	/* First header.. */
-	stream.next_in = (void *)hdr;
-	stream.avail_in = hdrlen;
-	while (deflate(&stream, 0) == Z_OK)
-		/* nothing */;
-
-	/* Then the data itself.. */
-	stream.next_in = unpacked;
-	stream.avail_in = len;
-	while (deflate(&stream, Z_FINISH) == Z_OK)
-		/* nothing */;
-	deflateEnd(&stream);
-	free(unpacked);
-
-	*objsize = stream.total_out;
-	return buf;
-}
-
-int write_sha1_to_fd(int fd, const unsigned char *sha1)
-{
-	int retval;
-	unsigned long objsize;
-	void *buf = map_sha1_file(sha1, &objsize);
-
-	if (buf) {
-		retval = write_buffer(fd, buf, objsize);
-		munmap(buf, objsize);
-		return retval;
-	}
-
-	buf = repack_object(sha1, &objsize);
-	retval = write_buffer(fd, buf, objsize);
-	free(buf);
-	return retval;
+	/* Normally if we have it in the pack then we do not bother writing
+	 * it out into .git/objects/??/?{38} file.
+	 */
+	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
+	if (returnsha1)
+		hashcpy(returnsha1, sha1);
+	if (has_sha1_file(sha1))
+		return 0;
+	return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
 }
 
-int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
-		       size_t bufsize, size_t *bufposn)
+int force_object_loose(const unsigned char *sha1, time_t mtime)
 {
-	char tmpfile[PATH_MAX];
-	int local;
-	z_stream stream;
-	unsigned char real_sha1[20];
-	unsigned char discard[4096];
-	int ret;
-	SHA_CTX c;
-
-	snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
-
-	local = mkstemp(tmpfile);
-	if (local < 0) {
-		if (errno == EPERM)
-			return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
-		else
-			return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
-	}
-
-	memset(&stream, 0, sizeof(stream));
-
-	inflateInit(&stream);
-
-	SHA1_Init(&c);
-
-	do {
-		ssize_t size;
-		if (*bufposn) {
-			stream.avail_in = *bufposn;
-			stream.next_in = (unsigned char *) buffer;
-			do {
-				stream.next_out = discard;
-				stream.avail_out = sizeof(discard);
-				ret = inflate(&stream, Z_SYNC_FLUSH);
-				SHA1_Update(&c, discard, sizeof(discard) -
-					    stream.avail_out);
-			} while (stream.avail_in && ret == Z_OK);
-			if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
-				die("unable to write sha1 file");
-			memmove(buffer, buffer + *bufposn - stream.avail_in,
-				stream.avail_in);
-			*bufposn = stream.avail_in;
-			if (ret != Z_OK)
-				break;
-		}
-		size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
-		if (size <= 0) {
-			close(local);
-			unlink(tmpfile);
-			if (!size)
-				return error("Connection closed?");
-			perror("Reading from connection");
-			return -1;
-		}
-		*bufposn += size;
-	} while (1);
-	inflateEnd(&stream);
-
-	fchmod(local, 0444);
-	if (close(local) != 0)
-		die("unable to write sha1 file");
-	SHA1_Final(real_sha1, &c);
-	if (ret != Z_STREAM_END) {
-		unlink(tmpfile);
-		return error("File %s corrupted", sha1_to_hex(sha1));
-	}
-	if (hashcmp(sha1, real_sha1)) {
-		unlink(tmpfile);
-		return error("File %s has bad hash", sha1_to_hex(sha1));
-	}
+	void *buf;
+	unsigned long len;
+	enum object_type type;
+	char hdr[32];
+	int hdrlen;
 
-	return move_temp_to_file(tmpfile, sha1_file_name(sha1));
+	if (has_loose_object(sha1))
+		return 0;
+	buf = read_packed_sha1(sha1, &type, &len);
+	if (!buf)
+		return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+	hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
+	return write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
 }
 
 int has_pack_index(const unsigned char *sha1)
@@ -2308,12 +2353,11 @@ int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
 
 int has_sha1_file(const unsigned char *sha1)
 {
-	struct stat st;
 	struct pack_entry e;
 
 	if (find_pack_entry(sha1, &e, NULL))
 		return 1;
-	return find_sha1_file(sha1, &st) ? 1 : 0;
+	return has_loose_object(sha1);
 }
 
 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
@@ -2358,7 +2402,8 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
 	if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
 		struct strbuf nbuf;
 		strbuf_init(&nbuf, 0);
-		if (convert_to_git(path, buf, size, &nbuf)) {
+		if (convert_to_git(path, buf, size, &nbuf,
+		                   write_object ? safe_crlf : 0)) {
 			munmap(buf, size);
 			buf = strbuf_detach(&nbuf, &size);
 			re_allocated = 1;
@@ -2420,16 +2465,10 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 
 int read_pack_header(int fd, struct pack_header *header)
 {
-	char *c = (char*)header;
-	ssize_t remaining = sizeof(struct pack_header);
-	do {
-		ssize_t r = xread(fd, c, remaining);
-		if (r <= 0)
-			/* "eof before pack header was fully read" */
-			return PH_ERROR_EOF;
-		remaining -= r;
-		c += r;
-	} while (remaining > 0);
+	if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
+		/* "eof before pack header was fully read" */
+		return PH_ERROR_EOF;
+
 	if (header->hdr_signature != htonl(PACK_SIGNATURE))
 		/* "protocol error (pack signature mismatch detected)" */
 		return PH_ERROR_PACK_SIGNATURE;