X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=sha1_file.c;h=2c870314d525ba0666470d53cf7901a2bac9e3c0;hb=7943b3a94f0f862dc9d7dcec6b5639ae5bf027bd;hp=53e25f278c6193860431f63a3c9de97f4e347f27;hpb=ccd14e569dcfe1a83b33f84fad8cfed68676ef5d;p=git.git

diff --git a/sha1_file.c b/sha1_file.c
index 53e25f278..2c870314d 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -407,7 +407,6 @@ static unsigned int peak_pack_open_windows;
 static unsigned int pack_open_windows;
 static size_t peak_pack_mapped;
 static size_t pack_mapped;
-static size_t page_size;
 struct packed_git *packed_git;
 
 void pack_report()
@@ -416,7 +415,7 @@ void pack_report()
 		"pack_report: getpagesize()            = %10" SZ_FMT "\n"
 		"pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 		"pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
-		page_size,
+		(size_t) getpagesize(),
 		packed_git_window_size,
 		packed_git_limit);
 	fprintf(stderr,
@@ -435,7 +434,7 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 				void **idx_map_)
 {
 	void *idx_map;
-	unsigned int *index;
+	uint32_t *index;
 	unsigned long idx_size;
 	int nr, i;
 	int fd = open(path, O_RDONLY);
@@ -456,12 +455,23 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 
 	/* check index map */
 	if (idx_size < 4*256 + 20 + 20)
-		return error("index file too small");
+		return error("index file %s is too small", path);
+
+	/* 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.
+	 */
+	if (index[0] == htonl(PACK_IDX_SIGNATURE))
+		return error("index file %s is a newer version"
+			" and is not supported by this binary"
+			" (try upgrading GIT to a newer version)",
+			path);
+
 	nr = 0;
 	for (i = 0; i < 256; i++) {
 		unsigned int n = ntohl(index[i]);
 		if (n < nr)
-			return error("non-monotonic index");
+			return error("non-monotonic index %s", path);
 		nr = n;
 	}
 
@@ -473,7 +483,7 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 	 *  - 20-byte SHA1 file checksum
 	 */
 	if (idx_size != 4*256 + nr * 24 + 20 + 20)
-		return error("wrong index file size");
+		return error("wrong index file size in %s", path);
 
 	return 0;
 }
@@ -541,7 +551,11 @@ void unuse_pack(struct pack_window **w_cursor)
 	}
 }
 
-static void open_packed_git(struct packed_git *p)
+/*
+ * Do not call this directly as this leaks p->pack_fd on error return;
+ * call open_packed_git() instead.
+ */
+static int open_packed_git_1(struct packed_git *p)
 {
 	struct stat st;
 	struct pack_header hdr;
@@ -551,47 +565,61 @@ static void open_packed_git(struct packed_git *p)
 
 	p->pack_fd = open(p->pack_name, O_RDONLY);
 	if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
-		die("packfile %s cannot be opened", p->pack_name);
+		return -1;
 
 	/* If we created the struct before we had the pack we lack size. */
 	if (!p->pack_size) {
 		if (!S_ISREG(st.st_mode))
-			die("packfile %s not a regular file", p->pack_name);
+			return error("packfile %s not a regular file", p->pack_name);
 		p->pack_size = st.st_size;
 	} else if (p->pack_size != st.st_size)
-		die("packfile %s size changed", p->pack_name);
+		return error("packfile %s size changed", p->pack_name);
 
 	/* We leave these file descriptors open with sliding mmap;
 	 * there is no point keeping them open across exec(), though.
 	 */
 	fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 	if (fd_flag < 0)
-		die("cannot determine file descriptor flags");
+		return error("cannot determine file descriptor flags");
 	fd_flag |= FD_CLOEXEC;
 	if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
-		die("cannot set FD_CLOEXEC");
+		return error("cannot set FD_CLOEXEC");
 
 	/* Verify we recognize this pack file format. */
-	read_or_die(p->pack_fd, &hdr, sizeof(hdr));
+	if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
+		return error("file %s is far too short to be a packfile", p->pack_name);
 	if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
-		die("file %s is not a GIT packfile", p->pack_name);
+		return error("file %s is not a GIT packfile", p->pack_name);
 	if (!pack_version_ok(hdr.hdr_version))
-		die("packfile %s is version %u and not supported"
+		return error("packfile %s is version %u and not supported"
 			" (try upgrading GIT to a newer version)",
 			p->pack_name, ntohl(hdr.hdr_version));
 
 	/* Verify the pack matches its index. */
 	if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
-		die("packfile %s claims to have %u objects"
+		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));
 	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
-		die("end of packfile %s is unavailable", p->pack_name);
-	read_or_die(p->pack_fd, sha1, sizeof(sha1));
+		return error("end of packfile %s is unavailable", p->pack_name);
+	if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
+		return error("packfile %s signature is unavailable", p->pack_name);
 	idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
 	if (hashcmp(sha1, idx_sha1))
-		die("packfile %s does not match index", p->pack_name);
+		return error("packfile %s does not match index", p->pack_name);
+	return 0;
+}
+
+static int open_packed_git(struct packed_git *p)
+{
+	if (!open_packed_git_1(p))
+		return 0;
+	if (p->pack_fd != -1) {
+		close(p->pack_fd);
+		p->pack_fd = -1;
+	}
+	return -1;
 }
 
 static int in_window(struct pack_window *win, unsigned long offset)
@@ -614,8 +642,8 @@ unsigned char* use_pack(struct packed_git *p,
 {
 	struct pack_window *win = *w_cursor;
 
-	if (p->pack_fd == -1)
-		open_packed_git(p);
+	if (p->pack_fd == -1 && open_packed_git(p))
+		die("packfile %s cannot be accessed", p->pack_name);
 
 	/* Since packfiles end in a hash of their content and its
 	 * pointless to ask for an offset into the middle of that
@@ -633,10 +661,9 @@ unsigned char* use_pack(struct packed_git *p,
 				break;
 		}
 		if (!win) {
-			if (!page_size)
-				page_size = getpagesize();
+			size_t window_align = packed_git_window_size / 2;
 			win = xcalloc(1, sizeof(*win));
-			win->offset = (offset / page_size) * page_size;
+			win->offset = (offset / window_align) * window_align;
 			win->len = p->pack_size - win->offset;
 			if (win->len > packed_git_window_size)
 				win->len = packed_git_window_size;
@@ -766,7 +793,7 @@ static void prepare_packed_git_one(char *objdir, int local)
 		if (!has_extension(de->d_name, ".idx"))
 			continue;
 
-		/* we have .idx.  Is it a file we can map? */
+		/* Don't reopen a pack we already have. */
 		strcpy(path + len, de->d_name);
 		for (p = packed_git; p; p = p->next) {
 			if (!memcmp(path, p->pack_name, len + namelen - 4))
@@ -774,11 +801,13 @@ static void prepare_packed_git_one(char *objdir, int local)
 		}
 		if (p)
 			continue;
+		/* See if it really is a valid .idx file with corresponding
+		 * .pack file that we can map.
+		 */
 		p = add_packed_git(path, len + namelen, local);
 		if (!p)
 			continue;
-		p->next = packed_git;
-		packed_git = p;
+		install_packed_git(p);
 	}
 	closedir(dir);
 }
@@ -1132,7 +1161,7 @@ static unsigned long unpack_object_header(struct packed_git *p,
 
 	/* use_pack() assures us we have [base, base + 20) available
 	 * as a range that we can look at at.  (Its actually the hash
-	 * size that is assurred.)  With our object header encoding
+	 * size that is assured.)  With our object header encoding
 	 * the maximum deflated object size is 2^137, which is just
 	 * insane, so we know won't exceed what we have been given.
 	 */
@@ -1338,7 +1367,7 @@ int nth_packed_object_sha1(const struct packed_git *p, int n,
 unsigned long find_pack_entry_one(const unsigned char *sha1,
 				  struct packed_git *p)
 {
-	unsigned int *level1_ofs = p->index_base;
+	uint32_t *level1_ofs = p->index_base;
 	int hi = ntohl(level1_ofs[*sha1]);
 	int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
 	void *index = p->index_base + 256;
@@ -1347,7 +1376,7 @@ unsigned long find_pack_entry_one(const unsigned char *sha1,
 		int mi = (lo + hi) / 2;
 		int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
 		if (!cmp)
-			return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
+			return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
 		if (cmp > 0)
 			hi = mi;
 		else
@@ -1392,6 +1421,18 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
 		}
 		offset = find_pack_entry_one(sha1, p);
 		if (offset) {
+			/*
+			 * We are about to tell the caller where they can
+			 * locate the requested object.  We better make
+			 * sure the packfile is still here and can be
+			 * accessed before supplying that answer, as
+			 * it may have been deleted since the index
+			 * was loaded!
+			 */
+			if (p->pack_fd == -1 && open_packed_git(p)) {
+				error("packfile %s cannot be accessed", p->pack_name);
+				continue;
+			}
 			e->offset = offset;
 			e->p = p;
 			hashcpy(e->sha1, sha1);
@@ -1456,21 +1497,79 @@ static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned lo
 {
 	struct pack_entry e;
 
-	if (!find_pack_entry(sha1, &e, NULL)) {
-		error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+	if (!find_pack_entry(sha1, &e, NULL))
 		return NULL;
+	else
+		return unpack_entry(e.p, e.offset, type, size);
+}
+
+/*
+ * This is meant to hold a *small* number of objects that you would
+ * want read_sha1_file() to be able to return, but yet you do not want
+ * to write them into the object store (e.g. a browse-only
+ * application).
+ */
+static struct cached_object {
+	unsigned char sha1[20];
+	const char *type;
+	void *buf;
+	unsigned long size;
+} *cached_objects;
+static int cached_object_nr, cached_object_alloc;
+
+static struct cached_object *find_cached_object(const unsigned char *sha1)
+{
+	int i;
+	struct cached_object *co = cached_objects;
+
+	for (i = 0; i < cached_object_nr; i++, co++) {
+		if (!hashcmp(co->sha1, sha1))
+			return co;
 	}
-	return unpack_entry(e.p, e.offset, type, size);
+	return NULL;
 }
 
-void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
+int pretend_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *sha1)
+{
+	struct cached_object *co;
+
+	hash_sha1_file(buf, len, type, sha1);
+	if (has_sha1_file(sha1) || find_cached_object(sha1))
+		return 0;
+	if (cached_object_alloc <= cached_object_nr) {
+		cached_object_alloc = alloc_nr(cached_object_alloc);
+		cached_objects = xrealloc(cached_objects,
+					  sizeof(*cached_objects) *
+					  cached_object_alloc);
+	}
+	co = &cached_objects[cached_object_nr++];
+	co->size = len;
+	co->type = strdup(type);
+	co->buf = xmalloc(len);
+	memcpy(co->buf, buf, len);
+	hashcpy(co->sha1, sha1);
+	return 0;
+}
+
+void *read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 {
 	unsigned long mapsize;
 	void *map, *buf;
-	struct pack_entry e;
+	struct cached_object *co;
+
+	co = find_cached_object(sha1);
+	if (co) {
+		buf = xmalloc(co->size + 1);
+		memcpy(buf, co->buf, co->size);
+		((char*)buf)[co->size] = 0;
+		strcpy(type, co->type);
+		*size = co->size;
+		return buf;
+	}
 
-	if (find_pack_entry(sha1, &e, NULL))
-		return read_packed_sha1(sha1, type, size);
+	buf = read_packed_sha1(sha1, type, size);
+	if (buf)
+		return buf;
 	map = map_sha1_file(sha1, &mapsize);
 	if (map) {
 		buf = unpack_sha1_file(map, mapsize, type, size);
@@ -1478,9 +1577,7 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
 		return buf;
 	}
 	reprepare_packed_git();
-	if (find_pack_entry(sha1, &e, NULL))
-		return read_packed_sha1(sha1, type, size);
-	return NULL;
+	return read_packed_sha1(sha1, type, size);
 }
 
 void *read_object_with_reference(const unsigned char *sha1,
@@ -1618,12 +1715,7 @@ int move_temp_to_file(const char *tmpfile, const char *filename)
 
 static int write_buffer(int fd, const void *buf, size_t len)
 {
-	ssize_t size;
-
-	size = write_in_full(fd, buf, len);
-	if (!size)
-		return error("file write: disk full");
-	if (size < 0)
+	if (write_in_full(fd, buf, len) < 0)
 		return error("file write error (%s)", strerror(errno));
 	return 0;
 }
@@ -1773,6 +1865,8 @@ static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
 
 	/* 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", type, len) + 1;
 
@@ -1997,6 +2091,7 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, con
 
 	if (!type)
 		type = blob_type;
+	/* FIXME: CRLF -> LF conversion here for blobs! We'll need the path! */
 	if (write_object)
 		ret = write_sha1_file(buf, size, type, sha1);
 	else
@@ -2041,3 +2136,24 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 	}
 	return 0;
 }
+
+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 (header->hdr_signature != htonl(PACK_SIGNATURE))
+		/* "protocol error (pack signature mismatch detected)" */
+		return PH_ERROR_PACK_SIGNATURE;
+	if (!pack_version_ok(header->hdr_version))
+		/* "protocol error (pack version unsupported)" */
+		return PH_ERROR_PROTOCOL;
+	return 0;
+}