1 files changed, 113 insertions, 25 deletions

diff --git a/sha1_file.c b/sha1_file.c
index 27730c334c..b4fcca8ffd 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -13,6 +13,7 @@
 #include "commit.h"
 #include "tag.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "refs.h"
 #include "pack-revindex.h"
 #include "sha1-lookup.h"
@@ -417,6 +418,8 @@ static unsigned int pack_used_ctr;
 static unsigned int pack_mmap_calls;
 static unsigned int peak_pack_open_windows;
 static unsigned int pack_open_windows;
+static unsigned int pack_open_fds;
+static unsigned int pack_max_fds;
 static size_t peak_pack_mapped;
 static size_t pack_mapped;
 struct packed_git *packed_git;
@@ -594,8 +597,10 @@ static int unuse_one_window(struct packed_git *current, int keep_fd)
 			lru_l->next = lru_w->next;
 		else {
 			lru_p->windows = lru_w->next;
-			if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
+			if (!lru_p->windows && lru_p->pack_fd != -1
+				&& lru_p->pack_fd != keep_fd) {
 				close(lru_p->pack_fd);
+				pack_open_fds--;
 				lru_p->pack_fd = -1;
 			}
 		}
@@ -680,8 +685,10 @@ void free_pack_by_name(const char *pack_name)
 		if (strcmp(pack_name, p->pack_name) == 0) {
 			clear_delta_base_cache();
 			close_pack_windows(p);
-			if (p->pack_fd != -1)
+			if (p->pack_fd != -1) {
 				close(p->pack_fd);
+				pack_open_fds--;
+			}
 			close_pack_index(p);
 			free(p->bad_object_sha1);
 			*pp = p->next;
@@ -707,9 +714,29 @@ static int open_packed_git_1(struct packed_git *p)
 	if (!p->index_data && open_pack_index(p))
 		return error("packfile %s index unavailable", p->pack_name);
 
+	if (!pack_max_fds) {
+		struct rlimit lim;
+		unsigned int max_fds;
+
+		if (getrlimit(RLIMIT_NOFILE, &lim))
+			die_errno("cannot get RLIMIT_NOFILE");
+
+		max_fds = lim.rlim_cur;
+
+		/* Save 3 for stdin/stdout/stderr, 22 for work */
+		if (25 < max_fds)
+			pack_max_fds = max_fds - 25;
+		else
+			pack_max_fds = 1;
+	}
+
+	while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1))
+		; /* nothing */
+
 	p->pack_fd = git_open_noatime(p->pack_name, p);
 	if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 		return -1;
+	pack_open_fds++;
 
 	/* If we created the struct before we had the pack we lack size. */
 	if (!p->pack_size) {
@@ -761,6 +788,7 @@ static int open_packed_git(struct packed_git *p)
 		return 0;
 	if (p->pack_fd != -1) {
 		close(p->pack_fd);
+		pack_open_fds--;
 		p->pack_fd = -1;
 	}
 	return -1;
@@ -786,14 +814,13 @@ unsigned char *use_pack(struct packed_git *p,
 {
 	struct pack_window *win = *w_cursor;
 
-	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 it's
 	 * pointless to ask for an offset into the middle of that
 	 * hash, and the in_window function above wouldn't match
 	 * don't allow an offset too close to the end of the file.
 	 */
+	if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
+		die("packfile %s cannot be accessed", p->pack_name);
 	if (offset > (p->pack_size - 20))
 		die("offset beyond end of packfile (truncated pack?)");
 
@@ -807,6 +834,10 @@ unsigned char *use_pack(struct packed_git *p,
 		if (!win) {
 			size_t window_align = packed_git_window_size / 2;
 			off_t len;
+
+			if (p->pack_fd == -1 && open_packed_git(p))
+				die("packfile %s cannot be accessed", p->pack_name);
+
 			win = xcalloc(1, sizeof(*win));
 			win->offset = (offset / window_align) * window_align;
 			len = p->pack_size - win->offset;
@@ -824,6 +855,12 @@ unsigned char *use_pack(struct packed_git *p,
 				die("packfile %s cannot be mapped: %s",
 					p->pack_name,
 					strerror(errno));
+			if (!win->offset && win->len == p->pack_size
+				&& !p->do_not_close) {
+				close(p->pack_fd);
+				pack_open_fds--;
+				p->pack_fd = -1;
+			}
 			pack_mmap_calls++;
 			pack_open_windows++;
 			if (pack_mapped > peak_pack_mapped)
@@ -918,6 +955,9 @@ struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 
 void install_packed_git(struct packed_git *pack)
 {
+	if (pack->pack_fd != -1)
+		pack_open_fds++;
+
 	pack->next = packed_git;
 	packed_git = pack;
 }
@@ -935,8 +975,6 @@ static void prepare_packed_git_one(char *objdir, int local)
 	sprintf(path, "%s/pack", objdir);
 	len = strlen(path);
 	dir = opendir(path);
-	while (!dir && errno == EMFILE && unuse_one_window(NULL, -1))
-		dir = opendir(path);
 	if (!dir) {
 		if (errno != ENOENT)
 			error("unable to open object pack directory: %s: %s",
@@ -1092,14 +1130,6 @@ static int git_open_noatime(const char *name, struct packed_git *p)
 		if (fd >= 0)
 			return fd;
 
-		/* Might the failure be insufficient file descriptors? */
-		if (errno == EMFILE) {
-			if (unuse_one_window(p, -1))
-				continue;
-			else
-				return -1;
-		}
-
 		/* Might the failure be due to O_NOATIME? */
 		if (errno != ENOENT && sha1_file_open_flag) {
 			sha1_file_open_flag = 0;
@@ -1931,6 +1961,27 @@ off_t find_pack_entry_one(const unsigned char *sha1,
 	return 0;
 }
 
+static int is_pack_valid(struct packed_git *p)
+{
+	/* An already open pack is known to be valid. */
+	if (p->pack_fd != -1)
+		return 1;
+
+	/* If the pack has one window completely covering the
+	 * file size, the pack is known to be valid even if
+	 * the descriptor is not currently open.
+	 */
+	if (p->windows) {
+		struct pack_window *w = p->windows;
+
+		if (!w->offset && w->len == p->pack_size)
+			return 1;
+	}
+
+	/* Force the pack to open to prove its valid. */
+	return !open_packed_git(p);
+}
+
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 {
 	static struct packed_git *last_found = (void *)1;
@@ -1960,7 +2011,7 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 			 * it may have been deleted since the index
 			 * was loaded!
 			 */
-			if (p->pack_fd == -1 && open_packed_git(p)) {
+			if (!is_pack_valid(p)) {
 				error("packfile %s cannot be accessed", p->pack_name);
 				goto next;
 			}
@@ -2359,8 +2410,6 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 
 	filename = sha1_file_name(sha1);
 	fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
-	while (fd < 0 && errno == EMFILE && unuse_one_window(NULL, -1))
-		fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
 	if (fd < 0) {
 		if (errno == EACCES)
 			return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
@@ -2479,8 +2528,37 @@ int has_sha1_file(const unsigned char *sha1)
 	return has_loose_object(sha1);
 }
 
+static void check_tree(const void *buf, size_t size)
+{
+	struct tree_desc desc;
+	struct name_entry entry;
+
+	init_tree_desc(&desc, buf, size);
+	while (tree_entry(&desc, &entry))
+		/* do nothing
+		 * tree_entry() will die() on malformed entries */
+		;
+}
+
+static void check_commit(const void *buf, size_t size)
+{
+	struct commit c;
+	memset(&c, 0, sizeof(c));
+	if (parse_commit_buffer(&c, buf, size))
+		die("corrupt commit");
+}
+
+static void check_tag(const void *buf, size_t size)
+{
+	struct tag t;
+	memset(&t, 0, sizeof(t));
+	if (parse_tag_buffer(&t, buf, size))
+		die("corrupt tag");
+}
+
 static int index_mem(unsigned char *sha1, void *buf, size_t size,
-		     int write_object, enum object_type type, const char *path)
+		     int write_object, enum object_type type,
+		     const char *path, int format_check)
 {
 	int ret, re_allocated = 0;
 
@@ -2498,6 +2576,14 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
 			re_allocated = 1;
 		}
 	}
+	if (format_check) {
+		if (type == OBJ_TREE)
+			check_tree(buf, size);
+		if (type == OBJ_COMMIT)
+			check_commit(buf, size);
+		if (type == OBJ_TAG)
+			check_tag(buf, size);
+	}
 
 	if (write_object)
 		ret = write_sha1_file(buf, size, typename(type), sha1);
@@ -2511,7 +2597,7 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
 #define SMALL_FILE_SIZE (32*1024)
 
 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
-	     enum object_type type, const char *path)
+	     enum object_type type, const char *path, int format_check)
 {
 	int ret;
 	size_t size = xsize_t(st->st_size);
@@ -2520,23 +2606,25 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
 		struct strbuf sbuf = STRBUF_INIT;
 		if (strbuf_read(&sbuf, fd, 4096) >= 0)
 			ret = index_mem(sha1, sbuf.buf, sbuf.len, write_object,
-					type, path);
+					type, path, format_check);
 		else
 			ret = -1;
 		strbuf_release(&sbuf);
 	} else if (!size) {
-		ret = index_mem(sha1, NULL, size, write_object, type, path);
+		ret = index_mem(sha1, NULL, size, write_object, type, path,
+				format_check);
 	} else if (size <= SMALL_FILE_SIZE) {
 		char *buf = xmalloc(size);
 		if (size == read_in_full(fd, buf, size))
 			ret = index_mem(sha1, buf, size, write_object, type,
-					path);
+					path, format_check);
 		else
 			ret = error("short read %s", strerror(errno));
 		free(buf);
 	} else {
 		void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
-		ret = index_mem(sha1, buf, size, write_object, type, path);
+		ret = index_mem(sha1, buf, size, write_object, type, path,
+				format_check);
 		munmap(buf, size);
 	}
 	close(fd);
@@ -2554,7 +2642,7 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 		if (fd < 0)
 			return error("open(\"%s\"): %s", path,
 				     strerror(errno));
-		if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
+		if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path, 0) < 0)
 			return error("%s: failed to insert into database",
 				     path);
 		break;