1 files changed, 68 insertions, 1 deletions
diff --git a/wrapper.c b/wrapper.c
index 8b98593149..2f00d2ac87 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -737,7 +737,26 @@ int is_empty_or_missing_file(const char *filename)
 int open_nofollow(const char *path, int flags)
 {
 #ifdef O_NOFOLLOW
-	return open(path, flags | O_NOFOLLOW);
+	int ret = open(path, flags | O_NOFOLLOW);
+	/*
+	 * NetBSD sets errno to EFTYPE when path is a symlink. The only other
+	 * time this errno occurs when O_REGULAR is used. Since we don't use
+	 * it anywhere we can avoid an lstat here. FreeBSD does the same with
+	 * EMLINK.
+	 */
+# ifdef __NetBSD__
+#  define SYMLINK_ERRNO EFTYPE
+# elif defined(__FreeBSD__)
+#  define SYMLINK_ERRNO EMLINK
+# endif
+# if SYMLINK_ERRNO
+	if (ret < 0 && errno == SYMLINK_ERRNO) {
+		errno = ELOOP;
+		return -1;
+	}
+#  undef SYMLINK_ERRNO
+# endif
+	return ret;
 #else
 	struct stat st;
 	if (lstat(path, &st) < 0)
@@ -829,3 +848,51 @@ uint32_t git_rand(unsigned flags)
 
 	return result;
 }
+
+static void mmap_limit_check(size_t length)
+{
+	static size_t limit = 0;
+	if (!limit) {
+		limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
+		if (!limit)
+			limit = SIZE_MAX;
+	}
+	if (length > limit)
+		die(_("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX),
+		    (uintmax_t)length, (uintmax_t)limit);
+}
+
+void *xmmap_gently(void *start, size_t length,
+		  int prot, int flags, int fd, off_t offset)
+{
+	void *ret;
+
+	mmap_limit_check(length);
+	ret = mmap(start, length, prot, flags, fd, offset);
+	if (ret == MAP_FAILED && !length)
+		ret = NULL;
+	return ret;
+}
+
+const char *mmap_os_err(void)
+{
+	static const char blank[] = "";
+#if defined(__linux__)
+	if (errno == ENOMEM) {
+		/* this continues an existing error message: */
+		static const char enomem[] =
+", check sys.vm.max_map_count and/or RLIMIT_DATA";
+		return enomem;
+	}
+#endif /* OS-specific bits */
+	return blank;
+}
+
+void *xmmap(void *start, size_t length,
+	int prot, int flags, int fd, off_t offset)
+{
+	void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
+	if (ret == MAP_FAILED)
+		die_errno(_("mmap failed%s"), mmap_os_err());
+	return ret;
+}