1 files changed, 48 insertions, 0 deletions
diff --git a/symlinks.c b/symlinks.c
new file mode 100644
index 0000000000..be9ace6c04
--- /dev/null
+++ b/symlinks.c
@@ -0,0 +1,48 @@
+#include "cache.h"
+
+int has_symlink_leading_path(const char *name, char *last_symlink)
+{
+	char path[PATH_MAX];
+	const char *sp, *ep;
+	char *dp;
+
+	sp = name;
+	dp = path;
+
+	if (last_symlink && *last_symlink) {
+		size_t last_len = strlen(last_symlink);
+		size_t len = strlen(name);
+		if (last_len < len &&
+		    !strncmp(name, last_symlink, last_len) &&
+		    name[last_len] == '/')
+			return 1;
+		*last_symlink = '\0';
+	}
+
+	while (1) {
+		size_t len;
+		struct stat st;
+
+		ep = strchr(sp, '/');
+		if (!ep)
+			break;
+		len = ep - sp;
+		if (PATH_MAX <= dp + len - path + 2)
+			return 0; /* new name is longer than that??? */
+		memcpy(dp, sp, len);
+		dp[len] = 0;
+
+		if (lstat(path, &st))
+			return 0;
+		if (S_ISLNK(st.st_mode)) {
+			if (last_symlink)
+				strcpy(last_symlink, path);
+			return 1;
+		}
+
+		dp[len++] = '/';
+		dp = dp + len;
+		sp = ep + 1;
+	}
+	return 0;
+}