From 2df269a3121889ebcdfa5d98dfb4d675f690e039 Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Fri, 27 Jul 2012 15:59:13 +0200
Subject: [PATCH] Canonicalize paths when computing path relative to base
 directory

This fixes a bug when current working directory contains a "/./" part.

Based on a patch by Eric Blau.
---
 ccache.c | 16 ++++++++++++++--
 util.c   |  3 ++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/ccache.c b/ccache.c
index 79221b8b1..1f8ee64eb 100644
--- a/ccache.c
+++ b/ccache.c
@@ -386,14 +386,18 @@ ignore:
 static char *
 make_relative_path(char *path)
 {
-	char *relpath;
+	char *relpath, *canon_path;
 
 	if (!base_dir || !str_startswith(path, base_dir)) {
 		return path;
 	}
 
 	if (!current_working_dir) {
-		current_working_dir = get_cwd();
+		char *cwd = get_cwd();
+		if (cwd) {
+			current_working_dir = x_realpath(cwd);
+			free(cwd);
+		}
 		if (!current_working_dir) {
 			cc_log("Unable to determine current working directory: %s",
 			       strerror(errno));
@@ -401,6 +405,14 @@ make_relative_path(char *path)
 		}
 	}
 
+	canon_path = x_realpath(path);
+	if (canon_path) {
+		free(path);
+		path = canon_path;
+	} else {
+		/* path doesn't exist, so leave it as it is. */
+	}
+
 	relpath = get_relative_path(current_working_dir, path);
 	free(path);
 	return relpath;
diff --git a/util.c b/util.c
index 3086b2c62..acfcd9db6 100644
--- a/util.c
+++ b/util.c
@@ -984,7 +984,8 @@ common_dir_prefix_length(const char *s1, const char *s2)
 }
 
 /*
- * Compute a relative path from from to to. Caller frees.
+ * Compute a relative path from from to to. Assumes that both from and to are
+ * well-formed and canonical. Caller frees.
  */
 char *
 get_relative_path(const char *from, const char *to)
-- 
2.47.2