From a9dc850d06ecb6aa3b15c4afaadc4cc0300d794a Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Thu, 8 Aug 2013 18:06:16 +0200
Subject: [PATCH] Fix path canonicalization in make_relative_path when path
 doesn't exist

---
 ccache.c                        |   40 +++++++++++++++++++++++++++++++++------
 test/test_argument_processing.c |   19 +++++++++----------
 2 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/ccache.c b/ccache.c
index 38652e1..c02868f 100644
--- a/ccache.c
+++ b/ccache.c
@@ -387,12 +387,14 @@ ignore:
 static char *
 make_relative_path(char *path)
 {
-	char *relpath, *canon_path;
+	char *relpath, *canon_path, *path_suffix = NULL;
+	struct stat st;
 
 	if (!base_dir || !str_startswith(path, base_dir)) {
 		return path;
 	}
 
+	/* Look up CWD and cache it in the global current_working_dir variable. */
 	if (!current_working_dir) {
 		char *cwd = get_cwd();
 		if (cwd) {
@@ -406,17 +408,43 @@ make_relative_path(char *path)
 		}
 	}
 
+	/* x_realpath only works for existing paths, so if path doesn't exist, try
+	 * dirname(path) and assemble the path afterwards. We only bother to try
+	 * canonicalizing one of these two paths since a compiler path argument
+	 * typically only makes sense if path or dirname(path) exists. */
+	if (stat(path, &st) != 0) {
+		/* path doesn't exist. */
+		char *dir, *p;
+		dir = dirname(path);
+		if (stat(dir, &st) != 0) {
+			/* And neither does its parent directory, so no action to take. */
+			free(dir);
+			return path;
+		}
+		path_suffix = basename(path);
+		p = path;
+		path = dirname(path);
+		free(p);
+	}
+
 	canon_path = x_realpath(path);
 	if (canon_path) {
 		free(path);
-		path = canon_path;
+		relpath = get_relative_path(current_working_dir, canon_path);
+		free(canon_path);
+		if (path_suffix) {
+			path = format("%s/%s", relpath, path_suffix);
+			free(relpath);
+			free(path_suffix);
+			return path;
+		} else {
+			return relpath;
+		}
 	} else {
 		/* path doesn't exist, so leave it as it is. */
+		free(path_suffix);
+		return path;
 	}
-
-	relpath = get_relative_path(current_working_dir, path);
-	free(path);
-	return relpath;
 }
 
 /*
diff --git a/test/test_argument_processing.c b/test/test_argument_processing.c
index 94e46f4..6ed0daa 100644
--- a/test/test_argument_processing.c
+++ b/test/test_argument_processing.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2012 Joel Rosdahl
+ * Copyright (C) 2010-2013 Joel Rosdahl
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
@@ -90,20 +90,19 @@ TEST(sysroot_should_be_rewritten_if_basedir_is_used)
 {
 	extern char *base_dir;
 	extern char *current_working_dir;
-	struct args *orig =
-		args_init_from_string("cc --sysroot=/some/directory -c foo.c");
+	char *arg_string;
+	struct args *orig;
 	struct args *act_cpp = NULL, *act_cc = NULL;
-	create_file("foo.c", "");
-
-	CHECK(cc_process_args(orig, &act_cpp, &act_cc));
-	CHECK_STR_EQ(act_cpp->argv[1], "--sysroot=/some/directory");
 
-	cc_reset();
-	base_dir = "/some";
+	create_file("foo.c", "");
 	current_working_dir = get_cwd();
+	arg_string = format("cc --sysroot=%s/foo -c foo.c", current_working_dir);
+	orig = args_init_from_string(arg_string);
+
+	base_dir = "/";
 
 	CHECK(cc_process_args(orig, &act_cpp, &act_cc));
-	CHECK(str_startswith(act_cpp->argv[1], "--sysroot=../"));
+	CHECK(str_startswith(act_cpp->argv[1], "--sysroot=./foo"));
 
 	args_free(orig);
 	base_dir = NULL;
-- 
1.7.10.4