From 867275636c6b2526f6626e503e8e72a21776370f Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Tue, 16 Apr 2013 19:57:51 +0200
Subject: [PATCH] Canonicalize paths, so that we do not need to worry about cwd
 on re-exec.

---
 main.cpp | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/main.cpp b/main.cpp
index b927237..75c36d8 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <getopt.h>
+#include <limits.h>
 #include <signal.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -269,8 +270,22 @@ int main(int argc, char **argv)
 		config_filename = argv[optind++];
 	}
 
+	// Canonicalize argv[0] and config_filename.
+	char argv0_canon[PATH_MAX];
+	char config_filename_canon[PATH_MAX];
+
+	if (realpath(argv[0], argv0_canon) == NULL) {
+		log_perror("realpath");
+		exit(1);
+	}
+	if (realpath(config_filename.c_str(), config_filename_canon) == NULL) {
+		log_perror("realpath");
+		exit(1);
+	}
+
+	// Now parse the configuration file.
 	Config config;
-	if (!parse_config(config_filename, &config)) {
+	if (!parse_config(config_filename_canon, &config)) {
 		exit(1);
 	}
 	if (test_config) {
@@ -414,10 +429,10 @@ start:
 	sprintf(buf, "%d", state_fd);
 
 	for ( ;; ) {
-		execlp(argv[0], argv[0], config_filename.c_str(), "--state", buf, NULL);
+		execlp(argv0_canon, argv0_canon, config_filename_canon, "--state", buf, NULL);
 		open_logs(config.log_destinations);
 		log_perror("execlp");
-		log(ERROR, "re-exec of %s failed. Waiting 0.2 seconds and trying again...", argv[0]);
+		log(ERROR, "re-exec of %s failed. Waiting 0.2 seconds and trying again...", argv0_canon);
 		shut_down_logging();
 		usleep(200000);
 	}
-- 
2.39.2