From 2e820abea1ef62c1969ee17878f14ff2f4d224e8 Mon Sep 17 00:00:00 2001
From: Denis Kenzior <denkenz@gmail.com>
Date: Thu, 16 Mar 2017 15:13:35 -0500
Subject: [PATCH] backtrace: Try to find absolute executable path

This allows us to get backtraces from test_runner which does not start
iwd from a current working directory that is a parent of the iwd
executable.
---
 src/backtrace.c | 25 ++++++++++++++++++++++---
 src/backtrace.h |  2 +-
 src/main.c      |  2 +-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/backtrace.c b/src/backtrace.c
index ec4c4701..759a8431 100644
--- a/src/backtrace.c
+++ b/src/backtrace.c
@@ -156,14 +156,33 @@ static void signal_handler(int signo)
 	exit(EXIT_FAILURE);
 }
 
-void __iwd_backtrace_init(const char *program)
+void __iwd_backtrace_init()
 {
 	static char path[PATH_MAX];
+	static char cwd[PATH_MAX];
 	struct sigaction sa;
 	sigset_t mask;
+	ssize_t len;
 
-	program_exec = program;
-	program_path = getcwd(path, sizeof(path));
+	/* Attempt to get the full path to our executable */
+	len = readlink("/proc/self/exe", path, sizeof(path) - 1);
+	if (len > 0) {
+		int i;
+		path[len] = '\0';
+
+		for (i = len - 1; i >= 0; i--) {
+			if (path[i] != '/')
+				continue;
+
+			program_exec = path;
+			break;
+		}
+	}
+
+	if (program_exec == NULL)
+		return;
+
+	program_path = getcwd(cwd, sizeof(cwd));
 
 	sigemptyset(&mask);
 	sa.sa_handler = signal_handler;
diff --git a/src/backtrace.h b/src/backtrace.h
index 973466a0..bfdc8583 100644
--- a/src/backtrace.h
+++ b/src/backtrace.h
@@ -20,6 +20,6 @@
  *
  */
 #ifdef __GLIBC__
-void __iwd_backtrace_init(const char *program);
+void __iwd_backtrace_init();
 void __iwd_backtrace_print(unsigned int offset);
 #endif
diff --git a/src/main.c b/src/main.c
index a75b3a34..3eb79486 100644
--- a/src/main.c
+++ b/src/main.c
@@ -197,7 +197,7 @@ int main(int argc, char *argv[])
 	l_debug_enable("*");
 
 #ifdef __GLIBC__
-	__iwd_backtrace_init(argv[0]);
+	__iwd_backtrace_init();
 #endif
 
 	l_info("Wireless daemon version %s", VERSION);