main: Add backtracing support

Ported from oFono @ commit df5d691c39b0ff41d3d98a01db078f7157eb0250.

Makefile.am

@@ -71,8 +71,9 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h \
 					src/wsc.h src/wsc.c \
 					src/eap.h src/eap.c \
 					src/eap-tls.c src/eap-ttls.c \
+					src/backtrace.h src/backtrace.c \
 					src/iwd.h
-src_iwd_LDADD = ell/libell-internal.la
+src_iwd_LDADD = ell/libell-internal.la -ldl
 
 client_iwctl_SOURCES = client/main.c src/kdbus.h src/kdbus.c
 client_iwctl_LDADD = ell/libell-internal.la

src/backtrace.c

@@ -0,0 +1,179 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2013-2016  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#define _GNU_SOURCE
+#include <features.h>
+
+#ifdef __GLIBC__
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <execinfo.h>
+#include <dlfcn.h>
+#include <linux/limits.h>
+
+#include <ell/ell.h>
+
+#include "src/backtrace.h"
+
+static const char *program_exec;
+static const char *program_path;
+
+void __iwd_backtrace_print(unsigned int offset)
+{
+	void *frames[99];
+	size_t n_ptrs;
+	unsigned int i;
+	int outfd[2], infd[2];
+	int pathlen;
+	pid_t pid;
+
+	if (program_exec == NULL)
+		return;
+
+	pathlen = strlen(program_path);
+
+	n_ptrs = backtrace(frames, L_ARRAY_SIZE(frames));
+	if (n_ptrs < offset)
+		return;
+
+	if (pipe(outfd) < 0)
+		return;
+
+	if (pipe(infd) < 0) {
+		close(outfd[0]);
+		close(outfd[1]);
+		return;
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		close(outfd[0]);
+		close(outfd[1]);
+		close(infd[0]);
+		close(infd[1]);
+		return;
+	}
+
+	if (pid == 0) {
+		close(outfd[1]);
+		close(infd[0]);
+
+		dup2(outfd[0], STDIN_FILENO);
+		dup2(infd[1], STDOUT_FILENO);
+
+		execlp("addr2line", "-C", "-f", "-e", program_exec, NULL);
+
+		exit(EXIT_FAILURE);
+	}
+
+	close(outfd[0]);
+	close(infd[1]);
+
+	l_error("++++++++ backtrace ++++++++");
+
+	for (i = offset; i < n_ptrs - 1; i++) {
+		Dl_info info;
+		char addr[20], buf[PATH_MAX * 2];
+		int len, written;
+		char *ptr, *pos;
+
+		dladdr(frames[i], &info);
+
+		len = snprintf(addr, sizeof(addr), "%p\n", frames[i]);
+		if (len < 0)
+			break;
+
+		written = write(outfd[1], addr, len);
+		if (written < 0)
+			break;
+
+		len = read(infd[0], buf, sizeof(buf));
+		if (len < 0)
+			break;
+
+		buf[len] = '\0';
+
+		pos = strchr(buf, '\n');
+		*pos++ = '\0';
+
+		if (strcmp(buf, "??") == 0) {
+			l_error("#%-2u %p in %s", i - offset,
+						frames[i], info.dli_fname);
+			continue;
+		}
+
+		ptr = strchr(pos, '\n');
+		*ptr++ = '\0';
+
+		if (strncmp(pos, program_path, pathlen) == 0)
+			pos += pathlen + 1;
+
+		l_error("#%-2u %p in %s() at %s", i - offset,
+						frames[i], buf, pos);
+	}
+
+	l_error("+++++++++++++++++++++++++++");
+
+	kill(pid, SIGTERM);
+
+	close(outfd[1]);
+	close(infd[0]);
+}
+
+static void signal_handler(int signo)
+{
+	l_error("Aborting (signal %d) [%s]", signo, program_exec);
+
+	__iwd_backtrace_print(2);
+
+	exit(EXIT_FAILURE);
+}
+
+void __iwd_backtrace_init(const char *program)
+{
+	static char path[PATH_MAX];
+	struct sigaction sa;
+	sigset_t mask;
+
+	program_exec = program;
+	program_path = getcwd(path, sizeof(path));
+
+	sigemptyset(&mask);
+	sa.sa_handler = signal_handler;
+	sa.sa_mask = mask;
+	sa.sa_flags = 0;
+	sigaction(SIGBUS, &sa, NULL);
+	sigaction(SIGILL, &sa, NULL);
+	sigaction(SIGFPE, &sa, NULL);
+	sigaction(SIGSEGV, &sa, NULL);
+	sigaction(SIGABRT, &sa, NULL);
+	sigaction(SIGPIPE, &sa, NULL);
+}
+#endif

src/backtrace.h

@@ -0,0 +1,25 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2013-2016  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+#ifdef __GLIBC__
+void __iwd_backtrace_init(const char *program);
+void __iwd_backtrace_print(unsigned int offset);
+#endif

src/main.c

@@ -40,6 +40,8 @@
 #include "src/scan.h"
 #include "src/wsc.h"
 
+#include "src/backtrace.h"
+
 static struct l_timeout *timeout = NULL;
 
 static void main_loop_quit(struct l_timeout *timeout, void *user_data)
@@ -162,6 +164,10 @@ int main(int argc, char *argv[])
 	l_log_set_stderr();
 	l_debug_enable("*");
 
+#ifdef __GLIBC__
+	__iwd_backtrace_init(argv[0]);
+#endif
+
 	l_info("Wireless daemon version %s", VERSION);
 
 	if (!dbus_init(enable_dbus_debug, enable_kdbus)) {