emulator: Move trace dump to a separate module

The implementation of trace dump has little to do with task scheduling,
so we should move it to a separate module for cleaner code. This
requires exposing some emulator-specific task info, as defined in
host_task.h.

BUG=chrome-os-partner:19235
TEST=Pass all tests
BRANCH=None

Change-Id: Iba9bc0794a4e1dd4ddb92b98345162b398fa6a8d
Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/183238

1 files changed, 97 insertions, 0 deletions

diff --git a/core/host/stack_trace.c b/core/host/stack_trace.c
new file mode 100644
index 0000000000..67ceac5891
--- /dev/null
+++ b/core/host/stack_trace.c
@@ -0,0 +1,97 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <execinfo.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "host_task.h"
+#include "host_test.h"
+#include "timer.h"
+
+#define SIGNAL_TRACE_DUMP SIGTERM
+#define MAX_TRACE 30
+/*
+ * When trace dump is requested from signal handler, skip:
+ *   _task_dump_trace_impl
+ *   _task_dump_trace_dispath
+ *   A function in libc
+ */
+#define SIGNAL_TRACE_OFFSET 3
+/*
+ * When trace dump is requested from task_dump_trace(), skip:
+ *   task_dump_trace
+ *   _task_dump_trace_impl
+ */
+#define DIRECT_TRACE_OFFSET 2
+
+static pthread_t main_thread;
+
+static void __attribute__((noinline)) _task_dump_trace_impl(int offset)
+{
+	void *trace[MAX_TRACE];
+	size_t sz;
+	char **messages;
+	char buf[256];
+	FILE *file;
+	int i, nb;
+
+	sz = backtrace(trace, MAX_TRACE);
+	messages = backtrace_symbols(trace + offset, sz - offset);
+
+	for (i = 0; i < sz - offset; ++i) {
+		fprintf(stderr, "#%-2d %s\n", i, messages[i]);
+		sprintf(buf, "addr2line %p -e %s",
+			trace[i + offset], __get_prog_name());
+		file = popen(buf, "r");
+		if (file) {
+			nb = fread(buf, 1, sizeof(buf) - 1, file);
+			buf[nb] = '\0';
+			fprintf(stderr, "    %s", buf);
+			pclose(file);
+		}
+	}
+	fflush(stderr);
+	free(messages);
+}
+
+void __attribute__((noinline)) task_dump_trace(void)
+{
+	_task_dump_trace_impl(DIRECT_TRACE_OFFSET);
+}
+
+static void __attribute__((noinline)) _task_dump_trace_dispatch(int sig)
+{
+	int need_dispatch = 1;
+	task_id_t running = task_get_running();
+
+	if (!pthread_equal(pthread_self(), main_thread)) {
+		need_dispatch = 0;
+	} else if (!task_start_called()) {
+		fprintf(stderr, "Stack trace of main thread:\n");
+		need_dispatch = 0;
+	} else if (in_interrupt_context()) {
+		fprintf(stderr, "Stack trace of ISR:\n");
+	} else {
+		fprintf(stderr, "Stack trace of task %d (%s):\n",
+				running, task_get_name(running));
+	}
+
+	if (need_dispatch) {
+		pthread_kill(task_get_thread(running), SIGNAL_TRACE_DUMP);
+	} else {
+		_task_dump_trace_impl(SIGNAL_TRACE_OFFSET);
+		udelay(100 * MSEC); /* Leave time for stderr to flush */
+		exit(1);
+	}
+}
+
+void task_register_tracedump(void)
+{
+	/* Trace dumper MUST be registered from main thread */
+	main_thread = pthread_self();
+	signal(SIGNAL_TRACE_DUMP, _task_dump_trace_dispatch);
+}