dev: option not to do backtracing.

It crashes under valgrind, causing a valgrind error: valgrind gives us a
backtrace anyway, so we don't need it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/log.c

@@ -18,6 +18,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#if DEVELOPER
+bool dev_no_backtrace;
+#endif
+
 static struct backtrace_state *backtrace_state;
 
 struct log_entry {
@@ -432,8 +436,9 @@ static void log_crash(int sig)
 
 	if (sig) {
 		log_broken(crashlog, "FATAL SIGNAL %i RECEIVED", sig);
-		backtrace_full(backtrace_state, 0, log_backtrace, NULL,
-			       crashlog);
+		if (backtrace_state)
+			backtrace_full(backtrace_state, 0, log_backtrace, NULL,
+				       crashlog);
 	}
 
 	if (crashlog->lr->print == log_default_print) {
@@ -457,7 +462,8 @@ static void log_crash(int sig)
 
 	if (sig) {
 		fprintf(stderr, "Fatal signal %u. ", sig);
-		backtrace_print(backtrace_state, 0, stderr);
+		if (backtrace_state)
+			backtrace_print(backtrace_state, 0, stderr);
 	}
 	if (logfile)
 		fprintf(stderr, "Log dumped in %s", logfile);
@@ -469,6 +475,9 @@ void crashlog_activate(const char *argv0, struct log *log)
 	struct sigaction sa;
 	crashlog = log;
 
+#if DEVELOPER
+	if (!dev_no_backtrace)
+#endif
 	backtrace_state = backtrace_create_state(argv0, 0, NULL, NULL);
 	sa.sa_handler = log_crash;
 	sigemptyset(&sa.sa_mask);

lightningd/log.h

@@ -94,4 +94,8 @@ const tal_t *ltmp;
 
 /* Before the crashlog is activated, just prints to stderr. */
 void NORETURN PRINTF_FMT(1,2) fatal(const char *fmt, ...);
+
+#if DEVELOPER
+extern bool dev_no_backtrace;
+#endif
 #endif /* LIGHTNING_LIGHTNINGD_LOG_H */

lightningd/options.c

@@ -288,6 +288,9 @@ static void dev_register_opts(struct lightningd *ld)
 			 NULL, ld, "File containing disconnection points");
 	opt_register_arg("--dev-hsm-seed=<seed>", opt_set_hsm_seed,
 			 NULL, ld, "Hex-encoded seed for HSM");
+	opt_register_noarg("--dev-no-backtrace", opt_set_bool,
+			   &dev_no_backtrace,
+			   "Disable backtrace (crashes under valgrind)");
 }
 #endif
 

tests/test_lightningd.py

@@ -107,6 +107,8 @@ class NodeFactory(object):
             daemon.cmd_line.append("--dev-disconnect=dev_disconnect")
         if DEVELOPER:
             daemon.cmd_line.append("--dev-fail-on-subdaemon-fail")
+            if VALGRIND:
+                daemon.cmd_line.append("--dev-no-backtrace")
         opts = [] if options is None else options
         for opt in opts:
             daemon.cmd_line.append(opt)