diff --git a/usr.bin/truss/main.c b/usr.bin/truss/main.c
index d6a1edc..ade6c7b 100644
--- a/usr.bin/truss/main.c
+++ b/usr.bin/truss/main.c
@@ -163,6 +163,7 @@ strsig(int sig)
 int
 main(int ac, char **av)
 {
+	struct sigaction sa;
 	struct ex_types *funcs;
 	struct trussinfo *trussinfo;
 	char *fname;
@@ -257,10 +258,13 @@ main(int ac, char **av)
 		signal(SIGTERM, SIG_IGN);
 		signal(SIGQUIT, SIG_IGN);
 	} else {
+		sa.sa_handler = restore_proc;
+		sa.sa_flags = 0;
+		sigemptyset(&sa.sa_mask);
+		sigaction(SIGINT, &sa, NULL);
+		sigaction(SIGQUIT, &sa, NULL);
+		sigaction(SIGTERM, &sa, NULL);
 		start_tracing(trussinfo->pid);
-		signal(SIGINT, restore_proc);
-		signal(SIGTERM, restore_proc);
-		signal(SIGQUIT, restore_proc);
 	}
 
 
diff --git a/usr.bin/truss/setup.c b/usr.bin/truss/setup.c
index b4c61e1..2670355 100644
--- a/usr.bin/truss/setup.c
+++ b/usr.bin/truss/setup.c
@@ -58,6 +58,7 @@ __FBSDID("$FreeBSD$");
 #include "extern.h"
 
 static pid_t child_pid;
+static sig_atomic_t detaching;
 
 /*
  * setup_and_wait() is called to start a process.  All it really does
@@ -70,7 +71,6 @@ int
 setup_and_wait(char *command[])
 {
 	pid_t pid;
-	int waitval;
 
 	pid = vfork();
 	if (pid == -1)
@@ -82,10 +82,8 @@ setup_and_wait(char *command[])
 	}
 
 	/* Only in the parent here */
-	if (waitpid(pid, &waitval, 0) < 0) {
+	if (waitpid(pid, NULL, 0) < 0)
 		err(1, "unexpect stop in waitpid");
-		return 0;
-	}
 
 	child_pid = pid;
 
@@ -101,7 +99,7 @@ setup_and_wait(char *command[])
 int
 start_tracing(pid_t pid)
 {
-	int ret, retry, waitval;
+	int ret, retry;
 
 	retry = 10;
 	do {
@@ -112,7 +110,7 @@ start_tracing(pid_t pid)
 		err(1, "can not attach to target process");
 
 	child_pid = pid;
-	if (waitpid(pid, &waitval, 0) < 0)
+	if (waitpid(pid, NULL, 0) < 0)
 		err(1, "Unexpect stop in waitpid");
 
 	return (0);
@@ -127,12 +125,14 @@ start_tracing(pid_t pid)
 void
 restore_proc(int signo __unused)
 {
-	int waitval;
 
-	/* stop the child so that we can detach */
 	kill(child_pid, SIGSTOP);
-	if (waitpid(child_pid, &waitval, 0) < 0)
-		err(1, "Unexpected stop in waitpid");
+	detaching = 1;
+}
+
+static void
+detach_proc(void)
+{
 
 	if (ptrace(PT_DETACH, child_pid, (caddr_t)1, 0) < 0)
 		err(1, "Can not detach the process");
@@ -183,8 +183,15 @@ waitevent(struct trussinfo *info)
 	ptrace(PT_SYSCALL, info->pid, (caddr_t)1, pending_signal);
 	pending_signal = 0;
 
-	if (waitpid(info->pid, &waitval, 0) < 0)
+retry:
+	if (waitpid(info->pid, &waitval, 0) == -1) {
+		if (errno == EINTR)
+			goto retry;
 		err(1, "Unexpected stop in waitpid");
+	}
+
+	if (detaching)
+		detach_proc();
 
 	if (WIFCONTINUED(waitval)) {
 		info->pr_why = S_NONE;