2 files changed, 18 insertions, 3 deletions

diff --git a/usr.bin/truss/main.c b/usr.bin/truss/main.c
index ab5c0bae20dd..d09ee67dbadb 100644
--- a/usr.bin/truss/main.c
+++ b/usr.bin/truss/main.c
@@ -202,6 +202,9 @@ main(int ac, char **av) {
 
   Procfd = start_tracing(pid, S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT |
 		     (nosigs ? 0 : S_SIG));
+  if (Procfd == -1)
+    return 0;
+
   pfs.why = 0;
 
   funcs = set_etype();
@@ -251,8 +254,12 @@ main(int ac, char **av) {
 	break;
       }
     }
-    if (ioctl(Procfd, PIOCCONT, val) == -1)
-      warn("PIOCCONT");
+    if (ioctl(Procfd, PIOCCONT, val) == -1) {
+      if (kill(pid, 0) == -1 && errno == ESRCH)
+	break;
+      else
+	warn("PIOCCONT");
+    }
   } while (pfs.why != S_EXIT);
   fflush(outfile);
   if (sigexit) {
diff --git a/usr.bin/truss/setup.c b/usr.bin/truss/setup.c
index afa011308e93..5af1fabbf01d 100644
--- a/usr.bin/truss/setup.c
+++ b/usr.bin/truss/setup.c
@@ -133,8 +133,16 @@ start_tracing(int pid, int flags) {
   sprintf(buf, "/proc/%d/mem", pid);
 
   fd = open(buf, O_RDWR);
-  if (fd == -1)
+  if (fd == -1) {
+    /*
+     * The process may have run away before we could start -- this
+     * happens with SUGID programs.  So we need to see if it still
+     * exists before we complain bitterly.
+     */
+    if (kill(pid, 0) == -1)
+      return -1;
     err(8, "cannot open %s", buf);
+  }
 
   if (ioctl(fd, PIOCSTATUS, &tmp) == -1) {
     err(10, "cannot get procfs status struct");