Socat exited with status 0 even when a program invoked with SYSTEM or EXEC failed

CHANGES

@@ -22,6 +22,11 @@ corrections:
 	Test: EXEC_NOFORK_UNIDIR
 	Thanks to David Reiss for reporting this problem.
 
+	Socat exited with status 0 even when a program invoked with SYSTEM or
+	EXEC failed.
+	Tests: SYSTEM_RC EXEC_RC
+	Issue reported by Felix Winkelmann.
+
 porting:
 	Type conflict between int and sig_atomic_t between declaration and
 	definition of diag_immediate_type and diag_immediate_exit broke

test.sh

@@ -12205,7 +12205,8 @@ N=$((N+1))
 done
 
 
-# test if option fdout in write only context issues an error
+# Address options fdin and fdout were silently ignored when not applicable
+# due to -u or -U option. Now these combinations are caught as errors.
 NAME=FDOUT_ERROR
 case "$TESTS" in
 *%$N%*|*%functions%*|*%bugs%*|*%socket%*|*%$NAME%*)
@@ -12238,6 +12239,72 @@ PORT=$((PORT+1))
 N=$((N+1))
 
 
+# test if failure exit code of SYSTEM invocation causes socat to also exit
+# with !=0
+NAME=SYSTEM_RC
+case "$TESTS" in
+*%$N%*|*%functions%*|*%system%*|*%$NAME%*)
+TEST="$NAME: promote failure of SYSTEM"
+# run socat with SYSTEM:false and check if socat exits with !=0
+if ! eval $NUMCOND; then :; else
+tf="$td/test$N.stdout"
+te="$td/test$N.stderr"
+tdiff="$td/test$N.diff"
+da="test$N $(date) $RANDOM"
+CMD0="$TRACE $SOCAT $opts /dev/null SYSTEM:false"
+printf "test $F_n $TEST... " $N
+$CMD0 >/dev/null 2>"${te}0"
+rc0=$?
+if [ $rc0 -eq 0 ]; then
+    $PRINTF "$FAILED\n"
+    echo "$CMD0"
+    cat "${te}0"
+    numFAIL=$((numFAIL+1))
+    listFAIL="$listFAIL $N"
+else
+    $PRINTF "$OK\n"
+    numOK=$((numOK+1))
+fi
+fi # NUMCOND
+ ;;
+esac
+PORT=$((PORT+1))
+N=$((N+1))
+
+
+# test if failure exit code of EXEC invocation causes socat to also exit
+# with !=0
+NAME=EXEC_RC
+case "$TESTS" in
+*%$N%*|*%functions%*|*%exec%*|*%$NAME%*)
+TEST="$NAME: promote failure of EXEC"
+# run socat with EXEC:false and check if socat exits with !=0
+if ! eval $NUMCOND; then :; else
+tf="$td/test$N.stdout"
+te="$td/test$N.stderr"
+tdiff="$td/test$N.diff"
+da="test$N $(date) $RANDOM"
+CMD0="$TRACE $SOCAT $opts EXEC:false /dev/null"
+printf "test $F_n $TEST... " $N
+$CMD0 >/dev/null 2>"${te}0"
+rc0=$?
+if [ $rc0 -eq 0 ]; then
+    $PRINTF "$FAILED\n"
+    echo "$CMD0"
+    cat "${te}0"
+    numFAIL=$((numFAIL+1))
+    listFAIL="$listFAIL $N"
+else
+    $PRINTF "$OK\n"
+    numOK=$((numOK+1))
+fi
+fi # NUMCOND
+ ;;
+esac
+PORT=$((PORT+1))
+N=$((N+1))
+
+
 # test the so-reuseaddr option
 NAME=SO_REUSEADDR
 case "$TESTS" in

xio-system.c

@@ -61,12 +61,14 @@ static int xioopen_system(int argc, const char *argv[], struct opt *opts,
 	 Dup2(duptostderr, 2);
       }
       Info1("executing shell command \"%s\"", string);
+      errno=0;
       result = System(string);
       if (result != 0) {
 	 Warn2("system(\"%s\") returned with status %d", string, result);
+	 if (errno != 0)
 	    Warn1("system(): %s", strerror(errno));
       }
-      Exit(0);	/* this child process */
+      Exit(result>>8);	/* this child process */
    }
 
    /* parent */

xiosigchld.c

@@ -130,12 +130,22 @@ void childdied(int signum) {
 	 Info2("waitpid(): child %d exited with status %d",
 	       pid, WEXITSTATUS(status));
       } else {
-	 Warn2("waitpid(): child %d exited with status %d",
+	 if (i == XIO_MAXSOCK) {
+	    Info2("waitpid(): child %d exited with status %d",
+		   pid, WEXITSTATUS(status));
+	 } else {
+	    Error2("waitpid(): child %d exited with status %d",
 		   pid, WEXITSTATUS(status));
 	 }
+      }
    } else if (WIFSIGNALED(status)) {
+      if (i == XIO_MAXSOCK) {
 	 Info2("waitpid(): child %d exited on signal %d",
 	       pid, WTERMSIG(status));
+      } else {
+	 Error2("waitpid(): child %d exited on signal %d",
+	       pid, WTERMSIG(status));
+      }
    } else if (WIFSTOPPED(status)) {
       Info2("waitpid(): child %d stopped on signal %d",
 	    pid, WSTOPSIG(status));