fix handling of returning value of ::waitpid() so that we clean up harvid correctly

diff --git a/gtk2_ardour/system_exec.cc b/gtk2_ardour/system_exec.cc
index ca059dada5e568786f94d317e2c64b9e4f1b0a8a..c63d1d183b2f6a4804b47d5e9f9a9625185a8486 100644 (file)
--- a/gtk2_ardour/system_exec.cc
+++ b/gtk2_ardour/system_exec.cc
@@ -414,6 +414,10 @@ void
 SystemExec::terminate ()
 {
        ::pthread_mutex_lock(&write_lock);
+
+       /* close stdin in an attempt to get the child to exit cleanly.
+        */
+
        close_stdin();
 
        if (pid) {
@@ -422,12 +426,21 @@ SystemExec::terminate ()
                wait(WNOHANG);
        }
 
+       /* if pid is non-zero, the child task is still executing (i.e. it did
+        * not exit in response to stdin being closed). try to kill it.
+        */
+       
        if (pid) {
                ::kill(pid, SIGTERM);
                ::usleep(50000);
                sched_yield();
                wait(WNOHANG);
        }
+
+       /* if pid is non-zero, the child task is STILL executing after being
+        * sent SIGTERM. Act tough ... send SIGKILL
+        */
+
        if (pid) {
                ::fprintf(stderr, "Process is still running! trying SIGKILL\n");
                ::kill(pid, SIGKILL);
@@ -443,15 +456,23 @@ int
 SystemExec::wait (int options)
 {
        int status=0;
+       int ret;
+
        if (pid==0) return -1;
-       if (pid==::waitpid(pid, &status, options)) {
+
+       ret = waitpid (pid, &status, options);
+
+       if (ret == pid) {
                if (WEXITSTATUS(status) || WIFSIGNALED(status)) {
                        pid=0;
                }
        } else {
-               if (errno == ECHILD) {
-                       pid=0;
-               }
+               if (ret != 0) {
+                       if (errno == ECHILD) {
+                               /* no currently running children, reset pid */
+                               pid=0;
+                       }
+               } /* else the process is still running */
        }
        return status;
 }
@@ -615,7 +636,7 @@ SystemExec::output_interposer()
        ssize_t r;
        unsigned long l = 1;
 
-  ioctl(rfd, FIONBIO, &l); // set non-blocking I/O
+       ioctl(rfd, FIONBIO, &l); // set non-blocking I/O
 
        for (;fcntl(rfd, F_GETFL)!=-1;) {
                r = read(rfd, buf, sizeof(buf));