prefer the use of references in private static function in system_exec.cc

[ardour.git] / gtk2_ardour / system_exec.cc

diff --git a/gtk2_ardour/system_exec.cc b/gtk2_ardour/system_exec.cc
index eb81c5fcb2158d040a11532561b2154d9b37f6a0..90c7294f5533fae89ad0ea37ec60e942818cf6a6 100644 (file)
--- a/gtk2_ardour/system_exec.cc
+++ b/gtk2_ardour/system_exec.cc
@@ -38,7 +38,7 @@
 using namespace std;
 void * interposer_thread (void *arg);
 
-static void close_fd (int* fd) { if (!fd) return; if (*fd >= 0) ::close (*fd); *fd = -1; }
+static void close_fd (int& fd) { if (fd >= 0) ::close (fd); fd = -1; }
 
 SystemExec::SystemExec (std::string c, std::string a)
        : cmd(c)
@@ -414,19 +414,33 @@ void
 SystemExec::terminate ()
 {
        ::pthread_mutex_lock(&write_lock);
+
+       /* close stdin in an attempt to get the child to exit cleanly.
+        */
+
        close_stdin();
+
        if (pid) {
                ::usleep(50000);
                sched_yield();
                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);
@@ -442,15 +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;
 }
@@ -488,18 +510,18 @@ SystemExec::start (int stderr_mode)
                pid=r;
 
                /* check if execve was successful. */
-               close_fd(&pok[1]);
+               close_fd(pok[1]);
                char buf;
                for ( ;; ) {
                        ssize_t n = ::read(pok[0], &buf, 1 );
                        if ( n==1 ) {
                                /* child process returned from execve */
                                pid=0;
-                               close_fd(&pok[0]);
-                               close_fd(&pin[1]);
-                               close_fd(&pin[0]);
-                               close_fd(&pout[1]);
-                               close_fd(&pout[0]);
+                               close_fd(pok[0]);
+                               close_fd(pin[1]);
+                               close_fd(pin[0]);
+                               close_fd(pout[1]);
+                               close_fd(pout[0]);
                                pin[1] = -1;
                                return -3;
                        } else if ( n==-1 ) {
@@ -508,7 +530,7 @@ SystemExec::start (int stderr_mode)
                        }
                        break;
                }
-               close_fd(&pok[0]);
+               close_fd(pok[0]);
                /* child started successfully */
 
 #if 0
@@ -524,17 +546,17 @@ SystemExec::start (int stderr_mode)
                }
                if (r == 0) {
                        /* 2nd child process - catch stdout */
-                       close_fd(&pin[1]);
-                       close_fd(&pout[1]);
+                       close_fd(pin[1]);
+                       close_fd(pout[1]);
                        output_interposer();
                        exit(0);
                }
-               close_fd(&pout[1]);
-               close_fd(&pin[0]);
-               close_fd(&pout[0]);
+               close_fd(pout[1]);
+               close_fd(pin[0]);
+               close_fd(pout[0]);
 #else /* use pthread */
-               close_fd(&pout[1]);
-               close_fd(&pin[0]);
+               close_fd(pout[1]);
+               close_fd(pin[0]);
                int rv = pthread_create(&thread_id_tt, NULL, interposer_thread, this);
 
                thread_active=true;
@@ -548,15 +570,15 @@ SystemExec::start (int stderr_mode)
        }
 
        /* child process - exec external process */
-       close_fd(&pok[0]);
+       close_fd(pok[0]);
        ::fcntl(pok[1], F_SETFD, FD_CLOEXEC);
 
-       close_fd(&pin[1]);
+       close_fd(pin[1]);
        if (pin[0] != STDIN_FILENO) {
          ::dup2(pin[0], STDIN_FILENO);
        }
-       close_fd(&pin[0]);
-       close_fd(&pout[0]);
+       close_fd(pin[0]);
+       close_fd(pout[0]);
        if (pout[1] != STDOUT_FILENO) {
                ::dup2(pout[1], STDOUT_FILENO);
        }
@@ -574,7 +596,7 @@ SystemExec::start (int stderr_mode)
        }
 
        if (pout[1] != STDOUT_FILENO && pout[1] != STDERR_FILENO) {
-               close_fd(&pout[1]);
+               close_fd(pout[1]);
        }
 
        if (nicelevel !=0) {
@@ -601,7 +623,7 @@ SystemExec::start (int stderr_mode)
        /* if we reach here something went wrong.. */
        char buf = 0;
        (void) ::write(pok[1], &buf, 1 );
-       close_fd(&pok[1]);
+       close_fd(pok[1]);
        exit(-1);
        return -1;
 }
@@ -614,7 +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));
@@ -636,17 +658,18 @@ void
 SystemExec::close_stdin()
 {
        if (pin[1]<0) return;
-       close_fd(&pin[0]);
-       close_fd(&pin[1]);
-       close_fd(&pout[0]);
-       close_fd(&pout[1]);
+       close_fd(pin[0]);
+       close_fd(pin[1]);
+       close_fd(pout[0]);
+       close_fd(pout[1]);
 }
 
 int
 SystemExec::write_to_stdin(std::string d, size_t len)
 {
        const char *data;
-       size_t r,c;
+       ssize_t r;
+       size_t c;
        ::pthread_mutex_lock(&write_lock);
 
        data=d.c_str();
@@ -661,7 +684,7 @@ SystemExec::write_to_stdin(std::string d, size_t len)
                                sleep(1);
                                continue;
                        }
-                       if (r != (len-c)) {
+                       if ((size_t) r != (len-c)) {
                                ::pthread_mutex_unlock(&write_lock);
                                return c;
                        }