X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=signal.c;h=cc49da11f2b647c83cb068b0cecab439419eb571;hp=bf0cd5ccff28286852858e1b4f22bf00f9436f7b;hb=50eb5f37e3da3036fb709cd7ab2825c8d827f42a;hpb=3689799ede7bba230ca544ac953392b428c3d662

diff --git a/signal.c b/signal.c
index bf0cd5cc..cc49da11 100644
--- a/signal.c
+++ b/signal.c
@@ -16,7 +16,7 @@
 static int signal_pipe[2];
 
 /**
- * initialize the paraslash signal subsystem
+ * Initialize the paraslash signal subsystem.
  *
  * This function creates a pipe, the signal pipe, to deliver pending
  * signals to the application (Bernstein's trick). It should be called
@@ -35,13 +35,15 @@ static int signal_pipe[2];
  */
 int para_signal_init(void)
 {
-	int ret = -E_SIGNAL_PIPE;
-	if (pipe(signal_pipe))
+	int ret;
+	if (pipe(signal_pipe) < 0) {
+		ret = -ERRNO_TO_PARA_ERROR(errno);
 		goto err_out;
-	ret = mark_fd_nonblock(signal_pipe[0]);
+	}
+	ret = mark_fd_nonblocking(signal_pipe[0]);
 	if (ret < 0)
 		goto err_out;
-	ret = mark_fd_nonblock(signal_pipe[1]);
+	ret = mark_fd_nonblocking(signal_pipe[1]);
 	if (ret < 0)
 		goto err_out;
 	return signal_pipe[0];
@@ -60,45 +62,50 @@ static void generic_signal_handler(int s)
 }
 
 /**
- * reap one child
+ * Reap one child.
+ *
+ * \param pid In case a child died, its pid is returned here.
+ *
+ * Call waitpid() and print a log message containing the pid and the cause of
+ * the child's death.
  *
- * call waitpid() and print a log message containing the pid
- * and the cause of the child's death.
+ * \return A (negative) paraslash error code on errors, zero, if no child died,
+ * one otherwise. If and only if the function returns one, the content of \a
+ * pid is meaningful.
  *
- * \return Like \p waitpid(), this function returns the process ID of the
- * terminated child; on error, \p -E_WAITPID is returned.
  * \sa waitpid(2)
  */
-pid_t para_reap_child(void)
+int para_reap_child(pid_t *pid)
 {
 	int status;
-	pid_t pid = waitpid(-1, &status, WNOHANG);
+	*pid = waitpid(-1, &status, WNOHANG);
 
-	if (pid <= 0) {
-		if (pid < 0)
-			pid = -E_WAITPID;
-		return pid;
-	}
+	if (!*pid)
+		return 0;
+	if (*pid < 0)
+		return -ERRNO_TO_PARA_ERROR(errno);
 	if (WIFEXITED(status))
-		PARA_DEBUG_LOG("child %i exited. Exit status: %i\n", pid,
+		PARA_DEBUG_LOG("child %i exited. Exit status: %i\n", (int)*pid,
 			WEXITSTATUS(status));
 	else if (WIFSIGNALED(status))
-		PARA_DEBUG_LOG("child %i was killed by signal %i\n", pid,
+		PARA_DEBUG_LOG("child %i was killed by signal %i\n", (int)*pid,
 			WTERMSIG(status));
 	else
-		PARA_WARNING_LOG("child %i terminated abormally\n", pid);
-	return pid;
+		PARA_WARNING_LOG("child %i terminated abormally\n", (int)*pid);
+	return 1;
 }
 
 /**
- * paraslash's zombie killer
+ * Paraslash's zombie killer.
  *
  * It just calls \p para_reap_child() until there are no more children left to
  * reap.
  */
 void para_reap_children(void)
 {
-	while (para_reap_child() > 0)
+	pid_t pid;
+
+	while (para_reap_child(&pid) > 0)
 		; /* nothing */
 }
 
@@ -122,7 +129,7 @@ int para_install_sighandler(int sig)
  * This should be called if the fd for the signal pipe is ready for reading.
  *
  * \return On success, the number of the received signal is returned. \p
- * -E_SIGNAL_READ is returned if a read error occured while reading the signal
+ * -E_SIGNAL_READ is returned if a read error occurred while reading the signal
  * pipe.  If the read was interrupted by another signal the function returns 0.
  */
 int para_next_signal(void)
@@ -130,9 +137,18 @@ int para_next_signal(void)
 	int s;
 	ssize_t r;
 
-	if ((r = read(signal_pipe[0], &s, sizeof(s)) == sizeof(s)) > 0) {
+	r = read(signal_pipe[0], &s, sizeof(s));
+	if (r == sizeof(s)) {
 		PARA_DEBUG_LOG("next signal: %d\n", s);
 		return s;
 	}
 	return r < 0 && (errno != EAGAIN)? 0 : -E_SIGNAL_READ;
 }
+
+/**
+ * Close the signal pipe.
+ */
+void para_signal_shutdown(void)
+{
+	close(signal_pipe[1]);
+}