1 files changed, 122 insertions, 0 deletions
diff --git a/src/util/timed_wait.c b/src/util/timed_wait.c
new file mode 100644
index 0000000..45fbb69
--- /dev/null
+++ b/src/util/timed_wait.c
@@ -0,0 +1,122 @@
+/*++
+/* NAME
+/*	timed_wait 3
+/* SUMMARY
+/*	wait operations with timeout
+/* SYNOPSIS
+/*	#include <timed_wait.h>
+/*
+/*	int	timed_waitpid(pid, statusp, options, time_limit)
+/*	pid_t	pid;
+/*	WAIT_STATUS_T *statusp;
+/*	int	options;
+/*	int	time_limit;
+/* DESCRIPTION
+/*	\fItimed_waitpid\fR() waits at most \fItime_limit\fR seconds
+/*	for process termination.
+/*
+/*	Arguments:
+/* .IP "pid, statusp, options"
+/*	The process ID, status pointer and options passed to waitpid(3).
+/* .IP time_limit
+/*	The time in seconds that timed_waitpid() will wait.
+/*	This must be a number > 0.
+/* DIAGNOSTICS
+/*	Panic: interface violation.
+/*
+/*	When the time limit is exceeded, the result is -1 and errno
+/*	is set to ETIMEDOUT. Otherwise, the result value is the result
+/*	from the underlying waitpid() routine.
+/* BUGS
+/*	If there were a \fIportable\fR way to select() on process status
+/*	information, these routines would not have to use a steenkeeng
+/*	alarm() timer and signal() handler.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <posix_signals.h>
+#include <timed_wait.h>
+
+/* Application-specific. */
+
+static int timed_wait_expired;
+
+/* timed_wait_alarm - timeout handler */
+
+static void timed_wait_alarm(int unused_sig)
+{
+
+    /*
+     * WARNING WARNING WARNING.
+     * 
+     * This code runs at unpredictable moments, as a signal handler. This code
+     * is here only so that we can break out of waitpid(). Don't put any code
+     * here other than for setting a global flag.
+     */
+    timed_wait_expired = 1;
+}
+
+/* timed_waitpid - waitpid with time limit */
+
+int     timed_waitpid(pid_t pid, WAIT_STATUS_T *statusp, int options,
+		              int time_limit)
+{
+    const char *myname = "timed_waitpid";
+    struct sigaction action;
+    struct sigaction old_action;
+    int     time_left;
+    int     wpid;
+
+    /*
+     * Sanity checks.
+     */
+    if (time_limit <= 0)
+	msg_panic("%s: bad time limit: %d", myname, time_limit);
+
+    /*
+     * Set up a timer.
+     */
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+    action.sa_handler = timed_wait_alarm;
+    if (sigaction(SIGALRM, &action, &old_action) < 0)
+	msg_fatal("%s: sigaction(SIGALRM): %m", myname);
+    timed_wait_expired = 0;
+    time_left = alarm(time_limit);
+
+    /*
+     * Wait for only a limited amount of time.
+     */
+    if ((wpid = waitpid(pid, statusp, options)) < 0 && timed_wait_expired)
+	errno = ETIMEDOUT;
+
+    /*
+     * Cleanup.
+     */
+    alarm(0);
+    if (sigaction(SIGALRM, &old_action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction(SIGALRM): %m", myname);
+    if (time_left)
+	alarm(time_left);
+
+    return (wpid);
+}