1 files changed, 86 insertions, 0 deletions
diff --git a/src/util/timed_read.c b/src/util/timed_read.c
new file mode 100644
index 0000000..fdae8fa
--- /dev/null
+++ b/src/util/timed_read.c
@@ -0,0 +1,86 @@
+/*++
+/* NAME
+/*	timed_read 3
+/* SUMMARY
+/*	read operation with pre-read timeout
+/* SYNOPSIS
+/*	#include <iostuff.h>
+/*
+/*	ssize_t	timed_read(fd, buf, len, timeout, context)
+/*	int	fd;
+/*	void	*buf;
+/*	size_t	len;
+/*	int	timeout;
+/*	void	*context;
+/* DESCRIPTION
+/*	timed_read() performs a read() operation when the specified
+/*	descriptor becomes readable within a user-specified deadline.
+/*
+/*	Arguments:
+/* .IP fd
+/*	File descriptor in the range 0..FD_SETSIZE.
+/* .IP buf
+/*	Read buffer pointer.
+/* .IP len
+/*	Read buffer size.
+/* .IP timeout
+/*	The deadline in seconds. If this is <= 0, the deadline feature
+/*	is disabled.
+/* .IP context
+/*	Application context. This parameter is unused. It exists only
+/*	for the sake of VSTREAM compatibility.
+/* DIAGNOSTICS
+/*	When the operation does not complete within the deadline, the
+/*	result value is -1, and errno is set to ETIMEDOUT.
+/*	All other returns are identical to those of a read(2) operation.
+/* 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 <unistd.h>
+#include <errno.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <iostuff.h>
+
+/* timed_read - read with deadline */
+
+ssize_t timed_read(int fd, void *buf, size_t len,
+		           int timeout, void *unused_context)
+{
+    ssize_t ret;
+
+    /*
+     * Wait for a limited amount of time for something to happen. If nothing
+     * happens, report an ETIMEDOUT error.
+     * 
+     * XXX Solaris 8 read() fails with EAGAIN after read-select() returns
+     * success.
+     */
+    for (;;) {
+	if (timeout > 0 && read_wait(fd, timeout) < 0)
+	    return (-1);
+	if ((ret = read(fd, buf, len)) < 0 && timeout > 0 && errno == EAGAIN) {
+	    msg_warn("read() returns EAGAIN on a readable file descriptor!");
+	    msg_warn("pausing to avoid going into a tight select/read loop!");
+	    sleep(1);
+	    continue;
+	} else if (ret < 0 && errno == EINTR) {
+	    continue;
+	} else {
+	    return (ret);
+	}
+    }
+}