1 files changed, 269 insertions, 0 deletions
diff --git a/src/util/poll_fd.c b/src/util/poll_fd.c
new file mode 100644
index 0000000..80cd0f6
--- /dev/null
+++ b/src/util/poll_fd.c
@@ -0,0 +1,269 @@
+/*++
+/* NAME
+/*	poll_fd 3
+/* SUMMARY
+/*	wait until file descriptor becomes readable or writable
+/* SYNOPSIS
+/*	#include <iostuff.h>
+/*
+/*	int	readable(fd)
+/*	int	fd;
+/*
+/*	int	writable(fd)
+/*	int	fd;
+/*
+/*	int	read_wait(fd, time_limit)
+/*	int	fd;
+/*	int	time_limit;
+/*
+/*	int	write_wait(fd, time_limit)
+/*	int	fd;
+/*	int	time_limit;
+/*
+/*	int	poll_fd(fd, request, time_limit, true_res, false_res)
+/*	int	fd;
+/*	int	request;
+/*	int	time_limit;
+/*	int	true_res;
+/*	int	false_res;
+/* DESCRIPTION
+/*	The read*() and write*() functions in this module are macros
+/*	that provide a convenient interface to poll_fd().
+/*
+/*	readable() asks the kernel if the specified file descriptor
+/*	is readable, i.e. a read operation would not block.
+/*
+/*	writable() asks the kernel if the specified file descriptor
+/*	is writable, i.e. a write operation would not block.
+/*
+/*	read_wait() waits until the specified file descriptor becomes
+/*	readable, or until the time limit is reached.
+/*
+/*	write_wait() waits until the specified file descriptor
+/*	becomes writable, or until the time limit is reached.
+/*
+/*	poll_fd() waits until the specified file descriptor becomes
+/*	readable or writable, or until the time limit is reached.
+/*
+/*	Arguments:
+/* .IP fd
+/*	File descriptor. With implementations based on select(), a
+/*	best effort is made to handle descriptors >=FD_SETSIZE.
+/* .IP request
+/*	POLL_FD_READ (wait until readable) or POLL_FD_WRITE (wait
+/*	until writable).
+/* .IP time_limit
+/*	A positive value specifies a time limit in seconds. A zero
+/*	value effects a poll (return immediately).  A negative value
+/*	means wait until the requested POLL_FD_READ or POLL_FD_WRITE
+/*	condition becomes true.
+/* .IP true_res
+/*	Result value when the requested POLL_FD_READ or POLL_FD_WRITE
+/*	condition is true.
+/* .IP false_res
+/*	Result value when the requested POLL_FD_READ or POLL_FD_WRITE
+/*	condition is false.
+/* DIAGNOSTICS
+/*	Panic: interface violation. All system call errors are fatal
+/*	unless specified otherwise.
+/*
+/*	readable() and writable() return 1 when the requested
+/*	POLL_FD_READ or POLL_FD_WRITE condition is true, zero when
+/*	it is false. They never return an error indication.
+/*
+/*	read_wait() and write_wait() return zero when the requested
+/*	POLL_FD_READ or POLL_FD_WRITE condition is true, -1 (with
+/*	errno set to ETIMEDOUT) when it is false.
+/*
+/*	poll_fd() returns true_res when the requested POLL_FD_READ
+/*	or POLL_FD_WRITE condition is true, false_res when it is
+/*	false.  When poll_fd() returns a false_res value < 0, it
+/*	also sets errno to ETIMEDOUT.
+/* 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/time.h>
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+ /*
+  * Use poll() with fall-back to select(). MacOSX needs this for devices.
+  */
+#if defined(USE_SYSV_POLL_THEN_SELECT)
+#define poll_fd_sysv	poll_fd
+#define USE_SYSV_POLL
+#define USE_BSD_SELECT
+int     poll_fd_bsd(int, int, int, int, int);
+
+ /*
+  * Use select() only.
+  */
+#elif defined(USE_BSD_SELECT)
+#define poll_fd_bsd	poll_fd
+#undef USE_SYSV_POLL
+
+ /*
+  * Use poll() only.
+  */
+#elif defined(USE_SYSV_POLL)
+#define poll_fd_sysv	poll_fd
+
+ /*
+  * Sanity check.
+  */
+#else
+#error "specify USE_SYSV_POLL, USE_BSD_SELECT or USE_SYSV_POLL_THEN_SELECT"
+#endif
+
+#ifdef USE_SYSV_POLL
+#include <poll.h>
+#endif
+
+#ifdef USE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <iostuff.h>
+
+#ifdef USE_BSD_SELECT
+
+/* poll_fd_bsd - block with time_limit until file descriptor is ready */
+
+int     poll_fd_bsd(int fd, int request, int time_limit,
+		            int true_res, int false_res)
+{
+    fd_set  req_fds;
+    fd_set *read_fds;
+    fd_set *write_fds;
+    fd_set  except_fds;
+    struct timeval tv;
+    struct timeval *tp;
+    int     temp_fd = -1;
+
+    /*
+     * Sanity checks.
+     */
+    if (FD_SETSIZE <= fd) {
+	if ((temp_fd = dup(fd)) < 0 || temp_fd >= FD_SETSIZE)
+	    msg_fatal("descriptor %d does not fit FD_SETSIZE %d", fd, FD_SETSIZE);
+	fd = temp_fd;
+    }
+
+    /*
+     * Use select() so we do not depend on alarm() and on signal() handlers.
+     * Restart select() when interrupted by some signal. Some select()
+     * implementations reduce the time to wait when interrupted, which is
+     * exactly what we want.
+     */
+    FD_ZERO(&req_fds);
+    FD_SET(fd, &req_fds);
+    except_fds = req_fds;
+    if (request == POLL_FD_READ) {
+	read_fds = &req_fds;
+	write_fds = 0;
+    } else if (request == POLL_FD_WRITE) {
+	read_fds = 0;
+	write_fds = &req_fds;
+    } else {
+	msg_panic("poll_fd: bad request %d", request);
+    }
+
+    if (time_limit >= 0) {
+	tv.tv_usec = 0;
+	tv.tv_sec = time_limit;
+	tp = &tv;
+    } else {
+	tp = 0;
+    }
+
+    for (;;) {
+	switch (select(fd + 1, read_fds, write_fds, &except_fds, tp)) {
+	case -1:
+	    if (errno != EINTR)
+		msg_fatal("select: %m");
+	    continue;
+	case 0:
+	    if (temp_fd != -1)
+		(void) close(temp_fd);
+	    if (false_res < 0)
+		errno = ETIMEDOUT;
+	    return (false_res);
+	default:
+	    if (temp_fd != -1)
+		(void) close(temp_fd);
+	    return (true_res);
+	}
+    }
+}
+
+#endif
+
+#ifdef USE_SYSV_POLL
+
+#ifdef USE_SYSV_POLL_THEN_SELECT
+#define HANDLE_SYSV_POLL_ERROR(fd, req, time_limit, true_res, false_res) \
+	return (poll_fd_bsd((fd), (req), (time_limit), (true_res), (false_res)))
+#else
+#define HANDLE_SYSV_POLL_ERROR(fd, req, time_limit, true_res, false_res) \
+	msg_fatal("poll: %m")
+#endif
+
+/* poll_fd_sysv - block with time_limit until file descriptor is ready */
+
+int     poll_fd_sysv(int fd, int request, int time_limit,
+		             int true_res, int false_res)
+{
+    struct pollfd pollfd;
+
+    /*
+     * System-V poll() is optimal for polling a few descriptors.
+     */
+#define WAIT_FOR_EVENT	(-1)
+
+    pollfd.fd = fd;
+    if (request == POLL_FD_READ) {
+	pollfd.events = POLLIN;
+    } else if (request == POLL_FD_WRITE) {
+	pollfd.events = POLLOUT;
+    } else {
+	msg_panic("poll_fd: bad request %d", request);
+    }
+
+    for (;;) {
+	switch (poll(&pollfd, 1, time_limit < 0 ?
+		     WAIT_FOR_EVENT : time_limit * 1000)) {
+	case -1:
+	    if (errno != EINTR)
+		HANDLE_SYSV_POLL_ERROR(fd, request, time_limit,
+				       true_res, false_res);
+	    continue;
+	case 0:
+	    if (false_res < 0)
+		errno = ETIMEDOUT;
+	    return (false_res);
+	default:
+	    if (pollfd.revents & POLLNVAL)
+		HANDLE_SYSV_POLL_ERROR(fd, request, time_limit,
+				       true_res, false_res);
+	    return (true_res);
+	}
+    }
+}
+
+#endif