Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 371 insertions, 0 deletions

diff --git a/src/util/nbbio.c b/src/util/nbbio.c
new file mode 100644
index 0000000..0f345ed
--- /dev/null
+++ b/src/util/nbbio.c
@@ -0,0 +1,371 @@
+/*++
+/* NAME
+/*	nbbio 3
+/* SUMMARY
+/*	non-blocking buffered I/O
+/* SYNOPSIS
+/*	#include <nbbio.h>
+/*
+/*	NBBIO	*nbbio_create(fd, bufsize, label, action, context)
+/*	int	fd;
+/*	ssize_t	bufsize;
+/*	const char *label;
+/*	void	(*action)(int event, void *context);
+/*	char	*context;
+/*
+/*	void	nbbio_free(np)
+/*	NBBIO	*np;
+/*
+/*	void	nbbio_enable_read(np, timeout)
+/*	NBBIO	*np;
+/*	int	timeout;
+/*
+/*	void	nbbio_enable_write(np, timeout)
+/*	NBBIO	*np;
+/*	int	timeout;
+/*
+/*	void	nbbio_disable_readwrite(np)
+/*	NBBIO	*np;
+/*
+/*	void	nbbio_slumber(np, timeout)
+/*	NBBIO	*np;
+/*	int	timeout;
+/*
+/*	int	NBBIO_ACTIVE_FLAGS(np)
+/*	NBBIO	*np;
+/*
+/*	int	NBBIO_ERROR_FLAGS(np)
+/*	NBBIO	*np;
+/*
+/*	const ssize_t NBBIO_BUFSIZE(np)
+/*	NBBIO	*np;
+/*
+/*	ssize_t	NBBIO_READ_PEND(np)
+/*	NBBIO	*np;
+/*
+/*	char	*NBBIO_READ_BUF(np)
+/*	NBBIO	*np;
+/*
+/*	const ssize_t NBBIO_WRITE_PEND(np)
+/*	NBBIO	*np;
+/*
+/*	char	*NBBIO_WRITE_BUF(np)
+/*	NBBIO	*np;
+/* DESCRIPTION
+/*	This module implements low-level support for event-driven
+/*	I/O on a full-duplex stream. Read/write events are handled
+/*	by pseudothreads that run under control by the events(5)
+/*	module.  After each I/O operation, the application is
+/*	notified via a call-back routine.
+/*
+/*	It is up to the call-back routine to turn on/off read/write
+/*	events as appropriate.  It is an error to leave read events
+/*	enabled for a buffer that is full, or to leave write events
+/*	enabled for a buffer that is empty.
+/*
+/*	nbbio_create() creates a pair of buffers of the named size
+/*	for the named stream. The label specifies the purpose of
+/*	the stream, and is used for diagnostic messages.  The
+/*	nbbio(3) event handler invokes the application call-back
+/*	routine with the current event type (EVENT_READ etc.) and
+/*	with the application-specified context.
+/*
+/*	nbbio_free() terminates any pseudothreads associated with
+/*	the named buffer pair, closes the stream, and destroys the
+/*	buffer pair.
+/*
+/*	nbbio_enable_read() enables a read pseudothread for the
+/*	named buffer pair.  It is an error to enable a read
+/*	pseudothread while the read buffer is full, or while a read
+/*	or write pseudothread is still enabled.
+/*
+/*	nbbio_enable_write() enables a write pseudothread for the
+/*	named buffer pair.  It is an error to enable a write
+/*	pseudothread while the write buffer is empty, or while a
+/*	read or write pseudothread is still enabled.
+/*
+/*	nbbio_disable_readwrite() disables any read/write pseudothreads
+/*	for the named buffer pair, including timeouts. To ensure
+/*	buffer liveness, use nbbio_slumber() instead of
+/*	nbbio_disable_readwrite().  It is no error to call this
+/*	function while no read/write pseudothread is enabled.
+/*
+/*	nbbio_slumber() disables any read/write pseudothreads for
+/*	the named buffer pair, but keeps the timer active to ensure
+/*	buffer liveness. It is no error to call this function while
+/*	no read/write pseudothread is enabled.
+/*
+/*	NBBIO_ERROR_FLAGS() returns the error flags for the named buffer
+/*	pair: zero or more of NBBIO_FLAG_EOF (read EOF), NBBIO_FLAG_ERROR
+/*	(read/write error) or NBBIO_FLAG_TIMEOUT (time limit
+/*	exceeded).
+/*
+/*	NBBIO_ACTIVE_FLAGS() returns the pseudothread flags for the
+/*	named buffer pair: NBBIO_FLAG_READ (read pseudothread is
+/*	active), NBBIO_FLAG_WRITE (write pseudothread is active),
+/*	or zero (no pseudothread is active).
+/*
+/*	NBBIO_WRITE_PEND() and NBBIO_WRITE_BUF() evaluate to the
+/*	number of to-be-written bytes and the write buffer for the
+/*	named buffer pair. NBBIO_WRITE_PEND() must be updated by
+/*	the application code that fills the write buffer; no more
+/*	than NBBIO_BUFSIZE() bytes may be filled.
+/*
+/*	NBBIO_READ_PEND() and NBBIO_READ_BUF() evaluate to the
+/*	number of unread bytes and the read buffer for the named
+/*	buffer pair. NBBIO_READ_PEND() and NBBIO_READ_BUF() must
+/*	be updated by the application code that drains the read
+/*	buffer.
+/* SEE ALSO
+/*	events(3) event manager
+/* DIAGNOSTICS
+/*	Panic: interface violation.
+/*
+/*	Fatal: out of memory.
+/* 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>
+#include <string.h>			/* memmove() */
+
+ /*
+  * Utility library.
+  */
+#include <mymalloc.h>
+#include <msg.h>
+#include <events.h>
+#include <nbbio.h>
+
+/* nbbio_event - non-blocking event handler */
+
+static void nbbio_event(int event, void *context)
+{
+    const char *myname = "nbbio_event";
+    NBBIO  *np = (NBBIO *) context;
+    ssize_t count;
+
+    switch (event) {
+
+	/*
+	 * Read data into the read buffer. Leave it up to the application to
+	 * drain the buffer until it is empty.
+	 */
+    case EVENT_READ:
+	if (np->read_pend == np->bufsize)
+	    msg_panic("%s: socket fd=%d: read buffer is full",
+		      myname, np->fd);
+	if (np->read_pend < 0 || np->read_pend > np->bufsize)
+	    msg_panic("%s: socket fd=%d: bad pending read count %ld",
+		      myname, np->fd, (long) np->read_pend);
+	count = read(np->fd, np->read_buf + np->read_pend,
+		     np->bufsize - np->read_pend);
+	if (count > 0) {
+	    np->read_pend += count;
+	    if (msg_verbose)
+		msg_info("%s: read %ld on %s fd=%d",
+			 myname, (long) count, np->label, np->fd);
+	} else if (count == 0) {
+	    np->flags |= NBBIO_FLAG_EOF;
+	    if (msg_verbose)
+		msg_info("%s: read EOF on %s fd=%d",
+			 myname, np->label, np->fd);
+	} else {
+	    if (errno == EAGAIN)
+		msg_warn("%s: read() returns EAGAIN on readable descriptor",
+			 myname);
+	    np->flags |= NBBIO_FLAG_ERROR;
+	    if (msg_verbose)
+		msg_info("%s: read %s fd=%d: %m", myname, np->label, np->fd);
+	}
+	break;
+
+	/*
+	 * Drain data from the output buffer.  Notify the application
+	 * whenever some bytes are written.
+	 * 
+	 * XXX Enforce a total time limit to ensure liveness when a hostile
+	 * receiver sets a very small TCP window size.
+	 */
+    case EVENT_WRITE:
+	if (np->write_pend == 0)
+	    msg_panic("%s: socket fd=%d: empty write buffer", myname, np->fd);
+	if (np->write_pend < 0 || np->write_pend > np->bufsize)
+	    msg_panic("%s: socket fd=%d: bad pending write count %ld",
+		      myname, np->fd, (long) np->write_pend);
+	count = write(np->fd, np->write_buf, np->write_pend);
+	if (count > 0) {
+	    np->write_pend -= count;
+	    if (np->write_pend > 0)
+		memmove(np->write_buf, np->write_buf + count, np->write_pend);
+	} else {
+	    if (errno == EAGAIN)
+		msg_warn("%s: write() returns EAGAIN on writable descriptor",
+			 myname);
+	    np->flags |= NBBIO_FLAG_ERROR;
+	    if (msg_verbose)
+		msg_info("%s: write %s fd=%d: %m", myname, np->label, np->fd);
+	}
+	break;
+
+	/*
+	 * Something bad happened.
+	 */
+    case EVENT_XCPT:
+	np->flags |= NBBIO_FLAG_ERROR;
+	if (msg_verbose)
+	    msg_info("%s: error on %s fd=%d: %m", myname, np->label, np->fd);
+	break;
+
+	/*
+	 * Something good didn't happen.
+	 */
+    case EVENT_TIME:
+	np->flags |= NBBIO_FLAG_TIMEOUT;
+	if (msg_verbose)
+	    msg_info("%s: %s timeout on %s fd=%d",
+		     myname, NBBIO_OP_NAME(np), np->label, np->fd);
+	break;
+
+    default:
+	msg_panic("%s: unknown event %d", myname, event);
+    }
+
+    /*
+     * Application notification. The application will check for any error
+     * flags, copy application data from or to our buffer pair, and decide
+     * what I/O happens next.
+     */
+    np->action(event, np->context);
+}
+
+/* nbbio_enable_read - enable reading from socket into buffer */
+
+void    nbbio_enable_read(NBBIO *np, int timeout)
+{
+    const char *myname = "nbbio_enable_read";
+
+    /*
+     * Sanity checks.
+     */
+    if (np->flags & NBBIO_MASK_ACTIVE)
+	msg_panic("%s: socket fd=%d is enabled for %s",
+		  myname, np->fd, NBBIO_OP_NAME(np));
+    if (timeout <= 0)
+	msg_panic("%s: socket fd=%d: bad timeout %d",
+		  myname, np->fd, timeout);
+    if (np->read_pend >= np->bufsize)
+	msg_panic("%s: socket fd=%d: read buffer is full",
+		  myname, np->fd);
+
+    /*
+     * Enable events.
+     */
+    event_enable_read(np->fd, nbbio_event, (void *) np);
+    event_request_timer(nbbio_event, (void *) np, timeout);
+    np->flags |= NBBIO_FLAG_READ;
+}
+
+/* nbbio_enable_write - enable writing from buffer to socket */
+
+void    nbbio_enable_write(NBBIO *np, int timeout)
+{
+    const char *myname = "nbbio_enable_write";
+
+    /*
+     * Sanity checks.
+     */
+    if (np->flags & NBBIO_MASK_ACTIVE)
+	msg_panic("%s: socket fd=%d is enabled for %s",
+		  myname, np->fd, NBBIO_OP_NAME(np));
+    if (timeout <= 0)
+	msg_panic("%s: socket fd=%d bad timeout %d",
+		  myname, np->fd, timeout);
+    if (np->write_pend <= 0)
+	msg_panic("%s: socket fd=%d: empty write buffer",
+		  myname, np->fd);
+
+    /*
+     * Enable events.
+     */
+    event_enable_write(np->fd, nbbio_event, (void *) np);
+    event_request_timer(nbbio_event, (void *) np, timeout);
+    np->flags |= NBBIO_FLAG_WRITE;
+}
+
+/* nbbio_disable_readwrite - disable read/write/timer events */
+
+void    nbbio_disable_readwrite(NBBIO *np)
+{
+    np->flags &= ~NBBIO_MASK_ACTIVE;
+    event_disable_readwrite(np->fd);
+    event_cancel_timer(nbbio_event, (void *) np);
+}
+
+/* nbbio_slumber - disable read/write events, keep timer */
+
+void    nbbio_slumber(NBBIO *np, int timeout)
+{
+    np->flags &= ~NBBIO_MASK_ACTIVE;
+    event_disable_readwrite(np->fd);
+    event_request_timer(nbbio_event, (void *) np, timeout);
+}
+
+/* nbbio_create - create socket buffer */
+
+NBBIO  *nbbio_create(int fd, ssize_t bufsize, const char *label,
+		             NBBIO_ACTION action, void *context)
+{
+    NBBIO  *np;
+
+    /*
+     * Sanity checks.
+     */
+    if (fd < 0)
+	msg_panic("nbbio_create: bad file descriptor: %d", fd);
+    if (bufsize <= 0)
+	msg_panic("nbbio_create: bad buffer size: %ld", (long) bufsize);
+
+    /*
+     * Create a new buffer pair.
+     */
+    np = (NBBIO *) mymalloc(sizeof(*np));
+    np->fd = fd;
+    np->bufsize = bufsize;
+    np->label = mystrdup(label);
+    np->action = action;
+    np->context = context;
+    np->flags = 0;
+
+    np->read_buf = mymalloc(bufsize);
+    np->read_pend = 0;
+
+    np->write_buf = mymalloc(bufsize);
+    np->write_pend = 0;
+
+    return (np);
+}
+
+/* nbbio_free - destroy socket buffer */
+
+void    nbbio_free(NBBIO *np)
+{
+    nbbio_disable_readwrite(np);
+    (void) close(np->fd);
+    myfree(np->label);
+    myfree(np->read_buf);
+    myfree(np->write_buf);
+    myfree((void *) np);
+}