[PATCH xserver 1/2] os: Add poll emulation for mingw [v2]
Keith Packard
keithp at keithp.com
Mon Jul 18 23:28:18 UTC 2016
From: "Brian M. Clapper" <bmc at clapper.org>
v2: rename as 'xserver_poll' to avoid potential library name
collisions. Provide 'xserver_poll.h' which uses the system
poll where available and falls back to this emulation otherwise.
Autodetects when this is required, building the emulation only
then
Source: https://github.com/bmc/poll
Signed-off-by: Adam Jackson <ajax at redhat.com>
---
configure.ac | 3 +-
include/dix-config.h.in | 3 +
include/xserver_poll.h | 55 ++++++++++
os/Makefile.am | 7 ++
os/xserver_poll.c | 277 ++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 344 insertions(+), 1 deletion(-)
create mode 100644 include/xserver_poll.h
create mode 100644 os/xserver_poll.c
diff --git a/configure.ac b/configure.ac
index 52466d1..58fcf79 100644
--- a/configure.ac
+++ b/configure.ac
@@ -219,9 +219,10 @@ dnl Checks for library functions.
AC_CHECK_FUNCS([backtrace ffs geteuid getuid issetugid getresuid \
getdtablesize getifaddrs getpeereid getpeerucred getprogname getzoneid \
mmap posix_fallocate seteuid shmctl64 strncasecmp vasprintf vsnprintf \
- walkcontext setitimer])
+ walkcontext setitimer poll])
AC_CONFIG_LIBOBJ_DIR([os])
AC_REPLACE_FUNCS([reallocarray strcasecmp strcasestr strlcat strlcpy strndup])
+AM_CONDITIONAL(POLL, [test "x$ac_cv_func_poll" = "xyes"])
AC_CHECK_DECLS([program_invocation_short_name], [], [], [[#include <errno.h>]])
diff --git a/include/dix-config.h.in b/include/dix-config.h.in
index fc7d1a1..bf2a9ed 100644
--- a/include/dix-config.h.in
+++ b/include/dix-config.h.in
@@ -527,4 +527,7 @@
/* Use input thread */
#undef INPUTTHREAD
+/* Have poll() */
+#undef HAVE_POLL
+
#endif /* _DIX_CONFIG_H_ */
diff --git a/include/xserver_poll.h b/include/xserver_poll.h
new file mode 100644
index 0000000..110d30c
--- /dev/null
+++ b/include/xserver_poll.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright © 2016 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission. The copyright holders make no representations
+ * about the suitability of this software for any purpose. It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef _XSERVER_POLL_H_
+#define _XSERVER_POLL_H_
+
+#ifndef _DIX_CONFIG_H_
+#error must inclue dix-config.h to use xserver_poll.h
+#endif
+
+#if HAVE_POLL
+#include <poll.h>
+#define xserver_poll(fds, nfds, timeout) poll(fds, nfds, timeout)
+#else
+
+#define POLLIN 0x01
+#define POLLPRI 0x02
+#define POLLOUT 0x04
+#define POLLERR 0x08
+#define POLLHUP 0x10
+#define POLLNVAL 0x20
+
+struct pollfd
+{
+ int fd;
+ short events;
+ short revents;
+};
+
+typedef unsigned long nfds_t;
+
+int xserver_poll (struct pollfd *pArray, nfds_t n_fds, int timeout);
+
+#endif
+
+#endif /* _XSERVER_POLL_H_ */
diff --git a/os/Makefile.am b/os/Makefile.am
index fc49a73..c449076 100644
--- a/os/Makefile.am
+++ b/os/Makefile.am
@@ -7,6 +7,8 @@ XDMCP_SRCS = xdmcp.c
XORG_SRCS = log.c
BUSFAULT_SRCS = busfault.c
+XSERVER_POLL_SRCS=xserver_poll.c
+
libos_la_SOURCES = \
WaitFor.c \
access.c \
@@ -32,6 +34,11 @@ if SECURE_RPC
libos_la_SOURCES += $(SECURERPC_SRCS)
endif
+if POLL
+else
+libos_la_SOURCES += $(XSERVER_POLL_SRCS)
+endif
+
if XDMCP
libos_la_SOURCES += $(XDMCP_SRCS)
endif
diff --git a/os/xserver_poll.c b/os/xserver_poll.c
new file mode 100644
index 0000000..f152cda
--- /dev/null
+++ b/os/xserver_poll.c
@@ -0,0 +1,277 @@
+/*---------------------------------------------------------------------------*\
+ $Id$
+
+ NAME
+
+ poll - select(2)-based poll() emulation function for BSD systems.
+
+ SYNOPSIS
+ #include "poll.h"
+
+ struct pollfd
+ {
+ int fd;
+ short events;
+ short revents;
+ }
+
+ int poll (struct pollfd *pArray, unsigned long n_fds, int timeout)
+
+ DESCRIPTION
+
+ This file, and the accompanying "poll.h", implement the System V
+ poll(2) system call for BSD systems (which typically do not provide
+ poll()). Poll() provides a method for multiplexing input and output
+ on multiple open file descriptors; in traditional BSD systems, that
+ capability is provided by select(). While the semantics of select()
+ differ from those of poll(), poll() can be readily emulated in terms
+ of select() -- which is how this function is implemented.
+
+ REFERENCES
+ Stevens, W. Richard. Unix Network Programming. Prentice-Hall, 1990.
+
+ NOTES
+ 1. This software requires an ANSI C compiler.
+
+ LICENSE
+
+ This software is released under the following BSD license, adapted from
+ http://opensource.org/licenses/bsd-license.php
+
+ Copyright (c) 1995-2011, Brian M. Clapper
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+ this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ * Neither the name of the clapper.org nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+\*---------------------------------------------------------------------------*/
+
+
+/*---------------------------------------------------------------------------*\
+ Includes
+\*---------------------------------------------------------------------------*/
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <unistd.h> /* standard Unix definitions */
+#include <sys/types.h> /* system types */
+#include <sys/time.h> /* time definitions */
+#include <assert.h> /* assertion macros */
+#include <string.h> /* string functions */
+#include "xserver_poll.h"
+
+/*---------------------------------------------------------------------------*\
+ Macros
+\*---------------------------------------------------------------------------*/
+
+#ifndef MAX
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+
+/*---------------------------------------------------------------------------*\
+ Private Functions
+\*---------------------------------------------------------------------------*/
+
+static int map_poll_spec
+ (struct pollfd *pArray,
+ nfds_t n_fds,
+ fd_set *pReadSet,
+ fd_set *pWriteSet,
+ fd_set *pExceptSet)
+{
+ register nfds_t i; /* loop control */
+ register struct pollfd *pCur; /* current array element */
+ register int max_fd = -1; /* return value */
+
+ /*
+ Map the poll() structures into the file descriptor sets required
+ by select().
+ */
+ for (i = 0, pCur = pArray; i < n_fds; i++, pCur++)
+ {
+ /* Skip any bad FDs in the array. */
+
+ if (pCur->fd < 0)
+ continue;
+
+ if (pCur->events & POLLIN)
+ {
+ /* "Input Ready" notification desired. */
+ FD_SET (pCur->fd, pReadSet);
+ }
+
+ if (pCur->events & POLLOUT)
+ {
+ /* "Output Possible" notification desired. */
+ FD_SET (pCur->fd, pWriteSet);
+ }
+
+ if (pCur->events & POLLPRI)
+ {
+ /*
+ "Exception Occurred" notification desired. (Exceptions
+ include out of band data.
+ */
+ FD_SET (pCur->fd, pExceptSet);
+ }
+
+ max_fd = MAX (max_fd, pCur->fd);
+ }
+
+ return max_fd;
+}
+
+static struct timeval *map_timeout
+ (int poll_timeout, struct timeval *pSelTimeout)
+{
+ struct timeval *pResult;
+
+ /*
+ Map the poll() timeout value into a select() timeout. The possible
+ values of the poll() timeout value, and their meanings, are:
+
+ VALUE MEANING
+
+ -1 wait indefinitely (until signal occurs)
+ 0 return immediately, don't block
+ >0 wait specified number of milliseconds
+
+ select() uses a "struct timeval", which specifies the timeout in
+ seconds and microseconds, so the milliseconds value has to be mapped
+ accordingly.
+ */
+
+ assert (pSelTimeout != (struct timeval *) NULL);
+
+ switch (poll_timeout)
+ {
+ case -1:
+ /*
+ A NULL timeout structure tells select() to wait indefinitely.
+ */
+ pResult = (struct timeval *) NULL;
+ break;
+
+ case 0:
+ /*
+ "Return immediately" (test) is specified by all zeros in
+ a timeval structure.
+ */
+ pSelTimeout->tv_sec = 0;
+ pSelTimeout->tv_usec = 0;
+ pResult = pSelTimeout;
+ break;
+
+ default:
+ /* Wait the specified number of milliseconds. */
+ pSelTimeout->tv_sec = poll_timeout / 1000; /* get seconds */
+ poll_timeout %= 1000; /* remove seconds */
+ pSelTimeout->tv_usec = poll_timeout * 1000; /* get microseconds */
+ pResult = pSelTimeout;
+ break;
+ }
+
+
+ return pResult;
+}
+
+static void map_select_results
+ (struct pollfd *pArray,
+ unsigned long n_fds,
+ fd_set *pReadSet,
+ fd_set *pWriteSet,
+ fd_set *pExceptSet)
+{
+ register unsigned long i; /* loop control */
+ register struct pollfd *pCur; /* current array element */
+
+ for (i = 0, pCur = pArray; i < n_fds; i++, pCur++)
+ {
+ /* Skip any bad FDs in the array. */
+
+ if (pCur->fd < 0)
+ continue;
+
+ /* Exception events take priority over input events. */
+
+ pCur->revents = 0;
+ if (FD_ISSET (pCur->fd, pExceptSet))
+ pCur->revents |= POLLPRI;
+
+ else if (FD_ISSET (pCur->fd, pReadSet))
+ pCur->revents |= POLLIN;
+
+ if (FD_ISSET (pCur->fd, pWriteSet))
+ pCur->revents |= POLLOUT;
+ }
+
+ return;
+}
+
+/*---------------------------------------------------------------------------*\
+ Public Functions
+\*---------------------------------------------------------------------------*/
+
+int xserver_poll
+ (struct pollfd *pArray, unsigned long n_fds, int timeout)
+{
+ fd_set read_descs; /* input file descs */
+ fd_set write_descs; /* output file descs */
+ fd_set except_descs; /* exception descs */
+ struct timeval stime; /* select() timeout value */
+ int ready_descriptors; /* function result */
+ int max_fd; /* maximum fd value */
+ struct timeval *pTimeout; /* actually passed */
+
+ FD_ZERO (&read_descs);
+ FD_ZERO (&write_descs);
+ FD_ZERO (&except_descs);
+
+ assert (pArray != (struct pollfd *) NULL);
+
+ /* Map the poll() file descriptor list in the select() data structures. */
+
+ max_fd = map_poll_spec (pArray, n_fds,
+ &read_descs, &write_descs, &except_descs);
+
+ /* Map the poll() timeout value in the select() timeout structure. */
+
+ pTimeout = map_timeout (timeout, &stime);
+
+ /* Make the select() call. */
+
+ ready_descriptors = select (max_fd + 1, &read_descs, &write_descs,
+ &except_descs, pTimeout);
+
+ if (ready_descriptors >= 0)
+ {
+ map_select_results (pArray, n_fds,
+ &read_descs, &write_descs, &except_descs);
+ }
+
+ return ready_descriptors;
+}
--
2.8.1
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