Import first version of the library

Signed-off-by: Keith Packard <keithp@keithp.com>

8 files changed, 394 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
new file mode 100644
index 0000000..92503b3
--- /dev/null
+++ b/Makefile.am
@@ -0,0 +1,41 @@
+#
+# Copyright © 2013 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.
+#
+
+SUBDIRS = src
+
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = xshmfence.pc
+
+EXTRA_DIST = xshmfence.pc.in ChangeLog
+MAINTAINERCLEANFILES = ChangeLog
+
+.PHONY: ChangeLog
+
+ChangeLog:
+	$(CHANGELOG_CMD)
+
+dist-hook: ChangeLog
+
+if LINT
+lint:
+	(cd src && $(MAKE) $(MFLAGS) lint)
+endif LINT
diff --git a/autogen.sh b/autogen.sh
new file mode 100755
index 0000000..904cd67
--- /dev/null
+++ b/autogen.sh
@@ -0,0 +1,12 @@
+#! /bin/sh
+
+srcdir=`dirname $0`
+test -z "$srcdir" && srcdir=.
+
+ORIGDIR=`pwd`
+cd $srcdir
+
+autoreconf -v --install || exit 1
+cd $ORIGDIR || exit $?
+
+$srcdir/configure --enable-maintainer-mode "$@"
diff --git a/configure.ac b/configure.ac
new file mode 100644
index 0000000..555fdd6
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,50 @@
+dnl
+dnl Copyright © 2013 Keith Packard
+dnl
+dnl Permission to use, copy, modify, distribute, and sell this software and its
+dnl documentation for any purpose is hereby granted without fee, provided that
+dnl the above copyright notice appear in all copies and that both that copyright
+dnl notice and this permission notice appear in supporting documentation, and
+dnl that the name of the copyright holders not be used in advertising or
+dnl publicity pertaining to distribution of the software without specific,
+dnl written prior permission.  The copyright holders make no representations
+dnl about the suitability of this software for any purpose.  It is provided "as
+dnl is" without express or implied warranty.
+dnl
+dnl THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+dnl INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+dnl EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+dnl CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+dnl DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+dnl TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+dnl OF THIS SOFTWARE.
+dnl
+dnl
+dnl Process this file with autoconf to create configure.
+
+AC_PREREQ([2.57])
+
+AC_INIT(libxshmfence, 0.1, [https://bugs.freedesktop.org/enter_bug.cgi?product=xorg], libxshmfence)
+AM_INIT_AUTOMAKE([dist-bzip2 foreign])
+AM_MAINTAINER_MODE
+
+# Require xorg-macros: XORG_CWARNFLAGS, XORG_CHANGELOG, XORG_WITH_LINT
+m4_ifndef([XORG_MACROS_VERSION], [AC_FATAL([must install xorg-macros 1.2 or later before running autoconf/autogen])])
+XORG_MACROS_VERSION(1.2)
+AM_CONFIG_HEADER(config.h)
+
+# Check for progs
+AC_PROG_CC
+AC_PROG_LIBTOOL
+XORG_CWARNFLAGS
+
+dnl Allow checking code with lint, sparse, etc.
+XORG_WITH_LINT
+LINT_FLAGS="${LINT_FLAGS} ${FONTENC_CFLAGS}"
+		  
+XORG_RELEASE_VERSION
+XORG_CHANGELOG
+
+AC_OUTPUT([Makefile
+	   src/Makefile
+           xshmfence.pc])
diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..90d7bcb
--- /dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,19 @@
+lib_LTLIBRARIES = libxshmfence.la
+
+libxshmfence_la_SOURCES = \
+        xshmfence.c
+
+noinst_HEADERS = xshmfenceint.h
+
+libxshmfence_la_LDFLAGS = -version-number 1:0:0 -no-undefined
+
+libxshmfenceincludedir = $(includedir)/X11
+libxshmfenceinclude_HEADERS = xshmfence.h
+
+if LINT
+ALL_LINT_FLAGS=$(LINT_FLAGS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \
+		$(AM_CPPFLAGS) $(CPPFLAGS)
+
+lint:
+	$(LINT) $(ALL_LINT_FLAGS) $(libxshmfence_la_SOURCES) $(libxshmfence_la_LIBADD) $(LIBS)
+endif LINT
diff --git a/src/xshmfence.c b/src/xshmfence.c
new file mode 100644
index 0000000..521d3ad
--- /dev/null
+++ b/src/xshmfence.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright © 2013 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.
+ */
+
+#include "xshmfenceint.h"
+
+/**
+ * xshmfence_trigger:
+ * @f: An X fence
+ *
+ * Set @f to triggered, waking all waiters.
+ *
+ * Return value: 0 on success and -1 on error (in which case, errno
+ * will be set as appropriate).
+ **/
+int
+xshmfence_trigger(int32_t *f)
+{
+	if (__sync_val_compare_and_swap(f, 0, 1) == -1) {
+		atomic_store(f, 1);
+		if (futex_wake(f) < 0)
+			return -1;
+	}
+	return 0;
+}
+
+/**
+ * xshmfence_await:
+ * @f: An X fence
+ *
+ * Wait for @f to be triggered. If @f is already triggered, this
+ * function returns immediately.
+ *
+ * Return value: 0 on success and -1 on error (in which case, errno
+ * will be set as appropriate).
+ **/
+int
+xshmfence_await(int32_t *f)
+{
+	while (__sync_val_compare_and_swap(f, 0, -1) != 1) {
+		if (futex_wait(f, -1)) {
+			if (errno != EWOULDBLOCK)
+				return -1;
+		}
+	}
+	return 0;
+}
+
+/**
+ * xshmfence_query:
+ * @f: An X fence
+ *
+ * Return value: 1 if @f is triggered, else returns 0.
+ **/
+int
+xshmfence_query(int32_t *f)
+{
+	return atomic_fetch(f) == 1;
+}
+
+/**
+ * xshmfence_reset:
+ * @f: An X fence
+ *
+ * Reset @f to untriggered. If @f is already untriggered,
+ * this function has no effect.
+ **/
+void
+xshmfence_reset(int32_t *f)
+{
+	__sync_bool_compare_and_swap(f, 1, 0);
+}
+
+
+/**
+ * xshmfence_alloc_shm:
+ *
+ * Allocates a shared memory object large enough to hold a single
+ * fence.
+ *
+ * Return value: the file descriptor of the object, or -1 on failure
+ * (in which case, errno will be set as appropriate).
+ **/
+int
+xshmfence_alloc_shm(void)
+{
+	char	template[] = "/run/shm/shmfd-XXXXXX";
+	int	fd = mkstemp(template);
+
+	if (fd < 0)
+		return fd;
+	unlink(template);
+	ftruncate(fd, sizeof (int32_t));
+	return fd;
+}
+
+/**
+ * xshmfence_map_shm:
+ *
+ * Map a shared memory fence referenced by @fd.
+ *
+ * Return value: the fence or NULL (in which case, errno will be set
+ * as appropriate).
+ **/
+int32_t *
+xshmfence_map_shm(int fd)
+{
+	void *addr;
+	addr = mmap (NULL, sizeof (int32_t) , PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		close (fd);
+		return 0;
+	}
+	return addr;
+}
+
+/**
+ * xshmfence_unmap_shm:
+ *
+ * Unap a shared memory fence @f.
+ **/
+void
+xshmfence_unmap_shm(int32_t *f)
+{
+        munmap(f, sizeof (int32_t));
+}
diff --git a/src/xshmfence.h b/src/xshmfence.h
new file mode 100644
index 0000000..f3cbad9
--- /dev/null
+++ b/src/xshmfence.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2013 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 _XSHMFENCE_H_
+#define _XSHMFENCE_H_
+
+#include <stdint.h>
+
+int
+xshmfence_trigger(int32_t *f);
+
+int
+xshmfence_await(int32_t *f);
+
+int
+xshmfence_query(int32_t *f);
+
+void
+xshmfence_reset(int32_t *f);
+
+int
+xshmfence_alloc_shm(void);
+
+int32_t *
+xshmfence_map_shm(int fd);
+
+void
+xshmfence_unmap_shm(int32_t *f);
+
+#endif /* _XSHMFENCE_H_ */
diff --git a/src/xshmfenceint.h b/src/xshmfenceint.h
new file mode 100644
index 0000000..3f5c561
--- /dev/null
+++ b/src/xshmfenceint.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2013 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 _XSHMFENCEINT_H_
+#define _XSHMFENCEINT_H_
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <linux/futex.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <values.h>
+
+static inline long sys_futex(void *addr1, int op, int val1, struct timespec *timeout, void *addr2, int val3)
+{
+	return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
+}
+
+static inline int futex_wake(int32_t *addr) {
+	return sys_futex(addr, FUTEX_WAKE, MAXINT, NULL, NULL, 0);
+}
+
+static inline int futex_wait(int32_t *addr, int32_t value) {
+	return sys_futex(addr, FUTEX_WAIT, value, NULL, NULL, 0);
+}
+
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+static inline void atomic_store(int32_t *f, int32_t v)
+{
+	barrier();
+	*f = v;
+	barrier();
+}
+
+static inline int32_t atomic_fetch(int32_t *a)
+{
+	int32_t v;
+	barrier();
+	v = *a;
+	barrier();
+	return v;
+}
+	
+#endif /* _XSHMFENCEINT_H_ */
diff --git a/xshmfence.pc.in b/xshmfence.pc.in
new file mode 100644
index 0000000..cfc1860
--- /dev/null
+++ b/xshmfence.pc.in
@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: xshmfence
+Description: The X Shared Memory Fence Library
+Version: @PACKAGE_VERSION@
+Cflags: -I${includedir}
+Libs: -L${libdir} -lxshmfence