/*

 * Copyright © 2012 Collabora, Ltd.

 *

 * 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.

 */

/*

 * This file is an adaptation of src/wayland-os.h from the wayland project and

 * shared/os-compatiblity.h from the weston project.

 *

 * Functions have been renamed just to prevent name clashes.

 */

#define _GNU_SOURCE

#if defined(__FreeBSD__) || defined(__DragonFly__)

#define USE_SHM

#endif

#include <sys/types.h>

#include <sys/socket.h>

#ifdef USE_SHM

#include <sys/mman.h>

#endif

#include <unistd.h>

#include <fcntl.h>

#include <errno.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <sys/epoll.h>

#include "../config.h"

#include "uwac-os.h"

static int set_cloexec_or_close(int fd)

{

	long flags;

	if (fd == -1)

		return -1;

	flags = fcntl(fd, F_GETFD);

	if (flags == -1)

		goto err;

	if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)

		goto err;

	return fd;

err:

	close(fd);

	return -1;

}

int uwac_os_socket_cloexec(int domain, int type, int protocol)

{

	int fd;

	fd = socket(domain, type | SOCK_CLOEXEC, protocol);

	if (fd >= 0)

		return fd;

	if (errno != EINVAL)

		return -1;

	fd = socket(domain, type, protocol);

	return set_cloexec_or_close(fd);

}

int uwac_os_dupfd_cloexec(int fd, long minfd)

{

	int newfd;

	newfd = fcntl(fd, F_DUPFD_CLOEXEC, minfd);

	if (newfd >= 0)

		return newfd;

	if (errno != EINVAL)

		return -1;

	newfd = fcntl(fd, F_DUPFD, minfd);

	return set_cloexec_or_close(newfd);

}

static ssize_t recvmsg_cloexec_fallback(int sockfd, struct msghdr* msg, int flags)

{

	ssize_t len;

	struct cmsghdr* cmsg;

	unsigned char* data;

	int* fd;

	int* end;

	len = recvmsg(sockfd, msg, flags);

	if (len == -1)

		return -1;

	if (!msg->msg_control || msg->msg_controllen == 0)

		return len;

	cmsg = CMSG_FIRSTHDR(msg);

	for (; cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg))

	{

		if (cmsg->cmsg_level != SOL_SOCKET ||

		    cmsg->cmsg_type != SCM_RIGHTS)

			continue;

		data = CMSG_DATA(cmsg);

		end = (int*)(data + cmsg->cmsg_len - CMSG_LEN(0));

		for (fd = (int*)data; fd < end; ++fd)

			*fd = set_cloexec_or_close(*fd);

	}

	return len;

}

ssize_t uwac_os_recvmsg_cloexec(int sockfd, struct msghdr* msg, int flags)

{

	ssize_t len;

	len = recvmsg(sockfd, msg, flags | MSG_CMSG_CLOEXEC);

	if (len >= 0)

		return len;

	if (errno != EINVAL)

		return -1;

	return recvmsg_cloexec_fallback(sockfd, msg, flags);

}

int uwac_os_epoll_create_cloexec(void)

{

	int fd;

#ifdef EPOLL_CLOEXEC

	fd = epoll_create1(EPOLL_CLOEXEC);

	if (fd >= 0)

		return fd;

	if (errno != EINVAL)

		return -1;

#endif

	fd = epoll_create(1);

	return set_cloexec_or_close(fd);

}

static int create_tmpfile_cloexec(char* tmpname)

{

	int fd;

#ifdef USE_SHM

	fd = shm_open(SHM_ANON, O_CREAT | O_RDWR, 0600);

#elif defined(HAVE_MKOSTEMP)

	fd = mkostemp(tmpname, O_CLOEXEC);

	if (fd >= 0)

		unlink(tmpname);

#else

	fd = mkstemp(tmpname);

	if (fd >= 0)

	{

		fd = set_cloexec_or_close(fd);

		unlink(tmpname);

	}

#endif

	return fd;

}

/*

 * Create a new, unique, anonymous file of the given size, and

 * return the file descriptor for it. The file descriptor is set

 * CLOEXEC. The file is immediately suitable for mmap()'ing

 * the given size at offset zero.

 *

 * The file should not have a permanent backing store like a disk,

 * but may have if XDG_RUNTIME_DIR is not properly implemented in OS.

 *

 * The file name is deleted from the file system.

 *

 * The file is suitable for buffer sharing between processes by

 * transmitting the file descriptor over Unix sockets using the

 * SCM_RIGHTS methods.

 *

 * If the C library implements posix_fallocate(), it is used to

 * guarantee that disk space is available for the file at the

 * given size. If disk space is insufficient, errno is set to ENOSPC.

 * If posix_fallocate() is not supported, program may receive

 * SIGBUS on accessing mmap()'ed file contents instead.

 */

int uwac_create_anonymous_file(off_t size)

{

	static const char template[] = "/weston-shared-XXXXXX";

	const char* path;

	char* name;

	int fd;

	int ret;

	size_t length;

	path = getenv("XDG_RUNTIME_DIR");

	if (!path)

	{

		errno = ENOENT;

		return -1;

	}

	length = strlen(path) + sizeof(template);

	name = malloc(length);

	if (!name)

		return -1;

	snprintf(name, length, "%s%s", path, template);

	fd = create_tmpfile_cloexec(name);

	free(name);

	if (fd < 0)

		return -1;

#ifdef HAVE_POSIX_FALLOCATE

	ret = posix_fallocate(fd, 0, size);

	if (ret != 0)

	{

		close(fd);

		errno = ret;

		return -1;

	}

#else

	ret = ftruncate(fd, size);

	if (ret < 0)

	{

		close(fd);

		return -1;

	}

#endif

	return fd;

}