nyorain
8 years ago
committed by
Drew DeVault
parent
53052b3f6e
commit
d7dcbbc175
@ -0,0 +1,154 @@
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/*
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* Copyright © 2012 Collabora, Ltd.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial
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* portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#define _XOPEN_SOURCE 700
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <sys/epoll.h>
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#include <string.h>
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#include <stdlib.h>
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int
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os_fd_set_cloexec(int fd)
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{
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long flags;
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if (fd == -1)
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return -1;
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flags = fcntl(fd, F_GETFD);
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if (flags == -1)
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return -1;
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if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
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return -1;
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return 0;
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}
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static int
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set_cloexec_or_close(int fd)
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{
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if (os_fd_set_cloexec(fd) != 0) {
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close(fd);
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return -1;
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}
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return fd;
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}
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static int
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create_tmpfile_cloexec(char *tmpname)
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{
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int fd;
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#ifdef HAVE_MKOSTEMP
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fd = mkostemp(tmpname, O_CLOEXEC);
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if (fd >= 0)
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unlink(tmpname);
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#else
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fd = mkstemp(tmpname);
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if (fd >= 0) {
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fd = set_cloexec_or_close(fd);
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unlink(tmpname);
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}
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#endif
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return fd;
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}
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/*
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* Create a new, unique, anonymous file of the given size, and
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* return the file descriptor for it. The file descriptor is set
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* CLOEXEC. The file is immediately suitable for mmap()'ing
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* the given size at offset zero.
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*
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* The file should not have a permanent backing store like a disk,
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* but may have if XDG_RUNTIME_DIR is not properly implemented in OS.
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*
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* The file name is deleted from the file system.
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*
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* The file is suitable for buffer sharing between processes by
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* transmitting the file descriptor over Unix sockets using the
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* SCM_RIGHTS methods.
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*
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* If the C library implements posix_fallocate(), it is used to
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* guarantee that disk space is available for the file at the
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* given size. If disk space is insufficient, errno is set to ENOSPC.
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* If posix_fallocate() is not supported, program may receive
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* SIGBUS on accessing mmap()'ed file contents instead.
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*/
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int
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os_create_anonymous_file(off_t size)
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{
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static const char template[] = "/wlroots-shared-XXXXXX";
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const char *path;
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char *name;
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int fd;
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int ret;
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path = getenv("XDG_RUNTIME_DIR");
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if (!path) {
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errno = ENOENT;
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return -1;
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}
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name = malloc(strlen(path) + sizeof(template));
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if (!name)
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return -1;
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strcpy(name, path);
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strcat(name, template);
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fd = create_tmpfile_cloexec(name);
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free(name);
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if (fd < 0)
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return -1;
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#ifdef HAVE_POSIX_FALLOCATE
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do {
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ret = posix_fallocate(fd, 0, size);
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} while (ret == EINTR);
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if (ret != 0) {
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close(fd);
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errno = ret;
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return -1;
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}
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#else
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do {
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ret = ftruncate(fd, size);
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} while (ret < 0 && errno == EINTR);
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if (ret < 0) {
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close(fd);
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return -1;
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}
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#endif
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return fd;
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}
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