wlroots-hyprland/util/os-compatibility.c

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/*
* Copyright © 2012 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
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#define _POSIX_C_SOURCE 200809L
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
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#include <sys/types.h>
#include <unistd.h>
#include <wlr/config.h>
#include "util/os-compatibility.h"
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int os_fd_set_cloexec(int fd) {
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if (fd == -1) {
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return -1;
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}
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long flags = fcntl(fd, F_GETFD);
if (flags == -1) {
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return -1;
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}
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if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) {
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return -1;
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}
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return 0;
}
int set_cloexec_or_close(int fd) {
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if (os_fd_set_cloexec(fd) != 0) {
close(fd);
return -1;
}
return fd;
}
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int create_tmpfile_cloexec(char *tmpname) {
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int fd;
mode_t prev_umask = umask(0066);
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#ifdef HAVE_MKOSTEMP
fd = mkostemp(tmpname, O_CLOEXEC);
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if (fd >= 0) {
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unlink(tmpname);
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}
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#else
fd = mkstemp(tmpname);
if (fd >= 0) {
fd = set_cloexec_or_close(fd);
unlink(tmpname);
}
#endif
umask(prev_umask);
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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 os_create_anonymous_file(off_t size) {
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static const char template[] = "/wlroots-shared-XXXXXX";
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const char *path = getenv("XDG_RUNTIME_DIR");
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if (!path) {
errno = ENOENT;
return -1;
}
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char *name = malloc(strlen(path) + sizeof(template));
if (!name) {
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return -1;
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}
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strcpy(name, path);
strcat(name, template);
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int 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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}
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#ifdef WLR_HAS_POSIX_FALLOCATE
int ret;
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do {
ret = posix_fallocate(fd, 0, size);
} while (ret == EINTR);
if (ret != 0) {
close(fd);
errno = ret;
return -1;
}
#else
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int ret;
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do {
ret = ftruncate(fd, size);
} while (ret < 0 && errno == EINTR);
if (ret < 0) {
close(fd);
return -1;
}
#endif
return fd;
}