92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/*
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* Copyright (c) 2019 - 2020 Andri Yngvason
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <time.h>
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#include <unistd.h>
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#include "config.h"
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// Linux with glibc < 2.27 has no wrapper
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#if defined(HAVE_MEMFD) && !defined(HAVE_MEMFD_CREATE)
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#include <sys/syscall.h>
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static inline int memfd_create(const char *name, unsigned int flags) {
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return syscall(SYS_memfd_create, name, flags);
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}
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#endif
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#if !defined(HAVE_MEMFD) && !defined(__FreeBSD__)
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static void randname(char *buf)
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{
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struct timespec ts;
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clock_gettime(CLOCK_REALTIME, &ts);
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long r = ts.tv_nsec;
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for (int i = 0; i < 6; ++i) {
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buf[i] = 'A'+(r&15)+(r&16)*2;
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r >>= 5;
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}
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}
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#endif
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static int create_shm_file(void)
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{
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#ifdef HAVE_MEMFD
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return memfd_create("wayvnc-shm", 0);
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#elif defined(__FreeBSD__)
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// memfd_create added in FreeBSD 13, but SHM_ANON has been supported for ages
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return shm_open(SHM_ANON, O_RDWR | O_CREAT | O_EXCL, 0600);
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#else
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int retries = 100;
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do {
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char name[] = "/wl_shm-XXXXXX";
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randname(name + sizeof(name) - 7);
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--retries;
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int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
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if (fd >= 0) {
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shm_unlink(name);
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return fd;
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}
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} while (retries > 0 && errno == EEXIST);
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return -1;
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#endif
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}
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int shm_alloc_fd(size_t size)
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{
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int fd = create_shm_file();
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if (fd < 0)
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return -1;
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int ret;
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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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return fd;
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}
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