mirror of
https://gitlab.freedesktop.org/wlroots/wlroots.git
synced 2024-11-22 15:12:26 +00:00
842093bb84
Stop trying to maintain a per-file _POSIX_C_SOURCE. Instead, require POSIX.1-2008 globally. A lot of core source files depend on that already. Some care must be taken on a few select files where we need a bit more than POSIX. Some files need XSI extensions (_XOPEN_SOURCE) and some files need BSD extensions (_DEFAULT_SOURCE). In both cases, these feature test macros imply _POSIX_C_SOURCE. Make sure to not define both these macros and _POSIX_C_SOURCE explicitly to avoid POSIX requirement conflicts (e.g. _POSIX_C_SOURCE says POSIX.1-2001 but _XOPEN_SOURCE says POSIX.1-2008). Additionally, there is one special case in render/vulkan/vulkan.c. That file needs major()/minor(), and these are system-specific. On FreeBSD, _POSIX_C_SOURCE hides system-specific symbols so we need to make sure it's not defined for this file. On Linux, we can explicitly include <sys/sysmacros.h> and ensure that apart from symbols defined there the file only uses POSIX toys.
98 lines
1.8 KiB
C
98 lines
1.8 KiB
C
#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <time.h>
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#include <unistd.h>
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#include <wlr/config.h>
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#include "util/shm.h"
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#define RANDNAME_PATTERN "/wlroots-XXXXXX"
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static void randname(char *buf) {
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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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static int excl_shm_open(char *name) {
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int retries = 100;
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do {
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randname(name + strlen(RANDNAME_PATTERN) - 6);
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--retries;
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// CLOEXEC is guaranteed to be set by shm_open
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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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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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}
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int allocate_shm_file(size_t size) {
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char name[] = RANDNAME_PATTERN;
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int fd = excl_shm_open(name);
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if (fd < 0) {
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return -1;
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}
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shm_unlink(name);
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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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bool allocate_shm_file_pair(size_t size, int *rw_fd_ptr, int *ro_fd_ptr) {
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char name[] = RANDNAME_PATTERN;
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int rw_fd = excl_shm_open(name);
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if (rw_fd < 0) {
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return false;
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}
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// CLOEXEC is guaranteed to be set by shm_open
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int ro_fd = shm_open(name, O_RDONLY, 0);
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if (ro_fd < 0) {
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shm_unlink(name);
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close(rw_fd);
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return false;
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}
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shm_unlink(name);
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// Make sure the file cannot be re-opened in read-write mode (e.g. via
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// "/proc/self/fd/" on Linux)
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if (fchmod(rw_fd, 0) != 0) {
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close(rw_fd);
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close(ro_fd);
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return false;
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}
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int ret;
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do {
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ret = ftruncate(rw_fd, size);
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} while (ret < 0 && errno == EINTR);
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if (ret < 0) {
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close(rw_fd);
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close(ro_fd);
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return false;
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}
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*rw_fd_ptr = rw_fd;
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*ro_fd_ptr = ro_fd;
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return true;
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}
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