mirror of
https://gitlab.freedesktop.org/wlroots/wlroots.git
synced 2024-11-24 16:12:23 +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>
|
|
#include <fcntl.h>
|
|
#include <string.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/stat.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
#include <wlr/config.h>
|
|
#include "util/shm.h"
|
|
|
|
#define RANDNAME_PATTERN "/wlroots-XXXXXX"
|
|
|
|
static void randname(char *buf) {
|
|
struct timespec ts;
|
|
clock_gettime(CLOCK_REALTIME, &ts);
|
|
long r = ts.tv_nsec;
|
|
for (int i = 0; i < 6; ++i) {
|
|
buf[i] = 'A'+(r&15)+(r&16)*2;
|
|
r >>= 5;
|
|
}
|
|
}
|
|
|
|
static int excl_shm_open(char *name) {
|
|
int retries = 100;
|
|
do {
|
|
randname(name + strlen(RANDNAME_PATTERN) - 6);
|
|
|
|
--retries;
|
|
// CLOEXEC is guaranteed to be set by shm_open
|
|
int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
|
|
if (fd >= 0) {
|
|
return fd;
|
|
}
|
|
} while (retries > 0 && errno == EEXIST);
|
|
|
|
return -1;
|
|
}
|
|
|
|
int allocate_shm_file(size_t size) {
|
|
char name[] = RANDNAME_PATTERN;
|
|
int fd = excl_shm_open(name);
|
|
if (fd < 0) {
|
|
return -1;
|
|
}
|
|
shm_unlink(name);
|
|
|
|
int ret;
|
|
do {
|
|
ret = ftruncate(fd, size);
|
|
} while (ret < 0 && errno == EINTR);
|
|
if (ret < 0) {
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
|
|
return fd;
|
|
}
|
|
|
|
bool allocate_shm_file_pair(size_t size, int *rw_fd_ptr, int *ro_fd_ptr) {
|
|
char name[] = RANDNAME_PATTERN;
|
|
int rw_fd = excl_shm_open(name);
|
|
if (rw_fd < 0) {
|
|
return false;
|
|
}
|
|
|
|
// CLOEXEC is guaranteed to be set by shm_open
|
|
int ro_fd = shm_open(name, O_RDONLY, 0);
|
|
if (ro_fd < 0) {
|
|
shm_unlink(name);
|
|
close(rw_fd);
|
|
return false;
|
|
}
|
|
|
|
shm_unlink(name);
|
|
|
|
// Make sure the file cannot be re-opened in read-write mode (e.g. via
|
|
// "/proc/self/fd/" on Linux)
|
|
if (fchmod(rw_fd, 0) != 0) {
|
|
close(rw_fd);
|
|
close(ro_fd);
|
|
return false;
|
|
}
|
|
|
|
int ret;
|
|
do {
|
|
ret = ftruncate(rw_fd, size);
|
|
} while (ret < 0 && errno == EINTR);
|
|
if (ret < 0) {
|
|
close(rw_fd);
|
|
close(ro_fd);
|
|
return false;
|
|
}
|
|
|
|
*rw_fd_ptr = rw_fd;
|
|
*ro_fd_ptr = ro_fd;
|
|
return true;
|
|
}
|