int os_create_anonymous_file(std::size_t size)
{
static const char tmplate[] = "/wlc-shared-XXXXXX";
std::string path = getenv("XDG_RUNTIME_DIR");
if (path.empty())
return -1;
std::string name = path;
if(path.back() != '/') name.append("/");
name.append(tmplate);
int fd = create_tmpfile_cloexec(name.c_str());
if (fd < 0)
return -1;
int ret;
#if HAVE_POSIX_FALLOCATE
if ((ret = posix_fallocate(fd, 0, size)) != 0) {
close(fd);
errno = ret;
return -1;
}
#else
if ((ret = ftruncate(fd, size)) < 0) {
close(fd);
return -1;
}
#endif
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.
*/
int
os_create_anonymous_file(off_t size)
{
static const char file[] = "/weston-shared-XXXXXX";
const char *path;
char *name;
int fd;
path = getenv("XDG_RUNTIME_DIR");
if (!path) {
errno = ENOENT;
return -1;
}
name = (char*)malloc(strlen(path) + sizeof(file));
if (!name)
return -1;
strcpy(name, path);
strcat(name, file);
fd = create_tmpfile_cloexec(name);
free(name);
if (fd < 0)
return -1;
if (ftruncate(fd, size) < 0) {
close(fd);
return -1;
}
return fd;
}
