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bees/lib/openat2.cc
Zygo Blaxell ad11db2ee1 openat2: supply the missing definitions for building with old headers and new kernel
Apparently Ubuntu 20 has upgraded to kernel 5.15, but still builds things
with 5.4 headers.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2025-01-19 22:20:06 -05:00

41 lines
707 B
C++

#include "crucible/openat2.h"
#include <sys/syscall.h>
// Compatibility for building on old libc for new kernel
#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 6, 0)
// Every arch that defines this uses 437, except Alpha, where 437 is
// mq_getsetattr.
#ifndef SYS_openat2
#ifdef __alpha__
#define SYS_openat2 547
#else
#define SYS_openat2 437
#endif
#endif
#endif // Linux version >= v5.6
#include <fcntl.h>
#include <unistd.h>
extern "C" {
int
__attribute__((weak))
openat2(int const dirfd, const char *const pathname, struct open_how *const how, size_t const size)
throw()
{
#ifdef SYS_openat2
return syscall(SYS_openat2, dirfd, pathname, how, size);
#else
errno = ENOSYS;
return -1;
#endif
}
};