glibc/include/sys/select.h
Adhemerval Zanella 4c3df0eba5 linux: Only use 64-bit syscall if required for select
For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.  This also avoids the need
to use supports_time64() (which breaks the usage case of live migration
like CRIU or similar).

It also fixes an issue on 32-bit select call for !__ASSUME_PSELECT
(microblase with older kernels only) where the expected timeout
is a 'struct timeval' instead of 'struct timespec'.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
2021-06-22 12:09:52 -03:00

48 lines
1.4 KiB
C

#ifndef _SYS_SELECT_H
#include <misc/sys/select.h>
#ifndef _ISOMAC
/* Now define the internal interfaces. */
# if __TIMESIZE == 64
# define __pselect64 __pselect
# define __select64 __select
#else
# include <struct___timespec64.h>
# include <struct___timeval64.h>
extern int __pselect64 (int __nfds, fd_set *__readfds,
fd_set *__writefds, fd_set *__exceptfds,
const struct __timespec64 *__timeout,
const __sigset_t *__sigmask);
libc_hidden_proto (__pselect64)
extern int __pselect32 (int __nfds, fd_set *__readfds,
fd_set *__writefds, fd_set *__exceptfds,
const struct __timespec64 *__timeout,
const __sigset_t *__sigmask)
attribute_hidden;
extern int __select32 (int __nfds, fd_set *__readfds,
fd_set *__writefds, fd_set *__exceptfds,
const struct __timespec64 *ts64,
struct __timeval64 *timeout)
attribute_hidden;
extern int __select64 (int __nfds, fd_set *__readfds,
fd_set *__writefds, fd_set *__exceptfds,
struct __timeval64 *__timeout);
libc_hidden_proto (__select64)
#endif
extern int __pselect (int __nfds, fd_set *__readfds,
fd_set *__writefds, fd_set *__exceptfds,
const struct timespec *__timeout,
const __sigset_t *__sigmask);
extern int __select (int __nfds, fd_set *__restrict __readfds,
fd_set *__restrict __writefds,
fd_set *__restrict __exceptfds,
struct timeval *__restrict __timeout);
libc_hidden_proto (__select)
#endif
#endif