Hi, Thomas
On 2023-05-25 01:59:55+0800, Zhangjin Wu wrote:
rv32 uses the generic include/uapi/asm-generic/unistd.h and it has no __NR_pselect6 after kernel commit d4c08b9776b3 ("riscv: Use latest system call ABI"), use __NR_pselect6_time64 instead.
Signed-off-by: Zhangjin Wu falcon@tinylab.org
tools/include/nolibc/sys.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index c0335a84f880..00c7197dcd50 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -1041,8 +1041,13 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva struct timeval *t; } arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout }; return my_syscall1(__NR_select, &arg); -#elif defined(__ARCH_WANT_SYS_PSELECT6) && defined(__NR_pselect6) +#elif defined(__ARCH_WANT_SYS_PSELECT6) && (defined(__NR_pselect6) || defined(__NR_pselect6_time64)) +#ifdef __NR_pselect6 struct timespec t; +#else
- struct timespec64 t;
+#define __NR_pselect6 __NR_pselect6_time64
Wouldn't this #define leak to the users of nolibc and lead to calls to pselect6_time64 with the ABI of the __NR_pselect6 if userspace is doing its own raw syscalls?
Yeah, it would break the user-side raw __NR_pselect6 syscall for nolibc is a header-only libc, so, it is not safe to use such method like glibc.
Something like this will let the syscall call to pselect6_time64 instead of the user-required __NR_pselect6 and pass the wrong type of argument.
#include "nolibc.h" // If no __NR_pselect6 defined, __NR_pselect6 = __NR_pselect6_time64
#ifdef __NR_pselect6 struct timespec t; // come here for __NR_pselect6_time64, but t is not timespec64, broken syscall(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL); #else struct timespec64 t; syscall(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL); #endif
I have used something like __NR_pselect6_time3264 locally, before sending the patchset, I found a cleaner method already used in sys.h:
#ifndef __NR__newselect #define __NR__newselect __NR_select #endif
But I forgot the arguments mixing issue, __NR__newselect and __NR_select share the same type of arguments, but __NR_pselect6 and __NR_pselect6_time64 not, so, I will use back the old method but still need to find a better string, just like __NR__newselect, __NR__pselect6 may be used in kernel space in the future, and __NR_pselect6_time3264 is too long, what about this?
#ifdef __NR_pselect6 struct timespec t; #define __NR_pselect6__ __NR_pselect6 #else struct timespec64 t; #define __NR_pselect6__ __NR_pselect6_time64 #endif
Or even ___NR_pselect6?
The same issue is in this patch:
[PATCH 13/13] tools/nolibc: sys_gettimeofday: riscv: use __NR_clock_gettime64
will solve it with the same method.
Thanks, Zhangjin
+#endif if (timeout) { t.tv_sec = timeout->tv_sec; -- 2.25.1