From 22276671d031639f1bd55d7dbf817290c321c7bf Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sun, 28 Jul 2019 18:15:22 -0400 Subject: pselect, ppoll: add time64 syscall support, decouple 32-bit time_t time64 syscall is used only if it's the only one defined for the arch, or if the requested timeout length does not fit in 32 bits. on current 32-bit archs where time_t is a 32-bit type, this makes it statically unreachable. on 64-bit archs, there are only superficial changes to the code after preprocessing. both before and after these changes, these functions copied their timeout arguments to avoid letting the kernel clobber the caller's copies. now, the copying also serves to change the type from userspace timespec to a pair of longs, which makes a difference only in the 32-bit fallback case, not on 64-bit. --- src/linux/ppoll.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'src/linux') diff --git a/src/linux/ppoll.c b/src/linux/ppoll.c index 9e262477..e614600a 100644 --- a/src/linux/ppoll.c +++ b/src/linux/ppoll.c @@ -1,10 +1,26 @@ #define _GNU_SOURCE #include #include +#include #include "syscall.h" +#define IS32BIT(x) !((x)+0x80000000ULL>>32) +#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63)) + int ppoll(struct pollfd *fds, nfds_t n, const struct timespec *to, const sigset_t *mask) { + time_t s = to ? to->tv_sec : 0; + long ns = to ? to->tv_nsec : 0; +#ifdef SYS_ppoll_time64 + int r = -ENOSYS; + if (SYS_ppoll == SYS_ppoll_time64 || !IS32BIT(s)) + r = __syscall_cp(SYS_ppoll_time64, fds, n, + to ? ((long long[]){s, ns}) : 0, + mask, _NSIG/8); + if (SYS_ppoll == SYS_ppoll_time64 || r != -ENOSYS) + return __syscall_ret(r); + s = CLAMP(s); +#endif return syscall_cp(SYS_ppoll, fds, n, - to ? (struct timespec []){*to} : 0, mask, _NSIG/8); + to ? ((long[]){s, ns}) : 0, mask, _NSIG/8); } -- cgit v1.2.1