From 22276671d031639f1bd55d7dbf817290c321c7bf Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sun, 28 Jul 2019 18:15:22 -0400 Subject: [PATCH] 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 +++++++++++++++++- src/select/pselect.c | 20 +++++++++++++++++--- 2 files changed, 34 insertions(+), 4 deletions(-) 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); } diff --git a/src/select/pselect.c b/src/select/pselect.c index 762af37f..54cfb291 100644 --- a/src/select/pselect.c +++ b/src/select/pselect.c @@ -1,12 +1,26 @@ #include #include #include +#include #include "syscall.h" +#define IS32BIT(x) !((x)+0x80000000ULL>>32) +#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63)) + int pselect(int n, fd_set *restrict rfds, fd_set *restrict wfds, fd_set *restrict efds, const struct timespec *restrict ts, const sigset_t *restrict mask) { syscall_arg_t data[2] = { (uintptr_t)mask, _NSIG/8 }; - struct timespec ts_tmp; - if (ts) ts_tmp = *ts; - return syscall_cp(SYS_pselect6, n, rfds, wfds, efds, ts ? &ts_tmp : 0, data); + time_t s = ts ? ts->tv_sec : 0; + long ns = ts ? ts->tv_nsec : 0; +#ifdef SYS_pselect6_time64 + int r = -ENOSYS; + if (SYS_pselect6 == SYS_pselect6_time64 || !IS32BIT(s)) + r = __syscall_cp(SYS_pselect6_time64, n, rfds, wfds, efds, + ts ? ((long long[]){s, ns}) : 0, data); + if (SYS_pselect6 == SYS_pselect6_time64 || r!=-ENOSYS) + return __syscall_ret(r); + s = CLAMP(s); +#endif + return syscall_cp(SYS_pselect6, n, rfds, wfds, efds, + ts ? ((long[]){s, ns}) : 0, data); } -- GitLab