From eb2e298cdc814493a6ced8c05cf0d0f5cccc8b63 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sun, 28 Jul 2019 17:28:23 -0400 Subject: semtimedop: 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 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 is no change to the code after preprocessing. on current 32-bit archs, the time is passed via an intermediate copy to remove the assumption that time_t is a 32-bit type. to avoid duplicating SYS_ipc/SYS_semtimedop choice logic, the code for 32-bit archs "falls through" after updating the timeout argument ts to point to a [compound literal] array of longs. in preparation for "time64-only" 32-bit archs, an extra case is added for neither SYS_ipc nor the non-time64 SYS_semtimedop existing; the ENOSYS failure path here should never be reachable, and is added just in case a compiler can't see that it's not reachable, to avoid spurious static analysis complaints. --- src/ipc/semtimedop.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) (limited to 'src/ipc') diff --git a/src/ipc/semtimedop.c b/src/ipc/semtimedop.c index 51e70805..1632e7b0 100644 --- a/src/ipc/semtimedop.c +++ b/src/ipc/semtimedop.c @@ -1,13 +1,35 @@ #define _GNU_SOURCE #include +#include #include "syscall.h" #include "ipc.h" +#define IS32BIT(x) !((x)+0x80000000ULL>>32) +#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63)) + +#if !defined(SYS_semtimedop) && !defined(SYS_ipc) +#define NO_TIME32 1 +#else +#define NO_TIME32 0 +#endif + int semtimedop(int id, struct sembuf *buf, size_t n, const struct timespec *ts) { -#ifndef SYS_ipc +#ifdef SYS_semtimedop_time64 + time_t s = ts ? ts->tv_sec : 0; + long ns = ts ? ts->tv_nsec : 0; + int r = -ENOSYS; + if (NO_TIME32 || !IS32BIT(s)) + r = __syscall(SYS_semtimedop_time64, id, buf, n, + ts ? ((long long[]){s, ns}) : 0); + if (NO_TIME32 || r!=-ENOSYS) return __syscall_ret(r); + ts = ts ? (void *)(long[]){CLAMP(s), ns} : 0; +#endif +#if defined(SYS_ipc) + return syscall(SYS_ipc, IPCOP_semtimedop, id, n, 0, buf, ts); +#elif defined(SYS_semtimedop) return syscall(SYS_semtimedop, id, buf, n, ts); #else - return syscall(SYS_ipc, IPCOP_semtimedop, id, n, 0, buf, ts); + return __syscall_ret(-ENOSYS); #endif } -- cgit v1.2.1