path: root/src/ipc
diff options
authorRich Felker <>2019-07-28 17:28:23 -0400
committerRich Felker <>2019-07-28 17:28:23 -0400
commiteb2e298cdc814493a6ced8c05cf0d0f5cccc8b63 (patch)
treeacc547c8a83dc254df143142ccd2048c2ea50355 /src/ipc
parent68c983919ecfa75a8216d93b85baaefcb7b6e51c (diff)
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.
Diffstat (limited to 'src/ipc')
1 files changed, 24 insertions, 2 deletions
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 <sys/sem.h>
+#include <errno.h>
#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
+#define NO_TIME32 0
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;
+#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);
- return syscall(SYS_ipc, IPCOP_semtimedop, id, n, 0, buf, ts);
+ return __syscall_ret(-ENOSYS);