futex wait operations: add time64 syscall support, decouple 32-bit time_t

[musl] / src / thread / __timedwait.c

diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c
index 39eb996..666093b 100644 (file)
--- a/src/thread/__timedwait.c
+++ b/src/thread/__timedwait.c
@@ -3,19 +3,43 @@
 #include <errno.h>
 #include "futex.h"
 #include "syscall.h"
+#include "pthread_impl.h"
 
-int __timedwait(volatile int *addr, int val,
-       clockid_t clk, const struct timespec *at,
-       void (*cleanup)(void *), void *arg, int priv)
+#define IS32BIT(x) !((x)+0x80000000ULL>>32)
+#define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
+
+static int __futex4_cp(volatile void *addr, int op, int val, const struct timespec *to)
+{
+       int r;
+#ifdef SYS_futex_time64
+       time_t s = to ? to->tv_sec : 0;
+       long ns = to ? to->tv_nsec : 0;
+       r = -ENOSYS;
+       if (SYS_futex == SYS_futex_time64 || !IS32BIT(s))
+               r = __syscall_cp(SYS_futex_time64, addr, op, val,
+                       to ? ((long long[]){s, ns}) : 0);
+       if (SYS_futex == SYS_futex_time64 || r!=-ENOSYS) return r;
+       to = to ? (void *)(long[]){CLAMP(s), ns} : 0;
+#endif
+       r = __syscall_cp(SYS_futex, addr, op, val, to);
+       if (r != -ENOSYS) return r;
+       return __syscall_cp(SYS_futex, addr, op & ~FUTEX_PRIVATE, val, to);
+}
+
+static volatile int dummy = 0;
+weak_alias(dummy, __eintr_valid_flag);
+
+int __timedwait_cp(volatile int *addr, int val,
+       clockid_t clk, const struct timespec *at, int priv)
 {
-       int r, cs;
+       int r;
        struct timespec to, *top=0;
 
-       if (priv) priv = 128;
+       if (priv) priv = FUTEX_PRIVATE;
 
        if (at) {
                if (at->tv_nsec >= 1000000000UL) return EINVAL;
-               if (clock_gettime(clk, &to)) return EINVAL;
+               if (__clock_gettime(clk, &to)) return EINVAL;
                to.tv_sec = at->tv_sec - to.tv_sec;
                if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
                        to.tv_sec--;
@@ -25,15 +49,23 @@ int __timedwait(volatile int *addr, int val,
                top = &to;
        }
 
-       if (!cleanup) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
-       pthread_cleanup_push(cleanup, arg);
+       r = -__futex4_cp(addr, FUTEX_WAIT|priv, val, top);
+       if (r != EINTR && r != ETIMEDOUT && r != ECANCELED) r = 0;
+       /* Mitigate bug in old kernels wrongly reporting EINTR for non-
+        * interrupting (SA_RESTART) signal handlers. This is only practical
+        * when NO interrupting signal handlers have been installed, and
+        * works by sigaction tracking whether that's the case. */
+       if (r == EINTR && !__eintr_valid_flag) r = 0;
 
-       r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT|priv, val, top);
-       if (r == EINVAL) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
-       if (r != EINTR && r != ETIMEDOUT) r = 0;
-
-       pthread_cleanup_pop(0);
-       if (!cleanup) pthread_setcancelstate(cs, 0);
+       return r;
+}
 
+int __timedwait(volatile int *addr, int val,
+       clockid_t clk, const struct timespec *at, int priv)
+{
+       int cs, r;
+       __pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+       r = __timedwait_cp(addr, val, clk, at, priv);
+       __pthread_setcancelstate(cs, 0);
        return r;
 }