diff options
Diffstat (limited to 'lib/xnanosleep.c')
| -rw-r--r-- | lib/xnanosleep.c | 47 |
1 files changed, 8 insertions, 39 deletions
diff --git a/lib/xnanosleep.c b/lib/xnanosleep.c index 8aa5e8a8de..fcfe3d551d 100644 --- a/lib/xnanosleep.c +++ b/lib/xnanosleep.c @@ -33,8 +33,6 @@ #include <time.h> #include "timespec.h" -#include "gethrxtime.h" -#include "xtime.h" /* The extra casts work around common compiler bugs. */ #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1)) @@ -48,19 +46,6 @@ # define TIME_T_MAX TYPE_MAXIMUM (time_t) #endif -/* POSIX.1-2001 requires that when a process is suspended, then - resumed, nanosleep (A, B) returns -1, sets errno to EINTR, and sets - *B to the time remaining at the point of resumption. However, some - versions of the Linux kernel incorrectly return the time remaining - at the point of suspension. Work around this bug on GNU/Linux - hosts by computing the remaining time here after nanosleep returns, - rather than by relying on nanosleep's computation. */ -#ifdef __linux__ -enum { NANOSLEEP_BUG_WORKAROUND = true }; -#else -enum { NANOSLEEP_BUG_WORKAROUND = false }; -#endif - /* Sleep until the time (call it WAKE_UP_TIME) specified as SECONDS seconds after the time this function is called. SECONDS must be non-negative. If SECONDS is so large that @@ -76,19 +61,9 @@ xnanosleep (double seconds) bool overflow = false; double ns; struct timespec ts_sleep; - xtime_t stop = 0; assert (0 <= seconds); - if (NANOSLEEP_BUG_WORKAROUND) - { - xtime_t now = gethrxtime (); - double increment = XTIME_PRECISION * seconds; - xtime_t incr = increment; - stop = now + incr + (incr < increment); - overflow = (stop < now); - } - /* Separate whole seconds from nanoseconds. Be careful to detect any overflow. */ ts_sleep.tv_sec = seconds; @@ -123,23 +98,17 @@ xnanosleep (double seconds) ts_sleep.tv_nsec = BILLION - 1; } + /* Linux-2.6.8.1's nanosleep returns -1, but doesn't set errno + when resumed after being suspended. Earlier versions would + set errno to EINTR. nanosleep from linux-2.6.10, as well as + implementations by (all?) other vendors, doesn't return -1 + in that case; either it continues sleeping (if time remains) + or it returns zero (if the wake-up time has passed). */ + errno = 0; if (nanosleep (&ts_sleep, NULL) == 0) break; - if (errno != EINTR) + if (errno != EINTR && errno != 0) return -1; - - if (NANOSLEEP_BUG_WORKAROUND) - { - xtime_t now = gethrxtime (); - if (stop <= now) - break; - else - { - xtime_t remaining = stop - now; - ts_sleep.tv_sec = xtime_nonnegative_sec (remaining); - ts_sleep.tv_nsec = xtime_nonnegative_nsec (remaining); - } - } } return 0; |