Commit 45d62326 authored by Brad King's avatar Brad King
Browse files

BUG: Mask signals during SystemTools::Delay to avoid interrupted sleep.

parent 2f278ce4
......@@ -56,6 +56,7 @@
#include <sys/ioctl.h>
#include <unistd.h>
#include <termios.h>
#include <signal.h> /* sigprocmask */
// Windows API. Some parts used even on cygwin.
......@@ -3546,7 +3547,34 @@ void SystemTools::Delay(unsigned int msec)
#ifdef _WIN32
usleep(msec * 1000);
// Block signals to make sure the entire sleep duration occurs. If
// a signal were to arrive the sleep or usleep might return early
// and there is no way to accurately know how much time was really
// slept without setting up timers.
sigset_t newset;
sigset_t oldset;
sigprocmask(SIG_BLOCK, &newset, &oldset);
// The sleep function gives 1 second resolution and the usleep
// function gives 1e-6 second resolution but on some platforms has a
// maximum sleep time of 1 second. This could be re-implemented to
// use select with masked signals or pselect to mask signals
// atomically. If select is given empty sets and zero as the max
// file descriptor but a non-zero timeout it can be used to block
// for a precise amount of time.
if(msec >= 1000)
sleep(msec / 1000);
usleep((msec % 1000) * 1000);
usleep(msec * 1000);
// Restore the signal mask to the previous setting.
sigprocmask(SIG_SETMASK, &oldset, 0);
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