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path: root/src/time
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2011-04-06fix signal-based timers with null sigevent argumentRich Felker-28/+19
since timer_create is no longer allocating a structure for the timer_t and simply using the kernel timer id, it was impossible to specify the timer_t as the argument to the signal handler. the solution is to pass the null sigevent pointer on to the kernel, rather than filling it in userspace, so that the kernel does the right thing. however, that precludes the clever timerid-versus-threadid encoding we were doing. instead, just assume timerids are below 1M and thread pointers are above 1M. (in perspective: timerids are sequentially allocated and seem limited to 32k, and thread pointers are at roughly 3G.)
2011-04-03timer threads should sleep and stay asleep... a long timeRich Felker-1/+1
2011-04-03revert to deleting kernel-level timer from cancellation handlerRich Felker-7/+11
this is necessary in order to avoid breaking timer_getoverrun in the last run of the timer event handler, if it has not yet finished.
2011-04-03simplify calling of timer signal handlerRich Felker-3/+1
2011-03-30avoid all malloc/free in timer creation/destructionRich Felker-29/+20
instead of allocating a userspace structure for signal-based timers, simply use the kernel timer id. we use the fact that thread pointers will always be zero in the low bit (actually more) to encode integer timerid values as pointers. also, this change ensures that the timer_destroy syscall has completed before the library timer_destroy function returns, in case it matters.
2011-03-30optimize timer creation and possibly protect against some minor racesRich Felker-14/+19
the major idea of this patch is not to depend on having the timer pointer delivered to the signal handler, and instead use the thread pointer to get the callback function address and argument. this way, the parent thread can make the timer_create syscall while the child thread is starting, and it should never have to block waiting for the barrier.
2011-03-29reorder timer initialization so that timer_create does not depend on freeRich Felker-9/+17
this allows small programs which only create times, but never delete them, to use simple_malloc instead of the full malloc.
2011-03-29implement POSIX timersRich Felker-0/+143
this implementation is superior to the glibc/nptl implementation, in that it gives true realtime behavior. there is no risk of timer expiration events being lost due to failed thread creation or failed malloc, because the thread is created as time creation time, and reused until the timer is deleted.
2011-03-24overhaul cancellation to fix resource leaks and dangerous behavior with signalsRich Felker-0/+1
this commit addresses two issues: 1. a race condition, whereby a cancellation request occurring after a syscall returned from kernelspace but before the subsequent CANCELPT_END would cause cancellable resource-allocating syscalls (like open) to leak resources. 2. signal handlers invoked while the thread was blocked at a cancellation point behaved as if asynchronous cancellation mode wer in effect, resulting in potentially dangerous state corruption if a cancellation request occurs. the glibc/nptl implementation of threads shares both of these issues. with this commit, both are fixed. however, cancellation points encountered in a signal handler will not be acted upon if the signal was received while the thread was already at a cancellation point. they will of course be acted upon after the signal handler returns, so in real-world usage where signal handlers quickly return, it should not be a problem. it's possible to solve this problem too by having sigaction() wrap all signal handlers with a function that uses a pthread_cleanup handler to catch cancellation, patch up the saved context, and return into the cancellable function that will catch and act upon the cancellation. however that would be a lot of complexity for minimal if any benefit...
2011-03-20global cleanup to use the new syscall interfaceRich Felker-11/+6
2011-03-19if returning errno value directly from a syscall, we need to negate it.Rich Felker-1/+1
2011-03-19syscall overhaul part two - unify public and internal syscall interfaceRich Felker-6/+3
with this patch, the syscallN() functions are no longer needed; a variadic syscall() macro allows syscalls with anywhere from 0 to 6 arguments to be made with a single macro name. also, manually casting each non-integer argument with (long) is no longer necessary; the casts are hidden in the macros. some source files which depended on being able to define the old macro SYSCALL_RETURNS_ERRNO have been modified to directly use __syscall() instead of syscall(). references to SYSCALL_SIGSET_SIZE and SYSCALL_LL have also been changed. x86_64 has not been tested, and may need a follow-up commit to fix any minor bugs/oversights.
2011-03-12misplaced & in times() made it fail to work, and clobber the stackRich Felker-1/+1
2011-03-10more cancellation points: tcdrain, clock_nanosleepRich Felker-1/+6
2011-03-10fix errno behavior in clock_* functionsRich Felker-3/+0
these functions are specified inconsistent in whether they're specified to return an error value, or return -1 and set errno. hopefully now they all match what POSIX requires.
2011-02-19implement the remaining clock_* interfacesRich Felker-0/+36
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker-0/+874