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path: root/src/time/timer_settime.c
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2019-07-29timer_settime: add support for time64 syscall, decouple 32-bit time_tRich Felker1-0/+25
time64 syscall is used only if it's the only one defined for the arch, if either component of the itimerspec does not fit in 32 bits, or if time_t is 64-bit and the caller requested the old value, in which case there's a possibility that the old value might 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 moved through an intermediate copy to remove the assumption that time_t is a 32-bit type.
2014-01-06eliminate explicit (long) casts when making syscallsRich Felker1-1/+1
this practice came from very early, before internal/syscall.h defined macros that could accept pointer arguments directly and handle them correctly. aside from being ugly and unnecessary, it looks like it will be problematic when we add support for 32-bit ABIs on archs where registers (and syscall arguments) are 64-bit, e.g. x32 and mips n32.
2013-08-03fix multiple bugs in SIGEV_THREAD timersRich Felker1-1/+5
1. the thread result field was reused for storing a kernel timer id, but would be overwritten if the application code exited or cancelled the thread. 2. low pointer values were used as the indicator that the timer id is a kernel timer id rather than a thread id. this is not portable, as mmap may return low pointers on some conditions. instead, use the fact that pointers must be aligned and kernel timer ids must be non-negative to map pointers into the negative integer space. 3. signals were not blocked until after the timer thread started, so a race condition could allow a signal handler to run in the timer thread when it's not supposed to exist. this is mainly problematic if the calling thread was the only thread where the signal was unblocked and the signal handler assumes it runs in that thread.
2012-09-06use restrict everywhere it's required by c99 and/or posix 2008Rich Felker1-1/+1
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
2011-04-06fix signal-based timers with null sigevent argumentRich Felker1-2/+1
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.)
2011-03-30avoid all malloc/free in timer creation/destructionRich Felker1-1/+3
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.
2011-03-29implement POSIX timersRich Felker1-0/+7
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.