From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001 From: Vladimir Azarov Date: Tue, 1 Oct 2024 15:47:05 +0200 Subject: Initial version --- src/stdio/__lockfile.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 src/stdio/__lockfile.c (limited to 'src/stdio/__lockfile.c') diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c new file mode 100644 index 0000000..0f60a14 --- /dev/null +++ b/src/stdio/__lockfile.c @@ -0,0 +1,23 @@ +#include "stdio_impl.h" +#include "pthread_impl.h" + +int __lockfile(FILE *f) +{ + int owner = f->lock, tid = __pthread_self()->tid; + if ((owner & ~MAYBE_WAITERS) == tid) + return 0; + owner = a_cas(&f->lock, 0, tid); + if (!owner) return 1; + while ((owner = a_cas(&f->lock, 0, tid|MAYBE_WAITERS))) { + if ((owner & MAYBE_WAITERS) || + a_cas(&f->lock, owner, owner|MAYBE_WAITERS)==owner) + __futexwait(&f->lock, owner|MAYBE_WAITERS, 1); + } + return 1; +} + +void __unlockfile(FILE *f) +{ + if (a_swap(&f->lock, 0) & MAYBE_WAITERS) + __wake(&f->lock, 1, 1); +} -- cgit v1.2.3