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/ftrylockfile.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 src/stdio/ftrylockfile.c (limited to 'src/stdio/ftrylockfile.c') diff --git a/src/stdio/ftrylockfile.c b/src/stdio/ftrylockfile.c new file mode 100644 index 0000000..5065058 --- /dev/null +++ b/src/stdio/ftrylockfile.c @@ -0,0 +1,46 @@ +#include "stdio_impl.h" +#include "pthread_impl.h" +#include + +void __do_orphaned_stdio_locks() +{ + FILE *f; + for (f=__pthread_self()->stdio_locks; f; f=f->next_locked) + a_store(&f->lock, 0x40000000); +} + +void __unlist_locked_file(FILE *f) +{ + if (f->lockcount) { + if (f->next_locked) f->next_locked->prev_locked = f->prev_locked; + if (f->prev_locked) f->prev_locked->next_locked = f->next_locked; + else __pthread_self()->stdio_locks = f->next_locked; + } +} + +void __register_locked_file(FILE *f, pthread_t self) +{ + f->lockcount = 1; + f->prev_locked = 0; + f->next_locked = self->stdio_locks; + if (f->next_locked) f->next_locked->prev_locked = f; + self->stdio_locks = f; +} + +int ftrylockfile(FILE *f) +{ + pthread_t self = __pthread_self(); + int tid = self->tid; + int owner = f->lock; + if ((owner & ~MAYBE_WAITERS) == tid) { + if (f->lockcount == LONG_MAX) + return -1; + f->lockcount++; + return 0; + } + if (owner < 0) f->lock = owner = 0; + if (owner || a_cas(&f->lock, 0, tid)) + return -1; + __register_locked_file(f, self); + return 0; +} -- cgit v1.2.3