musl/src/thread/cancel_dummy.c

#include "pthread_impl.h"

static long sccp(long nr, long u, long v, long w, long x, long y, long z)
{
	return (__syscall)(nr, u, v, w, x, y, z);
}

weak_alias(sccp, __syscall_cp);

static void dummy()
{
}

weak_alias(dummy, __testcancel);
overhaul pthread cancellation this patch improves the correctness, simplicity, and size of cancellation-related code. modulo any small errors, it should now be completely conformant, safe, and resource-leak free. the notion of entering and exiting cancellation-point context has been completely eliminated and replaced with alternative syscall assembly code for cancellable syscalls. the assembly is responsible for setting up execution context information (stack pointer and address of the syscall instruction) which the cancellation signal handler can use to determine whether the interrupted code was in a cancellable state. these changes eliminate race conditions in the previous generation of cancellation handling code (whereby a cancellation request received just prior to the syscall would not be processed, leaving the syscall to block, potentially indefinitely), and remedy an issue where non-cancellable syscalls made from signal handlers became cancellable if the signal handler interrupted a cancellation point. x86_64 asm is untested and may need a second try to get it right. 2011-04-17 11:43:03 -04:00			`#include "pthread_impl.h"`

			`static long sccp(long nr, long u, long v, long w, long x, long y, long z)`
			`{`
			`return (__syscall)(nr, u, v, w, x, y, z);`
			`}`

			`weak_alias(sccp, __syscall_cp);`
use weak aliases rather than function pointers to simplify some code 2011-08-06 20:09:51 -04:00
			`static void dummy()`
			`{`
			`}`

			`weak_alias(dummy, __testcancel);`