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musl/src/thread/__syscall_cp.c

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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"
use syscall_arg_t type for syscall prototypes in pthread code
2014-01-08 00:26:34 +01:00
#include "syscall.h"
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
mostly-cosmetic fixups to x32 port merge
2014-02-23 05:43:09 -05:00
static long sccp(syscall_arg_t nr,
syscall_arg_t u, syscall_arg_t v, syscall_arg_t w,
syscall_arg_t x, syscall_arg_t y, syscall_arg_t z)
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
{
return (__syscall)(nr, u, v, w, x, y, z);
}
rework cancellation weak alias logic not to depend on archive order if the order of object files in the static archive libc.a was not respected by the linker, the old logic could wrongly cause POSIX symbols outside of the ISO C namespace to be pulled into pure C programs. this should not happen with well-behaved linkers, but relying on the link order was a bad idea anyway. files are renamed to better reflect their contents now that they don't need names to control their order as members in the archive file.
2014-07-06 22:56:25 -04:00
weak_alias(sccp, __syscall_cp_c);
use weak aliases rather than function pointers to simplify some code
2011-08-06 20:09:51 -04:00
rework cancellation weak alias logic not to depend on archive order if the order of object files in the static archive libc.a was not respected by the linker, the old logic could wrongly cause POSIX symbols outside of the ISO C namespace to be pulled into pure C programs. this should not happen with well-behaved linkers, but relying on the link order was a bad idea anyway. files are renamed to better reflect their contents now that they don't need names to control their order as members in the archive file.
2014-07-06 22:56:25 -04:00
long (__syscall_cp)(syscall_arg_t nr,
syscall_arg_t u, syscall_arg_t v, syscall_arg_t w,
syscall_arg_t x, syscall_arg_t y, syscall_arg_t z)
use weak aliases rather than function pointers to simplify some code
2011-08-06 20:09:51 -04:00
{
rework cancellation weak alias logic not to depend on archive order if the order of object files in the static archive libc.a was not respected by the linker, the old logic could wrongly cause POSIX symbols outside of the ISO C namespace to be pulled into pure C programs. this should not happen with well-behaved linkers, but relying on the link order was a bad idea anyway. files are renamed to better reflect their contents now that they don't need names to control their order as members in the archive file.
2014-07-06 22:56:25 -04:00
return __syscall_cp_c(nr, u, v, w, x, y, z);
use weak aliases rather than function pointers to simplify some code
2011-08-06 20:09:51 -04:00
}
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