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.

diff --git a/src/thread/__syscall_cp.c b/src/thread/__syscall_cp.c
new file mode 100644 (file)
index 0000000..a48cee9
--- /dev/null
+++ b/src/thread/__syscall_cp.c
@@ -0,0 +1,18 @@
+#include "pthread_impl.h"
+#include "syscall.h"
+
+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)
+{
+       return (__syscall)(nr, u, v, w, x, y, z);
+}
+
+weak_alias(sccp, __syscall_cp_c);
+
+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)
+{
+       return __syscall_cp_c(nr, u, v, w, x, y, z);
+}

diff --git a/src/thread/cancel_dummy.c b/src/thread/cancel_dummy.c
deleted file mode 100644 (file)
index b630b02..0000000
--- a/src/thread/cancel_dummy.c
+++ /dev/null
@@ -1,17 +0,0 @@
-#include "pthread_impl.h"
-#include "syscall.h"
-
-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)
-{
-       return (__syscall)(nr, u, v, w, x, y, z);
-}
-
-weak_alias(sccp, __syscall_cp);
-
-static void dummy()
-{
-}
-
-weak_alias(dummy, __testcancel);

diff --git a/src/thread/cancel_impl.c b/src/thread/cancel_impl.c
deleted file mode 100644 (file)
index 069b279..0000000
--- a/src/thread/cancel_impl.c
+++ /dev/null
@@ -1,85 +0,0 @@
-#include "pthread_impl.h"
-#include "syscall.h"
-
-void __cancel()
-{
-       pthread_t self = __pthread_self();
-       self->canceldisable = 1;
-       self->cancelasync = 0;
-       pthread_exit(PTHREAD_CANCELED);
-}
-
-long __syscall_cp_asm(volatile void *, syscall_arg_t,
-                      syscall_arg_t, syscall_arg_t, syscall_arg_t,
-                      syscall_arg_t, syscall_arg_t, syscall_arg_t);
-
-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)
-{
-       pthread_t self;
-       long r;
-
-       if (!libc.has_thread_pointer || (self = __pthread_self())->canceldisable)
-               return __syscall(nr, u, v, w, x, y, z);
-
-       r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
-       if (r==-EINTR && nr!=SYS_close && self->cancel && !self->canceldisable)
-               __cancel();
-       return r;
-}
-
-static void _sigaddset(sigset_t *set, int sig)
-{
-       unsigned s = sig-1;
-       set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
-}
-
-static void cancel_handler(int sig, siginfo_t *si, void *ctx)
-{
-       pthread_t self = __pthread_self();
-       ucontext_t *uc = ctx;
-       const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP];
-       extern const char __cp_begin[1], __cp_end[1];
-
-       if (!self->cancel || self->canceldisable) return;
-
-       _sigaddset(&uc->uc_sigmask, SIGCANCEL);
-
-       if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) {
-               self->canceldisable = 1;
-               pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
-               __cancel();
-       }
-
-       __syscall(SYS_tkill, self->tid, SIGCANCEL);
-}
-
-void __testcancel()
-{
-       if (!libc.has_thread_pointer) return;
-       pthread_t self = __pthread_self();
-       if (self->cancel && !self->canceldisable)
-               __cancel();
-}
-
-static void init_cancellation()
-{
-       struct sigaction sa = {
-               .sa_flags = SA_SIGINFO | SA_RESTART,
-               .sa_sigaction = cancel_handler
-       };
-       sigfillset(&sa.sa_mask);
-       __libc_sigaction(SIGCANCEL, &sa, 0);
-}
-
-int pthread_cancel(pthread_t t)
-{
-       static int init;
-       if (!init) {
-               init_cancellation();
-               init = 1;
-       }
-       a_store(&t->cancel, 1);
-       return pthread_kill(t, SIGCANCEL);
-}

diff --git a/src/thread/pthread_cancel.c b/src/thread/pthread_cancel.c
new file mode 100644 (file)
index 0000000..e3d291e
--- /dev/null
+++ b/src/thread/pthread_cancel.c
@@ -0,0 +1,85 @@
+#include "pthread_impl.h"
+#include "syscall.h"
+
+void __cancel()
+{
+       pthread_t self = __pthread_self();
+       self->canceldisable = 1;
+       self->cancelasync = 0;
+       pthread_exit(PTHREAD_CANCELED);
+}
+
+long __syscall_cp_asm(volatile void *, syscall_arg_t,
+                      syscall_arg_t, syscall_arg_t, syscall_arg_t,
+                      syscall_arg_t, syscall_arg_t, syscall_arg_t);
+
+long __syscall_cp_c(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)
+{
+       pthread_t self;
+       long r;
+
+       if (!libc.has_thread_pointer || (self = __pthread_self())->canceldisable)
+               return __syscall(nr, u, v, w, x, y, z);
+
+       r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
+       if (r==-EINTR && nr!=SYS_close && self->cancel && !self->canceldisable)
+               __cancel();
+       return r;
+}
+
+static void _sigaddset(sigset_t *set, int sig)
+{
+       unsigned s = sig-1;
+       set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
+}
+
+static void cancel_handler(int sig, siginfo_t *si, void *ctx)
+{
+       pthread_t self = __pthread_self();
+       ucontext_t *uc = ctx;
+       const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP];
+       extern const char __cp_begin[1], __cp_end[1];
+
+       if (!self->cancel || self->canceldisable) return;
+
+       _sigaddset(&uc->uc_sigmask, SIGCANCEL);
+
+       if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) {
+               self->canceldisable = 1;
+               pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
+               __cancel();
+       }
+
+       __syscall(SYS_tkill, self->tid, SIGCANCEL);
+}
+
+void __testcancel()
+{
+       if (!libc.has_thread_pointer) return;
+       pthread_t self = __pthread_self();
+       if (self->cancel && !self->canceldisable)
+               __cancel();
+}
+
+static void init_cancellation()
+{
+       struct sigaction sa = {
+               .sa_flags = SA_SIGINFO | SA_RESTART,
+               .sa_sigaction = cancel_handler
+       };
+       sigfillset(&sa.sa_mask);
+       __libc_sigaction(SIGCANCEL, &sa, 0);
+}
+
+int pthread_cancel(pthread_t t)
+{
+       static int init;
+       if (!init) {
+               init_cancellation();
+               init = 1;
+       }
+       a_store(&t->cancel, 1);
+       return pthread_kill(t, SIGCANCEL);
+}

diff --git a/src/thread/pthread_testcancel.c b/src/thread/pthread_testcancel.c
index 33238c0..ba5f7c6 100644 (file)
--- a/src/thread/pthread_testcancel.c
+++ b/src/thread/pthread_testcancel.c
@@ -1,6 +1,11 @@
 #include "pthread_impl.h"
+#include "libc.h"
 
-void __testcancel(void);
+static void dummy()
+{
+}
+
+weak_alias(dummy, __testcancel);
 
 void pthread_testcancel()
 {