use separate sigaction buffers for old and new data

in signal() it is needed since __sigaction uses restrict in parameters
and sharing the buffer is technically an aliasing error. do the same
for the syscall, as at least qemu-user does not handle it properly.

diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index 7a72a44..1f09bb9 100644 (file)
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -14,7 +14,7 @@ weak_alias(dummy, __pthread_self_def);
 
 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
 {
-       struct k_sigaction ksa;
+       struct k_sigaction ksa, ksa_old;
        if (sa) {
                if ((uintptr_t)sa->sa_handler > 1UL)
                        __pthread_self_def();
@@ -23,12 +23,12 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
                ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
                memcpy(&ksa.mask, &sa->sa_mask, sizeof ksa.mask);
        }
-       if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa:0, sizeof ksa.mask))
+       if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
                return -1;
        if (old) {
-               old->sa_handler = ksa.handler;
-               old->sa_flags = ksa.flags;
-               memcpy(&old->sa_mask, &ksa.mask, sizeof ksa.mask);
+               old->sa_handler = ksa_old.handler;
+               old->sa_flags = ksa_old.flags;
+               memcpy(&old->sa_mask, &ksa_old.mask, sizeof ksa_old.mask);
        }
        return 0;
 }

diff --git a/src/signal/signal.c b/src/signal/signal.c
index 07346a8..9d2f23a 100644 (file)
--- a/src/signal/signal.c
+++ b/src/signal/signal.c
@@ -7,10 +7,10 @@ int __sigaction(int, const struct sigaction *, struct sigaction *);
 
 void (*signal(int sig, void (*func)(int)))(int)
 {
-       struct sigaction sa = { .sa_handler = func, .sa_flags = SA_RESTART };
-       if (__sigaction(sig, &sa, &sa) < 0)
+       struct sigaction sa_old, sa = { .sa_handler = func, .sa_flags = SA_RESTART };
+       if (__sigaction(sig, &sa, &sa_old) < 0)
                return SIG_ERR;
-       return sa.sa_handler;
+       return sa_old.sa_handler;
 }
 
 weak_alias(signal, bsd_signal);