> I know that signal handlers can be recursive (tried it) so not going
>back through the kernel makes sense to me...
Here's some example code for this kind of thing. If you use it as it stands
you will only get one signal: since you aren't ever threading back out through
sys_rt_sigreturn the signal never gets unmasked. But if you are generating
signals internally in the kernel you can use force_sig to overcome that, and
you might then get the desired effect. I haven't tested it, of course.
This actually seems like quite a groovy idea; I might see if we can fix the
Arthur emulator to use the same trick.
p.
#include <signal.h>
#include <stdio.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
static void
my_handler(int sig, int _a2, int _a3, int _a4, struct siginfo *info,
struct ucontext *uc)
{
struct sigcontext *sc = &uc->uc_mcontext;
write(0, "B", 1); /* other stuff to taste */
my_longjmp(sc);
}
main()
{
struct sigaction sa, old;
sa.sa_handler = my_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_SIGINFO;
if (sigaction(SIGUSR1, &sa, &old))
{
perror("sigaction");
exit(1);
}
for (;;)
{
write(0, "A", 1);
raise(SIGUSR1);
}
}
--
.type my_longjmp, %function
.global my_longjmp
my_longjmp:
add r0, r0, #12
ldr r1, [r0, #16*4]
msr cpsr, r1
ldmia r0, {r0-pc}
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