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/*
* Copyright (C) 2004 PathScale, Inc
* Licensed under the GPL
*/
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#include <sys/mman.h>
#include "user_util.h"
#include "user.h"
#include "signal_kern.h"
#include "sysdep/sigcontext.h"
#include "sigcontext.h"
#include "mode.h"
#include "os.h"
/* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled
* together under SIGVTALRM_BIT. SIGPROF is excluded because we want to
* be able to profile all of UML, not just the non-critical sections. If
* profiling is not thread-safe, then that is not my problem. We can disable
* profiling when SMP is enabled in that case.
*/
#define SIGIO_BIT 0
#define SIGIO_MASK (1 << SIGIO_BIT)
#define SIGVTALRM_BIT 1
#define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
#define SIGALRM_BIT 2
#define SIGALRM_MASK (1 << SIGALRM_BIT)
static int signals_enabled = 1;
static int pending = 0;
void sig_handler(int sig, struct sigcontext *sc)
{
int enabled;
enabled = signals_enabled;
if(!enabled && (sig == SIGIO)){
pending |= SIGIO_MASK;
return;
}
block_signals();
CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
sig, sc);
set_signals(enabled);
}
static void real_alarm_handler(int sig, struct sigcontext *sc)
{
if(sig == SIGALRM)
switch_timers(0);
CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
sig, sc);
if(sig == SIGALRM)
switch_timers(1);
}
void alarm_handler(int sig, struct sigcontext *sc)
{
int enabled;
enabled = signals_enabled;
if(!signals_enabled){
if(sig == SIGVTALRM)
pending |= SIGVTALRM_MASK;
else pending |= SIGALRM_MASK;
return;
}
block_signals();
real_alarm_handler(sig, sc);
set_signals(enabled);
}
void set_sigstack(void *sig_stack, int size)
{
stack_t stack = ((stack_t) { .ss_flags = 0,
.ss_sp = (__ptr_t) sig_stack,
.ss_size = size - sizeof(void *) });
if(sigaltstack(&stack, NULL) != 0)
panic("enabling signal stack failed, errno = %d\n", errno);
}
void remove_sigstack(void)
{
stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE,
.ss_sp = NULL,
.ss_size = 0 });
if(sigaltstack(&stack, NULL) != 0)
panic("disabling signal stack failed, errno = %d\n", errno);
}
void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
extern void hard_handler(int sig);
void set_handler(int sig, void (*handler)(int), int flags, ...)
{
struct sigaction action;
va_list ap;
sigset_t sig_mask;
int mask;
handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
action.sa_handler = hard_handler;
sigemptyset(&action.sa_mask);
va_start(ap, flags);
while((mask = va_arg(ap, int)) != -1)
sigaddset(&action.sa_mask, mask);
va_end(ap);
action.sa_flags = flags;
action.sa_restorer = NULL;
if(sigaction(sig, &action, NULL) < 0)
panic("sigaction failed - errno = %d\n", errno);
sigemptyset(&sig_mask);
sigaddset(&sig_mask, sig);
if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
panic("sigprocmask failed - errno = %d\n", errno);
}
int change_sig(int signal, int on)
{
sigset_t sigset, old;
sigemptyset(&sigset);
sigaddset(&sigset, signal);
sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
return(!sigismember(&old, signal));
}
void block_signals(void)
{
signals_enabled = 0;
}
void unblock_signals(void)
{
int save_pending;
if(signals_enabled == 1)
return;
/* We loop because the IRQ handler returns with interrupts off. So,
* interrupts may have arrived and we need to re-enable them and
* recheck pending.
*/
while(1){
/* Save and reset save_pending after enabling signals. This
* way, pending won't be changed while we're reading it.
*/
signals_enabled = 1;
save_pending = pending;
if(save_pending == 0)
return;
pending = 0;
/* We have pending interrupts, so disable signals, as the
* handlers expect them off when they are called. They will
* be enabled again above.
*/
signals_enabled = 0;
/* Deal with SIGIO first because the alarm handler might
* schedule, leaving the pending SIGIO stranded until we come
* back here.
*/
if(save_pending & SIGIO_MASK)
CHOOSE_MODE_PROC(sig_handler_common_tt,
sig_handler_common_skas, SIGIO, NULL);
if(save_pending & SIGALRM_MASK)
real_alarm_handler(SIGALRM, NULL);
if(save_pending & SIGVTALRM_MASK)
real_alarm_handler(SIGVTALRM, NULL);
}
}
int get_signals(void)
{
return signals_enabled;
}
int set_signals(int enable)
{
int ret;
if(signals_enabled == enable)
return enable;
ret = signals_enabled;
if(enable)
unblock_signals();
else block_signals();
return ret;
}
void os_usr1_signal(int on)
{
change_sig(SIGUSR1, on);
}
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