Pileus Git - ~andy/linux/blob - arch/um/kernel/signal.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/stddef.h"
   7 #include "linux/sys.h"
   8 #include "linux/sched.h"
   9 #include "linux/wait.h"
  10 #include "linux/kernel.h"
  11 #include "linux/smp_lock.h"
  12 #include "linux/module.h"
  13 #include "linux/slab.h"
  14 #include "linux/tty.h"
  15 #include "linux/binfmts.h"
  16 #include "linux/ptrace.h"
  17 #include "asm/signal.h"
  18 #include "asm/uaccess.h"
  19 #include "asm/unistd.h"
  20 #include "asm/ucontext.h"
  21 #include "kern_util.h"
  22 #include "signal_kern.h"
  23 #include "kern.h"
  24 #include "frame_kern.h"
  25 #include "sigcontext.h"
  26
  27 EXPORT_SYMBOL(block_signals);
  28 EXPORT_SYMBOL(unblock_signals);
  29
  30 #define _S(nr) (1<<((nr)-1))
  31
  32 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
  33
  34 /*
  35  * OK, we're invoking a handler
  36  */
  37 static int handle_signal(struct pt_regs *regs, unsigned long signr,
  38                          struct k_sigaction *ka, siginfo_t *info,
  39                          sigset_t *oldset)
  40 {
  41         unsigned long sp;
  42         int err;
  43
  44         /* Always make any pending restarted system calls return -EINTR */
  45         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  46
  47         /* Did we come from a system call? */
  48         if(PT_REGS_SYSCALL_NR(regs) >= 0){
  49                 /* If so, check system call restarting.. */
  50                 switch(PT_REGS_SYSCALL_RET(regs)){
  51                 case -ERESTART_RESTARTBLOCK:
  52                 case -ERESTARTNOHAND:
  53                         PT_REGS_SYSCALL_RET(regs) = -EINTR;
  54                         break;
  55
  56                 case -ERESTARTSYS:
  57                         if (!(ka->sa.sa_flags & SA_RESTART)) {
  58                                 PT_REGS_SYSCALL_RET(regs) = -EINTR;
  59                                 break;
  60                         }
  61                 /* fallthrough */
  62                 case -ERESTARTNOINTR:
  63                         PT_REGS_RESTART_SYSCALL(regs);
  64                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
  65                         break;
  66                 }
  67         }
  68
  69         sp = PT_REGS_SP(regs);
  70         if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
  71                 sp = current->sas_ss_sp + current->sas_ss_size;
  72
  73 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
  74         if(!(ka->sa.sa_flags & SA_SIGINFO))
  75                 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
  76         else
  77 #endif
  78                 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
  79
  80         if(err){
  81                 spin_lock_irq(&current->sighand->siglock);
  82                 current->blocked = *oldset;
  83                 recalc_sigpending();
  84                 spin_unlock_irq(&current->sighand->siglock);
  85                 force_sigsegv(signr, current);
  86         } else {
  87                 spin_lock_irq(&current->sighand->siglock);
  88                 sigorsets(&current->blocked, &current->blocked,
  89                           &ka->sa.sa_mask);
  90                  if(!(ka->sa.sa_flags & SA_NODEFER))
  91                         sigaddset(&current->blocked, signr);
  92                 recalc_sigpending();
  93                 spin_unlock_irq(&current->sighand->siglock);
  94         }
  95
  96         return err;
  97 }
  98
  99 static int kern_do_signal(struct pt_regs *regs)
 100 {
 101         struct k_sigaction ka_copy;
 102         siginfo_t info;
 103         sigset_t *oldset;
 104         int sig, handled_sig = 0;
 105
 106         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 107                 oldset = &current->saved_sigmask;
 108         else
 109                 oldset = &current->blocked;
 110
 111         while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
 112                 handled_sig = 1;
 113                 /* Whee!  Actually deliver the signal.  */
 114                 if(!handle_signal(regs, sig, &ka_copy, &info, oldset)){
 115                         /* a signal was successfully delivered; the saved
 116                          * sigmask will have been stored in the signal frame,
 117                          * and will be restored by sigreturn, so we can simply
 118                          * clear the TIF_RESTORE_SIGMASK flag */
 119                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 120                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 121                         break;
 122                 }
 123         }
 124
 125         /* Did we come from a system call? */
 126         if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
 127                 /* Restart the system call - no handlers present */
 128                 switch(PT_REGS_SYSCALL_RET(regs)){
 129                 case -ERESTARTNOHAND:
 130                 case -ERESTARTSYS:
 131                 case -ERESTARTNOINTR:
 132                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
 133                         PT_REGS_RESTART_SYSCALL(regs);
 134                         break;
 135                 case -ERESTART_RESTARTBLOCK:
 136                         PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
 137                         PT_REGS_RESTART_SYSCALL(regs);
 138                         break;
 139                 }
 140         }
 141
 142         /* This closes a way to execute a system call on the host.  If
 143          * you set a breakpoint on a system call instruction and singlestep
 144          * from it, the tracing thread used to PTRACE_SINGLESTEP the process
 145          * rather than PTRACE_SYSCALL it, allowing the system call to execute
 146          * on the host.  The tracing thread will check this flag and
 147          * PTRACE_SYSCALL if necessary.
 148          */
 149         if(current->ptrace & PT_DTRACE)
 150                 current->thread.singlestep_syscall =
 151                         is_syscall(PT_REGS_IP(&current->thread.regs));
 152
 153         /* if there's no signal to deliver, we just put the saved sigmask
 154          * back */
 155         if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
 156                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 157                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 158         }
 159         return handled_sig;
 160 }
 161
 162 int do_signal(void)
 163 {
 164         return kern_do_signal(&current->thread.regs);
 165 }
 166
 167 /*
 168  * Atomically swap in the new signal mask, and wait for a signal.
 169  */
 170 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 171 {
 172         mask &= _BLOCKABLE;
 173         spin_lock_irq(&current->sighand->siglock);
 174         current->saved_sigmask = current->blocked;
 175         siginitset(&current->blocked, mask);
 176         recalc_sigpending();
 177         spin_unlock_irq(&current->sighand->siglock);
 178
 179         current->state = TASK_INTERRUPTIBLE;
 180         schedule();
 181         set_thread_flag(TIF_RESTORE_SIGMASK);
 182         return -ERESTARTNOHAND;
 183 }
 184
 185 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 186 {
 187         return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
 188 }