git.oblomov.eu Git - linux-2.6/blob - arch/um/kernel/signal_kern.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/config.h"
   7 #include "linux/stddef.h"
   8 #include "linux/sys.h"
   9 #include "linux/sched.h"
  10 #include "linux/wait.h"
  11 #include "linux/kernel.h"
  12 #include "linux/smp_lock.h"
  13 #include "linux/module.h"
  14 #include "linux/slab.h"
  15 #include "linux/tty.h"
  16 #include "linux/binfmts.h"
  17 #include "linux/ptrace.h"
  18 #include "asm/signal.h"
  19 #include "asm/uaccess.h"
  20 #include "asm/unistd.h"
  21 #include "user_util.h"
  22 #include "asm/ucontext.h"
  23 #include "kern_util.h"
  24 #include "signal_kern.h"
  25 #include "kern.h"
  26 #include "frame_kern.h"
  27 #include "sigcontext.h"
  28 #include "mode.h"
  29
  30 EXPORT_SYMBOL(block_signals);
  31 EXPORT_SYMBOL(unblock_signals);
  32
  33 #define _S(nr) (1<<((nr)-1))
  34
  35 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
  36
  37 /*
  38  * OK, we're invoking a handler
  39  */
  40 static int handle_signal(struct pt_regs *regs, unsigned long signr,
  41                          struct k_sigaction *ka, siginfo_t *info,
  42                          sigset_t *oldset)
  43 {
  44         unsigned long sp;
  45         int err;
  46
  47         /* Always make any pending restarted system calls return -EINTR */
  48         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  49
  50         /* Did we come from a system call? */
  51         if(PT_REGS_SYSCALL_NR(regs) >= 0){
  52                 /* If so, check system call restarting.. */
  53                 switch(PT_REGS_SYSCALL_RET(regs)){
  54                 case -ERESTART_RESTARTBLOCK:
  55                 case -ERESTARTNOHAND:
  56                         PT_REGS_SYSCALL_RET(regs) = -EINTR;
  57                         break;
  58
  59                 case -ERESTARTSYS:
  60                         if (!(ka->sa.sa_flags & SA_RESTART)) {
  61                                 PT_REGS_SYSCALL_RET(regs) = -EINTR;
  62                                 break;
  63                         }
  64                 /* fallthrough */
  65                 case -ERESTARTNOINTR:
  66                         PT_REGS_RESTART_SYSCALL(regs);
  67                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
  68                         break;
  69                 }
  70         }
  71
  72         sp = PT_REGS_SP(regs);
  73         if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
  74                 sp = current->sas_ss_sp + current->sas_ss_size;
  75
  76 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
  77         if(!(ka->sa.sa_flags & SA_SIGINFO))
  78                 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
  79         else
  80 #endif
  81                 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
  82
  83         if(err){
  84                 spin_lock_irq(&current->sighand->siglock);
  85                 current->blocked = *oldset;
  86                 recalc_sigpending();
  87                 spin_unlock_irq(&current->sighand->siglock);
  88                 force_sigsegv(signr, current);
  89         } else {
  90                 spin_lock_irq(&current->sighand->siglock);
  91                 sigorsets(&current->blocked, &current->blocked,
  92                           &ka->sa.sa_mask);
  93                  if(!(ka->sa.sa_flags & SA_NODEFER))
  94                         sigaddset(&current->blocked, signr);
  95                 recalc_sigpending();
  96                 spin_unlock_irq(&current->sighand->siglock);
  97         }
  98
  99         return err;
 100 }
 101
 102 static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
 103 {
 104         struct k_sigaction ka_copy;
 105         siginfo_t info;
 106         int sig, handled_sig = 0;
 107
 108         while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
 109                 handled_sig = 1;
 110                 /* Whee!  Actually deliver the signal.  */
 111                 if(!handle_signal(regs, sig, &ka_copy, &info, oldset))
 112                         break;
 113         }
 114
 115         /* Did we come from a system call? */
 116         if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
 117                 /* Restart the system call - no handlers present */
 118                 if(PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOHAND ||
 119                    PT_REGS_SYSCALL_RET(regs) == -ERESTARTSYS ||
 120                    PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOINTR){
 121                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
 122                         PT_REGS_RESTART_SYSCALL(regs);
 123                 }
 124                 else if(PT_REGS_SYSCALL_RET(regs) == -ERESTART_RESTARTBLOCK){
 125                         PT_REGS_SYSCALL_RET(regs) = __NR_restart_syscall;
 126                         PT_REGS_RESTART_SYSCALL(regs);
 127                 }
 128         }
 129
 130         /* This closes a way to execute a system call on the host.  If
 131          * you set a breakpoint on a system call instruction and singlestep
 132          * from it, the tracing thread used to PTRACE_SINGLESTEP the process
 133          * rather than PTRACE_SYSCALL it, allowing the system call to execute
 134          * on the host.  The tracing thread will check this flag and
 135          * PTRACE_SYSCALL if necessary.
 136          */
 137         if(current->ptrace & PT_DTRACE)
 138                 current->thread.singlestep_syscall =
 139                         is_syscall(PT_REGS_IP(&current->thread.regs));
 140         return(handled_sig);
 141 }
 142
 143 int do_signal(void)
 144 {
 145         return(kern_do_signal(&current->thread.regs, &current->blocked));
 146 }
 147
 148 /*
 149  * Atomically swap in the new signal mask, and wait for a signal.
 150  */
 151 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 152 {
 153         sigset_t saveset;
 154
 155         mask &= _BLOCKABLE;
 156         spin_lock_irq(&current->sighand->siglock);
 157         saveset = current->blocked;
 158         siginitset(&current->blocked, mask);
 159         recalc_sigpending();
 160         spin_unlock_irq(&current->sighand->siglock);
 161
 162         PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
 163         while (1) {
 164                 current->state = TASK_INTERRUPTIBLE;
 165                 schedule();
 166                 if(kern_do_signal(&current->thread.regs, &saveset))
 167                         return(-EINTR);
 168         }
 169 }
 170
 171 long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
 172 {
 173         sigset_t saveset, newset;
 174
 175         /* XXX: Don't preclude handling different sized sigset_t's.  */
 176         if (sigsetsize != sizeof(sigset_t))
 177                 return -EINVAL;
 178
 179         if (copy_from_user(&newset, unewset, sizeof(newset)))
 180                 return -EFAULT;
 181         sigdelsetmask(&newset, ~_BLOCKABLE);
 182
 183         spin_lock_irq(&current->sighand->siglock);
 184         saveset = current->blocked;
 185         current->blocked = newset;
 186         recalc_sigpending();
 187         spin_unlock_irq(&current->sighand->siglock);
 188
 189         PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
 190         while (1) {
 191                 current->state = TASK_INTERRUPTIBLE;
 192                 schedule();
 193                 if (kern_do_signal(&current->thread.regs, &saveset))
 194                         return(-EINTR);
 195         }
 196 }
 197
 198 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 199 {
 200         return(do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs)));
 201 }
 202
 203 /*
 204  * Overrides for Emacs so that we follow Linus's tabbing style.
 205  * Emacs will notice this stuff at the end of the file and automatically
 206  * adjust the settings for this buffer only.  This must remain at the end
 207  * of the file.
 208  * ---------------------------------------------------------------------------
 209  * Local variables:
 210  * c-file-style: "linux"
 211  * End:
 212  */