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 "signal_user.h"
  26 #include "kern.h"
  27 #include "frame_kern.h"
  28 #include "sigcontext.h"
  29 #include "mode.h"
  30
  31 EXPORT_SYMBOL(block_signals);
  32 EXPORT_SYMBOL(unblock_signals);
  33
  34 #define _S(nr) (1<<((nr)-1))
  35
  36 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
  37
  38 /*
  39  * OK, we're invoking a handler
  40  */
  41 static int handle_signal(struct pt_regs *regs, unsigned long signr,
  42                          struct k_sigaction *ka, siginfo_t *info,
  43                          sigset_t *oldset)
  44 {
  45         unsigned long sp;
  46         int err;
  47
  48         /* Always make any pending restarted system calls return -EINTR */
  49         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  50
  51         /* Did we come from a system call? */
  52         if(PT_REGS_SYSCALL_NR(regs) >= 0){
  53                 /* If so, check system call restarting.. */
  54                 switch(PT_REGS_SYSCALL_RET(regs)){
  55                 case -ERESTART_RESTARTBLOCK:
  56                 case -ERESTARTNOHAND:
  57                         PT_REGS_SYSCALL_RET(regs) = -EINTR;
  58                         break;
  59
  60                 case -ERESTARTSYS:
  61                         if (!(ka->sa.sa_flags & SA_RESTART)) {
  62                                 PT_REGS_SYSCALL_RET(regs) = -EINTR;
  63                                 break;
  64                         }
  65                 /* fallthrough */
  66                 case -ERESTARTNOINTR:
  67                         PT_REGS_RESTART_SYSCALL(regs);
  68                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
  69                         break;
  70                 }
  71         }
  72
  73         sp = PT_REGS_SP(regs);
  74         if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
  75                 sp = current->sas_ss_sp + current->sas_ss_size;
  76
  77 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
  78         if(!(ka->sa.sa_flags & SA_SIGINFO))
  79                 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
  80         else
  81 #endif
  82                 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
  83
  84         if(err){
  85                 spin_lock_irq(&current->sighand->siglock);
  86                 current->blocked = *oldset;
  87                 recalc_sigpending();
  88                 spin_unlock_irq(&current->sighand->siglock);
  89                 force_sigsegv(signr, current);
  90         } else {
  91                 spin_lock_irq(&current->sighand->siglock);
  92                 sigorsets(&current->blocked, &current->blocked,
  93                           &ka->sa.sa_mask);
  94                  if(!(ka->sa.sa_flags & SA_NODEFER))
  95                         sigaddset(&current->blocked, signr);
  96                 recalc_sigpending();
  97                 spin_unlock_irq(&current->sighand->siglock);
  98         }
  99
 100         return err;
 101 }
 102
 103 static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
 104 {
 105         struct k_sigaction ka_copy;
 106         siginfo_t info;
 107         int sig, handled_sig = 0;
 108
 109         while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
 110                 handled_sig = 1;
 111                 /* Whee!  Actually deliver the signal.  */
 112                 if(!handle_signal(regs, sig, &ka_copy, &info, oldset))
 113                         break;
 114         }
 115
 116         /* Did we come from a system call? */
 117         if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
 118                 /* Restart the system call - no handlers present */
 119                 if(PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOHAND ||
 120                    PT_REGS_SYSCALL_RET(regs) == -ERESTARTSYS ||
 121                    PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOINTR){
 122                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
 123                         PT_REGS_RESTART_SYSCALL(regs);
 124                 }
 125                 else if(PT_REGS_SYSCALL_RET(regs) == -ERESTART_RESTARTBLOCK){
 126                         PT_REGS_SYSCALL_RET(regs) = __NR_restart_syscall;
 127                         PT_REGS_RESTART_SYSCALL(regs);
 128                 }
 129         }
 130
 131         /* This closes a way to execute a system call on the host.  If
 132          * you set a breakpoint on a system call instruction and singlestep
 133          * from it, the tracing thread used to PTRACE_SINGLESTEP the process
 134          * rather than PTRACE_SYSCALL it, allowing the system call to execute
 135          * on the host.  The tracing thread will check this flag and
 136          * PTRACE_SYSCALL if necessary.
 137          */
 138         if(current->ptrace & PT_DTRACE)
 139                 current->thread.singlestep_syscall =
 140                         is_syscall(PT_REGS_IP(&current->thread.regs));
 141         return(handled_sig);
 142 }
 143
 144 int do_signal(void)
 145 {
 146         return(kern_do_signal(&current->thread.regs, &current->blocked));
 147 }
 148
 149 /*
 150  * Atomically swap in the new signal mask, and wait for a signal.
 151  */
 152 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 153 {
 154         sigset_t saveset;
 155
 156         mask &= _BLOCKABLE;
 157         spin_lock_irq(&current->sighand->siglock);
 158         saveset = current->blocked;
 159         siginitset(&current->blocked, mask);
 160         recalc_sigpending();
 161         spin_unlock_irq(&current->sighand->siglock);
 162
 163         PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
 164         while (1) {
 165                 current->state = TASK_INTERRUPTIBLE;
 166                 schedule();
 167                 if(kern_do_signal(&current->thread.regs, &saveset))
 168                         return(-EINTR);
 169         }
 170 }
 171
 172 long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
 173 {
 174         sigset_t saveset, newset;
 175
 176         /* XXX: Don't preclude handling different sized sigset_t's.  */
 177         if (sigsetsize != sizeof(sigset_t))
 178                 return -EINVAL;
 179
 180         if (copy_from_user(&newset, unewset, sizeof(newset)))
 181                 return -EFAULT;
 182         sigdelsetmask(&newset, ~_BLOCKABLE);
 183
 184         spin_lock_irq(&current->sighand->siglock);
 185         saveset = current->blocked;
 186         current->blocked = newset;
 187         recalc_sigpending();
 188         spin_unlock_irq(&current->sighand->siglock);
 189
 190         PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
 191         while (1) {
 192                 current->state = TASK_INTERRUPTIBLE;
 193                 schedule();
 194                 if (kern_do_signal(&current->thread.regs, &saveset))
 195                         return(-EINTR);
 196         }
 197 }
 198
 199 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 200 {
 201         return(do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs)));
 202 }
 203
 204 /*
 205  * Overrides for Emacs so that we follow Linus's tabbing style.
 206  * Emacs will notice this stuff at the end of the file and automatically
 207  * adjust the settings for this buffer only.  This must remain at the end
 208  * of the file.
 209  * ---------------------------------------------------------------------------
 210  * Local variables:
 211  * c-file-style: "linux"
 212  * End:
 213  */