arch/um/kernel/signal_user.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdio.h>
   7 #include <unistd.h>
   8 #include <stdlib.h>
   9 #include <signal.h>
  10 #include <errno.h>
  11 #include <stdarg.h>
  12 #include <string.h>
  13 #include <sys/mman.h>
  14 #include "user_util.h"
  15 #include "kern_util.h"
  16 #include "user.h"
  17 #include "signal_user.h"
  18 #include "signal_kern.h"
  19 #include "sysdep/sigcontext.h"
  20 #include "sigcontext.h"
  21
  22 void set_sigstack(void *sig_stack, int size)
  23 {
  24         stack_t stack = ((stack_t) { .ss_flags  = 0,
  25                                      .ss_sp     = (__ptr_t) sig_stack,
  26                                      .ss_size   = size - sizeof(void *) });
  27
  28         if(sigaltstack(&stack, NULL) != 0)
  29                 panic("enabling signal stack failed, errno = %d\n", errno);
  30 }
  31
  32 void set_handler(int sig, void (*handler)(int), int flags, ...)
  33 {
  34         struct sigaction action;
  35         va_list ap;
  36         int mask;
  37
  38         va_start(ap, flags);
  39         action.sa_handler = handler;
  40         sigemptyset(&action.sa_mask);
  41         while((mask = va_arg(ap, int)) != -1){
  42                 sigaddset(&action.sa_mask, mask);
  43         }
  44         action.sa_flags = flags;
  45         action.sa_restorer = NULL;
  46         if(sigaction(sig, &action, NULL) < 0)
  47                 panic("sigaction failed");
  48 }
  49
  50 int change_sig(int signal, int on)
  51 {
  52         sigset_t sigset, old;
  53
  54         sigemptyset(&sigset);
  55         sigaddset(&sigset, signal);
  56         sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
  57         return(!sigismember(&old, signal));
  58 }
  59
  60 static void change_signals(int type)
  61 {
  62         sigset_t mask;
  63
  64         sigemptyset(&mask);
  65         sigaddset(&mask, SIGVTALRM);
  66         sigaddset(&mask, SIGALRM);
  67         sigaddset(&mask, SIGIO);
  68         sigaddset(&mask, SIGPROF);
  69         if(sigprocmask(type, &mask, NULL) < 0)
  70                 panic("Failed to change signal mask - errno = %d", errno);
  71 }
  72
  73 void block_signals(void)
  74 {
  75         change_signals(SIG_BLOCK);
  76 }
  77
  78 void unblock_signals(void)
  79 {
  80         change_signals(SIG_UNBLOCK);
  81 }
  82
  83 /* These are the asynchronous signals.  SIGVTALRM and SIGARLM are handled
  84  * together under SIGVTALRM_BIT.  SIGPROF is excluded because we want to
  85  * be able to profile all of UML, not just the non-critical sections.  If
  86  * profiling is not thread-safe, then that is not my problem.  We can disable
  87  * profiling when SMP is enabled in that case.
  88  */
  89 #define SIGIO_BIT 0
  90 #define SIGVTALRM_BIT 1
  91
  92 static int enable_mask(sigset_t *mask)
  93 {
  94         int sigs;
  95
  96         sigs = sigismember(mask, SIGIO) ? 0 : 1 << SIGIO_BIT;
  97         sigs |= sigismember(mask, SIGVTALRM) ? 0 : 1 << SIGVTALRM_BIT;
  98         sigs |= sigismember(mask, SIGALRM) ? 0 : 1 << SIGVTALRM_BIT;
  99         return(sigs);
 100 }
 101
 102 int get_signals(void)
 103 {
 104         sigset_t mask;
 105
 106         if(sigprocmask(SIG_SETMASK, NULL, &mask) < 0)
 107                 panic("Failed to get signal mask");
 108         return(enable_mask(&mask));
 109 }
 110
 111 int set_signals(int enable)
 112 {
 113         sigset_t mask;
 114         int ret;
 115
 116         sigemptyset(&mask);
 117         if(enable & (1 << SIGIO_BIT))
 118                 sigaddset(&mask, SIGIO);
 119         if(enable & (1 << SIGVTALRM_BIT)){
 120                 sigaddset(&mask, SIGVTALRM);
 121                 sigaddset(&mask, SIGALRM);
 122         }
 123
 124         /* This is safe - sigprocmask is guaranteed to copy locally the
 125          * value of new_set, do his work and then, at the end, write to
 126          * old_set.
 127          */
 128         if(sigprocmask(SIG_UNBLOCK, &mask, &mask) < 0)
 129                 panic("Failed to enable signals");
 130         ret = enable_mask(&mask);
 131         sigemptyset(&mask);
 132         if((enable & (1 << SIGIO_BIT)) == 0)
 133                 sigaddset(&mask, SIGIO);
 134         if((enable & (1 << SIGVTALRM_BIT)) == 0){
 135                 sigaddset(&mask, SIGVTALRM);
 136                 sigaddset(&mask, SIGALRM);
 137         }
 138         if(sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
 139                 panic("Failed to block signals");
 140
 141         return(ret);
 142 }
 143
 144 /*
 145  * Overrides for Emacs so that we follow Linus's tabbing style.
 146  * Emacs will notice this stuff at the end of the file and automatically
 147  * adjust the settings for this buffer only.  This must remain at the end
 148  * of the file.
 149  * ---------------------------------------------------------------------------
 150  * Local variables:
 151  * c-file-style: "linux"
 152  * End:
 153  */