arch/um/os-Linux/signal.c

   1 /*
   2  * Copyright (C) 2004 PathScale, Inc
   3  * Licensed under the GPL
   4  */
   5
   6 #include <signal.h>
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <stdlib.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_kern.h"
  18 #include "sysdep/sigcontext.h"
  19 #include "sysdep/signal.h"
  20 #include "sigcontext.h"
  21 #include "time_user.h"
  22 #include "mode.h"
  23
  24 void sig_handler(ARCH_SIGHDLR_PARAM)
  25 {
  26         struct sigcontext *sc;
  27
  28         ARCH_GET_SIGCONTEXT(sc, sig);
  29         CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
  30                          sig, sc);
  31 }
  32
  33 extern int timer_irq_inited;
  34
  35 void alarm_handler(ARCH_SIGHDLR_PARAM)
  36 {
  37         struct sigcontext *sc;
  38
  39         ARCH_GET_SIGCONTEXT(sc, sig);
  40         if(!timer_irq_inited) return;
  41
  42         if(sig == SIGALRM)
  43                 switch_timers(0);
  44
  45         CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
  46                          sig, sc);
  47
  48         if(sig == SIGALRM)
  49                 switch_timers(1);
  50 }
  51
  52 void set_sigstack(void *sig_stack, int size)
  53 {
  54         stack_t stack = ((stack_t) { .ss_flags  = 0,
  55                                      .ss_sp     = (__ptr_t) sig_stack,
  56                                      .ss_size   = size - sizeof(void *) });
  57
  58         if(sigaltstack(&stack, NULL) != 0)
  59                 panic("enabling signal stack failed, errno = %d\n", errno);
  60 }
  61
  62 void remove_sigstack(void)
  63 {
  64         stack_t stack = ((stack_t) { .ss_flags  = SS_DISABLE,
  65                                      .ss_sp     = NULL,
  66                                      .ss_size   = 0 });
  67
  68         if(sigaltstack(&stack, NULL) != 0)
  69                 panic("disabling signal stack failed, errno = %d\n", errno);
  70 }
  71
  72 void set_handler(int sig, void (*handler)(int), int flags, ...)
  73 {
  74         struct sigaction action;
  75         va_list ap;
  76         int mask;
  77
  78         va_start(ap, flags);
  79         action.sa_handler = handler;
  80         sigemptyset(&action.sa_mask);
  81         while((mask = va_arg(ap, int)) != -1){
  82                 sigaddset(&action.sa_mask, mask);
  83         }
  84         va_end(ap);
  85         action.sa_flags = flags;
  86         action.sa_restorer = NULL;
  87         if(sigaction(sig, &action, NULL) < 0)
  88                 panic("sigaction failed");
  89 }
  90
  91 int change_sig(int signal, int on)
  92 {
  93         sigset_t sigset, old;
  94
  95         sigemptyset(&sigset);
  96         sigaddset(&sigset, signal);
  97         sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
  98         return(!sigismember(&old, signal));
  99 }
 100
 101 /* Both here and in set/get_signal we don't touch SIGPROF, because we must not
 102  * disable profiling; it's safe because the profiling code does not interact
 103  * with the kernel code at all.*/
 104
 105 static void change_signals(int type)
 106 {
 107         sigset_t mask;
 108
 109         sigemptyset(&mask);
 110         sigaddset(&mask, SIGVTALRM);
 111         sigaddset(&mask, SIGALRM);
 112         sigaddset(&mask, SIGIO);
 113         if(sigprocmask(type, &mask, NULL) < 0)
 114                 panic("Failed to change signal mask - errno = %d", errno);
 115 }
 116
 117 void block_signals(void)
 118 {
 119         change_signals(SIG_BLOCK);
 120 }
 121
 122 void unblock_signals(void)
 123 {
 124         change_signals(SIG_UNBLOCK);
 125 }
 126
 127 /* These are the asynchronous signals.  SIGVTALRM and SIGARLM are handled
 128  * together under SIGVTALRM_BIT.  SIGPROF is excluded because we want to
 129  * be able to profile all of UML, not just the non-critical sections.  If
 130  * profiling is not thread-safe, then that is not my problem.  We can disable
 131  * profiling when SMP is enabled in that case.
 132  */
 133 #define SIGIO_BIT 0
 134 #define SIGVTALRM_BIT 1
 135
 136 static int enable_mask(sigset_t *mask)
 137 {
 138         int sigs;
 139
 140         sigs = sigismember(mask, SIGIO) ? 0 : 1 << SIGIO_BIT;
 141         sigs |= sigismember(mask, SIGVTALRM) ? 0 : 1 << SIGVTALRM_BIT;
 142         sigs |= sigismember(mask, SIGALRM) ? 0 : 1 << SIGVTALRM_BIT;
 143         return(sigs);
 144 }
 145
 146 int get_signals(void)
 147 {
 148         sigset_t mask;
 149
 150         if(sigprocmask(SIG_SETMASK, NULL, &mask) < 0)
 151                 panic("Failed to get signal mask");
 152         return(enable_mask(&mask));
 153 }
 154
 155 int set_signals(int enable)
 156 {
 157         sigset_t mask;
 158         int ret;
 159
 160         sigemptyset(&mask);
 161         if(enable & (1 << SIGIO_BIT))
 162                 sigaddset(&mask, SIGIO);
 163         if(enable & (1 << SIGVTALRM_BIT)){
 164                 sigaddset(&mask, SIGVTALRM);
 165                 sigaddset(&mask, SIGALRM);
 166         }
 167
 168         /* This is safe - sigprocmask is guaranteed to copy locally the
 169          * value of new_set, do his work and then, at the end, write to
 170          * old_set.
 171          */
 172         if(sigprocmask(SIG_UNBLOCK, &mask, &mask) < 0)
 173                 panic("Failed to enable signals");
 174         ret = enable_mask(&mask);
 175         sigemptyset(&mask);
 176         if((enable & (1 << SIGIO_BIT)) == 0)
 177                 sigaddset(&mask, SIGIO);
 178         if((enable & (1 << SIGVTALRM_BIT)) == 0){
 179                 sigaddset(&mask, SIGVTALRM);
 180                 sigaddset(&mask, SIGALRM);
 181         }
 182         if(sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
 183                 panic("Failed to block signals");
 184
 185         return(ret);
 186 }