linux-user/signal.c

   1 /*
   2  *  Emulation of Linux signal handling
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <stdarg.h>
  23 #include <signal.h>
  24 #include <sys/ucontext.h>
  25
  26 /* Algorithm strongly inspired from em86 : we queue the signals so
  27    that we can handle them at precise points in the emulated code. */
  28
  29 struct emulated_sigaction {
  30     struct target_sigaction sa;
  31     int nb_pending;
  32     struct target_siginfo info;
  33 };
  34
  35 struct emulated_sigaction sigact_table[NSIG];
  36 int signal_pending;
  37
  38 static inline int host_to_target_signal(int sig)
  39 {
  40     return sig;
  41 }
  42
  43 static inline int target_to_host_signal(int sig)
  44 {
  45     return sig;
  46 }
  47
  48 void signal_init(void)
  49 {
  50     struct sigaction act;
  51     int i;
  52
  53     /* set all host signal handlers */
  54     sigemptyset(&act.sa_mask);
  55     act.sa_flags = SA_SIGINFO;
  56     act.sa_sigaction = host_signal_handler;
  57     for(i = 1; i < NSIG; i++) {
  58         sigaction(i, &sa, NULL);
  59     }
  60
  61     memset(sigact_table, 0, sizeof(sigact_table));
  62 }
  63
  64 static void host_signal_handler(int host_signum, siginfo_t *info,
  65                                 void *puc)
  66 {
  67     struct ucontext *uc = puc;
  68     int signum;
  69     /* get target signal number */
  70     signum = host_to_target(host_signum);
  71     if (signum >= TARGET_NSIG)
  72         return;
  73     /* we save the old mask */
  74
  75
  76 }
  77
  78
  79 void process_pending_signals(void)
  80 {
  81     int signum;
  82     target_ulong _sa_handler;
  83
  84     struct emulated_sigaction *esig;
  85
  86     if (!signal_pending)
  87         return;
  88
  89     esig = sigact_table;
  90     for(signum = 1; signum < TARGET_NSIG; signum++) {
  91         if (esig->nb_pending != 0)
  92             goto handle_signal;
  93         esig++;
  94     }
  95     /* if no signal is pending, just return */
  96     signal_pending = 0;
  97     return;
  98  handle_signal:
  99     _sa_handler = esig->sa._sa_handler;
 100     if (_sa_handler == TARGET_SIG_DFL) {
 101         /* default handling
 102     }
 103
 104
 105 }