bsd/dev/i386/unix_signal.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1992 NeXT, Inc.
  27  *
  28  * HISTORY
  29  * 13 May 1992 ? at NeXT
  30  *      Created.
  31  */
  32
  33 #include <mach/mach_types.h>
  34 #include <mach/exception.h>
  35
  36 #include <kern/thread.h>
  37 #include <kern/thread_act.h>
  38
  39 #include <sys/param.h>
  40 #include <sys/proc.h>
  41 #include <sys/user.h>
  42
  43 #include <i386/psl.h>
  44
  45 #include <mach/i386/thread_status.h>
  46 #include <dev/i386/sel_inline.h>
  47
  48
  49 /*
  50  * FIXME.. should be included from mach_kernel/i386/seg.h
  51  */
  52
  53 #define USER_CS 0x17
  54 #define USER_DS 0x1f
  55
  56 #define UDATA_SEL       USER_DS
  57 #define UCODE_SEL       USER_CS
  58
  59 #define valid_user_code_selector(x)     (TRUE)
  60 #define valid_user_data_selector(x)     (TRUE)
  61 #define valid_user_stack_selector(x)    (TRUE)
  62
  63
  64 #define NULL_SEG        0
  65
  66 /*
  67  * Send an interrupt to process.
  68  *
  69  * Stack is set up to allow sigcode stored
  70  * in u. to call routine, followed by chmk
  71  * to sigreturn routine below.  After sigreturn
  72  * resets the signal mask, the stack, the frame
  73  * pointer, and the argument pointer, it returns
  74  * to the user specified pc, psl.
  75  */
  76
  77 void
  78 sendsig(p, catcher, sig, mask, code)
  79         struct proc *p;
  80         sig_t catcher;
  81         int sig, mask;
  82         u_long code;
  83 {
  84         struct sigframe {
  85                 int                     retaddr;
  86                 sig_t                   catcher;
  87                 int                     sigstyle;
  88                 int                     sig;
  89                 int                     code;
  90                 struct sigcontext *     scp;
  91         } frame, *fp;
  92         struct sigcontext               context, *scp;
  93         struct sigacts *ps = p->p_sigacts;
  94         int oonstack;
  95         thread_t thread = current_thread();
  96         thread_act_t th_act = current_act();
  97         struct uthread * ut;
  98         struct i386_saved_state * saved_state = get_user_regs(th_act);
  99         sig_t trampact;
 100
 101         ut = get_bsdthread_info(th_act);
 102         oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;
 103         if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
 104                 (ps->ps_sigonstack & sigmask(sig))) {
 105                         scp = ((struct sigcontext *)ps->ps_sigstk.ss_sp) - 1;
 106                         ps->ps_sigstk.ss_flags |= SA_ONSTACK;
 107         } else
 108                 scp = ((struct sigcontext *)saved_state->uesp) - 1;
 109         fp = ((struct sigframe *)scp) - 1;
 110
 111         /*
 112          * Build the argument list for the signal handler.
 113          */
 114
 115         trampact = ps->ps_trampact[sig];
 116         /* Handler should call sigreturn to get out of it */
 117         frame.retaddr = 0xffffffff;
 118         frame.catcher = catcher;
 119         frame.sigstyle = 1;
 120         frame.sig = sig;
 121
 122         if (sig == SIGILL || sig == SIGFPE) {
 123                 frame.code = code;
 124         } else
 125                 frame.code = 0;
 126         frame.scp = scp;
 127         if (copyout((caddr_t)&frame, (caddr_t)fp, sizeof (frame)))
 128                 goto bad;
 129
 130 #if     PC_SUPPORT
 131         {
 132         PCcontext_t     context = threadPCContext(thread);
 133
 134         if (context && context->running) {
 135                 oonstack |= 02;
 136                 context->running = FALSE;
 137         }
 138         }
 139 #endif
 140         /*
 141          * Build the signal context to be used by sigreturn.
 142          */
 143         context.sc_onstack = oonstack;
 144         context.sc_mask = mask;
 145         context.sc_eax = saved_state->eax;
 146         context.sc_ebx = saved_state->ebx;
 147         context.sc_ecx = saved_state->ecx;
 148         context.sc_edx = saved_state->edx;
 149         context.sc_edi = saved_state->edi;
 150         context.sc_esi = saved_state->esi;
 151         context.sc_ebp = saved_state->ebp;
 152         context.sc_esp = saved_state->uesp;
 153         context.sc_ss = saved_state->ss;
 154         context.sc_eflags = saved_state->efl;
 155         context.sc_eip = saved_state->eip;
 156         context.sc_cs = saved_state->cs;
 157         if (saved_state->efl & EFL_VM) {
 158                 context.sc_ds = saved_state->v86_segs.v86_ds;
 159                 context.sc_es = saved_state->v86_segs.v86_es;
 160                 context.sc_fs = saved_state->v86_segs.v86_fs;
 161                 context.sc_gs = saved_state->v86_segs.v86_gs;
 162
 163                 saved_state->efl &= ~EFL_VM;
 164         } else {
 165                 context.sc_ds = saved_state->ds;
 166                 context.sc_es = saved_state->es;
 167                 context.sc_fs = saved_state->fs;
 168                 context.sc_gs = saved_state->gs;
 169         }
 170         if (copyout((caddr_t)&context, (caddr_t)scp, sizeof (context)))
 171                 goto bad;
 172
 173         saved_state->eip = (unsigned int)trampact;
 174         saved_state->cs = UCODE_SEL;
 175
 176         saved_state->uesp = (unsigned int)fp;
 177         saved_state->ss = UDATA_SEL;
 178
 179         saved_state->ds = UDATA_SEL;
 180         saved_state->es = UDATA_SEL;
 181         saved_state->fs = NULL_SEG;
 182         saved_state->gs = NULL_SEG;
 183         return;
 184
 185 bad:
 186         SIGACTION(p, SIGILL) = SIG_DFL;
 187         sig = sigmask(SIGILL);
 188         p->p_sigignore &= ~sig;
 189         p->p_sigcatch &= ~sig;
 190         ut->uu_sigmask &= ~sig;
 191         /* sendsig is called with signal lock held */
 192         psignal_lock(p, SIGILL, 0);
 193         return;
 194 }
 195
 196 /*
 197  * System call to cleanup state after a signal
 198  * has been taken.  Reset signal mask and
 199  * stack state from context left by sendsig (above).
 200  * Return to previous pc and psl as specified by
 201  * context left by sendsig. Check carefully to
 202  * make sure that the user has not modified the
 203  * psl to gain improper priviledges or to cause
 204  * a machine fault.
 205  */
 206 struct sigreturn_args {
 207         struct sigcontext *sigcntxp;
 208 };
 209 /* ARGSUSED */
 210 int
 211 sigreturn(p, uap, retval)
 212         struct proc *p;
 213         struct sigreturn_args *uap;
 214         int *retval;
 215 {
 216     struct sigcontext           context;
 217     thread_t                    thread = current_thread();
 218     thread_act_t                th_act = current_act();
 219         int error;
 220     struct i386_saved_state*    saved_state = get_user_regs(th_act);
 221         struct uthread * ut;
 222
 223
 224
 225     if (saved_state == NULL)
 226         return EINVAL;
 227
 228     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context,
 229                                                 sizeof (context)))
 230                                         return(error);
 231         ut = (struct uthread *)get_bsdthread_info(th_act);
 232
 233     if (context.sc_onstack & 01)
 234                         p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
 235         else
 236                 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
 237         ut->uu_sigmask = context.sc_mask &~ sigcantmask;
 238         if(ut->uu_siglist & ~ut->uu_sigmask)
 239                 signal_setast(current_act());
 240     saved_state->eax = context.sc_eax;
 241     saved_state->ebx = context.sc_ebx;
 242     saved_state->ecx = context.sc_ecx;
 243     saved_state->edx = context.sc_edx;
 244     saved_state->edi = context.sc_edi;
 245     saved_state->esi = context.sc_esi;
 246     saved_state->ebp = context.sc_ebp;
 247     saved_state->uesp = context.sc_esp;
 248     saved_state->ss = context.sc_ss;
 249     saved_state->efl = context.sc_eflags;
 250     saved_state->efl &= ~EFL_USERCLR;
 251     saved_state->efl |= EFL_USERSET;
 252     saved_state->eip = context.sc_eip;
 253     saved_state->cs = context.sc_cs;
 254
 255     if (context.sc_eflags & EFL_VM) {
 256         saved_state->ds = NULL_SEG;
 257         saved_state->es = NULL_SEG;
 258         saved_state->fs = NULL_SEG;
 259         saved_state->gs = NULL_SEG;
 260         saved_state->v86_segs.v86_ds = context.sc_ds;
 261         saved_state->v86_segs.v86_es = context.sc_es;
 262         saved_state->v86_segs.v86_fs = context.sc_fs;
 263         saved_state->v86_segs.v86_gs = context.sc_gs;
 264
 265         saved_state->efl |= EFL_VM;
 266     }
 267     else {
 268         saved_state->ds = context.sc_ds;
 269         saved_state->es = context.sc_es;
 270         saved_state->fs = context.sc_fs;
 271         saved_state->gs = context.sc_gs;
 272     }
 273
 274 #if     PC_SUPPORT
 275     if (context.sc_onstack & 02) {
 276         PCcontext_t     context = threadPCContext(thread);
 277
 278         if (context)
 279             context->running = TRUE;
 280     }
 281 #endif
 282
 283         return (EJUSTRETURN);
 284 }
 285
 286 /*
 287  * machine_exception() performs MD translation
 288  * of a mach exception to a unix signal and code.
 289  */
 290
 291 boolean_t
 292 machine_exception(
 293     int         exception,
 294     int         code,
 295     int         subcode,
 296     int         *unix_signal,
 297     int         *unix_code
 298 )
 299 {
 300
 301     switch(exception) {
 302
 303     case EXC_BAD_INSTRUCTION:
 304         *unix_signal = SIGILL;
 305         *unix_code = code;
 306         break;
 307
 308     case EXC_ARITHMETIC:
 309         *unix_signal = SIGFPE;
 310         *unix_code = code;
 311         break;
 312
 313     default:
 314         return(FALSE);
 315     }
 316
 317     return(TRUE);
 318 }