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 /* Signal handler flavors supported */
  67 /* These defns should match the Libc implmn */
  68 #define UC_TRAD                 1
  69
  70 /*
  71  * Send an interrupt to process.
  72  *
  73  * Stack is set up to allow sigcode stored
  74  * in u. to call routine, followed by chmk
  75  * to sigreturn routine below.  After sigreturn
  76  * resets the signal mask, the stack, the frame
  77  * pointer, and the argument pointer, it returns
  78  * to the user specified pc, psl.
  79  */
  80
  81 void
  82 sendsig(p, catcher, sig, mask, code)
  83         struct proc *p;
  84         sig_t catcher;
  85         int sig, mask;
  86         u_long code;
  87 {
  88         struct sigframe {
  89                 int                     retaddr;
  90                 sig_t                   catcher;
  91                 int                     sigstyle;
  92                 int                     sig;
  93                 int                     code;
  94                 struct sigcontext *     scp;
  95         } frame, *fp;
  96         struct sigcontext               context, *scp;
  97         struct sigacts *ps = p->p_sigacts;
  98         int oonstack;
  99         thread_t thread = current_thread();
 100         thread_act_t th_act = current_act();
 101         struct uthread * ut;
 102         struct i386_saved_state * saved_state = get_user_regs(th_act);
 103         sig_t trampact;
 104
 105         ut = get_bsdthread_info(th_act);
 106         oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;
 107         if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
 108                 (ps->ps_sigonstack & sigmask(sig))) {
 109                         scp = ((struct sigcontext *)ps->ps_sigstk.ss_sp) - 1;
 110                         ps->ps_sigstk.ss_flags |= SA_ONSTACK;
 111         } else
 112                 scp = ((struct sigcontext *)saved_state->uesp) - 1;
 113         fp = ((struct sigframe *)scp) - 1;
 114
 115         /*
 116          * Build the argument list for the signal handler.
 117          */
 118
 119         trampact = ps->ps_trampact[sig];
 120         /* Handler should call sigreturn to get out of it */
 121         frame.retaddr = 0xffffffff;
 122         frame.catcher = catcher;
 123         frame.sigstyle = UC_TRAD;
 124         frame.sig = sig;
 125
 126         if (sig == SIGILL || sig == SIGFPE) {
 127                 frame.code = code;
 128         } else
 129                 frame.code = 0;
 130         frame.scp = scp;
 131         if (copyout((caddr_t)&frame, (caddr_t)fp, sizeof (frame)))
 132                 goto bad;
 133
 134 #if     PC_SUPPORT
 135         {
 136         PCcontext_t     context = threadPCContext(thread);
 137
 138         if (context && context->running) {
 139                 oonstack |= 02;
 140                 context->running = FALSE;
 141         }
 142         }
 143 #endif
 144         /*
 145          * Build the signal context to be used by sigreturn.
 146          */
 147         context.sc_onstack = oonstack;
 148         context.sc_mask = mask;
 149         context.sc_eax = saved_state->eax;
 150         context.sc_ebx = saved_state->ebx;
 151         context.sc_ecx = saved_state->ecx;
 152         context.sc_edx = saved_state->edx;
 153         context.sc_edi = saved_state->edi;
 154         context.sc_esi = saved_state->esi;
 155         context.sc_ebp = saved_state->ebp;
 156         context.sc_esp = saved_state->uesp;
 157         context.sc_ss = saved_state->ss;
 158         context.sc_eflags = saved_state->efl;
 159         context.sc_eip = saved_state->eip;
 160         context.sc_cs = saved_state->cs;
 161         if (saved_state->efl & EFL_VM) {
 162                 context.sc_ds = saved_state->v86_segs.v86_ds;
 163                 context.sc_es = saved_state->v86_segs.v86_es;
 164                 context.sc_fs = saved_state->v86_segs.v86_fs;
 165                 context.sc_gs = saved_state->v86_segs.v86_gs;
 166
 167                 saved_state->efl &= ~EFL_VM;
 168         } else {
 169                 context.sc_ds = saved_state->ds;
 170                 context.sc_es = saved_state->es;
 171                 context.sc_fs = saved_state->fs;
 172                 context.sc_gs = saved_state->gs;
 173         }
 174         if (copyout((caddr_t)&context, (caddr_t)scp, sizeof (context)))
 175                 goto bad;
 176
 177         saved_state->eip = (unsigned int)trampact;
 178         saved_state->cs = UCODE_SEL;
 179
 180         saved_state->uesp = (unsigned int)fp;
 181         saved_state->ss = UDATA_SEL;
 182
 183         saved_state->ds = UDATA_SEL;
 184         saved_state->es = UDATA_SEL;
 185         saved_state->fs = NULL_SEG;
 186         saved_state->gs = NULL_SEG;
 187         return;
 188
 189 bad:
 190         SIGACTION(p, SIGILL) = SIG_DFL;
 191         sig = sigmask(SIGILL);
 192         p->p_sigignore &= ~sig;
 193         p->p_sigcatch &= ~sig;
 194         ut->uu_sigmask &= ~sig;
 195         /* sendsig is called with signal lock held */
 196         psignal_lock(p, SIGILL, 0);
 197         return;
 198 }
 199
 200 /*
 201  * System call to cleanup state after a signal
 202  * has been taken.  Reset signal mask and
 203  * stack state from context left by sendsig (above).
 204  * Return to previous pc and psl as specified by
 205  * context left by sendsig. Check carefully to
 206  * make sure that the user has not modified the
 207  * psl to gain improper priviledges or to cause
 208  * a machine fault.
 209  */
 210 struct sigreturn_args {
 211         struct sigcontext *sigcntxp;
 212 };
 213 /* ARGSUSED */
 214 int
 215 sigreturn(p, uap, retval)
 216         struct proc *p;
 217         struct sigreturn_args *uap;
 218         int *retval;
 219 {
 220     struct sigcontext           context;
 221     thread_t                    thread = current_thread();
 222     thread_act_t                th_act = current_act();
 223         int error;
 224     struct i386_saved_state*    saved_state = get_user_regs(th_act);
 225         struct uthread * ut;
 226
 227
 228
 229     if (saved_state == NULL)
 230         return EINVAL;
 231
 232     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context,
 233                                                 sizeof (context)))
 234                                         return(error);
 235         ut = (struct uthread *)get_bsdthread_info(th_act);
 236
 237     if (context.sc_onstack & 01)
 238                         p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
 239         else
 240                 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
 241         ut->uu_sigmask = context.sc_mask &~ sigcantmask;
 242         if(ut->uu_siglist & ~ut->uu_sigmask)
 243                 signal_setast(current_act());
 244     saved_state->eax = context.sc_eax;
 245     saved_state->ebx = context.sc_ebx;
 246     saved_state->ecx = context.sc_ecx;
 247     saved_state->edx = context.sc_edx;
 248     saved_state->edi = context.sc_edi;
 249     saved_state->esi = context.sc_esi;
 250     saved_state->ebp = context.sc_ebp;
 251     saved_state->uesp = context.sc_esp;
 252     saved_state->ss = context.sc_ss;
 253     saved_state->efl = context.sc_eflags;
 254     saved_state->efl &= ~EFL_USERCLR;
 255     saved_state->efl |= EFL_USERSET;
 256     saved_state->eip = context.sc_eip;
 257     saved_state->cs = context.sc_cs;
 258
 259     if (context.sc_eflags & EFL_VM) {
 260         saved_state->ds = NULL_SEG;
 261         saved_state->es = NULL_SEG;
 262         saved_state->fs = NULL_SEG;
 263         saved_state->gs = NULL_SEG;
 264         saved_state->v86_segs.v86_ds = context.sc_ds;
 265         saved_state->v86_segs.v86_es = context.sc_es;
 266         saved_state->v86_segs.v86_fs = context.sc_fs;
 267         saved_state->v86_segs.v86_gs = context.sc_gs;
 268
 269         saved_state->efl |= EFL_VM;
 270     }
 271     else {
 272         saved_state->ds = context.sc_ds;
 273         saved_state->es = context.sc_es;
 274         saved_state->fs = context.sc_fs;
 275         saved_state->gs = context.sc_gs;
 276     }
 277
 278 #if     PC_SUPPORT
 279     if (context.sc_onstack & 02) {
 280         PCcontext_t     context = threadPCContext(thread);
 281
 282         if (context)
 283             context->running = TRUE;
 284     }
 285 #endif
 286
 287         return (EJUSTRETURN);
 288 }
 289
 290 /*
 291  * machine_exception() performs MD translation
 292  * of a mach exception to a unix signal and code.
 293  */
 294
 295 boolean_t
 296 machine_exception(
 297     int         exception,
 298     int         code,
 299     int         subcode,
 300     int         *unix_signal,
 301     int         *unix_code
 302 )
 303 {
 304
 305     switch(exception) {
 306
 307     case EXC_BAD_INSTRUCTION:
 308         *unix_signal = SIGILL;
 309         *unix_code = code;
 310         break;
 311
 312     case EXC_ARITHMETIC:
 313         *unix_signal = SIGFPE;
 314         *unix_code = code;
 315         break;
 316
 317     default:
 318         return(FALSE);
 319     }
 320
 321     return(TRUE);
 322 }