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  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1992 NeXT, Inc.
  24  *
  25  * HISTORY
  26  * 13 May 1992 ? at NeXT
  27  *      Created.
  28  */
  29
  30 #include <mach/mach_types.h>
  31 #include <mach/exception.h>
  32
  33 #include <kern/thread.h>
  34 #include <kern/thread_act.h>
  35
  36 #include <sys/param.h>
  37 #include <sys/proc.h>
  38 #include <sys/user.h>
  39
  40 #include <i386/psl.h>
  41
  42 #include <mach/i386/thread_status.h>
  43 #include <dev/i386/sel_inline.h>
  44
  45
  46 /*
  47  * FIXME.. should be included from mach_kernel/i386/seg.h
  48  */
  49
  50 #define USER_CS 0x17
  51 #define USER_DS 0x1f
  52 #define USER_CTHREAD 0x27
  53
  54 #define UDATA_SEL       USER_DS
  55 #define UCODE_SEL       USER_CS
  56 #define UCTHREAD_SEL    USER_CTHREAD
  57
  58 #define valid_user_code_selector(x)     (TRUE)
  59 #define valid_user_data_selector(x)     (TRUE)
  60 #define valid_user_stack_selector(x)    (TRUE)
  61
  62
  63 #define NULL_SEG        0
  64
  65 /* Signal handler flavors supported */
  66 /* These defns should match the Libc implmn */
  67 #define UC_TRAD                 1
  68
  69 /*
  70  * Send an interrupt to process.
  71  *
  72  * Stack is set up to allow sigcode stored
  73  * in u. to call routine, followed by chmk
  74  * to sigreturn routine below.  After sigreturn
  75  * resets the signal mask, the stack, the frame
  76  * pointer, and the argument pointer, it returns
  77  * to the user specified pc, psl.
  78  */
  79
  80 void
  81 sendsig(p, catcher, sig, mask, code)
  82         struct proc *p;
  83         sig_t catcher;
  84         int sig, mask;
  85         u_long code;
  86 {
  87         struct sigframe {
  88                 int                     retaddr;
  89                 sig_t                   catcher;
  90                 int                     sigstyle;
  91                 int                     sig;
  92                 int                     code;
  93                 struct sigcontext *     scp;
  94         } frame, *fp;
  95         struct sigcontext               context, *scp;
  96         struct sigacts *ps = p->p_sigacts;
  97         int oonstack;
  98         thread_t thread = current_thread();
  99         thread_act_t th_act = current_act();
 100         struct uthread * ut;
 101         struct i386_saved_state * saved_state = (struct i386_saved_state *)
 102                                                         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 = USER_CTHREAD;
 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 = (struct i386_saved_state*)
 225                                                         get_user_regs(th_act);
 226         struct uthread * ut;
 227
 228
 229
 230     if (saved_state == NULL)
 231         return EINVAL;
 232
 233     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context,
 234                                                 sizeof (context)))
 235                                         return(error);
 236         ut = (struct uthread *)get_bsdthread_info(th_act);
 237
 238     if (context.sc_onstack & 01)
 239                         p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
 240         else
 241                 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
 242         ut->uu_sigmask = context.sc_mask &~ sigcantmask;
 243         if(ut->uu_siglist & ~ut->uu_sigmask)
 244                 signal_setast(current_act());
 245     saved_state->eax = context.sc_eax;
 246     saved_state->ebx = context.sc_ebx;
 247     saved_state->ecx = context.sc_ecx;
 248     saved_state->edx = context.sc_edx;
 249     saved_state->edi = context.sc_edi;
 250     saved_state->esi = context.sc_esi;
 251     saved_state->ebp = context.sc_ebp;
 252     saved_state->uesp = context.sc_esp;
 253     saved_state->ss = context.sc_ss;
 254     saved_state->efl = context.sc_eflags;
 255     saved_state->efl &= ~EFL_USERCLR;
 256     saved_state->efl |= EFL_USERSET;
 257     saved_state->eip = context.sc_eip;
 258     saved_state->cs = context.sc_cs;
 259
 260     if (context.sc_eflags & EFL_VM) {
 261         saved_state->ds = NULL_SEG;
 262         saved_state->es = NULL_SEG;
 263         saved_state->fs = NULL_SEG;
 264         saved_state->gs = NULL_SEG;
 265         saved_state->v86_segs.v86_ds = context.sc_ds;
 266         saved_state->v86_segs.v86_es = context.sc_es;
 267         saved_state->v86_segs.v86_fs = context.sc_fs;
 268         saved_state->v86_segs.v86_gs = context.sc_gs;
 269
 270         saved_state->efl |= EFL_VM;
 271     }
 272     else {
 273         saved_state->ds = context.sc_ds;
 274         saved_state->es = context.sc_es;
 275         saved_state->fs = context.sc_fs;
 276         saved_state->gs = context.sc_gs;
 277     }
 278
 279 #if     PC_SUPPORT
 280     if (context.sc_onstack & 02) {
 281         PCcontext_t     context = threadPCContext(thread);
 282
 283         if (context)
 284             context->running = TRUE;
 285     }
 286 #endif
 287
 288         return (EJUSTRETURN);
 289 }
 290
 291 /*
 292  * machine_exception() performs MD translation
 293  * of a mach exception to a unix signal and code.
 294  */
 295
 296 boolean_t
 297 machine_exception(
 298     int         exception,
 299     int         code,
 300     int         subcode,
 301     int         *unix_signal,
 302     int         *unix_code
 303 )
 304 {
 305
 306     switch(exception) {
 307
 308     case EXC_BAD_INSTRUCTION:
 309         *unix_signal = SIGILL;
 310         *unix_code = code;
 311         break;
 312
 313     case EXC_ARITHMETIC:
 314         *unix_signal = SIGFPE;
 315         *unix_code = code;
 316         break;
 317
 318     default:
 319         return(FALSE);
 320     }
 321
 322     return(TRUE);
 323 }