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
  53 #define UDATA_SEL       USER_DS
  54 #define UCODE_SEL       USER_CS
  55
  56 #define valid_user_code_selector(x)     (TRUE)
  57 #define valid_user_data_selector(x)     (TRUE)
  58 #define valid_user_stack_selector(x)    (TRUE)
  59
  60
  61 #define NULL_SEG        0
  62
  63 /*
  64  * Send an interrupt to process.
  65  *
  66  * Stack is set up to allow sigcode stored
  67  * in u. to call routine, followed by chmk
  68  * to sigreturn routine below.  After sigreturn
  69  * resets the signal mask, the stack, the frame
  70  * pointer, and the argument pointer, it returns
  71  * to the user specified pc, psl.
  72  */
  73
  74 void
  75 sendsig(p, catcher, sig, mask, code)
  76         struct proc *p;
  77         sig_t catcher;
  78         int sig, mask;
  79         u_long code;
  80 {
  81     struct sigframe {
  82         int                     retaddr;
  83         int                     sig;
  84         int                     code;
  85         struct sigcontext *     scp;
  86     }                           frame, *fp;
  87     struct sigcontext           context, *scp;
  88         struct sigacts *ps = p->p_sigacts;
  89     int                         oonstack;
  90     thread_t                    thread = current_thread();
  91     thread_act_t                th_act = current_act();
  92     struct i386_saved_state *   saved_state = get_user_regs(th_act);
  93
  94         oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;
  95     if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
  96                 (ps->ps_sigonstack & sigmask(sig))) {
  97                 scp = ((struct sigcontext *)ps->ps_sigstk.ss_sp) - 1;
  98                         ps->ps_sigstk.ss_flags |= SA_ONSTACK;
  99     } else
 100             scp = ((struct sigcontext *)saved_state->uesp) - 1;
 101     fp = ((struct sigframe *)scp) - 1;
 102
 103     /*
 104      * Build the argument list for the signal handler.
 105      */
 106
 107     frame.retaddr = 0xffffffff; /* Handler should call sigreturn to get out of it */
 108     frame.sig = sig;
 109
 110     if (sig == SIGILL || sig == SIGFPE) {
 111             frame.code = code;
 112     } else
 113             frame.code = 0;
 114     frame.scp = scp;
 115     if (copyout((caddr_t)&frame, (caddr_t)fp, sizeof (frame)))
 116         goto bad;
 117
 118 #if     PC_SUPPORT
 119     {
 120         PCcontext_t     context = threadPCContext(thread);
 121
 122         if (context && context->running) {
 123             oonstack |= 02;
 124             context->running = FALSE;
 125         }
 126     }
 127 #endif
 128     /*
 129      * Build the signal context to be used by sigreturn.
 130      */
 131     context.sc_onstack = oonstack;
 132     context.sc_mask = mask;
 133     context.sc_eax = saved_state->eax;
 134     context.sc_ebx = saved_state->ebx;
 135     context.sc_ecx = saved_state->ecx;
 136     context.sc_edx = saved_state->edx;
 137     context.sc_edi = saved_state->edi;
 138     context.sc_esi = saved_state->esi;
 139     context.sc_ebp = saved_state->ebp;
 140     context.sc_esp = saved_state->uesp;
 141     context.sc_ss = saved_state->ss;
 142     context.sc_eflags = saved_state->efl;
 143     context.sc_eip = saved_state->eip;
 144     context.sc_cs = saved_state->cs;
 145     if (saved_state->efl & EFL_VM) {
 146         context.sc_ds = saved_state->v86_segs.v86_ds;
 147         context.sc_es = saved_state->v86_segs.v86_es;
 148         context.sc_fs = saved_state->v86_segs.v86_fs;
 149         context.sc_gs = saved_state->v86_segs.v86_gs;
 150
 151         saved_state->efl &= ~EFL_VM;
 152     }
 153     else {
 154         context.sc_ds = saved_state->ds;
 155         context.sc_es = saved_state->es;
 156         context.sc_fs = saved_state->fs;
 157         context.sc_gs = saved_state->gs;
 158     }
 159     if (copyout((caddr_t)&context, (caddr_t)scp, sizeof (context)))
 160         goto bad;
 161
 162     saved_state->eip = (unsigned int)catcher;
 163     saved_state->cs = UCODE_SEL;
 164
 165     saved_state->uesp = (unsigned int)fp;
 166     saved_state->ss = UDATA_SEL;
 167
 168     saved_state->ds = UDATA_SEL;
 169     saved_state->es = UDATA_SEL;
 170     saved_state->fs = NULL_SEG;
 171     saved_state->gs = NULL_SEG;
 172     return;
 173
 174 bad:
 175         SIGACTION(p, SIGILL) = SIG_DFL;
 176         sig = sigmask(SIGILL);
 177         p->p_sigignore &= ~sig;
 178         p->p_sigcatch &= ~sig;
 179         p->p_sigmask &= ~sig;
 180         /* sendsig is called with signal lock held */
 181         psignal_lock(p, SIGILL, 0, 1);
 182         return;
 183 }
 184
 185 /*
 186  * System call to cleanup state after a signal
 187  * has been taken.  Reset signal mask and
 188  * stack state from context left by sendsig (above).
 189  * Return to previous pc and psl as specified by
 190  * context left by sendsig. Check carefully to
 191  * make sure that the user has not modified the
 192  * psl to gain improper priviledges or to cause
 193  * a machine fault.
 194  */
 195 struct sigreturn_args {
 196         struct sigcontext *sigcntxp;
 197 };
 198 /* ARGSUSED */
 199 int
 200 sigreturn(p, uap, retval)
 201         struct proc *p;
 202         struct sigreturn_args *uap;
 203         int *retval;
 204 {
 205     struct sigcontext           context;
 206     thread_t                    thread = current_thread();
 207     thread_act_t                th_act = current_act();
 208         int error;
 209     struct i386_saved_state*    saved_state = get_user_regs(th_act);
 210
 211     if (saved_state == NULL)
 212         return EINVAL;
 213
 214     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context,
 215                                                 sizeof (context)))
 216                                         return(error);
 217
 218 #if 0 /*FIXME*/
 219     if ((context.sc_eflags & EFL_VM) == 0 &&
 220            (!valid_user_code_selector(context.sc_cs) ||
 221             !valid_user_data_selector(context.sc_ds) ||
 222             !valid_user_data_selector(context.sc_es) ||
 223             !valid_user_data_selector(context.sc_fs) ||
 224             !valid_user_data_selector(context.sc_gs) ||
 225             !valid_user_stack_selector(context.sc_ss))
 226         )
 227         return(EINVAL);
 228 #endif
 229
 230     if (context.sc_onstack & 01)
 231                         p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
 232         else
 233                 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
 234         p->p_sigmask = context.sc_mask &~ sigcantmask;
 235     saved_state->eax = context.sc_eax;
 236     saved_state->ebx = context.sc_ebx;
 237     saved_state->ecx = context.sc_ecx;
 238     saved_state->edx = context.sc_edx;
 239     saved_state->edi = context.sc_edi;
 240     saved_state->esi = context.sc_esi;
 241     saved_state->ebp = context.sc_ebp;
 242     saved_state->uesp = context.sc_esp;
 243     saved_state->ss = context.sc_ss;
 244     saved_state->efl = context.sc_eflags;
 245     saved_state->efl &= ~EFL_USERCLR;
 246     saved_state->efl |= EFL_USERSET;
 247     saved_state->eip = context.sc_eip;
 248     saved_state->cs = context.sc_cs;
 249
 250     if (context.sc_eflags & EFL_VM) {
 251         saved_state->ds = NULL_SEG;
 252         saved_state->es = NULL_SEG;
 253         saved_state->fs = NULL_SEG;
 254         saved_state->gs = NULL_SEG;
 255         saved_state->v86_segs.v86_ds = context.sc_ds;
 256         saved_state->v86_segs.v86_es = context.sc_es;
 257         saved_state->v86_segs.v86_fs = context.sc_fs;
 258         saved_state->v86_segs.v86_gs = context.sc_gs;
 259
 260         saved_state->efl |= EFL_VM;
 261     }
 262     else {
 263         saved_state->ds = context.sc_ds;
 264         saved_state->es = context.sc_es;
 265         saved_state->fs = context.sc_fs;
 266         saved_state->gs = context.sc_gs;
 267     }
 268
 269 #if     PC_SUPPORT
 270     if (context.sc_onstack & 02) {
 271         PCcontext_t     context = threadPCContext(thread);
 272
 273         if (context)
 274             context->running = TRUE;
 275     }
 276 #endif
 277
 278         return (EJUSTRETURN);
 279 }
 280
 281 /*
 282  * machine_exception() performs MD translation
 283  * of a mach exception to a unix signal and code.
 284  */
 285
 286 boolean_t
 287 machine_exception(
 288     int         exception,
 289     int         code,
 290     int         subcode,
 291     int         *unix_signal,
 292     int         *unix_code
 293 )
 294 {
 295
 296     switch(exception) {
 297
 298     case EXC_BAD_INSTRUCTION:
 299         *unix_signal = SIGILL;
 300         *unix_code = code;
 301         break;
 302
 303     case EXC_ARITHMETIC:
 304         *unix_signal = SIGFPE;
 305         *unix_code = code;
 306         break;
 307
 308     default:
 309         return(FALSE);
 310     }
 311
 312     return(TRUE);
 313 }