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
  35 #include <sys/systm.h>
  36 #include <sys/param.h>
  37 #include <sys/proc_internal.h>
  38 #include <sys/user.h>
  39 #include <sys/sysproto.h>
  40 #include <sys/sysent.h>
  41 #include <mach/thread_act.h>    /* for thread_abort_safely */
  42
  43 #include <i386/psl.h>
  44 #include <i386/seg.h>
  45
  46 #include <mach/i386/thread_status.h>
  47
  48 extern struct i386_saved_state *get_user_regs(thread_t);
  49
  50 extern boolean_t valid_user_segment_selectors(uint16_t cs,
  51                                               uint16_t ss,
  52                                               uint16_t ds,
  53                                               uint16_t es,
  54                                               uint16_t fs,
  55                                               uint16_t gs);
  56
  57 /* Forward: */
  58 extern boolean_t machine_exception(int, int, int, int *, int *);
  59
  60 /* Signal handler flavors supported */
  61 /* These defns should match the Libc implmn */
  62 #define UC_TRAD                 1
  63
  64 /*
  65  * Send an interrupt to process.
  66  *
  67  * Stack is set up to allow sigcode stored
  68  * in u. to call routine, followed by chmk
  69  * to sigreturn routine below.  After sigreturn
  70  * resets the signal mask, the stack, the frame
  71  * pointer, and the argument pointer, it returns
  72  * to the user specified pc, psl.
  73  */
  74 void
  75 sendsig(p, catcher, sig, mask, code)
  76         struct proc *p;
  77         user_addr_t catcher;    /* sig_t */
  78         int sig, mask;
  79         u_long code;
  80 {
  81         struct sigframe {
  82                 int                     retaddr;
  83                 sig_t                   catcher;
  84                 int                     sigstyle;
  85                 int                     sig;
  86                 int                     code;
  87                 struct sigcontext *     scp;
  88         } frame, *fp;
  89         struct sigcontext               context, *scp;
  90         struct sigacts *ps = p->p_sigacts;
  91         int oonstack;
  92         thread_t thread = current_thread();
  93         struct uthread * ut;
  94         struct i386_saved_state * saved_state = get_user_regs(thread);
  95         sig_t trampact;
  96
  97         ut = get_bsdthread_info(thread);
  98         oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;
  99         if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
 100                 (ps->ps_sigonstack & sigmask(sig))) {
 101                         scp = ((struct sigcontext *)ps->ps_sigstk.ss_sp) - 1;
 102                         ps->ps_sigstk.ss_flags |= SA_ONSTACK;
 103         } else
 104                 scp = ((struct sigcontext *)saved_state->uesp) - 1;
 105         fp = ((struct sigframe *)scp) - 1;
 106
 107         /*
 108          * Build the argument list for the signal handler.
 109          */
 110
 111         trampact = (sig_t)ps->ps_trampact[sig];
 112         /* Handler should call sigreturn to get out of it */
 113         frame.retaddr = 0xffffffff;
 114         frame.catcher = CAST_DOWN(sig_t,catcher);       /* XXX LP64 */
 115         frame.sigstyle = UC_TRAD;
 116         frame.sig = sig;
 117
 118         if (sig == SIGILL || sig == SIGFPE) {
 119                 frame.code = code;
 120         } else
 121                 frame.code = 0;
 122         frame.scp = scp;
 123         if (copyout((caddr_t)&frame, (user_addr_t)fp, sizeof (frame)))
 124                 goto bad;
 125
 126         /*
 127          * Build the signal context to be used by sigreturn.
 128          */
 129         context.sc_onstack = oonstack;
 130         context.sc_mask = mask;
 131         context.sc_eax = saved_state->eax;
 132         context.sc_ebx = saved_state->ebx;
 133         context.sc_ecx = saved_state->ecx;
 134         context.sc_edx = saved_state->edx;
 135         context.sc_edi = saved_state->edi;
 136         context.sc_esi = saved_state->esi;
 137         context.sc_ebp = saved_state->ebp;
 138         context.sc_esp = saved_state->uesp;
 139         context.sc_ss = saved_state->ss;
 140         context.sc_eflags = saved_state->efl;
 141         context.sc_eip = saved_state->eip;
 142         context.sc_cs = saved_state->cs;
 143         if (saved_state->efl & EFL_VM) {
 144                 context.sc_ds = saved_state->v86_segs.v86_ds;
 145                 context.sc_es = saved_state->v86_segs.v86_es;
 146                 context.sc_fs = saved_state->v86_segs.v86_fs;
 147                 context.sc_gs = saved_state->v86_segs.v86_gs;
 148
 149                 saved_state->efl &= ~EFL_VM;
 150         } else {
 151                 context.sc_ds = saved_state->ds;
 152                 context.sc_es = saved_state->es;
 153                 context.sc_fs = saved_state->fs;
 154                 context.sc_gs = saved_state->gs;
 155         }
 156         if (copyout((caddr_t)&context, (user_addr_t)scp, sizeof (context)))
 157                 goto bad;
 158
 159         saved_state->eip = (unsigned int)trampact;
 160         saved_state->cs = USER_CS;
 161
 162         saved_state->uesp = (unsigned int)fp;
 163         saved_state->ss = USER_DS;
 164
 165         saved_state->ds = USER_DS;
 166         saved_state->es = USER_DS;
 167         saved_state->fs = NULL_SEG;
 168         saved_state->gs = USER_CTHREAD;
 169         return;
 170
 171 bad:
 172         SIGACTION(p, SIGILL) = SIG_DFL;
 173         sig = sigmask(SIGILL);
 174         p->p_sigignore &= ~sig;
 175         p->p_sigcatch &= ~sig;
 176         ut->uu_sigmask &= ~sig;
 177         /* sendsig is called with signal lock held */
 178         psignal_lock(p, SIGILL, 0);
 179         return;
 180 }
 181
 182 /*
 183  * System call to cleanup state after a signal
 184  * has been taken.  Reset signal mask and
 185  * stack state from context left by sendsig (above).
 186  * Return to previous pc and psl as specified by
 187  * context left by sendsig. Check carefully to
 188  * make sure that the user has not modified the
 189  * psl to gain improper priviledges or to cause
 190  * a machine fault.
 191  */
 192 /* ARGSUSED */
 193 int
 194 sigreturn(
 195         struct proc *p,
 196         struct sigreturn_args *uap,
 197         __unused int *retval)
 198 {
 199     struct sigcontext           context;
 200     thread_t                    thread = current_thread();
 201         int error;
 202     struct i386_saved_state*    saved_state = (struct i386_saved_state*)
 203                                                         get_user_regs(thread);
 204         struct uthread * ut;
 205
 206
 207
 208         if (saved_state == NULL)
 209                 return EINVAL;
 210
 211     if ((error = copyin(CAST_USER_ADDR_T(uap->sigcntxp), (void *)&context,
 212                                 sizeof (context))))
 213                 return(error);
 214
 215         /*
 216          * Validate segment selectors.
 217          * Bad values would result in kernel exception at context switch
 218          * back to user mode. If other state is invalid an exception will
 219          * occur in user context.
 220          */
 221         if (!valid_user_segment_selectors(context.sc_cs,
 222                                           context.sc_ss,
 223                                           context.sc_ds,
 224                                           context.sc_es,
 225                                           context.sc_fs,
 226                                           context.sc_gs)) {
 227                 return EINVAL;
 228         }
 229
 230         ut = (struct uthread *)get_bsdthread_info(thread);
 231
 232         if (context.sc_onstack & 01)
 233                 p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
 234         else
 235                 p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
 236
 237         ut->uu_sigmask = context.sc_mask &~ sigcantmask;
 238         if(ut->uu_siglist & ~ut->uu_sigmask)
 239                 signal_setast(thread);
 240
 241         saved_state->eax = context.sc_eax;
 242         saved_state->ebx = context.sc_ebx;
 243         saved_state->ecx = context.sc_ecx;
 244         saved_state->edx = context.sc_edx;
 245         saved_state->edi = context.sc_edi;
 246         saved_state->esi = context.sc_esi;
 247         saved_state->ebp = context.sc_ebp;
 248         saved_state->uesp = context.sc_esp;
 249         saved_state->ss = context.sc_ss;
 250         saved_state->efl = context.sc_eflags;
 251         saved_state->efl &= ~EFL_USERCLR;
 252         saved_state->efl |= EFL_USERSET;
 253         saved_state->eip = context.sc_eip;
 254         saved_state->cs = context.sc_cs;
 255
 256         if (context.sc_eflags & EFL_VM) {
 257                 saved_state->ds = NULL_SEG;
 258                 saved_state->es = NULL_SEG;
 259                 saved_state->fs = NULL_SEG;
 260                 saved_state->gs = NULL_SEG;
 261                 saved_state->v86_segs.v86_ds = context.sc_ds;
 262                 saved_state->v86_segs.v86_es = context.sc_es;
 263                 saved_state->v86_segs.v86_fs = context.sc_fs;
 264                 saved_state->v86_segs.v86_gs = context.sc_gs;
 265
 266                 saved_state->efl |= EFL_VM;
 267         }
 268         else {
 269                 saved_state->ds = context.sc_ds;
 270                 saved_state->es = context.sc_es;
 271                 saved_state->fs = context.sc_fs;
 272                 saved_state->gs = context.sc_gs;
 273         }
 274
 275         return (EJUSTRETURN);
 276 }
 277
 278 /*
 279  * machine_exception() performs MD translation
 280  * of a mach exception to a unix signal and code.
 281  */
 282
 283 boolean_t
 284 machine_exception(
 285     int                 exception,
 286     int                 code,
 287     __unused int        subcode,
 288     int                 *unix_signal,
 289     int                 *unix_code
 290 )
 291 {
 292
 293     switch(exception) {
 294
 295     case EXC_BAD_INSTRUCTION:
 296         *unix_signal = SIGILL;
 297         *unix_code = code;
 298         break;
 299
 300     case EXC_ARITHMETIC:
 301         *unix_signal = SIGFPE;
 302         *unix_code = code;
 303         break;
 304
 305     default:
 306         return(FALSE);
 307     }
 308
 309     return(TRUE);
 310 }
 311
 312 #include <sys/systm.h>
 313 #include <sys/sysent.h>
 314
 315 int __pthread_cset(struct sysent *);
 316 void __pthread_creset(struct sysent *);
 317
 318 int
 319 __pthread_cset(struct sysent *callp)
 320 {
 321         unsigned int cancel_enable;
 322         thread_t thread;
 323         struct uthread * uthread;
 324
 325         thread = current_thread();
 326         uthread = get_bsdthread_info(thread);
 327
 328         cancel_enable = callp->sy_cancel;
 329         if (cancel_enable == _SYSCALL_CANCEL_NONE) {
 330                 uthread->uu_flag |= UT_NOTCANCELPT;
 331         } else {
 332                 if((uthread->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) {
 333                         if (cancel_enable == _SYSCALL_CANCEL_PRE)
 334                                 return(EINTR);
 335                         else
 336                                 thread_abort_safely(thread);
 337                 }
 338         }
 339         return(0);
 340 }
 341
 342
 343 void
 344 __pthread_creset(struct sysent *callp)
 345 {
 346
 347         unsigned int cancel_enable;
 348         thread_t thread;
 349         struct uthread * uthread;
 350
 351         thread = current_thread();
 352         uthread = get_bsdthread_info(thread);
 353
 354         cancel_enable = callp->sy_cancel;
 355         if (!cancel_enable)
 356                 uthread->uu_flag &= ~UT_NOTCANCELPT;
 357
 358 }
 359