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Annotation of XNU/bsd/dev/i386/unix_signal.c, revision 1.1

1.1     ! root        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:        psignal(p, SIGILL);
        !           181:        return;
        !           182: }
        !           183: 
        !           184: /*
        !           185:  * System call to cleanup state after a signal
        !           186:  * has been taken.  Reset signal mask and
        !           187:  * stack state from context left by sendsig (above).
        !           188:  * Return to previous pc and psl as specified by
        !           189:  * context left by sendsig. Check carefully to
        !           190:  * make sure that the user has not modified the
        !           191:  * psl to gain improper priviledges or to cause
        !           192:  * a machine fault.
        !           193:  */
        !           194: struct sigreturn_args {
        !           195:        struct sigcontext *sigcntxp;
        !           196: };
        !           197: /* ARGSUSED */
        !           198: int
        !           199: sigreturn(p, uap, retval)
        !           200:        struct proc *p;
        !           201:        struct sigreturn_args *uap;
        !           202:        int *retval;
        !           203: {
        !           204:     struct sigcontext          context;
        !           205:     thread_t                   thread = current_thread();
        !           206:     thread_act_t               th_act = current_act();
        !           207:        int error;
        !           208:     struct i386_saved_state*   saved_state = get_user_regs(th_act);    
        !           209:     
        !           210:     if (saved_state == NULL) 
        !           211:        return EINVAL;
        !           212: 
        !           213:     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context, 
        !           214:                                                sizeof (context))) 
        !           215:                                        return(error);
        !           216: 
        !           217: #if 0 /*FIXME*/
        !           218:     if ((context.sc_eflags & EFL_VM) == 0 &&
        !           219:           (!valid_user_code_selector(context.sc_cs) ||
        !           220:            !valid_user_data_selector(context.sc_ds) ||
        !           221:            !valid_user_data_selector(context.sc_es) ||
        !           222:            !valid_user_data_selector(context.sc_fs) ||
        !           223:            !valid_user_data_selector(context.sc_gs) ||
        !           224:            !valid_user_stack_selector(context.sc_ss))
        !           225:        )
        !           226:        return(EINVAL);
        !           227: #endif
        !           228: 
        !           229:     if (context.sc_onstack & 01)
        !           230:                        p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
        !           231:        else
        !           232:                p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
        !           233:        p->p_sigmask = context.sc_mask &~ sigcantmask;
        !           234:     saved_state->eax = context.sc_eax;
        !           235:     saved_state->ebx = context.sc_ebx;
        !           236:     saved_state->ecx = context.sc_ecx;
        !           237:     saved_state->edx = context.sc_edx;
        !           238:     saved_state->edi = context.sc_edi;
        !           239:     saved_state->esi = context.sc_esi;
        !           240:     saved_state->ebp = context.sc_ebp;
        !           241:     saved_state->uesp = context.sc_esp;
        !           242:     saved_state->ss = context.sc_ss;
        !           243:     saved_state->efl = context.sc_eflags;
        !           244:     saved_state->efl &= ~EFL_USERCLR;
        !           245:     saved_state->efl |= EFL_USERSET;
        !           246:     saved_state->eip = context.sc_eip;
        !           247:     saved_state->cs = context.sc_cs;
        !           248: 
        !           249:     if (context.sc_eflags & EFL_VM) {
        !           250:        saved_state->ds = NULL_SEG;
        !           251:        saved_state->es = NULL_SEG;
        !           252:        saved_state->fs = NULL_SEG;
        !           253:        saved_state->gs = NULL_SEG;
        !           254:        saved_state->v86_segs.v86_ds = context.sc_ds;
        !           255:        saved_state->v86_segs.v86_es = context.sc_es;
        !           256:        saved_state->v86_segs.v86_fs = context.sc_fs;
        !           257:        saved_state->v86_segs.v86_gs = context.sc_gs;
        !           258: 
        !           259:        saved_state->efl |= EFL_VM;
        !           260:     }
        !           261:     else {
        !           262:        saved_state->ds = context.sc_ds;
        !           263:        saved_state->es = context.sc_es;
        !           264:        saved_state->fs = context.sc_fs;
        !           265:        saved_state->gs = context.sc_gs;
        !           266:     }
        !           267: 
        !           268: #if    PC_SUPPORT
        !           269:     if (context.sc_onstack & 02) {
        !           270:        PCcontext_t     context = threadPCContext(thread);
        !           271:        
        !           272:        if (context)
        !           273:            context->running = TRUE;
        !           274:     }
        !           275: #endif
        !           276: 
        !           277:        return (EJUSTRETURN);
        !           278: }
        !           279: 
        !           280: /*
        !           281:  * machine_exception() performs MD translation
        !           282:  * of a mach exception to a unix signal and code.
        !           283:  */
        !           284: 
        !           285: boolean_t
        !           286: machine_exception(
        !           287:     int                exception,
        !           288:     int                code,
        !           289:     int                subcode,
        !           290:     int                *unix_signal,
        !           291:     int                *unix_code
        !           292: )
        !           293: {
        !           294: 
        !           295:     switch(exception) {
        !           296: 
        !           297:     case EXC_BAD_INSTRUCTION:
        !           298:        *unix_signal = SIGILL;
        !           299:        *unix_code = code;
        !           300:        break;
        !           301: 
        !           302:     case EXC_ARITHMETIC:
        !           303:        *unix_signal = SIGFPE;
        !           304:        *unix_code = code;
        !           305:        break;
        !           306: 
        !           307:     default:
        !           308:        return(FALSE);
        !           309:     }
        !           310:    
        !           311:     return(TRUE);
        !           312: }

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