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Annotation of kernel/machdep/i386/unix_signal.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /* 
        !            26:  * Copyright (c) 1992 NeXT, Inc.
        !            27:  *
        !            28:  * HISTORY
        !            29:  * 13 May 1992 ? at NeXT
        !            30:  *     Created.
        !            31:  */
        !            32: 
        !            33: #import <mach/mach_types.h>
        !            34: #import <mach/exception.h>
        !            35: 
        !            36: #import <sys/param.h>
        !            37: #import <sys/proc.h>
        !            38: #import <sys/user.h>
        !            39: 
        !            40: #import <i386/psl.h>
        !            41: 
        !            42: #import <machdep/i386/sel_inline.h>
        !            43: 
        !            44: #import <pc_support.h>
        !            45: #if    PC_SUPPORT
        !            46: #import <machdep/i386/pc_support/PCmiscInline.h>
        !            47: #endif
        !            48: 
        !            49: /*
        !            50:  * Send an interrupt to process.
        !            51:  *
        !            52:  * Stack is set up to allow sigcode stored
        !            53:  * in u. to call routine, followed by chmk
        !            54:  * to sigreturn routine below.  After sigreturn
        !            55:  * resets the signal mask, the stack, the frame 
        !            56:  * pointer, and the argument pointer, it returns
        !            57:  * to the user specified pc, psl.
        !            58:  */
        !            59: 
        !            60: void
        !            61: sendsig(p, catcher, sig, mask, code)
        !            62:        struct proc *p;
        !            63:        sig_t catcher;
        !            64:        int sig, mask;
        !            65:        u_long code;
        !            66: {
        !            67:     struct sigframe {
        !            68:        int                     sig;
        !            69:        int                     code;
        !            70:        struct sigcontext *     scp;
        !            71:     }                          frame, *fp;
        !            72:     struct sigcontext          context, *scp;
        !            73:        struct sigacts *ps = p->p_sigacts;
        !            74:     int                                oonstack;
        !            75:     thread_t                   thread = current_thread();
        !            76:     thread_saved_state_t *     saved_state = USER_REGS(thread);
        !            77:     
        !            78:        oonstack = ps->ps_sigstk.ss_flags & SA_ONSTACK;
        !            79:     if ((ps->ps_flags & SAS_ALTSTACK) && !oonstack &&
        !            80:                (ps->ps_sigonstack & sigmask(sig))) {
        !            81:                scp = (struct sigcontext *)(ps->ps_sigstk.ss_sp - 1);
        !            82:                        ps->ps_sigstk.ss_flags |= SA_ONSTACK;
        !            83:     } else
        !            84:            scp = (struct sigcontext *)saved_state->frame.esp - 1;
        !            85:     fp = (struct sigframe *)scp - 1;
        !            86: 
        !            87:     /* 
        !            88:      * Build the argument list for the signal handler.
        !            89:      */
        !            90:     frame.sig = sig;
        !            91:     if (sig == SIGILL || sig == SIGFPE) {
        !            92:            frame.code = code;
        !            93:     } else
        !            94:            frame.code = 0;
        !            95:     frame.scp = scp;
        !            96:     if (copyout((caddr_t)&frame, (caddr_t)fp, sizeof (frame)))
        !            97:        goto bad;
        !            98: #if    PC_SUPPORT
        !            99:     {
        !           100:        PCcontext_t     context = threadPCContext(thread);
        !           101:        
        !           102:        if (context && context->running) {
        !           103:            oonstack |= 02;
        !           104:            context->running = FALSE;
        !           105:        }
        !           106:     }
        !           107: #endif
        !           108:     /*
        !           109:      * Build the signal context to be used by sigreturn.
        !           110:      */
        !           111:     context.sc_onstack = oonstack;
        !           112:     context.sc_mask = mask;
        !           113:     context.sc_eax = saved_state->regs.eax;
        !           114:     context.sc_ebx = saved_state->regs.ebx;
        !           115:     context.sc_ecx = saved_state->regs.ecx;
        !           116:     context.sc_edx = saved_state->regs.edx;
        !           117:     context.sc_edi = saved_state->regs.edi;
        !           118:     context.sc_esi = saved_state->regs.esi;
        !           119:     context.sc_ebp = saved_state->regs.ebp;
        !           120:     context.sc_esp = saved_state->frame.esp;
        !           121:     context.sc_ss = sel_to_selector(saved_state->frame.ss);
        !           122:     context.sc_eflags = saved_state->frame.eflags;
        !           123:     context.sc_eip = saved_state->frame.eip;
        !           124:     context.sc_cs = sel_to_selector(saved_state->frame.cs);
        !           125:     if (saved_state->frame.eflags & EFL_VM) {
        !           126:        context.sc_ds = saved_state->frame.v_ds;
        !           127:        context.sc_es = saved_state->frame.v_es;
        !           128:        context.sc_fs = saved_state->frame.v_fs;
        !           129:        context.sc_gs = saved_state->frame.v_gs;
        !           130: 
        !           131:        saved_state->frame.eflags &= ~EFL_VM;
        !           132:     }
        !           133:     else {
        !           134:        context.sc_ds = sel_to_selector(saved_state->regs.ds);
        !           135:        context.sc_es = sel_to_selector(saved_state->regs.es);
        !           136:        context.sc_fs = sel_to_selector(saved_state->regs.fs);
        !           137:        context.sc_gs = sel_to_selector(saved_state->regs.gs);
        !           138:     }
        !           139:     if (copyout((caddr_t)&context, (caddr_t)scp, sizeof (context)))
        !           140:        goto bad;
        !           141:     saved_state->frame.eip = (unsigned int)catcher;
        !           142:     saved_state->frame.cs = UCODE_SEL;
        !           143: 
        !           144:     saved_state->frame.esp = (unsigned int)fp;
        !           145:     saved_state->frame.ss = UDATA_SEL;
        !           146: 
        !           147:     saved_state->regs.ds = UDATA_SEL;
        !           148:     saved_state->regs.es = UDATA_SEL;
        !           149:     saved_state->regs.fs = NULL_SEL;
        !           150:     saved_state->regs.gs = NULL_SEL;
        !           151:     return;
        !           152: 
        !           153: bad:
        !           154:        SIGACTION(p, SIGILL) = SIG_DFL;
        !           155:        sig = sigmask(SIGILL);
        !           156:        p->p_sigignore &= ~sig;
        !           157:        p->p_sigcatch &= ~sig;
        !           158:        p->p_sigmask &= ~sig;
        !           159:        psignal(p, SIGILL);
        !           160:        return;
        !           161: }
        !           162: 
        !           163: /*
        !           164:  * System call to cleanup state after a signal
        !           165:  * has been taken.  Reset signal mask and
        !           166:  * stack state from context left by sendsig (above).
        !           167:  * Return to previous pc and psl as specified by
        !           168:  * context left by sendsig. Check carefully to
        !           169:  * make sure that the user has not modified the
        !           170:  * psl to gain improper priviledges or to cause
        !           171:  * a machine fault.
        !           172:  */
        !           173: struct sigreturn_args {
        !           174:        struct sigcontext *sigcntxp;
        !           175: };
        !           176: /* ARGSUSED */
        !           177: int
        !           178: sigreturn(p, uap, retval)
        !           179:        struct proc *p;
        !           180:        struct sigreturn_args *uap;
        !           181:        int *retval;
        !           182: {
        !           183:     struct sigcontext          context;
        !           184:     thread_t                   thread = current_thread();
        !           185:        int error;
        !           186:     thread_saved_state_t *     saved_state = USER_REGS(thread);        
        !           187:     
        !           188:     if (error = copyin((caddr_t)uap->sigcntxp, (caddr_t)&context, 
        !           189:                                                sizeof (context)))
        !           190:                                        return(error);
        !           191:     if ((context.sc_eflags & EFL_VM) == 0 &&
        !           192:           (!valid_user_code_selector(context.sc_cs) ||
        !           193:            !valid_user_data_selector(context.sc_ds) ||
        !           194:            !valid_user_data_selector(context.sc_es) ||
        !           195:            !valid_user_data_selector(context.sc_fs) ||
        !           196:            !valid_user_data_selector(context.sc_gs) ||
        !           197:            !valid_user_stack_selector(context.sc_ss))
        !           198:        )
        !           199:        return(EINVAL);
        !           200: 
        !           201:     if (context.sc_onstack & 01)
        !           202:                        p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
        !           203:        else
        !           204:                p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
        !           205:        p->p_sigmask = context.sc_mask &~ sigcantmask;
        !           206:     saved_state->regs.eax = context.sc_eax;
        !           207:     saved_state->regs.ebx = context.sc_ebx;
        !           208:     saved_state->regs.ecx = context.sc_ecx;
        !           209:     saved_state->regs.edx = context.sc_edx;
        !           210:     saved_state->regs.edi = context.sc_edi;
        !           211:     saved_state->regs.esi = context.sc_esi;
        !           212:     saved_state->regs.ebp = context.sc_ebp;
        !           213:     saved_state->frame.esp = context.sc_esp;
        !           214:     saved_state->frame.ss = selector_to_sel(context.sc_ss);
        !           215:     saved_state->frame.eflags = context.sc_eflags;
        !           216:     saved_state->frame.eflags &= ~EFL_USERCLR;
        !           217:     saved_state->frame.eflags |= EFL_USERSET;
        !           218:     saved_state->frame.eip = context.sc_eip;
        !           219:     saved_state->frame.cs = selector_to_sel(context.sc_cs);
        !           220:     if (context.sc_eflags & EFL_VM) {
        !           221:        saved_state->regs.ds = NULL_SEL;
        !           222:        saved_state->regs.es = NULL_SEL;
        !           223:        saved_state->regs.fs = NULL_SEL;
        !           224:        saved_state->regs.gs = NULL_SEL;
        !           225:        saved_state->frame.v_ds = context.sc_ds;
        !           226:        saved_state->frame.v_es = context.sc_es;
        !           227:        saved_state->frame.v_fs = context.sc_fs;
        !           228:        saved_state->frame.v_gs = context.sc_gs;
        !           229: 
        !           230:        saved_state->frame.eflags |= EFL_VM;
        !           231:     }
        !           232:     else {
        !           233:        saved_state->regs.ds = selector_to_sel(context.sc_ds);
        !           234:        saved_state->regs.es = selector_to_sel(context.sc_es);
        !           235:        saved_state->regs.fs = selector_to_sel(context.sc_fs);
        !           236:        saved_state->regs.gs = selector_to_sel(context.sc_gs);
        !           237:     }
        !           238: #if    PC_SUPPORT
        !           239:     if (context.sc_onstack & 02) {
        !           240:        PCcontext_t     context = threadPCContext(thread);
        !           241:        
        !           242:        if (context)
        !           243:            context->running = TRUE;
        !           244:     }
        !           245: #endif
        !           246:        return (EJUSTRETURN);
        !           247: }
        !           248: 
        !           249: /*
        !           250:  * machine_exception() performs MD translation
        !           251:  * of a mach exception to a unix signal and code.
        !           252:  */
        !           253: 
        !           254: boolean_t
        !           255: machine_exception(
        !           256:     int                exception,
        !           257:     int                code,
        !           258:     int                subcode,
        !           259:     int                *unix_signal,
        !           260:     int                *unix_code
        !           261: )
        !           262: {
        !           263:     switch(exception) {
        !           264: 
        !           265:     case EXC_BAD_INSTRUCTION:
        !           266:        *unix_signal = SIGILL;
        !           267:        *unix_code = code;
        !           268:        break;
        !           269: 
        !           270:     case EXC_ARITHMETIC:
        !           271:        *unix_signal = SIGFPE;
        !           272:        *unix_code = code;
        !           273:        break;
        !           274: 
        !           275:     default:
        !           276:        return(FALSE);
        !           277:     }
        !           278:    
        !           279:     return(TRUE);
        !           280: }

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