bsd/kern/mach_process.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 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*-
  24  * Copyright (c) 1982, 1986, 1989, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  * (c) UNIX System Laboratories, Inc.
  27  * All or some portions of this file are derived from material licensed
  28  * to the University of California by American Telephone and Telegraph
  29  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  30  * the permission of UNIX System Laboratories, Inc.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
  61  */
  62 /*
  63  * HISTORY
  64  *
  65  *  10-Jun-97  Umesh Vaishampayan (umeshv@apple.com)
  66  *      Ported to PPC. Cleaned up the architecture specific code.
  67  */
  68
  69 #include <machine/reg.h>
  70 #include <machine/psl.h>
  71
  72 #include <sys/param.h>
  73 #include <sys/systm.h>
  74 #include <sys/proc.h>
  75 #include <sys/errno.h>
  76 #include <sys/ptrace.h>
  77 #include <sys/uio.h>
  78 #include <sys/user.h>
  79 #include <sys/sysctl.h>
  80
  81 #include <sys/mount.h>
  82
  83 #include <kern/task.h>
  84 #include <kern/thread.h>
  85 #include <mach/machine/thread_status.h>
  86
  87 /* Macros to clear/set/test flags. */
  88 #define SET(t, f)       (t) |= (f)
  89 #define CLR(t, f)       (t) &= ~(f)
  90 #define ISSET(t, f)     ((t) & (f))
  91
  92 void psignal_lock __P((struct proc *, int, int, int));
  93 /*
  94  * sys-trace system call.
  95  */
  96 struct ptrace_args {
  97         int     req;
  98         pid_t pid;
  99         caddr_t addr;
 100         int     data;
 101 };
 102 int
 103 ptrace(p, uap, retval)
 104         struct proc *p;
 105         struct ptrace_args *uap;
 106         register_t *retval;
 107 {
 108         struct proc *t = current_proc();        /* target process */
 109         vm_offset_t     start_addr, end_addr,
 110                         kern_addr, offset;
 111         vm_size_t       size;
 112         boolean_t       change_protection;
 113         task_t          task;
 114         thread_t        thread;
 115         thread_act_t    th_act;
 116         struct uthread  *ut;
 117         int             *locr0;
 118         int error = 0;
 119 #if defined(ppc)
 120         struct ppc_saved_state statep;
 121 #elif   defined(i386)
 122         struct i386_saved_state statep;
 123 #else
 124 #error architecture not supported
 125 #endif
 126         unsigned long state_count;
 127
 128
 129         /*
 130          *      Intercept and deal with "please trace me" request.
 131          */
 132         if (uap->req == PT_TRACE_ME) {
 133                 SET(p->p_flag, P_TRACED);
 134                 /* Non-attached case, our tracer is our parent. */
 135                 t->p_oppid = t->p_pptr->p_pid;
 136                 return(0);
 137         }
 138
 139         /*
 140          *      Locate victim, and make sure it is traceable.
 141          */
 142         if ((t = pfind(uap->pid)) == NULL)
 143                         return (ESRCH);
 144
 145
 146         /* We do not want ptrace to do anything with kernel, init
 147          * and mach_init
 148          */
 149         if (uap->pid <=2 )
 150                 return (EPERM);
 151
 152         task = t->task;
 153         if (uap->req == PT_ATTACH) {
 154
 155                 /*
 156                  * You can't attach to a process if:
 157                  *      (1) it's the process that's doing the attaching,
 158                  */
 159                 if (t->p_pid == p->p_pid)
 160                         return (EINVAL);
 161
 162                 /*
 163                  *      (2) it's already being traced, or
 164                  */
 165                 if (ISSET(t->p_flag, P_TRACED))
 166                         return (EBUSY);
 167
 168                 /*
 169                  *      (3) it's not owned by you, or is set-id on exec
 170                  *          (unless you're root).
 171                  */
 172                 if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
 173                         ISSET(t->p_flag, P_SUGID)) &&
 174                     (error = suser(p->p_ucred, &p->p_acflag)) != 0)
 175                         return (error);
 176
 177                 SET(t->p_flag, P_TRACED);
 178                 t->p_oppid = t->p_pptr->p_pid;
 179                 if (t->p_pptr != p)
 180                         proc_reparent(t, p);
 181
 182                 if (get_task_userstop(task) == 0 ) {
 183                         t->p_xstat = 0;
 184                         psignal(t, SIGSTOP);
 185                 } else {
 186                         t->p_xstat = SIGSTOP;
 187                         task_resume(task);
 188                 }
 189                 return(0);
 190         }
 191
 192         /*
 193          * You can't do what you want to the process if:
 194          *      (1) It's not being traced at all,
 195          */
 196         if (!ISSET(t->p_flag, P_TRACED))
 197                 return (EPERM);
 198
 199         /*
 200          *      (2) it's not being traced by _you_, or
 201          */
 202         if (t->p_pptr != p)
 203                 return (EBUSY);
 204
 205         /*
 206          *      (3) it's not currently stopped.
 207          */
 208         if (t->p_stat != SSTOP)
 209                 return (EBUSY);
 210
 211         /*
 212          *      Mach version of ptrace executes request directly here,
 213          *      thus simplifying the interaction of ptrace and signals.
 214          */
 215         switch (uap->req) {
 216
 217         case PT_DETACH:
 218                 if (t->p_oppid != t->p_pptr->p_pid) {
 219                         struct proc *pp;
 220
 221                         pp = pfind(t->p_oppid);
 222                         proc_reparent(t, pp ? pp : initproc);
 223                 }
 224
 225                 t->p_oppid = 0;
 226                 CLR(t->p_flag, P_TRACED);
 227                 goto resume;
 228
 229         case PT_KILL:
 230                 /*
 231                  *      Tell child process to kill itself after it
 232                  *      is resumed by adding NSIG to p_cursig. [see issig]
 233                  */
 234                 psignal_lock(t, SIGKILL, 0, 1);
 235                 goto resume;
 236
 237         case PT_STEP:                   /* single step the child */
 238         case PT_CONTINUE:               /* continue the child */
 239                 th_act = (thread_act_t)get_firstthread(task);
 240                 if (th_act == THREAD_NULL)
 241                         goto errorLabel;
 242                 ut = (uthread_t)get_bsdthread_info(th_act);
 243                 locr0 = ut->uu_ar0;
 244 #if defined(i386)
 245                 state_count = i386_NEW_THREAD_STATE_COUNT;
 246                 if (act_machine_get_state(th_act, i386_NEW_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 247                         goto errorLabel;
 248                 }
 249 #elif defined(ppc)
 250                 state_count = PPC_THREAD_STATE_COUNT;
 251                 if (act_machine_get_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 252                         goto errorLabel;
 253                 }
 254 #else
 255 #error architecture not supported
 256 #endif
 257                 if ((int)uap->addr != 1) {
 258 #if     defined(i386)
 259                         locr0[PC] = (int)uap->addr;
 260 #elif   defined(ppc)
 261 #define ALIGNED(addr,size)      (((unsigned)(addr)&((size)-1))==0)
 262                 if (!ALIGNED((int)uap->addr, sizeof(int)))
 263                         return (ERESTART);
 264
 265                 statep.srr0 = (int)uap->addr;
 266                 state_count = PPC_THREAD_STATE_COUNT;
 267                 if (act_machine_set_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 268                         goto errorLabel;
 269                 }
 270 #undef  ALIGNED
 271 #else
 272 #error architecture not implemented!
 273 #endif
 274                 } /* (int)uap->addr != 1 */
 275
 276                 if ((unsigned)uap->data < 0 || (unsigned)uap->data >= NSIG)
 277                         goto errorLabel;
 278
 279                 if (uap->data != 0) {
 280                         psignal_lock(t, uap->data, 0, 1);
 281                 }
 282 #if defined(ppc)
 283                 state_count = PPC_THREAD_STATE_COUNT;
 284                 if (act_machine_get_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 285                         goto errorLabel;
 286                 }
 287 #endif
 288
 289 #define MSR_SE_BIT      21
 290
 291                 if (uap->req == PT_STEP) {
 292 #if     defined(i386)
 293                         locr0[PS] |= PSL_T;
 294 #elif   defined(ppc)
 295                         statep.srr1 |= MASK(MSR_SE);
 296 #else
 297 #error architecture not implemented!
 298 #endif
 299                 } /* uap->req == PT_STEP */
 300                 else {  /* PT_CONTINUE - clear trace bit if set */
 301 #if defined(i386)
 302                         locr0[PS] &= ~PSL_T;
 303 #elif defined(ppc)
 304                         statep.srr1 &= ~MASK(MSR_SE);
 305 #endif
 306                 }
 307 #if defined (ppc)
 308                 state_count = PPC_THREAD_STATE_COUNT;
 309                 if (act_machine_set_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 310                         goto errorLabel;
 311                 }
 312 #endif
 313         resume:
 314                 t->p_xstat = uap->data;
 315                 t->p_stat = SRUN;
 316                 if (t->sigwait) {
 317                         wakeup((caddr_t)&(t->sigwait));
 318                         task_release(task);
 319                 }
 320                 break;
 321
 322         default:
 323         errorLabel:
 324                 return(EINVAL);
 325         }
 326         return(0);
 327 }
 328