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 #include <sys/wait.h>
  81
  82 #include <sys/mount.h>
  83
  84 #include <kern/task.h>
  85 #include <kern/thread.h>
  86 #include <mach/machine/thread_status.h>
  87
  88 /* Macros to clear/set/test flags. */
  89 #define SET(t, f)       (t) |= (f)
  90 #define CLR(t, f)       (t) &= ~(f)
  91 #define ISSET(t, f)     ((t) & (f))
  92
  93 void psignal_lock __P((struct proc *, int, int, int));
  94 /*
  95  * sys-trace system call.
  96  */
  97 struct ptrace_args {
  98         int     req;
  99         pid_t pid;
 100         caddr_t addr;
 101         int     data;
 102 };
 103 int
 104 ptrace(p, uap, retval)
 105         struct proc *p;
 106         struct ptrace_args *uap;
 107         register_t *retval;
 108 {
 109         struct proc *t = current_proc();        /* target process */
 110         vm_offset_t     start_addr, end_addr,
 111                         kern_addr, offset;
 112         vm_size_t       size;
 113         boolean_t       change_protection;
 114         task_t          task;
 115         thread_t        thread;
 116         thread_act_t    th_act;
 117         struct uthread  *ut;
 118         int             *locr0;
 119         int error = 0;
 120 #if defined(ppc)
 121         struct ppc_saved_state statep;
 122 #elif   defined(i386)
 123         struct i386_saved_state statep;
 124 #else
 125 #error architecture not supported
 126 #endif
 127         unsigned long state_count;
 128
 129
 130         if (uap->req == PT_DENY_ATTACH) {
 131                 if (ISSET(p->p_flag, P_TRACED)) {
 132                                 exit1(p, W_EXITCODE(ENOTSUP, 0), retval);
 133                                 /* drop funnel befewo we return */
 134                                 thread_funnel_set(kernel_flock, FALSE);
 135                                 thread_exception_return();
 136                                 /* NOTREACHED */
 137                         }
 138                 SET(p->p_flag, P_NOATTACH);
 139
 140                 return(0);
 141         }
 142
 143         /*
 144          *      Intercept and deal with "please trace me" request.
 145          */
 146         if (uap->req == PT_TRACE_ME) {
 147                 SET(p->p_flag, P_TRACED);
 148                 /* Non-attached case, our tracer is our parent. */
 149                 t->p_oppid = t->p_pptr->p_pid;
 150                 return(0);
 151         }
 152
 153         /*
 154          *      Locate victim, and make sure it is traceable.
 155          */
 156         if ((t = pfind(uap->pid)) == NULL)
 157                         return (ESRCH);
 158
 159
 160         /* We do not want ptrace to do anything with kernel, init
 161          * and mach_init
 162          */
 163         if (uap->pid <=2 )
 164                 return (EPERM);
 165
 166         task = t->task;
 167         if (uap->req == PT_ATTACH) {
 168
 169                 /*
 170                  * You can't attach to a process if:
 171                  *      (1) it's the process that's doing the attaching,
 172                  */
 173                 if (t->p_pid == p->p_pid)
 174                         return (EINVAL);
 175
 176                 /*
 177                  *      (2) it's already being traced, or
 178                  */
 179                 if (ISSET(t->p_flag, P_TRACED))
 180                         return (EBUSY);
 181
 182                 /*
 183                  *      (3) it's not owned by you, or is set-id on exec
 184                  *          (unless you're root).
 185                  */
 186                 if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
 187                         ISSET(t->p_flag, P_SUGID)) &&
 188                     (error = suser(p->p_ucred, &p->p_acflag)) != 0)
 189                         return (error);
 190
 191                 if (ISSET(t->p_flag, P_NOATTACH)) {
 192                         psignal(p, SIGSEGV);
 193                         return (EBUSY);
 194                 }
 195                 SET(t->p_flag, P_TRACED);
 196                 t->p_oppid = t->p_pptr->p_pid;
 197                 if (t->p_pptr != p)
 198                         proc_reparent(t, p);
 199
 200                 if (get_task_userstop(task) == 0 ) {
 201                         t->p_xstat = 0;
 202                         psignal(t, SIGSTOP);
 203                 } else {
 204                         t->p_xstat = SIGSTOP;
 205                         task_resume(task);
 206                 }
 207                 return(0);
 208         }
 209
 210         /*
 211          * You can't do what you want to the process if:
 212          *      (1) It's not being traced at all,
 213          */
 214         if (!ISSET(t->p_flag, P_TRACED))
 215                 return (EPERM);
 216
 217         /*
 218          *      (2) it's not being traced by _you_, or
 219          */
 220         if (t->p_pptr != p)
 221                 return (EBUSY);
 222
 223         /*
 224          *      (3) it's not currently stopped.
 225          */
 226         if (t->p_stat != SSTOP)
 227                 return (EBUSY);
 228
 229         /*
 230          *      Mach version of ptrace executes request directly here,
 231          *      thus simplifying the interaction of ptrace and signals.
 232          */
 233         switch (uap->req) {
 234
 235         case PT_DETACH:
 236                 if (t->p_oppid != t->p_pptr->p_pid) {
 237                         struct proc *pp;
 238
 239                         pp = pfind(t->p_oppid);
 240                         proc_reparent(t, pp ? pp : initproc);
 241                 }
 242
 243                 t->p_oppid = 0;
 244                 CLR(t->p_flag, P_TRACED);
 245                 goto resume;
 246
 247         case PT_KILL:
 248                 /*
 249                  *      Tell child process to kill itself after it
 250                  *      is resumed by adding NSIG to p_cursig. [see issig]
 251                  */
 252                 psignal_lock(t, SIGKILL, 0, 0);
 253                 goto resume;
 254
 255         case PT_STEP:                   /* single step the child */
 256         case PT_CONTINUE:               /* continue the child */
 257                 th_act = (thread_act_t)get_firstthread(task);
 258                 if (th_act == THREAD_NULL)
 259                         goto errorLabel;
 260                 ut = (uthread_t)get_bsdthread_info(th_act);
 261                 locr0 = ut->uu_ar0;
 262 #if defined(i386)
 263                 state_count = i386_NEW_THREAD_STATE_COUNT;
 264                 if (act_machine_get_state(th_act, i386_NEW_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 265                         goto errorLabel;
 266                 }
 267 #elif defined(ppc)
 268                 state_count = PPC_THREAD_STATE_COUNT;
 269                 if (act_machine_get_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 270                         goto errorLabel;
 271                 }
 272 #else
 273 #error architecture not supported
 274 #endif
 275                 if ((int)uap->addr != 1) {
 276 #if     defined(i386)
 277                         locr0[PC] = (int)uap->addr;
 278 #elif   defined(ppc)
 279 #define ALIGNED(addr,size)      (((unsigned)(addr)&((size)-1))==0)
 280                 if (!ALIGNED((int)uap->addr, sizeof(int)))
 281                         return (ERESTART);
 282
 283                 statep.srr0 = (int)uap->addr;
 284                 state_count = PPC_THREAD_STATE_COUNT;
 285                 if (act_machine_set_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 286                         goto errorLabel;
 287                 }
 288 #undef  ALIGNED
 289 #else
 290 #error architecture not implemented!
 291 #endif
 292                 } /* (int)uap->addr != 1 */
 293
 294                 if ((unsigned)uap->data < 0 || (unsigned)uap->data >= NSIG)
 295                         goto errorLabel;
 296
 297                 if (uap->data != 0) {
 298                         psignal_lock(t, uap->data, 0, 1);
 299                 }
 300 #if defined(ppc)
 301                 state_count = PPC_THREAD_STATE_COUNT;
 302                 if (act_machine_get_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 303                         goto errorLabel;
 304                 }
 305 #endif
 306
 307 #define MSR_SE_BIT      21
 308
 309                 if (uap->req == PT_STEP) {
 310 #if     defined(i386)
 311                         locr0[PS] |= PSL_T;
 312 #elif   defined(ppc)
 313                         statep.srr1 |= MASK(MSR_SE);
 314 #else
 315 #error architecture not implemented!
 316 #endif
 317                 } /* uap->req == PT_STEP */
 318                 else {  /* PT_CONTINUE - clear trace bit if set */
 319 #if defined(i386)
 320                         locr0[PS] &= ~PSL_T;
 321 #elif defined(ppc)
 322                         statep.srr1 &= ~MASK(MSR_SE);
 323 #endif
 324                 }
 325 #if defined (ppc)
 326                 state_count = PPC_THREAD_STATE_COUNT;
 327                 if (act_machine_set_state(th_act, PPC_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 328                         goto errorLabel;
 329                 }
 330 #endif
 331         resume:
 332                 t->p_xstat = uap->data;
 333                 t->p_stat = SRUN;
 334                 if (t->sigwait) {
 335                         wakeup((caddr_t)&(t->sigwait));
 336                         task_release(task);
 337                 }
 338                 break;
 339
 340         default:
 341         errorLabel:
 342                 return(EINVAL);
 343         }
 344         return(0);
 345 }
 346