bsd/kern/mach_process.c

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  26 /*-
  27  * Copyright (c) 1982, 1986, 1989, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  * (c) UNIX System Laboratories, Inc.
  30  * All or some portions of this file are derived from material licensed
  31  * to the University of California by American Telephone and Telegraph
  32  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  33  * the permission of UNIX System Laboratories, Inc.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  *      from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
  64  */
  65
  66 #include <machine/reg.h>
  67 #include <machine/psl.h>
  68
  69 #include <sys/param.h>
  70 #include <sys/systm.h>
  71 #include <sys/proc.h>
  72 #include <sys/errno.h>
  73 #include <sys/ptrace.h>
  74 #include <sys/uio.h>
  75 #include <sys/user.h>
  76 #include <sys/sysctl.h>
  77 #include <sys/wait.h>
  78
  79 #include <sys/mount.h>
  80
  81 #include <kern/task.h>
  82 #include <kern/thread.h>
  83 #include <mach/machine/thread_status.h>
  84
  85 /* Macros to clear/set/test flags. */
  86 #define SET(t, f)       (t) |= (f)
  87 #define CLR(t, f)       (t) &= ~(f)
  88 #define ISSET(t, f)     ((t) & (f))
  89
  90 void psignal_lock __P((struct proc *, int, int));
  91 int isinferior __P((struct proc *, struct proc *));
  92
  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
 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         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_thread_state64 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         int tr_sigexc = 0;
 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 before 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         if (uap->req == PT_FORCEQUOTA) {
 144                 if (is_suser()) {
 145                         SET(t->p_flag, P_FORCEQUOTA);
 146                         return (0);
 147                 } else
 148                         return (EPERM);
 149         }
 150
 151         /*
 152          *      Intercept and deal with "please trace me" request.
 153          */
 154         if (uap->req == PT_TRACE_ME) {
 155                 SET(p->p_flag, P_TRACED);
 156                 /* Non-attached case, our tracer is our parent. */
 157                 t->p_oppid = t->p_pptr->p_pid;
 158                 return(0);
 159         }
 160         if (uap->req == PT_SIGEXC) {
 161                 if (ISSET(p->p_flag, P_TRACED)) {
 162                         SET(p->p_flag, P_SIGEXC);
 163                         return(0);
 164                 } else
 165                         return(EINVAL);
 166         }
 167
 168         /*
 169          *      Locate victim, and make sure it is traceable.
 170          */
 171         if ((t = pfind(uap->pid)) == NULL)
 172                         return (ESRCH);
 173
 174
 175         /* We do not want ptrace to do anything with kernel, init
 176          * and mach_init
 177          */
 178         if (uap->pid <=2 )
 179                 return (EPERM);
 180
 181         task = t->task;
 182         if (uap->req == PT_ATTACHEXC) {
 183                 uap->req = PT_ATTACH;
 184                 tr_sigexc = 1;
 185         }
 186         if (uap->req == PT_ATTACH) {
 187
 188                 /*
 189                  * You can't attach to a process if:
 190                  *      (1) it's the process that's doing the attaching,
 191                  */
 192                 if (t->p_pid == p->p_pid)
 193                         return (EINVAL);
 194
 195                 /*
 196                  *      (2) it's already being traced, or
 197                  */
 198                 if (ISSET(t->p_flag, P_TRACED))
 199                         return (EBUSY);
 200
 201                 /*
 202                  *      (3) it's not owned by you, or is set-id on exec
 203                  *          (unless you're root).
 204                  */
 205                 if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
 206                         ISSET(t->p_flag, P_SUGID)) &&
 207                     (error = suser(p->p_ucred, &p->p_acflag)) != 0)
 208                         return (error);
 209
 210                 if ((p->p_flag & P_TRACED) && isinferior(p, t))
 211                         return(EPERM);
 212
 213                 if (ISSET(t->p_flag, P_NOATTACH)) {
 214                         psignal(p, SIGSEGV);
 215                         return (EBUSY);
 216                 }
 217                 SET(t->p_flag, P_TRACED);
 218                 if (tr_sigexc)
 219                         SET(t->p_flag, P_SIGEXC);
 220
 221                 t->p_oppid = t->p_pptr->p_pid;
 222                 if (t->p_pptr != p)
 223                         proc_reparent(t, p);
 224
 225                 if (get_task_userstop(task) == 0 ) {
 226                         t->p_xstat = 0;
 227                         psignal(t, SIGSTOP);
 228                 } else {
 229                         t->p_xstat = SIGSTOP;
 230                         task_resume(task);
 231                 }
 232                 return(0);
 233         }
 234
 235         /*
 236          * You can't do what you want to the process if:
 237          *      (1) It's not being traced at all,
 238          */
 239         if (!ISSET(t->p_flag, P_TRACED))
 240                 return (EPERM);
 241
 242         /*
 243          *      (2) it's not being traced by _you_, or
 244          */
 245         if (t->p_pptr != p)
 246                 return (EBUSY);
 247
 248         /*
 249          *      (3) it's not currently stopped.
 250          */
 251         if (t->p_stat != SSTOP)
 252                 return (EBUSY);
 253
 254         /*
 255          *      Mach version of ptrace executes request directly here,
 256          *      thus simplifying the interaction of ptrace and signals.
 257          */
 258         switch (uap->req) {
 259
 260         case PT_DETACH:
 261                 if (t->p_oppid != t->p_pptr->p_pid) {
 262                         struct proc *pp;
 263
 264                         pp = pfind(t->p_oppid);
 265                         proc_reparent(t, pp ? pp : initproc);
 266                 }
 267
 268                 t->p_oppid = 0;
 269                 CLR(t->p_flag, P_TRACED);
 270                 CLR(t->p_flag, P_SIGEXC);
 271                 goto resume;
 272
 273         case PT_KILL:
 274                 /*
 275                  *      Tell child process to kill itself after it
 276                  *      is resumed by adding NSIG to p_cursig. [see issig]
 277                  */
 278                 psignal_lock(t, SIGKILL, 0);
 279                 goto resume;
 280
 281         case PT_STEP:                   /* single step the child */
 282         case PT_CONTINUE:               /* continue the child */
 283                 th_act = (thread_act_t)get_firstthread(task);
 284                 if (th_act == THR_ACT_NULL)
 285                         goto errorLabel;
 286                 ut = (uthread_t)get_bsdthread_info(th_act);
 287                 locr0 = ut->uu_ar0;
 288 #if defined(i386)
 289                 state_count = i386_NEW_THREAD_STATE_COUNT;
 290                 if (thread_getstatus(th_act, i386_NEW_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 291                         goto errorLabel;
 292                 }
 293 #elif defined(ppc)
 294                 state_count = PPC_THREAD_STATE64_COUNT;
 295                 if (thread_getstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 296                         goto errorLabel;
 297                 }
 298 #else
 299 #error architecture not supported
 300 #endif
 301                 if ((int)uap->addr != 1) {
 302 #if     defined(i386)
 303                         locr0[PC] = (int)uap->addr;
 304 #elif   defined(ppc)
 305 #define ALIGNED(addr,size)      (((unsigned)(addr)&((size)-1))==0)
 306                 if (!ALIGNED((int)uap->addr, sizeof(int)))
 307                         return (ERESTART);
 308
 309                 statep.srr0 = (uint64_t)((uint32_t)uap->addr);
 310                 state_count = PPC_THREAD_STATE64_COUNT;
 311                 if (thread_setstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 312                         goto errorLabel;
 313                 }
 314 #undef  ALIGNED
 315 #else
 316 #error architecture not implemented!
 317 #endif
 318                 } /* (int)uap->addr != 1 */
 319
 320                 if ((unsigned)uap->data < 0 || (unsigned)uap->data >= NSIG)
 321                         goto errorLabel;
 322
 323                 if (uap->data != 0) {
 324                         psignal_lock(t, uap->data, 0);
 325                 }
 326 #if defined(ppc)
 327                 state_count = PPC_THREAD_STATE64_COUNT;
 328                 if (thread_getstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 329                         goto errorLabel;
 330                 }
 331 #endif
 332
 333 #define MSR_SE_BIT      21
 334
 335                 if (uap->req == PT_STEP) {
 336 #if     defined(i386)
 337                         locr0[PS] |= PSL_T;
 338 #elif   defined(ppc)
 339                         statep.srr1 |= MASK(MSR_SE);
 340 #else
 341 #error architecture not implemented!
 342 #endif
 343                 } /* uap->req == PT_STEP */
 344                 else {  /* PT_CONTINUE - clear trace bit if set */
 345 #if defined(i386)
 346                         locr0[PS] &= ~PSL_T;
 347 #elif defined(ppc)
 348                         statep.srr1 &= ~MASK(MSR_SE);
 349 #endif
 350                 }
 351 #if defined (ppc)
 352                 state_count = PPC_THREAD_STATE64_COUNT;
 353                 if (thread_setstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 354                         goto errorLabel;
 355                 }
 356 #endif
 357         resume:
 358                 t->p_xstat = uap->data;
 359                 t->p_stat = SRUN;
 360                 if (t->sigwait) {
 361                         wakeup((caddr_t)&(t->sigwait));
 362                         if ((t->p_flag & P_SIGEXC) == 0)
 363                                 task_release(task);
 364                 }
 365                 break;
 366
 367         case PT_THUPDATE:  {
 368                 thread_act_t target_act;
 369
 370                 if ((unsigned)uap->data >= NSIG)
 371                         goto errorLabel;
 372                 th_act = (thread_act_t)port_name_to_act((void *)uap->addr);
 373                 if (th_act == THR_ACT_NULL)
 374                         return (ESRCH);
 375                 ut = (uthread_t)get_bsdthread_info(th_act);
 376                 if (uap->data)
 377                         ut->uu_siglist |= sigmask(uap->data);
 378                 t->p_xstat = uap->data;
 379                 t->p_stat = SRUN;
 380                 act_deallocate(th_act);
 381                 return(0);
 382                 }
 383                 break;
 384 errorLabel:
 385         default:
 386                 return(EINVAL);
 387         }
 388
 389         return(0);
 390 }
 391