bsd/kern/mach_process.c

   1 /*
   2  * Copyright (c) 2000-2004 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 #include <machine/reg.h>
  64 #include <machine/psl.h>
  65
  66 #include <sys/param.h>
  67 #include <sys/systm.h>
  68 #include <sys/proc.h>
  69 #include <sys/errno.h>
  70 #include <sys/ptrace.h>
  71 #include <sys/uio.h>
  72 #include <sys/user.h>
  73 #include <sys/sysctl.h>
  74 #include <sys/wait.h>
  75
  76 #include <sys/mount.h>
  77
  78 #include <bsm/audit_kernel.h>
  79
  80 #include <kern/task.h>
  81 #include <kern/thread.h>
  82 #include <mach/machine/thread_status.h>
  83
  84 /* Macros to clear/set/test flags. */
  85 #define SET(t, f)       (t) |= (f)
  86 #define CLR(t, f)       (t) &= ~(f)
  87 #define ISSET(t, f)     ((t) & (f))
  88
  89 void psignal_lock __P((struct proc *, int, int));
  90
  91 /*
  92  * sys-trace system call.
  93  */
  94 struct ptrace_args {
  95         int     req;
  96         pid_t pid;
  97         caddr_t addr;
  98         int     data;
  99 };
 100
 101 int
 102 ptrace(p, uap, retval)
 103         struct proc *p;
 104         struct ptrace_args *uap;
 105         register_t *retval;
 106 {
 107         struct proc *t = current_proc();        /* target process */
 108         vm_offset_t     start_addr, end_addr,
 109                         kern_addr, offset;
 110         vm_size_t       size;
 111         task_t          task;
 112         thread_t        thread;
 113         thread_act_t    th_act;
 114         struct uthread  *ut;
 115         int             *locr0;
 116         int error = 0;
 117 #if defined(ppc)
 118         struct ppc_thread_state64 statep;
 119 #elif   defined(i386)
 120         struct i386_saved_state statep;
 121 #else
 122 #error architecture not supported
 123 #endif
 124         unsigned long state_count;
 125         int tr_sigexc = 0;
 126
 127         AUDIT_ARG(cmd, uap->req);
 128         AUDIT_ARG(pid, uap->pid);
 129         AUDIT_ARG(addr, uap->addr);
 130         AUDIT_ARG(value, uap->data);
 131
 132         if (uap->req == PT_DENY_ATTACH) {
 133                 if (ISSET(p->p_flag, P_TRACED)) {
 134                                 exit1(p, W_EXITCODE(ENOTSUP, 0), retval);
 135                                 /* drop funnel before we return */
 136                                 thread_funnel_set(kernel_flock, FALSE);
 137                                 thread_exception_return();
 138                                 /* NOTREACHED */
 139                         }
 140                 SET(p->p_flag, P_NOATTACH);
 141
 142                 return(0);
 143         }
 144
 145         if (uap->req == PT_FORCEQUOTA) {
 146                 if (is_suser()) {
 147                         SET(t->p_flag, P_FORCEQUOTA);
 148                         return (0);
 149                 } else
 150                         return (EPERM);
 151         }
 152
 153         /*
 154          *      Intercept and deal with "please trace me" request.
 155          */
 156         if (uap->req == PT_TRACE_ME) {
 157                 SET(p->p_flag, P_TRACED);
 158                 /* Non-attached case, our tracer is our parent. */
 159                 t->p_oppid = t->p_pptr->p_pid;
 160                 return(0);
 161         }
 162         if (uap->req == PT_SIGEXC) {
 163                 if (ISSET(p->p_flag, P_TRACED)) {
 164                         SET(p->p_flag, P_SIGEXC);
 165                         return(0);
 166                 } else
 167                         return(EINVAL);
 168         }
 169
 170         /*
 171          *      Locate victim, and make sure it is traceable.
 172          */
 173         if ((t = pfind(uap->pid)) == NULL)
 174                         return (ESRCH);
 175
 176
 177         AUDIT_ARG(process, t);
 178
 179         /* We do not want ptrace to do anything with kernel, init
 180          * and mach_init
 181          */
 182         if (uap->pid <=2 )
 183                 return (EPERM);
 184
 185         task = t->task;
 186         if (uap->req == PT_ATTACHEXC) {
 187                 uap->req = PT_ATTACH;
 188                 tr_sigexc = 1;
 189         }
 190         if (uap->req == PT_ATTACH) {
 191
 192                 /*
 193                  * You can't attach to a process if:
 194                  *      (1) it's the process that's doing the attaching,
 195                  */
 196                 if (t->p_pid == p->p_pid)
 197                         return (EINVAL);
 198
 199                 /*
 200                  *      (2) it's already being traced, or
 201                  */
 202                 if (ISSET(t->p_flag, P_TRACED))
 203                         return (EBUSY);
 204
 205                 /*
 206                  *      (3) it's not owned by you, or is set-id on exec
 207                  *          (unless you're root).
 208                  */
 209                 if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
 210                         ISSET(t->p_flag, P_SUGID)) &&
 211                     (error = suser(p->p_ucred, &p->p_acflag)) != 0)
 212                         return (error);
 213
 214                 if ((p->p_flag & P_TRACED) && isinferior(p, t))
 215                         return(EPERM);
 216
 217                 if (ISSET(t->p_flag, P_NOATTACH)) {
 218                         psignal(p, SIGSEGV);
 219                         return (EBUSY);
 220                 }
 221                 SET(t->p_flag, P_TRACED);
 222                 if (tr_sigexc)
 223                         SET(t->p_flag, P_SIGEXC);
 224
 225                 t->p_oppid = t->p_pptr->p_pid;
 226                 if (t->p_pptr != p)
 227                         proc_reparent(t, p);
 228
 229                 if (get_task_userstop(task) == 0 ) {
 230                         t->p_xstat = 0;
 231                         psignal(t, SIGSTOP);
 232                 } else {
 233                         t->p_xstat = SIGSTOP;
 234                         task_resume(task);
 235                 }
 236                 return(0);
 237         }
 238
 239         /*
 240          * You can't do what you want to the process if:
 241          *      (1) It's not being traced at all,
 242          */
 243         if (!ISSET(t->p_flag, P_TRACED))
 244                 return (EPERM);
 245
 246         /*
 247          *      (2) it's not being traced by _you_, or
 248          */
 249         if (t->p_pptr != p)
 250                 return (EBUSY);
 251
 252         /*
 253          *      (3) it's not currently stopped.
 254          */
 255         if (t->p_stat != SSTOP)
 256                 return (EBUSY);
 257
 258         /*
 259          *      Mach version of ptrace executes request directly here,
 260          *      thus simplifying the interaction of ptrace and signals.
 261          */
 262         switch (uap->req) {
 263
 264         case PT_DETACH:
 265                 if (t->p_oppid != t->p_pptr->p_pid) {
 266                         struct proc *pp;
 267
 268                         pp = pfind(t->p_oppid);
 269                         proc_reparent(t, pp ? pp : initproc);
 270                 }
 271
 272                 t->p_oppid = 0;
 273                 CLR(t->p_flag, P_TRACED);
 274                 CLR(t->p_flag, P_SIGEXC);
 275                 goto resume;
 276
 277         case PT_KILL:
 278                 /*
 279                  *      Tell child process to kill itself after it
 280                  *      is resumed by adding NSIG to p_cursig. [see issig]
 281                  */
 282                 psignal_lock(t, SIGKILL, 0);
 283                 goto resume;
 284
 285         case PT_STEP:                   /* single step the child */
 286         case PT_CONTINUE:               /* continue the child */
 287                 th_act = (thread_act_t)get_firstthread(task);
 288                 if (th_act == THR_ACT_NULL)
 289                         goto errorLabel;
 290                 ut = (uthread_t)get_bsdthread_info(th_act);
 291                 locr0 = ut->uu_ar0;
 292 #if defined(i386)
 293                 state_count = i386_NEW_THREAD_STATE_COUNT;
 294                 if (thread_getstatus(th_act, i386_NEW_THREAD_STATE, &statep, &state_count)  != KERN_SUCCESS) {
 295                         goto errorLabel;
 296                 }
 297 #elif defined(ppc)
 298                 state_count = PPC_THREAD_STATE64_COUNT;
 299                 if (thread_getstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 300                         goto errorLabel;
 301                 }
 302 #else
 303 #error architecture not supported
 304 #endif
 305                 if ((int)uap->addr != 1) {
 306 #if     defined(i386)
 307                         locr0[PC] = (int)uap->addr;
 308 #elif   defined(ppc)
 309 #define ALIGNED(addr,size)      (((unsigned)(addr)&((size)-1))==0)
 310                 if (!ALIGNED((int)uap->addr, sizeof(int)))
 311                         return (ERESTART);
 312
 313                 statep.srr0 = (uint64_t)((uint32_t)uap->addr);
 314                 state_count = PPC_THREAD_STATE64_COUNT;
 315                 if (thread_setstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 316                         goto errorLabel;
 317                 }
 318 #undef  ALIGNED
 319 #else
 320 #error architecture not implemented!
 321 #endif
 322                 } /* (int)uap->addr != 1 */
 323
 324                 if ((unsigned)uap->data < 0 || (unsigned)uap->data >= NSIG)
 325                         goto errorLabel;
 326
 327                 if (uap->data != 0) {
 328                         psignal_lock(t, uap->data, 0);
 329                 }
 330 #if defined(ppc)
 331                 state_count = PPC_THREAD_STATE64_COUNT;
 332                 if (thread_getstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 333                         goto errorLabel;
 334                 }
 335 #endif
 336
 337 #define MSR_SE_BIT      21
 338
 339                 if (uap->req == PT_STEP) {
 340 #if     defined(i386)
 341                         locr0[PS] |= PSL_T;
 342 #elif   defined(ppc)
 343                         statep.srr1 |= MASK(MSR_SE);
 344 #else
 345 #error architecture not implemented!
 346 #endif
 347                 } /* uap->req == PT_STEP */
 348                 else {  /* PT_CONTINUE - clear trace bit if set */
 349 #if defined(i386)
 350                         locr0[PS] &= ~PSL_T;
 351 #elif defined(ppc)
 352                         statep.srr1 &= ~MASK(MSR_SE);
 353 #endif
 354                 }
 355 #if defined (ppc)
 356                 state_count = PPC_THREAD_STATE64_COUNT;
 357                 if (thread_setstatus(th_act, PPC_THREAD_STATE64, &statep, &state_count)  != KERN_SUCCESS) {
 358                         goto errorLabel;
 359                 }
 360 #endif
 361         resume:
 362                 t->p_xstat = uap->data;
 363                 t->p_stat = SRUN;
 364                 if (t->sigwait) {
 365                         wakeup((caddr_t)&(t->sigwait));
 366                         if ((t->p_flag & P_SIGEXC) == 0)
 367                                 task_release(task);
 368                 }
 369                 break;
 370
 371         case PT_THUPDATE:  {
 372                 thread_act_t target_act;
 373
 374                 if ((unsigned)uap->data >= NSIG)
 375                         goto errorLabel;
 376                 th_act = (thread_act_t)port_name_to_act((void *)uap->addr);
 377                 if (th_act == THR_ACT_NULL)
 378                         return (ESRCH);
 379                 ut = (uthread_t)get_bsdthread_info(th_act);
 380                 if (uap->data)
 381                         ut->uu_siglist |= sigmask(uap->data);
 382                 t->p_xstat = uap->data;
 383                 t->p_stat = SRUN;
 384                 act_deallocate(th_act);
 385                 return(0);
 386                 }
 387                 break;
 388 errorLabel:
 389         default:
 390                 return(EINVAL);
 391         }
 392
 393         return(0);
 394 }
 395