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