sys/kern/sys_process.c

   1 /*-
   2  * Copyright (c) 1994, Sean Eric Fagan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Sean Eric Fagan.
  16  * 4. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include "opt_compat.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/lock.h>
  40 #include <sys/mutex.h>
  41 #include <sys/syscallsubr.h>
  42 #include <sys/sysent.h>
  43 #include <sys/sysproto.h>
  44 #include <sys/pioctl.h>
  45 #include <sys/priv.h>
  46 #include <sys/proc.h>
  47 #include <sys/vnode.h>
  48 #include <sys/ptrace.h>
  49 #include <sys/rwlock.h>
  50 #include <sys/sx.h>
  51 #include <sys/malloc.h>
  52 #include <sys/signalvar.h>
  53
  54 #include <machine/reg.h>
  55
  56 #include <security/audit/audit.h>
  57
  58 #include <vm/vm.h>
  59 #include <vm/pmap.h>
  60 #include <vm/vm_extern.h>
  61 #include <vm/vm_map.h>
  62 #include <vm/vm_kern.h>
  63 #include <vm/vm_object.h>
  64 #include <vm/vm_page.h>
  65 #include <vm/vm_param.h>
  66
  67 #ifdef COMPAT_FREEBSD32
  68 #include <sys/procfs.h>
  69 #include <compat/freebsd32/freebsd32_signal.h>
  70
  71 struct ptrace_io_desc32 {
  72         int             piod_op;
  73         uint32_t        piod_offs;
  74         uint32_t        piod_addr;
  75         uint32_t        piod_len;
  76 };
  77
  78 struct ptrace_vm_entry32 {
  79         int             pve_entry;
  80         int             pve_timestamp;
  81         uint32_t        pve_start;
  82         uint32_t        pve_end;
  83         uint32_t        pve_offset;
  84         u_int           pve_prot;
  85         u_int           pve_pathlen;
  86         int32_t         pve_fileid;
  87         u_int           pve_fsid;
  88         uint32_t        pve_path;
  89 };
  90
  91 struct ptrace_lwpinfo32 {
  92         lwpid_t pl_lwpid;       /* LWP described. */
  93         int     pl_event;       /* Event that stopped the LWP. */
  94         int     pl_flags;       /* LWP flags. */
  95         sigset_t        pl_sigmask;     /* LWP signal mask */
  96         sigset_t        pl_siglist;     /* LWP pending signal */
  97         struct siginfo32 pl_siginfo;    /* siginfo for signal */
  98         char    pl_tdname[MAXCOMLEN + 1];       /* LWP name. */
  99         pid_t   pl_child_pid;           /* New child pid */
 100         u_int           pl_syscall_code;
 101         u_int           pl_syscall_narg;
 102 };
 103
 104 #endif
 105
 106 /*
 107  * Functions implemented using PROC_ACTION():
 108  *
 109  * proc_read_regs(proc, regs)
 110  *      Get the current user-visible register set from the process
 111  *      and copy it into the regs structure (<machine/reg.h>).
 112  *      The process is stopped at the time read_regs is called.
 113  *
 114  * proc_write_regs(proc, regs)
 115  *      Update the current register set from the passed in regs
 116  *      structure.  Take care to avoid clobbering special CPU
 117  *      registers or privileged bits in the PSL.
 118  *      Depending on the architecture this may have fix-up work to do,
 119  *      especially if the IAR or PCW are modified.
 120  *      The process is stopped at the time write_regs is called.
 121  *
 122  * proc_read_fpregs, proc_write_fpregs
 123  *      deal with the floating point register set, otherwise as above.
 124  *
 125  * proc_read_dbregs, proc_write_dbregs
 126  *      deal with the processor debug register set, otherwise as above.
 127  *
 128  * proc_sstep(proc)
 129  *      Arrange for the process to trap after executing a single instruction.
 130  */
 131
 132 #define PROC_ACTION(action) do {                                        \
 133         int error;                                                      \
 134                                                                         \
 135         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
 136         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
 137                 error = EIO;                                            \
 138         else                                                            \
 139                 error = (action);                                       \
 140         return (error);                                                 \
 141 } while(0)
 142
 143 int
 144 proc_read_regs(struct thread *td, struct reg *regs)
 145 {
 146
 147         PROC_ACTION(fill_regs(td, regs));
 148 }
 149
 150 int
 151 proc_write_regs(struct thread *td, struct reg *regs)
 152 {
 153
 154         PROC_ACTION(set_regs(td, regs));
 155 }
 156
 157 int
 158 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
 159 {
 160
 161         PROC_ACTION(fill_dbregs(td, dbregs));
 162 }
 163
 164 int
 165 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
 166 {
 167
 168         PROC_ACTION(set_dbregs(td, dbregs));
 169 }
 170
 171 /*
 172  * Ptrace doesn't support fpregs at all, and there are no security holes
 173  * or translations for fpregs, so we can just copy them.
 174  */
 175 int
 176 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
 177 {
 178
 179         PROC_ACTION(fill_fpregs(td, fpregs));
 180 }
 181
 182 int
 183 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
 184 {
 185
 186         PROC_ACTION(set_fpregs(td, fpregs));
 187 }
 188
 189 #ifdef COMPAT_FREEBSD32
 190 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
 191 int
 192 proc_read_regs32(struct thread *td, struct reg32 *regs32)
 193 {
 194
 195         PROC_ACTION(fill_regs32(td, regs32));
 196 }
 197
 198 int
 199 proc_write_regs32(struct thread *td, struct reg32 *regs32)
 200 {
 201
 202         PROC_ACTION(set_regs32(td, regs32));
 203 }
 204
 205 int
 206 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 207 {
 208
 209         PROC_ACTION(fill_dbregs32(td, dbregs32));
 210 }
 211
 212 int
 213 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 214 {
 215
 216         PROC_ACTION(set_dbregs32(td, dbregs32));
 217 }
 218
 219 int
 220 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 221 {
 222
 223         PROC_ACTION(fill_fpregs32(td, fpregs32));
 224 }
 225
 226 int
 227 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 228 {
 229
 230         PROC_ACTION(set_fpregs32(td, fpregs32));
 231 }
 232 #endif
 233
 234 int
 235 proc_sstep(struct thread *td)
 236 {
 237
 238         PROC_ACTION(ptrace_single_step(td));
 239 }
 240
 241 int
 242 proc_rwmem(struct proc *p, struct uio *uio)
 243 {
 244         vm_map_t map;
 245         vm_offset_t pageno;             /* page number */
 246         vm_prot_t reqprot;
 247         int error, fault_flags, page_offset, writing;
 248
 249         /*
 250          * Assert that someone has locked this vmspace.  (Should be
 251          * curthread but we can't assert that.)  This keeps the process
 252          * from exiting out from under us until this operation completes.
 253          */
 254         PROC_ASSERT_HELD(p);
 255         PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 256
 257         /*
 258          * The map we want...
 259          */
 260         map = &p->p_vmspace->vm_map;
 261
 262         /*
 263          * If we are writing, then we request vm_fault() to create a private
 264          * copy of each page.  Since these copies will not be writeable by the
 265          * process, we must explicity request that they be dirtied.
 266          */
 267         writing = uio->uio_rw == UIO_WRITE;
 268         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 269         fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
 270
 271         /*
 272          * Only map in one page at a time.  We don't have to, but it
 273          * makes things easier.  This way is trivial - right?
 274          */
 275         do {
 276                 vm_offset_t uva;
 277                 u_int len;
 278                 vm_page_t m;
 279
 280                 uva = (vm_offset_t)uio->uio_offset;
 281
 282                 /*
 283                  * Get the page number of this segment.
 284                  */
 285                 pageno = trunc_page(uva);
 286                 page_offset = uva - pageno;
 287
 288                 /*
 289                  * How many bytes to copy
 290                  */
 291                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
 292
 293                 /*
 294                  * Fault and hold the page on behalf of the process.
 295                  */
 296                 error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
 297                 if (error != KERN_SUCCESS) {
 298                         if (error == KERN_RESOURCE_SHORTAGE)
 299                                 error = ENOMEM;
 300                         else
 301                                 error = EFAULT;
 302                         break;
 303                 }
 304
 305                 /*
 306                  * Now do the i/o move.
 307                  */
 308                 error = uiomove_fromphys(&m, page_offset, len, uio);
 309
 310                 /* Make the I-cache coherent for breakpoints. */
 311                 if (writing && error == 0) {
 312                         vm_map_lock_read(map);
 313                         if (vm_map_check_protection(map, pageno, pageno +
 314                             PAGE_SIZE, VM_PROT_EXECUTE))
 315                                 vm_sync_icache(map, uva, len);
 316                         vm_map_unlock_read(map);
 317                 }
 318
 319                 /*
 320                  * Release the page.
 321                  */
 322                 vm_page_lock(m);
 323                 vm_page_unhold(m);
 324                 vm_page_unlock(m);
 325
 326         } while (error == 0 && uio->uio_resid > 0);
 327
 328         return (error);
 329 }
 330
 331 static ssize_t
 332 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 333     size_t len, enum uio_rw rw)
 334 {
 335         struct iovec iov;
 336         struct uio uio;
 337         ssize_t slen;
 338         int error;
 339
 340         MPASS(len < SSIZE_MAX);
 341         slen = (ssize_t)len;
 342
 343         iov.iov_base = (caddr_t)buf;
 344         iov.iov_len = len;
 345         uio.uio_iov = &iov;
 346         uio.uio_iovcnt = 1;
 347         uio.uio_offset = va;
 348         uio.uio_resid = slen;
 349         uio.uio_segflg = UIO_SYSSPACE;
 350         uio.uio_rw = rw;
 351         uio.uio_td = td;
 352         error = proc_rwmem(p, &uio);
 353         if (uio.uio_resid == slen)
 354                 return (-1);
 355         return (slen - uio.uio_resid);
 356 }
 357
 358 ssize_t
 359 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 360     size_t len)
 361 {
 362
 363         return (proc_iop(td, p, va, buf, len, UIO_READ));
 364 }
 365
 366 ssize_t
 367 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 368     size_t len)
 369 {
 370
 371         return (proc_iop(td, p, va, buf, len, UIO_WRITE));
 372 }
 373
 374 static int
 375 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 376 {
 377         struct vattr vattr;
 378         vm_map_t map;
 379         vm_map_entry_t entry;
 380         vm_object_t obj, tobj, lobj;
 381         struct vmspace *vm;
 382         struct vnode *vp;
 383         char *freepath, *fullpath;
 384         u_int pathlen;
 385         int error, index;
 386
 387         error = 0;
 388         obj = NULL;
 389
 390         vm = vmspace_acquire_ref(p);
 391         map = &vm->vm_map;
 392         vm_map_lock_read(map);
 393
 394         do {
 395                 entry = map->header.next;
 396                 index = 0;
 397                 while (index < pve->pve_entry && entry != &map->header) {
 398                         entry = entry->next;
 399                         index++;
 400                 }
 401                 if (index != pve->pve_entry) {
 402                         error = EINVAL;
 403                         break;
 404                 }
 405                 while (entry != &map->header &&
 406                     (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
 407                         entry = entry->next;
 408                         index++;
 409                 }
 410                 if (entry == &map->header) {
 411                         error = ENOENT;
 412                         break;
 413                 }
 414
 415                 /* We got an entry. */
 416                 pve->pve_entry = index + 1;
 417                 pve->pve_timestamp = map->timestamp;
 418                 pve->pve_start = entry->start;
 419                 pve->pve_end = entry->end - 1;
 420                 pve->pve_offset = entry->offset;
 421                 pve->pve_prot = entry->protection;
 422
 423                 /* Backing object's path needed? */
 424                 if (pve->pve_pathlen == 0)
 425                         break;
 426
 427                 pathlen = pve->pve_pathlen;
 428                 pve->pve_pathlen = 0;
 429
 430                 obj = entry->object.vm_object;
 431                 if (obj != NULL)
 432                         VM_OBJECT_RLOCK(obj);
 433         } while (0);
 434
 435         vm_map_unlock_read(map);
 436         vmspace_free(vm);
 437
 438         pve->pve_fsid = VNOVAL;
 439         pve->pve_fileid = VNOVAL;
 440
 441         if (error == 0 && obj != NULL) {
 442                 lobj = obj;
 443                 for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
 444                         if (tobj != obj)
 445                                 VM_OBJECT_RLOCK(tobj);
 446                         if (lobj != obj)
 447                                 VM_OBJECT_RUNLOCK(lobj);
 448                         lobj = tobj;
 449                         pve->pve_offset += tobj->backing_object_offset;
 450                 }
 451                 vp = vm_object_vnode(lobj);
 452                 if (vp != NULL)
 453                         vref(vp);
 454                 if (lobj != obj)
 455                         VM_OBJECT_RUNLOCK(lobj);
 456                 VM_OBJECT_RUNLOCK(obj);
 457
 458                 if (vp != NULL) {
 459                         freepath = NULL;
 460                         fullpath = NULL;
 461                         vn_fullpath(td, vp, &fullpath, &freepath);
 462                         vn_lock(vp, LK_SHARED | LK_RETRY);
 463                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
 464                                 pve->pve_fileid = vattr.va_fileid;
 465                                 pve->pve_fsid = vattr.va_fsid;
 466                         }
 467                         vput(vp);
 468
 469                         if (fullpath != NULL) {
 470                                 pve->pve_pathlen = strlen(fullpath) + 1;
 471                                 if (pve->pve_pathlen <= pathlen) {
 472                                         error = copyout(fullpath, pve->pve_path,
 473                                             pve->pve_pathlen);
 474                                 } else
 475                                         error = ENAMETOOLONG;
 476                         }
 477                         if (freepath != NULL)
 478                                 free(freepath, M_TEMP);
 479                 }
 480         }
 481         if (error == 0)
 482                 CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
 483                     p->p_pid, pve->pve_entry, pve->pve_start);
 484
 485         return (error);
 486 }
 487
 488 #ifdef COMPAT_FREEBSD32
 489 static int
 490 ptrace_vm_entry32(struct thread *td, struct proc *p,
 491     struct ptrace_vm_entry32 *pve32)
 492 {
 493         struct ptrace_vm_entry pve;
 494         int error;
 495
 496         pve.pve_entry = pve32->pve_entry;
 497         pve.pve_pathlen = pve32->pve_pathlen;
 498         pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
 499
 500         error = ptrace_vm_entry(td, p, &pve);
 501         if (error == 0) {
 502                 pve32->pve_entry = pve.pve_entry;
 503                 pve32->pve_timestamp = pve.pve_timestamp;
 504                 pve32->pve_start = pve.pve_start;
 505                 pve32->pve_end = pve.pve_end;
 506                 pve32->pve_offset = pve.pve_offset;
 507                 pve32->pve_prot = pve.pve_prot;
 508                 pve32->pve_fileid = pve.pve_fileid;
 509                 pve32->pve_fsid = pve.pve_fsid;
 510         }
 511
 512         pve32->pve_pathlen = pve.pve_pathlen;
 513         return (error);
 514 }
 515
 516 static void
 517 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
 518     struct ptrace_lwpinfo32 *pl32)
 519 {
 520
 521         pl32->pl_lwpid = pl->pl_lwpid;
 522         pl32->pl_event = pl->pl_event;
 523         pl32->pl_flags = pl->pl_flags;
 524         pl32->pl_sigmask = pl->pl_sigmask;
 525         pl32->pl_siglist = pl->pl_siglist;
 526         siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
 527         strcpy(pl32->pl_tdname, pl->pl_tdname);
 528         pl32->pl_child_pid = pl->pl_child_pid;
 529         pl32->pl_syscall_code = pl->pl_syscall_code;
 530         pl32->pl_syscall_narg = pl->pl_syscall_narg;
 531 }
 532 #endif /* COMPAT_FREEBSD32 */
 533
 534 /*
 535  * Process debugging system call.
 536  */
 537 #ifndef _SYS_SYSPROTO_H_
 538 struct ptrace_args {
 539         int     req;
 540         pid_t   pid;
 541         caddr_t addr;
 542         int     data;
 543 };
 544 #endif
 545
 546 #ifdef COMPAT_FREEBSD32
 547 /*
 548  * This CPP subterfuge is to try and reduce the number of ifdefs in
 549  * the body of the code.
 550  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
 551  * becomes either:
 552  *   copyin(uap->addr, &r.reg, sizeof r.reg);
 553  * or
 554  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
 555  * .. except this is done at runtime.
 556  */
 557 #define COPYIN(u, k, s)         wrap32 ? \
 558         copyin(u, k ## 32, s ## 32) : \
 559         copyin(u, k, s)
 560 #define COPYOUT(k, u, s)        wrap32 ? \
 561         copyout(k ## 32, u, s ## 32) : \
 562         copyout(k, u, s)
 563 #else
 564 #define COPYIN(u, k, s)         copyin(u, k, s)
 565 #define COPYOUT(k, u, s)        copyout(k, u, s)
 566 #endif
 567 int
 568 sys_ptrace(struct thread *td, struct ptrace_args *uap)
 569 {
 570         /*
 571          * XXX this obfuscation is to reduce stack usage, but the register
 572          * structs may be too large to put on the stack anyway.
 573          */
 574         union {
 575                 struct ptrace_io_desc piod;
 576                 struct ptrace_lwpinfo pl;
 577                 struct ptrace_vm_entry pve;
 578                 struct dbreg dbreg;
 579                 struct fpreg fpreg;
 580                 struct reg reg;
 581 #ifdef COMPAT_FREEBSD32
 582                 struct dbreg32 dbreg32;
 583                 struct fpreg32 fpreg32;
 584                 struct reg32 reg32;
 585                 struct ptrace_io_desc32 piod32;
 586                 struct ptrace_lwpinfo32 pl32;
 587                 struct ptrace_vm_entry32 pve32;
 588 #endif
 589         } r;
 590         void *addr;
 591         int error = 0;
 592 #ifdef COMPAT_FREEBSD32
 593         int wrap32 = 0;
 594
 595         if (SV_CURPROC_FLAG(SV_ILP32))
 596                 wrap32 = 1;
 597 #endif
 598         AUDIT_ARG_PID(uap->pid);
 599         AUDIT_ARG_CMD(uap->req);
 600         AUDIT_ARG_VALUE(uap->data);
 601         addr = &r;
 602         switch (uap->req) {
 603         case PT_GETREGS:
 604         case PT_GETFPREGS:
 605         case PT_GETDBREGS:
 606         case PT_LWPINFO:
 607                 break;
 608         case PT_SETREGS:
 609                 error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
 610                 break;
 611         case PT_SETFPREGS:
 612                 error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
 613                 break;
 614         case PT_SETDBREGS:
 615                 error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
 616                 break;
 617         case PT_IO:
 618                 error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
 619                 break;
 620         case PT_VM_ENTRY:
 621                 error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
 622                 break;
 623         default:
 624                 addr = uap->addr;
 625                 break;
 626         }
 627         if (error)
 628                 return (error);
 629
 630         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
 631         if (error)
 632                 return (error);
 633
 634         switch (uap->req) {
 635         case PT_VM_ENTRY:
 636                 error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
 637                 break;
 638         case PT_IO:
 639                 error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
 640                 break;
 641         case PT_GETREGS:
 642                 error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
 643                 break;
 644         case PT_GETFPREGS:
 645                 error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
 646                 break;
 647         case PT_GETDBREGS:
 648                 error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
 649                 break;
 650         case PT_LWPINFO:
 651                 error = copyout(&r.pl, uap->addr, uap->data);
 652                 break;
 653         }
 654
 655         return (error);
 656 }
 657 #undef COPYIN
 658 #undef COPYOUT
 659
 660 #ifdef COMPAT_FREEBSD32
 661 /*
 662  *   PROC_READ(regs, td2, addr);
 663  * becomes either:
 664  *   proc_read_regs(td2, addr);
 665  * or
 666  *   proc_read_regs32(td2, addr);
 667  * .. except this is done at runtime.  There is an additional
 668  * complication in that PROC_WRITE disallows 32 bit consumers
 669  * from writing to 64 bit address space targets.
 670  */
 671 #define PROC_READ(w, t, a)      wrap32 ? \
 672         proc_read_ ## w ## 32(t, a) : \
 673         proc_read_ ## w (t, a)
 674 #define PROC_WRITE(w, t, a)     wrap32 ? \
 675         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
 676         proc_write_ ## w (t, a)
 677 #else
 678 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
 679 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
 680 #endif
 681
 682 int
 683 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 684 {
 685         struct iovec iov;
 686         struct uio uio;
 687         struct proc *curp, *p, *pp;
 688         struct thread *td2 = NULL, *td3;
 689         struct ptrace_io_desc *piod = NULL;
 690         struct ptrace_lwpinfo *pl;
 691         int error, num, tmp;
 692         int proctree_locked = 0;
 693         lwpid_t tid = 0, *buf;
 694 #ifdef COMPAT_FREEBSD32
 695         int wrap32 = 0, safe = 0;
 696         struct ptrace_io_desc32 *piod32 = NULL;
 697         struct ptrace_lwpinfo32 *pl32 = NULL;
 698         struct ptrace_lwpinfo plr;
 699 #endif
 700
 701         curp = td->td_proc;
 702
 703         /* Lock proctree before locking the process. */
 704         switch (req) {
 705         case PT_TRACE_ME:
 706         case PT_ATTACH:
 707         case PT_STEP:
 708         case PT_CONTINUE:
 709         case PT_TO_SCE:
 710         case PT_TO_SCX:
 711         case PT_SYSCALL:
 712         case PT_FOLLOW_FORK:
 713         case PT_DETACH:
 714                 sx_xlock(&proctree_lock);
 715                 proctree_locked = 1;
 716                 break;
 717         default:
 718                 break;
 719         }
 720
 721         if (req == PT_TRACE_ME) {
 722                 p = td->td_proc;
 723                 PROC_LOCK(p);
 724         } else {
 725                 if (pid <= PID_MAX) {
 726                         if ((p = pfind(pid)) == NULL) {
 727                                 if (proctree_locked)
 728                                         sx_xunlock(&proctree_lock);
 729                                 return (ESRCH);
 730                         }
 731                 } else {
 732                         td2 = tdfind(pid, -1);
 733                         if (td2 == NULL) {
 734                                 if (proctree_locked)
 735                                         sx_xunlock(&proctree_lock);
 736                                 return (ESRCH);
 737                         }
 738                         p = td2->td_proc;
 739                         tid = pid;
 740                         pid = p->p_pid;
 741                 }
 742         }
 743         AUDIT_ARG_PROCESS(p);
 744
 745         if ((p->p_flag & P_WEXIT) != 0) {
 746                 error = ESRCH;
 747                 goto fail;
 748         }
 749         if ((error = p_cansee(td, p)) != 0)
 750                 goto fail;
 751
 752         if ((error = p_candebug(td, p)) != 0)
 753                 goto fail;
 754
 755         /*
 756          * System processes can't be debugged.
 757          */
 758         if ((p->p_flag & P_SYSTEM) != 0) {
 759                 error = EINVAL;
 760                 goto fail;
 761         }
 762
 763         if (tid == 0) {
 764                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
 765                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
 766                         td2 = p->p_xthread;
 767                 } else {
 768                         td2 = FIRST_THREAD_IN_PROC(p);
 769                 }
 770                 tid = td2->td_tid;
 771         }
 772
 773 #ifdef COMPAT_FREEBSD32
 774         /*
 775          * Test if we're a 32 bit client and what the target is.
 776          * Set the wrap controls accordingly.
 777          */
 778         if (SV_CURPROC_FLAG(SV_ILP32)) {
 779                 if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
 780                         safe = 1;
 781                 wrap32 = 1;
 782         }
 783 #endif
 784         /*
 785          * Permissions check
 786          */
 787         switch (req) {
 788         case PT_TRACE_ME:
 789                 /*
 790                  * Always legal, when there is a parent process which
 791                  * could trace us.  Otherwise, reject.
 792                  */
 793                 if ((p->p_flag & P_TRACED) != 0) {
 794                         error = EBUSY;
 795                         goto fail;
 796                 }
 797                 if (p->p_pptr == initproc) {
 798                         error = EPERM;
 799                         goto fail;
 800                 }
 801                 break;
 802
 803         case PT_ATTACH:
 804                 /* Self */
 805                 if (p == td->td_proc) {
 806                         error = EINVAL;
 807                         goto fail;
 808                 }
 809
 810                 /* Already traced */
 811                 if (p->p_flag & P_TRACED) {
 812                         error = EBUSY;
 813                         goto fail;
 814                 }
 815
 816                 /* Can't trace an ancestor if you're being traced. */
 817                 if (curp->p_flag & P_TRACED) {
 818                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
 819                                 if (pp == p) {
 820                                         error = EINVAL;
 821                                         goto fail;
 822                                 }
 823                         }
 824                 }
 825
 826
 827                 /* OK */
 828                 break;
 829
 830         case PT_CLEARSTEP:
 831                 /* Allow thread to clear single step for itself */
 832                 if (td->td_tid == tid)
 833                         break;
 834
 835                 /* FALLTHROUGH */
 836         default:
 837                 /* not being traced... */
 838                 if ((p->p_flag & P_TRACED) == 0) {
 839                         error = EPERM;
 840                         goto fail;
 841                 }
 842
 843                 /* not being traced by YOU */
 844                 if (p->p_pptr != td->td_proc) {
 845                         error = EBUSY;
 846                         goto fail;
 847                 }
 848
 849                 /* not currently stopped */
 850                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
 851                     p->p_suspcount != p->p_numthreads  ||
 852                     (p->p_flag & P_WAITED) == 0) {
 853                         error = EBUSY;
 854                         goto fail;
 855                 }
 856
 857                 if ((p->p_flag & P_STOPPED_TRACE) == 0) {
 858                         static int count = 0;
 859                         if (count++ == 0)
 860                                 printf("P_STOPPED_TRACE not set.\n");
 861                 }
 862
 863                 /* OK */
 864                 break;
 865         }
 866
 867         /* Keep this process around until we finish this request. */
 868         _PHOLD(p);
 869
 870 #ifdef FIX_SSTEP
 871         /*
 872          * Single step fixup ala procfs
 873          */
 874         FIX_SSTEP(td2);
 875 #endif
 876
 877         /*
 878          * Actually do the requests
 879          */
 880
 881         td->td_retval[0] = 0;
 882
 883         switch (req) {
 884         case PT_TRACE_ME:
 885                 /* set my trace flag and "owner" so it can read/write me */
 886                 p->p_flag |= P_TRACED;
 887                 if (p->p_flag & P_PPWAIT)
 888                         p->p_flag |= P_PPTRACE;
 889                 p->p_oppid = p->p_pptr->p_pid;
 890                 CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
 891                 break;
 892
 893         case PT_ATTACH:
 894                 /* security check done above */
 895                 /*
 896                  * It would be nice if the tracing relationship was separate
 897                  * from the parent relationship but that would require
 898                  * another set of links in the proc struct or for "wait"
 899                  * to scan the entire proc table.  To make life easier,
 900                  * we just re-parent the process we're trying to trace.
 901                  * The old parent is remembered so we can put things back
 902                  * on a "detach".
 903                  */
 904                 p->p_flag |= P_TRACED;
 905                 p->p_oppid = p->p_pptr->p_pid;
 906                 if (p->p_pptr != td->td_proc) {
 907                         proc_reparent(p, td->td_proc);
 908                 }
 909                 data = SIGSTOP;
 910                 CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
 911                     p->p_oppid);
 912                 goto sendsig;   /* in PT_CONTINUE below */
 913
 914         case PT_CLEARSTEP:
 915                 CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
 916                     p->p_pid);
 917                 error = ptrace_clear_single_step(td2);
 918                 break;
 919
 920         case PT_SETSTEP:
 921                 CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
 922                     p->p_pid);
 923                 error = ptrace_single_step(td2);
 924                 break;
 925
 926         case PT_SUSPEND:
 927                 CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
 928                     p->p_pid);
 929                 td2->td_dbgflags |= TDB_SUSPEND;
 930                 thread_lock(td2);
 931                 td2->td_flags |= TDF_NEEDSUSPCHK;
 932                 thread_unlock(td2);
 933                 break;
 934
 935         case PT_RESUME:
 936                 CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
 937                     p->p_pid);
 938                 td2->td_dbgflags &= ~TDB_SUSPEND;
 939                 break;
 940
 941         case PT_FOLLOW_FORK:
 942                 CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
 943                     p->p_flag & P_FOLLOWFORK ? "enabled" : "disabled",
 944                     data ? "enabled" : "disabled");
 945                 if (data)
 946                         p->p_flag |= P_FOLLOWFORK;
 947                 else
 948                         p->p_flag &= ~P_FOLLOWFORK;
 949                 break;
 950
 951         case PT_STEP:
 952         case PT_CONTINUE:
 953         case PT_TO_SCE:
 954         case PT_TO_SCX:
 955         case PT_SYSCALL:
 956         case PT_DETACH:
 957                 /* Zero means do not send any signal */
 958                 if (data < 0 || data > _SIG_MAXSIG) {
 959                         error = EINVAL;
 960                         break;
 961                 }
 962
 963                 switch (req) {
 964                 case PT_STEP:
 965                         CTR2(KTR_PTRACE, "PT_STEP: tid %d (pid %d)",
 966                             td2->td_tid, p->p_pid);
 967                         error = ptrace_single_step(td2);
 968                         if (error)
 969                                 goto out;
 970                         break;
 971                 case PT_CONTINUE:
 972                 case PT_TO_SCE:
 973                 case PT_TO_SCX:
 974                 case PT_SYSCALL:
 975                         if (addr != (void *)1) {
 976                                 error = ptrace_set_pc(td2,
 977                                     (u_long)(uintfptr_t)addr);
 978                                 if (error)
 979                                         goto out;
 980                         }
 981                         switch (req) {
 982                         case PT_TO_SCE:
 983                                 p->p_stops |= S_PT_SCE;
 984                                 CTR4(KTR_PTRACE,
 985                     "PT_TO_SCE: pid %d, stops = %#x, PC = %#lx, sig = %d",
 986                                     p->p_pid, p->p_stops,
 987                                     (u_long)(uintfptr_t)addr, data);
 988                                 break;
 989                         case PT_TO_SCX:
 990                                 p->p_stops |= S_PT_SCX;
 991                                 CTR4(KTR_PTRACE,
 992                     "PT_TO_SCX: pid %d, stops = %#x, PC = %#lx, sig = %d",
 993                                     p->p_pid, p->p_stops,
 994                                     (u_long)(uintfptr_t)addr, data);
 995                                 break;
 996                         case PT_SYSCALL:
 997                                 p->p_stops |= S_PT_SCE | S_PT_SCX;
 998                                 CTR4(KTR_PTRACE,
 999                     "PT_SYSCALL: pid %d, stops = %#x, PC = %#lx, sig = %d",
1000                                     p->p_pid, p->p_stops,
1001                                     (u_long)(uintfptr_t)addr, data);
1002                                 break;
1003                         case PT_CONTINUE:
1004                                 CTR3(KTR_PTRACE,
1005                                     "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1006                                     p->p_pid, (u_long)(uintfptr_t)addr, data);
1007                                 break;
1008                         }
1009                         break;
1010                 case PT_DETACH:
1011                         /*
1012                          * Reset the process parent.
1013                          *
1014                          * NB: This clears P_TRACED before reparenting
1015                          * a detached process back to its original
1016                          * parent.  Otherwise the debugee will be set
1017                          * as an orphan of the debugger.
1018                          */
1019                         p->p_flag &= ~(P_TRACED | P_WAITED | P_FOLLOWFORK);
1020                         if (p->p_oppid != p->p_pptr->p_pid) {
1021                                 PROC_LOCK(p->p_pptr);
1022                                 sigqueue_take(p->p_ksi);
1023                                 PROC_UNLOCK(p->p_pptr);
1024
1025                                 pp = proc_realparent(p);
1026                                 proc_reparent(p, pp);
1027                                 if (pp == initproc)
1028                                         p->p_sigparent = SIGCHLD;
1029                                 CTR3(KTR_PTRACE,
1030                             "PT_DETACH: pid %d reparented to pid %d, sig %d",
1031                                     p->p_pid, pp->p_pid, data);
1032                         } else
1033                                 CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1034                                     p->p_pid, data);
1035                         p->p_oppid = 0;
1036                         p->p_stops = 0;
1037
1038                         /* should we send SIGCHLD? */
1039                         /* childproc_continued(p); */
1040                         break;
1041                 }
1042
1043         sendsig:
1044                 if (proctree_locked) {
1045                         sx_xunlock(&proctree_lock);
1046                         proctree_locked = 0;
1047                 }
1048                 p->p_xsig = data;
1049                 p->p_xthread = NULL;
1050                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
1051                         /* deliver or queue signal */
1052                         td2->td_dbgflags &= ~TDB_XSIG;
1053                         td2->td_xsig = data;
1054
1055                         if (req == PT_DETACH) {
1056                                 FOREACH_THREAD_IN_PROC(p, td3)
1057                                         td3->td_dbgflags &= ~TDB_SUSPEND;
1058                         }
1059                         /*
1060                          * unsuspend all threads, to not let a thread run,
1061                          * you should use PT_SUSPEND to suspend it before
1062                          * continuing process.
1063                          */
1064                         PROC_SLOCK(p);
1065                         p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
1066                         thread_unsuspend(p);
1067                         PROC_SUNLOCK(p);
1068                         if (req == PT_ATTACH)
1069                                 kern_psignal(p, data);
1070                 } else {
1071                         if (data)
1072                                 kern_psignal(p, data);
1073                 }
1074                 break;
1075
1076         case PT_WRITE_I:
1077         case PT_WRITE_D:
1078                 td2->td_dbgflags |= TDB_USERWR;
1079                 PROC_UNLOCK(p);
1080                 error = 0;
1081                 if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1082                     sizeof(int)) != sizeof(int))
1083                         error = ENOMEM;
1084                 else
1085                         CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1086                             p->p_pid, addr, data);
1087                 PROC_LOCK(p);
1088                 break;
1089
1090         case PT_READ_I:
1091         case PT_READ_D:
1092                 PROC_UNLOCK(p);
1093                 error = tmp = 0;
1094                 if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1095                     sizeof(int)) != sizeof(int))
1096                         error = ENOMEM;
1097                 else
1098                         CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1099                             p->p_pid, addr, tmp);
1100                 td->td_retval[0] = tmp;
1101                 PROC_LOCK(p);
1102                 break;
1103
1104         case PT_IO:
1105 #ifdef COMPAT_FREEBSD32
1106                 if (wrap32) {
1107                         piod32 = addr;
1108                         iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1109                         iov.iov_len = piod32->piod_len;
1110                         uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1111                         uio.uio_resid = piod32->piod_len;
1112                 } else
1113 #endif
1114                 {
1115                         piod = addr;
1116                         iov.iov_base = piod->piod_addr;
1117                         iov.iov_len = piod->piod_len;
1118                         uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1119                         uio.uio_resid = piod->piod_len;
1120                 }
1121                 uio.uio_iov = &iov;
1122                 uio.uio_iovcnt = 1;
1123                 uio.uio_segflg = UIO_USERSPACE;
1124                 uio.uio_td = td;
1125 #ifdef COMPAT_FREEBSD32
1126                 tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1127 #else
1128                 tmp = piod->piod_op;
1129 #endif
1130                 switch (tmp) {
1131                 case PIOD_READ_D:
1132                 case PIOD_READ_I:
1133                         CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1134                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1135                         uio.uio_rw = UIO_READ;
1136                         break;
1137                 case PIOD_WRITE_D:
1138                 case PIOD_WRITE_I:
1139                         CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1140                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1141                         td2->td_dbgflags |= TDB_USERWR;
1142                         uio.uio_rw = UIO_WRITE;
1143                         break;
1144                 default:
1145                         error = EINVAL;
1146                         goto out;
1147                 }
1148                 PROC_UNLOCK(p);
1149                 error = proc_rwmem(p, &uio);
1150 #ifdef COMPAT_FREEBSD32
1151                 if (wrap32)
1152                         piod32->piod_len -= uio.uio_resid;
1153                 else
1154 #endif
1155                         piod->piod_len -= uio.uio_resid;
1156                 PROC_LOCK(p);
1157                 break;
1158
1159         case PT_KILL:
1160                 CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1161                 data = SIGKILL;
1162                 goto sendsig;   /* in PT_CONTINUE above */
1163
1164         case PT_SETREGS:
1165                 CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1166                     p->p_pid);
1167                 td2->td_dbgflags |= TDB_USERWR;
1168                 error = PROC_WRITE(regs, td2, addr);
1169                 break;
1170
1171         case PT_GETREGS:
1172                 CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1173                     p->p_pid);
1174                 error = PROC_READ(regs, td2, addr);
1175                 break;
1176
1177         case PT_SETFPREGS:
1178                 CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1179                     p->p_pid);
1180                 td2->td_dbgflags |= TDB_USERWR;
1181                 error = PROC_WRITE(fpregs, td2, addr);
1182                 break;
1183
1184         case PT_GETFPREGS:
1185                 CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1186                     p->p_pid);
1187                 error = PROC_READ(fpregs, td2, addr);
1188                 break;
1189
1190         case PT_SETDBREGS:
1191                 CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1192                     p->p_pid);
1193                 td2->td_dbgflags |= TDB_USERWR;
1194                 error = PROC_WRITE(dbregs, td2, addr);
1195                 break;
1196
1197         case PT_GETDBREGS:
1198                 CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1199                     p->p_pid);
1200                 error = PROC_READ(dbregs, td2, addr);
1201                 break;
1202
1203         case PT_LWPINFO:
1204                 if (data <= 0 ||
1205 #ifdef COMPAT_FREEBSD32
1206                     (!wrap32 && data > sizeof(*pl)) ||
1207                     (wrap32 && data > sizeof(*pl32))) {
1208 #else
1209                     data > sizeof(*pl)) {
1210 #endif
1211                         error = EINVAL;
1212                         break;
1213                 }
1214 #ifdef COMPAT_FREEBSD32
1215                 if (wrap32) {
1216                         pl = &plr;
1217                         pl32 = addr;
1218                 } else
1219 #endif
1220                 pl = addr;
1221                 pl->pl_lwpid = td2->td_tid;
1222                 pl->pl_event = PL_EVENT_NONE;
1223                 pl->pl_flags = 0;
1224                 if (td2->td_dbgflags & TDB_XSIG) {
1225                         pl->pl_event = PL_EVENT_SIGNAL;
1226                         if (td2->td_dbgksi.ksi_signo != 0 &&
1227 #ifdef COMPAT_FREEBSD32
1228                             ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1229                             pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1230                             (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1231                             pl_siginfo) + sizeof(struct siginfo32)))
1232 #else
1233                             data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1234                             + sizeof(pl->pl_siginfo)
1235 #endif
1236                         ){
1237                                 pl->pl_flags |= PL_FLAG_SI;
1238                                 pl->pl_siginfo = td2->td_dbgksi.ksi_info;
1239                         }
1240                 }
1241                 if ((pl->pl_flags & PL_FLAG_SI) == 0)
1242                         bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
1243                 if (td2->td_dbgflags & TDB_SCE)
1244                         pl->pl_flags |= PL_FLAG_SCE;
1245                 else if (td2->td_dbgflags & TDB_SCX)
1246                         pl->pl_flags |= PL_FLAG_SCX;
1247                 if (td2->td_dbgflags & TDB_EXEC)
1248                         pl->pl_flags |= PL_FLAG_EXEC;
1249                 if (td2->td_dbgflags & TDB_FORK) {
1250                         pl->pl_flags |= PL_FLAG_FORKED;
1251                         pl->pl_child_pid = td2->td_dbg_forked;
1252                 }
1253                 if (td2->td_dbgflags & TDB_CHILD)
1254                         pl->pl_flags |= PL_FLAG_CHILD;
1255                 pl->pl_sigmask = td2->td_sigmask;
1256                 pl->pl_siglist = td2->td_siglist;
1257                 strcpy(pl->pl_tdname, td2->td_name);
1258                 if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1259                         pl->pl_syscall_code = td2->td_dbg_sc_code;
1260                         pl->pl_syscall_narg = td2->td_dbg_sc_narg;
1261                 } else {
1262                         pl->pl_syscall_code = 0;
1263                         pl->pl_syscall_narg = 0;
1264                 }
1265 #ifdef COMPAT_FREEBSD32
1266                 if (wrap32)
1267                         ptrace_lwpinfo_to32(pl, pl32);
1268 #endif
1269                 CTR6(KTR_PTRACE,
1270     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1271                     td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1272                     pl->pl_child_pid, pl->pl_syscall_code);
1273                 break;
1274
1275         case PT_GETNUMLWPS:
1276                 CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1277                     p->p_numthreads);
1278                 td->td_retval[0] = p->p_numthreads;
1279                 break;
1280
1281         case PT_GETLWPLIST:
1282                 CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1283                     p->p_pid, data, p->p_numthreads);
1284                 if (data <= 0) {
1285                         error = EINVAL;
1286                         break;
1287                 }
1288                 num = imin(p->p_numthreads, data);
1289                 PROC_UNLOCK(p);
1290                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1291                 tmp = 0;
1292                 PROC_LOCK(p);
1293                 FOREACH_THREAD_IN_PROC(p, td2) {
1294                         if (tmp >= num)
1295                                 break;
1296                         buf[tmp++] = td2->td_tid;
1297                 }
1298                 PROC_UNLOCK(p);
1299                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1300                 free(buf, M_TEMP);
1301                 if (!error)
1302                         td->td_retval[0] = tmp;
1303                 PROC_LOCK(p);
1304                 break;
1305
1306         case PT_VM_TIMESTAMP:
1307                 CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1308                     p->p_pid, p->p_vmspace->vm_map.timestamp);
1309                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1310                 break;
1311
1312         case PT_VM_ENTRY:
1313                 PROC_UNLOCK(p);
1314 #ifdef COMPAT_FREEBSD32
1315                 if (wrap32)
1316                         error = ptrace_vm_entry32(td, p, addr);
1317                 else
1318 #endif
1319                 error = ptrace_vm_entry(td, p, addr);
1320                 PROC_LOCK(p);
1321                 break;
1322
1323         default:
1324 #ifdef __HAVE_PTRACE_MACHDEP
1325                 if (req >= PT_FIRSTMACH) {
1326                         PROC_UNLOCK(p);
1327                         error = cpu_ptrace(td2, req, addr, data);
1328                         PROC_LOCK(p);
1329                 } else
1330 #endif
1331                         /* Unknown request. */
1332                         error = EINVAL;
1333                 break;
1334         }
1335
1336 out:
1337         /* Drop our hold on this process now that the request has completed. */
1338         _PRELE(p);
1339 fail:
1340         PROC_UNLOCK(p);
1341         if (proctree_locked)
1342                 sx_xunlock(&proctree_lock);
1343         return (error);
1344 }
1345 #undef PROC_READ
1346 #undef PROC_WRITE
1347
1348 /*
1349  * Stop a process because of a debugging event;
1350  * stay stopped until p->p_step is cleared
1351  * (cleared by PIOCCONT in procfs).
1352  */
1353 void
1354 stopevent(struct proc *p, unsigned int event, unsigned int val)
1355 {
1356
1357         PROC_LOCK_ASSERT(p, MA_OWNED);
1358         p->p_step = 1;
1359         CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1360             val);
1361         do {
1362                 if (event != S_EXIT)
1363                         p->p_xsig = val;
1364                 p->p_xthread = NULL;
1365                 p->p_stype = event;     /* Which event caused the stop? */
1366                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
1367                 msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1368         } while (p->p_step);
1369 }