sys/kern/sys_process.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-4-Clause
   3  *
   4  * Copyright (c) 1994, Sean Eric Fagan
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Sean Eric Fagan.
  18  * 4. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include "opt_compat.h"
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/syscallsubr.h>
  44 #include <sys/sysent.h>
  45 #include <sys/sysproto.h>
  46 #include <sys/pioctl.h>
  47 #include <sys/priv.h>
  48 #include <sys/proc.h>
  49 #include <sys/vnode.h>
  50 #include <sys/ptrace.h>
  51 #include <sys/rwlock.h>
  52 #include <sys/sx.h>
  53 #include <sys/malloc.h>
  54 #include <sys/signalvar.h>
  55
  56 #include <machine/reg.h>
  57
  58 #include <security/audit/audit.h>
  59
  60 #include <vm/vm.h>
  61 #include <vm/pmap.h>
  62 #include <vm/vm_extern.h>
  63 #include <vm/vm_map.h>
  64 #include <vm/vm_kern.h>
  65 #include <vm/vm_object.h>
  66 #include <vm/vm_page.h>
  67 #include <vm/vm_param.h>
  68
  69 #ifdef COMPAT_FREEBSD32
  70 #include <sys/procfs.h>
  71 #include <compat/freebsd32/freebsd32_signal.h>
  72
  73 struct ptrace_io_desc32 {
  74         int             piod_op;
  75         uint32_t        piod_offs;
  76         uint32_t        piod_addr;
  77         uint32_t        piod_len;
  78 };
  79
  80 struct ptrace_vm_entry32 {
  81         int             pve_entry;
  82         int             pve_timestamp;
  83         uint32_t        pve_start;
  84         uint32_t        pve_end;
  85         uint32_t        pve_offset;
  86         u_int           pve_prot;
  87         u_int           pve_pathlen;
  88         int32_t         pve_fileid;
  89         u_int           pve_fsid;
  90         uint32_t        pve_path;
  91 };
  92 #endif
  93
  94 /*
  95  * Functions implemented using PROC_ACTION():
  96  *
  97  * proc_read_regs(proc, regs)
  98  *      Get the current user-visible register set from the process
  99  *      and copy it into the regs structure (<machine/reg.h>).
 100  *      The process is stopped at the time read_regs is called.
 101  *
 102  * proc_write_regs(proc, regs)
 103  *      Update the current register set from the passed in regs
 104  *      structure.  Take care to avoid clobbering special CPU
 105  *      registers or privileged bits in the PSL.
 106  *      Depending on the architecture this may have fix-up work to do,
 107  *      especially if the IAR or PCW are modified.
 108  *      The process is stopped at the time write_regs is called.
 109  *
 110  * proc_read_fpregs, proc_write_fpregs
 111  *      deal with the floating point register set, otherwise as above.
 112  *
 113  * proc_read_dbregs, proc_write_dbregs
 114  *      deal with the processor debug register set, otherwise as above.
 115  *
 116  * proc_sstep(proc)
 117  *      Arrange for the process to trap after executing a single instruction.
 118  */
 119
 120 #define PROC_ACTION(action) do {                                        \
 121         int error;                                                      \
 122                                                                         \
 123         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
 124         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
 125                 error = EIO;                                            \
 126         else                                                            \
 127                 error = (action);                                       \
 128         return (error);                                                 \
 129 } while(0)
 130
 131 int
 132 proc_read_regs(struct thread *td, struct reg *regs)
 133 {
 134
 135         PROC_ACTION(fill_regs(td, regs));
 136 }
 137
 138 int
 139 proc_write_regs(struct thread *td, struct reg *regs)
 140 {
 141
 142         PROC_ACTION(set_regs(td, regs));
 143 }
 144
 145 int
 146 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
 147 {
 148
 149         PROC_ACTION(fill_dbregs(td, dbregs));
 150 }
 151
 152 int
 153 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
 154 {
 155
 156         PROC_ACTION(set_dbregs(td, dbregs));
 157 }
 158
 159 /*
 160  * Ptrace doesn't support fpregs at all, and there are no security holes
 161  * or translations for fpregs, so we can just copy them.
 162  */
 163 int
 164 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
 165 {
 166
 167         PROC_ACTION(fill_fpregs(td, fpregs));
 168 }
 169
 170 int
 171 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
 172 {
 173
 174         PROC_ACTION(set_fpregs(td, fpregs));
 175 }
 176
 177 #ifdef COMPAT_FREEBSD32
 178 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
 179 int
 180 proc_read_regs32(struct thread *td, struct reg32 *regs32)
 181 {
 182
 183         PROC_ACTION(fill_regs32(td, regs32));
 184 }
 185
 186 int
 187 proc_write_regs32(struct thread *td, struct reg32 *regs32)
 188 {
 189
 190         PROC_ACTION(set_regs32(td, regs32));
 191 }
 192
 193 int
 194 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 195 {
 196
 197         PROC_ACTION(fill_dbregs32(td, dbregs32));
 198 }
 199
 200 int
 201 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 202 {
 203
 204         PROC_ACTION(set_dbregs32(td, dbregs32));
 205 }
 206
 207 int
 208 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 209 {
 210
 211         PROC_ACTION(fill_fpregs32(td, fpregs32));
 212 }
 213
 214 int
 215 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 216 {
 217
 218         PROC_ACTION(set_fpregs32(td, fpregs32));
 219 }
 220 #endif
 221
 222 int
 223 proc_sstep(struct thread *td)
 224 {
 225
 226         PROC_ACTION(ptrace_single_step(td));
 227 }
 228
 229 int
 230 proc_rwmem(struct proc *p, struct uio *uio)
 231 {
 232         vm_map_t map;
 233         vm_offset_t pageno;             /* page number */
 234         vm_prot_t reqprot;
 235         int error, fault_flags, page_offset, writing;
 236
 237         /*
 238          * Assert that someone has locked this vmspace.  (Should be
 239          * curthread but we can't assert that.)  This keeps the process
 240          * from exiting out from under us until this operation completes.
 241          */
 242         PROC_ASSERT_HELD(p);
 243         PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 244
 245         /*
 246          * The map we want...
 247          */
 248         map = &p->p_vmspace->vm_map;
 249
 250         /*
 251          * If we are writing, then we request vm_fault() to create a private
 252          * copy of each page.  Since these copies will not be writeable by the
 253          * process, we must explicity request that they be dirtied.
 254          */
 255         writing = uio->uio_rw == UIO_WRITE;
 256         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 257         fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
 258
 259         /*
 260          * Only map in one page at a time.  We don't have to, but it
 261          * makes things easier.  This way is trivial - right?
 262          */
 263         do {
 264                 vm_offset_t uva;
 265                 u_int len;
 266                 vm_page_t m;
 267
 268                 uva = (vm_offset_t)uio->uio_offset;
 269
 270                 /*
 271                  * Get the page number of this segment.
 272                  */
 273                 pageno = trunc_page(uva);
 274                 page_offset = uva - pageno;
 275
 276                 /*
 277                  * How many bytes to copy
 278                  */
 279                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
 280
 281                 /*
 282                  * Fault and hold the page on behalf of the process.
 283                  */
 284                 error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
 285                 if (error != KERN_SUCCESS) {
 286                         if (error == KERN_RESOURCE_SHORTAGE)
 287                                 error = ENOMEM;
 288                         else
 289                                 error = EFAULT;
 290                         break;
 291                 }
 292
 293                 /*
 294                  * Now do the i/o move.
 295                  */
 296                 error = uiomove_fromphys(&m, page_offset, len, uio);
 297
 298                 /* Make the I-cache coherent for breakpoints. */
 299                 if (writing && error == 0) {
 300                         vm_map_lock_read(map);
 301                         if (vm_map_check_protection(map, pageno, pageno +
 302                             PAGE_SIZE, VM_PROT_EXECUTE))
 303                                 vm_sync_icache(map, uva, len);
 304                         vm_map_unlock_read(map);
 305                 }
 306
 307                 /*
 308                  * Release the page.
 309                  */
 310                 vm_page_lock(m);
 311                 vm_page_unhold(m);
 312                 vm_page_unlock(m);
 313
 314         } while (error == 0 && uio->uio_resid > 0);
 315
 316         return (error);
 317 }
 318
 319 static ssize_t
 320 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 321     size_t len, enum uio_rw rw)
 322 {
 323         struct iovec iov;
 324         struct uio uio;
 325         ssize_t slen;
 326         int error;
 327
 328         MPASS(len < SSIZE_MAX);
 329         slen = (ssize_t)len;
 330
 331         iov.iov_base = (caddr_t)buf;
 332         iov.iov_len = len;
 333         uio.uio_iov = &iov;
 334         uio.uio_iovcnt = 1;
 335         uio.uio_offset = va;
 336         uio.uio_resid = slen;
 337         uio.uio_segflg = UIO_SYSSPACE;
 338         uio.uio_rw = rw;
 339         uio.uio_td = td;
 340         error = proc_rwmem(p, &uio);
 341         if (uio.uio_resid == slen)
 342                 return (-1);
 343         return (slen - uio.uio_resid);
 344 }
 345
 346 ssize_t
 347 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 348     size_t len)
 349 {
 350
 351         return (proc_iop(td, p, va, buf, len, UIO_READ));
 352 }
 353
 354 ssize_t
 355 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 356     size_t len)
 357 {
 358
 359         return (proc_iop(td, p, va, buf, len, UIO_WRITE));
 360 }
 361
 362 static int
 363 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 364 {
 365         struct vattr vattr;
 366         vm_map_t map;
 367         vm_map_entry_t entry;
 368         vm_object_t obj, tobj, lobj;
 369         struct vmspace *vm;
 370         struct vnode *vp;
 371         char *freepath, *fullpath;
 372         u_int pathlen;
 373         int error, index;
 374
 375         error = 0;
 376         obj = NULL;
 377
 378         vm = vmspace_acquire_ref(p);
 379         map = &vm->vm_map;
 380         vm_map_lock_read(map);
 381
 382         do {
 383                 entry = map->header.next;
 384                 index = 0;
 385                 while (index < pve->pve_entry && entry != &map->header) {
 386                         entry = entry->next;
 387                         index++;
 388                 }
 389                 if (index != pve->pve_entry) {
 390                         error = EINVAL;
 391                         break;
 392                 }
 393                 while (entry != &map->header &&
 394                     (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
 395                         entry = entry->next;
 396                         index++;
 397                 }
 398                 if (entry == &map->header) {
 399                         error = ENOENT;
 400                         break;
 401                 }
 402
 403                 /* We got an entry. */
 404                 pve->pve_entry = index + 1;
 405                 pve->pve_timestamp = map->timestamp;
 406                 pve->pve_start = entry->start;
 407                 pve->pve_end = entry->end - 1;
 408                 pve->pve_offset = entry->offset;
 409                 pve->pve_prot = entry->protection;
 410
 411                 /* Backing object's path needed? */
 412                 if (pve->pve_pathlen == 0)
 413                         break;
 414
 415                 pathlen = pve->pve_pathlen;
 416                 pve->pve_pathlen = 0;
 417
 418                 obj = entry->object.vm_object;
 419                 if (obj != NULL)
 420                         VM_OBJECT_RLOCK(obj);
 421         } while (0);
 422
 423         vm_map_unlock_read(map);
 424
 425         pve->pve_fsid = VNOVAL;
 426         pve->pve_fileid = VNOVAL;
 427
 428         if (error == 0 && obj != NULL) {
 429                 lobj = obj;
 430                 for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
 431                         if (tobj != obj)
 432                                 VM_OBJECT_RLOCK(tobj);
 433                         if (lobj != obj)
 434                                 VM_OBJECT_RUNLOCK(lobj);
 435                         lobj = tobj;
 436                         pve->pve_offset += tobj->backing_object_offset;
 437                 }
 438                 vp = vm_object_vnode(lobj);
 439                 if (vp != NULL)
 440                         vref(vp);
 441                 if (lobj != obj)
 442                         VM_OBJECT_RUNLOCK(lobj);
 443                 VM_OBJECT_RUNLOCK(obj);
 444
 445                 if (vp != NULL) {
 446                         freepath = NULL;
 447                         fullpath = NULL;
 448                         vn_fullpath(td, vp, &fullpath, &freepath);
 449                         vn_lock(vp, LK_SHARED | LK_RETRY);
 450                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
 451                                 pve->pve_fileid = vattr.va_fileid;
 452                                 pve->pve_fsid = vattr.va_fsid;
 453                         }
 454                         vput(vp);
 455
 456                         if (fullpath != NULL) {
 457                                 pve->pve_pathlen = strlen(fullpath) + 1;
 458                                 if (pve->pve_pathlen <= pathlen) {
 459                                         error = copyout(fullpath, pve->pve_path,
 460                                             pve->pve_pathlen);
 461                                 } else
 462                                         error = ENAMETOOLONG;
 463                         }
 464                         if (freepath != NULL)
 465                                 free(freepath, M_TEMP);
 466                 }
 467         }
 468         vmspace_free(vm);
 469         if (error == 0)
 470                 CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
 471                     p->p_pid, pve->pve_entry, pve->pve_start);
 472
 473         return (error);
 474 }
 475
 476 #ifdef COMPAT_FREEBSD32
 477 static int
 478 ptrace_vm_entry32(struct thread *td, struct proc *p,
 479     struct ptrace_vm_entry32 *pve32)
 480 {
 481         struct ptrace_vm_entry pve;
 482         int error;
 483
 484         pve.pve_entry = pve32->pve_entry;
 485         pve.pve_pathlen = pve32->pve_pathlen;
 486         pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
 487
 488         error = ptrace_vm_entry(td, p, &pve);
 489         if (error == 0) {
 490                 pve32->pve_entry = pve.pve_entry;
 491                 pve32->pve_timestamp = pve.pve_timestamp;
 492                 pve32->pve_start = pve.pve_start;
 493                 pve32->pve_end = pve.pve_end;
 494                 pve32->pve_offset = pve.pve_offset;
 495                 pve32->pve_prot = pve.pve_prot;
 496                 pve32->pve_fileid = pve.pve_fileid;
 497                 pve32->pve_fsid = pve.pve_fsid;
 498         }
 499
 500         pve32->pve_pathlen = pve.pve_pathlen;
 501         return (error);
 502 }
 503
 504 static void
 505 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
 506     struct ptrace_lwpinfo32 *pl32)
 507 {
 508
 509         bzero(pl32, sizeof(*pl32));
 510         pl32->pl_lwpid = pl->pl_lwpid;
 511         pl32->pl_event = pl->pl_event;
 512         pl32->pl_flags = pl->pl_flags;
 513         pl32->pl_sigmask = pl->pl_sigmask;
 514         pl32->pl_siglist = pl->pl_siglist;
 515         siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
 516         strcpy(pl32->pl_tdname, pl->pl_tdname);
 517         pl32->pl_child_pid = pl->pl_child_pid;
 518         pl32->pl_syscall_code = pl->pl_syscall_code;
 519         pl32->pl_syscall_narg = pl->pl_syscall_narg;
 520 }
 521 #endif /* COMPAT_FREEBSD32 */
 522
 523 /*
 524  * Process debugging system call.
 525  */
 526 #ifndef _SYS_SYSPROTO_H_
 527 struct ptrace_args {
 528         int     req;
 529         pid_t   pid;
 530         caddr_t addr;
 531         int     data;
 532 };
 533 #endif
 534
 535 #ifdef COMPAT_FREEBSD32
 536 /*
 537  * This CPP subterfuge is to try and reduce the number of ifdefs in
 538  * the body of the code.
 539  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
 540  * becomes either:
 541  *   copyin(uap->addr, &r.reg, sizeof r.reg);
 542  * or
 543  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
 544  * .. except this is done at runtime.
 545  */
 546 #define COPYIN(u, k, s)         wrap32 ? \
 547         copyin(u, k ## 32, s ## 32) : \
 548         copyin(u, k, s)
 549 #define COPYOUT(k, u, s)        wrap32 ? \
 550         copyout(k ## 32, u, s ## 32) : \
 551         copyout(k, u, s)
 552 #else
 553 #define COPYIN(u, k, s)         copyin(u, k, s)
 554 #define COPYOUT(k, u, s)        copyout(k, u, s)
 555 #endif
 556 int
 557 sys_ptrace(struct thread *td, struct ptrace_args *uap)
 558 {
 559         /*
 560          * XXX this obfuscation is to reduce stack usage, but the register
 561          * structs may be too large to put on the stack anyway.
 562          */
 563         union {
 564                 struct ptrace_io_desc piod;
 565                 struct ptrace_lwpinfo pl;
 566                 struct ptrace_vm_entry pve;
 567                 struct dbreg dbreg;
 568                 struct fpreg fpreg;
 569                 struct reg reg;
 570 #ifdef COMPAT_FREEBSD32
 571                 struct dbreg32 dbreg32;
 572                 struct fpreg32 fpreg32;
 573                 struct reg32 reg32;
 574                 struct ptrace_io_desc32 piod32;
 575                 struct ptrace_lwpinfo32 pl32;
 576                 struct ptrace_vm_entry32 pve32;
 577 #endif
 578                 char args[nitems(td->td_sa.args) * sizeof(register_t)];
 579                 int ptevents;
 580         } r;
 581         void *addr;
 582         int error = 0;
 583 #ifdef COMPAT_FREEBSD32
 584         int wrap32 = 0;
 585
 586         if (SV_CURPROC_FLAG(SV_ILP32))
 587                 wrap32 = 1;
 588 #endif
 589         AUDIT_ARG_PID(uap->pid);
 590         AUDIT_ARG_CMD(uap->req);
 591         AUDIT_ARG_VALUE(uap->data);
 592         addr = &r;
 593         switch (uap->req) {
 594         case PT_GET_EVENT_MASK:
 595         case PT_GETREGS:
 596         case PT_GETFPREGS:
 597         case PT_GETDBREGS:
 598         case PT_LWPINFO:
 599         case PT_GET_SC_ARGS:
 600                 break;
 601         case PT_SETREGS:
 602                 error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
 603                 break;
 604         case PT_SETFPREGS:
 605                 error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
 606                 break;
 607         case PT_SETDBREGS:
 608                 error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
 609                 break;
 610         case PT_SET_EVENT_MASK:
 611                 if (uap->data != sizeof(r.ptevents))
 612                         error = EINVAL;
 613                 else
 614                         error = copyin(uap->addr, &r.ptevents, uap->data);
 615                 break;
 616         case PT_IO:
 617                 error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
 618                 break;
 619         case PT_VM_ENTRY:
 620                 error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
 621                 break;
 622         default:
 623                 addr = uap->addr;
 624                 break;
 625         }
 626         if (error)
 627                 return (error);
 628
 629         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
 630         if (error)
 631                 return (error);
 632
 633         switch (uap->req) {
 634         case PT_VM_ENTRY:
 635                 error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
 636                 break;
 637         case PT_IO:
 638                 error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
 639                 break;
 640         case PT_GETREGS:
 641                 error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
 642                 break;
 643         case PT_GETFPREGS:
 644                 error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
 645                 break;
 646         case PT_GETDBREGS:
 647                 error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
 648                 break;
 649         case PT_GET_EVENT_MASK:
 650                 /* NB: The size in uap->data is validated in kern_ptrace(). */
 651                 error = copyout(&r.ptevents, uap->addr, uap->data);
 652                 break;
 653         case PT_LWPINFO:
 654                 /* NB: The size in uap->data is validated in kern_ptrace(). */
 655                 error = copyout(&r.pl, uap->addr, uap->data);
 656                 break;
 657         case PT_GET_SC_ARGS:
 658                 error = copyout(r.args, uap->addr, MIN(uap->data,
 659                     sizeof(r.args)));
 660                 break;
 661         }
 662
 663         return (error);
 664 }
 665 #undef COPYIN
 666 #undef COPYOUT
 667
 668 #ifdef COMPAT_FREEBSD32
 669 /*
 670  *   PROC_READ(regs, td2, addr);
 671  * becomes either:
 672  *   proc_read_regs(td2, addr);
 673  * or
 674  *   proc_read_regs32(td2, addr);
 675  * .. except this is done at runtime.  There is an additional
 676  * complication in that PROC_WRITE disallows 32 bit consumers
 677  * from writing to 64 bit address space targets.
 678  */
 679 #define PROC_READ(w, t, a)      wrap32 ? \
 680         proc_read_ ## w ## 32(t, a) : \
 681         proc_read_ ## w (t, a)
 682 #define PROC_WRITE(w, t, a)     wrap32 ? \
 683         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
 684         proc_write_ ## w (t, a)
 685 #else
 686 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
 687 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
 688 #endif
 689
 690 void
 691 proc_set_traced(struct proc *p, bool stop)
 692 {
 693
 694         PROC_LOCK_ASSERT(p, MA_OWNED);
 695         p->p_flag |= P_TRACED;
 696         if (stop)
 697                 p->p_flag2 |= P2_PTRACE_FSTP;
 698         p->p_ptevents = PTRACE_DEFAULT;
 699         p->p_oppid = p->p_pptr->p_pid;
 700 }
 701
 702 int
 703 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 704 {
 705         struct iovec iov;
 706         struct uio uio;
 707         struct proc *curp, *p, *pp;
 708         struct thread *td2 = NULL, *td3;
 709         struct ptrace_io_desc *piod = NULL;
 710         struct ptrace_lwpinfo *pl;
 711         int error, num, tmp;
 712         int proctree_locked = 0;
 713         lwpid_t tid = 0, *buf;
 714 #ifdef COMPAT_FREEBSD32
 715         int wrap32 = 0, safe = 0;
 716         struct ptrace_io_desc32 *piod32 = NULL;
 717         struct ptrace_lwpinfo32 *pl32 = NULL;
 718         struct ptrace_lwpinfo plr;
 719 #endif
 720
 721         curp = td->td_proc;
 722
 723         /* Lock proctree before locking the process. */
 724         switch (req) {
 725         case PT_TRACE_ME:
 726         case PT_ATTACH:
 727         case PT_STEP:
 728         case PT_CONTINUE:
 729         case PT_TO_SCE:
 730         case PT_TO_SCX:
 731         case PT_SYSCALL:
 732         case PT_FOLLOW_FORK:
 733         case PT_LWP_EVENTS:
 734         case PT_GET_EVENT_MASK:
 735         case PT_SET_EVENT_MASK:
 736         case PT_DETACH:
 737         case PT_GET_SC_ARGS:
 738                 sx_xlock(&proctree_lock);
 739                 proctree_locked = 1;
 740                 break;
 741         default:
 742                 break;
 743         }
 744
 745         if (req == PT_TRACE_ME) {
 746                 p = td->td_proc;
 747                 PROC_LOCK(p);
 748         } else {
 749                 if (pid <= PID_MAX) {
 750                         if ((p = pfind(pid)) == NULL) {
 751                                 if (proctree_locked)
 752                                         sx_xunlock(&proctree_lock);
 753                                 return (ESRCH);
 754                         }
 755                 } else {
 756                         td2 = tdfind(pid, -1);
 757                         if (td2 == NULL) {
 758                                 if (proctree_locked)
 759                                         sx_xunlock(&proctree_lock);
 760                                 return (ESRCH);
 761                         }
 762                         p = td2->td_proc;
 763                         tid = pid;
 764                         pid = p->p_pid;
 765                 }
 766         }
 767         AUDIT_ARG_PROCESS(p);
 768
 769         if ((p->p_flag & P_WEXIT) != 0) {
 770                 error = ESRCH;
 771                 goto fail;
 772         }
 773         if ((error = p_cansee(td, p)) != 0)
 774                 goto fail;
 775
 776         if ((error = p_candebug(td, p)) != 0)
 777                 goto fail;
 778
 779         /*
 780          * System processes can't be debugged.
 781          */
 782         if ((p->p_flag & P_SYSTEM) != 0) {
 783                 error = EINVAL;
 784                 goto fail;
 785         }
 786
 787         if (tid == 0) {
 788                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
 789                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
 790                         td2 = p->p_xthread;
 791                 } else {
 792                         td2 = FIRST_THREAD_IN_PROC(p);
 793                 }
 794                 tid = td2->td_tid;
 795         }
 796
 797 #ifdef COMPAT_FREEBSD32
 798         /*
 799          * Test if we're a 32 bit client and what the target is.
 800          * Set the wrap controls accordingly.
 801          */
 802         if (SV_CURPROC_FLAG(SV_ILP32)) {
 803                 if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
 804                         safe = 1;
 805                 wrap32 = 1;
 806         }
 807 #endif
 808         /*
 809          * Permissions check
 810          */
 811         switch (req) {
 812         case PT_TRACE_ME:
 813                 /*
 814                  * Always legal, when there is a parent process which
 815                  * could trace us.  Otherwise, reject.
 816                  */
 817                 if ((p->p_flag & P_TRACED) != 0) {
 818                         error = EBUSY;
 819                         goto fail;
 820                 }
 821                 if (p->p_pptr == initproc) {
 822                         error = EPERM;
 823                         goto fail;
 824                 }
 825                 break;
 826
 827         case PT_ATTACH:
 828                 /* Self */
 829                 if (p == td->td_proc) {
 830                         error = EINVAL;
 831                         goto fail;
 832                 }
 833
 834                 /* Already traced */
 835                 if (p->p_flag & P_TRACED) {
 836                         error = EBUSY;
 837                         goto fail;
 838                 }
 839
 840                 /* Can't trace an ancestor if you're being traced. */
 841                 if (curp->p_flag & P_TRACED) {
 842                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
 843                                 if (pp == p) {
 844                                         error = EINVAL;
 845                                         goto fail;
 846                                 }
 847                         }
 848                 }
 849
 850
 851                 /* OK */
 852                 break;
 853
 854         case PT_CLEARSTEP:
 855                 /* Allow thread to clear single step for itself */
 856                 if (td->td_tid == tid)
 857                         break;
 858
 859                 /* FALLTHROUGH */
 860         default:
 861                 /* not being traced... */
 862                 if ((p->p_flag & P_TRACED) == 0) {
 863                         error = EPERM;
 864                         goto fail;
 865                 }
 866
 867                 /* not being traced by YOU */
 868                 if (p->p_pptr != td->td_proc) {
 869                         error = EBUSY;
 870                         goto fail;
 871                 }
 872
 873                 /* not currently stopped */
 874                 if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
 875                     p->p_suspcount != p->p_numthreads  ||
 876                     (p->p_flag & P_WAITED) == 0) {
 877                         error = EBUSY;
 878                         goto fail;
 879                 }
 880
 881                 /* OK */
 882                 break;
 883         }
 884
 885         /* Keep this process around until we finish this request. */
 886         _PHOLD(p);
 887
 888 #ifdef FIX_SSTEP
 889         /*
 890          * Single step fixup ala procfs
 891          */
 892         FIX_SSTEP(td2);
 893 #endif
 894
 895         /*
 896          * Actually do the requests
 897          */
 898
 899         td->td_retval[0] = 0;
 900
 901         switch (req) {
 902         case PT_TRACE_ME:
 903                 /* set my trace flag and "owner" so it can read/write me */
 904                 proc_set_traced(p, false);
 905                 if (p->p_flag & P_PPWAIT)
 906                         p->p_flag |= P_PPTRACE;
 907                 CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
 908                 break;
 909
 910         case PT_ATTACH:
 911                 /* security check done above */
 912                 /*
 913                  * It would be nice if the tracing relationship was separate
 914                  * from the parent relationship but that would require
 915                  * another set of links in the proc struct or for "wait"
 916                  * to scan the entire proc table.  To make life easier,
 917                  * we just re-parent the process we're trying to trace.
 918                  * The old parent is remembered so we can put things back
 919                  * on a "detach".
 920                  */
 921                 proc_set_traced(p, true);
 922                 if (p->p_pptr != td->td_proc) {
 923                         proc_reparent(p, td->td_proc);
 924                 }
 925                 CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
 926                     p->p_oppid);
 927
 928                 sx_xunlock(&proctree_lock);
 929                 proctree_locked = 0;
 930                 MPASS(p->p_xthread == NULL);
 931                 MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
 932
 933                 /*
 934                  * If already stopped due to a stop signal, clear the
 935                  * existing stop before triggering a traced SIGSTOP.
 936                  */
 937                 if ((p->p_flag & P_STOPPED_SIG) != 0) {
 938                         PROC_SLOCK(p);
 939                         p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
 940                         thread_unsuspend(p);
 941                         PROC_SUNLOCK(p);
 942                 }
 943
 944                 kern_psignal(p, SIGSTOP);
 945                 break;
 946
 947         case PT_CLEARSTEP:
 948                 CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
 949                     p->p_pid);
 950                 error = ptrace_clear_single_step(td2);
 951                 break;
 952
 953         case PT_SETSTEP:
 954                 CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
 955                     p->p_pid);
 956                 error = ptrace_single_step(td2);
 957                 break;
 958
 959         case PT_SUSPEND:
 960                 CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
 961                     p->p_pid);
 962                 td2->td_dbgflags |= TDB_SUSPEND;
 963                 thread_lock(td2);
 964                 td2->td_flags |= TDF_NEEDSUSPCHK;
 965                 thread_unlock(td2);
 966                 break;
 967
 968         case PT_RESUME:
 969                 CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
 970                     p->p_pid);
 971                 td2->td_dbgflags &= ~TDB_SUSPEND;
 972                 break;
 973
 974         case PT_FOLLOW_FORK:
 975                 CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
 976                     p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
 977                     data ? "enabled" : "disabled");
 978                 if (data)
 979                         p->p_ptevents |= PTRACE_FORK;
 980                 else
 981                         p->p_ptevents &= ~PTRACE_FORK;
 982                 break;
 983
 984         case PT_LWP_EVENTS:
 985                 CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
 986                     p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
 987                     data ? "enabled" : "disabled");
 988                 if (data)
 989                         p->p_ptevents |= PTRACE_LWP;
 990                 else
 991                         p->p_ptevents &= ~PTRACE_LWP;
 992                 break;
 993
 994         case PT_GET_EVENT_MASK:
 995                 if (data != sizeof(p->p_ptevents)) {
 996                         error = EINVAL;
 997                         break;
 998                 }
 999                 CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1000                     p->p_ptevents);
1001                 *(int *)addr = p->p_ptevents;
1002                 break;
1003
1004         case PT_SET_EVENT_MASK:
1005                 if (data != sizeof(p->p_ptevents)) {
1006                         error = EINVAL;
1007                         break;
1008                 }
1009                 tmp = *(int *)addr;
1010                 if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1011                     PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1012                         error = EINVAL;
1013                         break;
1014                 }
1015                 CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1016                     p->p_pid, p->p_ptevents, tmp);
1017                 p->p_ptevents = tmp;
1018                 break;
1019
1020         case PT_GET_SC_ARGS:
1021                 CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1022                 if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1023 #ifdef COMPAT_FREEBSD32
1024                     || (wrap32 && !safe)
1025 #endif
1026                     ) {
1027                         error = EINVAL;
1028                         break;
1029                 }
1030                 bzero(addr, sizeof(td2->td_sa.args));
1031 #ifdef COMPAT_FREEBSD32
1032                 if (wrap32)
1033                         for (num = 0; num < nitems(td2->td_sa.args); num++)
1034                                 ((uint32_t *)addr)[num] = (uint32_t)
1035                                     td2->td_sa.args[num];
1036                 else
1037 #endif
1038                         bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1039                             sizeof(register_t));
1040                 break;
1041
1042         case PT_STEP:
1043         case PT_CONTINUE:
1044         case PT_TO_SCE:
1045         case PT_TO_SCX:
1046         case PT_SYSCALL:
1047         case PT_DETACH:
1048                 /* Zero means do not send any signal */
1049                 if (data < 0 || data > _SIG_MAXSIG) {
1050                         error = EINVAL;
1051                         break;
1052                 }
1053
1054                 switch (req) {
1055                 case PT_STEP:
1056                         CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1057                             td2->td_tid, p->p_pid, data);
1058                         error = ptrace_single_step(td2);
1059                         if (error)
1060                                 goto out;
1061                         break;
1062                 case PT_CONTINUE:
1063                 case PT_TO_SCE:
1064                 case PT_TO_SCX:
1065                 case PT_SYSCALL:
1066                         if (addr != (void *)1) {
1067                                 error = ptrace_set_pc(td2,
1068                                     (u_long)(uintfptr_t)addr);
1069                                 if (error)
1070                                         goto out;
1071                         }
1072                         switch (req) {
1073                         case PT_TO_SCE:
1074                                 p->p_ptevents |= PTRACE_SCE;
1075                                 CTR4(KTR_PTRACE,
1076                     "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1077                                     p->p_pid, p->p_ptevents,
1078                                     (u_long)(uintfptr_t)addr, data);
1079                                 break;
1080                         case PT_TO_SCX:
1081                                 p->p_ptevents |= PTRACE_SCX;
1082                                 CTR4(KTR_PTRACE,
1083                     "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1084                                     p->p_pid, p->p_ptevents,
1085                                     (u_long)(uintfptr_t)addr, data);
1086                                 break;
1087                         case PT_SYSCALL:
1088                                 p->p_ptevents |= PTRACE_SYSCALL;
1089                                 CTR4(KTR_PTRACE,
1090                     "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1091                                     p->p_pid, p->p_ptevents,
1092                                     (u_long)(uintfptr_t)addr, data);
1093                                 break;
1094                         case PT_CONTINUE:
1095                                 CTR3(KTR_PTRACE,
1096                                     "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1097                                     p->p_pid, (u_long)(uintfptr_t)addr, data);
1098                                 break;
1099                         }
1100                         break;
1101                 case PT_DETACH:
1102                         /*
1103                          * Reset the process parent.
1104                          *
1105                          * NB: This clears P_TRACED before reparenting
1106                          * a detached process back to its original
1107                          * parent.  Otherwise the debugee will be set
1108                          * as an orphan of the debugger.
1109                          */
1110                         p->p_flag &= ~(P_TRACED | P_WAITED);
1111                         if (p->p_oppid != p->p_pptr->p_pid) {
1112                                 PROC_LOCK(p->p_pptr);
1113                                 sigqueue_take(p->p_ksi);
1114                                 PROC_UNLOCK(p->p_pptr);
1115
1116                                 pp = proc_realparent(p);
1117                                 proc_reparent(p, pp);
1118                                 if (pp == initproc)
1119                                         p->p_sigparent = SIGCHLD;
1120                                 CTR3(KTR_PTRACE,
1121                             "PT_DETACH: pid %d reparented to pid %d, sig %d",
1122                                     p->p_pid, pp->p_pid, data);
1123                         } else
1124                                 CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1125                                     p->p_pid, data);
1126                         p->p_oppid = 0;
1127                         p->p_ptevents = 0;
1128                         FOREACH_THREAD_IN_PROC(p, td3) {
1129                                 if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1130                                         sigqueue_delete(&td3->td_sigqueue,
1131                                             SIGSTOP);
1132                                 }
1133                                 td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1134                                     TDB_SUSPEND);
1135                         }
1136
1137                         if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1138                                 sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1139                                 p->p_flag2 &= ~P2_PTRACE_FSTP;
1140                         }
1141
1142                         /* should we send SIGCHLD? */
1143                         /* childproc_continued(p); */
1144                         break;
1145                 }
1146
1147                 sx_xunlock(&proctree_lock);
1148                 proctree_locked = 0;
1149
1150         sendsig:
1151                 MPASS(proctree_locked == 0);
1152
1153                 /*
1154                  * Clear the pending event for the thread that just
1155                  * reported its event (p_xthread).  This may not be
1156                  * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1157                  * the debugger is resuming a different thread.
1158                  *
1159                  * Deliver any pending signal via the reporting thread.
1160                  */
1161                 MPASS(p->p_xthread != NULL);
1162                 p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1163                 p->p_xthread->td_xsig = data;
1164                 p->p_xthread = NULL;
1165                 p->p_xsig = data;
1166
1167                 /*
1168                  * P_WKILLED is insurance that a PT_KILL/SIGKILL
1169                  * always works immediately, even if another thread is
1170                  * unsuspended first and attempts to handle a
1171                  * different signal or if the POSIX.1b style signal
1172                  * queue cannot accommodate any new signals.
1173                  */
1174                 if (data == SIGKILL)
1175                         p->p_flag |= P_WKILLED;
1176
1177                 /*
1178                  * Unsuspend all threads.  To leave a thread
1179                  * suspended, use PT_SUSPEND to suspend it before
1180                  * continuing the process.
1181                  */
1182                 PROC_SLOCK(p);
1183                 p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1184                 thread_unsuspend(p);
1185                 PROC_SUNLOCK(p);
1186                 break;
1187
1188         case PT_WRITE_I:
1189         case PT_WRITE_D:
1190                 td2->td_dbgflags |= TDB_USERWR;
1191                 PROC_UNLOCK(p);
1192                 error = 0;
1193                 if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1194                     sizeof(int)) != sizeof(int))
1195                         error = ENOMEM;
1196                 else
1197                         CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1198                             p->p_pid, addr, data);
1199                 PROC_LOCK(p);
1200                 break;
1201
1202         case PT_READ_I:
1203         case PT_READ_D:
1204                 PROC_UNLOCK(p);
1205                 error = tmp = 0;
1206                 if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1207                     sizeof(int)) != sizeof(int))
1208                         error = ENOMEM;
1209                 else
1210                         CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1211                             p->p_pid, addr, tmp);
1212                 td->td_retval[0] = tmp;
1213                 PROC_LOCK(p);
1214                 break;
1215
1216         case PT_IO:
1217 #ifdef COMPAT_FREEBSD32
1218                 if (wrap32) {
1219                         piod32 = addr;
1220                         iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1221                         iov.iov_len = piod32->piod_len;
1222                         uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1223                         uio.uio_resid = piod32->piod_len;
1224                 } else
1225 #endif
1226                 {
1227                         piod = addr;
1228                         iov.iov_base = piod->piod_addr;
1229                         iov.iov_len = piod->piod_len;
1230                         uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1231                         uio.uio_resid = piod->piod_len;
1232                 }
1233                 uio.uio_iov = &iov;
1234                 uio.uio_iovcnt = 1;
1235                 uio.uio_segflg = UIO_USERSPACE;
1236                 uio.uio_td = td;
1237 #ifdef COMPAT_FREEBSD32
1238                 tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1239 #else
1240                 tmp = piod->piod_op;
1241 #endif
1242                 switch (tmp) {
1243                 case PIOD_READ_D:
1244                 case PIOD_READ_I:
1245                         CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1246                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1247                         uio.uio_rw = UIO_READ;
1248                         break;
1249                 case PIOD_WRITE_D:
1250                 case PIOD_WRITE_I:
1251                         CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1252                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1253                         td2->td_dbgflags |= TDB_USERWR;
1254                         uio.uio_rw = UIO_WRITE;
1255                         break;
1256                 default:
1257                         error = EINVAL;
1258                         goto out;
1259                 }
1260                 PROC_UNLOCK(p);
1261                 error = proc_rwmem(p, &uio);
1262 #ifdef COMPAT_FREEBSD32
1263                 if (wrap32)
1264                         piod32->piod_len -= uio.uio_resid;
1265                 else
1266 #endif
1267                         piod->piod_len -= uio.uio_resid;
1268                 PROC_LOCK(p);
1269                 break;
1270
1271         case PT_KILL:
1272                 CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1273                 data = SIGKILL;
1274                 goto sendsig;   /* in PT_CONTINUE above */
1275
1276         case PT_SETREGS:
1277                 CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1278                     p->p_pid);
1279                 td2->td_dbgflags |= TDB_USERWR;
1280                 error = PROC_WRITE(regs, td2, addr);
1281                 break;
1282
1283         case PT_GETREGS:
1284                 CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1285                     p->p_pid);
1286                 error = PROC_READ(regs, td2, addr);
1287                 break;
1288
1289         case PT_SETFPREGS:
1290                 CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1291                     p->p_pid);
1292                 td2->td_dbgflags |= TDB_USERWR;
1293                 error = PROC_WRITE(fpregs, td2, addr);
1294                 break;
1295
1296         case PT_GETFPREGS:
1297                 CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1298                     p->p_pid);
1299                 error = PROC_READ(fpregs, td2, addr);
1300                 break;
1301
1302         case PT_SETDBREGS:
1303                 CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1304                     p->p_pid);
1305                 td2->td_dbgflags |= TDB_USERWR;
1306                 error = PROC_WRITE(dbregs, td2, addr);
1307                 break;
1308
1309         case PT_GETDBREGS:
1310                 CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1311                     p->p_pid);
1312                 error = PROC_READ(dbregs, td2, addr);
1313                 break;
1314
1315         case PT_LWPINFO:
1316                 if (data <= 0 ||
1317 #ifdef COMPAT_FREEBSD32
1318                     (!wrap32 && data > sizeof(*pl)) ||
1319                     (wrap32 && data > sizeof(*pl32))) {
1320 #else
1321                     data > sizeof(*pl)) {
1322 #endif
1323                         error = EINVAL;
1324                         break;
1325                 }
1326 #ifdef COMPAT_FREEBSD32
1327                 if (wrap32) {
1328                         pl = &plr;
1329                         pl32 = addr;
1330                 } else
1331 #endif
1332                 pl = addr;
1333                 bzero(pl, sizeof(*pl));
1334                 pl->pl_lwpid = td2->td_tid;
1335                 pl->pl_event = PL_EVENT_NONE;
1336                 pl->pl_flags = 0;
1337                 if (td2->td_dbgflags & TDB_XSIG) {
1338                         pl->pl_event = PL_EVENT_SIGNAL;
1339                         if (td2->td_si.si_signo != 0 &&
1340 #ifdef COMPAT_FREEBSD32
1341                             ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1342                             pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1343                             (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1344                             pl_siginfo) + sizeof(struct siginfo32)))
1345 #else
1346                             data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1347                             + sizeof(pl->pl_siginfo)
1348 #endif
1349                         ){
1350                                 pl->pl_flags |= PL_FLAG_SI;
1351                                 pl->pl_siginfo = td2->td_si;
1352                         }
1353                 }
1354                 if (td2->td_dbgflags & TDB_SCE)
1355                         pl->pl_flags |= PL_FLAG_SCE;
1356                 else if (td2->td_dbgflags & TDB_SCX)
1357                         pl->pl_flags |= PL_FLAG_SCX;
1358                 if (td2->td_dbgflags & TDB_EXEC)
1359                         pl->pl_flags |= PL_FLAG_EXEC;
1360                 if (td2->td_dbgflags & TDB_FORK) {
1361                         pl->pl_flags |= PL_FLAG_FORKED;
1362                         pl->pl_child_pid = td2->td_dbg_forked;
1363                         if (td2->td_dbgflags & TDB_VFORK)
1364                                 pl->pl_flags |= PL_FLAG_VFORKED;
1365                 } else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1366                     TDB_VFORK)
1367                         pl->pl_flags |= PL_FLAG_VFORK_DONE;
1368                 if (td2->td_dbgflags & TDB_CHILD)
1369                         pl->pl_flags |= PL_FLAG_CHILD;
1370                 if (td2->td_dbgflags & TDB_BORN)
1371                         pl->pl_flags |= PL_FLAG_BORN;
1372                 if (td2->td_dbgflags & TDB_EXIT)
1373                         pl->pl_flags |= PL_FLAG_EXITED;
1374                 pl->pl_sigmask = td2->td_sigmask;
1375                 pl->pl_siglist = td2->td_siglist;
1376                 strcpy(pl->pl_tdname, td2->td_name);
1377                 if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1378                         pl->pl_syscall_code = td2->td_sa.code;
1379                         pl->pl_syscall_narg = td2->td_sa.narg;
1380                 } else {
1381                         pl->pl_syscall_code = 0;
1382                         pl->pl_syscall_narg = 0;
1383                 }
1384 #ifdef COMPAT_FREEBSD32
1385                 if (wrap32)
1386                         ptrace_lwpinfo_to32(pl, pl32);
1387 #endif
1388                 CTR6(KTR_PTRACE,
1389     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1390                     td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1391                     pl->pl_child_pid, pl->pl_syscall_code);
1392                 break;
1393
1394         case PT_GETNUMLWPS:
1395                 CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1396                     p->p_numthreads);
1397                 td->td_retval[0] = p->p_numthreads;
1398                 break;
1399
1400         case PT_GETLWPLIST:
1401                 CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1402                     p->p_pid, data, p->p_numthreads);
1403                 if (data <= 0) {
1404                         error = EINVAL;
1405                         break;
1406                 }
1407                 num = imin(p->p_numthreads, data);
1408                 PROC_UNLOCK(p);
1409                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1410                 tmp = 0;
1411                 PROC_LOCK(p);
1412                 FOREACH_THREAD_IN_PROC(p, td2) {
1413                         if (tmp >= num)
1414                                 break;
1415                         buf[tmp++] = td2->td_tid;
1416                 }
1417                 PROC_UNLOCK(p);
1418                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1419                 free(buf, M_TEMP);
1420                 if (!error)
1421                         td->td_retval[0] = tmp;
1422                 PROC_LOCK(p);
1423                 break;
1424
1425         case PT_VM_TIMESTAMP:
1426                 CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1427                     p->p_pid, p->p_vmspace->vm_map.timestamp);
1428                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1429                 break;
1430
1431         case PT_VM_ENTRY:
1432                 PROC_UNLOCK(p);
1433 #ifdef COMPAT_FREEBSD32
1434                 if (wrap32)
1435                         error = ptrace_vm_entry32(td, p, addr);
1436                 else
1437 #endif
1438                 error = ptrace_vm_entry(td, p, addr);
1439                 PROC_LOCK(p);
1440                 break;
1441
1442         default:
1443 #ifdef __HAVE_PTRACE_MACHDEP
1444                 if (req >= PT_FIRSTMACH) {
1445                         PROC_UNLOCK(p);
1446                         error = cpu_ptrace(td2, req, addr, data);
1447                         PROC_LOCK(p);
1448                 } else
1449 #endif
1450                         /* Unknown request. */
1451                         error = EINVAL;
1452                 break;
1453         }
1454
1455 out:
1456         /* Drop our hold on this process now that the request has completed. */
1457         _PRELE(p);
1458 fail:
1459         PROC_UNLOCK(p);
1460         if (proctree_locked)
1461                 sx_xunlock(&proctree_lock);
1462         return (error);
1463 }
1464 #undef PROC_READ
1465 #undef PROC_WRITE
1466
1467 /*
1468  * Stop a process because of a debugging event;
1469  * stay stopped until p->p_step is cleared
1470  * (cleared by PIOCCONT in procfs).
1471  */
1472 void
1473 stopevent(struct proc *p, unsigned int event, unsigned int val)
1474 {
1475
1476         PROC_LOCK_ASSERT(p, MA_OWNED);
1477         p->p_step = 1;
1478         CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1479             val);
1480         do {
1481                 if (event != S_EXIT)
1482                         p->p_xsig = val;
1483                 p->p_xthread = NULL;
1484                 p->p_stype = event;     /* Which event caused the stop? */
1485                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
1486                 msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1487         } while (p->p_step);
1488 }