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 <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/ktr.h>
  40 #include <sys/limits.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/reg.h>
  44 #include <sys/syscallsubr.h>
  45 #include <sys/sysent.h>
  46 #include <sys/sysproto.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 #include <sys/caprights.h>
  56 #include <sys/filedesc.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 #endif
  72
  73 /* Assert it's safe to unlock a process, e.g. to allocate working memory */
  74 #define PROC_ASSERT_TRACEREQ(p) MPASS(((p)->p_flag2 & P2_PTRACEREQ) != 0)
  75
  76 /*
  77  * Functions implemented using PROC_ACTION():
  78  *
  79  * proc_read_regs(proc, regs)
  80  *      Get the current user-visible register set from the process
  81  *      and copy it into the regs structure (<machine/reg.h>).
  82  *      The process is stopped at the time read_regs is called.
  83  *
  84  * proc_write_regs(proc, regs)
  85  *      Update the current register set from the passed in regs
  86  *      structure.  Take care to avoid clobbering special CPU
  87  *      registers or privileged bits in the PSL.
  88  *      Depending on the architecture this may have fix-up work to do,
  89  *      especially if the IAR or PCW are modified.
  90  *      The process is stopped at the time write_regs is called.
  91  *
  92  * proc_read_fpregs, proc_write_fpregs
  93  *      deal with the floating point register set, otherwise as above.
  94  *
  95  * proc_read_dbregs, proc_write_dbregs
  96  *      deal with the processor debug register set, otherwise as above.
  97  *
  98  * proc_sstep(proc)
  99  *      Arrange for the process to trap after executing a single instruction.
 100  */
 101
 102 #define PROC_ACTION(action) do {                                        \
 103         int error;                                                      \
 104                                                                         \
 105         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
 106         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
 107                 error = EIO;                                            \
 108         else                                                            \
 109                 error = (action);                                       \
 110         return (error);                                                 \
 111 } while (0)
 112
 113 int
 114 proc_read_regs(struct thread *td, struct reg *regs)
 115 {
 116
 117         PROC_ACTION(fill_regs(td, regs));
 118 }
 119
 120 int
 121 proc_write_regs(struct thread *td, struct reg *regs)
 122 {
 123
 124         PROC_ACTION(set_regs(td, regs));
 125 }
 126
 127 int
 128 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
 129 {
 130
 131         PROC_ACTION(fill_dbregs(td, dbregs));
 132 }
 133
 134 int
 135 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
 136 {
 137
 138         PROC_ACTION(set_dbregs(td, dbregs));
 139 }
 140
 141 /*
 142  * Ptrace doesn't support fpregs at all, and there are no security holes
 143  * or translations for fpregs, so we can just copy them.
 144  */
 145 int
 146 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
 147 {
 148
 149         PROC_ACTION(fill_fpregs(td, fpregs));
 150 }
 151
 152 int
 153 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
 154 {
 155
 156         PROC_ACTION(set_fpregs(td, fpregs));
 157 }
 158
 159 static struct regset *
 160 proc_find_regset(struct thread *td, int note)
 161 {
 162         struct regset **regsetp, **regset_end, *regset;
 163         struct sysentvec *sv;
 164
 165         sv = td->td_proc->p_sysent;
 166         regsetp = sv->sv_regset_begin;
 167         if (regsetp == NULL)
 168                 return (NULL);
 169         regset_end = sv->sv_regset_end;
 170         MPASS(regset_end != NULL);
 171         for (; regsetp < regset_end; regsetp++) {
 172                 regset = *regsetp;
 173                 if (regset->note != note)
 174                         continue;
 175
 176                 return (regset);
 177         }
 178
 179         return (NULL);
 180 }
 181
 182 static int
 183 proc_read_regset(struct thread *td, int note, struct iovec *iov)
 184 {
 185         struct regset *regset;
 186         struct proc *p;
 187         void *buf;
 188         size_t size;
 189         int error;
 190
 191         regset = proc_find_regset(td, note);
 192         if (regset == NULL)
 193                 return (EINVAL);
 194
 195         if (iov->iov_base == NULL) {
 196                 iov->iov_len = regset->size;
 197                 if (iov->iov_len == 0)
 198                         return (EINVAL);
 199
 200                 return (0);
 201         }
 202
 203         /* The length is wrong, return an error */
 204         if (iov->iov_len != regset->size)
 205                 return (EINVAL);
 206
 207         if (regset->get == NULL)
 208                 return (EINVAL);
 209
 210         error = 0;
 211         size = regset->size;
 212         p = td->td_proc;
 213
 214         /* Drop the proc lock while allocating the temp buffer */
 215         PROC_ASSERT_TRACEREQ(p);
 216         PROC_UNLOCK(p);
 217         buf = malloc(size, M_TEMP, M_WAITOK);
 218         PROC_LOCK(p);
 219
 220         if (!regset->get(regset, td, buf, &size)) {
 221                 error = EINVAL;
 222         } else {
 223                 KASSERT(size == regset->size,
 224                     ("%s: Getter function changed the size", __func__));
 225
 226                 iov->iov_len = size;
 227                 PROC_UNLOCK(p);
 228                 error = copyout(buf, iov->iov_base, size);
 229                 PROC_LOCK(p);
 230         }
 231
 232         free(buf, M_TEMP);
 233
 234         return (error);
 235 }
 236
 237 static int
 238 proc_write_regset(struct thread *td, int note, struct iovec *iov)
 239 {
 240         struct regset *regset;
 241         struct proc *p;
 242         void *buf;
 243         size_t size;
 244         int error;
 245
 246         regset = proc_find_regset(td, note);
 247         if (regset == NULL)
 248                 return (EINVAL);
 249
 250         /* The length is wrong, return an error */
 251         if (iov->iov_len != regset->size)
 252                 return (EINVAL);
 253
 254         if (regset->set == NULL)
 255                 return (EINVAL);
 256
 257         size = regset->size;
 258         p = td->td_proc;
 259
 260         /* Drop the proc lock while allocating the temp buffer */
 261         PROC_ASSERT_TRACEREQ(p);
 262         PROC_UNLOCK(p);
 263         buf = malloc(size, M_TEMP, M_WAITOK);
 264         error = copyin(iov->iov_base, buf, size);
 265         PROC_LOCK(p);
 266
 267         if (error == 0) {
 268                 if (!regset->set(regset, td, buf, size)) {
 269                         error = EINVAL;
 270                 }
 271         }
 272
 273         free(buf, M_TEMP);
 274
 275         return (error);
 276 }
 277
 278 #ifdef COMPAT_FREEBSD32
 279 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
 280 int
 281 proc_read_regs32(struct thread *td, struct reg32 *regs32)
 282 {
 283
 284         PROC_ACTION(fill_regs32(td, regs32));
 285 }
 286
 287 int
 288 proc_write_regs32(struct thread *td, struct reg32 *regs32)
 289 {
 290
 291         PROC_ACTION(set_regs32(td, regs32));
 292 }
 293
 294 int
 295 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 296 {
 297
 298         PROC_ACTION(fill_dbregs32(td, dbregs32));
 299 }
 300
 301 int
 302 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 303 {
 304
 305         PROC_ACTION(set_dbregs32(td, dbregs32));
 306 }
 307
 308 int
 309 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 310 {
 311
 312         PROC_ACTION(fill_fpregs32(td, fpregs32));
 313 }
 314
 315 int
 316 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 317 {
 318
 319         PROC_ACTION(set_fpregs32(td, fpregs32));
 320 }
 321 #endif
 322
 323 int
 324 proc_sstep(struct thread *td)
 325 {
 326
 327         PROC_ACTION(ptrace_single_step(td));
 328 }
 329
 330 int
 331 proc_rwmem(struct proc *p, struct uio *uio)
 332 {
 333         vm_map_t map;
 334         vm_offset_t pageno;             /* page number */
 335         vm_prot_t reqprot;
 336         int error, fault_flags, page_offset, writing;
 337
 338         /*
 339          * Make sure that the process' vmspace remains live.
 340          */
 341         if (p != curproc)
 342                 PROC_ASSERT_HELD(p);
 343         PROC_LOCK_ASSERT(p, MA_NOTOWNED);
 344
 345         /*
 346          * The map we want...
 347          */
 348         map = &p->p_vmspace->vm_map;
 349
 350         /*
 351          * If we are writing, then we request vm_fault() to create a private
 352          * copy of each page.  Since these copies will not be writeable by the
 353          * process, we must explicity request that they be dirtied.
 354          */
 355         writing = uio->uio_rw == UIO_WRITE;
 356         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 357         fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
 358
 359         /*
 360          * Only map in one page at a time.  We don't have to, but it
 361          * makes things easier.  This way is trivial - right?
 362          */
 363         do {
 364                 vm_offset_t uva;
 365                 u_int len;
 366                 vm_page_t m;
 367
 368                 uva = (vm_offset_t)uio->uio_offset;
 369
 370                 /*
 371                  * Get the page number of this segment.
 372                  */
 373                 pageno = trunc_page(uva);
 374                 page_offset = uva - pageno;
 375
 376                 /*
 377                  * How many bytes to copy
 378                  */
 379                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
 380
 381                 /*
 382                  * Fault and hold the page on behalf of the process.
 383                  */
 384                 error = vm_fault(map, pageno, reqprot, fault_flags, &m);
 385                 if (error != KERN_SUCCESS) {
 386                         if (error == KERN_RESOURCE_SHORTAGE)
 387                                 error = ENOMEM;
 388                         else
 389                                 error = EFAULT;
 390                         break;
 391                 }
 392
 393                 /*
 394                  * Now do the i/o move.
 395                  */
 396                 error = uiomove_fromphys(&m, page_offset, len, uio);
 397
 398                 /* Make the I-cache coherent for breakpoints. */
 399                 if (writing && error == 0) {
 400                         vm_map_lock_read(map);
 401                         if (vm_map_check_protection(map, pageno, pageno +
 402                             PAGE_SIZE, VM_PROT_EXECUTE))
 403                                 vm_sync_icache(map, uva, len);
 404                         vm_map_unlock_read(map);
 405                 }
 406
 407                 /*
 408                  * Release the page.
 409                  */
 410                 vm_page_unwire(m, PQ_ACTIVE);
 411
 412         } while (error == 0 && uio->uio_resid > 0);
 413
 414         return (error);
 415 }
 416
 417 static ssize_t
 418 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 419     size_t len, enum uio_rw rw)
 420 {
 421         struct iovec iov;
 422         struct uio uio;
 423         ssize_t slen;
 424
 425         MPASS(len < SSIZE_MAX);
 426         slen = (ssize_t)len;
 427
 428         iov.iov_base = (caddr_t)buf;
 429         iov.iov_len = len;
 430         uio.uio_iov = &iov;
 431         uio.uio_iovcnt = 1;
 432         uio.uio_offset = va;
 433         uio.uio_resid = slen;
 434         uio.uio_segflg = UIO_SYSSPACE;
 435         uio.uio_rw = rw;
 436         uio.uio_td = td;
 437         proc_rwmem(p, &uio);
 438         if (uio.uio_resid == slen)
 439                 return (-1);
 440         return (slen - uio.uio_resid);
 441 }
 442
 443 ssize_t
 444 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 445     size_t len)
 446 {
 447
 448         return (proc_iop(td, p, va, buf, len, UIO_READ));
 449 }
 450
 451 ssize_t
 452 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
 453     size_t len)
 454 {
 455
 456         return (proc_iop(td, p, va, buf, len, UIO_WRITE));
 457 }
 458
 459 static int
 460 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 461 {
 462         struct vattr vattr;
 463         vm_map_t map;
 464         vm_map_entry_t entry;
 465         vm_object_t obj, tobj, lobj;
 466         struct vmspace *vm;
 467         struct vnode *vp;
 468         char *freepath, *fullpath;
 469         u_int pathlen;
 470         int error, index;
 471
 472         error = 0;
 473         obj = NULL;
 474
 475         vm = vmspace_acquire_ref(p);
 476         map = &vm->vm_map;
 477         vm_map_lock_read(map);
 478
 479         do {
 480                 KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
 481                     ("Submap in map header"));
 482                 index = 0;
 483                 VM_MAP_ENTRY_FOREACH(entry, map) {
 484                         if (index >= pve->pve_entry &&
 485                             (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
 486                                 break;
 487                         index++;
 488                 }
 489                 if (index < pve->pve_entry) {
 490                         error = EINVAL;
 491                         break;
 492                 }
 493                 if (entry == &map->header) {
 494                         error = ENOENT;
 495                         break;
 496                 }
 497
 498                 /* We got an entry. */
 499                 pve->pve_entry = index + 1;
 500                 pve->pve_timestamp = map->timestamp;
 501                 pve->pve_start = entry->start;
 502                 pve->pve_end = entry->end - 1;
 503                 pve->pve_offset = entry->offset;
 504                 pve->pve_prot = entry->protection;
 505
 506                 /* Backing object's path needed? */
 507                 if (pve->pve_pathlen == 0)
 508                         break;
 509
 510                 pathlen = pve->pve_pathlen;
 511                 pve->pve_pathlen = 0;
 512
 513                 obj = entry->object.vm_object;
 514                 if (obj != NULL)
 515                         VM_OBJECT_RLOCK(obj);
 516         } while (0);
 517
 518         vm_map_unlock_read(map);
 519
 520         pve->pve_fsid = VNOVAL;
 521         pve->pve_fileid = VNOVAL;
 522
 523         if (error == 0 && obj != NULL) {
 524                 lobj = obj;
 525                 for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
 526                         if (tobj != obj)
 527                                 VM_OBJECT_RLOCK(tobj);
 528                         if (lobj != obj)
 529                                 VM_OBJECT_RUNLOCK(lobj);
 530                         lobj = tobj;
 531                         pve->pve_offset += tobj->backing_object_offset;
 532                 }
 533                 vp = vm_object_vnode(lobj);
 534                 if (vp != NULL)
 535                         vref(vp);
 536                 if (lobj != obj)
 537                         VM_OBJECT_RUNLOCK(lobj);
 538                 VM_OBJECT_RUNLOCK(obj);
 539
 540                 if (vp != NULL) {
 541                         freepath = NULL;
 542                         fullpath = NULL;
 543                         vn_fullpath(vp, &fullpath, &freepath);
 544                         vn_lock(vp, LK_SHARED | LK_RETRY);
 545                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
 546                                 pve->pve_fileid = vattr.va_fileid;
 547                                 pve->pve_fsid = vattr.va_fsid;
 548                         }
 549                         vput(vp);
 550
 551                         if (fullpath != NULL) {
 552                                 pve->pve_pathlen = strlen(fullpath) + 1;
 553                                 if (pve->pve_pathlen <= pathlen) {
 554                                         error = copyout(fullpath, pve->pve_path,
 555                                             pve->pve_pathlen);
 556                                 } else
 557                                         error = ENAMETOOLONG;
 558                         }
 559                         if (freepath != NULL)
 560                                 free(freepath, M_TEMP);
 561                 }
 562         }
 563         vmspace_free(vm);
 564         if (error == 0)
 565                 CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
 566                     p->p_pid, pve->pve_entry, pve->pve_start);
 567
 568         return (error);
 569 }
 570
 571 /*
 572  * Process debugging system call.
 573  */
 574 #ifndef _SYS_SYSPROTO_H_
 575 struct ptrace_args {
 576         int     req;
 577         pid_t   pid;
 578         caddr_t addr;
 579         int     data;
 580 };
 581 #endif
 582
 583 int
 584 sys_ptrace(struct thread *td, struct ptrace_args *uap)
 585 {
 586         /*
 587          * XXX this obfuscation is to reduce stack usage, but the register
 588          * structs may be too large to put on the stack anyway.
 589          */
 590         union {
 591                 struct ptrace_io_desc piod;
 592                 struct ptrace_lwpinfo pl;
 593                 struct ptrace_vm_entry pve;
 594                 struct ptrace_coredump pc;
 595                 struct dbreg dbreg;
 596                 struct fpreg fpreg;
 597                 struct reg reg;
 598                 struct iovec vec;
 599                 syscallarg_t args[nitems(td->td_sa.args)];
 600                 struct ptrace_sc_ret psr;
 601                 int ptevents;
 602         } r;
 603         void *addr;
 604         int error;
 605
 606         if (!allow_ptrace)
 607                 return (ENOSYS);
 608         error = 0;
 609
 610         AUDIT_ARG_PID(uap->pid);
 611         AUDIT_ARG_CMD(uap->req);
 612         AUDIT_ARG_VALUE(uap->data);
 613         addr = &r;
 614         switch (uap->req) {
 615         case PT_GET_EVENT_MASK:
 616         case PT_LWPINFO:
 617         case PT_GET_SC_ARGS:
 618         case PT_GET_SC_RET:
 619                 break;
 620         case PT_GETREGS:
 621                 bzero(&r.reg, sizeof(r.reg));
 622                 break;
 623         case PT_GETFPREGS:
 624                 bzero(&r.fpreg, sizeof(r.fpreg));
 625                 break;
 626         case PT_GETDBREGS:
 627                 bzero(&r.dbreg, sizeof(r.dbreg));
 628                 break;
 629         case PT_GETREGSET:
 630         case PT_SETREGSET:
 631                 error = copyin(uap->addr, &r.vec, sizeof(r.vec));
 632                 break;
 633         case PT_SETREGS:
 634                 error = copyin(uap->addr, &r.reg, sizeof(r.reg));
 635                 break;
 636         case PT_SETFPREGS:
 637                 error = copyin(uap->addr, &r.fpreg, sizeof(r.fpreg));
 638                 break;
 639         case PT_SETDBREGS:
 640                 error = copyin(uap->addr, &r.dbreg, sizeof(r.dbreg));
 641                 break;
 642         case PT_SET_EVENT_MASK:
 643                 if (uap->data != sizeof(r.ptevents))
 644                         error = EINVAL;
 645                 else
 646                         error = copyin(uap->addr, &r.ptevents, uap->data);
 647                 break;
 648         case PT_IO:
 649                 error = copyin(uap->addr, &r.piod, sizeof(r.piod));
 650                 break;
 651         case PT_VM_ENTRY:
 652                 error = copyin(uap->addr, &r.pve, sizeof(r.pve));
 653                 break;
 654         case PT_COREDUMP:
 655                 if (uap->data != sizeof(r.pc))
 656                         error = EINVAL;
 657                 else
 658                         error = copyin(uap->addr, &r.pc, uap->data);
 659                 break;
 660         default:
 661                 addr = uap->addr;
 662                 break;
 663         }
 664         if (error)
 665                 return (error);
 666
 667         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
 668         if (error)
 669                 return (error);
 670
 671         switch (uap->req) {
 672         case PT_VM_ENTRY:
 673                 error = copyout(&r.pve, uap->addr, sizeof(r.pve));
 674                 break;
 675         case PT_IO:
 676                 error = copyout(&r.piod, uap->addr, sizeof(r.piod));
 677                 break;
 678         case PT_GETREGS:
 679                 error = copyout(&r.reg, uap->addr, sizeof(r.reg));
 680                 break;
 681         case PT_GETFPREGS:
 682                 error = copyout(&r.fpreg, uap->addr, sizeof(r.fpreg));
 683                 break;
 684         case PT_GETDBREGS:
 685                 error = copyout(&r.dbreg, uap->addr, sizeof(r.dbreg));
 686                 break;
 687         case PT_GETREGSET:
 688                 error = copyout(&r.vec, uap->addr, sizeof(r.vec));
 689                 break;
 690         case PT_GET_EVENT_MASK:
 691                 /* NB: The size in uap->data is validated in kern_ptrace(). */
 692                 error = copyout(&r.ptevents, uap->addr, uap->data);
 693                 break;
 694         case PT_LWPINFO:
 695                 /* NB: The size in uap->data is validated in kern_ptrace(). */
 696                 error = copyout(&r.pl, uap->addr, uap->data);
 697                 break;
 698         case PT_GET_SC_ARGS:
 699                 error = copyout(r.args, uap->addr, MIN(uap->data,
 700                     sizeof(r.args)));
 701                 break;
 702         case PT_GET_SC_RET:
 703                 error = copyout(&r.psr, uap->addr, MIN(uap->data,
 704                     sizeof(r.psr)));
 705                 break;
 706         }
 707
 708         return (error);
 709 }
 710
 711 #ifdef COMPAT_FREEBSD32
 712 /*
 713  *   PROC_READ(regs, td2, addr);
 714  * becomes either:
 715  *   proc_read_regs(td2, addr);
 716  * or
 717  *   proc_read_regs32(td2, addr);
 718  * .. except this is done at runtime.  There is an additional
 719  * complication in that PROC_WRITE disallows 32 bit consumers
 720  * from writing to 64 bit address space targets.
 721  */
 722 #define PROC_READ(w, t, a)      wrap32 ? \
 723         proc_read_ ## w ## 32(t, a) : \
 724         proc_read_ ## w (t, a)
 725 #define PROC_WRITE(w, t, a)     wrap32 ? \
 726         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
 727         proc_write_ ## w (t, a)
 728 #else
 729 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
 730 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
 731 #endif
 732
 733 void
 734 proc_set_traced(struct proc *p, bool stop)
 735 {
 736
 737         sx_assert(&proctree_lock, SX_XLOCKED);
 738         PROC_LOCK_ASSERT(p, MA_OWNED);
 739         p->p_flag |= P_TRACED;
 740         if (stop)
 741                 p->p_flag2 |= P2_PTRACE_FSTP;
 742         p->p_ptevents = PTRACE_DEFAULT;
 743 }
 744
 745 void
 746 ptrace_unsuspend(struct proc *p)
 747 {
 748         PROC_LOCK_ASSERT(p, MA_OWNED);
 749
 750         PROC_SLOCK(p);
 751         p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
 752         thread_unsuspend(p);
 753         PROC_SUNLOCK(p);
 754         itimer_proc_continue(p);
 755         kqtimer_proc_continue(p);
 756 }
 757
 758 static int
 759 proc_can_ptrace(struct thread *td, struct proc *p)
 760 {
 761         int error;
 762
 763         PROC_LOCK_ASSERT(p, MA_OWNED);
 764
 765         if ((p->p_flag & P_WEXIT) != 0)
 766                 return (ESRCH);
 767
 768         if ((error = p_cansee(td, p)) != 0)
 769                 return (error);
 770         if ((error = p_candebug(td, p)) != 0)
 771                 return (error);
 772
 773         /* not being traced... */
 774         if ((p->p_flag & P_TRACED) == 0)
 775                 return (EPERM);
 776
 777         /* not being traced by YOU */
 778         if (p->p_pptr != td->td_proc)
 779                 return (EBUSY);
 780
 781         /* not currently stopped */
 782         if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
 783             p->p_suspcount != p->p_numthreads  ||
 784             (p->p_flag & P_WAITED) == 0)
 785                 return (EBUSY);
 786
 787         return (0);
 788 }
 789
 790 static struct thread *
 791 ptrace_sel_coredump_thread(struct proc *p)
 792 {
 793         struct thread *td2;
 794
 795         PROC_LOCK_ASSERT(p, MA_OWNED);
 796         MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
 797
 798         FOREACH_THREAD_IN_PROC(p, td2) {
 799                 if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
 800                         return (td2);
 801         }
 802         return (NULL);
 803 }
 804
 805 int
 806 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 807 {
 808         struct iovec iov;
 809         struct uio uio;
 810         struct proc *curp, *p, *pp;
 811         struct thread *td2 = NULL, *td3;
 812         struct ptrace_io_desc *piod = NULL;
 813         struct ptrace_lwpinfo *pl;
 814         struct ptrace_sc_ret *psr;
 815         struct file *fp;
 816         struct ptrace_coredump *pc;
 817         struct thr_coredump_req *tcq;
 818         int error, num, tmp;
 819         lwpid_t tid = 0, *buf;
 820 #ifdef COMPAT_FREEBSD32
 821         int wrap32 = 0, safe = 0;
 822 #endif
 823         bool proctree_locked, p2_req_set;
 824
 825         curp = td->td_proc;
 826         proctree_locked = false;
 827         p2_req_set = false;
 828
 829         /* Lock proctree before locking the process. */
 830         switch (req) {
 831         case PT_TRACE_ME:
 832         case PT_ATTACH:
 833         case PT_STEP:
 834         case PT_CONTINUE:
 835         case PT_TO_SCE:
 836         case PT_TO_SCX:
 837         case PT_SYSCALL:
 838         case PT_FOLLOW_FORK:
 839         case PT_LWP_EVENTS:
 840         case PT_GET_EVENT_MASK:
 841         case PT_SET_EVENT_MASK:
 842         case PT_DETACH:
 843         case PT_GET_SC_ARGS:
 844                 sx_xlock(&proctree_lock);
 845                 proctree_locked = true;
 846                 break;
 847         default:
 848                 break;
 849         }
 850
 851         if (req == PT_TRACE_ME) {
 852                 p = td->td_proc;
 853                 PROC_LOCK(p);
 854         } else {
 855                 if (pid <= PID_MAX) {
 856                         if ((p = pfind(pid)) == NULL) {
 857                                 if (proctree_locked)
 858                                         sx_xunlock(&proctree_lock);
 859                                 return (ESRCH);
 860                         }
 861                 } else {
 862                         td2 = tdfind(pid, -1);
 863                         if (td2 == NULL) {
 864                                 if (proctree_locked)
 865                                         sx_xunlock(&proctree_lock);
 866                                 return (ESRCH);
 867                         }
 868                         p = td2->td_proc;
 869                         tid = pid;
 870                         pid = p->p_pid;
 871                 }
 872         }
 873         AUDIT_ARG_PROCESS(p);
 874
 875         if ((p->p_flag & P_WEXIT) != 0) {
 876                 error = ESRCH;
 877                 goto fail;
 878         }
 879         if ((error = p_cansee(td, p)) != 0)
 880                 goto fail;
 881
 882         if ((error = p_candebug(td, p)) != 0)
 883                 goto fail;
 884
 885         /*
 886          * System processes can't be debugged.
 887          */
 888         if ((p->p_flag & P_SYSTEM) != 0) {
 889                 error = EINVAL;
 890                 goto fail;
 891         }
 892
 893         if (tid == 0) {
 894                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
 895                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
 896                         td2 = p->p_xthread;
 897                 } else {
 898                         td2 = FIRST_THREAD_IN_PROC(p);
 899                 }
 900                 tid = td2->td_tid;
 901         }
 902
 903 #ifdef COMPAT_FREEBSD32
 904         /*
 905          * Test if we're a 32 bit client and what the target is.
 906          * Set the wrap controls accordingly.
 907          */
 908         if (SV_CURPROC_FLAG(SV_ILP32)) {
 909                 if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
 910                         safe = 1;
 911                 wrap32 = 1;
 912         }
 913 #endif
 914         /*
 915          * Permissions check
 916          */
 917         switch (req) {
 918         case PT_TRACE_ME:
 919                 /*
 920                  * Always legal, when there is a parent process which
 921                  * could trace us.  Otherwise, reject.
 922                  */
 923                 if ((p->p_flag & P_TRACED) != 0) {
 924                         error = EBUSY;
 925                         goto fail;
 926                 }
 927                 if (p->p_pptr == initproc) {
 928                         error = EPERM;
 929                         goto fail;
 930                 }
 931                 break;
 932
 933         case PT_ATTACH:
 934                 /* Self */
 935                 if (p == td->td_proc) {
 936                         error = EINVAL;
 937                         goto fail;
 938                 }
 939
 940                 /* Already traced */
 941                 if (p->p_flag & P_TRACED) {
 942                         error = EBUSY;
 943                         goto fail;
 944                 }
 945
 946                 /* Can't trace an ancestor if you're being traced. */
 947                 if (curp->p_flag & P_TRACED) {
 948                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
 949                                 if (pp == p) {
 950                                         error = EINVAL;
 951                                         goto fail;
 952                                 }
 953                         }
 954                 }
 955
 956                 /* OK */
 957                 break;
 958
 959         case PT_CLEARSTEP:
 960                 /* Allow thread to clear single step for itself */
 961                 if (td->td_tid == tid)
 962                         break;
 963
 964                 /* FALLTHROUGH */
 965         default:
 966                 /*
 967                  * Check for ptrace eligibility before waiting for
 968                  * holds to drain.
 969                  */
 970                 error = proc_can_ptrace(td, p);
 971                 if (error != 0)
 972                         goto fail;
 973
 974                 /*
 975                  * Block parallel ptrace requests.  Most important, do
 976                  * not allow other thread in debugger to continue the
 977                  * debuggee until coredump finished.
 978                  */
 979                 while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
 980                         if (proctree_locked)
 981                                 sx_xunlock(&proctree_lock);
 982                         error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
 983                             (proctree_locked ? PDROP : 0), "pptrace", 0);
 984                         if (proctree_locked) {
 985                                 sx_xlock(&proctree_lock);
 986                                 PROC_LOCK(p);
 987                         }
 988                         if (error == 0 && td2->td_proc != p)
 989                                 error = ESRCH;
 990                         if (error == 0)
 991                                 error = proc_can_ptrace(td, p);
 992                         if (error != 0)
 993                                 goto fail;
 994                 }
 995
 996                 /* Ok */
 997                 break;
 998         }
 999
1000         /*
1001          * Keep this process around and request parallel ptrace()
1002          * request to wait until we finish this request.
1003          */
1004         MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
1005         p->p_flag2 |= P2_PTRACEREQ;
1006         p2_req_set = true;
1007         _PHOLD(p);
1008
1009         /*
1010          * Actually do the requests
1011          */
1012
1013         td->td_retval[0] = 0;
1014
1015         switch (req) {
1016         case PT_TRACE_ME:
1017                 /* set my trace flag and "owner" so it can read/write me */
1018                 proc_set_traced(p, false);
1019                 if (p->p_flag & P_PPWAIT)
1020                         p->p_flag |= P_PPTRACE;
1021                 CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
1022                 break;
1023
1024         case PT_ATTACH:
1025                 /* security check done above */
1026                 /*
1027                  * It would be nice if the tracing relationship was separate
1028                  * from the parent relationship but that would require
1029                  * another set of links in the proc struct or for "wait"
1030                  * to scan the entire proc table.  To make life easier,
1031                  * we just re-parent the process we're trying to trace.
1032                  * The old parent is remembered so we can put things back
1033                  * on a "detach".
1034                  */
1035                 proc_set_traced(p, true);
1036                 proc_reparent(p, td->td_proc, false);
1037                 CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
1038                     p->p_oppid);
1039
1040                 sx_xunlock(&proctree_lock);
1041                 proctree_locked = false;
1042                 MPASS(p->p_xthread == NULL);
1043                 MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
1044
1045                 /*
1046                  * If already stopped due to a stop signal, clear the
1047                  * existing stop before triggering a traced SIGSTOP.
1048                  */
1049                 if ((p->p_flag & P_STOPPED_SIG) != 0) {
1050                         PROC_SLOCK(p);
1051                         p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
1052                         thread_unsuspend(p);
1053                         PROC_SUNLOCK(p);
1054                 }
1055
1056                 kern_psignal(p, SIGSTOP);
1057                 break;
1058
1059         case PT_CLEARSTEP:
1060                 CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
1061                     p->p_pid);
1062                 error = ptrace_clear_single_step(td2);
1063                 break;
1064
1065         case PT_SETSTEP:
1066                 CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
1067                     p->p_pid);
1068                 error = ptrace_single_step(td2);
1069                 break;
1070
1071         case PT_SUSPEND:
1072                 CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
1073                     p->p_pid);
1074                 td2->td_dbgflags |= TDB_SUSPEND;
1075                 thread_lock(td2);
1076                 td2->td_flags |= TDF_NEEDSUSPCHK;
1077                 thread_unlock(td2);
1078                 break;
1079
1080         case PT_RESUME:
1081                 CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
1082                     p->p_pid);
1083                 td2->td_dbgflags &= ~TDB_SUSPEND;
1084                 break;
1085
1086         case PT_FOLLOW_FORK:
1087                 CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
1088                     p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
1089                     data ? "enabled" : "disabled");
1090                 if (data)
1091                         p->p_ptevents |= PTRACE_FORK;
1092                 else
1093                         p->p_ptevents &= ~PTRACE_FORK;
1094                 break;
1095
1096         case PT_LWP_EVENTS:
1097                 CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
1098                     p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
1099                     data ? "enabled" : "disabled");
1100                 if (data)
1101                         p->p_ptevents |= PTRACE_LWP;
1102                 else
1103                         p->p_ptevents &= ~PTRACE_LWP;
1104                 break;
1105
1106         case PT_GET_EVENT_MASK:
1107                 if (data != sizeof(p->p_ptevents)) {
1108                         error = EINVAL;
1109                         break;
1110                 }
1111                 CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1112                     p->p_ptevents);
1113                 *(int *)addr = p->p_ptevents;
1114                 break;
1115
1116         case PT_SET_EVENT_MASK:
1117                 if (data != sizeof(p->p_ptevents)) {
1118                         error = EINVAL;
1119                         break;
1120                 }
1121                 tmp = *(int *)addr;
1122                 if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1123                     PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1124                         error = EINVAL;
1125                         break;
1126                 }
1127                 CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1128                     p->p_pid, p->p_ptevents, tmp);
1129                 p->p_ptevents = tmp;
1130                 break;
1131
1132         case PT_GET_SC_ARGS:
1133                 CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1134                 if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1135 #ifdef COMPAT_FREEBSD32
1136                     || (wrap32 && !safe)
1137 #endif
1138                     ) {
1139                         error = EINVAL;
1140                         break;
1141                 }
1142                 bzero(addr, sizeof(td2->td_sa.args));
1143                 /* See the explanation in linux_ptrace_get_syscall_info(). */
1144                 bcopy(td2->td_sa.args, addr, SV_PROC_ABI(td->td_proc) ==
1145                     SV_ABI_LINUX ? sizeof(td2->td_sa.args) :
1146                     td2->td_sa.callp->sy_narg * sizeof(syscallarg_t));
1147                 break;
1148
1149         case PT_GET_SC_RET:
1150                 if ((td2->td_dbgflags & (TDB_SCX)) == 0
1151 #ifdef COMPAT_FREEBSD32
1152                     || (wrap32 && !safe)
1153 #endif
1154                     ) {
1155                         error = EINVAL;
1156                         break;
1157                 }
1158                 psr = addr;
1159                 bzero(psr, sizeof(*psr));
1160                 psr->sr_error = td2->td_errno;
1161                 if (psr->sr_error == 0) {
1162                         psr->sr_retval[0] = td2->td_retval[0];
1163                         psr->sr_retval[1] = td2->td_retval[1];
1164                 }
1165                 CTR4(KTR_PTRACE,
1166                     "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1167                     p->p_pid, psr->sr_error, psr->sr_retval[0],
1168                     psr->sr_retval[1]);
1169                 break;
1170
1171         case PT_STEP:
1172         case PT_CONTINUE:
1173         case PT_TO_SCE:
1174         case PT_TO_SCX:
1175         case PT_SYSCALL:
1176         case PT_DETACH:
1177                 /* Zero means do not send any signal */
1178                 if (data < 0 || data > _SIG_MAXSIG) {
1179                         error = EINVAL;
1180                         break;
1181                 }
1182
1183                 switch (req) {
1184                 case PT_STEP:
1185                         CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1186                             td2->td_tid, p->p_pid, data);
1187                         error = ptrace_single_step(td2);
1188                         if (error)
1189                                 goto out;
1190                         break;
1191                 case PT_CONTINUE:
1192                 case PT_TO_SCE:
1193                 case PT_TO_SCX:
1194                 case PT_SYSCALL:
1195                         if (addr != (void *)1) {
1196                                 error = ptrace_set_pc(td2,
1197                                     (u_long)(uintfptr_t)addr);
1198                                 if (error)
1199                                         goto out;
1200                         }
1201                         switch (req) {
1202                         case PT_TO_SCE:
1203                                 p->p_ptevents |= PTRACE_SCE;
1204                                 CTR4(KTR_PTRACE,
1205                     "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1206                                     p->p_pid, p->p_ptevents,
1207                                     (u_long)(uintfptr_t)addr, data);
1208                                 break;
1209                         case PT_TO_SCX:
1210                                 p->p_ptevents |= PTRACE_SCX;
1211                                 CTR4(KTR_PTRACE,
1212                     "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1213                                     p->p_pid, p->p_ptevents,
1214                                     (u_long)(uintfptr_t)addr, data);
1215                                 break;
1216                         case PT_SYSCALL:
1217                                 p->p_ptevents |= PTRACE_SYSCALL;
1218                                 CTR4(KTR_PTRACE,
1219                     "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1220                                     p->p_pid, p->p_ptevents,
1221                                     (u_long)(uintfptr_t)addr, data);
1222                                 break;
1223                         case PT_CONTINUE:
1224                                 CTR3(KTR_PTRACE,
1225                                     "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1226                                     p->p_pid, (u_long)(uintfptr_t)addr, data);
1227                                 break;
1228                         }
1229                         break;
1230                 case PT_DETACH:
1231                         /*
1232                          * Clear P_TRACED before reparenting
1233                          * a detached process back to its original
1234                          * parent.  Otherwise the debugee will be set
1235                          * as an orphan of the debugger.
1236                          */
1237                         p->p_flag &= ~(P_TRACED | P_WAITED);
1238
1239                         /*
1240                          * Reset the process parent.
1241                          */
1242                         if (p->p_oppid != p->p_pptr->p_pid) {
1243                                 PROC_LOCK(p->p_pptr);
1244                                 sigqueue_take(p->p_ksi);
1245                                 PROC_UNLOCK(p->p_pptr);
1246
1247                                 pp = proc_realparent(p);
1248                                 proc_reparent(p, pp, false);
1249                                 if (pp == initproc)
1250                                         p->p_sigparent = SIGCHLD;
1251                                 CTR3(KTR_PTRACE,
1252                             "PT_DETACH: pid %d reparented to pid %d, sig %d",
1253                                     p->p_pid, pp->p_pid, data);
1254                         } else {
1255                                 CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1256                                     p->p_pid, data);
1257                         }
1258
1259                         p->p_ptevents = 0;
1260                         FOREACH_THREAD_IN_PROC(p, td3) {
1261                                 if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1262                                         sigqueue_delete(&td3->td_sigqueue,
1263                                             SIGSTOP);
1264                                 }
1265                                 td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1266                                     TDB_SUSPEND);
1267                         }
1268
1269                         if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1270                                 sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1271                                 p->p_flag2 &= ~P2_PTRACE_FSTP;
1272                         }
1273
1274                         /* should we send SIGCHLD? */
1275                         /* childproc_continued(p); */
1276                         break;
1277                 }
1278
1279                 sx_xunlock(&proctree_lock);
1280                 proctree_locked = false;
1281
1282         sendsig:
1283                 MPASS(!proctree_locked);
1284
1285                 /*
1286                  * Clear the pending event for the thread that just
1287                  * reported its event (p_xthread).  This may not be
1288                  * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1289                  * the debugger is resuming a different thread.
1290                  *
1291                  * Deliver any pending signal via the reporting thread.
1292                  */
1293                 MPASS(p->p_xthread != NULL);
1294                 p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1295                 p->p_xthread->td_xsig = data;
1296                 p->p_xthread = NULL;
1297                 p->p_xsig = data;
1298
1299                 /*
1300                  * P_WKILLED is insurance that a PT_KILL/SIGKILL
1301                  * always works immediately, even if another thread is
1302                  * unsuspended first and attempts to handle a
1303                  * different signal or if the POSIX.1b style signal
1304                  * queue cannot accommodate any new signals.
1305                  */
1306                 if (data == SIGKILL)
1307                         proc_wkilled(p);
1308
1309                 /*
1310                  * Unsuspend all threads.  To leave a thread
1311                  * suspended, use PT_SUSPEND to suspend it before
1312                  * continuing the process.
1313                  */
1314                 ptrace_unsuspend(p);
1315                 break;
1316
1317         case PT_WRITE_I:
1318         case PT_WRITE_D:
1319                 td2->td_dbgflags |= TDB_USERWR;
1320                 PROC_UNLOCK(p);
1321                 error = 0;
1322                 if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1323                     sizeof(int)) != sizeof(int))
1324                         error = ENOMEM;
1325                 else
1326                         CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1327                             p->p_pid, addr, data);
1328                 PROC_LOCK(p);
1329                 break;
1330
1331         case PT_READ_I:
1332         case PT_READ_D:
1333                 PROC_UNLOCK(p);
1334                 error = tmp = 0;
1335                 if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1336                     sizeof(int)) != sizeof(int))
1337                         error = ENOMEM;
1338                 else
1339                         CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1340                             p->p_pid, addr, tmp);
1341                 td->td_retval[0] = tmp;
1342                 PROC_LOCK(p);
1343                 break;
1344
1345         case PT_IO:
1346                 piod = addr;
1347                 iov.iov_base = piod->piod_addr;
1348                 iov.iov_len = piod->piod_len;
1349                 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1350                 uio.uio_resid = piod->piod_len;
1351                 uio.uio_iov = &iov;
1352                 uio.uio_iovcnt = 1;
1353                 uio.uio_segflg = UIO_USERSPACE;
1354                 uio.uio_td = td;
1355                 switch (piod->piod_op) {
1356                 case PIOD_READ_D:
1357                 case PIOD_READ_I:
1358                         CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1359                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1360                         uio.uio_rw = UIO_READ;
1361                         break;
1362                 case PIOD_WRITE_D:
1363                 case PIOD_WRITE_I:
1364                         CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1365                             p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1366                         td2->td_dbgflags |= TDB_USERWR;
1367                         uio.uio_rw = UIO_WRITE;
1368                         break;
1369                 default:
1370                         error = EINVAL;
1371                         goto out;
1372                 }
1373                 PROC_UNLOCK(p);
1374                 error = proc_rwmem(p, &uio);
1375                 piod->piod_len -= uio.uio_resid;
1376                 PROC_LOCK(p);
1377                 break;
1378
1379         case PT_KILL:
1380                 CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1381                 data = SIGKILL;
1382                 goto sendsig;   /* in PT_CONTINUE above */
1383
1384         case PT_SETREGS:
1385                 CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1386                     p->p_pid);
1387                 td2->td_dbgflags |= TDB_USERWR;
1388                 error = PROC_WRITE(regs, td2, addr);
1389                 break;
1390
1391         case PT_GETREGS:
1392                 CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1393                     p->p_pid);
1394                 error = PROC_READ(regs, td2, addr);
1395                 break;
1396
1397         case PT_SETFPREGS:
1398                 CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1399                     p->p_pid);
1400                 td2->td_dbgflags |= TDB_USERWR;
1401                 error = PROC_WRITE(fpregs, td2, addr);
1402                 break;
1403
1404         case PT_GETFPREGS:
1405                 CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1406                     p->p_pid);
1407                 error = PROC_READ(fpregs, td2, addr);
1408                 break;
1409
1410         case PT_SETDBREGS:
1411                 CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1412                     p->p_pid);
1413                 td2->td_dbgflags |= TDB_USERWR;
1414                 error = PROC_WRITE(dbregs, td2, addr);
1415                 break;
1416
1417         case PT_GETDBREGS:
1418                 CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1419                     p->p_pid);
1420                 error = PROC_READ(dbregs, td2, addr);
1421                 break;
1422
1423         case PT_SETREGSET:
1424                 CTR2(KTR_PTRACE, "PT_SETREGSET: tid %d (pid %d)", td2->td_tid,
1425                     p->p_pid);
1426                 error = proc_write_regset(td2, data, addr);
1427                 break;
1428
1429         case PT_GETREGSET:
1430                 CTR2(KTR_PTRACE, "PT_GETREGSET: tid %d (pid %d)", td2->td_tid,
1431                     p->p_pid);
1432                 error = proc_read_regset(td2, data, addr);
1433                 break;
1434
1435         case PT_LWPINFO:
1436                 if (data <= 0 || data > sizeof(*pl)) {
1437                         error = EINVAL;
1438                         break;
1439                 }
1440                 pl = addr;
1441                 bzero(pl, sizeof(*pl));
1442                 pl->pl_lwpid = td2->td_tid;
1443                 pl->pl_event = PL_EVENT_NONE;
1444                 pl->pl_flags = 0;
1445                 if (td2->td_dbgflags & TDB_XSIG) {
1446                         pl->pl_event = PL_EVENT_SIGNAL;
1447                         if (td2->td_si.si_signo != 0 &&
1448                             data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1449                             + sizeof(pl->pl_siginfo)){
1450                                 pl->pl_flags |= PL_FLAG_SI;
1451                                 pl->pl_siginfo = td2->td_si;
1452                         }
1453                 }
1454                 if (td2->td_dbgflags & TDB_SCE)
1455                         pl->pl_flags |= PL_FLAG_SCE;
1456                 else if (td2->td_dbgflags & TDB_SCX)
1457                         pl->pl_flags |= PL_FLAG_SCX;
1458                 if (td2->td_dbgflags & TDB_EXEC)
1459                         pl->pl_flags |= PL_FLAG_EXEC;
1460                 if (td2->td_dbgflags & TDB_FORK) {
1461                         pl->pl_flags |= PL_FLAG_FORKED;
1462                         pl->pl_child_pid = td2->td_dbg_forked;
1463                         if (td2->td_dbgflags & TDB_VFORK)
1464                                 pl->pl_flags |= PL_FLAG_VFORKED;
1465                 } else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1466                     TDB_VFORK)
1467                         pl->pl_flags |= PL_FLAG_VFORK_DONE;
1468                 if (td2->td_dbgflags & TDB_CHILD)
1469                         pl->pl_flags |= PL_FLAG_CHILD;
1470                 if (td2->td_dbgflags & TDB_BORN)
1471                         pl->pl_flags |= PL_FLAG_BORN;
1472                 if (td2->td_dbgflags & TDB_EXIT)
1473                         pl->pl_flags |= PL_FLAG_EXITED;
1474                 pl->pl_sigmask = td2->td_sigmask;
1475                 pl->pl_siglist = td2->td_siglist;
1476                 strcpy(pl->pl_tdname, td2->td_name);
1477                 if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1478                         pl->pl_syscall_code = td2->td_sa.code;
1479                         pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1480                 } else {
1481                         pl->pl_syscall_code = 0;
1482                         pl->pl_syscall_narg = 0;
1483                 }
1484                 CTR6(KTR_PTRACE,
1485     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1486                     td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1487                     pl->pl_child_pid, pl->pl_syscall_code);
1488                 break;
1489
1490         case PT_GETNUMLWPS:
1491                 CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1492                     p->p_numthreads);
1493                 td->td_retval[0] = p->p_numthreads;
1494                 break;
1495
1496         case PT_GETLWPLIST:
1497                 CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1498                     p->p_pid, data, p->p_numthreads);
1499                 if (data <= 0) {
1500                         error = EINVAL;
1501                         break;
1502                 }
1503                 num = imin(p->p_numthreads, data);
1504                 PROC_UNLOCK(p);
1505                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1506                 tmp = 0;
1507                 PROC_LOCK(p);
1508                 FOREACH_THREAD_IN_PROC(p, td2) {
1509                         if (tmp >= num)
1510                                 break;
1511                         buf[tmp++] = td2->td_tid;
1512                 }
1513                 PROC_UNLOCK(p);
1514                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1515                 free(buf, M_TEMP);
1516                 if (!error)
1517                         td->td_retval[0] = tmp;
1518                 PROC_LOCK(p);
1519                 break;
1520
1521         case PT_VM_TIMESTAMP:
1522                 CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1523                     p->p_pid, p->p_vmspace->vm_map.timestamp);
1524                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1525                 break;
1526
1527         case PT_VM_ENTRY:
1528                 PROC_UNLOCK(p);
1529                 error = ptrace_vm_entry(td, p, addr);
1530                 PROC_LOCK(p);
1531                 break;
1532
1533         case PT_COREDUMP:
1534                 pc = addr;
1535                 CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1536                     p->p_pid, pc->pc_fd);
1537
1538                 if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1539                         error = EINVAL;
1540                         break;
1541                 }
1542                 PROC_UNLOCK(p);
1543
1544                 tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1545                 fp = NULL;
1546                 error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1547                 if (error != 0)
1548                         goto coredump_cleanup_nofp;
1549                 if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1550                         error = EPIPE;
1551                         goto coredump_cleanup;
1552                 }
1553
1554                 PROC_LOCK(p);
1555                 error = proc_can_ptrace(td, p);
1556                 if (error != 0)
1557                         goto coredump_cleanup_locked;
1558
1559                 td2 = ptrace_sel_coredump_thread(p);
1560                 if (td2 == NULL) {
1561                         error = EBUSY;
1562                         goto coredump_cleanup_locked;
1563                 }
1564                 KASSERT((td2->td_dbgflags & TDB_COREDUMPRQ) == 0,
1565                     ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1566
1567                 tcq->tc_vp = fp->f_vnode;
1568                 tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1569                 tcq->tc_flags = SVC_PT_COREDUMP;
1570                 if ((pc->pc_flags & PC_COMPRESS) == 0)
1571                         tcq->tc_flags |= SVC_NOCOMPRESS;
1572                 if ((pc->pc_flags & PC_ALL) != 0)
1573                         tcq->tc_flags |= SVC_ALL;
1574                 td2->td_coredump = tcq;
1575                 td2->td_dbgflags |= TDB_COREDUMPRQ;
1576                 thread_run_flash(td2);
1577                 while ((td2->td_dbgflags & TDB_COREDUMPRQ) != 0)
1578                         msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1579                 error = tcq->tc_error;
1580 coredump_cleanup_locked:
1581                 PROC_UNLOCK(p);
1582 coredump_cleanup:
1583                 fdrop(fp, td);
1584 coredump_cleanup_nofp:
1585                 free(tcq, M_TEMP);
1586                 PROC_LOCK(p);
1587                 break;
1588
1589         default:
1590 #ifdef __HAVE_PTRACE_MACHDEP
1591                 if (req >= PT_FIRSTMACH) {
1592                         PROC_UNLOCK(p);
1593                         error = cpu_ptrace(td2, req, addr, data);
1594                         PROC_LOCK(p);
1595                 } else
1596 #endif
1597                         /* Unknown request. */
1598                         error = EINVAL;
1599                 break;
1600         }
1601 out:
1602         /* Drop our hold on this process now that the request has completed. */
1603         _PRELE(p);
1604 fail:
1605         if (p2_req_set) {
1606                 if ((p->p_flag2 & P2_PTRACEREQ) != 0)
1607                         wakeup(&p->p_flag2);
1608                 p->p_flag2 &= ~P2_PTRACEREQ;
1609         }
1610         PROC_UNLOCK(p);
1611         if (proctree_locked)
1612                 sx_xunlock(&proctree_lock);
1613         return (error);
1614 }
1615 #undef PROC_READ
1616 #undef PROC_WRITE