sys/kern/sys_process.c

   1 /*-
   2  * Copyright (c) 1994, Sean Eric Fagan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Sean Eric Fagan.
  16  * 4. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include "opt_compat.h"
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/lock.h>
  40 #include <sys/mutex.h>
  41 #include <sys/syscallsubr.h>
  42 #include <sys/sysent.h>
  43 #include <sys/sysproto.h>
  44 #include <sys/proc.h>
  45 #include <sys/vnode.h>
  46 #include <sys/ptrace.h>
  47 #include <sys/sx.h>
  48 #include <sys/malloc.h>
  49 #include <sys/signalvar.h>
  50
  51 #include <machine/reg.h>
  52
  53 #include <security/audit/audit.h>
  54
  55 #include <vm/vm.h>
  56 #include <vm/pmap.h>
  57 #include <vm/vm_extern.h>
  58 #include <vm/vm_map.h>
  59 #include <vm/vm_kern.h>
  60 #include <vm/vm_object.h>
  61 #include <vm/vm_page.h>
  62 #include <vm/vm_pager.h>
  63 #include <vm/vm_param.h>
  64
  65 #ifdef COMPAT_FREEBSD32
  66 #include <sys/procfs.h>
  67
  68 struct ptrace_io_desc32 {
  69         int             piod_op;
  70         u_int32_t       piod_offs;
  71         u_int32_t       piod_addr;
  72         u_int32_t       piod_len;
  73 };
  74
  75 struct ptrace_vm_entry32 {
  76         int             pve_entry;
  77         int             pve_timestamp;
  78         uint32_t        pve_start;
  79         uint32_t        pve_end;
  80         uint32_t        pve_offset;
  81         u_int           pve_prot;
  82         u_int           pve_pathlen;
  83         int32_t         pve_fileid;
  84         u_int           pve_fsid;
  85         uint32_t        pve_path;
  86 };
  87
  88 #endif
  89
  90 /*
  91  * Functions implemented using PROC_ACTION():
  92  *
  93  * proc_read_regs(proc, regs)
  94  *      Get the current user-visible register set from the process
  95  *      and copy it into the regs structure (<machine/reg.h>).
  96  *      The process is stopped at the time read_regs is called.
  97  *
  98  * proc_write_regs(proc, regs)
  99  *      Update the current register set from the passed in regs
 100  *      structure.  Take care to avoid clobbering special CPU
 101  *      registers or privileged bits in the PSL.
 102  *      Depending on the architecture this may have fix-up work to do,
 103  *      especially if the IAR or PCW are modified.
 104  *      The process is stopped at the time write_regs is called.
 105  *
 106  * proc_read_fpregs, proc_write_fpregs
 107  *      deal with the floating point register set, otherwise as above.
 108  *
 109  * proc_read_dbregs, proc_write_dbregs
 110  *      deal with the processor debug register set, otherwise as above.
 111  *
 112  * proc_sstep(proc)
 113  *      Arrange for the process to trap after executing a single instruction.
 114  */
 115
 116 #define PROC_ACTION(action) do {                                        \
 117         int error;                                                      \
 118                                                                         \
 119         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
 120         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
 121                 error = EIO;                                            \
 122         else                                                            \
 123                 error = (action);                                       \
 124         return (error);                                                 \
 125 } while(0)
 126
 127 int
 128 proc_read_regs(struct thread *td, struct reg *regs)
 129 {
 130
 131         PROC_ACTION(fill_regs(td, regs));
 132 }
 133
 134 int
 135 proc_write_regs(struct thread *td, struct reg *regs)
 136 {
 137
 138         PROC_ACTION(set_regs(td, regs));
 139 }
 140
 141 int
 142 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
 143 {
 144
 145         PROC_ACTION(fill_dbregs(td, dbregs));
 146 }
 147
 148 int
 149 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
 150 {
 151
 152         PROC_ACTION(set_dbregs(td, dbregs));
 153 }
 154
 155 /*
 156  * Ptrace doesn't support fpregs at all, and there are no security holes
 157  * or translations for fpregs, so we can just copy them.
 158  */
 159 int
 160 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
 161 {
 162
 163         PROC_ACTION(fill_fpregs(td, fpregs));
 164 }
 165
 166 int
 167 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
 168 {
 169
 170         PROC_ACTION(set_fpregs(td, fpregs));
 171 }
 172
 173 #ifdef COMPAT_FREEBSD32
 174 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
 175 int
 176 proc_read_regs32(struct thread *td, struct reg32 *regs32)
 177 {
 178
 179         PROC_ACTION(fill_regs32(td, regs32));
 180 }
 181
 182 int
 183 proc_write_regs32(struct thread *td, struct reg32 *regs32)
 184 {
 185
 186         PROC_ACTION(set_regs32(td, regs32));
 187 }
 188
 189 int
 190 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 191 {
 192
 193         PROC_ACTION(fill_dbregs32(td, dbregs32));
 194 }
 195
 196 int
 197 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 198 {
 199
 200         PROC_ACTION(set_dbregs32(td, dbregs32));
 201 }
 202
 203 int
 204 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 205 {
 206
 207         PROC_ACTION(fill_fpregs32(td, fpregs32));
 208 }
 209
 210 int
 211 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 212 {
 213
 214         PROC_ACTION(set_fpregs32(td, fpregs32));
 215 }
 216 #endif
 217
 218 int
 219 proc_sstep(struct thread *td)
 220 {
 221
 222         PROC_ACTION(ptrace_single_step(td));
 223 }
 224
 225 int
 226 proc_rwmem(struct proc *p, struct uio *uio)
 227 {
 228         vm_map_t map;
 229         vm_object_t backing_object, object;
 230         vm_offset_t pageno;             /* page number */
 231         vm_prot_t reqprot;
 232         int error, writing;
 233
 234         /*
 235          * Assert that someone has locked this vmspace.  (Should be
 236          * curthread but we can't assert that.)  This keeps the process
 237          * from exiting out from under us until this operation completes.
 238          */
 239         KASSERT(p->p_lock >= 1, ("%s: process %p (pid %d) not held", __func__,
 240             p, p->p_pid));
 241
 242         /*
 243          * The map we want...
 244          */
 245         map = &p->p_vmspace->vm_map;
 246
 247         writing = uio->uio_rw == UIO_WRITE;
 248         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 249
 250         /*
 251          * Only map in one page at a time.  We don't have to, but it
 252          * makes things easier.  This way is trivial - right?
 253          */
 254         do {
 255                 vm_map_t tmap;
 256                 vm_offset_t uva;
 257                 int page_offset;                /* offset into page */
 258                 vm_map_entry_t out_entry;
 259                 vm_prot_t out_prot;
 260                 boolean_t wired;
 261                 vm_pindex_t pindex;
 262                 u_int len;
 263                 vm_page_t m;
 264
 265                 object = NULL;
 266
 267                 uva = (vm_offset_t)uio->uio_offset;
 268
 269                 /*
 270                  * Get the page number of this segment.
 271                  */
 272                 pageno = trunc_page(uva);
 273                 page_offset = uva - pageno;
 274
 275                 /*
 276                  * How many bytes to copy
 277                  */
 278                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
 279
 280                 /*
 281                  * Fault the page on behalf of the process
 282                  */
 283                 error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL);
 284                 if (error) {
 285                         if (error == KERN_RESOURCE_SHORTAGE)
 286                                 error = ENOMEM;
 287                         else
 288                                 error = EFAULT;
 289                         break;
 290                 }
 291
 292                 /*
 293                  * Now we need to get the page.  out_entry and wired
 294                  * aren't used.  One would think the vm code
 295                  * would be a *bit* nicer...  We use tmap because
 296                  * vm_map_lookup() can change the map argument.
 297                  */
 298                 tmap = map;
 299                 error = vm_map_lookup(&tmap, pageno, reqprot, &out_entry,
 300                     &object, &pindex, &out_prot, &wired);
 301                 if (error) {
 302                         error = EFAULT;
 303                         break;
 304                 }
 305                 VM_OBJECT_LOCK(object);
 306                 while ((m = vm_page_lookup(object, pindex)) == NULL &&
 307                     !writing &&
 308                     (backing_object = object->backing_object) != NULL) {
 309                         /*
 310                          * Allow fallback to backing objects if we are reading.
 311                          */
 312                         VM_OBJECT_LOCK(backing_object);
 313                         pindex += OFF_TO_IDX(object->backing_object_offset);
 314                         VM_OBJECT_UNLOCK(object);
 315                         object = backing_object;
 316                 }
 317                 if (writing && m != NULL) {
 318                         vm_page_dirty(m);
 319                         vm_pager_page_unswapped(m);
 320                 }
 321                 VM_OBJECT_UNLOCK(object);
 322                 if (m == NULL) {
 323                         vm_map_lookup_done(tmap, out_entry);
 324                         error = EFAULT;
 325                         break;
 326                 }
 327
 328                 /*
 329                  * Hold the page in memory.
 330                  */
 331                 vm_page_lock(m);
 332                 vm_page_hold(m);
 333                 vm_page_unlock(m);
 334
 335                 /*
 336                  * We're done with tmap now.
 337                  */
 338                 vm_map_lookup_done(tmap, out_entry);
 339
 340                 /*
 341                  * Now do the i/o move.
 342                  */
 343                 error = uiomove_fromphys(&m, page_offset, len, uio);
 344
 345                 /* Make the I-cache coherent for breakpoints. */
 346                 if (!error && writing && (out_prot & VM_PROT_EXECUTE))
 347                         vm_sync_icache(map, uva, len);
 348
 349                 /*
 350                  * Release the page.
 351                  */
 352                 vm_page_lock(m);
 353                 vm_page_unhold(m);
 354                 vm_page_unlock(m);
 355
 356         } while (error == 0 && uio->uio_resid > 0);
 357
 358         return (error);
 359 }
 360
 361 static int
 362 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 363 {
 364         struct vattr vattr;
 365         vm_map_t map;
 366         vm_map_entry_t entry;
 367         vm_object_t obj, tobj, lobj;
 368         struct vmspace *vm;
 369         struct vnode *vp;
 370         char *freepath, *fullpath;
 371         u_int pathlen;
 372         int error, index, vfslocked;
 373
 374         error = 0;
 375         obj = NULL;
 376
 377         vm = vmspace_acquire_ref(p);
 378         map = &vm->vm_map;
 379         vm_map_lock_read(map);
 380
 381         do {
 382                 entry = map->header.next;
 383                 index = 0;
 384                 while (index < pve->pve_entry && entry != &map->header) {
 385                         entry = entry->next;
 386                         index++;
 387                 }
 388                 if (index != pve->pve_entry) {
 389                         error = EINVAL;
 390                         break;
 391                 }
 392                 while (entry != &map->header &&
 393                     (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
 394                         entry = entry->next;
 395                         index++;
 396                 }
 397                 if (entry == &map->header) {
 398                         error = ENOENT;
 399                         break;
 400                 }
 401
 402                 /* We got an entry. */
 403                 pve->pve_entry = index + 1;
 404                 pve->pve_timestamp = map->timestamp;
 405                 pve->pve_start = entry->start;
 406                 pve->pve_end = entry->end - 1;
 407                 pve->pve_offset = entry->offset;
 408                 pve->pve_prot = entry->protection;
 409
 410                 /* Backing object's path needed? */
 411                 if (pve->pve_pathlen == 0)
 412                         break;
 413
 414                 pathlen = pve->pve_pathlen;
 415                 pve->pve_pathlen = 0;
 416
 417                 obj = entry->object.vm_object;
 418                 if (obj != NULL)
 419                         VM_OBJECT_LOCK(obj);
 420         } while (0);
 421
 422         vm_map_unlock_read(map);
 423         vmspace_free(vm);
 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_LOCK(tobj);
 433                         if (lobj != obj)
 434                                 VM_OBJECT_UNLOCK(lobj);
 435                         lobj = tobj;
 436                         pve->pve_offset += tobj->backing_object_offset;
 437                 }
 438                 vp = (lobj->type == OBJT_VNODE) ? lobj->handle : NULL;
 439                 if (vp != NULL)
 440                         vref(vp);
 441                 if (lobj != obj)
 442                         VM_OBJECT_UNLOCK(lobj);
 443                 VM_OBJECT_UNLOCK(obj);
 444
 445                 if (vp != NULL) {
 446                         freepath = NULL;
 447                         fullpath = NULL;
 448                         vn_fullpath(td, vp, &fullpath, &freepath);
 449                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 450                         vn_lock(vp, LK_SHARED | LK_RETRY);
 451                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
 452                                 pve->pve_fileid = vattr.va_fileid;
 453                                 pve->pve_fsid = vattr.va_fsid;
 454                         }
 455                         vput(vp);
 456                         VFS_UNLOCK_GIANT(vfslocked);
 457
 458                         if (fullpath != NULL) {
 459                                 pve->pve_pathlen = strlen(fullpath) + 1;
 460                                 if (pve->pve_pathlen <= pathlen) {
 461                                         error = copyout(fullpath, pve->pve_path,
 462                                             pve->pve_pathlen);
 463                                 } else
 464                                         error = ENAMETOOLONG;
 465                         }
 466                         if (freepath != NULL)
 467                                 free(freepath, M_TEMP);
 468                 }
 469         }
 470
 471         return (error);
 472 }
 473
 474 #ifdef COMPAT_FREEBSD32
 475 static int
 476 ptrace_vm_entry32(struct thread *td, struct proc *p,
 477     struct ptrace_vm_entry32 *pve32)
 478 {
 479         struct ptrace_vm_entry pve;
 480         int error;
 481
 482         pve.pve_entry = pve32->pve_entry;
 483         pve.pve_pathlen = pve32->pve_pathlen;
 484         pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
 485
 486         error = ptrace_vm_entry(td, p, &pve);
 487         if (error == 0) {
 488                 pve32->pve_entry = pve.pve_entry;
 489                 pve32->pve_timestamp = pve.pve_timestamp;
 490                 pve32->pve_start = pve.pve_start;
 491                 pve32->pve_end = pve.pve_end;
 492                 pve32->pve_offset = pve.pve_offset;
 493                 pve32->pve_prot = pve.pve_prot;
 494                 pve32->pve_fileid = pve.pve_fileid;
 495                 pve32->pve_fsid = pve.pve_fsid;
 496         }
 497
 498         pve32->pve_pathlen = pve.pve_pathlen;
 499         return (error);
 500 }
 501 #endif /* COMPAT_FREEBSD32 */
 502
 503 /*
 504  * Process debugging system call.
 505  */
 506 #ifndef _SYS_SYSPROTO_H_
 507 struct ptrace_args {
 508         int     req;
 509         pid_t   pid;
 510         caddr_t addr;
 511         int     data;
 512 };
 513 #endif
 514
 515 #ifdef COMPAT_FREEBSD32
 516 /*
 517  * This CPP subterfuge is to try and reduce the number of ifdefs in
 518  * the body of the code.
 519  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
 520  * becomes either:
 521  *   copyin(uap->addr, &r.reg, sizeof r.reg);
 522  * or
 523  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
 524  * .. except this is done at runtime.
 525  */
 526 #define COPYIN(u, k, s)         wrap32 ? \
 527         copyin(u, k ## 32, s ## 32) : \
 528         copyin(u, k, s)
 529 #define COPYOUT(k, u, s)        wrap32 ? \
 530         copyout(k ## 32, u, s ## 32) : \
 531         copyout(k, u, s)
 532 #else
 533 #define COPYIN(u, k, s)         copyin(u, k, s)
 534 #define COPYOUT(k, u, s)        copyout(k, u, s)
 535 #endif
 536 int
 537 ptrace(struct thread *td, struct ptrace_args *uap)
 538 {
 539         /*
 540          * XXX this obfuscation is to reduce stack usage, but the register
 541          * structs may be too large to put on the stack anyway.
 542          */
 543         union {
 544                 struct ptrace_io_desc piod;
 545                 struct ptrace_lwpinfo pl;
 546                 struct ptrace_vm_entry pve;
 547                 struct dbreg dbreg;
 548                 struct fpreg fpreg;
 549                 struct reg reg;
 550 #ifdef COMPAT_FREEBSD32
 551                 struct dbreg32 dbreg32;
 552                 struct fpreg32 fpreg32;
 553                 struct reg32 reg32;
 554                 struct ptrace_io_desc32 piod32;
 555                 struct ptrace_vm_entry32 pve32;
 556 #endif
 557         } r;
 558         void *addr;
 559         int error = 0;
 560 #ifdef COMPAT_FREEBSD32
 561         int wrap32 = 0;
 562
 563         if (SV_CURPROC_FLAG(SV_ILP32))
 564                 wrap32 = 1;
 565 #endif
 566         AUDIT_ARG_PID(uap->pid);
 567         AUDIT_ARG_CMD(uap->req);
 568         AUDIT_ARG_VALUE(uap->data);
 569         addr = &r;
 570         switch (uap->req) {
 571         case PT_GETREGS:
 572         case PT_GETFPREGS:
 573         case PT_GETDBREGS:
 574         case PT_LWPINFO:
 575                 break;
 576         case PT_SETREGS:
 577                 error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
 578                 break;
 579         case PT_SETFPREGS:
 580                 error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
 581                 break;
 582         case PT_SETDBREGS:
 583                 error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
 584                 break;
 585         case PT_IO:
 586                 error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
 587                 break;
 588         case PT_VM_ENTRY:
 589                 error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
 590                 break;
 591         default:
 592                 addr = uap->addr;
 593                 break;
 594         }
 595         if (error)
 596                 return (error);
 597
 598         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
 599         if (error)
 600                 return (error);
 601
 602         switch (uap->req) {
 603         case PT_VM_ENTRY:
 604                 error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
 605                 break;
 606         case PT_IO:
 607                 error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
 608                 break;
 609         case PT_GETREGS:
 610                 error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
 611                 break;
 612         case PT_GETFPREGS:
 613                 error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
 614                 break;
 615         case PT_GETDBREGS:
 616                 error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
 617                 break;
 618         case PT_LWPINFO:
 619                 error = copyout(&r.pl, uap->addr, uap->data);
 620                 break;
 621         }
 622
 623         return (error);
 624 }
 625 #undef COPYIN
 626 #undef COPYOUT
 627
 628 #ifdef COMPAT_FREEBSD32
 629 /*
 630  *   PROC_READ(regs, td2, addr);
 631  * becomes either:
 632  *   proc_read_regs(td2, addr);
 633  * or
 634  *   proc_read_regs32(td2, addr);
 635  * .. except this is done at runtime.  There is an additional
 636  * complication in that PROC_WRITE disallows 32 bit consumers
 637  * from writing to 64 bit address space targets.
 638  */
 639 #define PROC_READ(w, t, a)      wrap32 ? \
 640         proc_read_ ## w ## 32(t, a) : \
 641         proc_read_ ## w (t, a)
 642 #define PROC_WRITE(w, t, a)     wrap32 ? \
 643         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
 644         proc_write_ ## w (t, a)
 645 #else
 646 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
 647 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
 648 #endif
 649
 650 int
 651 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 652 {
 653         struct iovec iov;
 654         struct uio uio;
 655         struct proc *curp, *p, *pp;
 656         struct thread *td2 = NULL;
 657         struct ptrace_io_desc *piod = NULL;
 658         struct ptrace_lwpinfo *pl;
 659         int error, write, tmp, num;
 660         int proctree_locked = 0;
 661         lwpid_t tid = 0, *buf;
 662 #ifdef COMPAT_FREEBSD32
 663         int wrap32 = 0, safe = 0;
 664         struct ptrace_io_desc32 *piod32 = NULL;
 665 #endif
 666
 667         curp = td->td_proc;
 668
 669         /* Lock proctree before locking the process. */
 670         switch (req) {
 671         case PT_TRACE_ME:
 672         case PT_ATTACH:
 673         case PT_STEP:
 674         case PT_CONTINUE:
 675         case PT_TO_SCE:
 676         case PT_TO_SCX:
 677         case PT_SYSCALL:
 678         case PT_DETACH:
 679                 sx_xlock(&proctree_lock);
 680                 proctree_locked = 1;
 681                 break;
 682         default:
 683                 break;
 684         }
 685
 686         write = 0;
 687         if (req == PT_TRACE_ME) {
 688                 p = td->td_proc;
 689                 PROC_LOCK(p);
 690         } else {
 691                 if (pid <= PID_MAX) {
 692                         if ((p = pfind(pid)) == NULL) {
 693                                 if (proctree_locked)
 694                                         sx_xunlock(&proctree_lock);
 695                                 return (ESRCH);
 696                         }
 697                 } else {
 698                         /* this is slow, should be optimized */
 699                         sx_slock(&allproc_lock);
 700                         FOREACH_PROC_IN_SYSTEM(p) {
 701                                 PROC_LOCK(p);
 702                                 FOREACH_THREAD_IN_PROC(p, td2) {
 703                                         if (td2->td_tid == pid)
 704                                                 break;
 705                                 }
 706                                 if (td2 != NULL)
 707                                         break; /* proc lock held */
 708                                 PROC_UNLOCK(p);
 709                         }
 710                         sx_sunlock(&allproc_lock);
 711                         if (p == NULL) {
 712                                 if (proctree_locked)
 713                                         sx_xunlock(&proctree_lock);
 714                                 return (ESRCH);
 715                         }
 716                         tid = pid;
 717                         pid = p->p_pid;
 718                 }
 719         }
 720         AUDIT_ARG_PROCESS(p);
 721
 722         if ((p->p_flag & P_WEXIT) != 0) {
 723                 error = ESRCH;
 724                 goto fail;
 725         }
 726         if ((error = p_cansee(td, p)) != 0)
 727                 goto fail;
 728
 729         if ((error = p_candebug(td, p)) != 0)
 730                 goto fail;
 731
 732         /*
 733          * System processes can't be debugged.
 734          */
 735         if ((p->p_flag & P_SYSTEM) != 0) {
 736                 error = EINVAL;
 737                 goto fail;
 738         }
 739
 740         if (tid == 0) {
 741                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
 742                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
 743                         td2 = p->p_xthread;
 744                 } else {
 745                         td2 = FIRST_THREAD_IN_PROC(p);
 746                 }
 747                 tid = td2->td_tid;
 748         }
 749
 750 #ifdef COMPAT_FREEBSD32
 751         /*
 752          * Test if we're a 32 bit client and what the target is.
 753          * Set the wrap controls accordingly.
 754          */
 755         if (SV_CURPROC_FLAG(SV_ILP32)) {
 756                 if (td2->td_proc->p_sysent->sv_flags & SV_ILP32)
 757                         safe = 1;
 758                 wrap32 = 1;
 759         }
 760 #endif
 761         /*
 762          * Permissions check
 763          */
 764         switch (req) {
 765         case PT_TRACE_ME:
 766                 /* Always legal. */
 767                 break;
 768
 769         case PT_ATTACH:
 770                 /* Self */
 771                 if (p->p_pid == td->td_proc->p_pid) {
 772                         error = EINVAL;
 773                         goto fail;
 774                 }
 775
 776                 /* Already traced */
 777                 if (p->p_flag & P_TRACED) {
 778                         error = EBUSY;
 779                         goto fail;
 780                 }
 781
 782                 /* Can't trace an ancestor if you're being traced. */
 783                 if (curp->p_flag & P_TRACED) {
 784                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
 785                                 if (pp == p) {
 786                                         error = EINVAL;
 787                                         goto fail;
 788                                 }
 789                         }
 790                 }
 791
 792
 793                 /* OK */
 794                 break;
 795
 796         case PT_CLEARSTEP:
 797                 /* Allow thread to clear single step for itself */
 798                 if (td->td_tid == tid)
 799                         break;
 800
 801                 /* FALLTHROUGH */
 802         default:
 803                 /* not being traced... */
 804                 if ((p->p_flag & P_TRACED) == 0) {
 805                         error = EPERM;
 806                         goto fail;
 807                 }
 808
 809                 /* not being traced by YOU */
 810                 if (p->p_pptr != td->td_proc) {
 811                         error = EBUSY;
 812                         goto fail;
 813                 }
 814
 815                 /* not currently stopped */
 816                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
 817                     p->p_suspcount != p->p_numthreads  ||
 818                     (p->p_flag & P_WAITED) == 0) {
 819                         error = EBUSY;
 820                         goto fail;
 821                 }
 822
 823                 if ((p->p_flag & P_STOPPED_TRACE) == 0) {
 824                         static int count = 0;
 825                         if (count++ == 0)
 826                                 printf("P_STOPPED_TRACE not set.\n");
 827                 }
 828
 829                 /* OK */
 830                 break;
 831         }
 832
 833         /* Keep this process around until we finish this request. */
 834         _PHOLD(p);
 835
 836 #ifdef FIX_SSTEP
 837         /*
 838          * Single step fixup ala procfs
 839          */
 840         FIX_SSTEP(td2);
 841 #endif
 842
 843         /*
 844          * Actually do the requests
 845          */
 846
 847         td->td_retval[0] = 0;
 848
 849         switch (req) {
 850         case PT_TRACE_ME:
 851                 /* set my trace flag and "owner" so it can read/write me */
 852                 p->p_flag |= P_TRACED;
 853                 p->p_oppid = p->p_pptr->p_pid;
 854                 break;
 855
 856         case PT_ATTACH:
 857                 /* security check done above */
 858                 p->p_flag |= P_TRACED;
 859                 p->p_oppid = p->p_pptr->p_pid;
 860                 if (p->p_pptr != td->td_proc)
 861                         proc_reparent(p, td->td_proc);
 862                 data = SIGSTOP;
 863                 goto sendsig;   /* in PT_CONTINUE below */
 864
 865         case PT_CLEARSTEP:
 866                 error = ptrace_clear_single_step(td2);
 867                 break;
 868
 869         case PT_SETSTEP:
 870                 error = ptrace_single_step(td2);
 871                 break;
 872
 873         case PT_SUSPEND:
 874                 td2->td_dbgflags |= TDB_SUSPEND;
 875                 thread_lock(td2);
 876                 td2->td_flags |= TDF_NEEDSUSPCHK;
 877                 thread_unlock(td2);
 878                 break;
 879
 880         case PT_RESUME:
 881                 td2->td_dbgflags &= ~TDB_SUSPEND;
 882                 break;
 883
 884         case PT_STEP:
 885         case PT_CONTINUE:
 886         case PT_TO_SCE:
 887         case PT_TO_SCX:
 888         case PT_SYSCALL:
 889         case PT_DETACH:
 890                 /* Zero means do not send any signal */
 891                 if (data < 0 || data > _SIG_MAXSIG) {
 892                         error = EINVAL;
 893                         break;
 894                 }
 895
 896                 switch (req) {
 897                 case PT_STEP:
 898                         error = ptrace_single_step(td2);
 899                         if (error)
 900                                 goto out;
 901                         break;
 902                 case PT_TO_SCE:
 903                         p->p_stops |= S_PT_SCE;
 904                         break;
 905                 case PT_TO_SCX:
 906                         p->p_stops |= S_PT_SCX;
 907                         break;
 908                 case PT_SYSCALL:
 909                         p->p_stops |= S_PT_SCE | S_PT_SCX;
 910                         break;
 911                 }
 912
 913                 if (addr != (void *)1) {
 914                         error = ptrace_set_pc(td2, (u_long)(uintfptr_t)addr);
 915                         if (error)
 916                                 break;
 917                 }
 918
 919                 if (req == PT_DETACH) {
 920                         /* reset process parent */
 921                         if (p->p_oppid != p->p_pptr->p_pid) {
 922                                 struct proc *pp;
 923
 924                                 PROC_LOCK(p->p_pptr);
 925                                 sigqueue_take(p->p_ksi);
 926                                 PROC_UNLOCK(p->p_pptr);
 927
 928                                 PROC_UNLOCK(p);
 929                                 pp = pfind(p->p_oppid);
 930                                 if (pp == NULL)
 931                                         pp = initproc;
 932                                 else
 933                                         PROC_UNLOCK(pp);
 934                                 PROC_LOCK(p);
 935                                 proc_reparent(p, pp);
 936                                 if (pp == initproc)
 937                                         p->p_sigparent = SIGCHLD;
 938                         }
 939                         p->p_flag &= ~(P_TRACED | P_WAITED);
 940                         p->p_oppid = 0;
 941
 942                         /* should we send SIGCHLD? */
 943                         /* childproc_continued(p); */
 944                 }
 945
 946         sendsig:
 947                 if (proctree_locked) {
 948                         sx_xunlock(&proctree_lock);
 949                         proctree_locked = 0;
 950                 }
 951                 p->p_xstat = data;
 952                 p->p_xthread = NULL;
 953                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
 954                         /* deliver or queue signal */
 955                         td2->td_dbgflags &= ~TDB_XSIG;
 956                         td2->td_xsig = data;
 957
 958                         if (req == PT_DETACH) {
 959                                 struct thread *td3;
 960                                 FOREACH_THREAD_IN_PROC(p, td3) {
 961                                         td3->td_dbgflags &= ~TDB_SUSPEND;
 962                                 }
 963                         }
 964                         /*
 965                          * unsuspend all threads, to not let a thread run,
 966                          * you should use PT_SUSPEND to suspend it before
 967                          * continuing process.
 968                          */
 969                         PROC_SLOCK(p);
 970                         p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
 971                         thread_unsuspend(p);
 972                         PROC_SUNLOCK(p);
 973                 } else {
 974                         if (data)
 975                                 psignal(p, data);
 976                 }
 977                 break;
 978
 979         case PT_WRITE_I:
 980         case PT_WRITE_D:
 981                 td2->td_dbgflags |= TDB_USERWR;
 982                 write = 1;
 983                 /* FALLTHROUGH */
 984         case PT_READ_I:
 985         case PT_READ_D:
 986                 PROC_UNLOCK(p);
 987                 tmp = 0;
 988                 /* write = 0 set above */
 989                 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
 990                 iov.iov_len = sizeof(int);
 991                 uio.uio_iov = &iov;
 992                 uio.uio_iovcnt = 1;
 993                 uio.uio_offset = (off_t)(uintptr_t)addr;
 994                 uio.uio_resid = sizeof(int);
 995                 uio.uio_segflg = UIO_SYSSPACE;  /* i.e.: the uap */
 996                 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
 997                 uio.uio_td = td;
 998                 error = proc_rwmem(p, &uio);
 999                 if (uio.uio_resid != 0) {
1000                         /*
1001                          * XXX proc_rwmem() doesn't currently return ENOSPC,
1002                          * so I think write() can bogusly return 0.
1003                          * XXX what happens for short writes?  We don't want
1004                          * to write partial data.
1005                          * XXX proc_rwmem() returns EPERM for other invalid
1006                          * addresses.  Convert this to EINVAL.  Does this
1007                          * clobber returns of EPERM for other reasons?
1008                          */
1009                         if (error == 0 || error == ENOSPC || error == EPERM)
1010                                 error = EINVAL; /* EOF */
1011                 }
1012                 if (!write)
1013                         td->td_retval[0] = tmp;
1014                 PROC_LOCK(p);
1015                 break;
1016
1017         case PT_IO:
1018 #ifdef COMPAT_FREEBSD32
1019                 if (wrap32) {
1020                         piod32 = addr;
1021                         iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1022                         iov.iov_len = piod32->piod_len;
1023                         uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1024                         uio.uio_resid = piod32->piod_len;
1025                 } else
1026 #endif
1027                 {
1028                         piod = addr;
1029                         iov.iov_base = piod->piod_addr;
1030                         iov.iov_len = piod->piod_len;
1031                         uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1032                         uio.uio_resid = piod->piod_len;
1033                 }
1034                 uio.uio_iov = &iov;
1035                 uio.uio_iovcnt = 1;
1036                 uio.uio_segflg = UIO_USERSPACE;
1037                 uio.uio_td = td;
1038 #ifdef COMPAT_FREEBSD32
1039                 tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1040 #else
1041                 tmp = piod->piod_op;
1042 #endif
1043                 switch (tmp) {
1044                 case PIOD_READ_D:
1045                 case PIOD_READ_I:
1046                         uio.uio_rw = UIO_READ;
1047                         break;
1048                 case PIOD_WRITE_D:
1049                 case PIOD_WRITE_I:
1050                         td2->td_dbgflags |= TDB_USERWR;
1051                         uio.uio_rw = UIO_WRITE;
1052                         break;
1053                 default:
1054                         error = EINVAL;
1055                         goto out;
1056                 }
1057                 PROC_UNLOCK(p);
1058                 error = proc_rwmem(p, &uio);
1059 #ifdef COMPAT_FREEBSD32
1060                 if (wrap32)
1061                         piod32->piod_len -= uio.uio_resid;
1062                 else
1063 #endif
1064                         piod->piod_len -= uio.uio_resid;
1065                 PROC_LOCK(p);
1066                 break;
1067
1068         case PT_KILL:
1069                 data = SIGKILL;
1070                 goto sendsig;   /* in PT_CONTINUE above */
1071
1072         case PT_SETREGS:
1073                 td2->td_dbgflags |= TDB_USERWR;
1074                 error = PROC_WRITE(regs, td2, addr);
1075                 break;
1076
1077         case PT_GETREGS:
1078                 error = PROC_READ(regs, td2, addr);
1079                 break;
1080
1081         case PT_SETFPREGS:
1082                 td2->td_dbgflags |= TDB_USERWR;
1083                 error = PROC_WRITE(fpregs, td2, addr);
1084                 break;
1085
1086         case PT_GETFPREGS:
1087                 error = PROC_READ(fpregs, td2, addr);
1088                 break;
1089
1090         case PT_SETDBREGS:
1091                 td2->td_dbgflags |= TDB_USERWR;
1092                 error = PROC_WRITE(dbregs, td2, addr);
1093                 break;
1094
1095         case PT_GETDBREGS:
1096                 error = PROC_READ(dbregs, td2, addr);
1097                 break;
1098
1099         case PT_LWPINFO:
1100                 if (data <= 0 || data > sizeof(*pl)) {
1101                         error = EINVAL;
1102                         break;
1103                 }
1104                 pl = addr;
1105                 pl->pl_lwpid = td2->td_tid;
1106                 if (td2->td_dbgflags & TDB_XSIG)
1107                         pl->pl_event = PL_EVENT_SIGNAL;
1108                 else
1109                         pl->pl_event = 0;
1110                 pl->pl_flags = 0;
1111                 pl->pl_sigmask = td2->td_sigmask;
1112                 pl->pl_siglist = td2->td_siglist;
1113                 break;
1114
1115         case PT_GETNUMLWPS:
1116                 td->td_retval[0] = p->p_numthreads;
1117                 break;
1118
1119         case PT_GETLWPLIST:
1120                 if (data <= 0) {
1121                         error = EINVAL;
1122                         break;
1123                 }
1124                 num = imin(p->p_numthreads, data);
1125                 PROC_UNLOCK(p);
1126                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1127                 tmp = 0;
1128                 PROC_LOCK(p);
1129                 FOREACH_THREAD_IN_PROC(p, td2) {
1130                         if (tmp >= num)
1131                                 break;
1132                         buf[tmp++] = td2->td_tid;
1133                 }
1134                 PROC_UNLOCK(p);
1135                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1136                 free(buf, M_TEMP);
1137                 if (!error)
1138                         td->td_retval[0] = tmp;
1139                 PROC_LOCK(p);
1140                 break;
1141
1142         case PT_VM_TIMESTAMP:
1143                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1144                 break;
1145
1146         case PT_VM_ENTRY:
1147                 PROC_UNLOCK(p);
1148 #ifdef COMPAT_FREEBSD32
1149                 if (wrap32)
1150                         error = ptrace_vm_entry32(td, p, addr);
1151                 else
1152 #endif
1153                 error = ptrace_vm_entry(td, p, addr);
1154                 PROC_LOCK(p);
1155                 break;
1156
1157         default:
1158 #ifdef __HAVE_PTRACE_MACHDEP
1159                 if (req >= PT_FIRSTMACH) {
1160                         PROC_UNLOCK(p);
1161                         error = cpu_ptrace(td2, req, addr, data);
1162                         PROC_LOCK(p);
1163                 } else
1164 #endif
1165                         /* Unknown request. */
1166                         error = EINVAL;
1167                 break;
1168         }
1169
1170 out:
1171         /* Drop our hold on this process now that the request has completed. */
1172         _PRELE(p);
1173 fail:
1174         PROC_UNLOCK(p);
1175         if (proctree_locked)
1176                 sx_xunlock(&proctree_lock);
1177         return (error);
1178 }
1179 #undef PROC_READ
1180 #undef PROC_WRITE
1181
1182 /*
1183  * Stop a process because of a debugging event;
1184  * stay stopped until p->p_step is cleared
1185  * (cleared by PIOCCONT in procfs).
1186  */
1187 void
1188 stopevent(struct proc *p, unsigned int event, unsigned int val)
1189 {
1190
1191         PROC_LOCK_ASSERT(p, MA_OWNED);
1192         p->p_step = 1;
1193         do {
1194                 p->p_xstat = val;
1195                 p->p_xthread = NULL;
1196                 p->p_stype = event;     /* Which event caused the stop? */
1197                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
1198                 msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1199         } while (p->p_step);
1200 }