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 #include <compat/freebsd32/freebsd32_signal.h>
  68
  69 struct ptrace_io_desc32 {
  70         int             piod_op;
  71         uint32_t        piod_offs;
  72         uint32_t        piod_addr;
  73         uint32_t        piod_len;
  74 };
  75
  76 struct ptrace_vm_entry32 {
  77         int             pve_entry;
  78         int             pve_timestamp;
  79         uint32_t        pve_start;
  80         uint32_t        pve_end;
  81         uint32_t        pve_offset;
  82         u_int           pve_prot;
  83         u_int           pve_pathlen;
  84         int32_t         pve_fileid;
  85         u_int           pve_fsid;
  86         uint32_t        pve_path;
  87 };
  88
  89 struct ptrace_lwpinfo32 {
  90         lwpid_t pl_lwpid;       /* LWP described. */
  91         int     pl_event;       /* Event that stopped the LWP. */
  92         int     pl_flags;       /* LWP flags. */
  93         sigset_t        pl_sigmask;     /* LWP signal mask */
  94         sigset_t        pl_siglist;     /* LWP pending signal */
  95         struct siginfo32 pl_siginfo;    /* siginfo for signal */
  96 };
  97
  98 #endif
  99
 100 /*
 101  * Functions implemented using PROC_ACTION():
 102  *
 103  * proc_read_regs(proc, regs)
 104  *      Get the current user-visible register set from the process
 105  *      and copy it into the regs structure (<machine/reg.h>).
 106  *      The process is stopped at the time read_regs is called.
 107  *
 108  * proc_write_regs(proc, regs)
 109  *      Update the current register set from the passed in regs
 110  *      structure.  Take care to avoid clobbering special CPU
 111  *      registers or privileged bits in the PSL.
 112  *      Depending on the architecture this may have fix-up work to do,
 113  *      especially if the IAR or PCW are modified.
 114  *      The process is stopped at the time write_regs is called.
 115  *
 116  * proc_read_fpregs, proc_write_fpregs
 117  *      deal with the floating point register set, otherwise as above.
 118  *
 119  * proc_read_dbregs, proc_write_dbregs
 120  *      deal with the processor debug register set, otherwise as above.
 121  *
 122  * proc_sstep(proc)
 123  *      Arrange for the process to trap after executing a single instruction.
 124  */
 125
 126 #define PROC_ACTION(action) do {                                        \
 127         int error;                                                      \
 128                                                                         \
 129         PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);                        \
 130         if ((td->td_proc->p_flag & P_INMEM) == 0)                       \
 131                 error = EIO;                                            \
 132         else                                                            \
 133                 error = (action);                                       \
 134         return (error);                                                 \
 135 } while(0)
 136
 137 int
 138 proc_read_regs(struct thread *td, struct reg *regs)
 139 {
 140
 141         PROC_ACTION(fill_regs(td, regs));
 142 }
 143
 144 int
 145 proc_write_regs(struct thread *td, struct reg *regs)
 146 {
 147
 148         PROC_ACTION(set_regs(td, regs));
 149 }
 150
 151 int
 152 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
 153 {
 154
 155         PROC_ACTION(fill_dbregs(td, dbregs));
 156 }
 157
 158 int
 159 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
 160 {
 161
 162         PROC_ACTION(set_dbregs(td, dbregs));
 163 }
 164
 165 /*
 166  * Ptrace doesn't support fpregs at all, and there are no security holes
 167  * or translations for fpregs, so we can just copy them.
 168  */
 169 int
 170 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
 171 {
 172
 173         PROC_ACTION(fill_fpregs(td, fpregs));
 174 }
 175
 176 int
 177 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
 178 {
 179
 180         PROC_ACTION(set_fpregs(td, fpregs));
 181 }
 182
 183 #ifdef COMPAT_FREEBSD32
 184 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
 185 int
 186 proc_read_regs32(struct thread *td, struct reg32 *regs32)
 187 {
 188
 189         PROC_ACTION(fill_regs32(td, regs32));
 190 }
 191
 192 int
 193 proc_write_regs32(struct thread *td, struct reg32 *regs32)
 194 {
 195
 196         PROC_ACTION(set_regs32(td, regs32));
 197 }
 198
 199 int
 200 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 201 {
 202
 203         PROC_ACTION(fill_dbregs32(td, dbregs32));
 204 }
 205
 206 int
 207 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
 208 {
 209
 210         PROC_ACTION(set_dbregs32(td, dbregs32));
 211 }
 212
 213 int
 214 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 215 {
 216
 217         PROC_ACTION(fill_fpregs32(td, fpregs32));
 218 }
 219
 220 int
 221 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
 222 {
 223
 224         PROC_ACTION(set_fpregs32(td, fpregs32));
 225 }
 226 #endif
 227
 228 int
 229 proc_sstep(struct thread *td)
 230 {
 231
 232         PROC_ACTION(ptrace_single_step(td));
 233 }
 234
 235 int
 236 proc_rwmem(struct proc *p, struct uio *uio)
 237 {
 238         vm_map_t map;
 239         vm_object_t backing_object, object;
 240         vm_offset_t pageno;             /* page number */
 241         vm_prot_t reqprot;
 242         int error, writing;
 243
 244         /*
 245          * Assert that someone has locked this vmspace.  (Should be
 246          * curthread but we can't assert that.)  This keeps the process
 247          * from exiting out from under us until this operation completes.
 248          */
 249         KASSERT(p->p_lock >= 1, ("%s: process %p (pid %d) not held", __func__,
 250             p, p->p_pid));
 251
 252         /*
 253          * The map we want...
 254          */
 255         map = &p->p_vmspace->vm_map;
 256
 257         writing = uio->uio_rw == UIO_WRITE;
 258         reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 259
 260         /*
 261          * Only map in one page at a time.  We don't have to, but it
 262          * makes things easier.  This way is trivial - right?
 263          */
 264         do {
 265                 vm_map_t tmap;
 266                 vm_offset_t uva;
 267                 int page_offset;                /* offset into page */
 268                 vm_map_entry_t out_entry;
 269                 vm_prot_t out_prot;
 270                 boolean_t wired;
 271                 vm_pindex_t pindex;
 272                 u_int len;
 273                 vm_page_t m;
 274
 275                 object = NULL;
 276
 277                 uva = (vm_offset_t)uio->uio_offset;
 278
 279                 /*
 280                  * Get the page number of this segment.
 281                  */
 282                 pageno = trunc_page(uva);
 283                 page_offset = uva - pageno;
 284
 285                 /*
 286                  * How many bytes to copy
 287                  */
 288                 len = min(PAGE_SIZE - page_offset, uio->uio_resid);
 289
 290                 /*
 291                  * Fault the page on behalf of the process
 292                  */
 293                 error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL);
 294                 if (error) {
 295                         if (error == KERN_RESOURCE_SHORTAGE)
 296                                 error = ENOMEM;
 297                         else
 298                                 error = EFAULT;
 299                         break;
 300                 }
 301
 302                 /*
 303                  * Now we need to get the page.  out_entry and wired
 304                  * aren't used.  One would think the vm code
 305                  * would be a *bit* nicer...  We use tmap because
 306                  * vm_map_lookup() can change the map argument.
 307                  */
 308                 tmap = map;
 309                 error = vm_map_lookup(&tmap, pageno, reqprot, &out_entry,
 310                     &object, &pindex, &out_prot, &wired);
 311                 if (error) {
 312                         error = EFAULT;
 313                         break;
 314                 }
 315                 VM_OBJECT_LOCK(object);
 316                 while ((m = vm_page_lookup(object, pindex)) == NULL &&
 317                     !writing &&
 318                     (backing_object = object->backing_object) != NULL) {
 319                         /*
 320                          * Allow fallback to backing objects if we are reading.
 321                          */
 322                         VM_OBJECT_LOCK(backing_object);
 323                         pindex += OFF_TO_IDX(object->backing_object_offset);
 324                         VM_OBJECT_UNLOCK(object);
 325                         object = backing_object;
 326                 }
 327                 if (writing && m != NULL) {
 328                         vm_page_dirty(m);
 329                         vm_pager_page_unswapped(m);
 330                 }
 331                 VM_OBJECT_UNLOCK(object);
 332                 if (m == NULL) {
 333                         vm_map_lookup_done(tmap, out_entry);
 334                         error = EFAULT;
 335                         break;
 336                 }
 337
 338                 /*
 339                  * Hold the page in memory.
 340                  */
 341                 vm_page_lock(m);
 342                 vm_page_hold(m);
 343                 vm_page_unlock(m);
 344
 345                 /*
 346                  * We're done with tmap now.
 347                  */
 348                 vm_map_lookup_done(tmap, out_entry);
 349
 350                 /*
 351                  * Now do the i/o move.
 352                  */
 353                 error = uiomove_fromphys(&m, page_offset, len, uio);
 354
 355                 /* Make the I-cache coherent for breakpoints. */
 356                 if (!error && writing && (out_prot & VM_PROT_EXECUTE))
 357                         vm_sync_icache(map, uva, len);
 358
 359                 /*
 360                  * Release the page.
 361                  */
 362                 vm_page_lock(m);
 363                 vm_page_unhold(m);
 364                 vm_page_unlock(m);
 365
 366         } while (error == 0 && uio->uio_resid > 0);
 367
 368         return (error);
 369 }
 370
 371 static int
 372 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
 373 {
 374         struct vattr vattr;
 375         vm_map_t map;
 376         vm_map_entry_t entry;
 377         vm_object_t obj, tobj, lobj;
 378         struct vmspace *vm;
 379         struct vnode *vp;
 380         char *freepath, *fullpath;
 381         u_int pathlen;
 382         int error, index, vfslocked;
 383
 384         error = 0;
 385         obj = NULL;
 386
 387         vm = vmspace_acquire_ref(p);
 388         map = &vm->vm_map;
 389         vm_map_lock_read(map);
 390
 391         do {
 392                 entry = map->header.next;
 393                 index = 0;
 394                 while (index < pve->pve_entry && entry != &map->header) {
 395                         entry = entry->next;
 396                         index++;
 397                 }
 398                 if (index != pve->pve_entry) {
 399                         error = EINVAL;
 400                         break;
 401                 }
 402                 while (entry != &map->header &&
 403                     (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
 404                         entry = entry->next;
 405                         index++;
 406                 }
 407                 if (entry == &map->header) {
 408                         error = ENOENT;
 409                         break;
 410                 }
 411
 412                 /* We got an entry. */
 413                 pve->pve_entry = index + 1;
 414                 pve->pve_timestamp = map->timestamp;
 415                 pve->pve_start = entry->start;
 416                 pve->pve_end = entry->end - 1;
 417                 pve->pve_offset = entry->offset;
 418                 pve->pve_prot = entry->protection;
 419
 420                 /* Backing object's path needed? */
 421                 if (pve->pve_pathlen == 0)
 422                         break;
 423
 424                 pathlen = pve->pve_pathlen;
 425                 pve->pve_pathlen = 0;
 426
 427                 obj = entry->object.vm_object;
 428                 if (obj != NULL)
 429                         VM_OBJECT_LOCK(obj);
 430         } while (0);
 431
 432         vm_map_unlock_read(map);
 433         vmspace_free(vm);
 434
 435         pve->pve_fsid = VNOVAL;
 436         pve->pve_fileid = VNOVAL;
 437
 438         if (error == 0 && obj != NULL) {
 439                 lobj = obj;
 440                 for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
 441                         if (tobj != obj)
 442                                 VM_OBJECT_LOCK(tobj);
 443                         if (lobj != obj)
 444                                 VM_OBJECT_UNLOCK(lobj);
 445                         lobj = tobj;
 446                         pve->pve_offset += tobj->backing_object_offset;
 447                 }
 448                 vp = (lobj->type == OBJT_VNODE) ? lobj->handle : NULL;
 449                 if (vp != NULL)
 450                         vref(vp);
 451                 if (lobj != obj)
 452                         VM_OBJECT_UNLOCK(lobj);
 453                 VM_OBJECT_UNLOCK(obj);
 454
 455                 if (vp != NULL) {
 456                         freepath = NULL;
 457                         fullpath = NULL;
 458                         vn_fullpath(td, vp, &fullpath, &freepath);
 459                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 460                         vn_lock(vp, LK_SHARED | LK_RETRY);
 461                         if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
 462                                 pve->pve_fileid = vattr.va_fileid;
 463                                 pve->pve_fsid = vattr.va_fsid;
 464                         }
 465                         vput(vp);
 466                         VFS_UNLOCK_GIANT(vfslocked);
 467
 468                         if (fullpath != NULL) {
 469                                 pve->pve_pathlen = strlen(fullpath) + 1;
 470                                 if (pve->pve_pathlen <= pathlen) {
 471                                         error = copyout(fullpath, pve->pve_path,
 472                                             pve->pve_pathlen);
 473                                 } else
 474                                         error = ENAMETOOLONG;
 475                         }
 476                         if (freepath != NULL)
 477                                 free(freepath, M_TEMP);
 478                 }
 479         }
 480
 481         return (error);
 482 }
 483
 484 #ifdef COMPAT_FREEBSD32
 485 static int
 486 ptrace_vm_entry32(struct thread *td, struct proc *p,
 487     struct ptrace_vm_entry32 *pve32)
 488 {
 489         struct ptrace_vm_entry pve;
 490         int error;
 491
 492         pve.pve_entry = pve32->pve_entry;
 493         pve.pve_pathlen = pve32->pve_pathlen;
 494         pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
 495
 496         error = ptrace_vm_entry(td, p, &pve);
 497         if (error == 0) {
 498                 pve32->pve_entry = pve.pve_entry;
 499                 pve32->pve_timestamp = pve.pve_timestamp;
 500                 pve32->pve_start = pve.pve_start;
 501                 pve32->pve_end = pve.pve_end;
 502                 pve32->pve_offset = pve.pve_offset;
 503                 pve32->pve_prot = pve.pve_prot;
 504                 pve32->pve_fileid = pve.pve_fileid;
 505                 pve32->pve_fsid = pve.pve_fsid;
 506         }
 507
 508         pve32->pve_pathlen = pve.pve_pathlen;
 509         return (error);
 510 }
 511
 512 static void
 513 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
 514     struct ptrace_lwpinfo32 *pl32)
 515 {
 516
 517         pl32->pl_lwpid = pl->pl_lwpid;
 518         pl32->pl_event = pl->pl_event;
 519         pl32->pl_flags = pl->pl_flags;
 520         pl32->pl_sigmask = pl->pl_sigmask;
 521         pl32->pl_siglist = pl->pl_siglist;
 522         siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
 523 }
 524 #endif /* COMPAT_FREEBSD32 */
 525
 526 /*
 527  * Process debugging system call.
 528  */
 529 #ifndef _SYS_SYSPROTO_H_
 530 struct ptrace_args {
 531         int     req;
 532         pid_t   pid;
 533         caddr_t addr;
 534         int     data;
 535 };
 536 #endif
 537
 538 #ifdef COMPAT_FREEBSD32
 539 /*
 540  * This CPP subterfuge is to try and reduce the number of ifdefs in
 541  * the body of the code.
 542  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
 543  * becomes either:
 544  *   copyin(uap->addr, &r.reg, sizeof r.reg);
 545  * or
 546  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
 547  * .. except this is done at runtime.
 548  */
 549 #define COPYIN(u, k, s)         wrap32 ? \
 550         copyin(u, k ## 32, s ## 32) : \
 551         copyin(u, k, s)
 552 #define COPYOUT(k, u, s)        wrap32 ? \
 553         copyout(k ## 32, u, s ## 32) : \
 554         copyout(k, u, s)
 555 #else
 556 #define COPYIN(u, k, s)         copyin(u, k, s)
 557 #define COPYOUT(k, u, s)        copyout(k, u, s)
 558 #endif
 559 int
 560 ptrace(struct thread *td, struct ptrace_args *uap)
 561 {
 562         /*
 563          * XXX this obfuscation is to reduce stack usage, but the register
 564          * structs may be too large to put on the stack anyway.
 565          */
 566         union {
 567                 struct ptrace_io_desc piod;
 568                 struct ptrace_lwpinfo pl;
 569                 struct ptrace_vm_entry pve;
 570                 struct dbreg dbreg;
 571                 struct fpreg fpreg;
 572                 struct reg reg;
 573 #ifdef COMPAT_FREEBSD32
 574                 struct dbreg32 dbreg32;
 575                 struct fpreg32 fpreg32;
 576                 struct reg32 reg32;
 577                 struct ptrace_io_desc32 piod32;
 578                 struct ptrace_lwpinfo32 pl32;
 579                 struct ptrace_vm_entry32 pve32;
 580 #endif
 581         } r;
 582         void *addr;
 583         int error = 0;
 584 #ifdef COMPAT_FREEBSD32
 585         int wrap32 = 0;
 586
 587         if (SV_CURPROC_FLAG(SV_ILP32))
 588                 wrap32 = 1;
 589 #endif
 590         AUDIT_ARG_PID(uap->pid);
 591         AUDIT_ARG_CMD(uap->req);
 592         AUDIT_ARG_VALUE(uap->data);
 593         addr = &r;
 594         switch (uap->req) {
 595         case PT_GETREGS:
 596         case PT_GETFPREGS:
 597         case PT_GETDBREGS:
 598         case PT_LWPINFO:
 599                 break;
 600         case PT_SETREGS:
 601                 error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
 602                 break;
 603         case PT_SETFPREGS:
 604                 error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
 605                 break;
 606         case PT_SETDBREGS:
 607                 error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
 608                 break;
 609         case PT_IO:
 610                 error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
 611                 break;
 612         case PT_VM_ENTRY:
 613                 error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
 614                 break;
 615         default:
 616                 addr = uap->addr;
 617                 break;
 618         }
 619         if (error)
 620                 return (error);
 621
 622         error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
 623         if (error)
 624                 return (error);
 625
 626         switch (uap->req) {
 627         case PT_VM_ENTRY:
 628                 error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
 629                 break;
 630         case PT_IO:
 631                 error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
 632                 break;
 633         case PT_GETREGS:
 634                 error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
 635                 break;
 636         case PT_GETFPREGS:
 637                 error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
 638                 break;
 639         case PT_GETDBREGS:
 640                 error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
 641                 break;
 642         case PT_LWPINFO:
 643                 error = copyout(&r.pl, uap->addr, uap->data);
 644                 break;
 645         }
 646
 647         return (error);
 648 }
 649 #undef COPYIN
 650 #undef COPYOUT
 651
 652 #ifdef COMPAT_FREEBSD32
 653 /*
 654  *   PROC_READ(regs, td2, addr);
 655  * becomes either:
 656  *   proc_read_regs(td2, addr);
 657  * or
 658  *   proc_read_regs32(td2, addr);
 659  * .. except this is done at runtime.  There is an additional
 660  * complication in that PROC_WRITE disallows 32 bit consumers
 661  * from writing to 64 bit address space targets.
 662  */
 663 #define PROC_READ(w, t, a)      wrap32 ? \
 664         proc_read_ ## w ## 32(t, a) : \
 665         proc_read_ ## w (t, a)
 666 #define PROC_WRITE(w, t, a)     wrap32 ? \
 667         (safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
 668         proc_write_ ## w (t, a)
 669 #else
 670 #define PROC_READ(w, t, a)      proc_read_ ## w (t, a)
 671 #define PROC_WRITE(w, t, a)     proc_write_ ## w (t, a)
 672 #endif
 673
 674 int
 675 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 676 {
 677         struct iovec iov;
 678         struct uio uio;
 679         struct proc *curp, *p, *pp;
 680         struct thread *td2 = NULL;
 681         struct ptrace_io_desc *piod = NULL;
 682         struct ptrace_lwpinfo *pl;
 683         int error, write, tmp, num;
 684         int proctree_locked = 0;
 685         lwpid_t tid = 0, *buf;
 686 #ifdef COMPAT_FREEBSD32
 687         int wrap32 = 0, safe = 0;
 688         struct ptrace_io_desc32 *piod32 = NULL;
 689         struct ptrace_lwpinfo32 *pl32 = NULL;
 690         struct ptrace_lwpinfo plr;
 691 #endif
 692
 693         curp = td->td_proc;
 694
 695         /* Lock proctree before locking the process. */
 696         switch (req) {
 697         case PT_TRACE_ME:
 698         case PT_ATTACH:
 699         case PT_STEP:
 700         case PT_CONTINUE:
 701         case PT_TO_SCE:
 702         case PT_TO_SCX:
 703         case PT_SYSCALL:
 704         case PT_DETACH:
 705                 sx_xlock(&proctree_lock);
 706                 proctree_locked = 1;
 707                 break;
 708         default:
 709                 break;
 710         }
 711
 712         write = 0;
 713         if (req == PT_TRACE_ME) {
 714                 p = td->td_proc;
 715                 PROC_LOCK(p);
 716         } else {
 717                 if (pid <= PID_MAX) {
 718                         if ((p = pfind(pid)) == NULL) {
 719                                 if (proctree_locked)
 720                                         sx_xunlock(&proctree_lock);
 721                                 return (ESRCH);
 722                         }
 723                 } else {
 724                         td2 = tdfind(pid, -1);
 725                         if (td2 == NULL) {
 726                                 if (proctree_locked)
 727                                         sx_xunlock(&proctree_lock);
 728                                 return (ESRCH);
 729                         }
 730                         p = td2->td_proc;
 731                         tid = pid;
 732                         pid = p->p_pid;
 733                 }
 734         }
 735         AUDIT_ARG_PROCESS(p);
 736
 737         if ((p->p_flag & P_WEXIT) != 0) {
 738                 error = ESRCH;
 739                 goto fail;
 740         }
 741         if ((error = p_cansee(td, p)) != 0)
 742                 goto fail;
 743
 744         if ((error = p_candebug(td, p)) != 0)
 745                 goto fail;
 746
 747         /*
 748          * System processes can't be debugged.
 749          */
 750         if ((p->p_flag & P_SYSTEM) != 0) {
 751                 error = EINVAL;
 752                 goto fail;
 753         }
 754
 755         if (tid == 0) {
 756                 if ((p->p_flag & P_STOPPED_TRACE) != 0) {
 757                         KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
 758                         td2 = p->p_xthread;
 759                 } else {
 760                         td2 = FIRST_THREAD_IN_PROC(p);
 761                 }
 762                 tid = td2->td_tid;
 763         }
 764
 765 #ifdef COMPAT_FREEBSD32
 766         /*
 767          * Test if we're a 32 bit client and what the target is.
 768          * Set the wrap controls accordingly.
 769          */
 770         if (SV_CURPROC_FLAG(SV_ILP32)) {
 771                 if (td2->td_proc->p_sysent->sv_flags & SV_ILP32)
 772                         safe = 1;
 773                 wrap32 = 1;
 774         }
 775 #endif
 776         /*
 777          * Permissions check
 778          */
 779         switch (req) {
 780         case PT_TRACE_ME:
 781                 /* Always legal. */
 782                 break;
 783
 784         case PT_ATTACH:
 785                 /* Self */
 786                 if (p->p_pid == td->td_proc->p_pid) {
 787                         error = EINVAL;
 788                         goto fail;
 789                 }
 790
 791                 /* Already traced */
 792                 if (p->p_flag & P_TRACED) {
 793                         error = EBUSY;
 794                         goto fail;
 795                 }
 796
 797                 /* Can't trace an ancestor if you're being traced. */
 798                 if (curp->p_flag & P_TRACED) {
 799                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
 800                                 if (pp == p) {
 801                                         error = EINVAL;
 802                                         goto fail;
 803                                 }
 804                         }
 805                 }
 806
 807
 808                 /* OK */
 809                 break;
 810
 811         case PT_CLEARSTEP:
 812                 /* Allow thread to clear single step for itself */
 813                 if (td->td_tid == tid)
 814                         break;
 815
 816                 /* FALLTHROUGH */
 817         default:
 818                 /* not being traced... */
 819                 if ((p->p_flag & P_TRACED) == 0) {
 820                         error = EPERM;
 821                         goto fail;
 822                 }
 823
 824                 /* not being traced by YOU */
 825                 if (p->p_pptr != td->td_proc) {
 826                         error = EBUSY;
 827                         goto fail;
 828                 }
 829
 830                 /* not currently stopped */
 831                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
 832                     p->p_suspcount != p->p_numthreads  ||
 833                     (p->p_flag & P_WAITED) == 0) {
 834                         error = EBUSY;
 835                         goto fail;
 836                 }
 837
 838                 if ((p->p_flag & P_STOPPED_TRACE) == 0) {
 839                         static int count = 0;
 840                         if (count++ == 0)
 841                                 printf("P_STOPPED_TRACE not set.\n");
 842                 }
 843
 844                 /* OK */
 845                 break;
 846         }
 847
 848         /* Keep this process around until we finish this request. */
 849         _PHOLD(p);
 850
 851 #ifdef FIX_SSTEP
 852         /*
 853          * Single step fixup ala procfs
 854          */
 855         FIX_SSTEP(td2);
 856 #endif
 857
 858         /*
 859          * Actually do the requests
 860          */
 861
 862         td->td_retval[0] = 0;
 863
 864         switch (req) {
 865         case PT_TRACE_ME:
 866                 /* set my trace flag and "owner" so it can read/write me */
 867                 p->p_flag |= P_TRACED;
 868                 p->p_oppid = p->p_pptr->p_pid;
 869                 break;
 870
 871         case PT_ATTACH:
 872                 /* security check done above */
 873                 p->p_flag |= P_TRACED;
 874                 p->p_oppid = p->p_pptr->p_pid;
 875                 if (p->p_pptr != td->td_proc)
 876                         proc_reparent(p, td->td_proc);
 877                 data = SIGSTOP;
 878                 goto sendsig;   /* in PT_CONTINUE below */
 879
 880         case PT_CLEARSTEP:
 881                 error = ptrace_clear_single_step(td2);
 882                 break;
 883
 884         case PT_SETSTEP:
 885                 error = ptrace_single_step(td2);
 886                 break;
 887
 888         case PT_SUSPEND:
 889                 td2->td_dbgflags |= TDB_SUSPEND;
 890                 thread_lock(td2);
 891                 td2->td_flags |= TDF_NEEDSUSPCHK;
 892                 thread_unlock(td2);
 893                 break;
 894
 895         case PT_RESUME:
 896                 td2->td_dbgflags &= ~TDB_SUSPEND;
 897                 break;
 898
 899         case PT_STEP:
 900         case PT_CONTINUE:
 901         case PT_TO_SCE:
 902         case PT_TO_SCX:
 903         case PT_SYSCALL:
 904         case PT_DETACH:
 905                 /* Zero means do not send any signal */
 906                 if (data < 0 || data > _SIG_MAXSIG) {
 907                         error = EINVAL;
 908                         break;
 909                 }
 910
 911                 switch (req) {
 912                 case PT_STEP:
 913                         error = ptrace_single_step(td2);
 914                         if (error)
 915                                 goto out;
 916                         break;
 917                 case PT_CONTINUE:
 918                 case PT_TO_SCE:
 919                 case PT_TO_SCX:
 920                 case PT_SYSCALL:
 921                         if (addr != (void *)1) {
 922                                 error = ptrace_set_pc(td2,
 923                                     (u_long)(uintfptr_t)addr);
 924                                 if (error)
 925                                         goto out;
 926                         }
 927                         switch (req) {
 928                         case PT_TO_SCE:
 929                                 p->p_stops |= S_PT_SCE;
 930                                 break;
 931                         case PT_TO_SCX:
 932                                 p->p_stops |= S_PT_SCX;
 933                                 break;
 934                         case PT_SYSCALL:
 935                                 p->p_stops |= S_PT_SCE | S_PT_SCX;
 936                                 break;
 937                         }
 938                         break;
 939                 case PT_DETACH:
 940                         /* reset process parent */
 941                         if (p->p_oppid != p->p_pptr->p_pid) {
 942                                 struct proc *pp;
 943
 944                                 PROC_LOCK(p->p_pptr);
 945                                 sigqueue_take(p->p_ksi);
 946                                 PROC_UNLOCK(p->p_pptr);
 947
 948                                 PROC_UNLOCK(p);
 949                                 pp = pfind(p->p_oppid);
 950                                 if (pp == NULL)
 951                                         pp = initproc;
 952                                 else
 953                                         PROC_UNLOCK(pp);
 954                                 PROC_LOCK(p);
 955                                 proc_reparent(p, pp);
 956                                 if (pp == initproc)
 957                                         p->p_sigparent = SIGCHLD;
 958                         }
 959                         p->p_flag &= ~(P_TRACED | P_WAITED);
 960                         p->p_oppid = 0;
 961
 962                         /* should we send SIGCHLD? */
 963                         /* childproc_continued(p); */
 964                         break;
 965                 }
 966
 967         sendsig:
 968                 if (proctree_locked) {
 969                         sx_xunlock(&proctree_lock);
 970                         proctree_locked = 0;
 971                 }
 972                 p->p_xstat = data;
 973                 p->p_xthread = NULL;
 974                 if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
 975                         /* deliver or queue signal */
 976                         td2->td_dbgflags &= ~TDB_XSIG;
 977                         td2->td_xsig = data;
 978
 979                         if (req == PT_DETACH) {
 980                                 struct thread *td3;
 981                                 FOREACH_THREAD_IN_PROC(p, td3) {
 982                                         td3->td_dbgflags &= ~TDB_SUSPEND;
 983                                 }
 984                         }
 985                         /*
 986                          * unsuspend all threads, to not let a thread run,
 987                          * you should use PT_SUSPEND to suspend it before
 988                          * continuing process.
 989                          */
 990                         PROC_SLOCK(p);
 991                         p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
 992                         thread_unsuspend(p);
 993                         PROC_SUNLOCK(p);
 994                 } else {
 995                         if (data)
 996                                 psignal(p, data);
 997                 }
 998                 break;
 999
1000         case PT_WRITE_I:
1001         case PT_WRITE_D:
1002                 td2->td_dbgflags |= TDB_USERWR;
1003                 write = 1;
1004                 /* FALLTHROUGH */
1005         case PT_READ_I:
1006         case PT_READ_D:
1007                 PROC_UNLOCK(p);
1008                 tmp = 0;
1009                 /* write = 0 set above */
1010                 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
1011                 iov.iov_len = sizeof(int);
1012                 uio.uio_iov = &iov;
1013                 uio.uio_iovcnt = 1;
1014                 uio.uio_offset = (off_t)(uintptr_t)addr;
1015                 uio.uio_resid = sizeof(int);
1016                 uio.uio_segflg = UIO_SYSSPACE;  /* i.e.: the uap */
1017                 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
1018                 uio.uio_td = td;
1019                 error = proc_rwmem(p, &uio);
1020                 if (uio.uio_resid != 0) {
1021                         /*
1022                          * XXX proc_rwmem() doesn't currently return ENOSPC,
1023                          * so I think write() can bogusly return 0.
1024                          * XXX what happens for short writes?  We don't want
1025                          * to write partial data.
1026                          * XXX proc_rwmem() returns EPERM for other invalid
1027                          * addresses.  Convert this to EINVAL.  Does this
1028                          * clobber returns of EPERM for other reasons?
1029                          */
1030                         if (error == 0 || error == ENOSPC || error == EPERM)
1031                                 error = EINVAL; /* EOF */
1032                 }
1033                 if (!write)
1034                         td->td_retval[0] = tmp;
1035                 PROC_LOCK(p);
1036                 break;
1037
1038         case PT_IO:
1039 #ifdef COMPAT_FREEBSD32
1040                 if (wrap32) {
1041                         piod32 = addr;
1042                         iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1043                         iov.iov_len = piod32->piod_len;
1044                         uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1045                         uio.uio_resid = piod32->piod_len;
1046                 } else
1047 #endif
1048                 {
1049                         piod = addr;
1050                         iov.iov_base = piod->piod_addr;
1051                         iov.iov_len = piod->piod_len;
1052                         uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1053                         uio.uio_resid = piod->piod_len;
1054                 }
1055                 uio.uio_iov = &iov;
1056                 uio.uio_iovcnt = 1;
1057                 uio.uio_segflg = UIO_USERSPACE;
1058                 uio.uio_td = td;
1059 #ifdef COMPAT_FREEBSD32
1060                 tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1061 #else
1062                 tmp = piod->piod_op;
1063 #endif
1064                 switch (tmp) {
1065                 case PIOD_READ_D:
1066                 case PIOD_READ_I:
1067                         uio.uio_rw = UIO_READ;
1068                         break;
1069                 case PIOD_WRITE_D:
1070                 case PIOD_WRITE_I:
1071                         td2->td_dbgflags |= TDB_USERWR;
1072                         uio.uio_rw = UIO_WRITE;
1073                         break;
1074                 default:
1075                         error = EINVAL;
1076                         goto out;
1077                 }
1078                 PROC_UNLOCK(p);
1079                 error = proc_rwmem(p, &uio);
1080 #ifdef COMPAT_FREEBSD32
1081                 if (wrap32)
1082                         piod32->piod_len -= uio.uio_resid;
1083                 else
1084 #endif
1085                         piod->piod_len -= uio.uio_resid;
1086                 PROC_LOCK(p);
1087                 break;
1088
1089         case PT_KILL:
1090                 data = SIGKILL;
1091                 goto sendsig;   /* in PT_CONTINUE above */
1092
1093         case PT_SETREGS:
1094                 td2->td_dbgflags |= TDB_USERWR;
1095                 error = PROC_WRITE(regs, td2, addr);
1096                 break;
1097
1098         case PT_GETREGS:
1099                 error = PROC_READ(regs, td2, addr);
1100                 break;
1101
1102         case PT_SETFPREGS:
1103                 td2->td_dbgflags |= TDB_USERWR;
1104                 error = PROC_WRITE(fpregs, td2, addr);
1105                 break;
1106
1107         case PT_GETFPREGS:
1108                 error = PROC_READ(fpregs, td2, addr);
1109                 break;
1110
1111         case PT_SETDBREGS:
1112                 td2->td_dbgflags |= TDB_USERWR;
1113                 error = PROC_WRITE(dbregs, td2, addr);
1114                 break;
1115
1116         case PT_GETDBREGS:
1117                 error = PROC_READ(dbregs, td2, addr);
1118                 break;
1119
1120         case PT_LWPINFO:
1121                 if (data <= 0 ||
1122 #ifdef COMPAT_FREEBSD32
1123                     (!wrap32 && data > sizeof(*pl)) ||
1124                     (wrap32 && data > sizeof(*pl32))) {
1125 #else
1126                     data > sizeof(*pl)) {
1127 #endif
1128                         error = EINVAL;
1129                         break;
1130                 }
1131 #ifdef COMPAT_FREEBSD32
1132                 if (wrap32) {
1133                         pl = &plr;
1134                         pl32 = addr;
1135                 } else
1136 #endif
1137                 pl = addr;
1138                 pl->pl_lwpid = td2->td_tid;
1139                 pl->pl_flags = 0;
1140                 if (td2->td_dbgflags & TDB_XSIG) {
1141                         pl->pl_event = PL_EVENT_SIGNAL;
1142                         if (td2->td_dbgksi.ksi_signo != 0 &&
1143 #ifdef COMPAT_FREEBSD32
1144                             ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1145                             pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1146                             (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1147                             pl_siginfo) + sizeof(struct siginfo32)))
1148 #else
1149                             data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1150                             + sizeof(pl->pl_siginfo)
1151 #endif
1152                         ){
1153                                 pl->pl_flags |= PL_FLAG_SI;
1154                                 pl->pl_siginfo = td2->td_dbgksi.ksi_info;
1155                         }
1156                 }
1157                 if ((pl->pl_flags & PL_FLAG_SI) == 0)
1158                         bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
1159                 if (td2->td_dbgflags & TDB_SCE)
1160                         pl->pl_flags |= PL_FLAG_SCE;
1161                 else if (td2->td_dbgflags & TDB_SCX)
1162                         pl->pl_flags |= PL_FLAG_SCX;
1163                 if (td2->td_dbgflags & TDB_EXEC)
1164                         pl->pl_flags |= PL_FLAG_EXEC;
1165                 pl->pl_sigmask = td2->td_sigmask;
1166                 pl->pl_siglist = td2->td_siglist;
1167 #ifdef COMPAT_FREEBSD32
1168                 if (wrap32)
1169                         ptrace_lwpinfo_to32(pl, pl32);
1170 #endif
1171                 break;
1172
1173         case PT_GETNUMLWPS:
1174                 td->td_retval[0] = p->p_numthreads;
1175                 break;
1176
1177         case PT_GETLWPLIST:
1178                 if (data <= 0) {
1179                         error = EINVAL;
1180                         break;
1181                 }
1182                 num = imin(p->p_numthreads, data);
1183                 PROC_UNLOCK(p);
1184                 buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1185                 tmp = 0;
1186                 PROC_LOCK(p);
1187                 FOREACH_THREAD_IN_PROC(p, td2) {
1188                         if (tmp >= num)
1189                                 break;
1190                         buf[tmp++] = td2->td_tid;
1191                 }
1192                 PROC_UNLOCK(p);
1193                 error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1194                 free(buf, M_TEMP);
1195                 if (!error)
1196                         td->td_retval[0] = tmp;
1197                 PROC_LOCK(p);
1198                 break;
1199
1200         case PT_VM_TIMESTAMP:
1201                 td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1202                 break;
1203
1204         case PT_VM_ENTRY:
1205                 PROC_UNLOCK(p);
1206 #ifdef COMPAT_FREEBSD32
1207                 if (wrap32)
1208                         error = ptrace_vm_entry32(td, p, addr);
1209                 else
1210 #endif
1211                 error = ptrace_vm_entry(td, p, addr);
1212                 PROC_LOCK(p);
1213                 break;
1214
1215         default:
1216 #ifdef __HAVE_PTRACE_MACHDEP
1217                 if (req >= PT_FIRSTMACH) {
1218                         PROC_UNLOCK(p);
1219                         error = cpu_ptrace(td2, req, addr, data);
1220                         PROC_LOCK(p);
1221                 } else
1222 #endif
1223                         /* Unknown request. */
1224                         error = EINVAL;
1225                 break;
1226         }
1227
1228 out:
1229         /* Drop our hold on this process now that the request has completed. */
1230         _PRELE(p);
1231 fail:
1232         PROC_UNLOCK(p);
1233         if (proctree_locked)
1234                 sx_xunlock(&proctree_lock);
1235         return (error);
1236 }
1237 #undef PROC_READ
1238 #undef PROC_WRITE
1239
1240 /*
1241  * Stop a process because of a debugging event;
1242  * stay stopped until p->p_step is cleared
1243  * (cleared by PIOCCONT in procfs).
1244  */
1245 void
1246 stopevent(struct proc *p, unsigned int event, unsigned int val)
1247 {
1248
1249         PROC_LOCK_ASSERT(p, MA_OWNED);
1250         p->p_step = 1;
1251         do {
1252                 p->p_xstat = val;
1253                 p->p_xthread = NULL;
1254                 p->p_stype = event;     /* Which event caused the stop? */
1255                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
1256                 msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1257         } while (p->p_step);
1258 }