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