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  * $FreeBSD: src/sys/kern/sys_process.c,v 1.51.2.6 2003/01/08 03:06:45 kan Exp $
  32  * $DragonFly: src/sys/kern/sys_process.c,v 1.19 2005/11/21 21:59:50 dillon Exp $
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/sysproto.h>
  38 #include <sys/proc.h>
  39 #include <sys/vnode.h>
  40 #include <sys/ptrace.h>
  41
  42 #include <machine/reg.h>
  43 #include <vm/vm.h>
  44 #include <sys/lock.h>
  45 #include <vm/pmap.h>
  46 #include <vm/vm_map.h>
  47 #include <vm/vm_page.h>
  48
  49 #include <sys/user.h>
  50 #include <vfs/procfs/procfs.h>
  51 #include <sys/thread2.h>
  52
  53 /* use the equivalent procfs code */
  54 #if 0
  55 static int
  56 pread (struct proc *procp, unsigned int addr, unsigned int *retval) {
  57         int             rv;
  58         vm_map_t        map, tmap;
  59         vm_object_t     object;
  60         vm_offset_t     kva = 0;
  61         int             page_offset;    /* offset into page */
  62         vm_offset_t     pageno;         /* page number */
  63         vm_map_entry_t  out_entry;
  64         vm_prot_t       out_prot;
  65         boolean_t       wired;
  66         vm_pindex_t     pindex;
  67
  68         /* Map page into kernel space */
  69
  70         map = &procp->p_vmspace->vm_map;
  71
  72         page_offset = addr - trunc_page(addr);
  73         pageno = trunc_page(addr);
  74
  75         tmap = map;
  76         rv = vm_map_lookup (&tmap, pageno, VM_PROT_READ, &out_entry,
  77                 &object, &pindex, &out_prot, &wired);
  78
  79         if (rv != KERN_SUCCESS)
  80                 return EINVAL;
  81
  82         vm_map_lookup_done (tmap, out_entry, 0);
  83
  84         /* Find space in kernel_map for the page we're interested in */
  85         rv = vm_map_find (kernel_map, object, IDX_TO_OFF(pindex),
  86                 &kva, PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0);
  87
  88         if (!rv) {
  89                 vm_object_reference (object);
  90
  91                 rv = vm_map_wire (kernel_map, kva, kva + PAGE_SIZE, 0);
  92                 if (!rv) {
  93                         *retval = 0;
  94                         bcopy ((caddr_t)kva + page_offset,
  95                                retval, sizeof *retval);
  96                 }
  97                 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE);
  98         }
  99
 100         return rv;
 101 }
 102
 103 static int
 104 pwrite (struct proc *procp, unsigned int addr, unsigned int datum) {
 105         int             rv;
 106         vm_map_t        map, tmap;
 107         vm_object_t     object;
 108         vm_offset_t     kva = 0;
 109         int             page_offset;    /* offset into page */
 110         vm_offset_t     pageno;         /* page number */
 111         vm_map_entry_t  out_entry;
 112         vm_prot_t       out_prot;
 113         boolean_t       wired;
 114         vm_pindex_t     pindex;
 115         boolean_t       fix_prot = 0;
 116
 117         /* Map page into kernel space */
 118
 119         map = &procp->p_vmspace->vm_map;
 120
 121         page_offset = addr - trunc_page(addr);
 122         pageno = trunc_page(addr);
 123
 124         /*
 125          * Check the permissions for the area we're interested in.
 126          */
 127
 128         if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE,
 129                 VM_PROT_WRITE) == FALSE) {
 130                 /*
 131                  * If the page was not writable, we make it so.
 132                  * XXX It is possible a page may *not* be read/executable,
 133                  * if a process changes that!
 134                  */
 135                 fix_prot = 1;
 136                 /* The page isn't writable, so let's try making it so... */
 137                 if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE,
 138                         VM_PROT_ALL, 0)) != KERN_SUCCESS)
 139                   return EFAULT;        /* I guess... */
 140         }
 141
 142         /*
 143          * Now we need to get the page.  out_entry, out_prot, wired, and
 144          * single_use aren't used.  One would think the vm code would be
 145          * a *bit* nicer...  We use tmap because vm_map_lookup() can
 146          * change the map argument.
 147          */
 148
 149         tmap = map;
 150         rv = vm_map_lookup (&tmap, pageno, VM_PROT_WRITE, &out_entry,
 151                 &object, &pindex, &out_prot, &wired);
 152         if (rv != KERN_SUCCESS) {
 153                 return EINVAL;
 154         }
 155
 156         /*
 157          * Okay, we've got the page.  Let's release tmap.
 158          */
 159
 160         vm_map_lookup_done (tmap, out_entry, 0);
 161
 162         /*
 163          * Fault the page in...
 164          */
 165
 166         rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE);
 167         if (rv != KERN_SUCCESS)
 168                 return EFAULT;
 169
 170         /* Find space in kernel_map for the page we're interested in */
 171         rv = vm_map_find (kernel_map, object, IDX_TO_OFF(pindex),
 172                 &kva, PAGE_SIZE, 0,
 173                 VM_PROT_ALL, VM_PROT_ALL, 0);
 174         if (!rv) {
 175                 vm_object_reference (object);
 176
 177                 rv = vm_map_wire (kernel_map, kva, kva + PAGE_SIZE, 0);
 178                 if (!rv) {
 179                   bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum);
 180                 }
 181                 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE);
 182         }
 183
 184         if (fix_prot)
 185                 vm_map_protect (map, pageno, pageno + PAGE_SIZE,
 186                         VM_PROT_READ|VM_PROT_EXECUTE, 0);
 187         return rv;
 188 }
 189 #endif
 190
 191 /*
 192  * Process debugging system call.
 193  */
 194 int
 195 ptrace(struct ptrace_args *uap)
 196 {
 197         struct proc *p = curproc;
 198
 199         /*
 200          * XXX this obfuscation is to reduce stack usage, but the register
 201          * structs may be too large to put on the stack anyway.
 202          */
 203         union {
 204                 struct ptrace_io_desc piod;
 205                 struct dbreg dbreg;
 206                 struct fpreg fpreg;
 207                 struct reg reg;
 208         } r;
 209         void *addr;
 210         int error = 0;
 211
 212         addr = &r;
 213         switch (uap->req) {
 214         case PT_GETREGS:
 215         case PT_GETFPREGS:
 216 #ifdef PT_GETDBREGS
 217         case PT_GETDBREGS:
 218 #endif
 219                 break;
 220         case PT_SETREGS:
 221                 error = copyin(uap->addr, &r.reg, sizeof r.reg);
 222                 break;
 223         case PT_SETFPREGS:
 224                 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg);
 225                 break;
 226 #ifdef PT_SETDBREGS
 227         case PT_SETDBREGS:
 228                 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg);
 229                 break;
 230 #endif
 231         case PT_IO:
 232                 error = copyin(uap->addr, &r.piod, sizeof r.piod);
 233                 break;
 234         default:
 235                 addr = uap->addr;
 236         }
 237         if (error)
 238                 return (error);
 239
 240         error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data,
 241                         &uap->sysmsg_result);
 242         if (error)
 243                 return (error);
 244
 245         switch (uap->req) {
 246         case PT_IO:
 247                 (void)copyout(&r.piod, uap->addr, sizeof r.piod);
 248                 break;
 249         case PT_GETREGS:
 250                 error = copyout(&r.reg, uap->addr, sizeof r.reg);
 251                 break;
 252         case PT_GETFPREGS:
 253                 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg);
 254                 break;
 255 #ifdef PT_GETDBREGS
 256         case PT_GETDBREGS:
 257                 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg);
 258                 break;
 259 #endif
 260         }
 261
 262         return (error);
 263 }
 264
 265 int
 266 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr, int data, int *res)
 267 {
 268         struct proc *p, *pp;
 269         struct iovec iov;
 270         struct uio uio;
 271         struct ptrace_io_desc *piod;
 272         int error = 0;
 273         int write, tmp;
 274
 275         write = 0;
 276         if (req == PT_TRACE_ME) {
 277                 p = curp;
 278         } else {
 279                 if ((p = pfind(pid)) == NULL)
 280                         return ESRCH;
 281         }
 282         if (!PRISON_CHECK(curp->p_ucred, p->p_ucred))
 283                 return (ESRCH);
 284
 285         /* Can't trace a process that's currently exec'ing. */
 286         if ((p->p_flag & P_INEXEC) != 0)
 287                 return EAGAIN;
 288
 289         /*
 290          * Permissions check
 291          */
 292         switch (req) {
 293         case PT_TRACE_ME:
 294                 /* Always legal. */
 295                 break;
 296
 297         case PT_ATTACH:
 298                 /* Self */
 299                 if (p->p_pid == curp->p_pid)
 300                         return EINVAL;
 301
 302                 /* Already traced */
 303                 if (p->p_flag & P_TRACED)
 304                         return EBUSY;
 305
 306                 if (curp->p_flag & P_TRACED)
 307                         for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr)
 308                                 if (pp == p)
 309                                         return (EINVAL);
 310
 311                 /* not owned by you, has done setuid (unless you're root) */
 312                 if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) ||
 313                      (p->p_flag & P_SUGID)) {
 314                         if ((error = suser(curp->p_thread)) != 0)
 315                                 return error;
 316                 }
 317
 318                 /* can't trace init when securelevel > 0 */
 319                 if (securelevel > 0 && p->p_pid == 1)
 320                         return EPERM;
 321
 322                 /* OK */
 323                 break;
 324
 325         case PT_READ_I:
 326         case PT_READ_D:
 327         case PT_WRITE_I:
 328         case PT_WRITE_D:
 329         case PT_IO:
 330         case PT_CONTINUE:
 331         case PT_KILL:
 332         case PT_STEP:
 333         case PT_DETACH:
 334 #ifdef PT_GETREGS
 335         case PT_GETREGS:
 336 #endif
 337 #ifdef PT_SETREGS
 338         case PT_SETREGS:
 339 #endif
 340 #ifdef PT_GETFPREGS
 341         case PT_GETFPREGS:
 342 #endif
 343 #ifdef PT_SETFPREGS
 344         case PT_SETFPREGS:
 345 #endif
 346 #ifdef PT_GETDBREGS
 347         case PT_GETDBREGS:
 348 #endif
 349 #ifdef PT_SETDBREGS
 350         case PT_SETDBREGS:
 351 #endif
 352                 /* not being traced... */
 353                 if ((p->p_flag & P_TRACED) == 0)
 354                         return EPERM;
 355
 356                 /* not being traced by YOU */
 357                 if (p->p_pptr != curp)
 358                         return EBUSY;
 359
 360                 /* not currently stopped */
 361                 if ((p->p_flag & P_STOPPED) == 0 ||
 362                     (p->p_flag & P_WAITED) == 0) {
 363                         return EBUSY;
 364                 }
 365
 366                 /* OK */
 367                 break;
 368
 369         default:
 370                 return EINVAL;
 371         }
 372
 373 #ifdef FIX_SSTEP
 374         /*
 375          * Single step fixup ala procfs
 376          */
 377         FIX_SSTEP(p);
 378 #endif
 379
 380         /*
 381          * Actually do the requests
 382          */
 383
 384         *res = 0;
 385
 386         switch (req) {
 387         case PT_TRACE_ME:
 388                 /* set my trace flag and "owner" so it can read/write me */
 389                 p->p_flag |= P_TRACED;
 390                 p->p_oppid = p->p_pptr->p_pid;
 391                 return 0;
 392
 393         case PT_ATTACH:
 394                 /* security check done above */
 395                 p->p_flag |= P_TRACED;
 396                 p->p_oppid = p->p_pptr->p_pid;
 397                 if (p->p_pptr != curp)
 398                         proc_reparent(p, curp);
 399                 data = SIGSTOP;
 400                 goto sendsig;   /* in PT_CONTINUE below */
 401
 402         case PT_STEP:
 403         case PT_CONTINUE:
 404         case PT_DETACH:
 405                 /* Zero means do not send any signal */
 406                 if (data < 0 || data > _SIG_MAXSIG)
 407                         return EINVAL;
 408
 409                 PHOLD(p);
 410
 411                 if (req == PT_STEP) {
 412                         if ((error = ptrace_single_step (&p->p_lwp))) {
 413                                 PRELE(p);
 414                                 return error;
 415                         }
 416                 }
 417
 418                 if (addr != (void *)1) {
 419                         if ((error = ptrace_set_pc (p,
 420                             (u_long)(uintfptr_t)addr))) {
 421                                 PRELE(p);
 422                                 return error;
 423                         }
 424                 }
 425                 PRELE(p);
 426
 427                 if (req == PT_DETACH) {
 428                         /* reset process parent */
 429                         if (p->p_oppid != p->p_pptr->p_pid) {
 430                                 struct proc *pp;
 431
 432                                 pp = pfind(p->p_oppid);
 433                                 proc_reparent(p, pp ? pp : initproc);
 434                         }
 435
 436                         p->p_flag &= ~(P_TRACED | P_WAITED);
 437                         p->p_oppid = 0;
 438
 439                         /* should we send SIGCHLD? */
 440                 }
 441
 442         sendsig:
 443                 /*
 444                  * Deliver or queue signal.  If the process is stopped
 445                  * force it to SRUN again.
 446                  */
 447                 crit_enter();
 448                 if (p->p_flag & P_STOPPED) {
 449                         p->p_xstat = data;
 450                         p->p_flag |= P_BREAKTSLEEP;
 451                         setrunnable(p);
 452                 } else if (data) {
 453                         psignal(p, data);
 454                 }
 455                 crit_exit();
 456                 return 0;
 457
 458         case PT_WRITE_I:
 459         case PT_WRITE_D:
 460                 write = 1;
 461                 /* fallthrough */
 462         case PT_READ_I:
 463         case PT_READ_D:
 464                 /*
 465                  * NOTE! uio_offset represents the offset in the target
 466                  * process.  The iov is in the current process (the guy
 467                  * making the ptrace call) so uio_td must be the current
 468                  * process (though for a SYSSPACE transfer it doesn't
 469                  * really matter).
 470                  */
 471                 tmp = 0;
 472                 /* write = 0 set above */
 473                 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
 474                 iov.iov_len = sizeof(int);
 475                 uio.uio_iov = &iov;
 476                 uio.uio_iovcnt = 1;
 477                 uio.uio_offset = (off_t)(uintptr_t)addr;
 478                 uio.uio_resid = sizeof(int);
 479                 uio.uio_segflg = UIO_SYSSPACE;
 480                 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
 481                 uio.uio_td = curp->p_thread;
 482                 error = procfs_domem(curp, p, NULL, &uio);
 483                 if (uio.uio_resid != 0) {
 484                         /*
 485                          * XXX procfs_domem() doesn't currently return ENOSPC,
 486                          * so I think write() can bogusly return 0.
 487                          * XXX what happens for short writes?  We don't want
 488                          * to write partial data.
 489                          * XXX procfs_domem() returns EPERM for other invalid
 490                          * addresses.  Convert this to EINVAL.  Does this
 491                          * clobber returns of EPERM for other reasons?
 492                          */
 493                         if (error == 0 || error == ENOSPC || error == EPERM)
 494                                 error = EINVAL; /* EOF */
 495                 }
 496                 if (!write)
 497                         *res = tmp;
 498                 return (error);
 499
 500         case PT_IO:
 501                 /*
 502                  * NOTE! uio_offset represents the offset in the target
 503                  * process.  The iov is in the current process (the guy
 504                  * making the ptrace call) so uio_td must be the current
 505                  * process.
 506                  */
 507                 piod = addr;
 508                 iov.iov_base = piod->piod_addr;
 509                 iov.iov_len = piod->piod_len;
 510                 uio.uio_iov = &iov;
 511                 uio.uio_iovcnt = 1;
 512                 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
 513                 uio.uio_resid = piod->piod_len;
 514                 uio.uio_segflg = UIO_USERSPACE;
 515                 uio.uio_td = curp->p_thread;
 516                 switch (piod->piod_op) {
 517                 case PIOD_READ_D:
 518                 case PIOD_READ_I:
 519                         uio.uio_rw = UIO_READ;
 520                         break;
 521                 case PIOD_WRITE_D:
 522                 case PIOD_WRITE_I:
 523                         uio.uio_rw = UIO_WRITE;
 524                         break;
 525                 default:
 526                         return (EINVAL);
 527                 }
 528                 error = procfs_domem(curp, p, NULL, &uio);
 529                 piod->piod_len -= uio.uio_resid;
 530                 return (error);
 531
 532         case PT_KILL:
 533                 data = SIGKILL;
 534                 goto sendsig;   /* in PT_CONTINUE above */
 535
 536 #ifdef PT_SETREGS
 537         case PT_SETREGS:
 538                 write = 1;
 539                 /* fallthrough */
 540 #endif /* PT_SETREGS */
 541 #ifdef PT_GETREGS
 542         case PT_GETREGS:
 543                 /* write = 0 above */
 544 #endif /* PT_SETREGS */
 545 #if defined(PT_SETREGS) || defined(PT_GETREGS)
 546                 if (!procfs_validregs(p))       /* no P_SYSTEM procs please */
 547                         return EINVAL;
 548                 else {
 549                         iov.iov_base = addr;
 550                         iov.iov_len = sizeof(struct reg);
 551                         uio.uio_iov = &iov;
 552                         uio.uio_iovcnt = 1;
 553                         uio.uio_offset = 0;
 554                         uio.uio_resid = sizeof(struct reg);
 555                         uio.uio_segflg = UIO_SYSSPACE;
 556                         uio.uio_rw = write ? UIO_WRITE : UIO_READ;
 557                         uio.uio_td = curp->p_thread;
 558                         return (procfs_doregs(curp, p, NULL, &uio));
 559                 }
 560 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */
 561
 562 #ifdef PT_SETFPREGS
 563         case PT_SETFPREGS:
 564                 write = 1;
 565                 /* fallthrough */
 566 #endif /* PT_SETFPREGS */
 567 #ifdef PT_GETFPREGS
 568         case PT_GETFPREGS:
 569                 /* write = 0 above */
 570 #endif /* PT_SETFPREGS */
 571 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
 572                 if (!procfs_validfpregs(p))     /* no P_SYSTEM procs please */
 573                         return EINVAL;
 574                 else {
 575                         iov.iov_base = addr;
 576                         iov.iov_len = sizeof(struct fpreg);
 577                         uio.uio_iov = &iov;
 578                         uio.uio_iovcnt = 1;
 579                         uio.uio_offset = 0;
 580                         uio.uio_resid = sizeof(struct fpreg);
 581                         uio.uio_segflg = UIO_SYSSPACE;
 582                         uio.uio_rw = write ? UIO_WRITE : UIO_READ;
 583                         uio.uio_td = curp->p_thread;
 584                         return (procfs_dofpregs(curp, p, NULL, &uio));
 585                 }
 586 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */
 587
 588 #ifdef PT_SETDBREGS
 589         case PT_SETDBREGS:
 590                 write = 1;
 591                 /* fallthrough */
 592 #endif /* PT_SETDBREGS */
 593 #ifdef PT_GETDBREGS
 594         case PT_GETDBREGS:
 595                 /* write = 0 above */
 596 #endif /* PT_SETDBREGS */
 597 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS)
 598                 if (!procfs_validdbregs(p))     /* no P_SYSTEM procs please */
 599                         return EINVAL;
 600                 else {
 601                         iov.iov_base = addr;
 602                         iov.iov_len = sizeof(struct dbreg);
 603                         uio.uio_iov = &iov;
 604                         uio.uio_iovcnt = 1;
 605                         uio.uio_offset = 0;
 606                         uio.uio_resid = sizeof(struct dbreg);
 607                         uio.uio_segflg = UIO_SYSSPACE;
 608                         uio.uio_rw = write ? UIO_WRITE : UIO_READ;
 609                         uio.uio_td = curp->p_thread;
 610                         return (procfs_dodbregs(curp, p, NULL, &uio));
 611                 }
 612 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */
 613
 614         default:
 615                 break;
 616         }
 617
 618         return 0;
 619 }
 620
 621 int
 622 trace_req(p)
 623         struct proc *p;
 624 {
 625         return 1;
 626 }
 627
 628 /*
 629  * stopevent()
 630  *
 631  * Stop a process because of a procfs event.  Stay stopped until p->p_step
 632  * is cleared (cleared by PIOCCONT in procfs).
 633  *
 634  * MPSAFE
 635  */
 636 void
 637 stopevent(struct proc *p, unsigned int event, unsigned int val)
 638 {
 639         p->p_step = 1;
 640
 641         do {
 642                 crit_enter();
 643                 wakeup(&p->p_stype);    /* Wake up any PIOCWAIT'ing procs */
 644                 p->p_xstat = val;
 645                 p->p_stype = event;     /* Which event caused the stop? */
 646                 tsleep(&p->p_step, 0, "stopevent", 0);
 647                 crit_exit();
 648         } while (p->p_step);
 649 }
 650