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 1.14 2003/10/15 21:52:38 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, s; 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_stat != SSTOP || (p->p_flag & P_WAITED) == 0) 362 return EBUSY; 363 364 /* OK */ 365 break; 366 367 default: 368 return EINVAL; 369 } 370 371 #ifdef FIX_SSTEP 372 /* 373 * Single step fixup ala procfs 374 */ 375 FIX_SSTEP(p); 376 #endif 377 378 /* 379 * Actually do the requests 380 */ 381 382 *res = 0; 383 384 switch (req) { 385 case PT_TRACE_ME: 386 /* set my trace flag and "owner" so it can read/write me */ 387 p->p_flag |= P_TRACED; 388 p->p_oppid = p->p_pptr->p_pid; 389 return 0; 390 391 case PT_ATTACH: 392 /* security check done above */ 393 p->p_flag |= P_TRACED; 394 p->p_oppid = p->p_pptr->p_pid; 395 if (p->p_pptr != curp) 396 proc_reparent(p, curp); 397 data = SIGSTOP; 398 goto sendsig; /* in PT_CONTINUE below */ 399 400 case PT_STEP: 401 case PT_CONTINUE: 402 case PT_DETACH: 403 /* Zero means do not send any signal */ 404 if (data < 0 || data > _SIG_MAXSIG) 405 return EINVAL; 406 407 PHOLD(p); 408 409 if (req == PT_STEP) { 410 if ((error = ptrace_single_step (p))) { 411 PRELE(p); 412 return error; 413 } 414 } 415 416 if (addr != (void *)1) { 417 if ((error = ptrace_set_pc (p, 418 (u_long)(uintfptr_t)addr))) { 419 PRELE(p); 420 return error; 421 } 422 } 423 PRELE(p); 424 425 if (req == PT_DETACH) { 426 /* reset process parent */ 427 if (p->p_oppid != p->p_pptr->p_pid) { 428 struct proc *pp; 429 430 pp = pfind(p->p_oppid); 431 proc_reparent(p, pp ? pp : initproc); 432 } 433 434 p->p_flag &= ~(P_TRACED | P_WAITED); 435 p->p_oppid = 0; 436 437 /* should we send SIGCHLD? */ 438 } 439 440 sendsig: 441 /* deliver or queue signal */ 442 s = splhigh(); 443 if (p->p_stat == SSTOP) { 444 p->p_xstat = data; 445 setrunnable(p); 446 } else if (data) { 447 psignal(p, data); 448 } 449 splx(s); 450 return 0; 451 452 case PT_WRITE_I: 453 case PT_WRITE_D: 454 write = 1; 455 /* fallthrough */ 456 case PT_READ_I: 457 case PT_READ_D: 458 /* 459 * NOTE! uio_offset represents the offset in the target 460 * process. The iov is in the current process (the guy 461 * making the ptrace call) so uio_td must be the current 462 * process (though for a SYSSPACE transfer it doesn't 463 * really matter). 464 */ 465 tmp = 0; 466 /* write = 0 set above */ 467 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp; 468 iov.iov_len = sizeof(int); 469 uio.uio_iov = &iov; 470 uio.uio_iovcnt = 1; 471 uio.uio_offset = (off_t)(uintptr_t)addr; 472 uio.uio_resid = sizeof(int); 473 uio.uio_segflg = UIO_SYSSPACE; 474 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 475 uio.uio_td = curp->p_thread; 476 error = procfs_domem(curp, p, NULL, &uio); 477 if (uio.uio_resid != 0) { 478 /* 479 * XXX procfs_domem() doesn't currently return ENOSPC, 480 * so I think write() can bogusly return 0. 481 * XXX what happens for short writes? We don't want 482 * to write partial data. 483 * XXX procfs_domem() returns EPERM for other invalid 484 * addresses. Convert this to EINVAL. Does this 485 * clobber returns of EPERM for other reasons? 486 */ 487 if (error == 0 || error == ENOSPC || error == EPERM) 488 error = EINVAL; /* EOF */ 489 } 490 if (!write) 491 *res = tmp; 492 return (error); 493 494 case PT_IO: 495 /* 496 * NOTE! uio_offset represents the offset in the target 497 * process. The iov is in the current process (the guy 498 * making the ptrace call) so uio_td must be the current 499 * process. 500 */ 501 piod = addr; 502 iov.iov_base = piod->piod_addr; 503 iov.iov_len = piod->piod_len; 504 uio.uio_iov = &iov; 505 uio.uio_iovcnt = 1; 506 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs; 507 uio.uio_resid = piod->piod_len; 508 uio.uio_segflg = UIO_USERSPACE; 509 uio.uio_td = curp->p_thread; 510 switch (piod->piod_op) { 511 case PIOD_READ_D: 512 case PIOD_READ_I: 513 uio.uio_rw = UIO_READ; 514 break; 515 case PIOD_WRITE_D: 516 case PIOD_WRITE_I: 517 uio.uio_rw = UIO_WRITE; 518 break; 519 default: 520 return (EINVAL); 521 } 522 error = procfs_domem(curp, p, NULL, &uio); 523 piod->piod_len -= uio.uio_resid; 524 return (error); 525 526 case PT_KILL: 527 data = SIGKILL; 528 goto sendsig; /* in PT_CONTINUE above */ 529 530 #ifdef PT_SETREGS 531 case PT_SETREGS: 532 write = 1; 533 /* fallthrough */ 534 #endif /* PT_SETREGS */ 535 #ifdef PT_GETREGS 536 case PT_GETREGS: 537 /* write = 0 above */ 538 #endif /* PT_SETREGS */ 539 #if defined(PT_SETREGS) || defined(PT_GETREGS) 540 if (!procfs_validregs(p)) /* no P_SYSTEM procs please */ 541 return EINVAL; 542 else { 543 iov.iov_base = addr; 544 iov.iov_len = sizeof(struct reg); 545 uio.uio_iov = &iov; 546 uio.uio_iovcnt = 1; 547 uio.uio_offset = 0; 548 uio.uio_resid = sizeof(struct reg); 549 uio.uio_segflg = UIO_SYSSPACE; 550 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 551 uio.uio_td = curp->p_thread; 552 return (procfs_doregs(curp, p, NULL, &uio)); 553 } 554 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */ 555 556 #ifdef PT_SETFPREGS 557 case PT_SETFPREGS: 558 write = 1; 559 /* fallthrough */ 560 #endif /* PT_SETFPREGS */ 561 #ifdef PT_GETFPREGS 562 case PT_GETFPREGS: 563 /* write = 0 above */ 564 #endif /* PT_SETFPREGS */ 565 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 566 if (!procfs_validfpregs(p)) /* no P_SYSTEM procs please */ 567 return EINVAL; 568 else { 569 iov.iov_base = addr; 570 iov.iov_len = sizeof(struct fpreg); 571 uio.uio_iov = &iov; 572 uio.uio_iovcnt = 1; 573 uio.uio_offset = 0; 574 uio.uio_resid = sizeof(struct fpreg); 575 uio.uio_segflg = UIO_SYSSPACE; 576 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 577 uio.uio_td = curp->p_thread; 578 return (procfs_dofpregs(curp, p, NULL, &uio)); 579 } 580 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */ 581 582 #ifdef PT_SETDBREGS 583 case PT_SETDBREGS: 584 write = 1; 585 /* fallthrough */ 586 #endif /* PT_SETDBREGS */ 587 #ifdef PT_GETDBREGS 588 case PT_GETDBREGS: 589 /* write = 0 above */ 590 #endif /* PT_SETDBREGS */ 591 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS) 592 if (!procfs_validdbregs(p)) /* no P_SYSTEM procs please */ 593 return EINVAL; 594 else { 595 iov.iov_base = addr; 596 iov.iov_len = sizeof(struct dbreg); 597 uio.uio_iov = &iov; 598 uio.uio_iovcnt = 1; 599 uio.uio_offset = 0; 600 uio.uio_resid = sizeof(struct dbreg); 601 uio.uio_segflg = UIO_SYSSPACE; 602 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 603 uio.uio_td = curp->p_thread; 604 return (procfs_dodbregs(curp, p, NULL, &uio)); 605 } 606 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */ 607 608 default: 609 break; 610 } 611 612 return 0; 613 } 614 615 int 616 trace_req(p) 617 struct proc *p; 618 { 619 return 1; 620 } 621 622 /* 623 * stopevent() 624 * Stop a process because of a procfs event; 625 * stay stopped until p->p_step is cleared 626 * (cleared by PIOCCONT in procfs). 627 */ 628 629 void 630 stopevent(struct proc *p, unsigned int event, unsigned int val) 631 { 632 p->p_step = 1; 633 634 do { 635 crit_enter(); 636 wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */ 637 p->p_xstat = val; 638 p->p_stype = event; /* Which event caused the stop? */ 639 tsleep(&p->p_step, 0, "stopevent", 0); 640 crit_exit(); 641 } while (p->p_step); 642 } 643 644