Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/sys_process.c
Version:
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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 * $FreeBSD$ 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/sysproto.h> 37 #include <sys/proc.h> 38 #include <sys/vnode.h> 39 #include <sys/ptrace.h> 40 41 #include <machine/reg.h> 42 #include <vm/vm.h> 43 #include <sys/lock.h> 44 #include <vm/pmap.h> 45 #include <vm/vm_map.h> 46 #include <vm/vm_page.h> 47 48 #include <sys/user.h> 49 #include <miscfs/procfs/procfs.h> 50 51 /* use the equivalent procfs code */ 52 #if 0 53 static int 54 pread (struct proc *procp, unsigned int addr, unsigned int *retval) { 55 int rv; 56 vm_map_t map, tmap; 57 vm_object_t object; 58 vm_offset_t kva = 0; 59 int page_offset; /* offset into page */ 60 vm_offset_t pageno; /* page number */ 61 vm_map_entry_t out_entry; 62 vm_prot_t out_prot; 63 boolean_t wired; 64 vm_pindex_t pindex; 65 66 /* Map page into kernel space */ 67 68 map = &procp->p_vmspace->vm_map; 69 70 page_offset = addr - trunc_page(addr); 71 pageno = trunc_page(addr); 72 73 tmap = map; 74 rv = vm_map_lookup (&tmap, pageno, VM_PROT_READ, &out_entry, 75 &object, &pindex, &out_prot, &wired); 76 77 if (rv != KERN_SUCCESS) 78 return EINVAL; 79 80 vm_map_lookup_done (tmap, out_entry); 81 82 /* Find space in kernel_map for the page we're interested in */ 83 rv = vm_map_find (kernel_map, object, IDX_TO_OFF(pindex), 84 &kva, PAGE_SIZE, 0, VM_PROT_ALL, VM_PROT_ALL, 0); 85 86 if (!rv) { 87 vm_object_reference (object); 88 89 rv = vm_map_pageable (kernel_map, kva, kva + PAGE_SIZE, 0); 90 if (!rv) { 91 *retval = 0; 92 bcopy ((caddr_t)kva + page_offset, 93 retval, sizeof *retval); 94 } 95 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE); 96 } 97 98 return rv; 99 } 100 101 static int 102 pwrite (struct proc *procp, unsigned int addr, unsigned int datum) { 103 int rv; 104 vm_map_t map, tmap; 105 vm_object_t object; 106 vm_offset_t kva = 0; 107 int page_offset; /* offset into page */ 108 vm_offset_t pageno; /* page number */ 109 vm_map_entry_t out_entry; 110 vm_prot_t out_prot; 111 boolean_t wired; 112 vm_pindex_t pindex; 113 boolean_t fix_prot = 0; 114 115 /* Map page into kernel space */ 116 117 map = &procp->p_vmspace->vm_map; 118 119 page_offset = addr - trunc_page(addr); 120 pageno = trunc_page(addr); 121 122 /* 123 * Check the permissions for the area we're interested in. 124 */ 125 126 if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE, 127 VM_PROT_WRITE) == FALSE) { 128 /* 129 * If the page was not writable, we make it so. 130 * XXX It is possible a page may *not* be read/executable, 131 * if a process changes that! 132 */ 133 fix_prot = 1; 134 /* The page isn't writable, so let's try making it so... */ 135 if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE, 136 VM_PROT_ALL, 0)) != KERN_SUCCESS) 137 return EFAULT; /* I guess... */ 138 } 139 140 /* 141 * Now we need to get the page. out_entry, out_prot, wired, and 142 * single_use aren't used. One would think the vm code would be 143 * a *bit* nicer... We use tmap because vm_map_lookup() can 144 * change the map argument. 145 */ 146 147 tmap = map; 148 rv = vm_map_lookup (&tmap, pageno, VM_PROT_WRITE, &out_entry, 149 &object, &pindex, &out_prot, &wired); 150 if (rv != KERN_SUCCESS) { 151 return EINVAL; 152 } 153 154 /* 155 * Okay, we've got the page. Let's release tmap. 156 */ 157 158 vm_map_lookup_done (tmap, out_entry); 159 160 /* 161 * Fault the page in... 162 */ 163 164 rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE); 165 if (rv != KERN_SUCCESS) 166 return EFAULT; 167 168 /* Find space in kernel_map for the page we're interested in */ 169 rv = vm_map_find (kernel_map, object, IDX_TO_OFF(pindex), 170 &kva, PAGE_SIZE, 0, 171 VM_PROT_ALL, VM_PROT_ALL, 0); 172 if (!rv) { 173 vm_object_reference (object); 174 175 rv = vm_map_pageable (kernel_map, kva, kva + PAGE_SIZE, 0); 176 if (!rv) { 177 bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum); 178 } 179 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE); 180 } 181 182 if (fix_prot) 183 vm_map_protect (map, pageno, pageno + PAGE_SIZE, 184 VM_PROT_READ|VM_PROT_EXECUTE, 0); 185 return rv; 186 } 187 #endif 188 189 /* 190 * Process debugging system call. 191 */ 192 #ifndef _SYS_SYSPROTO_H_ 193 struct ptrace_args { 194 int req; 195 pid_t pid; 196 caddr_t addr; 197 int data; 198 }; 199 #endif 200 201 int 202 ptrace(struct proc *p, struct ptrace_args *uap) 203 { 204 /* 205 * XXX this obfuscation is to reduce stack usage, but the register 206 * structs may be too large to put on the stack anyway. 207 */ 208 union { 209 struct ptrace_io_desc piod; 210 struct dbreg dbreg; 211 struct fpreg fpreg; 212 struct reg reg; 213 } r; 214 void *addr; 215 int error = 0; 216 217 addr = &r; 218 switch (uap->req) { 219 case PT_GETREGS: 220 case PT_GETFPREGS: 221 #ifdef PT_GETDBREGS 222 case PT_GETDBREGS: 223 #endif 224 break; 225 case PT_SETREGS: 226 error = copyin(uap->addr, &r.reg, sizeof r.reg); 227 break; 228 case PT_SETFPREGS: 229 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg); 230 break; 231 #ifdef PT_SETDBREGS 232 case PT_SETDBREGS: 233 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg); 234 break; 235 #endif 236 case PT_IO: 237 error = copyin(uap->addr, &r.piod, sizeof r.piod); 238 break; 239 default: 240 addr = uap->addr; 241 } 242 if (error) 243 return (error); 244 245 error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data); 246 if (error) 247 return (error); 248 249 switch (uap->req) { 250 case PT_IO: 251 (void)copyout(&r.piod, uap->addr, sizeof r.piod); 252 break; 253 case PT_GETREGS: 254 error = copyout(&r.reg, uap->addr, sizeof r.reg); 255 break; 256 case PT_GETFPREGS: 257 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg); 258 break; 259 #ifdef PT_GETDBREGS 260 case PT_GETDBREGS: 261 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg); 262 break; 263 #endif 264 } 265 266 return (error); 267 } 268 269 int 270 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr, int data) 271 { 272 struct proc *p, *pp; 273 struct iovec iov; 274 struct uio uio; 275 struct ptrace_io_desc *piod; 276 int error = 0; 277 int write, tmp, s; 278 279 write = 0; 280 if (req == PT_TRACE_ME) 281 p = curp; 282 else { 283 if ((p = pfind(pid)) == NULL) 284 return ESRCH; 285 } 286 if (!PRISON_CHECK(curp, p)) 287 return (ESRCH); 288 289 /* Can't trace a process that's currently exec'ing. */ 290 if ((p->p_flag & P_INEXEC) != 0) 291 return EAGAIN; 292 293 /* 294 * Permissions check 295 */ 296 switch (req) { 297 case PT_TRACE_ME: 298 /* Always legal. */ 299 break; 300 301 case PT_ATTACH: 302 /* Self */ 303 if (p->p_pid == curp->p_pid) 304 return EINVAL; 305 306 /* Already traced */ 307 if (p->p_flag & P_TRACED) 308 return EBUSY; 309 310 if (curp->p_flag & P_TRACED) 311 for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) 312 if (pp == p) 313 return (EINVAL); 314 315 /* not owned by you, has done setuid (unless you're root) */ 316 if ((p->p_cred->p_ruid != curp->p_cred->p_ruid) || 317 (p->p_flag & P_SUGID)) { 318 if ((error = suser(curp)) != 0) 319 return error; 320 } 321 322 /* can't trace init when securelevel > 0 */ 323 if (securelevel > 0 && p->p_pid == 1) 324 return EPERM; 325 326 /* OK */ 327 break; 328 329 case PT_READ_I: 330 case PT_READ_D: 331 case PT_WRITE_I: 332 case PT_WRITE_D: 333 case PT_IO: 334 case PT_CONTINUE: 335 case PT_KILL: 336 case PT_STEP: 337 case PT_DETACH: 338 #ifdef PT_GETREGS 339 case PT_GETREGS: 340 #endif 341 #ifdef PT_SETREGS 342 case PT_SETREGS: 343 #endif 344 #ifdef PT_GETFPREGS 345 case PT_GETFPREGS: 346 #endif 347 #ifdef PT_SETFPREGS 348 case PT_SETFPREGS: 349 #endif 350 #ifdef PT_GETDBREGS 351 case PT_GETDBREGS: 352 #endif 353 #ifdef PT_SETDBREGS 354 case PT_SETDBREGS: 355 #endif 356 /* not being traced... */ 357 if ((p->p_flag & P_TRACED) == 0) 358 return EPERM; 359 360 /* not being traced by YOU */ 361 if (p->p_pptr != curp) 362 return EBUSY; 363 364 /* not currently stopped */ 365 if (p->p_stat != SSTOP || (p->p_flag & P_WAITED) == 0) 366 return EBUSY; 367 368 /* OK */ 369 break; 370 371 default: 372 return EINVAL; 373 } 374 375 #ifdef FIX_SSTEP 376 /* 377 * Single step fixup ala procfs 378 */ 379 FIX_SSTEP(p); 380 #endif 381 382 /* 383 * Actually do the requests 384 */ 385 386 curp->p_retval[0] = 0; 387 388 switch (req) { 389 case PT_TRACE_ME: 390 /* set my trace flag and "owner" so it can read/write me */ 391 p->p_flag |= P_TRACED; 392 p->p_oppid = p->p_pptr->p_pid; 393 return 0; 394 395 case PT_ATTACH: 396 /* security check done above */ 397 p->p_flag |= P_TRACED; 398 p->p_oppid = p->p_pptr->p_pid; 399 if (p->p_pptr != curp) 400 proc_reparent(p, curp); 401 data = SIGSTOP; 402 goto sendsig; /* in PT_CONTINUE below */ 403 404 case PT_STEP: 405 case PT_CONTINUE: 406 case PT_DETACH: 407 /* Zero means do not send any signal */ 408 if (data < 0 || data > _SIG_MAXSIG) 409 return EINVAL; 410 411 PHOLD(p); 412 413 if (req == PT_STEP) { 414 if ((error = ptrace_single_step (p))) { 415 PRELE(p); 416 return error; 417 } 418 } 419 420 if (addr != (void *)1) { 421 if ((error = ptrace_set_pc (p, 422 (u_long)(uintfptr_t)addr))) { 423 PRELE(p); 424 return error; 425 } 426 } 427 PRELE(p); 428 429 if (req == PT_DETACH) { 430 /* reset process parent */ 431 if (p->p_oppid != p->p_pptr->p_pid) { 432 struct proc *pp; 433 434 pp = pfind(p->p_oppid); 435 proc_reparent(p, pp ? pp : initproc); 436 if (pp == NULL) 437 p->p_sigparent = SIGCHLD; 438 } 439 440 p->p_flag &= ~(P_TRACED | P_WAITED); 441 p->p_oppid = 0; 442 443 /* should we send SIGCHLD? */ 444 } 445 446 sendsig: 447 /* deliver or queue signal */ 448 s = splhigh(); 449 if (p->p_stat == SSTOP) { 450 p->p_xstat = data; 451 setrunnable(p); 452 } else if (data) { 453 psignal(p, data); 454 } 455 splx(s); 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 tmp = 0; 465 /* write = 0 set above */ 466 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp; 467 iov.iov_len = sizeof(int); 468 uio.uio_iov = &iov; 469 uio.uio_iovcnt = 1; 470 uio.uio_offset = (off_t)(uintptr_t)addr; 471 uio.uio_resid = sizeof(int); 472 uio.uio_segflg = UIO_SYSSPACE; 473 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 474 uio.uio_procp = p; 475 error = procfs_domem(curp, p, NULL, &uio); 476 if (uio.uio_resid != 0) { 477 /* 478 * XXX procfs_domem() doesn't currently return ENOSPC, 479 * so I think write() can bogusly return 0. 480 * XXX what happens for short writes? We don't want 481 * to write partial data. 482 * XXX procfs_domem() returns EPERM for other invalid 483 * addresses. Convert this to EINVAL. Does this 484 * clobber returns of EPERM for other reasons? 485 */ 486 if (error == 0 || error == ENOSPC || error == EPERM) 487 error = EINVAL; /* EOF */ 488 } 489 if (!write) 490 curp->p_retval[0] = tmp; 491 return (error); 492 493 case PT_IO: 494 piod = addr; 495 iov.iov_base = piod->piod_addr; 496 iov.iov_len = piod->piod_len; 497 uio.uio_iov = &iov; 498 uio.uio_iovcnt = 1; 499 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs; 500 uio.uio_resid = piod->piod_len; 501 uio.uio_segflg = UIO_USERSPACE; 502 uio.uio_procp = p; 503 switch (piod->piod_op) { 504 case PIOD_READ_D: 505 case PIOD_READ_I: 506 uio.uio_rw = UIO_READ; 507 break; 508 case PIOD_WRITE_D: 509 case PIOD_WRITE_I: 510 uio.uio_rw = UIO_WRITE; 511 break; 512 default: 513 return (EINVAL); 514 } 515 error = procfs_domem(curp, p, NULL, &uio); 516 piod->piod_len -= uio.uio_resid; 517 return (error); 518 519 case PT_KILL: 520 data = SIGKILL; 521 goto sendsig; /* in PT_CONTINUE above */ 522 523 #ifdef PT_SETREGS 524 case PT_SETREGS: 525 write = 1; 526 /* fallthrough */ 527 #endif /* PT_SETREGS */ 528 #ifdef PT_GETREGS 529 case PT_GETREGS: 530 /* write = 0 above */ 531 #endif /* PT_SETREGS */ 532 #if defined(PT_SETREGS) || defined(PT_GETREGS) 533 if (!procfs_validregs(p)) /* no P_SYSTEM procs please */ 534 return EINVAL; 535 else { 536 iov.iov_base = addr; 537 iov.iov_len = sizeof(struct reg); 538 uio.uio_iov = &iov; 539 uio.uio_iovcnt = 1; 540 uio.uio_offset = 0; 541 uio.uio_resid = sizeof(struct reg); 542 uio.uio_segflg = UIO_SYSSPACE; 543 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 544 uio.uio_procp = curp; 545 return (procfs_doregs(curp, p, NULL, &uio)); 546 } 547 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */ 548 549 #ifdef PT_SETFPREGS 550 case PT_SETFPREGS: 551 write = 1; 552 /* fallthrough */ 553 #endif /* PT_SETFPREGS */ 554 #ifdef PT_GETFPREGS 555 case PT_GETFPREGS: 556 /* write = 0 above */ 557 #endif /* PT_SETFPREGS */ 558 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 559 if (!procfs_validfpregs(p)) /* no P_SYSTEM procs please */ 560 return EINVAL; 561 else { 562 iov.iov_base = addr; 563 iov.iov_len = sizeof(struct fpreg); 564 uio.uio_iov = &iov; 565 uio.uio_iovcnt = 1; 566 uio.uio_offset = 0; 567 uio.uio_resid = sizeof(struct fpreg); 568 uio.uio_segflg = UIO_SYSSPACE; 569 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 570 uio.uio_procp = curp; 571 return (procfs_dofpregs(curp, p, NULL, &uio)); 572 } 573 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */ 574 575 #ifdef PT_SETDBREGS 576 case PT_SETDBREGS: 577 write = 1; 578 /* fallthrough */ 579 #endif /* PT_SETDBREGS */ 580 #ifdef PT_GETDBREGS 581 case PT_GETDBREGS: 582 /* write = 0 above */ 583 #endif /* PT_SETDBREGS */ 584 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS) 585 if (!procfs_validdbregs(p)) /* no P_SYSTEM procs please */ 586 return EINVAL; 587 else { 588 iov.iov_base = addr; 589 iov.iov_len = sizeof(struct dbreg); 590 uio.uio_iov = &iov; 591 uio.uio_iovcnt = 1; 592 uio.uio_offset = 0; 593 uio.uio_resid = sizeof(struct dbreg); 594 uio.uio_segflg = UIO_SYSSPACE; 595 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 596 uio.uio_procp = curp; 597 return (procfs_dodbregs(curp, p, NULL, &uio)); 598 } 599 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */ 600 601 default: 602 break; 603 } 604 605 return 0; 606 } 607 608 int 609 trace_req(p) 610 struct proc *p; 611 { 612 return 1; 613 } 614 615 /* 616 * stopevent() 617 * Stop a process because of a procfs event; 618 * stay stopped until p->p_step is cleared 619 * (cleared by PIOCCONT in procfs). 620 */ 621 622 void 623 stopevent(struct proc *p, unsigned int event, unsigned int val) { 624 p->p_step = 1; 625 626 do { 627 p->p_xstat = val; 628 p->p_stype = event; /* Which event caused the stop? */ 629 wakeup(&p->p_stype); /* Wake up any PIOCWAIT'ing procs */ 630 tsleep(&p->p_step, PWAIT, "stopevent", 0); 631 } while (p->p_step); 632 }
Cache object: d206a14bbf3b7062d3ecc24f916d3a95
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