1 /* 2 * Copyright (c) 1993, David Greenman 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/lock.h> 32 #include <sys/mutex.h> 33 #include <sys/sysproto.h> 34 #include <sys/signalvar.h> 35 #include <sys/kernel.h> 36 #include <sys/mount.h> 37 #include <sys/filedesc.h> 38 #include <sys/fcntl.h> 39 #include <sys/acct.h> 40 #include <sys/exec.h> 41 #include <sys/imgact.h> 42 #include <sys/imgact_elf.h> 43 #include <sys/wait.h> 44 #include <sys/malloc.h> 45 #include <sys/proc.h> 46 #include <sys/pioctl.h> 47 #include <sys/namei.h> 48 #include <sys/sysent.h> 49 #include <sys/shm.h> 50 #include <sys/sysctl.h> 51 #include <sys/user.h> 52 #include <sys/vnode.h> 53 54 #include <vm/vm.h> 55 #include <vm/vm_param.h> 56 #include <vm/pmap.h> 57 #include <vm/vm_page.h> 58 #include <vm/vm_map.h> 59 #include <vm/vm_kern.h> 60 #include <vm/vm_extern.h> 61 #include <vm/vm_object.h> 62 #include <vm/vm_pager.h> 63 64 #include <machine/reg.h> 65 66 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 67 68 static MALLOC_DEFINE(M_ATEXEC, "atexec", "atexec callback"); 69 70 /* 71 * callout list for things to do at exec time 72 */ 73 struct execlist { 74 execlist_fn function; 75 TAILQ_ENTRY(execlist) next; 76 }; 77 78 TAILQ_HEAD(exec_list_head, execlist); 79 static struct exec_list_head exec_list = TAILQ_HEAD_INITIALIZER(exec_list); 80 81 static register_t *exec_copyout_strings __P((struct image_params *)); 82 83 /* XXX This should be vm_size_t. */ 84 static u_long ps_strings = PS_STRINGS; 85 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, ""); 86 87 /* XXX This should be vm_size_t. */ 88 static u_long usrstack = USRSTACK; 89 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, ""); 90 91 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 92 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 93 &ps_arg_cache_limit, 0, ""); 94 95 int ps_argsopen = 1; 96 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); 97 98 /* 99 * Each of the items is a pointer to a `const struct execsw', hence the 100 * double pointer here. 101 */ 102 static const struct execsw **execsw; 103 104 #ifndef _SYS_SYSPROTO_H_ 105 struct execve_args { 106 char *fname; 107 char **argv; 108 char **envv; 109 }; 110 #endif 111 112 /* 113 * execve() system call. 114 * 115 * MPSAFE 116 */ 117 int 118 execve(td, uap) 119 struct thread *td; 120 register struct execve_args *uap; 121 { 122 struct proc *p = td->td_proc; 123 struct nameidata nd, *ndp; 124 struct ucred *newcred, *oldcred; 125 register_t *stack_base; 126 int error, len, i; 127 struct image_params image_params, *imgp; 128 struct vattr attr; 129 int (*img_first) __P((struct image_params *)); 130 struct pargs *pa; 131 struct execlist *ep; 132 133 imgp = &image_params; 134 135 /* 136 * Lock the process and set the P_INEXEC flag to indicate that 137 * it should be left alone until we're done here. This is 138 * necessary to avoid race conditions - e.g. in ptrace() - 139 * that might allow a local user to illicitly obtain elevated 140 * privileges. 141 */ 142 mtx_lock(&Giant); 143 PROC_LOCK(p); 144 KASSERT((p->p_flag & P_INEXEC) == 0, 145 ("%s(): process already has P_INEXEC flag", __func__)); 146 p->p_flag |= P_INEXEC; 147 PROC_UNLOCK(p); 148 149 /* XXXKSE */ 150 /* !!!!!!!! we need abort all the other threads of this process before we */ 151 /* proceed beyond his point! */ 152 153 /* 154 * Initialize part of the common data 155 */ 156 imgp->proc = p; 157 imgp->uap = uap; 158 imgp->attr = &attr; 159 imgp->argc = imgp->envc = 0; 160 imgp->argv0 = NULL; 161 imgp->entry_addr = 0; 162 imgp->vmspace_destroyed = 0; 163 imgp->interpreted = 0; 164 imgp->interpreter_name[0] = '\0'; 165 imgp->auxargs = NULL; 166 imgp->vp = NULL; 167 imgp->firstpage = NULL; 168 imgp->ps_strings = 0; 169 imgp->auxarg_size = 0; 170 171 /* 172 * Allocate temporary demand zeroed space for argument and 173 * environment strings 174 */ 175 imgp->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX + PAGE_SIZE); 176 if (imgp->stringbase == NULL) { 177 error = ENOMEM; 178 goto exec_fail; 179 } 180 imgp->stringp = imgp->stringbase; 181 imgp->stringspace = ARG_MAX; 182 imgp->image_header = imgp->stringbase + ARG_MAX; 183 184 /* 185 * Translate the file name. namei() returns a vnode pointer 186 * in ni_vp amoung other things. 187 */ 188 ndp = &nd; 189 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 190 UIO_USERSPACE, uap->fname, td); 191 192 interpret: 193 194 error = namei(ndp); 195 if (error) { 196 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 197 ARG_MAX + PAGE_SIZE); 198 goto exec_fail; 199 } 200 201 imgp->vp = ndp->ni_vp; 202 imgp->fname = uap->fname; 203 204 /* 205 * Check file permissions (also 'opens' file) 206 */ 207 error = exec_check_permissions(imgp); 208 if (error) { 209 VOP_UNLOCK(imgp->vp, 0, td); 210 goto exec_fail_dealloc; 211 } 212 213 error = exec_map_first_page(imgp); 214 VOP_UNLOCK(imgp->vp, 0, td); 215 if (error) 216 goto exec_fail_dealloc; 217 218 /* 219 * If the current process has a special image activator it 220 * wants to try first, call it. For example, emulating shell 221 * scripts differently. 222 */ 223 error = -1; 224 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 225 error = img_first(imgp); 226 227 /* 228 * Loop through the list of image activators, calling each one. 229 * An activator returns -1 if there is no match, 0 on success, 230 * and an error otherwise. 231 */ 232 for (i = 0; error == -1 && execsw[i]; ++i) { 233 if (execsw[i]->ex_imgact == NULL || 234 execsw[i]->ex_imgact == img_first) { 235 continue; 236 } 237 error = (*execsw[i]->ex_imgact)(imgp); 238 } 239 240 if (error) { 241 if (error == -1) 242 error = ENOEXEC; 243 goto exec_fail_dealloc; 244 } 245 246 /* 247 * Special interpreter operation, cleanup and loop up to try to 248 * activate the interpreter. 249 */ 250 if (imgp->interpreted) { 251 exec_unmap_first_page(imgp); 252 /* free name buffer and old vnode */ 253 NDFREE(ndp, NDF_ONLY_PNBUF); 254 vrele(ndp->ni_vp); 255 /* set new name to that of the interpreter */ 256 NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME, 257 UIO_SYSSPACE, imgp->interpreter_name, td); 258 goto interpret; 259 } 260 261 TAILQ_FOREACH(ep, &exec_list, next) 262 (*ep->function)(p); 263 264 /* 265 * Copy out strings (args and env) and initialize stack base 266 */ 267 stack_base = exec_copyout_strings(imgp); 268 p->p_vmspace->vm_minsaddr = (char *)stack_base; 269 270 /* 271 * If custom stack fixup routine present for this process 272 * let it do the stack setup. 273 * Else stuff argument count as first item on stack 274 */ 275 if (p->p_sysent->sv_fixup) 276 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 277 else 278 suword(--stack_base, imgp->argc); 279 280 /* 281 * For security and other reasons, the file descriptor table cannot 282 * be shared after an exec. 283 */ 284 if (p->p_fd->fd_refcnt > 1) { 285 struct filedesc *tmp; 286 287 tmp = fdcopy(td); 288 fdfree(td); 289 p->p_fd = tmp; 290 } 291 292 /* 293 * For security and other reasons, signal handlers cannot 294 * be shared after an exec. The new process gets a copy of the old 295 * handlers. In execsigs(), the new process will have its signals 296 * reset. 297 */ 298 if (p->p_procsig->ps_refcnt > 1) { 299 struct procsig *newprocsig; 300 301 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), 302 M_SUBPROC, M_WAITOK); 303 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig)); 304 p->p_procsig->ps_refcnt--; 305 p->p_procsig = newprocsig; 306 p->p_procsig->ps_refcnt = 1; 307 if (p->p_sigacts == &p->p_uarea->u_sigacts) 308 panic("shared procsig but private sigacts?"); 309 310 p->p_uarea->u_sigacts = *p->p_sigacts; 311 p->p_sigacts = &p->p_uarea->u_sigacts; 312 } 313 /* Stop profiling */ 314 stopprofclock(p); 315 316 /* close files on exec */ 317 fdcloseexec(td); 318 319 /* reset caught signals */ 320 execsigs(p); 321 322 /* name this process - nameiexec(p, ndp) */ 323 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 324 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 325 p->p_comm[len] = 0; 326 327 /* 328 * mark as execed, wakeup the process that vforked (if any) and tell 329 * it that it now has its own resources back 330 */ 331 PROC_LOCK(p); 332 p->p_flag |= P_EXEC; 333 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 334 p->p_flag &= ~P_PPWAIT; 335 wakeup((caddr_t)p->p_pptr); 336 } 337 338 /* 339 * Implement image setuid/setgid. 340 * 341 * Don't honor setuid/setgid if the filesystem prohibits it or if 342 * the process is being traced. 343 */ 344 oldcred = p->p_ucred; 345 newcred = NULL; 346 if ((((attr.va_mode & VSUID) && oldcred->cr_uid != attr.va_uid) || 347 ((attr.va_mode & VSGID) && oldcred->cr_gid != attr.va_gid)) && 348 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 349 (p->p_flag & P_TRACED) == 0) { 350 PROC_UNLOCK(p); 351 /* 352 * Turn off syscall tracing for set-id programs, except for 353 * root. Record any set-id flags first to make sure that 354 * we do not regain any tracing during a possible block. 355 */ 356 setsugid(p); 357 if (p->p_tracep && suser_xxx(oldcred, NULL, PRISON_ROOT)) { 358 struct vnode *vtmp; 359 360 if ((vtmp = p->p_tracep) != NULL) { 361 p->p_tracep = NULL; 362 p->p_traceflag = 0; 363 vrele(vtmp); 364 } 365 } 366 /* 367 * Set the new credentials. 368 */ 369 newcred = crdup(oldcred); 370 if (attr.va_mode & VSUID) 371 change_euid(newcred, attr.va_uid); 372 if (attr.va_mode & VSGID) 373 change_egid(newcred, attr.va_gid); 374 setugidsafety(td); 375 } else { 376 if (oldcred->cr_uid == oldcred->cr_ruid && 377 oldcred->cr_gid == oldcred->cr_rgid) 378 p->p_flag &= ~P_SUGID; 379 PROC_UNLOCK(p); 380 } 381 382 /* 383 * Implement correct POSIX saved-id behavior. 384 * 385 * XXX: It's not clear that the existing behavior is 386 * POSIX-compliant. A number of sources indicate that the saved 387 * uid/gid should only be updated if the new ruid is not equal to 388 * the old ruid, or the new euid is not equal to the old euid and 389 * the new euid is not equal to the old ruid. The FreeBSD code 390 * always updates the saved uid/gid. Also, this code uses the new 391 * (replaced) euid and egid as the source, which may or may not be 392 * the right ones to use. 393 */ 394 if (newcred == NULL) { 395 if (oldcred->cr_svuid != oldcred->cr_uid || 396 oldcred->cr_svgid != oldcred->cr_gid) { 397 newcred = crdup(oldcred); 398 change_svuid(newcred, newcred->cr_uid); 399 change_svgid(newcred, newcred->cr_gid); 400 } 401 } else { 402 change_svuid(newcred, newcred->cr_uid); 403 change_svgid(newcred, newcred->cr_gid); 404 } 405 406 if (newcred != NULL) { 407 PROC_LOCK(p); 408 p->p_ucred = newcred; 409 PROC_UNLOCK(p); 410 crfree(oldcred); 411 } 412 413 /* 414 * Store the vp for use in procfs 415 */ 416 if (p->p_textvp) /* release old reference */ 417 vrele(p->p_textvp); 418 VREF(ndp->ni_vp); 419 p->p_textvp = ndp->ni_vp; 420 421 /* 422 * Notify others that we exec'd, and clear the P_INEXEC flag 423 * as we're now a bona fide freshly-execed process. 424 */ 425 PROC_LOCK(p); 426 KNOTE(&p->p_klist, NOTE_EXEC); 427 p->p_flag &= ~P_INEXEC; 428 429 /* 430 * If tracing the process, trap to debugger so breakpoints 431 * can be set before the program executes. 432 */ 433 _STOPEVENT(p, S_EXEC, 0); 434 435 if (p->p_flag & P_TRACED) 436 psignal(p, SIGTRAP); 437 438 /* clear "fork but no exec" flag, as we _are_ execing */ 439 p->p_acflag &= ~AFORK; 440 441 /* Free any previous argument cache */ 442 pa = p->p_args; 443 p->p_args = NULL; 444 PROC_UNLOCK(p); 445 if (pa != NULL && --pa->ar_ref == 0) 446 FREE(pa, M_PARGS); 447 448 /* Set values passed into the program in registers. */ 449 setregs(td, imgp->entry_addr, (u_long)(uintptr_t)stack_base, 450 imgp->ps_strings); 451 452 /* Cache arguments if they fit inside our allowance */ 453 i = imgp->endargs - imgp->stringbase; 454 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 455 MALLOC(pa, struct pargs *, sizeof(struct pargs) + i, 456 M_PARGS, M_WAITOK); 457 pa->ar_ref = 1; 458 pa->ar_length = i; 459 bcopy(imgp->stringbase, pa->ar_args, i); 460 PROC_LOCK(p); 461 p->p_args = pa; 462 PROC_UNLOCK(p); 463 } 464 465 exec_fail_dealloc: 466 467 /* 468 * free various allocated resources 469 */ 470 if (imgp->firstpage) 471 exec_unmap_first_page(imgp); 472 473 if (imgp->stringbase != NULL) 474 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->stringbase, 475 ARG_MAX + PAGE_SIZE); 476 477 if (imgp->vp) { 478 NDFREE(ndp, NDF_ONLY_PNBUF); 479 vrele(imgp->vp); 480 } 481 482 if (error == 0) 483 goto done2; 484 485 exec_fail: 486 /* we're done here, clear P_INEXEC */ 487 PROC_LOCK(p); 488 p->p_flag &= ~P_INEXEC; 489 PROC_UNLOCK(p); 490 491 if (imgp->vmspace_destroyed) { 492 /* sorry, no more process anymore. exit gracefully */ 493 exit1(td, W_EXITCODE(0, SIGABRT)); 494 /* NOT REACHED */ 495 error = 0; 496 } 497 done2: 498 mtx_unlock(&Giant); 499 return (error); 500 } 501 502 int 503 exec_map_first_page(imgp) 504 struct image_params *imgp; 505 { 506 int rv, i; 507 int initial_pagein; 508 vm_page_t ma[VM_INITIAL_PAGEIN]; 509 vm_object_t object; 510 511 GIANT_REQUIRED; 512 513 if (imgp->firstpage) { 514 exec_unmap_first_page(imgp); 515 } 516 517 VOP_GETVOBJECT(imgp->vp, &object); 518 519 ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 520 521 if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 522 initial_pagein = VM_INITIAL_PAGEIN; 523 if (initial_pagein > object->size) 524 initial_pagein = object->size; 525 for (i = 1; i < initial_pagein; i++) { 526 if ((ma[i] = vm_page_lookup(object, i)) != NULL) { 527 if ((ma[i]->flags & PG_BUSY) || ma[i]->busy) 528 break; 529 if (ma[i]->valid) 530 break; 531 vm_page_busy(ma[i]); 532 } else { 533 ma[i] = vm_page_alloc(object, i, VM_ALLOC_NORMAL); 534 if (ma[i] == NULL) 535 break; 536 } 537 } 538 initial_pagein = i; 539 540 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 541 ma[0] = vm_page_lookup(object, 0); 542 543 if ((rv != VM_PAGER_OK) || (ma[0] == NULL) || (ma[0]->valid == 0)) { 544 if (ma[0]) { 545 vm_page_protect(ma[0], VM_PROT_NONE); 546 vm_page_free(ma[0]); 547 } 548 return EIO; 549 } 550 } 551 552 vm_page_wire(ma[0]); 553 vm_page_wakeup(ma[0]); 554 555 pmap_kenter((vm_offset_t) imgp->image_header, VM_PAGE_TO_PHYS(ma[0])); 556 imgp->firstpage = ma[0]; 557 558 return 0; 559 } 560 561 void 562 exec_unmap_first_page(imgp) 563 struct image_params *imgp; 564 { 565 GIANT_REQUIRED; 566 567 if (imgp->firstpage) { 568 pmap_kremove((vm_offset_t) imgp->image_header); 569 vm_page_unwire(imgp->firstpage, 1); 570 imgp->firstpage = NULL; 571 } 572 } 573 574 /* 575 * Destroy old address space, and allocate a new stack 576 * The new stack is only SGROWSIZ large because it is grown 577 * automatically in trap.c. 578 */ 579 int 580 exec_new_vmspace(imgp) 581 struct image_params *imgp; 582 { 583 int error; 584 struct vmspace *vmspace = imgp->proc->p_vmspace; 585 vm_offset_t stack_addr = USRSTACK - maxssiz; 586 vm_map_t map = &vmspace->vm_map; 587 588 GIANT_REQUIRED; 589 590 imgp->vmspace_destroyed = 1; 591 592 /* 593 * Blow away entire process VM, if address space not shared, 594 * otherwise, create a new VM space so that other threads are 595 * not disrupted 596 */ 597 if (vmspace->vm_refcnt == 1) { 598 if (vmspace->vm_shm) 599 shmexit(imgp->proc); 600 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS); 601 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS); 602 } else { 603 vmspace_exec(imgp->proc); 604 vmspace = imgp->proc->p_vmspace; 605 map = &vmspace->vm_map; 606 } 607 608 /* Allocate a new stack */ 609 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz, 610 VM_PROT_ALL, VM_PROT_ALL, 0); 611 if (error) 612 return (error); 613 614 #ifdef __ia64__ 615 { 616 /* 617 * Allocate backing store. We really need something 618 * similar to vm_map_stack which can allow the backing 619 * store to grow upwards. This will do for now. 620 */ 621 vm_offset_t bsaddr; 622 bsaddr = USRSTACK - 2*maxssiz; 623 error = vm_map_find(&vmspace->vm_map, 0, 0, &bsaddr, 624 4*PAGE_SIZE, 0, 625 VM_PROT_ALL, VM_PROT_ALL, 0); 626 imgp->proc->p_thread.td_md.md_bspstore = bsaddr; 627 } 628 #endif 629 630 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 631 * VM_STACK case, but they are still used to monitor the size of the 632 * process stack so we can check the stack rlimit. 633 */ 634 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 635 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz; 636 637 return(0); 638 } 639 640 /* 641 * Copy out argument and environment strings from the old process 642 * address space into the temporary string buffer. 643 */ 644 int 645 exec_extract_strings(imgp) 646 struct image_params *imgp; 647 { 648 char **argv, **envv; 649 char *argp, *envp; 650 int error; 651 size_t length; 652 653 /* 654 * extract arguments first 655 */ 656 657 argv = imgp->uap->argv; 658 659 if (argv) { 660 argp = (caddr_t) (intptr_t) fuword(argv); 661 if (argp == (caddr_t) -1) 662 return (EFAULT); 663 if (argp) 664 argv++; 665 if (imgp->argv0) 666 argp = imgp->argv0; 667 if (argp) { 668 do { 669 if (argp == (caddr_t) -1) 670 return (EFAULT); 671 if ((error = copyinstr(argp, imgp->stringp, 672 imgp->stringspace, &length))) { 673 if (error == ENAMETOOLONG) 674 return(E2BIG); 675 return (error); 676 } 677 imgp->stringspace -= length; 678 imgp->stringp += length; 679 imgp->argc++; 680 } while ((argp = (caddr_t) (intptr_t) fuword(argv++))); 681 } 682 } 683 684 imgp->endargs = imgp->stringp; 685 686 /* 687 * extract environment strings 688 */ 689 690 envv = imgp->uap->envv; 691 692 if (envv) { 693 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) { 694 if (envp == (caddr_t) -1) 695 return (EFAULT); 696 if ((error = copyinstr(envp, imgp->stringp, 697 imgp->stringspace, &length))) { 698 if (error == ENAMETOOLONG) 699 return(E2BIG); 700 return (error); 701 } 702 imgp->stringspace -= length; 703 imgp->stringp += length; 704 imgp->envc++; 705 } 706 } 707 708 return (0); 709 } 710 711 /* 712 * Copy strings out to the new process address space, constructing 713 * new arg and env vector tables. Return a pointer to the base 714 * so that it can be used as the initial stack pointer. 715 */ 716 register_t * 717 exec_copyout_strings(imgp) 718 struct image_params *imgp; 719 { 720 int argc, envc; 721 char **vectp; 722 char *stringp, *destp; 723 register_t *stack_base; 724 struct ps_strings *arginfo; 725 int szsigcode; 726 727 /* 728 * Calculate string base and vector table pointers. 729 * Also deal with signal trampoline code for this exec type. 730 */ 731 arginfo = (struct ps_strings *)PS_STRINGS; 732 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); 733 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 734 roundup((ARG_MAX - imgp->stringspace), sizeof(char *)); 735 736 /* 737 * install sigcode 738 */ 739 if (szsigcode) 740 copyout(imgp->proc->p_sysent->sv_sigcode, 741 ((caddr_t)arginfo - szsigcode), szsigcode); 742 743 /* 744 * If we have a valid auxargs ptr, prepare some room 745 * on the stack. 746 */ 747 if (imgp->auxargs) { 748 /* 749 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for 750 * lower compatibility. 751 */ 752 imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size 753 : (AT_COUNT * 2); 754 /* 755 * The '+ 2' is for the null pointers at the end of each of 756 * the arg and env vector sets,and imgp->auxarg_size is room 757 * for argument of Runtime loader. 758 */ 759 vectp = (char **) (destp - (imgp->argc + imgp->envc + 2 + 760 imgp->auxarg_size) * sizeof(char *)); 761 762 } else 763 /* 764 * The '+ 2' is for the null pointers at the end of each of 765 * the arg and env vector sets 766 */ 767 vectp = (char **) 768 (destp - (imgp->argc + imgp->envc + 2) * sizeof(char *)); 769 770 /* 771 * vectp also becomes our initial stack base 772 */ 773 stack_base = (register_t *)vectp; 774 775 stringp = imgp->stringbase; 776 argc = imgp->argc; 777 envc = imgp->envc; 778 779 /* 780 * Copy out strings - arguments and environment. 781 */ 782 copyout(stringp, destp, ARG_MAX - imgp->stringspace); 783 784 /* 785 * Fill in "ps_strings" struct for ps, w, etc. 786 */ 787 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 788 suword(&arginfo->ps_nargvstr, argc); 789 790 /* 791 * Fill in argument portion of vector table. 792 */ 793 for (; argc > 0; --argc) { 794 suword(vectp++, (long)(intptr_t)destp); 795 while (*stringp++ != 0) 796 destp++; 797 destp++; 798 } 799 800 /* a null vector table pointer separates the argp's from the envp's */ 801 suword(vectp++, 0); 802 803 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 804 suword(&arginfo->ps_nenvstr, envc); 805 806 /* 807 * Fill in environment portion of vector table. 808 */ 809 for (; envc > 0; --envc) { 810 suword(vectp++, (long)(intptr_t)destp); 811 while (*stringp++ != 0) 812 destp++; 813 destp++; 814 } 815 816 /* end of vector table is a null pointer */ 817 suword(vectp, 0); 818 819 return (stack_base); 820 } 821 822 /* 823 * Check permissions of file to execute. 824 * Called with imgp->vp locked. 825 * Return 0 for success or error code on failure. 826 */ 827 int 828 exec_check_permissions(imgp) 829 struct image_params *imgp; 830 { 831 struct proc *p = imgp->proc; 832 struct vnode *vp = imgp->vp; 833 struct vattr *attr = imgp->attr; 834 int error; 835 836 /* Get file attributes */ 837 error = VOP_GETATTR(vp, attr, p->p_ucred, curthread); /* XXXKSE */ 838 if (error) 839 return (error); 840 841 /* 842 * 1) Check if file execution is disabled for the filesystem that this 843 * file resides on. 844 * 2) Insure that at least one execute bit is on - otherwise root 845 * will always succeed, and we don't want to happen unless the 846 * file really is executable. 847 * 3) Insure that the file is a regular file. 848 */ 849 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 850 ((attr->va_mode & 0111) == 0) || 851 (attr->va_type != VREG)) { 852 return (EACCES); 853 } 854 855 /* 856 * Zero length files can't be exec'd 857 */ 858 if (attr->va_size == 0) 859 return (ENOEXEC); 860 861 /* 862 * Check for execute permission to file based on current credentials. 863 */ 864 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, curthread); /* XXXKSE */ 865 if (error) 866 return (error); 867 868 /* 869 * Check number of open-for-writes on the file and deny execution 870 * if there are any. 871 */ 872 if (vp->v_writecount) 873 return (ETXTBSY); 874 875 /* 876 * Call filesystem specific open routine (which does nothing in the 877 * general case). 878 */ 879 error = VOP_OPEN(vp, FREAD, p->p_ucred, curthread); /* XXXKSE */ 880 if (error) 881 return (error); 882 883 return (0); 884 } 885 886 /* 887 * Exec handler registration 888 */ 889 int 890 exec_register(execsw_arg) 891 const struct execsw *execsw_arg; 892 { 893 const struct execsw **es, **xs, **newexecsw; 894 int count = 2; /* New slot and trailing NULL */ 895 896 if (execsw) 897 for (es = execsw; *es; es++) 898 count++; 899 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 900 if (newexecsw == NULL) 901 return ENOMEM; 902 xs = newexecsw; 903 if (execsw) 904 for (es = execsw; *es; es++) 905 *xs++ = *es; 906 *xs++ = execsw_arg; 907 *xs = NULL; 908 if (execsw) 909 free(execsw, M_TEMP); 910 execsw = newexecsw; 911 return 0; 912 } 913 914 int 915 exec_unregister(execsw_arg) 916 const struct execsw *execsw_arg; 917 { 918 const struct execsw **es, **xs, **newexecsw; 919 int count = 1; 920 921 if (execsw == NULL) 922 panic("unregister with no handlers left?\n"); 923 924 for (es = execsw; *es; es++) { 925 if (*es == execsw_arg) 926 break; 927 } 928 if (*es == NULL) 929 return ENOENT; 930 for (es = execsw; *es; es++) 931 if (*es != execsw_arg) 932 count++; 933 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 934 if (newexecsw == NULL) 935 return ENOMEM; 936 xs = newexecsw; 937 for (es = execsw; *es; es++) 938 if (*es != execsw_arg) 939 *xs++ = *es; 940 *xs = NULL; 941 if (execsw) 942 free(execsw, M_TEMP); 943 execsw = newexecsw; 944 return 0; 945 } 946 947 int 948 at_exec(function) 949 execlist_fn function; 950 { 951 struct execlist *ep; 952 953 #ifdef INVARIANTS 954 /* Be noisy if the programmer has lost track of things */ 955 if (rm_at_exec(function)) 956 printf("WARNING: exec callout entry (%p) already present\n", 957 function); 958 #endif 959 ep = malloc(sizeof(*ep), M_ATEXEC, M_NOWAIT); 960 if (ep == NULL) 961 return (ENOMEM); 962 ep->function = function; 963 TAILQ_INSERT_TAIL(&exec_list, ep, next); 964 return (0); 965 } 966 967 /* 968 * Scan the exec callout list for the given item and remove it. 969 * Returns the number of items removed (0 or 1) 970 */ 971 int 972 rm_at_exec(function) 973 execlist_fn function; 974 { 975 struct execlist *ep; 976 977 TAILQ_FOREACH(ep, &exec_list, next) { 978 if (ep->function == function) { 979 TAILQ_REMOVE(&exec_list, ep, next); 980 free(ep, M_ATEXEC); 981 return(1); 982 } 983 } 984 return (0); 985 } 986 987