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