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: src/sys/kern/kern_exec.c,v 1.107.2.15 2002/07/30 15:40:46 nectar Exp $ 27 * $DragonFly: src/sys/kern/kern_exec.c,v 1.27 2004/05/13 17:40:15 dillon Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/sysproto.h> 33 #include <sys/kernel.h> 34 #include <sys/mount.h> 35 #include <sys/filedesc.h> 36 #include <sys/fcntl.h> 37 #include <sys/acct.h> 38 #include <sys/exec.h> 39 #include <sys/imgact.h> 40 #include <sys/imgact_elf.h> 41 #include <sys/kern_syscall.h> 42 #include <sys/wait.h> 43 #include <sys/malloc.h> 44 #include <sys/proc.h> 45 #include <sys/signalvar.h> 46 #include <sys/pioctl.h> 47 #include <sys/namei.h> 48 #include <sys/sfbuf.h> 49 #include <sys/sysent.h> 50 #include <sys/shm.h> 51 #include <sys/sysctl.h> 52 #include <sys/vnode.h> 53 #include <sys/vmmeter.h> 54 #include <sys/aio.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_param.h> 58 #include <sys/lock.h> 59 #include <vm/pmap.h> 60 #include <vm/vm_page.h> 61 #include <vm/vm_map.h> 62 #include <vm/vm_kern.h> 63 #include <vm/vm_extern.h> 64 #include <vm/vm_object.h> 65 #include <vm/vm_pager.h> 66 67 #include <sys/user.h> 68 #include <machine/reg.h> 69 70 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 71 72 static register_t *exec_copyout_strings (struct image_params *); 73 74 /* XXX This should be vm_size_t. */ 75 static u_long ps_strings = PS_STRINGS; 76 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, ""); 77 78 /* XXX This should be vm_size_t. */ 79 static u_long usrstack = USRSTACK; 80 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, ""); 81 82 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 83 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 84 &ps_arg_cache_limit, 0, ""); 85 86 int ps_argsopen = 1; 87 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); 88 89 void print_execve_args(struct image_args *args); 90 int debug_execve_args = 0; 91 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args, 92 0, ""); 93 94 void 95 print_execve_args(struct image_args *args) 96 { 97 char *cp; 98 int ndx; 99 100 cp = args->begin_argv; 101 for (ndx = 0; ndx < args->argc; ndx++) { 102 printf("\targv[%d]: %s\n", ndx, cp); 103 while (*cp++ != '\0'); 104 } 105 for (ndx = 0; ndx < args->envc; ndx++) { 106 printf("\tenvv[%d]: %s\n", ndx, cp); 107 while (*cp++ != '\0'); 108 } 109 } 110 111 /* 112 * Each of the items is a pointer to a `const struct execsw', hence the 113 * double pointer here. 114 */ 115 static const struct execsw **execsw; 116 117 int 118 kern_execve(struct nameidata *ndp, struct image_args *args) 119 { 120 struct thread *td = curthread; 121 struct proc *p = td->td_proc; 122 register_t *stack_base; 123 int error, len, i; 124 struct image_params image_params, *imgp; 125 struct vattr attr; 126 int (*img_first) (struct image_params *); 127 128 if (debug_execve_args) { 129 printf("%s()\n", __func__); 130 print_execve_args(args); 131 } 132 133 KKASSERT(p); 134 imgp = &image_params; 135 136 /* 137 * Lock the process and set the P_INEXEC flag to indicate that 138 * it should be left alone until we're done here. This is 139 * necessary to avoid race conditions - e.g. in ptrace() - 140 * that might allow a local user to illicitly obtain elevated 141 * privileges. 142 */ 143 p->p_flag |= P_INEXEC; 144 145 /* 146 * Initialize part of the common data 147 */ 148 imgp->proc = p; 149 imgp->args = args; 150 imgp->attr = &attr; 151 imgp->entry_addr = 0; 152 imgp->resident = 0; 153 imgp->vmspace_destroyed = 0; 154 imgp->interpreted = 0; 155 imgp->interpreter_name[0] = 0; 156 imgp->auxargs = NULL; 157 imgp->vp = NULL; 158 imgp->firstpage = NULL; 159 imgp->ps_strings = 0; 160 imgp->image_header = NULL; 161 162 interpret: 163 164 /* 165 * Translate the file name. namei() returns a vnode pointer 166 * in ni_vp amoung other things. 167 */ 168 if ((error = namei(ndp)) != 0) 169 goto exec_fail; 170 171 imgp->vp = ndp->ni_vp; 172 173 /* 174 * Check file permissions (also 'opens' file) 175 */ 176 error = exec_check_permissions(imgp); 177 if (error) { 178 VOP_UNLOCK(imgp->vp, NULL, 0, td); 179 goto exec_fail_dealloc; 180 } 181 182 error = exec_map_first_page(imgp); 183 VOP_UNLOCK(imgp->vp, NULL, 0, td); 184 if (error) 185 goto exec_fail_dealloc; 186 187 if (debug_execve_args && imgp->interpreted) { 188 printf(" target is interpreted -- recursive pass\n"); 189 printf(" interpreter: %s\n", imgp->interpreter_name); 190 print_execve_args(args); 191 } 192 193 /* 194 * If the current process has a special image activator it 195 * wants to try first, call it. For example, emulating shell 196 * scripts differently. 197 */ 198 error = -1; 199 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 200 error = img_first(imgp); 201 202 /* 203 * If the vnode has a registered vmspace, exec the vmspace 204 */ 205 if (error == -1 && imgp->vp->v_resident) { 206 error = exec_resident_imgact(imgp); 207 } 208 209 /* 210 * Loop through the list of image activators, calling each one. 211 * An activator returns -1 if there is no match, 0 on success, 212 * and an error otherwise. 213 */ 214 for (i = 0; error == -1 && execsw[i]; ++i) { 215 if (execsw[i]->ex_imgact == NULL || 216 execsw[i]->ex_imgact == img_first) { 217 continue; 218 } 219 error = (*execsw[i]->ex_imgact)(imgp); 220 } 221 222 if (error) { 223 if (error == -1) 224 error = ENOEXEC; 225 goto exec_fail_dealloc; 226 } 227 228 /* 229 * Special interpreter operation, cleanup and loop up to try to 230 * activate the interpreter. 231 */ 232 if (imgp->interpreted) { 233 exec_unmap_first_page(imgp); 234 /* free name buffer and old vnode */ 235 NDFREE(ndp, NDF_ONLY_PNBUF); 236 vrele(ndp->ni_vp); 237 /* set new name to that of the interpreter */ 238 NDINIT(ndp, NAMEI_LOOKUP, 239 CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, 240 UIO_SYSSPACE, imgp->interpreter_name, td); 241 goto interpret; 242 } 243 244 /* 245 * Copy out strings (args and env) and initialize stack base 246 */ 247 stack_base = exec_copyout_strings(imgp); 248 p->p_vmspace->vm_minsaddr = (char *)stack_base; 249 250 /* 251 * If custom stack fixup routine present for this process 252 * let it do the stack setup. If we are running a resident 253 * image there is no auxinfo or other image activator context 254 * so don't try to add fixups to the stack. 255 * 256 * Else stuff argument count as first item on stack 257 */ 258 if (p->p_sysent->sv_fixup && imgp->resident == 0) 259 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 260 else 261 suword(--stack_base, imgp->args->argc); 262 263 /* 264 * For security and other reasons, the file descriptor table cannot 265 * be shared after an exec. 266 */ 267 if (p->p_fd->fd_refcnt > 1) { 268 struct filedesc *tmp; 269 270 tmp = fdcopy(p); 271 fdfree(p); 272 p->p_fd = tmp; 273 } 274 275 /* 276 * For security and other reasons, signal handlers cannot 277 * be shared after an exec. The new proces gets a copy of the old 278 * handlers. In execsigs(), the new process will have its signals 279 * reset. 280 */ 281 if (p->p_procsig->ps_refcnt > 1) { 282 struct procsig *newprocsig; 283 284 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), 285 M_SUBPROC, M_WAITOK); 286 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig)); 287 p->p_procsig->ps_refcnt--; 288 p->p_procsig = newprocsig; 289 p->p_procsig->ps_refcnt = 1; 290 if (p->p_sigacts == &p->p_addr->u_sigacts) 291 panic("shared procsig but private sigacts?"); 292 293 p->p_addr->u_sigacts = *p->p_sigacts; 294 p->p_sigacts = &p->p_addr->u_sigacts; 295 } 296 297 /* Stop profiling */ 298 stopprofclock(p); 299 300 /* close files on exec */ 301 fdcloseexec(p); 302 303 /* reset caught signals */ 304 execsigs(p); 305 306 /* name this process - nameiexec(p, ndp) */ 307 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 308 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 309 p->p_comm[len] = 0; 310 311 /* 312 * mark as execed, wakeup the process that vforked (if any) and tell 313 * it that it now has its own resources back 314 */ 315 p->p_flag |= P_EXEC; 316 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 317 p->p_flag &= ~P_PPWAIT; 318 wakeup((caddr_t)p->p_pptr); 319 } 320 321 /* 322 * Implement image setuid/setgid. 323 * 324 * Don't honor setuid/setgid if the filesystem prohibits it or if 325 * the process is being traced. 326 */ 327 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) || 328 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) && 329 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 330 (p->p_flag & P_TRACED) == 0) { 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(); 337 if (p->p_tracep && suser(td)) { 338 struct vnode *vtmp; 339 340 if ((vtmp = p->p_tracep) != NULL) { 341 p->p_tracep = NULL; 342 p->p_traceflag = 0; 343 vrele(vtmp); 344 } 345 } 346 /* Close any file descriptors 0..2 that reference procfs */ 347 setugidsafety(p); 348 /* Make sure file descriptors 0..2 are in use. */ 349 error = fdcheckstd(p); 350 if (error != 0) 351 goto exec_fail_dealloc; 352 /* 353 * Set the new credentials. 354 */ 355 cratom(&p->p_ucred); 356 if (attr.va_mode & VSUID) 357 change_euid(attr.va_uid); 358 if (attr.va_mode & VSGID) 359 p->p_ucred->cr_gid = attr.va_gid; 360 361 /* 362 * Clear local varsym variables 363 */ 364 varsymset_clean(&p->p_varsymset); 365 } else { 366 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid && 367 p->p_ucred->cr_gid == p->p_ucred->cr_rgid) 368 p->p_flag &= ~P_SUGID; 369 } 370 371 /* 372 * Implement correct POSIX saved-id behavior. 373 */ 374 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid || 375 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) { 376 cratom(&p->p_ucred); 377 p->p_ucred->cr_svuid = p->p_ucred->cr_uid; 378 p->p_ucred->cr_svgid = p->p_ucred->cr_gid; 379 } 380 381 /* 382 * Store the vp for use in procfs 383 */ 384 if (p->p_textvp) /* release old reference */ 385 vrele(p->p_textvp); 386 vref(ndp->ni_vp); 387 p->p_textvp = ndp->ni_vp; 388 389 /* 390 * Notify others that we exec'd, and clear the P_INEXEC flag 391 * as we're now a bona fide freshly-execed process. 392 */ 393 KNOTE(&p->p_klist, NOTE_EXEC); 394 p->p_flag &= ~P_INEXEC; 395 396 /* 397 * If tracing the process, trap to debugger so breakpoints 398 * can be set before the program executes. 399 */ 400 STOPEVENT(p, S_EXEC, 0); 401 402 if (p->p_flag & P_TRACED) 403 psignal(p, SIGTRAP); 404 405 /* clear "fork but no exec" flag, as we _are_ execing */ 406 p->p_acflag &= ~AFORK; 407 408 /* Set values passed into the program in registers. */ 409 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base, 410 imgp->ps_strings); 411 412 /* Free any previous argument cache */ 413 if (p->p_args && --p->p_args->ar_ref == 0) 414 FREE(p->p_args, M_PARGS); 415 p->p_args = NULL; 416 417 /* Cache arguments if they fit inside our allowance */ 418 i = imgp->args->begin_envv - imgp->args->begin_argv; 419 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 420 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i, 421 M_PARGS, M_WAITOK); 422 p->p_args->ar_ref = 1; 423 p->p_args->ar_length = i; 424 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i); 425 } 426 427 exec_fail_dealloc: 428 429 /* 430 * free various allocated resources 431 */ 432 if (imgp->firstpage) 433 exec_unmap_first_page(imgp); 434 435 if (imgp->vp) { 436 NDFREE(ndp, NDF_ONLY_PNBUF); 437 vrele(imgp->vp); 438 } 439 440 if (error == 0) { 441 ++mycpu->gd_cnt.v_exec; 442 return (0); 443 } 444 445 exec_fail: 446 /* we're done here, clear P_INEXEC */ 447 p->p_flag &= ~P_INEXEC; 448 if (imgp->vmspace_destroyed) { 449 /* sorry, no more process anymore. exit gracefully */ 450 exit1(W_EXITCODE(0, SIGABRT)); 451 /* NOT REACHED */ 452 return(0); 453 } else { 454 return(error); 455 } 456 } 457 458 /* 459 * execve() system call. 460 */ 461 int 462 execve(struct execve_args *uap) 463 { 464 struct thread *td = curthread; 465 struct nameidata nd; 466 struct image_args args; 467 int error; 468 469 NDINIT(&nd, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, 470 UIO_USERSPACE, uap->fname, td); 471 472 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE, 473 uap->argv, uap->envv); 474 if (error == 0) 475 error = kern_execve(&nd, &args); 476 477 exec_free_args(&args); 478 479 /* 480 * The syscall result is returned in registers to the new program. 481 * Linux will register %edx as an atexit function and we must be 482 * sure to set it to 0. XXX 483 */ 484 if (error == 0) 485 uap->sysmsg_result64 = 0; 486 487 return (error); 488 } 489 490 int 491 exec_map_first_page(struct image_params *imgp) 492 { 493 int s, rv, i; 494 int initial_pagein; 495 vm_page_t ma[VM_INITIAL_PAGEIN]; 496 vm_page_t m; 497 vm_object_t object; 498 499 if (imgp->firstpage) 500 exec_unmap_first_page(imgp); 501 502 VOP_GETVOBJECT(imgp->vp, &object); 503 504 /* 505 * We shouldn't need protection for vm_page_grab() but we certainly 506 * need it for the lookup loop below (lookup/busy race), since 507 * an interrupt can unbusy and free the page before our busy check. 508 */ 509 s = splvm(); 510 m = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 511 512 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 513 ma[0] = m; 514 initial_pagein = VM_INITIAL_PAGEIN; 515 if (initial_pagein > object->size) 516 initial_pagein = object->size; 517 for (i = 1; i < initial_pagein; i++) { 518 if ((m = vm_page_lookup(object, i)) != NULL) { 519 if ((m->flags & PG_BUSY) || m->busy) 520 break; 521 if (m->valid) 522 break; 523 vm_page_busy(m); 524 } else { 525 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL); 526 if (m == NULL) 527 break; 528 } 529 ma[i] = m; 530 } 531 initial_pagein = i; 532 533 /* 534 * get_pages unbusies all the requested pages except the 535 * primary page (at index 0 in this case). 536 */ 537 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 538 m = vm_page_lookup(object, 0); 539 540 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) { 541 if (m) { 542 vm_page_protect(m, VM_PROT_NONE); 543 vm_page_free(m); 544 } 545 splx(s); 546 return EIO; 547 } 548 } 549 vm_page_hold(m); 550 vm_page_wakeup(m); /* unbusy the page */ 551 splx(s); 552 553 imgp->firstpage = sf_buf_alloc(m, SFBA_QUICK); 554 imgp->image_header = (void *)sf_buf_kva(imgp->firstpage); 555 556 return 0; 557 } 558 559 void 560 exec_unmap_first_page(imgp) 561 struct image_params *imgp; 562 { 563 vm_page_t m; 564 int s; 565 566 s = splvm(); 567 if (imgp->firstpage != NULL) { 568 m = sf_buf_page(imgp->firstpage); 569 sf_buf_free(imgp->firstpage); 570 imgp->firstpage = NULL; 571 imgp->image_header = NULL; 572 vm_page_unhold(m); 573 } 574 splx(s); 575 } 576 577 /* 578 * Destroy old address space, and allocate a new stack 579 * The new stack is only SGROWSIZ large because it is grown 580 * automatically in trap.c. 581 */ 582 int 583 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy) 584 { 585 int error; 586 struct vmspace *vmspace = imgp->proc->p_vmspace; 587 vm_offset_t stack_addr = USRSTACK - maxssiz; 588 vm_map_t map; 589 590 imgp->vmspace_destroyed = 1; 591 592 /* 593 * Prevent a pending AIO from modifying the new address space. 594 */ 595 aio_proc_rundown(imgp->proc); 596 597 /* 598 * Blow away entire process VM, if address space not shared, 599 * otherwise, create a new VM space so that other threads are 600 * not disrupted. If we are execing a resident vmspace we 601 * create a duplicate of it and remap the stack. 602 * 603 * The exitingcnt test is not strictly necessary but has been 604 * included for code sanity (to make the code more deterministic). 605 */ 606 map = &vmspace->vm_map; 607 if (vmcopy) { 608 vmspace_exec(imgp->proc, vmcopy); 609 vmspace = imgp->proc->p_vmspace; 610 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK); 611 map = &vmspace->vm_map; 612 } else if (vmspace->vm_refcnt == 1 && vmspace->vm_exitingcnt == 0) { 613 shmexit(vmspace); 614 if (vmspace->vm_upcalls) 615 upc_release(vmspace, imgp->proc); 616 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS); 617 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS); 618 } else { 619 vmspace_exec(imgp->proc, NULL); 620 vmspace = imgp->proc->p_vmspace; 621 map = &vmspace->vm_map; 622 } 623 624 /* Allocate a new stack */ 625 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz, 626 VM_PROT_ALL, VM_PROT_ALL, 0); 627 if (error) 628 return (error); 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_copyin_args(struct image_args *args, char *fname, 646 enum exec_path_segflg segflg, char **argv, char **envv) 647 { 648 char *argp, *envp; 649 int error = 0; 650 size_t length; 651 652 bzero(args, sizeof(*args)); 653 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX); 654 if (args->buf == NULL) 655 return (ENOMEM); 656 args->begin_argv = args->buf; 657 args->endp = args->begin_argv; 658 args->space = ARG_MAX; 659 660 args->fname = args->buf + ARG_MAX; 661 662 /* 663 * Copy the file name. 664 */ 665 if (segflg == PATH_SYSSPACE) { 666 error = copystr(fname, args->fname, PATH_MAX, &length); 667 } else if (segflg == PATH_USERSPACE) { 668 error = copyinstr(fname, args->fname, PATH_MAX, &length); 669 } 670 671 /* 672 * extract argument strings 673 */ 674 675 if (argv && error == 0) { 676 /* 677 * The argv0 argument for execv() is allowed to be NULL, 678 * in which case we use our filename as argv[0]. 679 * This guarantees that 680 * the interpreter knows what file to open in the case 681 * that we exec an interpreted file. 682 */ 683 argp = (caddr_t) (intptr_t) fuword(argv); 684 if (argp == NULL) { 685 length = strlen(args->fname) + 1; 686 KKASSERT(length <= args->space); 687 bcopy(args->fname, args->endp, length); 688 args->space -= length; 689 args->endp += length; 690 args->argc++; 691 argv++; 692 } 693 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 694 if (argp == (caddr_t) -1) { 695 error = EFAULT; 696 goto cleanup; 697 } 698 error = copyinstr(argp, args->endp, 699 args->space, &length); 700 if (error == ENAMETOOLONG) 701 error = E2BIG; 702 if (error) 703 goto cleanup; 704 args->space -= length; 705 args->endp += length; 706 args->argc++; 707 } 708 } 709 710 args->begin_envv = args->endp; 711 712 /* 713 * extract environment strings 714 */ 715 if (envv && error == 0) { 716 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) { 717 if (envp == (caddr_t) -1) { 718 error = EFAULT; 719 goto cleanup; 720 } 721 error = copyinstr(envp, args->endp, args->space, 722 &length); 723 if (error == ENAMETOOLONG) 724 error = E2BIG; 725 if (error) 726 goto cleanup; 727 args->space -= length; 728 args->endp += length; 729 args->envc++; 730 } 731 } 732 733 cleanup: 734 return (error); 735 } 736 737 void 738 exec_free_args(struct image_args *args) 739 { 740 if (args->buf) { 741 kmem_free_wakeup(exec_map, 742 (vm_offset_t)args->buf, PATH_MAX + ARG_MAX); 743 args->buf = NULL; 744 } 745 } 746 747 /* 748 * Copy strings out to the new process address space, constructing 749 * new arg and env vector tables. Return a pointer to the base 750 * so that it can be used as the initial stack pointer. 751 */ 752 register_t * 753 exec_copyout_strings(struct image_params *imgp) 754 { 755 int argc, envc; 756 char **vectp; 757 char *stringp, *destp; 758 register_t *stack_base; 759 struct ps_strings *arginfo; 760 int szsigcode; 761 762 /* 763 * Calculate string base and vector table pointers. 764 * Also deal with signal trampoline code for this exec type. 765 */ 766 arginfo = (struct ps_strings *)PS_STRINGS; 767 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); 768 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 769 roundup((ARG_MAX - imgp->args->space), sizeof(char *)); 770 771 /* 772 * install sigcode 773 */ 774 if (szsigcode) 775 copyout(imgp->proc->p_sysent->sv_sigcode, 776 ((caddr_t)arginfo - szsigcode), szsigcode); 777 778 /* 779 * If we have a valid auxargs ptr, prepare some room 780 * on the stack. 781 * 782 * The '+ 2' is for the null pointers at the end of each of the 783 * arg and env vector sets, and 'AT_COUNT*2' is room for the 784 * ELF Auxargs data. 785 */ 786 if (imgp->auxargs) { 787 vectp = (char **)(destp - (imgp->args->argc + 788 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*)); 789 } else { 790 vectp = (char **)(destp - (imgp->args->argc + 791 imgp->args->envc + 2) * sizeof(char*)); 792 } 793 794 /* 795 * NOTE: don't bother aligning the stack here for GCC 2.x, it will 796 * be done in crt1.o. Note that GCC 3.x aligns the stack in main. 797 */ 798 799 /* 800 * vectp also becomes our initial stack base 801 */ 802 stack_base = (register_t *)vectp; 803 804 stringp = imgp->args->begin_argv; 805 argc = imgp->args->argc; 806 envc = imgp->args->envc; 807 808 /* 809 * Copy out strings - arguments and environment. 810 */ 811 copyout(stringp, destp, ARG_MAX - imgp->args->space); 812 813 /* 814 * Fill in "ps_strings" struct for ps, w, etc. 815 */ 816 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 817 suword(&arginfo->ps_nargvstr, argc); 818 819 /* 820 * Fill in argument portion of vector table. 821 */ 822 for (; argc > 0; --argc) { 823 suword(vectp++, (long)(intptr_t)destp); 824 while (*stringp++ != 0) 825 destp++; 826 destp++; 827 } 828 829 /* a null vector table pointer separates the argp's from the envp's */ 830 suword(vectp++, 0); 831 832 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 833 suword(&arginfo->ps_nenvstr, envc); 834 835 /* 836 * Fill in environment portion of vector table. 837 */ 838 for (; envc > 0; --envc) { 839 suword(vectp++, (long)(intptr_t)destp); 840 while (*stringp++ != 0) 841 destp++; 842 destp++; 843 } 844 845 /* end of vector table is a null pointer */ 846 suword(vectp, 0); 847 848 return (stack_base); 849 } 850 851 /* 852 * Check permissions of file to execute. 853 * Return 0 for success or error code on failure. 854 */ 855 int 856 exec_check_permissions(imgp) 857 struct image_params *imgp; 858 { 859 struct proc *p = imgp->proc; 860 struct vnode *vp = imgp->vp; 861 struct vattr *attr = imgp->attr; 862 struct thread *td = p->p_thread; 863 int error; 864 865 /* Get file attributes */ 866 error = VOP_GETATTR(vp, attr, td); 867 if (error) 868 return (error); 869 870 /* 871 * 1) Check if file execution is disabled for the filesystem that this 872 * file resides on. 873 * 2) Insure that at least one execute bit is on - otherwise root 874 * will always succeed, and we don't want to happen unless the 875 * file really is executable. 876 * 3) Insure that the file is a regular file. 877 */ 878 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 879 ((attr->va_mode & 0111) == 0) || 880 (attr->va_type != VREG)) { 881 return (EACCES); 882 } 883 884 /* 885 * Zero length files can't be exec'd 886 */ 887 if (attr->va_size == 0) 888 return (ENOEXEC); 889 890 /* 891 * Check for execute permission to file based on current credentials. 892 */ 893 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td); 894 if (error) 895 return (error); 896 897 /* 898 * Check number of open-for-writes on the file and deny execution 899 * if there are any. 900 */ 901 if (vp->v_writecount) 902 return (ETXTBSY); 903 904 /* 905 * Call filesystem specific open routine (which does nothing in the 906 * general case). 907 */ 908 error = VOP_OPEN(vp, FREAD, p->p_ucred, td); 909 if (error) 910 return (error); 911 912 return (0); 913 } 914 915 /* 916 * Exec handler registration 917 */ 918 int 919 exec_register(execsw_arg) 920 const struct execsw *execsw_arg; 921 { 922 const struct execsw **es, **xs, **newexecsw; 923 int count = 2; /* New slot and trailing NULL */ 924 925 if (execsw) 926 for (es = execsw; *es; es++) 927 count++; 928 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 929 if (newexecsw == NULL) 930 return ENOMEM; 931 xs = newexecsw; 932 if (execsw) 933 for (es = execsw; *es; es++) 934 *xs++ = *es; 935 *xs++ = execsw_arg; 936 *xs = NULL; 937 if (execsw) 938 free(execsw, M_TEMP); 939 execsw = newexecsw; 940 return 0; 941 } 942 943 int 944 exec_unregister(execsw_arg) 945 const struct execsw *execsw_arg; 946 { 947 const struct execsw **es, **xs, **newexecsw; 948 int count = 1; 949 950 if (execsw == NULL) 951 panic("unregister with no handlers left?"); 952 953 for (es = execsw; *es; es++) { 954 if (*es == execsw_arg) 955 break; 956 } 957 if (*es == NULL) 958 return ENOENT; 959 for (es = execsw; *es; es++) 960 if (*es != execsw_arg) 961 count++; 962 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 963 if (newexecsw == NULL) 964 return ENOMEM; 965 xs = newexecsw; 966 for (es = execsw; *es; es++) 967 if (*es != execsw_arg) 968 *xs++ = *es; 969 *xs = NULL; 970 if (execsw) 971 free(execsw, M_TEMP); 972 execsw = newexecsw; 973 return 0; 974 } 975