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 1.28 2004/10/12 19:20:46 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 #include <sys/thread2.h> 71 72 MALLOC_DEFINE(M_PARGS, "proc-args", "Process arguments"); 73 74 static register_t *exec_copyout_strings (struct image_params *); 75 76 /* XXX This should be vm_size_t. */ 77 static u_long ps_strings = PS_STRINGS; 78 SYSCTL_ULONG(_kern, KERN_PS_STRINGS, ps_strings, CTLFLAG_RD, &ps_strings, 0, ""); 79 80 /* XXX This should be vm_size_t. */ 81 static u_long usrstack = USRSTACK; 82 SYSCTL_ULONG(_kern, KERN_USRSTACK, usrstack, CTLFLAG_RD, &usrstack, 0, ""); 83 84 u_long ps_arg_cache_limit = PAGE_SIZE / 16; 85 SYSCTL_LONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 86 &ps_arg_cache_limit, 0, ""); 87 88 int ps_argsopen = 1; 89 SYSCTL_INT(_kern, OID_AUTO, ps_argsopen, CTLFLAG_RW, &ps_argsopen, 0, ""); 90 91 void print_execve_args(struct image_args *args); 92 int debug_execve_args = 0; 93 SYSCTL_INT(_kern, OID_AUTO, debug_execve_args, CTLFLAG_RW, &debug_execve_args, 94 0, ""); 95 96 void 97 print_execve_args(struct image_args *args) 98 { 99 char *cp; 100 int ndx; 101 102 cp = args->begin_argv; 103 for (ndx = 0; ndx < args->argc; ndx++) { 104 printf("\targv[%d]: %s\n", ndx, cp); 105 while (*cp++ != '\0'); 106 } 107 for (ndx = 0; ndx < args->envc; ndx++) { 108 printf("\tenvv[%d]: %s\n", ndx, cp); 109 while (*cp++ != '\0'); 110 } 111 } 112 113 /* 114 * Each of the items is a pointer to a `const struct execsw', hence the 115 * double pointer here. 116 */ 117 static const struct execsw **execsw; 118 119 int 120 kern_execve(struct nameidata *ndp, struct image_args *args) 121 { 122 struct thread *td = curthread; 123 struct proc *p = td->td_proc; 124 register_t *stack_base; 125 int error, len, i; 126 struct image_params image_params, *imgp; 127 struct vattr attr; 128 int (*img_first) (struct image_params *); 129 130 if (debug_execve_args) { 131 printf("%s()\n", __func__); 132 print_execve_args(args); 133 } 134 135 KKASSERT(p); 136 imgp = &image_params; 137 138 /* 139 * Lock the process and set the P_INEXEC flag to indicate that 140 * it should be left alone until we're done here. This is 141 * necessary to avoid race conditions - e.g. in ptrace() - 142 * that might allow a local user to illicitly obtain elevated 143 * privileges. 144 */ 145 p->p_flag |= P_INEXEC; 146 147 /* 148 * Initialize part of the common data 149 */ 150 imgp->proc = p; 151 imgp->args = args; 152 imgp->attr = &attr; 153 imgp->entry_addr = 0; 154 imgp->resident = 0; 155 imgp->vmspace_destroyed = 0; 156 imgp->interpreted = 0; 157 imgp->interpreter_name[0] = 0; 158 imgp->auxargs = NULL; 159 imgp->vp = NULL; 160 imgp->firstpage = NULL; 161 imgp->ps_strings = 0; 162 imgp->image_header = NULL; 163 164 interpret: 165 166 /* 167 * Translate the file name. namei() returns a vnode pointer 168 * in ni_vp amoung other things. 169 */ 170 if ((error = namei(ndp)) != 0) 171 goto exec_fail; 172 173 imgp->vp = ndp->ni_vp; 174 175 /* 176 * Check file permissions (also 'opens' file) 177 */ 178 error = exec_check_permissions(imgp); 179 if (error) { 180 VOP_UNLOCK(imgp->vp, 0, td); 181 goto exec_fail_dealloc; 182 } 183 184 error = exec_map_first_page(imgp); 185 VOP_UNLOCK(imgp->vp, 0, td); 186 if (error) 187 goto exec_fail_dealloc; 188 189 if (debug_execve_args && imgp->interpreted) { 190 printf(" target is interpreted -- recursive pass\n"); 191 printf(" interpreter: %s\n", imgp->interpreter_name); 192 print_execve_args(args); 193 } 194 195 /* 196 * If the current process has a special image activator it 197 * wants to try first, call it. For example, emulating shell 198 * scripts differently. 199 */ 200 error = -1; 201 if ((img_first = imgp->proc->p_sysent->sv_imgact_try) != NULL) 202 error = img_first(imgp); 203 204 /* 205 * If the vnode has a registered vmspace, exec the vmspace 206 */ 207 if (error == -1 && imgp->vp->v_resident) { 208 error = exec_resident_imgact(imgp); 209 } 210 211 /* 212 * Loop through the list of image activators, calling each one. 213 * An activator returns -1 if there is no match, 0 on success, 214 * and an error otherwise. 215 */ 216 for (i = 0; error == -1 && execsw[i]; ++i) { 217 if (execsw[i]->ex_imgact == NULL || 218 execsw[i]->ex_imgact == img_first) { 219 continue; 220 } 221 error = (*execsw[i]->ex_imgact)(imgp); 222 } 223 224 if (error) { 225 if (error == -1) 226 error = ENOEXEC; 227 goto exec_fail_dealloc; 228 } 229 230 /* 231 * Special interpreter operation, cleanup and loop up to try to 232 * activate the interpreter. 233 */ 234 if (imgp->interpreted) { 235 exec_unmap_first_page(imgp); 236 /* free name buffer and old vnode */ 237 NDFREE(ndp, NDF_ONLY_PNBUF); 238 vrele(ndp->ni_vp); 239 /* set new name to that of the interpreter */ 240 NDINIT(ndp, NAMEI_LOOKUP, 241 CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, 242 UIO_SYSSPACE, imgp->interpreter_name, td); 243 goto interpret; 244 } 245 246 /* 247 * Copy out strings (args and env) and initialize stack base 248 */ 249 stack_base = exec_copyout_strings(imgp); 250 p->p_vmspace->vm_minsaddr = (char *)stack_base; 251 252 /* 253 * If custom stack fixup routine present for this process 254 * let it do the stack setup. If we are running a resident 255 * image there is no auxinfo or other image activator context 256 * so don't try to add fixups to the stack. 257 * 258 * Else stuff argument count as first item on stack 259 */ 260 if (p->p_sysent->sv_fixup && imgp->resident == 0) 261 (*p->p_sysent->sv_fixup)(&stack_base, imgp); 262 else 263 suword(--stack_base, imgp->args->argc); 264 265 /* 266 * For security and other reasons, the file descriptor table cannot 267 * be shared after an exec. 268 */ 269 if (p->p_fd->fd_refcnt > 1) { 270 struct filedesc *tmp; 271 272 tmp = fdcopy(p); 273 fdfree(p); 274 p->p_fd = tmp; 275 } 276 277 /* 278 * For security and other reasons, signal handlers cannot 279 * be shared after an exec. The new proces gets a copy of the old 280 * handlers. In execsigs(), the new process will have its signals 281 * reset. 282 */ 283 if (p->p_procsig->ps_refcnt > 1) { 284 struct procsig *newprocsig; 285 286 MALLOC(newprocsig, struct procsig *, sizeof(struct procsig), 287 M_SUBPROC, M_WAITOK); 288 bcopy(p->p_procsig, newprocsig, sizeof(*newprocsig)); 289 p->p_procsig->ps_refcnt--; 290 p->p_procsig = newprocsig; 291 p->p_procsig->ps_refcnt = 1; 292 if (p->p_sigacts == &p->p_addr->u_sigacts) 293 panic("shared procsig but private sigacts?"); 294 295 p->p_addr->u_sigacts = *p->p_sigacts; 296 p->p_sigacts = &p->p_addr->u_sigacts; 297 } 298 299 /* Stop profiling */ 300 stopprofclock(p); 301 302 /* close files on exec */ 303 fdcloseexec(p); 304 305 /* reset caught signals */ 306 execsigs(p); 307 308 /* name this process - nameiexec(p, ndp) */ 309 len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN); 310 bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len); 311 p->p_comm[len] = 0; 312 313 /* 314 * mark as execed, wakeup the process that vforked (if any) and tell 315 * it that it now has its own resources back 316 */ 317 p->p_flag |= P_EXEC; 318 if (p->p_pptr && (p->p_flag & P_PPWAIT)) { 319 p->p_flag &= ~P_PPWAIT; 320 wakeup((caddr_t)p->p_pptr); 321 } 322 323 /* 324 * Implement image setuid/setgid. 325 * 326 * Don't honor setuid/setgid if the filesystem prohibits it or if 327 * the process is being traced. 328 */ 329 if ((((attr.va_mode & VSUID) && p->p_ucred->cr_uid != attr.va_uid) || 330 ((attr.va_mode & VSGID) && p->p_ucred->cr_gid != attr.va_gid)) && 331 (imgp->vp->v_mount->mnt_flag & MNT_NOSUID) == 0 && 332 (p->p_flag & P_TRACED) == 0) { 333 /* 334 * Turn off syscall tracing for set-id programs, except for 335 * root. Record any set-id flags first to make sure that 336 * we do not regain any tracing during a possible block. 337 */ 338 setsugid(); 339 if (p->p_tracep && suser(td)) { 340 struct vnode *vtmp; 341 342 if ((vtmp = p->p_tracep) != NULL) { 343 p->p_tracep = NULL; 344 p->p_traceflag = 0; 345 vrele(vtmp); 346 } 347 } 348 /* Close any file descriptors 0..2 that reference procfs */ 349 setugidsafety(p); 350 /* Make sure file descriptors 0..2 are in use. */ 351 error = fdcheckstd(p); 352 if (error != 0) 353 goto exec_fail_dealloc; 354 /* 355 * Set the new credentials. 356 */ 357 cratom(&p->p_ucred); 358 if (attr.va_mode & VSUID) 359 change_euid(attr.va_uid); 360 if (attr.va_mode & VSGID) 361 p->p_ucred->cr_gid = attr.va_gid; 362 363 /* 364 * Clear local varsym variables 365 */ 366 varsymset_clean(&p->p_varsymset); 367 } else { 368 if (p->p_ucred->cr_uid == p->p_ucred->cr_ruid && 369 p->p_ucred->cr_gid == p->p_ucred->cr_rgid) 370 p->p_flag &= ~P_SUGID; 371 } 372 373 /* 374 * Implement correct POSIX saved-id behavior. 375 */ 376 if (p->p_ucred->cr_svuid != p->p_ucred->cr_uid || 377 p->p_ucred->cr_svgid != p->p_ucred->cr_gid) { 378 cratom(&p->p_ucred); 379 p->p_ucred->cr_svuid = p->p_ucred->cr_uid; 380 p->p_ucred->cr_svgid = p->p_ucred->cr_gid; 381 } 382 383 /* 384 * Store the vp for use in procfs 385 */ 386 if (p->p_textvp) /* release old reference */ 387 vrele(p->p_textvp); 388 vref(ndp->ni_vp); 389 p->p_textvp = ndp->ni_vp; 390 391 /* 392 * Notify others that we exec'd, and clear the P_INEXEC flag 393 * as we're now a bona fide freshly-execed process. 394 */ 395 KNOTE(&p->p_klist, NOTE_EXEC); 396 p->p_flag &= ~P_INEXEC; 397 398 /* 399 * If tracing the process, trap to debugger so breakpoints 400 * can be set before the program executes. 401 */ 402 STOPEVENT(p, S_EXEC, 0); 403 404 if (p->p_flag & P_TRACED) 405 psignal(p, SIGTRAP); 406 407 /* clear "fork but no exec" flag, as we _are_ execing */ 408 p->p_acflag &= ~AFORK; 409 410 /* Set values passed into the program in registers. */ 411 setregs(p, imgp->entry_addr, (u_long)(uintptr_t)stack_base, 412 imgp->ps_strings); 413 414 /* Free any previous argument cache */ 415 if (p->p_args && --p->p_args->ar_ref == 0) 416 FREE(p->p_args, M_PARGS); 417 p->p_args = NULL; 418 419 /* Cache arguments if they fit inside our allowance */ 420 i = imgp->args->begin_envv - imgp->args->begin_argv; 421 if (ps_arg_cache_limit >= i + sizeof(struct pargs)) { 422 MALLOC(p->p_args, struct pargs *, sizeof(struct pargs) + i, 423 M_PARGS, M_WAITOK); 424 p->p_args->ar_ref = 1; 425 p->p_args->ar_length = i; 426 bcopy(imgp->args->begin_argv, p->p_args->ar_args, i); 427 } 428 429 exec_fail_dealloc: 430 431 /* 432 * free various allocated resources 433 */ 434 if (imgp->firstpage) 435 exec_unmap_first_page(imgp); 436 437 if (imgp->vp) { 438 NDFREE(ndp, NDF_ONLY_PNBUF); 439 vrele(imgp->vp); 440 } 441 442 if (error == 0) { 443 ++mycpu->gd_cnt.v_exec; 444 return (0); 445 } 446 447 exec_fail: 448 /* we're done here, clear P_INEXEC */ 449 p->p_flag &= ~P_INEXEC; 450 if (imgp->vmspace_destroyed) { 451 /* sorry, no more process anymore. exit gracefully */ 452 exit1(W_EXITCODE(0, SIGABRT)); 453 /* NOT REACHED */ 454 return(0); 455 } else { 456 return(error); 457 } 458 } 459 460 /* 461 * execve() system call. 462 */ 463 int 464 execve(struct execve_args *uap) 465 { 466 struct thread *td = curthread; 467 struct nameidata nd; 468 struct image_args args; 469 int error; 470 471 NDINIT(&nd, NAMEI_LOOKUP, CNP_LOCKLEAF | CNP_FOLLOW | CNP_SAVENAME, 472 UIO_USERSPACE, uap->fname, td); 473 474 error = exec_copyin_args(&args, uap->fname, PATH_USERSPACE, 475 uap->argv, uap->envv); 476 if (error == 0) 477 error = kern_execve(&nd, &args); 478 479 exec_free_args(&args); 480 481 /* 482 * The syscall result is returned in registers to the new program. 483 * Linux will register %edx as an atexit function and we must be 484 * sure to set it to 0. XXX 485 */ 486 if (error == 0) 487 uap->sysmsg_result64 = 0; 488 489 return (error); 490 } 491 492 int 493 exec_map_first_page(struct image_params *imgp) 494 { 495 int rv, i; 496 int initial_pagein; 497 vm_page_t ma[VM_INITIAL_PAGEIN]; 498 vm_page_t m; 499 vm_object_t object; 500 501 if (imgp->firstpage) 502 exec_unmap_first_page(imgp); 503 504 VOP_GETVOBJECT(imgp->vp, &object); 505 506 /* 507 * We shouldn't need protection for vm_page_grab() but we certainly 508 * need it for the lookup loop below (lookup/busy race), since 509 * an interrupt can unbusy and free the page before our busy check. 510 */ 511 crit_enter(); 512 m = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 513 514 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 515 ma[0] = m; 516 initial_pagein = VM_INITIAL_PAGEIN; 517 if (initial_pagein > object->size) 518 initial_pagein = object->size; 519 for (i = 1; i < initial_pagein; i++) { 520 if ((m = vm_page_lookup(object, i)) != NULL) { 521 if ((m->flags & PG_BUSY) || m->busy) 522 break; 523 if (m->valid) 524 break; 525 vm_page_busy(m); 526 } else { 527 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL); 528 if (m == NULL) 529 break; 530 } 531 ma[i] = m; 532 } 533 initial_pagein = i; 534 535 /* 536 * get_pages unbusies all the requested pages except the 537 * primary page (at index 0 in this case). 538 */ 539 rv = vm_pager_get_pages(object, ma, initial_pagein, 0); 540 m = vm_page_lookup(object, 0); 541 542 if (rv != VM_PAGER_OK || m == NULL || m->valid == 0) { 543 if (m) { 544 vm_page_protect(m, VM_PROT_NONE); 545 vm_page_free(m); 546 } 547 crit_exit(); 548 return EIO; 549 } 550 } 551 vm_page_hold(m); 552 vm_page_wakeup(m); /* unbusy the page */ 553 crit_exit(); 554 555 imgp->firstpage = sf_buf_alloc(m, SFBA_QUICK); 556 imgp->image_header = (void *)sf_buf_kva(imgp->firstpage); 557 558 return 0; 559 } 560 561 void 562 exec_unmap_first_page(imgp) 563 struct image_params *imgp; 564 { 565 vm_page_t m; 566 567 crit_enter(); 568 if (imgp->firstpage != NULL) { 569 m = sf_buf_page(imgp->firstpage); 570 sf_buf_free(imgp->firstpage); 571 imgp->firstpage = NULL; 572 imgp->image_header = NULL; 573 vm_page_unhold(m); 574 } 575 crit_exit(); 576 } 577 578 /* 579 * Destroy old address space, and allocate a new stack 580 * The new stack is only SGROWSIZ large because it is grown 581 * automatically in trap.c. 582 */ 583 int 584 exec_new_vmspace(struct image_params *imgp, struct vmspace *vmcopy) 585 { 586 int error; 587 struct vmspace *vmspace = imgp->proc->p_vmspace; 588 vm_offset_t stack_addr = USRSTACK - maxssiz; 589 vm_map_t map; 590 591 imgp->vmspace_destroyed = 1; 592 593 /* 594 * Prevent a pending AIO from modifying the new address space. 595 */ 596 aio_proc_rundown(imgp->proc); 597 598 /* 599 * Blow away entire process VM, if address space not shared, 600 * otherwise, create a new VM space so that other threads are 601 * not disrupted. If we are execing a resident vmspace we 602 * create a duplicate of it and remap the stack. 603 * 604 * The exitingcnt test is not strictly necessary but has been 605 * included for code sanity (to make the code more deterministic). 606 */ 607 map = &vmspace->vm_map; 608 if (vmcopy) { 609 vmspace_exec(imgp->proc, vmcopy); 610 vmspace = imgp->proc->p_vmspace; 611 pmap_remove_pages(vmspace_pmap(vmspace), stack_addr, USRSTACK); 612 map = &vmspace->vm_map; 613 } else if (vmspace->vm_refcnt == 1 && vmspace->vm_exitingcnt == 0) { 614 shmexit(vmspace); 615 if (vmspace->vm_upcalls) 616 upc_release(vmspace, imgp->proc); 617 pmap_remove_pages(vmspace_pmap(vmspace), 0, VM_MAXUSER_ADDRESS); 618 vm_map_remove(map, 0, VM_MAXUSER_ADDRESS); 619 } else { 620 vmspace_exec(imgp->proc, NULL); 621 vmspace = imgp->proc->p_vmspace; 622 map = &vmspace->vm_map; 623 } 624 625 /* Allocate a new stack */ 626 error = vm_map_stack(&vmspace->vm_map, stack_addr, (vm_size_t)maxssiz, 627 VM_PROT_ALL, VM_PROT_ALL, 0); 628 if (error) 629 return (error); 630 631 /* vm_ssize and vm_maxsaddr are somewhat antiquated concepts in the 632 * VM_STACK case, but they are still used to monitor the size of the 633 * process stack so we can check the stack rlimit. 634 */ 635 vmspace->vm_ssize = sgrowsiz >> PAGE_SHIFT; 636 vmspace->vm_maxsaddr = (char *)USRSTACK - maxssiz; 637 638 return(0); 639 } 640 641 /* 642 * Copy out argument and environment strings from the old process 643 * address space into the temporary string buffer. 644 */ 645 int 646 exec_copyin_args(struct image_args *args, char *fname, 647 enum exec_path_segflg segflg, char **argv, char **envv) 648 { 649 char *argp, *envp; 650 int error = 0; 651 size_t length; 652 653 bzero(args, sizeof(*args)); 654 args->buf = (char *) kmem_alloc_wait(exec_map, PATH_MAX + ARG_MAX); 655 if (args->buf == NULL) 656 return (ENOMEM); 657 args->begin_argv = args->buf; 658 args->endp = args->begin_argv; 659 args->space = ARG_MAX; 660 661 args->fname = args->buf + ARG_MAX; 662 663 /* 664 * Copy the file name. 665 */ 666 if (segflg == PATH_SYSSPACE) { 667 error = copystr(fname, args->fname, PATH_MAX, &length); 668 } else if (segflg == PATH_USERSPACE) { 669 error = copyinstr(fname, args->fname, PATH_MAX, &length); 670 } 671 672 /* 673 * extract argument strings 674 */ 675 676 if (argv && error == 0) { 677 /* 678 * The argv0 argument for execv() is allowed to be NULL, 679 * in which case we use our filename as argv[0]. 680 * This guarantees that 681 * the interpreter knows what file to open in the case 682 * that we exec an interpreted file. 683 */ 684 argp = (caddr_t) (intptr_t) fuword(argv); 685 if (argp == NULL) { 686 length = strlen(args->fname) + 1; 687 KKASSERT(length <= args->space); 688 bcopy(args->fname, args->endp, length); 689 args->space -= length; 690 args->endp += length; 691 args->argc++; 692 argv++; 693 } 694 while ((argp = (caddr_t) (intptr_t) fuword(argv++))) { 695 if (argp == (caddr_t) -1) { 696 error = EFAULT; 697 goto cleanup; 698 } 699 error = copyinstr(argp, args->endp, 700 args->space, &length); 701 if (error == ENAMETOOLONG) 702 error = E2BIG; 703 if (error) 704 goto cleanup; 705 args->space -= length; 706 args->endp += length; 707 args->argc++; 708 } 709 } 710 711 args->begin_envv = args->endp; 712 713 /* 714 * extract environment strings 715 */ 716 if (envv && error == 0) { 717 while ((envp = (caddr_t) (intptr_t) fuword(envv++))) { 718 if (envp == (caddr_t) -1) { 719 error = EFAULT; 720 goto cleanup; 721 } 722 error = copyinstr(envp, args->endp, args->space, 723 &length); 724 if (error == ENAMETOOLONG) 725 error = E2BIG; 726 if (error) 727 goto cleanup; 728 args->space -= length; 729 args->endp += length; 730 args->envc++; 731 } 732 } 733 734 cleanup: 735 return (error); 736 } 737 738 void 739 exec_free_args(struct image_args *args) 740 { 741 if (args->buf) { 742 kmem_free_wakeup(exec_map, 743 (vm_offset_t)args->buf, PATH_MAX + ARG_MAX); 744 args->buf = NULL; 745 } 746 } 747 748 /* 749 * Copy strings out to the new process address space, constructing 750 * new arg and env vector tables. Return a pointer to the base 751 * so that it can be used as the initial stack pointer. 752 */ 753 register_t * 754 exec_copyout_strings(struct image_params *imgp) 755 { 756 int argc, envc; 757 char **vectp; 758 char *stringp, *destp; 759 register_t *stack_base; 760 struct ps_strings *arginfo; 761 int szsigcode; 762 763 /* 764 * Calculate string base and vector table pointers. 765 * Also deal with signal trampoline code for this exec type. 766 */ 767 arginfo = (struct ps_strings *)PS_STRINGS; 768 szsigcode = *(imgp->proc->p_sysent->sv_szsigcode); 769 destp = (caddr_t)arginfo - szsigcode - SPARE_USRSPACE - 770 roundup((ARG_MAX - imgp->args->space), sizeof(char *)); 771 772 /* 773 * install sigcode 774 */ 775 if (szsigcode) 776 copyout(imgp->proc->p_sysent->sv_sigcode, 777 ((caddr_t)arginfo - szsigcode), szsigcode); 778 779 /* 780 * If we have a valid auxargs ptr, prepare some room 781 * on the stack. 782 * 783 * The '+ 2' is for the null pointers at the end of each of the 784 * arg and env vector sets, and 'AT_COUNT*2' is room for the 785 * ELF Auxargs data. 786 */ 787 if (imgp->auxargs) { 788 vectp = (char **)(destp - (imgp->args->argc + 789 imgp->args->envc + 2 + AT_COUNT * 2) * sizeof(char*)); 790 } else { 791 vectp = (char **)(destp - (imgp->args->argc + 792 imgp->args->envc + 2) * sizeof(char*)); 793 } 794 795 /* 796 * NOTE: don't bother aligning the stack here for GCC 2.x, it will 797 * be done in crt1.o. Note that GCC 3.x aligns the stack in main. 798 */ 799 800 /* 801 * vectp also becomes our initial stack base 802 */ 803 stack_base = (register_t *)vectp; 804 805 stringp = imgp->args->begin_argv; 806 argc = imgp->args->argc; 807 envc = imgp->args->envc; 808 809 /* 810 * Copy out strings - arguments and environment. 811 */ 812 copyout(stringp, destp, ARG_MAX - imgp->args->space); 813 814 /* 815 * Fill in "ps_strings" struct for ps, w, etc. 816 */ 817 suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp); 818 suword(&arginfo->ps_nargvstr, argc); 819 820 /* 821 * Fill in argument portion of vector table. 822 */ 823 for (; argc > 0; --argc) { 824 suword(vectp++, (long)(intptr_t)destp); 825 while (*stringp++ != 0) 826 destp++; 827 destp++; 828 } 829 830 /* a null vector table pointer separates the argp's from the envp's */ 831 suword(vectp++, 0); 832 833 suword(&arginfo->ps_envstr, (long)(intptr_t)vectp); 834 suword(&arginfo->ps_nenvstr, envc); 835 836 /* 837 * Fill in environment portion of vector table. 838 */ 839 for (; envc > 0; --envc) { 840 suword(vectp++, (long)(intptr_t)destp); 841 while (*stringp++ != 0) 842 destp++; 843 destp++; 844 } 845 846 /* end of vector table is a null pointer */ 847 suword(vectp, 0); 848 849 return (stack_base); 850 } 851 852 /* 853 * Check permissions of file to execute. 854 * Return 0 for success or error code on failure. 855 */ 856 int 857 exec_check_permissions(imgp) 858 struct image_params *imgp; 859 { 860 struct proc *p = imgp->proc; 861 struct vnode *vp = imgp->vp; 862 struct vattr *attr = imgp->attr; 863 struct thread *td = p->p_thread; 864 int error; 865 866 /* Get file attributes */ 867 error = VOP_GETATTR(vp, attr, td); 868 if (error) 869 return (error); 870 871 /* 872 * 1) Check if file execution is disabled for the filesystem that this 873 * file resides on. 874 * 2) Insure that at least one execute bit is on - otherwise root 875 * will always succeed, and we don't want to happen unless the 876 * file really is executable. 877 * 3) Insure that the file is a regular file. 878 */ 879 if ((vp->v_mount->mnt_flag & MNT_NOEXEC) || 880 ((attr->va_mode & 0111) == 0) || 881 (attr->va_type != VREG)) { 882 return (EACCES); 883 } 884 885 /* 886 * Zero length files can't be exec'd 887 */ 888 if (attr->va_size == 0) 889 return (ENOEXEC); 890 891 /* 892 * Check for execute permission to file based on current credentials. 893 */ 894 error = VOP_ACCESS(vp, VEXEC, p->p_ucred, td); 895 if (error) 896 return (error); 897 898 /* 899 * Check number of open-for-writes on the file and deny execution 900 * if there are any. 901 */ 902 if (vp->v_writecount) 903 return (ETXTBSY); 904 905 /* 906 * Call filesystem specific open routine (which does nothing in the 907 * general case). 908 */ 909 error = VOP_OPEN(vp, FREAD, p->p_ucred, td); 910 if (error) 911 return (error); 912 913 return (0); 914 } 915 916 /* 917 * Exec handler registration 918 */ 919 int 920 exec_register(execsw_arg) 921 const struct execsw *execsw_arg; 922 { 923 const struct execsw **es, **xs, **newexecsw; 924 int count = 2; /* New slot and trailing NULL */ 925 926 if (execsw) 927 for (es = execsw; *es; es++) 928 count++; 929 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 930 if (newexecsw == NULL) 931 return ENOMEM; 932 xs = newexecsw; 933 if (execsw) 934 for (es = execsw; *es; es++) 935 *xs++ = *es; 936 *xs++ = execsw_arg; 937 *xs = NULL; 938 if (execsw) 939 free(execsw, M_TEMP); 940 execsw = newexecsw; 941 return 0; 942 } 943 944 int 945 exec_unregister(execsw_arg) 946 const struct execsw *execsw_arg; 947 { 948 const struct execsw **es, **xs, **newexecsw; 949 int count = 1; 950 951 if (execsw == NULL) 952 panic("unregister with no handlers left?"); 953 954 for (es = execsw; *es; es++) { 955 if (*es == execsw_arg) 956 break; 957 } 958 if (*es == NULL) 959 return ENOENT; 960 for (es = execsw; *es; es++) 961 if (*es != execsw_arg) 962 count++; 963 newexecsw = malloc(count * sizeof(*es), M_TEMP, M_WAITOK); 964 if (newexecsw == NULL) 965 return ENOMEM; 966 xs = newexecsw; 967 for (es = execsw; *es; es++) 968 if (*es != execsw_arg) 969 *xs++ = *es; 970 *xs = NULL; 971 if (execsw) 972 free(execsw, M_TEMP); 973 execsw = newexecsw; 974 return 0; 975 } 976