1 /* $OpenBSD: kern_exec.c,v 1.182 2016/06/11 21:00:11 kettenis Exp $ */ 2 /* $NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $ */ 3 4 /*- 5 * Copyright (C) 1993, 1994 Christopher G. Demetriou 6 * Copyright (C) 1992 Wolfgang Solfrank. 7 * Copyright (C) 1992 TooLs GmbH. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by TooLs GmbH. 21 * 4. The name of TooLs GmbH may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/filedesc.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/mount.h> 42 #include <sys/malloc.h> 43 #include <sys/pool.h> 44 #include <sys/namei.h> 45 #include <sys/vnode.h> 46 #include <sys/file.h> 47 #include <sys/acct.h> 48 #include <sys/exec.h> 49 #include <sys/ktrace.h> 50 #include <sys/resourcevar.h> 51 #include <sys/wait.h> 52 #include <sys/mman.h> 53 #include <sys/signalvar.h> 54 #include <sys/stat.h> 55 #include <sys/conf.h> 56 #include <sys/pledge.h> 57 #ifdef SYSVSHM 58 #include <sys/shm.h> 59 #endif 60 61 #include <sys/syscallargs.h> 62 63 #include <uvm/uvm_extern.h> 64 65 #ifdef __HAVE_MD_TCB 66 # include <machine/tcb.h> 67 #endif 68 69 const struct kmem_va_mode kv_exec = { 70 .kv_wait = 1, 71 .kv_map = &exec_map 72 }; 73 74 /* 75 * Map the shared signal code. 76 */ 77 int exec_sigcode_map(struct process *, struct emul *); 78 79 /* 80 * If non-zero, stackgap_random specifies the upper limit of the random gap size 81 * added to the fixed stack position. Must be n^2. 82 */ 83 int stackgap_random = STACKGAP_RANDOM; 84 85 /* 86 * check exec: 87 * given an "executable" described in the exec package's namei info, 88 * see what we can do with it. 89 * 90 * ON ENTRY: 91 * exec package with appropriate namei info 92 * proc pointer of exec'ing proc 93 * NO SELF-LOCKED VNODES 94 * 95 * ON EXIT: 96 * error: nothing held, etc. exec header still allocated. 97 * ok: filled exec package, one locked vnode. 98 * 99 * EXEC SWITCH ENTRY: 100 * Locked vnode to check, exec package, proc. 101 * 102 * EXEC SWITCH EXIT: 103 * ok: return 0, filled exec package, one locked vnode. 104 * error: destructive: 105 * everything deallocated except exec header. 106 * non-destructive: 107 * error code, locked vnode, exec header unmodified 108 */ 109 int 110 check_exec(struct proc *p, struct exec_package *epp) 111 { 112 int error, i; 113 struct vnode *vp; 114 struct nameidata *ndp; 115 size_t resid; 116 117 ndp = epp->ep_ndp; 118 ndp->ni_cnd.cn_nameiop = LOOKUP; 119 ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF | SAVENAME; 120 /* first get the vnode */ 121 if ((error = namei(ndp)) != 0) 122 return (error); 123 epp->ep_vp = vp = ndp->ni_vp; 124 125 /* check for regular file */ 126 if (vp->v_type == VDIR) { 127 error = EISDIR; 128 goto bad1; 129 } 130 if (vp->v_type != VREG) { 131 error = EACCES; 132 goto bad1; 133 } 134 135 /* get attributes */ 136 if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0) 137 goto bad1; 138 139 /* Check mount point */ 140 if (vp->v_mount->mnt_flag & MNT_NOEXEC) { 141 error = EACCES; 142 goto bad1; 143 } 144 145 if ((vp->v_mount->mnt_flag & MNT_NOSUID)) 146 epp->ep_vap->va_mode &= ~(VSUID | VSGID); 147 148 /* check access. for root we have to see if any exec bit on */ 149 if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0) 150 goto bad1; 151 if ((epp->ep_vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) { 152 error = EACCES; 153 goto bad1; 154 } 155 156 /* try to open it */ 157 if ((error = VOP_OPEN(vp, FREAD, p->p_ucred, p)) != 0) 158 goto bad1; 159 160 /* unlock vp, we need it unlocked from here */ 161 VOP_UNLOCK(vp, p); 162 163 /* now we have the file, get the exec header */ 164 error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, 165 UIO_SYSSPACE, 0, p->p_ucred, &resid, p); 166 if (error) 167 goto bad2; 168 epp->ep_hdrvalid = epp->ep_hdrlen - resid; 169 170 /* 171 * set up the vmcmds for creation of the process 172 * address space 173 */ 174 error = ENOEXEC; 175 for (i = 0; i < nexecs && error != 0; i++) { 176 int newerror; 177 178 if (execsw[i].es_check == NULL) 179 continue; 180 newerror = (*execsw[i].es_check)(p, epp); 181 if (!newerror && !(epp->ep_emul->e_flags & EMUL_ENABLED)) 182 newerror = EPERM; 183 /* make sure the first "interesting" error code is saved. */ 184 if (!newerror || error == ENOEXEC) 185 error = newerror; 186 if (epp->ep_flags & EXEC_DESTR && error != 0) 187 return (error); 188 } 189 if (!error) { 190 /* check that entry point is sane */ 191 if (epp->ep_entry > VM_MAXUSER_ADDRESS) { 192 error = ENOEXEC; 193 } 194 195 /* check limits */ 196 if ((epp->ep_tsize > MAXTSIZ) || 197 (epp->ep_dsize > p->p_rlimit[RLIMIT_DATA].rlim_cur)) 198 error = ENOMEM; 199 200 if (!error) 201 return (0); 202 } 203 204 /* 205 * free any vmspace-creation commands, 206 * and release their references 207 */ 208 kill_vmcmds(&epp->ep_vmcmds); 209 210 bad2: 211 /* 212 * close the vnode, free the pathname buf, and punt. 213 */ 214 vn_close(vp, FREAD, p->p_ucred, p); 215 pool_put(&namei_pool, ndp->ni_cnd.cn_pnbuf); 216 return (error); 217 218 bad1: 219 /* 220 * free the namei pathname buffer, and put the vnode 221 * (which we don't yet have open). 222 */ 223 pool_put(&namei_pool, ndp->ni_cnd.cn_pnbuf); 224 vput(vp); 225 return (error); 226 } 227 228 /* 229 * exec system call 230 */ 231 int 232 sys_execve(struct proc *p, void *v, register_t *retval) 233 { 234 struct sys_execve_args /* { 235 syscallarg(const char *) path; 236 syscallarg(char *const *) argp; 237 syscallarg(char *const *) envp; 238 } */ *uap = v; 239 int error; 240 struct exec_package pack; 241 struct nameidata nid; 242 struct vattr attr; 243 struct ucred *cred = p->p_ucred; 244 char *argp; 245 char * const *cpp, *dp, *sp; 246 #ifdef KTRACE 247 char *env_start; 248 #endif 249 struct process *pr = p->p_p; 250 long argc, envc; 251 size_t len, sgap; 252 #ifdef MACHINE_STACK_GROWS_UP 253 size_t slen; 254 #endif 255 char *stack; 256 struct ps_strings arginfo; 257 struct vmspace *vm = pr->ps_vmspace; 258 char **tmpfap; 259 extern struct emul emul_native; 260 struct vnode *otvp; 261 262 /* get other threads to stop */ 263 if ((error = single_thread_set(p, SINGLE_UNWIND, 1))) 264 return (error); 265 266 /* 267 * Cheap solution to complicated problems. 268 * Mark this process as "leave me alone, I'm execing". 269 */ 270 atomic_setbits_int(&pr->ps_flags, PS_INEXEC); 271 272 NDINIT(&nid, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 273 nid.ni_pledge = PLEDGE_EXEC; 274 275 /* 276 * initialize the fields of the exec package. 277 */ 278 pack.ep_name = (char *)SCARG(uap, path); 279 pack.ep_hdr = malloc(exec_maxhdrsz, M_EXEC, M_WAITOK); 280 pack.ep_hdrlen = exec_maxhdrsz; 281 pack.ep_hdrvalid = 0; 282 pack.ep_ndp = &nid; 283 pack.ep_interp = NULL; 284 pack.ep_emul_arg = NULL; 285 VMCMDSET_INIT(&pack.ep_vmcmds); 286 pack.ep_vap = &attr; 287 pack.ep_emul = &emul_native; 288 pack.ep_flags = 0; 289 290 /* see if we can run it. */ 291 if ((error = check_exec(p, &pack)) != 0) { 292 goto freehdr; 293 } 294 295 /* XXX -- THE FOLLOWING SECTION NEEDS MAJOR CLEANUP */ 296 297 /* allocate an argument buffer */ 298 argp = km_alloc(NCARGS, &kv_exec, &kp_pageable, &kd_waitok); 299 #ifdef DIAGNOSTIC 300 if (argp == NULL) 301 panic("execve: argp == NULL"); 302 #endif 303 dp = argp; 304 argc = 0; 305 306 /* copy the fake args list, if there's one, freeing it as we go */ 307 if (pack.ep_flags & EXEC_HASARGL) { 308 tmpfap = pack.ep_fa; 309 while (*tmpfap != NULL) { 310 char *cp; 311 312 cp = *tmpfap; 313 while (*cp) 314 *dp++ = *cp++; 315 *dp++ = '\0'; 316 317 free(*tmpfap, M_EXEC, 0); 318 tmpfap++; argc++; 319 } 320 free(pack.ep_fa, M_EXEC, 0); 321 pack.ep_flags &= ~EXEC_HASARGL; 322 } 323 324 /* Now get argv & environment */ 325 if (!(cpp = SCARG(uap, argp))) { 326 error = EFAULT; 327 goto bad; 328 } 329 330 if (pack.ep_flags & EXEC_SKIPARG) 331 cpp++; 332 333 while (1) { 334 len = argp + ARG_MAX - dp; 335 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 336 goto bad; 337 if (!sp) 338 break; 339 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 340 if (error == ENAMETOOLONG) 341 error = E2BIG; 342 goto bad; 343 } 344 dp += len; 345 cpp++; 346 argc++; 347 } 348 349 /* must have at least one argument */ 350 if (argc == 0) { 351 error = EINVAL; 352 goto bad; 353 } 354 355 #ifdef KTRACE 356 if (KTRPOINT(p, KTR_EXECARGS)) 357 ktrexec(p, KTR_EXECARGS, argp, dp - argp); 358 #endif 359 360 envc = 0; 361 /* environment does not need to be there */ 362 if ((cpp = SCARG(uap, envp)) != NULL ) { 363 #ifdef KTRACE 364 env_start = dp; 365 #endif 366 while (1) { 367 len = argp + ARG_MAX - dp; 368 if ((error = copyin(cpp, &sp, sizeof(sp))) != 0) 369 goto bad; 370 if (!sp) 371 break; 372 if ((error = copyinstr(sp, dp, len, &len)) != 0) { 373 if (error == ENAMETOOLONG) 374 error = E2BIG; 375 goto bad; 376 } 377 dp += len; 378 cpp++; 379 envc++; 380 } 381 382 #ifdef KTRACE 383 if (KTRPOINT(p, KTR_EXECENV)) 384 ktrexec(p, KTR_EXECENV, env_start, dp - env_start); 385 #endif 386 } 387 388 dp = (char *)(((long)dp + _STACKALIGNBYTES) & ~_STACKALIGNBYTES); 389 390 sgap = STACKGAPLEN; 391 392 /* 393 * If we have enabled random stackgap, the stack itself has already 394 * been moved from a random location, but is still aligned to a page 395 * boundary. Provide the lower bits of random placement now. 396 */ 397 if (stackgap_random != 0) { 398 sgap += arc4random() & PAGE_MASK; 399 sgap = (sgap + _STACKALIGNBYTES) & ~_STACKALIGNBYTES; 400 } 401 402 /* Now check if args & environ fit into new stack */ 403 len = ((argc + envc + 2 + pack.ep_emul->e_arglen) * sizeof(char *) + 404 sizeof(long) + dp + sgap + sizeof(struct ps_strings)) - argp; 405 406 len = (len + _STACKALIGNBYTES) &~ _STACKALIGNBYTES; 407 408 if (len > pack.ep_ssize) { /* in effect, compare to initial limit */ 409 error = ENOMEM; 410 goto bad; 411 } 412 413 /* adjust "active stack depth" for process VSZ */ 414 pack.ep_ssize = len; /* maybe should go elsewhere, but... */ 415 416 /* 417 * we're committed: any further errors will kill the process, so 418 * kill the other threads now. 419 */ 420 single_thread_set(p, SINGLE_EXIT, 0); 421 422 /* 423 * Prepare vmspace for remapping. Note that uvmspace_exec can replace 424 * pr_vmspace! 425 */ 426 uvmspace_exec(p, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); 427 428 vm = pr->ps_vmspace; 429 /* Now map address space */ 430 vm->vm_taddr = (char *)trunc_page(pack.ep_taddr); 431 vm->vm_tsize = atop(round_page(pack.ep_taddr + pack.ep_tsize) - 432 trunc_page(pack.ep_taddr)); 433 vm->vm_daddr = (char *)trunc_page(pack.ep_daddr); 434 vm->vm_dsize = atop(round_page(pack.ep_daddr + pack.ep_dsize) - 435 trunc_page(pack.ep_daddr)); 436 vm->vm_dused = 0; 437 vm->vm_ssize = atop(round_page(pack.ep_ssize)); 438 vm->vm_maxsaddr = (char *)pack.ep_maxsaddr; 439 vm->vm_minsaddr = (char *)pack.ep_minsaddr; 440 441 /* create the new process's VM space by running the vmcmds */ 442 #ifdef DIAGNOSTIC 443 if (pack.ep_vmcmds.evs_used == 0) 444 panic("execve: no vmcmds"); 445 #endif 446 error = exec_process_vmcmds(p, &pack); 447 448 /* if an error happened, deallocate and punt */ 449 if (error) 450 goto exec_abort; 451 452 /* old "stackgap" is gone now */ 453 pr->ps_stackgap = 0; 454 455 #ifdef MACHINE_STACK_GROWS_UP 456 pr->ps_strings = (vaddr_t)vm->vm_maxsaddr + sgap; 457 if (uvm_map_protect(&vm->vm_map, (vaddr_t)vm->vm_maxsaddr, 458 trunc_page(pr->ps_strings), PROT_NONE, TRUE)) 459 goto exec_abort; 460 #else 461 pr->ps_strings = (vaddr_t)vm->vm_minsaddr - sizeof(arginfo) - sgap; 462 if (uvm_map_protect(&vm->vm_map, 463 round_page(pr->ps_strings + sizeof(arginfo)), 464 (vaddr_t)vm->vm_minsaddr, PROT_NONE, TRUE)) 465 goto exec_abort; 466 #endif 467 468 /* remember information about the process */ 469 arginfo.ps_nargvstr = argc; 470 arginfo.ps_nenvstr = envc; 471 472 #ifdef MACHINE_STACK_GROWS_UP 473 stack = (char *)vm->vm_maxsaddr + sizeof(arginfo) + sgap; 474 slen = len - sizeof(arginfo) - sgap; 475 #else 476 stack = (char *)(vm->vm_minsaddr - len); 477 #endif 478 /* Now copy argc, args & environ to new stack */ 479 if (!(*pack.ep_emul->e_copyargs)(&pack, &arginfo, stack, argp)) 480 goto exec_abort; 481 482 /* copy out the process's ps_strings structure */ 483 if (copyout(&arginfo, (char *)pr->ps_strings, sizeof(arginfo))) 484 goto exec_abort; 485 486 stopprofclock(pr); /* stop profiling */ 487 fdcloseexec(p); /* handle close on exec */ 488 execsigs(p); /* reset caught signals */ 489 TCB_SET(p, NULL); /* reset the TCB address */ 490 pr->ps_kbind_addr = 0; /* reset the kbind bits */ 491 pr->ps_kbind_cookie = 0; 492 arc4random_buf(&pr->ps_sigcookie, sizeof pr->ps_sigcookie); 493 494 /* set command name & other accounting info */ 495 memset(p->p_comm, 0, sizeof(p->p_comm)); 496 len = min(nid.ni_cnd.cn_namelen, MAXCOMLEN); 497 memcpy(p->p_comm, nid.ni_cnd.cn_nameptr, len); 498 pr->ps_acflag &= ~AFORK; 499 500 /* record proc's vnode, for use by sysctl */ 501 otvp = pr->ps_textvp; 502 vref(pack.ep_vp); 503 pr->ps_textvp = pack.ep_vp; 504 if (otvp) 505 vrele(otvp); 506 507 atomic_setbits_int(&pr->ps_flags, PS_EXEC); 508 if (pr->ps_flags & PS_PPWAIT) { 509 atomic_clearbits_int(&pr->ps_flags, PS_PPWAIT); 510 atomic_clearbits_int(&pr->ps_pptr->ps_flags, PS_ISPWAIT); 511 wakeup(pr->ps_pptr); 512 } 513 514 /* 515 * If process does execve() while it has a mismatched real, 516 * effective, or saved uid/gid, we set PS_SUGIDEXEC. 517 */ 518 if (cred->cr_uid != cred->cr_ruid || 519 cred->cr_uid != cred->cr_svuid || 520 cred->cr_gid != cred->cr_rgid || 521 cred->cr_gid != cred->cr_svgid) 522 atomic_setbits_int(&pr->ps_flags, PS_SUGIDEXEC); 523 else 524 atomic_clearbits_int(&pr->ps_flags, PS_SUGIDEXEC); 525 526 atomic_clearbits_int(&pr->ps_flags, PS_PLEDGE); 527 pledge_dropwpaths(pr); 528 529 /* 530 * deal with set[ug]id. 531 * MNT_NOEXEC has already been used to disable s[ug]id. 532 */ 533 if ((attr.va_mode & (VSUID | VSGID)) && proc_cansugid(p)) { 534 int i; 535 536 atomic_setbits_int(&pr->ps_flags, PS_SUGID|PS_SUGIDEXEC); 537 538 #ifdef KTRACE 539 /* 540 * If process is being ktraced, turn off - unless 541 * root set it. 542 */ 543 if (pr->ps_tracevp && !(pr->ps_traceflag & KTRFAC_ROOT)) 544 ktrcleartrace(pr); 545 #endif 546 p->p_ucred = cred = crcopy(cred); 547 if (attr.va_mode & VSUID) 548 cred->cr_uid = attr.va_uid; 549 if (attr.va_mode & VSGID) 550 cred->cr_gid = attr.va_gid; 551 552 /* 553 * For set[ug]id processes, a few caveats apply to 554 * stdin, stdout, and stderr. 555 */ 556 error = 0; 557 fdplock(p->p_fd); 558 for (i = 0; i < 3; i++) { 559 struct file *fp = NULL; 560 561 /* 562 * NOTE - This will never return NULL because of 563 * immature fds. The file descriptor table is not 564 * shared because we're suid. 565 */ 566 fp = fd_getfile(p->p_fd, i); 567 568 /* 569 * Ensure that stdin, stdout, and stderr are already 570 * allocated. We do not want userland to accidentally 571 * allocate descriptors in this range which has implied 572 * meaning to libc. 573 */ 574 if (fp == NULL) { 575 short flags = FREAD | (i == 0 ? 0 : FWRITE); 576 struct vnode *vp; 577 int indx; 578 579 if ((error = falloc(p, &fp, &indx)) != 0) 580 break; 581 #ifdef DIAGNOSTIC 582 if (indx != i) 583 panic("sys_execve: falloc indx != i"); 584 #endif 585 if ((error = cdevvp(getnulldev(), &vp)) != 0) { 586 fdremove(p->p_fd, indx); 587 closef(fp, p); 588 break; 589 } 590 if ((error = VOP_OPEN(vp, flags, cred, p)) != 0) { 591 fdremove(p->p_fd, indx); 592 closef(fp, p); 593 vrele(vp); 594 break; 595 } 596 if (flags & FWRITE) 597 vp->v_writecount++; 598 fp->f_flag = flags; 599 fp->f_type = DTYPE_VNODE; 600 fp->f_ops = &vnops; 601 fp->f_data = (caddr_t)vp; 602 FILE_SET_MATURE(fp, p); 603 } 604 } 605 fdpunlock(p->p_fd); 606 if (error) 607 goto exec_abort; 608 } else 609 atomic_clearbits_int(&pr->ps_flags, PS_SUGID); 610 611 /* 612 * Reset the saved ugids and update the process's copy of the 613 * creds if the creds have been changed 614 */ 615 if (cred->cr_uid != cred->cr_svuid || 616 cred->cr_gid != cred->cr_svgid) { 617 /* make sure we have unshared ucreds */ 618 p->p_ucred = cred = crcopy(cred); 619 cred->cr_svuid = cred->cr_uid; 620 cred->cr_svgid = cred->cr_gid; 621 } 622 623 if (pr->ps_ucred != cred) { 624 struct ucred *ocred; 625 626 ocred = pr->ps_ucred; 627 crhold(cred); 628 pr->ps_ucred = cred; 629 crfree(ocred); 630 } 631 632 if (pr->ps_flags & PS_SUGIDEXEC) { 633 int i, s = splclock(); 634 635 timeout_del(&pr->ps_realit_to); 636 for (i = 0; i < nitems(pr->ps_timer); i++) { 637 timerclear(&pr->ps_timer[i].it_interval); 638 timerclear(&pr->ps_timer[i].it_value); 639 } 640 splx(s); 641 } 642 643 /* reset CPU time usage for the thread, but not the process */ 644 timespecclear(&p->p_tu.tu_runtime); 645 p->p_tu.tu_uticks = p->p_tu.tu_sticks = p->p_tu.tu_iticks = 0; 646 647 km_free(argp, NCARGS, &kv_exec, &kp_pageable); 648 649 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf); 650 vn_close(pack.ep_vp, FREAD, cred, p); 651 652 /* 653 * notify others that we exec'd 654 */ 655 KNOTE(&pr->ps_klist, NOTE_EXEC); 656 657 /* setup new registers and do misc. setup. */ 658 if (pack.ep_emul->e_fixup != NULL) { 659 if ((*pack.ep_emul->e_fixup)(p, &pack) != 0) 660 goto free_pack_abort; 661 } 662 #ifdef MACHINE_STACK_GROWS_UP 663 (*pack.ep_emul->e_setregs)(p, &pack, (u_long)stack + slen, retval); 664 #else 665 (*pack.ep_emul->e_setregs)(p, &pack, (u_long)stack, retval); 666 #endif 667 668 /* map the process's signal trampoline code */ 669 if (exec_sigcode_map(pr, pack.ep_emul)) 670 goto free_pack_abort; 671 672 #ifdef __HAVE_EXEC_MD_MAP 673 /* perform md specific mappings that process might need */ 674 if (exec_md_map(p, &pack)) 675 goto free_pack_abort; 676 #endif 677 678 if (pr->ps_flags & PS_TRACED) 679 psignal(p, SIGTRAP); 680 681 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen); 682 683 /* 684 * Call emulation specific exec hook. This can setup per-process 685 * p->p_emuldata or do any other per-process stuff an emulation needs. 686 * 687 * If we are executing process of different emulation than the 688 * original forked process, call e_proc_exit() of the old emulation 689 * first, then e_proc_exec() of new emulation. If the emulation is 690 * same, the exec hook code should deallocate any old emulation 691 * resources held previously by this process. 692 */ 693 if (pr->ps_emul && pr->ps_emul->e_proc_exit && 694 pr->ps_emul != pack.ep_emul) 695 (*pr->ps_emul->e_proc_exit)(p); 696 697 p->p_descfd = 255; 698 if ((pack.ep_flags & EXEC_HASFD) && pack.ep_fd < 255) 699 p->p_descfd = pack.ep_fd; 700 701 if (pack.ep_flags & EXEC_WXNEEDED) 702 p->p_p->ps_flags |= PS_WXNEEDED; 703 704 /* 705 * Call exec hook. Emulation code may NOT store reference to anything 706 * from &pack. 707 */ 708 if (pack.ep_emul->e_proc_exec) 709 (*pack.ep_emul->e_proc_exec)(p, &pack); 710 711 /* update ps_emul, the old value is no longer needed */ 712 pr->ps_emul = pack.ep_emul; 713 714 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC); 715 single_thread_clear(p, P_SUSPSIG); 716 717 return (0); 718 719 bad: 720 /* free the vmspace-creation commands, and release their references */ 721 kill_vmcmds(&pack.ep_vmcmds); 722 /* kill any opened file descriptor, if necessary */ 723 if (pack.ep_flags & EXEC_HASFD) { 724 pack.ep_flags &= ~EXEC_HASFD; 725 fdplock(p->p_fd); 726 (void) fdrelease(p, pack.ep_fd); 727 fdpunlock(p->p_fd); 728 } 729 if (pack.ep_interp != NULL) 730 pool_put(&namei_pool, pack.ep_interp); 731 if (pack.ep_emul_arg != NULL) 732 free(pack.ep_emul_arg, M_TEMP, pack.ep_emul_argsize); 733 /* close and put the exec'd file */ 734 vn_close(pack.ep_vp, FREAD, cred, p); 735 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf); 736 km_free(argp, NCARGS, &kv_exec, &kp_pageable); 737 738 freehdr: 739 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen); 740 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC); 741 single_thread_clear(p, P_SUSPSIG); 742 743 return (error); 744 745 exec_abort: 746 /* 747 * the old process doesn't exist anymore. exit gracefully. 748 * get rid of the (new) address space we have created, if any, get rid 749 * of our namei data and vnode, and exit noting failure 750 */ 751 uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, 752 VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); 753 if (pack.ep_interp != NULL) 754 pool_put(&namei_pool, pack.ep_interp); 755 if (pack.ep_emul_arg != NULL) 756 free(pack.ep_emul_arg, M_TEMP, pack.ep_emul_argsize); 757 pool_put(&namei_pool, nid.ni_cnd.cn_pnbuf); 758 vn_close(pack.ep_vp, FREAD, cred, p); 759 km_free(argp, NCARGS, &kv_exec, &kp_pageable); 760 761 free_pack_abort: 762 free(pack.ep_hdr, M_EXEC, pack.ep_hdrlen); 763 exit1(p, W_EXITCODE(0, SIGABRT), EXIT_NORMAL); 764 765 /* NOTREACHED */ 766 atomic_clearbits_int(&pr->ps_flags, PS_INEXEC); 767 768 return (0); 769 } 770 771 772 void * 773 copyargs(struct exec_package *pack, struct ps_strings *arginfo, void *stack, 774 void *argp) 775 { 776 char **cpp = stack; 777 char *dp, *sp; 778 size_t len; 779 void *nullp = NULL; 780 long argc = arginfo->ps_nargvstr; 781 int envc = arginfo->ps_nenvstr; 782 783 if (copyout(&argc, cpp++, sizeof(argc))) 784 return (NULL); 785 786 dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen); 787 sp = argp; 788 789 /* XXX don't copy them out, remap them! */ 790 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 791 792 for (; --argc >= 0; sp += len, dp += len) 793 if (copyout(&dp, cpp++, sizeof(dp)) || 794 copyoutstr(sp, dp, ARG_MAX, &len)) 795 return (NULL); 796 797 if (copyout(&nullp, cpp++, sizeof(nullp))) 798 return (NULL); 799 800 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 801 802 for (; --envc >= 0; sp += len, dp += len) 803 if (copyout(&dp, cpp++, sizeof(dp)) || 804 copyoutstr(sp, dp, ARG_MAX, &len)) 805 return (NULL); 806 807 if (copyout(&nullp, cpp++, sizeof(nullp))) 808 return (NULL); 809 810 return (cpp); 811 } 812 813 int 814 exec_sigcode_map(struct process *pr, struct emul *e) 815 { 816 vsize_t sz; 817 818 sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; 819 820 /* 821 * If we don't have a sigobject for this emulation, create one. 822 * 823 * sigobject is an anonymous memory object (just like SYSV shared 824 * memory) that we keep a permanent reference to and that we map 825 * in all processes that need this sigcode. The creation is simple, 826 * we create an object, add a permanent reference to it, map it in 827 * kernel space, copy out the sigcode to it and unmap it. 828 * Then we map it with PROT_READ|PROT_EXEC into the process just 829 * the way sys_mmap would map it. 830 */ 831 if (e->e_sigobject == NULL) { 832 extern int sigfillsiz; 833 extern u_char sigfill[]; 834 size_t off; 835 vaddr_t va; 836 int r; 837 838 e->e_sigobject = uao_create(sz, 0); 839 uao_reference(e->e_sigobject); /* permanent reference */ 840 841 if ((r = uvm_map(kernel_map, &va, round_page(sz), e->e_sigobject, 842 0, 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE, 843 MAP_INHERIT_SHARE, MADV_RANDOM, 0)))) { 844 uao_detach(e->e_sigobject); 845 return (ENOMEM); 846 } 847 848 for (off = 0; off < round_page(sz); off += sigfillsiz) 849 memcpy((caddr_t)va + off, sigfill, sigfillsiz); 850 memcpy((caddr_t)va, e->e_sigcode, sz); 851 uvm_unmap(kernel_map, va, va + round_page(sz)); 852 } 853 854 pr->ps_sigcode = 0; /* no hint */ 855 uao_reference(e->e_sigobject); 856 if (uvm_map(&pr->ps_vmspace->vm_map, &pr->ps_sigcode, round_page(sz), 857 e->e_sigobject, 0, 0, UVM_MAPFLAG(PROT_READ | PROT_EXEC, 858 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_INHERIT_COPY, 859 MADV_RANDOM, UVM_FLAG_COPYONW))) { 860 uao_detach(e->e_sigobject); 861 return (ENOMEM); 862 } 863 864 /* Calculate PC at point of sigreturn entry */ 865 pr->ps_sigcoderet = pr->ps_sigcode + 866 (pr->ps_emul->e_esigret - pr->ps_emul->e_sigcode); 867 868 return (0); 869 } 870