xref: /netbsd-src/sys/kern/exec_elf32.c (revision 95d875fb90b1458e4f1de6950286ddcd6644bc61)
1 /*	$NetBSD: exec_elf32.c,v 1.46 1999/10/25 13:55:07 kleink Exp $	*/
2 
3 /*-
4  * Copyright (c) 1994 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Christos Zoulas.
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 the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright (c) 1996 Christopher G. Demetriou
41  * All rights reserved.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. The name of the author may not be used to endorse or promote products
52  *    derived from this software without specific prior written permission
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
55  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
56  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
57  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
58  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
59  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
60  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
61  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
62  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
63  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
64  */
65 
66 /* If not included by exec_elf64.c, ELFSIZE won't be defined. */
67 #ifndef ELFSIZE
68 #define	ELFSIZE		32
69 #endif
70 
71 #include "opt_compat_linux.h"
72 #include "opt_compat_ibcs2.h"
73 #include "opt_compat_svr4.h"
74 #include "opt_compat_freebsd.h"
75 
76 #include <sys/param.h>
77 #include <sys/systm.h>
78 #include <sys/kernel.h>
79 #include <sys/proc.h>
80 #include <sys/malloc.h>
81 #include <sys/namei.h>
82 #include <sys/vnode.h>
83 #include <sys/exec.h>
84 #include <sys/exec_elf.h>
85 #include <sys/fcntl.h>
86 #include <sys/syscall.h>
87 #include <sys/signalvar.h>
88 #include <sys/mount.h>
89 #include <sys/stat.h>
90 
91 #include <sys/mman.h>
92 #include <vm/vm.h>
93 #include <vm/vm_param.h>
94 #include <vm/vm_map.h>
95 
96 #include <machine/cpu.h>
97 #include <machine/reg.h>
98 
99 #ifdef COMPAT_LINUX
100 #include <compat/linux/common/linux_exec.h>
101 #endif
102 
103 #ifdef COMPAT_SVR4
104 #include <compat/svr4/svr4_exec.h>
105 #endif
106 
107 #ifdef COMPAT_IBCS2
108 #include <compat/ibcs2/ibcs2_exec.h>
109 #endif
110 
111 #ifdef COMPAT_FREEBSD
112 #include <compat/freebsd/freebsd_exec.h>
113 #endif
114 
115 int	ELFNAME(check_header) __P((Elf_Ehdr *, int));
116 int	ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *,
117 	    struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *));
118 void	ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *,
119 	    Elf_Phdr *, Elf_Addr *, u_long *, int *));
120 
121 static int ELFNAME2(netbsd,signature) __P((struct proc *, struct exec_package *,
122     Elf_Ehdr *));
123 static int ELFNAME2(netbsd,probe) __P((struct proc *, struct exec_package *,
124     Elf_Ehdr *, char *, Elf_Addr *));
125 
126 extern char sigcode[], esigcode[];
127 #ifdef SYSCALL_DEBUG
128 extern char *syscallnames[];
129 #endif
130 
131 struct emul ELFNAMEEND(emul_netbsd) = {
132 	"netbsd",
133 	NULL,
134 	sendsig,
135 	SYS_syscall,
136 	SYS_MAXSYSCALL,
137 	sysent,
138 #ifdef SYSCALL_DEBUG
139 	syscallnames,
140 #else
141 	NULL,
142 #endif
143 	howmany(ELF_AUX_ENTRIES * sizeof(AuxInfo), sizeof (char *)),
144 	ELFNAME(copyargs),
145 	setregs,
146 	sigcode,
147 	esigcode,
148 };
149 
150 int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *,
151     Elf_Ehdr *, char *, Elf_Addr *)) = {
152 	ELFNAME2(netbsd,probe),
153 #if defined(COMPAT_FREEBSD) && (ELFSIZE == 32)
154 	ELFNAME2(freebsd,probe),		/* XXX not 64-bit safe */
155 #endif
156 #if defined(COMPAT_LINUX)
157 	ELFNAME2(linux,probe),
158 #endif
159 #if defined(COMPAT_SVR4) && (ELFSIZE == 32)
160 	ELFNAME2(svr4,probe),			/* XXX not 64-bit safe */
161 #endif
162 #if defined(COMPAT_IBCS2) && (ELFSIZE == 32)
163 	ELFNAME2(ibcs2,probe),			/* XXX not 64-bit safe */
164 #endif
165 };
166 
167 /* round up and down to page boundaries. */
168 #define	ELF_ROUND(a, b)		(((a) + (b) - 1) & ~((b) - 1))
169 #define	ELF_TRUNC(a, b)		((a) & ~((b) - 1))
170 
171 /*
172  * Copy arguments onto the stack in the normal way, but add some
173  * extra information in case of dynamic binding.
174  */
175 void *
176 ELFNAME(copyargs)(pack, arginfo, stack, argp)
177 	struct exec_package *pack;
178 	struct ps_strings *arginfo;
179 	void *stack;
180 	void *argp;
181 {
182 	size_t len;
183 	AuxInfo ai[ELF_AUX_ENTRIES], *a;
184 	struct elf_args *ap;
185 
186 	stack = copyargs(pack, arginfo, stack, argp);
187 	if (!stack)
188 		return NULL;
189 
190 	a = ai;
191 
192 	/*
193 	 * Push extra arguments on the stack needed by dynamically
194 	 * linked binaries
195 	 */
196 	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
197 
198 		a->a_type = AT_PHDR;
199 		a->a_v = ap->arg_phaddr;
200 		a++;
201 
202 		a->a_type = AT_PHENT;
203 		a->a_v = ap->arg_phentsize;
204 		a++;
205 
206 		a->a_type = AT_PHNUM;
207 		a->a_v = ap->arg_phnum;
208 		a++;
209 
210 		a->a_type = AT_PAGESZ;
211 		a->a_v = NBPG;
212 		a++;
213 
214 		a->a_type = AT_BASE;
215 		a->a_v = ap->arg_interp;
216 		a++;
217 
218 		a->a_type = AT_FLAGS;
219 		a->a_v = 0;
220 		a++;
221 
222 		a->a_type = AT_ENTRY;
223 		a->a_v = ap->arg_entry;
224 		a++;
225 
226 		free((char *)ap, M_TEMP);
227 		pack->ep_emul_arg = NULL;
228 	}
229 
230 	a->a_type = AT_NULL;
231 	a->a_v = 0;
232 	a++;
233 
234 	len = (a - ai) * sizeof(AuxInfo);
235 	if (copyout(ai, stack, len))
236 		return NULL;
237 	stack = (caddr_t)stack + len;
238 
239 	return stack;
240 }
241 
242 /*
243  * elf_check_header():
244  *
245  * Check header for validity; return 0 of ok ENOEXEC if error
246  */
247 int
248 ELFNAME(check_header)(eh, type)
249 	Elf_Ehdr *eh;
250 	int type;
251 {
252 
253 	if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
254 	    eh->e_ident[EI_CLASS] != ELFCLASS)
255 
256 	switch (eh->e_machine) {
257 
258 	ELFDEFNNAME(MACHDEP_ID_CASES)
259 
260 	default:
261 		return ENOEXEC;
262 	}
263 
264 	if (eh->e_type != type)
265 		return ENOEXEC;
266 
267 	return 0;
268 }
269 
270 /*
271  * elf_load_psection():
272  *
273  * Load a psection at the appropriate address
274  */
275 void
276 ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot)
277 	struct exec_vmcmd_set *vcset;
278 	struct vnode *vp;
279 	Elf_Phdr *ph;
280 	Elf_Addr *addr;
281 	u_long *size;
282 	int *prot;
283 {
284 	u_long uaddr, msize, psize, rm, rf;
285 	long diff, offset;
286 
287 	/*
288 	 * If the user specified an address, then we load there.
289 	 */
290 	if (*addr != ELFDEFNNAME(NO_ADDR)) {
291 		if (ph->p_align > 1) {
292 			*addr = ELF_ROUND(*addr, ph->p_align);
293 			uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align);
294 		} else
295 			uaddr = ph->p_vaddr;
296 		diff = ph->p_vaddr - uaddr;
297 	} else {
298 		*addr = uaddr = ph->p_vaddr;
299 		if (ph->p_align > 1)
300 			*addr = ELF_TRUNC(uaddr, ph->p_align);
301 		diff = uaddr - *addr;
302 	}
303 
304 	*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
305 	*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
306 	*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
307 
308 	offset = ph->p_offset - diff;
309 	*size = ph->p_filesz + diff;
310 	msize = ph->p_memsz + diff;
311 	psize = round_page(*size);
312 
313 	if ((ph->p_flags & PF_W) != 0) {
314 		/*
315 		 * Because the pagedvn pager can't handle zero fill of the last
316 		 * data page if it's not page aligned we map the last page
317 		 * readvn.
318 		 */
319 		psize = trunc_page(*size);
320 		NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp,
321 		    offset, *prot);
322 		if(psize != *size)
323 			NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize,
324 			    *addr + psize, vp, offset + psize, *prot);
325 	} else
326 		NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp,
327 		    offset, *prot);
328 
329 	/*
330 	 * Check if we need to extend the size of the segment
331 	 */
332 	rm = round_page(*addr + msize);
333 	rf = round_page(*addr + *size);
334 
335 	if (rm != rf) {
336 		NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
337 		    0, *prot);
338 		*size = msize;
339 	}
340 }
341 
342 /*
343  * elf_read_from():
344  *
345  *	Read from vnode into buffer at offset.
346  */
347 int
348 ELFNAME(read_from)(p, vp, off, buf, size)
349 	struct vnode *vp;
350 	u_long off;
351 	struct proc *p;
352 	caddr_t buf;
353 	int size;
354 {
355 	int error;
356 	size_t resid;
357 
358 	if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE,
359 	    0, p->p_ucred, &resid, p)) != 0)
360 		return error;
361 	/*
362 	 * See if we got all of it
363 	 */
364 	if (resid != 0)
365 		return ENOEXEC;
366 	return 0;
367 }
368 
369 /*
370  * elf_load_file():
371  *
372  * Load a file (interpreter/library) pointed to by path
373  * [stolen from coff_load_shlib()]. Made slightly generic
374  * so it might be used externally.
375  */
376 int
377 ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last)
378 	struct proc *p;
379 	struct exec_package *epp;
380 	char *path;
381 	struct exec_vmcmd_set *vcset;
382 	u_long *entry;
383 	struct elf_args	*ap;
384 	Elf_Addr *last;
385 {
386 	int error, i;
387 	struct nameidata nd;
388 	struct vnode *vp;
389 	struct vattr attr;
390 	Elf_Ehdr eh;
391 	Elf_Phdr *ph = NULL;
392 	u_long phsize;
393 	char *bp = NULL;
394 	Elf_Addr addr = *last;
395 
396 	bp = path;
397 	/*
398 	 * 1. open file
399 	 * 2. read filehdr
400 	 * 3. map text, data, and bss out of it using VM_*
401 	 */
402 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
403 	if ((error = namei(&nd)) != 0)
404 		return error;
405 	vp = nd.ni_vp;
406 
407 	/*
408 	 * Similarly, if it's not marked as executable, or it's not a regular
409 	 * file, we don't allow it to be used.
410 	 */
411 	if (vp->v_type != VREG) {
412 		error = EACCES;
413 		goto badunlock;
414 	}
415 	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
416 		goto badunlock;
417 
418 	/* get attributes */
419 	if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
420 		goto badunlock;
421 
422 	/*
423 	 * Check mount point.  Though we're not trying to exec this binary,
424 	 * we will be executing code from it, so if the mount point
425 	 * disallows execution or set-id-ness, we punt or kill the set-id.
426 	 */
427 	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
428 		error = EACCES;
429 		goto badunlock;
430 	}
431 	if (vp->v_mount->mnt_flag & MNT_NOSUID)
432 		epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
433 
434 #ifdef notyet /* XXX cgd 960926 */
435 	XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
436 #endif
437 	VOP_UNLOCK(vp, 0);
438 
439 	if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh,
440 	    sizeof(eh))) != 0)
441 		goto bad;
442 
443 	if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
444 		goto bad;
445 
446 	phsize = eh.e_phnum * sizeof(Elf_Phdr);
447 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
448 
449 	if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff,
450 	    (caddr_t) ph, phsize)) != 0)
451 		goto bad;
452 
453 	/*
454 	 * Load all the necessary sections
455 	 */
456 	for (i = 0; i < eh.e_phnum; i++) {
457 		u_long size = 0;
458 		int prot = 0;
459 
460 		switch (ph[i].p_type) {
461 		case PT_LOAD:
462 			ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
463 			    &size, &prot);
464 			/* If entry is within this section it must be text */
465 			if (eh.e_entry >= ph[i].p_vaddr &&
466 			    eh.e_entry < (ph[i].p_vaddr + size)) {
467 				/* XXX */
468 				*entry = addr + eh.e_entry;
469 #ifdef mips
470 				*entry -= ph[i].p_vaddr;
471 #endif
472 				ap->arg_interp = addr;
473 			}
474 			addr += size;
475 			break;
476 
477 		case PT_DYNAMIC:
478 		case PT_PHDR:
479 		case PT_NOTE:
480 			break;
481 
482 		default:
483 			break;
484 		}
485 	}
486 
487 	free((char *)ph, M_TEMP);
488 	*last = addr;
489 	vrele(vp);
490 	return 0;
491 
492 badunlock:
493 	VOP_UNLOCK(vp, 0);
494 
495 bad:
496 	if (ph != NULL)
497 		free((char *)ph, M_TEMP);
498 #ifdef notyet /* XXX cgd 960926 */
499 	(maybe) VOP_CLOSE it
500 #endif
501 	vrele(vp);
502 	return error;
503 }
504 
505 /*
506  * exec_elf_makecmds(): Prepare an Elf binary's exec package
507  *
508  * First, set of the various offsets/lengths in the exec package.
509  *
510  * Then, mark the text image busy (so it can be demand paged) or error
511  * out if this is not possible.  Finally, set up vmcmds for the
512  * text, data, bss, and stack segments.
513  */
514 int
515 ELFNAME2(exec,makecmds)(p, epp)
516 	struct proc *p;
517 	struct exec_package *epp;
518 {
519 	Elf_Ehdr *eh = epp->ep_hdr;
520 	Elf_Phdr *ph, *pp;
521 	Elf_Addr phdr = 0, pos = 0;
522 	int error, i, n, nload;
523 	char interp[MAXPATHLEN];
524 	u_long phsize;
525 
526 	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
527 		return ENOEXEC;
528 
529 	/*
530 	 * XXX allow for executing shared objects. It seems silly
531 	 * but other ELF-based systems allow it as well.
532 	 */
533 	if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
534 	    ELFNAME(check_header)(eh, ET_DYN) != 0)
535 		return ENOEXEC;
536 
537 	/*
538 	 * check if vnode is in open for writing, because we want to
539 	 * demand-page out of it.  if it is, don't do it, for various
540 	 * reasons
541 	 */
542 	if (epp->ep_vp->v_writecount != 0) {
543 #ifdef DIAGNOSTIC
544 		if (epp->ep_vp->v_flag & VTEXT)
545 			panic("exec: a VTEXT vnode has writecount != 0\n");
546 #endif
547 		return ETXTBSY;
548 	}
549 	/*
550 	 * Allocate space to hold all the program headers, and read them
551 	 * from the file
552 	 */
553 	phsize = eh->e_phnum * sizeof(Elf_Phdr);
554 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
555 
556 	if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff,
557 	    (caddr_t) ph, phsize)) != 0)
558 		goto bad;
559 
560 	epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
561 	epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
562 
563 	interp[0] = '\0';
564 
565 	for (i = 0; i < eh->e_phnum; i++) {
566 		pp = &ph[i];
567 		if (pp->p_type == PT_INTERP) {
568 			if (pp->p_filesz >= sizeof(interp))
569 				goto bad;
570 			if ((error = ELFNAME(read_from)(p, epp->ep_vp,
571 			    pp->p_offset, (caddr_t) interp,
572 			    pp->p_filesz)) != 0)
573 				goto bad;
574 			break;
575 		}
576 	}
577 
578 	/*
579 	 * Setup things for native emulation.
580 	 */
581 	epp->ep_emul = &ELFNAMEEND(emul_netbsd);
582 	pos = ELFDEFNNAME(NO_ADDR);
583 
584 	/*
585 	 * On the same architecture, we may be emulating different systems.
586 	 * See which one will accept this executable. This currently only
587 	 * applies to SVR4, and IBCS2 on the i386 and Linux on the i386
588 	 * and the Alpha.
589 	 *
590 	 * Probe functions would normally see if the interpreter (if any)
591 	 * exists. Emulation packages may possibly replace the interpreter in
592 	 * interp[] with a changed path (/emul/xxx/<path>), and also
593 	 * set the ep_emul field in the exec package structure.
594 	 */
595 	n = sizeof(ELFNAME(probe_funcs)) / sizeof(ELFNAME(probe_funcs)[0]);
596 	if (n != 0) {
597 		error = ENOEXEC;
598 		for (i = 0; i < n && error; i++)
599 			error = ELFNAME(probe_funcs)[i](p, epp, eh,
600 			    interp, &pos);
601 #ifdef notyet
602 		/*
603 		 * We should really use a signature in our native binaries
604 		 * and have our own probe function for matching binaries,
605 		 * before trying the emulations. For now, if the emulation
606 		 * probes failed we default to native.
607 		 */
608 		if (error)
609 			goto bad;
610 #endif
611 	}
612 
613 	/*
614 	 * Load all the necessary sections
615 	 */
616 	for (i = nload = 0; i < eh->e_phnum; i++) {
617 		Elf_Addr  addr = ELFDEFNNAME(NO_ADDR);
618 		u_long size = 0;
619 		int prot = 0;
620 
621 		pp = &ph[i];
622 
623 		switch (ph[i].p_type) {
624 		case PT_LOAD:
625 			/*
626 			 * XXX
627 			 * Can handle only 2 sections: text and data
628 			 */
629 			if (nload++ == 2)
630 				goto bad;
631 			ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
632 			    &ph[i], &addr, &size, &prot);
633 
634 			/*
635 			 * Decide whether it's text or data by looking
636 			 * at the entry point.
637 			 */
638 			if (eh->e_entry >= addr &&
639 			    eh->e_entry < (addr + size)) {
640 				epp->ep_taddr = addr;
641 				epp->ep_tsize = size;
642 				if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
643 					epp->ep_daddr = addr;
644 					epp->ep_dsize = size;
645 				}
646 			} else {
647 				epp->ep_daddr = addr;
648 				epp->ep_dsize = size;
649 			}
650 			break;
651 
652 		case PT_SHLIB:
653 #ifndef COMPAT_IBCS2			/* SCO has these sections */
654 			error = ENOEXEC;
655 			goto bad;
656 #endif
657 
658 		case PT_INTERP:
659 			/* Already did this one */
660 		case PT_DYNAMIC:
661 		case PT_NOTE:
662 			break;
663 
664 		case PT_PHDR:
665 			/* Note address of program headers (in text segment) */
666 			phdr = pp->p_vaddr;
667 			break;
668 
669 		default:
670 			/*
671 			 * Not fatal; we don't need to understand everything.
672 			 */
673 			break;
674 		}
675 	}
676 
677 	/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
678 #ifndef ELF_INTERP_NON_RELOCATABLE
679 	/*
680 	 * If no position to load the interpreter was set by a probe
681 	 * function, pick the same address that a non-fixed mmap(0, ..)
682 	 * would (i.e. something safely out of the way).
683 	 */
684 	if (pos == ELFDEFNNAME(NO_ADDR))
685 		pos = round_page(epp->ep_daddr + MAXDSIZ);
686 #endif	/* !ELF_INTERP_NON_RELOCATABLE */
687 
688 	/*
689 	 * Check if we found a dynamically linked binary and arrange to load
690 	 * it's interpreter
691 	 */
692 	if (interp[0]) {
693 		struct elf_args *ap;
694 
695 		ap = (struct elf_args *)malloc(sizeof(struct elf_args),
696 		    M_TEMP, M_WAITOK);
697 		if ((error = ELFNAME(load_file)(p, epp, interp,
698 		    &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) {
699 			free((char *)ap, M_TEMP);
700 			goto bad;
701 		}
702 		pos += phsize;
703 		ap->arg_phaddr = phdr;
704 
705 		ap->arg_phentsize = eh->e_phentsize;
706 		ap->arg_phnum = eh->e_phnum;
707 		ap->arg_entry = eh->e_entry;
708 
709 		epp->ep_emul_arg = ap;
710 	} else
711 		epp->ep_entry = eh->e_entry;
712 
713 #ifdef ELF_MAP_PAGE_ZERO
714 	/* Dell SVR4 maps page zero, yeuch! */
715 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0,
716 	    VM_PROT_READ);
717 #endif
718 	free((char *)ph, M_TEMP);
719 	epp->ep_vp->v_flag |= VTEXT;
720 	return exec_elf_setup_stack(p, epp);
721 
722 bad:
723 	free((char *)ph, M_TEMP);
724 	kill_vmcmds(&epp->ep_vmcmds);
725 	return ENOEXEC;
726 }
727 
728 static int
729 ELFNAME2(netbsd,signature)(p, epp, eh)
730 	struct proc *p;
731 	struct exec_package *epp;
732 	Elf_Ehdr *eh;
733 {
734 	Elf_Phdr *hph, *ph;
735 	Elf_Nhdr *np = NULL;
736 	size_t phsize;
737 	int error;
738 
739 	phsize = eh->e_phnum * sizeof(Elf_Phdr);
740 	hph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
741 	if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff,
742 	    (caddr_t)hph, phsize)) != 0)
743 		goto out1;
744 
745 	for (ph = hph;  ph < &hph[eh->e_phnum]; ph++) {
746 		if (ph->p_type != PT_NOTE ||
747 		    ph->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
748 			continue;
749 
750 		np = (Elf_Nhdr *)malloc(ph->p_filesz, M_TEMP, M_WAITOK);
751 		if ((error = ELFNAME(read_from)(p, epp->ep_vp, ph->p_offset,
752 		    (caddr_t)np, ph->p_filesz)) != 0)
753 			goto out2;
754 
755 		if (np->n_type != ELF_NOTE_TYPE_OSVERSION) {
756 			free(np, M_TEMP);
757 			np = NULL;
758 			continue;
759 		}
760 
761 		/* Check the name and description sizes. */
762 		if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
763 		    np->n_descsz != ELF_NOTE_NETBSD_DESCSZ)
764 			goto out3;
765 
766 		/* Is the name "NetBSD\0\0"? */
767 		if (memcmp((np + 1), ELF_NOTE_NETBSD_NAME,
768 		    ELF_NOTE_NETBSD_NAMESZ))
769 			goto out3;
770 
771 		/* XXX: We could check for the specific emulation here */
772 		/* All checks succeeded. */
773 		error = 0;
774 		goto out2;
775 	}
776 
777 out3:
778 	error = ENOEXEC;
779 out2:
780 	if (np)
781 		free(np, M_TEMP);
782 out1:
783 	free(hph, M_TEMP);
784 	return error;
785 }
786 
787 static int
788 ELFNAME2(netbsd,probe)(p, epp, eh, itp, pos)
789 	struct proc *p;
790 	struct exec_package *epp;
791 	Elf_Ehdr *eh;
792 	char *itp;
793 	Elf_Addr *pos;
794 {
795 	int error;
796 
797 	if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
798 		return error;
799 
800 	epp->ep_emul = &ELFNAMEEND(emul_netbsd);
801 	*pos = ELFDEFNNAME(NO_ADDR);
802 	return 0;
803 }
804