exec_elf32.c revision 1.57
1/*	$NetBSD: exec_elf32.c,v 1.57 2000/11/14 22:14:53 thorpej 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#include "opt_compat_netbsd32.h"
76#include "opt_syscall_debug.h"
77
78#include <sys/param.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/syscall.h>
86#include <sys/signalvar.h>
87#include <sys/mount.h>
88#include <sys/stat.h>
89
90#include <uvm/uvm_extern.h>
91
92#ifdef COMPAT_NETBSD32
93#include <compat/netbsd32/netbsd32_exec.h>
94#endif
95
96#ifdef COMPAT_LINUX
97#include <compat/linux/common/linux_exec.h>
98#endif
99
100#ifdef COMPAT_SVR4
101#include <compat/svr4/svr4_exec.h>
102#endif
103
104#ifdef COMPAT_IBCS2
105#include <compat/ibcs2/ibcs2_exec.h>
106#endif
107
108#ifdef COMPAT_FREEBSD
109#include <compat/freebsd/freebsd_exec.h>
110#endif
111
112int	ELFNAME(check_header)(Elf_Ehdr *, int);
113int	ELFNAME(load_file)(struct proc *, struct exec_package *, char *,
114	    struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *);
115void	ELFNAME(load_psection)(struct exec_vmcmd_set *, struct vnode *,
116	    const Elf_Phdr *, Elf_Addr *, u_long *, int *, int);
117
118int ELFNAME2(netbsd,signature)(struct proc *, struct exec_package *,
119    Elf_Ehdr *);
120static int ELFNAME2(netbsd,probe)(struct proc *, struct exec_package *,
121    Elf_Ehdr *, char *, Elf_Addr *);
122
123extern char sigcode[], esigcode[];
124#ifdef SYSCALL_DEBUG
125extern const char * const syscallnames[];
126#endif
127
128struct emul ELFNAMEEND(emul_netbsd) = {
129	"netbsd",
130	NULL,
131	sendsig,
132	SYS_syscall,
133	SYS_MAXSYSCALL,
134	sysent,
135#ifdef SYSCALL_DEBUG
136	syscallnames,
137#else
138	NULL,
139#endif
140	howmany(ELF_AUX_ENTRIES * sizeof(AuxInfo), sizeof (Elf_Addr)),
141	ELFNAME(copyargs),
142	setregs,
143	sigcode,
144	esigcode,
145};
146
147int (*ELFNAME(probe_funcs)[])(struct proc *, struct exec_package *,
148    Elf_Ehdr *, char *, Elf_Addr *) = {
149#if defined(COMPAT_NETBSD32) && (ELFSIZE == 32)
150	    /* This one should go first so it matches instead of netbsd */
151	ELFNAME2(netbsd32,probe),
152#endif
153	ELFNAME2(netbsd,probe),
154#if defined(COMPAT_FREEBSD) && (ELFSIZE == 32)
155	ELFNAME2(freebsd,probe),		/* XXX not 64-bit safe */
156#endif
157#if defined(COMPAT_LINUX)
158	ELFNAME2(linux,probe),
159#endif
160#if defined(COMPAT_SVR4) && (ELFSIZE == 32)
161	ELFNAME2(svr4,probe),			/* XXX not 64-bit safe */
162#endif
163#if defined(COMPAT_IBCS2) && (ELFSIZE == 32)
164	ELFNAME2(ibcs2,probe),			/* XXX not 64-bit safe */
165#endif
166};
167
168/* round up and down to page boundaries. */
169#define	ELF_ROUND(a, b)		(((a) + (b) - 1) & ~((b) - 1))
170#define	ELF_TRUNC(a, b)		((a) & ~((b) - 1))
171
172/*
173 * Copy arguments onto the stack in the normal way, but add some
174 * extra information in case of dynamic binding.
175 */
176void *
177ELFNAME(copyargs)(struct exec_package *pack, struct ps_strings *arginfo,
178    void *stack, void *argp)
179{
180	size_t len;
181	AuxInfo ai[ELF_AUX_ENTRIES], *a;
182	struct elf_args *ap;
183
184	stack = copyargs(pack, arginfo, stack, argp);
185	if (!stack)
186		return NULL;
187
188	a = ai;
189
190	/*
191	 * Push extra arguments on the stack needed by dynamically
192	 * linked binaries
193	 */
194	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
195
196		a->a_type = AT_PHDR;
197		a->a_v = ap->arg_phaddr;
198		a++;
199
200		a->a_type = AT_PHENT;
201		a->a_v = ap->arg_phentsize;
202		a++;
203
204		a->a_type = AT_PHNUM;
205		a->a_v = ap->arg_phnum;
206		a++;
207
208		a->a_type = AT_PAGESZ;
209		a->a_v = PAGE_SIZE;
210		a++;
211
212		a->a_type = AT_BASE;
213		a->a_v = ap->arg_interp;
214		a++;
215
216		a->a_type = AT_FLAGS;
217		a->a_v = 0;
218		a++;
219
220		a->a_type = AT_ENTRY;
221		a->a_v = ap->arg_entry;
222		a++;
223
224		free((char *)ap, M_TEMP);
225		pack->ep_emul_arg = NULL;
226	}
227
228	a->a_type = AT_NULL;
229	a->a_v = 0;
230	a++;
231
232	len = (a - ai) * sizeof(AuxInfo);
233	if (copyout(ai, stack, len))
234		return NULL;
235	stack = (caddr_t)stack + len;
236
237	return stack;
238}
239
240/*
241 * elf_check_header():
242 *
243 * Check header for validity; return 0 of ok ENOEXEC if error
244 */
245int
246ELFNAME(check_header)(Elf_Ehdr *eh, int type)
247{
248
249	if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
250	    eh->e_ident[EI_CLASS] != ELFCLASS)
251		return ENOEXEC;
252
253	switch (eh->e_machine) {
254
255	ELFDEFNNAME(MACHDEP_ID_CASES)
256
257	default:
258		return ENOEXEC;
259	}
260
261	if (eh->e_type != type)
262		return ENOEXEC;
263
264	return 0;
265}
266
267/*
268 * elf_load_psection():
269 *
270 * Load a psection at the appropriate address
271 */
272void
273ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp,
274    const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags)
275{
276	u_long uaddr, msize, psize, rm, rf;
277	long diff, offset;
278
279	/*
280	 * If the user specified an address, then we load there.
281	 */
282	if (*addr != ELFDEFNNAME(NO_ADDR)) {
283		if (ph->p_align > 1) {
284			*addr = ELF_TRUNC(*addr, ph->p_align);
285			uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align);
286		} else
287			uaddr = ph->p_vaddr;
288		diff = ph->p_vaddr - uaddr;
289	} else {
290		*addr = uaddr = ph->p_vaddr;
291		if (ph->p_align > 1)
292			*addr = ELF_TRUNC(uaddr, ph->p_align);
293		diff = uaddr - *addr;
294	}
295
296	*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
297	*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
298	*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
299
300	offset = ph->p_offset - diff;
301	*size = ph->p_filesz + diff;
302	msize = ph->p_memsz + diff;
303	psize = round_page(*size);
304
305	if ((ph->p_flags & PF_W) != 0) {
306		/*
307		 * Because the pagedvn pager can't handle zero fill of the last
308		 * data page if it's not page aligned we map the last page
309		 * readvn.
310		 */
311		psize = trunc_page(*size);
312	}
313	if (psize > 0) {
314		NEW_VMCMD2(vcset, vmcmd_map_pagedvn, psize, *addr, vp,
315		    offset, *prot, flags);
316	}
317	if (psize < *size) {
318		NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
319		    *addr + psize, vp, offset + psize, *prot,
320		    psize > 0 ? flags & VMCMD_RELATIVE : flags);
321	}
322
323	/*
324	 * Check if we need to extend the size of the segment
325	 */
326	rm = round_page(*addr + msize);
327	rf = round_page(*addr + *size);
328
329	if (rm != rf) {
330		NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
331		    0, *prot, flags & VMCMD_RELATIVE);
332		*size = msize;
333	}
334}
335
336/*
337 * elf_read_from():
338 *
339 *	Read from vnode into buffer at offset.
340 */
341int
342ELFNAME(read_from)(struct proc *p, struct vnode *vp, u_long off,
343    caddr_t buf, int size)
344{
345	int error;
346	size_t resid;
347
348	if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE,
349	    0, p->p_ucred, &resid, p)) != 0)
350		return error;
351	/*
352	 * See if we got all of it
353	 */
354	if (resid != 0)
355		return ENOEXEC;
356	return 0;
357}
358
359/*
360 * elf_load_file():
361 *
362 * Load a file (interpreter/library) pointed to by path
363 * [stolen from coff_load_shlib()]. Made slightly generic
364 * so it might be used externally.
365 */
366int
367ELFNAME(load_file)(struct proc *p, struct exec_package *epp, char *path,
368    struct exec_vmcmd_set *vcset, u_long *entry, struct elf_args *ap,
369    Elf_Addr *last)
370{
371	int error, i;
372	struct nameidata nd;
373	struct vnode *vp;
374	struct vattr attr;
375	Elf_Ehdr eh;
376	Elf_Phdr *ph = NULL;
377	Elf_Phdr *base_ph = NULL;
378	u_long phsize;
379	char *bp = NULL;
380	Elf_Addr addr = *last;
381
382	bp = path;
383	/*
384	 * 1. open file
385	 * 2. read filehdr
386	 * 3. map text, data, and bss out of it using VM_*
387	 */
388	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
389	if ((error = namei(&nd)) != 0)
390		return error;
391	vp = nd.ni_vp;
392
393	/*
394	 * Similarly, if it's not marked as executable, or it's not a regular
395	 * file, we don't allow it to be used.
396	 */
397	if (vp->v_type != VREG) {
398		error = EACCES;
399		goto badunlock;
400	}
401	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
402		goto badunlock;
403
404	/* get attributes */
405	if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
406		goto badunlock;
407
408	/*
409	 * Check mount point.  Though we're not trying to exec this binary,
410	 * we will be executing code from it, so if the mount point
411	 * disallows execution or set-id-ness, we punt or kill the set-id.
412	 */
413	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
414		error = EACCES;
415		goto badunlock;
416	}
417	if (vp->v_mount->mnt_flag & MNT_NOSUID)
418		epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
419
420#ifdef notyet /* XXX cgd 960926 */
421	XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
422#endif
423	VOP_UNLOCK(vp, 0);
424
425	if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh,
426	    sizeof(eh))) != 0)
427		goto bad;
428
429	if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
430		goto bad;
431
432	phsize = eh.e_phnum * sizeof(Elf_Phdr);
433	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
434
435	if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff,
436	    (caddr_t) ph, phsize)) != 0)
437		goto bad;
438
439	/*
440	 * Load all the necessary sections
441	 */
442	for (i = 0; i < eh.e_phnum; i++) {
443		u_long size = 0;
444		int prot = 0;
445		int flags;
446
447		switch (ph[i].p_type) {
448		case PT_LOAD:
449			if (base_ph == NULL) {
450				addr = *last;
451				flags = VMCMD_BASE;
452			} else {
453				addr = ph[i].p_vaddr - base_ph->p_vaddr;
454				flags = VMCMD_RELATIVE;
455			}
456			ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
457			    &size, &prot, flags);
458			/* If entry is within this section it must be text */
459			if (eh.e_entry >= ph[i].p_vaddr &&
460			    eh.e_entry < (ph[i].p_vaddr + size)) {
461				/* XXX */
462				*entry = addr + eh.e_entry;
463#ifdef mips
464				*entry -= ph[i].p_vaddr;
465#endif
466				ap->arg_interp = addr;
467			}
468			if (base_ph == NULL)
469				base_ph = &ph[i];
470			addr += size;
471			break;
472
473		case PT_DYNAMIC:
474		case PT_PHDR:
475		case PT_NOTE:
476			break;
477
478		default:
479			break;
480		}
481	}
482
483	free((char *)ph, M_TEMP);
484	*last = addr;
485	vrele(vp);
486	return 0;
487
488badunlock:
489	VOP_UNLOCK(vp, 0);
490
491bad:
492	if (ph != NULL)
493		free((char *)ph, M_TEMP);
494#ifdef notyet /* XXX cgd 960926 */
495	(maybe) VOP_CLOSE it
496#endif
497	vrele(vp);
498	return error;
499}
500
501/*
502 * exec_elf_makecmds(): Prepare an Elf binary's exec package
503 *
504 * First, set of the various offsets/lengths in the exec package.
505 *
506 * Then, mark the text image busy (so it can be demand paged) or error
507 * out if this is not possible.  Finally, set up vmcmds for the
508 * text, data, bss, and stack segments.
509 */
510int
511ELFNAME2(exec,makecmds)(struct proc *p, struct exec_package *epp)
512{
513	Elf_Ehdr *eh = epp->ep_hdr;
514	Elf_Phdr *ph, *pp;
515	Elf_Addr phdr = 0, pos = 0;
516	int error, i, n, nload;
517	char interp[MAXPATHLEN];
518	u_long phsize;
519
520	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
521		return ENOEXEC;
522
523	/*
524	 * XXX allow for executing shared objects. It seems silly
525	 * but other ELF-based systems allow it as well.
526	 */
527	if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
528	    ELFNAME(check_header)(eh, ET_DYN) != 0)
529		return ENOEXEC;
530
531	/*
532	 * check if vnode is in open for writing, because we want to
533	 * demand-page out of it.  if it is, don't do it, for various
534	 * reasons
535	 */
536	if (epp->ep_vp->v_writecount != 0) {
537#ifdef DIAGNOSTIC
538		if (epp->ep_vp->v_flag & VTEXT)
539			panic("exec: a VTEXT vnode has writecount != 0\n");
540#endif
541		return ETXTBSY;
542	}
543	/*
544	 * Allocate space to hold all the program headers, and read them
545	 * from the file
546	 */
547	phsize = eh->e_phnum * sizeof(Elf_Phdr);
548	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
549
550	if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff,
551	    (caddr_t) ph, phsize)) != 0)
552		goto bad;
553
554	epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
555	epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
556
557	interp[0] = '\0';
558
559	for (i = 0; i < eh->e_phnum; i++) {
560		pp = &ph[i];
561		if (pp->p_type == PT_INTERP) {
562			if (pp->p_filesz >= sizeof(interp))
563				goto bad;
564			if ((error = ELFNAME(read_from)(p, epp->ep_vp,
565			    pp->p_offset, (caddr_t) interp,
566			    pp->p_filesz)) != 0)
567				goto bad;
568			break;
569		}
570	}
571
572	/*
573	 * Setup things for native emulation.
574	 */
575	epp->ep_emul = &ELFNAMEEND(emul_netbsd);
576	pos = ELFDEFNNAME(NO_ADDR);
577
578	/*
579	 * On the same architecture, we may be emulating different systems.
580	 * See which one will accept this executable. This currently only
581	 * applies to SVR4, and IBCS2 on the i386 and Linux on the i386
582	 * and the Alpha.
583	 *
584	 * Probe functions would normally see if the interpreter (if any)
585	 * exists. Emulation packages may possibly replace the interpreter in
586	 * interp[] with a changed path (/emul/xxx/<path>), and also
587	 * set the ep_emul field in the exec package structure.
588	 */
589	n = sizeof(ELFNAME(probe_funcs)) / sizeof(ELFNAME(probe_funcs)[0]);
590	if (n != 0) {
591		error = ENOEXEC;
592		for (i = 0; i < n && error; i++)
593			error = ELFNAME(probe_funcs)[i](p, epp, eh,
594			    interp, &pos);
595#ifdef notyet
596		/*
597		 * We should really use a signature in our native binaries
598		 * and have our own probe function for matching binaries,
599		 * before trying the emulations. For now, if the emulation
600		 * probes failed we default to native.
601		 */
602		if (error)
603			goto bad;
604#endif
605	}
606
607	/*
608	 * Load all the necessary sections
609	 */
610	for (i = nload = 0; i < eh->e_phnum; i++) {
611		Elf_Addr  addr = ELFDEFNNAME(NO_ADDR);
612		u_long size = 0;
613		int prot = 0;
614
615		pp = &ph[i];
616
617		switch (ph[i].p_type) {
618		case PT_LOAD:
619			/*
620			 * XXX
621			 * Can handle only 2 sections: text and data
622			 */
623			if (nload++ == 2)
624				goto bad;
625			ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
626			    &ph[i], &addr, &size, &prot, 0);
627
628			/*
629			 * Decide whether it's text or data by looking
630			 * at the entry point.
631			 */
632			if (eh->e_entry >= addr &&
633			    eh->e_entry < (addr + size)) {
634				epp->ep_taddr = addr;
635				epp->ep_tsize = size;
636				if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
637					epp->ep_daddr = addr;
638					epp->ep_dsize = size;
639				}
640			} else {
641				epp->ep_daddr = addr;
642				epp->ep_dsize = size;
643			}
644			break;
645
646		case PT_SHLIB:
647#ifndef COMPAT_IBCS2			/* SCO has these sections */
648			error = ENOEXEC;
649			goto bad;
650#endif
651
652		case PT_INTERP:
653			/* Already did this one */
654		case PT_DYNAMIC:
655		case PT_NOTE:
656			break;
657
658		case PT_PHDR:
659			/* Note address of program headers (in text segment) */
660			phdr = pp->p_vaddr;
661			break;
662
663		default:
664			/*
665			 * Not fatal; we don't need to understand everything.
666			 */
667			break;
668		}
669	}
670
671	/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
672#ifndef ELF_INTERP_NON_RELOCATABLE
673	/*
674	 * If no position to load the interpreter was set by a probe
675	 * function, pick the same address that a non-fixed mmap(0, ..)
676	 * would (i.e. something safely out of the way).
677	 */
678	if (pos == ELFDEFNNAME(NO_ADDR))
679		pos = round_page(epp->ep_daddr + MAXDSIZ);
680#endif	/* !ELF_INTERP_NON_RELOCATABLE */
681
682	/*
683	 * Check if we found a dynamically linked binary and arrange to load
684	 * it's interpreter
685	 */
686	if (interp[0]) {
687		struct elf_args *ap;
688
689		ap = (struct elf_args *)malloc(sizeof(struct elf_args),
690		    M_TEMP, M_WAITOK);
691		if ((error = ELFNAME(load_file)(p, epp, interp,
692		    &epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) {
693			free((char *)ap, M_TEMP);
694			goto bad;
695		}
696		pos += phsize;
697		ap->arg_phaddr = phdr;
698
699		ap->arg_phentsize = eh->e_phentsize;
700		ap->arg_phnum = eh->e_phnum;
701		ap->arg_entry = eh->e_entry;
702
703		epp->ep_emul_arg = ap;
704	} else
705		epp->ep_entry = eh->e_entry;
706
707#ifdef ELF_MAP_PAGE_ZERO
708	/* Dell SVR4 maps page zero, yeuch! */
709	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
710	    epp->ep_vp, 0, VM_PROT_READ);
711#endif
712	free((char *)ph, M_TEMP);
713	vn_marktext(epp->ep_vp);
714	return exec_elf_setup_stack(p, epp);
715
716bad:
717	free((char *)ph, M_TEMP);
718	kill_vmcmds(&epp->ep_vmcmds);
719	return ENOEXEC;
720}
721
722int
723ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp,
724    Elf_Ehdr *eh)
725{
726	Elf_Phdr *hph, *ph;
727	Elf_Nhdr *np = NULL;
728	size_t phsize;
729	int error;
730
731	phsize = eh->e_phnum * sizeof(Elf_Phdr);
732	hph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
733	if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff,
734	    (caddr_t)hph, phsize)) != 0)
735		goto out1;
736
737	for (ph = hph;  ph < &hph[eh->e_phnum]; ph++) {
738		if (ph->p_type != PT_NOTE ||
739		    ph->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
740			continue;
741
742		np = (Elf_Nhdr *)malloc(ph->p_filesz, M_TEMP, M_WAITOK);
743		if ((error = ELFNAME(read_from)(p, epp->ep_vp, ph->p_offset,
744		    (caddr_t)np, ph->p_filesz)) != 0)
745			goto out2;
746
747		if (np->n_type != ELF_NOTE_TYPE_OSVERSION) {
748			free(np, M_TEMP);
749			np = NULL;
750			continue;
751		}
752
753		/* Check the name and description sizes. */
754		if (np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
755		    np->n_descsz != ELF_NOTE_NETBSD_DESCSZ)
756			goto out3;
757
758		/* Is the name "NetBSD\0\0"? */
759		if (memcmp((np + 1), ELF_NOTE_NETBSD_NAME,
760		    ELF_NOTE_NETBSD_NAMESZ))
761			goto out3;
762
763		/* XXX: We could check for the specific emulation here */
764		/* All checks succeeded. */
765		error = 0;
766		goto out2;
767	}
768
769out3:
770	error = ENOEXEC;
771out2:
772	if (np)
773		free(np, M_TEMP);
774out1:
775	free(hph, M_TEMP);
776	return error;
777}
778
779static int
780ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp,
781    Elf_Ehdr *eh, char *itp, Elf_Addr *pos)
782{
783	int error;
784
785	if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
786		return error;
787	epp->ep_emul = &ELFNAMEEND(emul_netbsd);
788	*pos = ELFDEFNNAME(NO_ADDR);
789	return 0;
790}
791