exec_elf32.c revision 1.88
1/*	$NetBSD: exec_elf32.c,v 1.88 2003/02/28 19:44:42 matt Exp $	*/
2
3/*-
4 * Copyright (c) 1994, 2000 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#include <sys/cdefs.h>
67__KERNEL_RCSID(1, "$NetBSD: exec_elf32.c,v 1.88 2003/02/28 19:44:42 matt Exp $");
68
69/* If not included by exec_elf64.c, ELFSIZE won't be defined. */
70#ifndef ELFSIZE
71#define	ELFSIZE		32
72#endif
73
74#include <sys/param.h>
75#include <sys/proc.h>
76#include <sys/malloc.h>
77#include <sys/namei.h>
78#include <sys/vnode.h>
79#include <sys/exec.h>
80#include <sys/exec_elf.h>
81#include <sys/syscall.h>
82#include <sys/signalvar.h>
83#include <sys/mount.h>
84#include <sys/stat.h>
85
86#include <machine/cpu.h>
87#include <machine/reg.h>
88
89extern const struct emul emul_netbsd;
90
91int	ELFNAME(check_header)(Elf_Ehdr *, int);
92int	ELFNAME(load_file)(struct proc *, struct exec_package *, char *,
93	    struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *);
94void	ELFNAME(load_psection)(struct exec_vmcmd_set *, struct vnode *,
95	    const Elf_Phdr *, Elf_Addr *, u_long *, int *, int);
96
97int ELFNAME2(netbsd,signature)(struct proc *, struct exec_package *,
98    Elf_Ehdr *);
99int ELFNAME2(netbsd,probe)(struct proc *, struct exec_package *,
100    void *, char *, vaddr_t *);
101
102/* round up and down to page boundaries. */
103#define	ELF_ROUND(a, b)		(((a) + (b) - 1) & ~((b) - 1))
104#define	ELF_TRUNC(a, b)		((a) & ~((b) - 1))
105
106/*
107 * Copy arguments onto the stack in the normal way, but add some
108 * extra information in case of dynamic binding.
109 */
110int
111ELFNAME(copyargs)(struct proc *p, struct exec_package *pack,
112    struct ps_strings *arginfo, char **stackp, void *argp)
113{
114	size_t len;
115	AuxInfo ai[ELF_AUX_ENTRIES], *a;
116	struct elf_args *ap;
117	int error;
118
119	if ((error = copyargs(p, pack, arginfo, stackp, argp)) != 0)
120		return error;
121
122	a = ai;
123
124	/*
125	 * Push extra arguments on the stack needed by dynamically
126	 * linked binaries
127	 */
128	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
129		struct vattr *vap = pack->ep_vap;
130
131		a->a_type = AT_PHDR;
132		a->a_v = ap->arg_phaddr;
133		a++;
134
135		a->a_type = AT_PHENT;
136		a->a_v = ap->arg_phentsize;
137		a++;
138
139		a->a_type = AT_PHNUM;
140		a->a_v = ap->arg_phnum;
141		a++;
142
143		a->a_type = AT_PAGESZ;
144		a->a_v = PAGE_SIZE;
145		a++;
146
147		a->a_type = AT_BASE;
148		a->a_v = ap->arg_interp;
149		a++;
150
151		a->a_type = AT_FLAGS;
152		a->a_v = 0;
153		a++;
154
155		a->a_type = AT_ENTRY;
156		a->a_v = ap->arg_entry;
157		a++;
158
159		a->a_type = AT_EUID;
160		if (vap->va_mode & S_ISUID)
161			a->a_v = vap->va_uid;
162		else
163			a->a_v = p->p_ucred->cr_uid;
164		a++;
165
166		a->a_type = AT_RUID;
167		a->a_v = p->p_cred->p_ruid;
168		a++;
169
170		a->a_type = AT_EGID;
171		if (vap->va_mode & S_ISGID)
172			a->a_v = vap->va_gid;
173		else
174			a->a_v = p->p_ucred->cr_gid;
175		a++;
176
177		a->a_type = AT_RGID;
178		a->a_v = p->p_cred->p_rgid;
179		a++;
180
181		free(ap, M_TEMP);
182		pack->ep_emul_arg = NULL;
183	}
184
185	a->a_type = AT_NULL;
186	a->a_v = 0;
187	a++;
188
189	len = (a - ai) * sizeof(AuxInfo);
190	if ((error = copyout(ai, *stackp, len)) != 0)
191		return error;
192	*stackp += len;
193
194	return 0;
195}
196
197/*
198 * elf_check_header():
199 *
200 * Check header for validity; return 0 of ok ENOEXEC if error
201 */
202int
203ELFNAME(check_header)(Elf_Ehdr *eh, int type)
204{
205
206	if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
207	    eh->e_ident[EI_CLASS] != ELFCLASS)
208		return (ENOEXEC);
209
210	switch (eh->e_machine) {
211
212	ELFDEFNNAME(MACHDEP_ID_CASES)
213
214	default:
215		return (ENOEXEC);
216	}
217
218	if (ELF_EHDR_FLAGS_OK(eh) == 0)
219		return (ENOEXEC);
220
221	if (eh->e_type != type)
222		return (ENOEXEC);
223
224	if (eh->e_shnum > 512 ||
225	    eh->e_phnum > 128)
226		return (ENOEXEC);
227
228	return (0);
229}
230
231/*
232 * elf_load_psection():
233 *
234 * Load a psection at the appropriate address
235 */
236void
237ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp,
238    const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags)
239{
240	u_long msize, psize, rm, rf;
241	long diff, offset;
242
243	/*
244	 * If the user specified an address, then we load there.
245	 */
246	if (*addr == ELFDEFNNAME(NO_ADDR))
247		*addr = ph->p_vaddr;
248
249	if (ph->p_align > 1) {
250		/*
251		 * Make sure we are virtually aligned as we are supposed to be.
252		 */
253		diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
254		KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align));
255		/*
256		 * But make sure to not map any pages before the start of the
257		 * psection by limiting the difference to within a page.
258		 */
259		diff &= PAGE_MASK;
260	} else
261		diff = 0;
262
263	*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
264	*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
265	*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
266
267	/*
268	 * Adjust everything so it all starts on a page boundary.
269	 */
270	*addr -= diff;
271	offset = ph->p_offset - diff;
272	*size = ph->p_filesz + diff;
273	msize = ph->p_memsz + diff;
274
275	if (ph->p_align >= PAGE_SIZE) {
276		if ((ph->p_flags & PF_W) != 0) {
277			/*
278			 * Because the pagedvn pager can't handle zero fill
279			 * of the last data page if it's not page aligned we
280			 * map the last page readvn.
281			 */
282			psize = trunc_page(*size);
283		} else {
284			psize = round_page(*size);
285		}
286	} else {
287		psize = *size;
288	}
289
290	if (psize > 0) {
291		NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ?
292		    vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp,
293		    offset, *prot, flags);
294		flags &= VMCMD_RELATIVE;
295	}
296	if (psize < *size) {
297		NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
298		    *addr + psize, vp, offset + psize, *prot, flags);
299	}
300
301	/*
302	 * Check if we need to extend the size of the segment (does
303	 * bss extend page the next page boundary)?
304	 */
305	rm = round_page(*addr + msize);
306	rf = round_page(*addr + *size);
307
308	if (rm != rf) {
309		NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
310		    0, *prot, flags & VMCMD_RELATIVE);
311		*size = msize;
312	}
313}
314
315/*
316 * elf_load_file():
317 *
318 * Load a file (interpreter/library) pointed to by path
319 * [stolen from coff_load_shlib()]. Made slightly generic
320 * so it might be used externally.
321 */
322int
323ELFNAME(load_file)(struct proc *p, struct exec_package *epp, char *path,
324    struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap,
325    Elf_Addr *last)
326{
327	int error, i;
328	struct nameidata nd;
329	struct vnode *vp;
330	struct vattr attr;
331	Elf_Ehdr eh;
332	Elf_Phdr *ph = NULL;
333	const Elf_Phdr *ph0;
334	const Elf_Phdr *base_ph;
335	const Elf_Phdr *last_ph;
336	u_long phsize;
337	Elf_Addr addr = *last;
338
339	/*
340	 * 1. open file
341	 * 2. read filehdr
342	 * 3. map text, data, and bss out of it using VM_*
343	 */
344	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
345	if ((error = namei(&nd)) != 0)
346		return error;
347	vp = nd.ni_vp;
348
349	/*
350	 * Similarly, if it's not marked as executable, or it's not a regular
351	 * file, we don't allow it to be used.
352	 */
353	if (vp->v_type != VREG) {
354		error = EACCES;
355		goto badunlock;
356	}
357	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
358		goto badunlock;
359
360	/* get attributes */
361	if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
362		goto badunlock;
363
364	/*
365	 * Check mount point.  Though we're not trying to exec this binary,
366	 * we will be executing code from it, so if the mount point
367	 * disallows execution or set-id-ness, we punt or kill the set-id.
368	 */
369	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
370		error = EACCES;
371		goto badunlock;
372	}
373	if (vp->v_mount->mnt_flag & MNT_NOSUID)
374		epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
375
376#ifdef notyet /* XXX cgd 960926 */
377	XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
378#endif
379
380	error = vn_marktext(vp);
381	if (error)
382		goto badunlock;
383
384	VOP_UNLOCK(vp, 0);
385
386	if ((error = exec_read_from(p, vp, 0, &eh, sizeof(eh))) != 0)
387		goto bad;
388
389	if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
390		goto bad;
391
392	phsize = eh.e_phnum * sizeof(Elf_Phdr);
393	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
394
395	if ((error = exec_read_from(p, vp, eh.e_phoff, ph, phsize)) != 0)
396		goto bad;
397
398	/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
399#ifndef ELF_INTERP_NON_RELOCATABLE
400	/*
401	 * If no position to load the interpreter was set by a probe
402	 * function, pick the same address that a non-fixed mmap(0, ..)
403	 * would (i.e. something safely out of the way).
404	 */
405	if (*last == ELFDEFNNAME(NO_ADDR)) {
406		u_long limit = 0;
407		/*
408		 * Find the start and ending addresses of the psections to
409		 * be loaded.  This will give us the size.
410		 */
411		for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum;
412		     i++, ph0++) {
413			if (ph0->p_type == PT_LOAD) {
414				u_long psize = ph0->p_vaddr + ph0->p_memsz;
415				if (base_ph == NULL)
416					base_ph = ph0;
417				if (psize > limit)
418					limit = psize;
419			}
420		}
421
422		/*
423		 * Now compute the size and load address.
424		 */
425		addr = VM_DEFAULT_ADDRESS(epp->ep_daddr,
426		    round_page(limit) - trunc_page(base_ph->p_vaddr));
427	} else
428#endif	/* !ELF_INTERP_NON_RELOCATABLE */
429		addr = *last;
430
431	/*
432	 * Load all the necessary sections
433	 */
434	for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL;
435	     i < eh.e_phnum; i++, ph0++) {
436		switch (ph0->p_type) {
437		case PT_LOAD: {
438			u_long size;
439			int prot = 0;
440			int flags;
441
442			if (base_ph == NULL) {
443				/*
444				 * First encountered psection is always the
445				 * base psection.  Make sure it's aligned
446				 * properly.
447				 */
448				base_ph = ph0;
449				flags = VMCMD_BASE;
450				addr = ELF_TRUNC(addr + ph0->p_align - 1,
451				    ph0->p_align);
452			} else {
453				u_long limit = round_page(last_ph->p_vaddr
454				    + last_ph->p_memsz);
455				u_long base = trunc_page(ph0->p_vaddr);
456
457				/*
458				 * If there is a gap in between the psections,
459				 * map it as inaccessible so nothing else
460				 * mmap'ed will be placed there.
461				 */
462				if (limit != base) {
463					NEW_VMCMD2(vcset, vmcmd_map_zero,
464					    base - limit,
465					    limit - base_ph->p_vaddr, NULLVP,
466					    0, VM_PROT_NONE, VMCMD_RELATIVE);
467				}
468
469				addr = ph0->p_vaddr - base_ph->p_vaddr;
470				flags = VMCMD_RELATIVE;
471			}
472			last_ph = ph0;
473			ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
474			    &size, &prot, flags);
475			/*
476			 * If entry is within this psection then this
477			 * must contain the .text section.  *entryoff is
478			 * relative to the base psection.
479			 */
480			if (eh.e_entry >= ph0->p_vaddr &&
481			    eh.e_entry < (ph0->p_vaddr + size)) {
482				*entryoff = eh.e_entry - base_ph->p_vaddr;
483			}
484			addr += size;
485			break;
486		}
487
488		case PT_DYNAMIC:
489		case PT_PHDR:
490		case PT_NOTE:
491			break;
492
493		default:
494			break;
495		}
496	}
497
498	free(ph, M_TEMP);
499	/*
500	 * This value is ignored if TOPDOWN.
501	 */
502	*last = addr;
503	vrele(vp);
504	return 0;
505
506badunlock:
507	VOP_UNLOCK(vp, 0);
508
509bad:
510	if (ph != NULL)
511		free(ph, M_TEMP);
512#ifdef notyet /* XXX cgd 960926 */
513	(maybe) VOP_CLOSE it
514#endif
515	vrele(vp);
516	return error;
517}
518
519/*
520 * exec_elf_makecmds(): Prepare an Elf binary's exec package
521 *
522 * First, set of the various offsets/lengths in the exec package.
523 *
524 * Then, mark the text image busy (so it can be demand paged) or error
525 * out if this is not possible.  Finally, set up vmcmds for the
526 * text, data, bss, and stack segments.
527 */
528int
529ELFNAME2(exec,makecmds)(struct proc *p, struct exec_package *epp)
530{
531	Elf_Ehdr *eh = epp->ep_hdr;
532	Elf_Phdr *ph, *pp;
533	Elf_Addr phdr = 0, pos = 0;
534	int error, i, nload;
535	char *interp = NULL;
536	u_long phsize;
537
538	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
539		return ENOEXEC;
540
541	/*
542	 * XXX allow for executing shared objects. It seems silly
543	 * but other ELF-based systems allow it as well.
544	 */
545	if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
546	    ELFNAME(check_header)(eh, ET_DYN) != 0)
547		return ENOEXEC;
548
549	error = vn_marktext(epp->ep_vp);
550	if (error)
551		return (error);
552
553	/*
554	 * Allocate space to hold all the program headers, and read them
555	 * from the file
556	 */
557	phsize = eh->e_phnum * sizeof(Elf_Phdr);
558	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
559
560	if ((error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) !=
561	    0)
562		goto bad;
563
564	epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
565	epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
566
567	MALLOC(interp, char *, MAXPATHLEN, M_TEMP, M_WAITOK);
568	interp[0] = '\0';
569
570	for (i = 0; i < eh->e_phnum; i++) {
571		pp = &ph[i];
572		if (pp->p_type == PT_INTERP) {
573			if (pp->p_filesz >= MAXPATHLEN)
574				goto bad;
575			if ((error = exec_read_from(p, epp->ep_vp,
576			    pp->p_offset, interp, pp->p_filesz)) != 0)
577				goto bad;
578			break;
579		}
580	}
581
582	/*
583	 * On the same architecture, we may be emulating different systems.
584	 * See which one will accept this executable. This currently only
585	 * applies to SVR4, and IBCS2 on the i386 and Linux on the i386
586	 * and the Alpha.
587	 *
588	 * Probe functions would normally see if the interpreter (if any)
589	 * exists. Emulation packages may possibly replace the interpreter in
590	 * interp[] with a changed path (/emul/xxx/<path>).
591	 */
592	if (!epp->ep_esch->u.elf_probe_func) {
593		pos = ELFDEFNNAME(NO_ADDR);
594	} else {
595		vaddr_t startp = 0;
596
597		error = (*epp->ep_esch->u.elf_probe_func)(p, epp, eh, interp,
598							  &startp);
599		pos = (Elf_Addr)startp;
600		if (error)
601			goto bad;
602	}
603
604	/*
605	 * Load all the necessary sections
606	 */
607	for (i = nload = 0; i < eh->e_phnum; i++) {
608		Elf_Addr  addr = ELFDEFNNAME(NO_ADDR);
609		u_long size = 0;
610		int prot = 0;
611
612		pp = &ph[i];
613
614		switch (ph[i].p_type) {
615		case PT_LOAD:
616			/*
617			 * XXX
618			 * Can handle only 2 sections: text and data
619			 */
620			if (nload++ == 2)
621				goto bad;
622			ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
623			    &ph[i], &addr, &size, &prot, VMCMD_FIXED);
624
625			/*
626			 * Decide whether it's text or data by looking
627			 * at the entry point.
628			 */
629			if (eh->e_entry >= addr &&
630			    eh->e_entry < (addr + size)) {
631				epp->ep_taddr = addr;
632				epp->ep_tsize = size;
633				if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
634					epp->ep_daddr = addr;
635					epp->ep_dsize = size;
636				}
637			} else {
638				epp->ep_daddr = addr;
639				epp->ep_dsize = size;
640			}
641			break;
642
643		case PT_SHLIB:
644			/* SCO has these sections. */
645		case PT_INTERP:
646			/* Already did this one. */
647		case PT_DYNAMIC:
648		case PT_NOTE:
649			break;
650
651		case PT_PHDR:
652			/* Note address of program headers (in text segment) */
653			phdr = pp->p_vaddr;
654			break;
655
656		default:
657			/*
658			 * Not fatal; we don't need to understand everything.
659			 */
660			break;
661		}
662	}
663
664	/*
665	 * Check if we found a dynamically linked binary and arrange to load
666	 * its interpreter
667	 */
668	if (interp[0]) {
669		struct elf_args *ap;
670		int i = epp->ep_vmcmds.evs_used;
671		u_long interp_offset;
672
673		MALLOC(ap, struct elf_args *, sizeof(struct elf_args),
674		    M_TEMP, M_WAITOK);
675		if ((error = ELFNAME(load_file)(p, epp, interp,
676		    &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) {
677			FREE(ap, M_TEMP);
678			goto bad;
679		}
680		ap->arg_interp = epp->ep_vmcmds.evs_cmds[i].ev_addr;
681		epp->ep_entry = ap->arg_interp + interp_offset;
682		ap->arg_phaddr = phdr;
683
684		ap->arg_phentsize = eh->e_phentsize;
685		ap->arg_phnum = eh->e_phnum;
686		ap->arg_entry = eh->e_entry;
687
688		epp->ep_emul_arg = ap;
689	} else
690		epp->ep_entry = eh->e_entry;
691
692#ifdef ELF_MAP_PAGE_ZERO
693	/* Dell SVR4 maps page zero, yeuch! */
694	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
695	    epp->ep_vp, 0, VM_PROT_READ);
696#endif
697	FREE(interp, M_TEMP);
698	free(ph, M_TEMP);
699	return exec_elf_setup_stack(p, epp);
700
701bad:
702	if (interp)
703		FREE(interp, M_TEMP);
704	free(ph, M_TEMP);
705	kill_vmcmds(&epp->ep_vmcmds);
706	return ENOEXEC;
707}
708
709int
710ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp,
711    Elf_Ehdr *eh)
712{
713	size_t i;
714	Elf_Phdr *ph;
715	size_t phsize;
716	int error;
717
718	phsize = eh->e_phnum * sizeof(Elf_Phdr);
719	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
720	error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize);
721	if (error)
722		goto out;
723
724	for (i = 0; i < eh->e_phnum; i++) {
725		Elf_Phdr *ephp = &ph[i];
726		Elf_Nhdr *np;
727
728		if (ephp->p_type != PT_NOTE ||
729		    ephp->p_filesz > 1024 ||
730		    ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
731			continue;
732
733		np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
734		error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np,
735		    ephp->p_filesz);
736		if (error)
737			goto next;
738
739		if (np->n_type != ELF_NOTE_TYPE_NETBSD_TAG ||
740		    np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
741		    np->n_descsz != ELF_NOTE_NETBSD_DESCSZ ||
742		    memcmp((caddr_t)(np + 1), ELF_NOTE_NETBSD_NAME,
743		    ELF_NOTE_NETBSD_NAMESZ))
744			goto next;
745
746		error = 0;
747		free(np, M_TEMP);
748		goto out;
749
750	next:
751		free(np, M_TEMP);
752		continue;
753	}
754
755	error = ENOEXEC;
756out:
757	free(ph, M_TEMP);
758	return (error);
759}
760
761int
762ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp,
763    void *eh, char *itp, vaddr_t *pos)
764{
765	int error;
766
767	if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
768		return error;
769	*pos = ELFDEFNNAME(NO_ADDR);
770	return 0;
771}
772