exec_elf32.c revision 1.90
1/*	$NetBSD: exec_elf32.c,v 1.90 2003/06/25 13:48:06 christos 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 1.90 2003/06/25 13:48:06 christos 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#define MAXPHNUM	50
107
108/*
109 * Copy arguments onto the stack in the normal way, but add some
110 * extra information in case of dynamic binding.
111 */
112int
113ELFNAME(copyargs)(struct proc *p, struct exec_package *pack,
114    struct ps_strings *arginfo, char **stackp, void *argp)
115{
116	size_t len;
117	AuxInfo ai[ELF_AUX_ENTRIES], *a;
118	struct elf_args *ap;
119	int error;
120
121	if ((error = copyargs(p, pack, arginfo, stackp, argp)) != 0)
122		return error;
123
124	a = ai;
125
126	/*
127	 * Push extra arguments on the stack needed by dynamically
128	 * linked binaries
129	 */
130	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
131		struct vattr *vap = pack->ep_vap;
132
133		a->a_type = AT_PHDR;
134		a->a_v = ap->arg_phaddr;
135		a++;
136
137		a->a_type = AT_PHENT;
138		a->a_v = ap->arg_phentsize;
139		a++;
140
141		a->a_type = AT_PHNUM;
142		a->a_v = ap->arg_phnum;
143		a++;
144
145		a->a_type = AT_PAGESZ;
146		a->a_v = PAGE_SIZE;
147		a++;
148
149		a->a_type = AT_BASE;
150		a->a_v = ap->arg_interp;
151		a++;
152
153		a->a_type = AT_FLAGS;
154		a->a_v = 0;
155		a++;
156
157		a->a_type = AT_ENTRY;
158		a->a_v = ap->arg_entry;
159		a++;
160
161		a->a_type = AT_EUID;
162		if (vap->va_mode & S_ISUID)
163			a->a_v = vap->va_uid;
164		else
165			a->a_v = p->p_ucred->cr_uid;
166		a++;
167
168		a->a_type = AT_RUID;
169		a->a_v = p->p_cred->p_ruid;
170		a++;
171
172		a->a_type = AT_EGID;
173		if (vap->va_mode & S_ISGID)
174			a->a_v = vap->va_gid;
175		else
176			a->a_v = p->p_ucred->cr_gid;
177		a++;
178
179		a->a_type = AT_RGID;
180		a->a_v = p->p_cred->p_rgid;
181		a++;
182
183		free(ap, M_TEMP);
184		pack->ep_emul_arg = NULL;
185	}
186
187	a->a_type = AT_NULL;
188	a->a_v = 0;
189	a++;
190
191	len = (a - ai) * sizeof(AuxInfo);
192	if ((error = copyout(ai, *stackp, len)) != 0)
193		return error;
194	*stackp += len;
195
196	return 0;
197}
198
199/*
200 * elf_check_header():
201 *
202 * Check header for validity; return 0 of ok ENOEXEC if error
203 */
204int
205ELFNAME(check_header)(Elf_Ehdr *eh, int type)
206{
207
208	if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
209	    eh->e_ident[EI_CLASS] != ELFCLASS)
210		return (ENOEXEC);
211
212	switch (eh->e_machine) {
213
214	ELFDEFNNAME(MACHDEP_ID_CASES)
215
216	default:
217		return (ENOEXEC);
218	}
219
220	if (ELF_EHDR_FLAGS_OK(eh) == 0)
221		return (ENOEXEC);
222
223	if (eh->e_type != type)
224		return (ENOEXEC);
225
226	if (eh->e_shnum > 512 ||
227	    eh->e_phnum > 128)
228		return (ENOEXEC);
229
230	return (0);
231}
232
233/*
234 * elf_load_psection():
235 *
236 * Load a psection at the appropriate address
237 */
238void
239ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp,
240    const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags)
241{
242	u_long msize, psize, rm, rf;
243	long diff, offset;
244
245	/*
246	 * If the user specified an address, then we load there.
247	 */
248	if (*addr == ELFDEFNNAME(NO_ADDR))
249		*addr = ph->p_vaddr;
250
251	if (ph->p_align > 1) {
252		/*
253		 * Make sure we are virtually aligned as we are supposed to be.
254		 */
255		diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
256		KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align));
257		/*
258		 * But make sure to not map any pages before the start of the
259		 * psection by limiting the difference to within a page.
260		 */
261		diff &= PAGE_MASK;
262	} else
263		diff = 0;
264
265	*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
266	*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
267	*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
268
269	/*
270	 * Adjust everything so it all starts on a page boundary.
271	 */
272	*addr -= diff;
273	offset = ph->p_offset - diff;
274	*size = ph->p_filesz + diff;
275	msize = ph->p_memsz + diff;
276
277	if (ph->p_align >= PAGE_SIZE) {
278		if ((ph->p_flags & PF_W) != 0) {
279			/*
280			 * Because the pagedvn pager can't handle zero fill
281			 * of the last data page if it's not page aligned we
282			 * map the last page readvn.
283			 */
284			psize = trunc_page(*size);
285		} else {
286			psize = round_page(*size);
287		}
288	} else {
289		psize = *size;
290	}
291
292	if (psize > 0) {
293		NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ?
294		    vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp,
295		    offset, *prot, flags);
296		flags &= VMCMD_RELATIVE;
297	}
298	if (psize < *size) {
299		NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
300		    *addr + psize, vp, offset + psize, *prot, flags);
301	}
302
303	/*
304	 * Check if we need to extend the size of the segment (does
305	 * bss extend page the next page boundary)?
306	 */
307	rm = round_page(*addr + msize);
308	rf = round_page(*addr + *size);
309
310	if (rm != rf) {
311		NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
312		    0, *prot, flags & VMCMD_RELATIVE);
313		*size = msize;
314	}
315}
316
317/*
318 * elf_load_file():
319 *
320 * Load a file (interpreter/library) pointed to by path
321 * [stolen from coff_load_shlib()]. Made slightly generic
322 * so it might be used externally.
323 */
324int
325ELFNAME(load_file)(struct proc *p, struct exec_package *epp, char *path,
326    struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap,
327    Elf_Addr *last)
328{
329	int error, i;
330	struct nameidata nd;
331	struct vnode *vp;
332	struct vattr attr;
333	Elf_Ehdr eh;
334	Elf_Phdr *ph = NULL;
335	const Elf_Phdr *ph0;
336	const Elf_Phdr *base_ph;
337	const Elf_Phdr *last_ph;
338	u_long phsize;
339	Elf_Addr addr = *last;
340
341	/*
342	 * 1. open file
343	 * 2. read filehdr
344	 * 3. map text, data, and bss out of it using VM_*
345	 */
346	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
347	if ((error = namei(&nd)) != 0)
348		return error;
349	vp = nd.ni_vp;
350
351	/*
352	 * Similarly, if it's not marked as executable, or it's not a regular
353	 * file, we don't allow it to be used.
354	 */
355	if (vp->v_type != VREG) {
356		error = EACCES;
357		goto badunlock;
358	}
359	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
360		goto badunlock;
361
362	/* get attributes */
363	if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
364		goto badunlock;
365
366	/*
367	 * Check mount point.  Though we're not trying to exec this binary,
368	 * we will be executing code from it, so if the mount point
369	 * disallows execution or set-id-ness, we punt or kill the set-id.
370	 */
371	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
372		error = EACCES;
373		goto badunlock;
374	}
375	if (vp->v_mount->mnt_flag & MNT_NOSUID)
376		epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
377
378#ifdef notyet /* XXX cgd 960926 */
379	XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
380#endif
381
382	error = vn_marktext(vp);
383	if (error)
384		goto badunlock;
385
386	VOP_UNLOCK(vp, 0);
387
388	if ((error = exec_read_from(p, vp, 0, &eh, sizeof(eh))) != 0)
389		goto bad;
390
391	if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
392		goto bad;
393
394	if (eh.e_phnum > MAXPHNUM)
395		goto bad;
396
397	phsize = eh.e_phnum * sizeof(Elf_Phdr);
398	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
399
400	if ((error = exec_read_from(p, vp, eh.e_phoff, ph, phsize)) != 0)
401		goto bad;
402
403	/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
404#ifndef ELF_INTERP_NON_RELOCATABLE
405	/*
406	 * If no position to load the interpreter was set by a probe
407	 * function, pick the same address that a non-fixed mmap(0, ..)
408	 * would (i.e. something safely out of the way).
409	 */
410	if (*last == ELFDEFNNAME(NO_ADDR)) {
411		u_long limit = 0;
412		/*
413		 * Find the start and ending addresses of the psections to
414		 * be loaded.  This will give us the size.
415		 */
416		for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum;
417		     i++, ph0++) {
418			if (ph0->p_type == PT_LOAD) {
419				u_long psize = ph0->p_vaddr + ph0->p_memsz;
420				if (base_ph == NULL)
421					base_ph = ph0;
422				if (psize > limit)
423					limit = psize;
424			}
425		}
426
427		/*
428		 * Now compute the size and load address.
429		 */
430		addr = VM_DEFAULT_ADDRESS(epp->ep_daddr,
431		    round_page(limit) - trunc_page(base_ph->p_vaddr));
432	} else
433#endif	/* !ELF_INTERP_NON_RELOCATABLE */
434		addr = *last;
435
436	/*
437	 * Load all the necessary sections
438	 */
439	for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL;
440	     i < eh.e_phnum; i++, ph0++) {
441		switch (ph0->p_type) {
442		case PT_LOAD: {
443			u_long size;
444			int prot = 0;
445			int flags;
446
447			if (base_ph == NULL) {
448				/*
449				 * First encountered psection is always the
450				 * base psection.  Make sure it's aligned
451				 * properly (align down for topdown and align
452				 * upwards for not topdown).
453				 */
454				base_ph = ph0;
455				flags = VMCMD_BASE;
456				if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN)
457					addr = ELF_TRUNC(addr, ph0->p_align);
458				else
459					addr = ELF_ROUND(addr, ph0->p_align);
460			} else {
461				u_long limit = round_page(last_ph->p_vaddr
462				    + last_ph->p_memsz);
463				u_long base = trunc_page(ph0->p_vaddr);
464
465				/*
466				 * If there is a gap in between the psections,
467				 * map it as inaccessible so nothing else
468				 * mmap'ed will be placed there.
469				 */
470				if (limit != base) {
471					NEW_VMCMD2(vcset, vmcmd_map_zero,
472					    base - limit,
473					    limit - base_ph->p_vaddr, NULLVP,
474					    0, VM_PROT_NONE, VMCMD_RELATIVE);
475				}
476
477				addr = ph0->p_vaddr - base_ph->p_vaddr;
478				flags = VMCMD_RELATIVE;
479			}
480			last_ph = ph0;
481			ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
482			    &size, &prot, flags);
483			/*
484			 * If entry is within this psection then this
485			 * must contain the .text section.  *entryoff is
486			 * relative to the base psection.
487			 */
488			if (eh.e_entry >= ph0->p_vaddr &&
489			    eh.e_entry < (ph0->p_vaddr + size)) {
490				*entryoff = eh.e_entry - base_ph->p_vaddr;
491			}
492			addr += size;
493			break;
494		}
495
496		case PT_DYNAMIC:
497		case PT_PHDR:
498		case PT_NOTE:
499			break;
500
501		default:
502			break;
503		}
504	}
505
506	free(ph, M_TEMP);
507	/*
508	 * This value is ignored if TOPDOWN.
509	 */
510	*last = addr;
511	vrele(vp);
512	return 0;
513
514badunlock:
515	VOP_UNLOCK(vp, 0);
516
517bad:
518	if (ph != NULL)
519		free(ph, M_TEMP);
520#ifdef notyet /* XXX cgd 960926 */
521	(maybe) VOP_CLOSE it
522#endif
523	vrele(vp);
524	return error;
525}
526
527/*
528 * exec_elf_makecmds(): Prepare an Elf binary's exec package
529 *
530 * First, set of the various offsets/lengths in the exec package.
531 *
532 * Then, mark the text image busy (so it can be demand paged) or error
533 * out if this is not possible.  Finally, set up vmcmds for the
534 * text, data, bss, and stack segments.
535 */
536int
537ELFNAME2(exec,makecmds)(struct proc *p, struct exec_package *epp)
538{
539	Elf_Ehdr *eh = epp->ep_hdr;
540	Elf_Phdr *ph, *pp;
541	Elf_Addr phdr = 0, pos = 0;
542	int error, i, nload;
543	char *interp = NULL;
544	u_long phsize;
545
546	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
547		return ENOEXEC;
548
549	/*
550	 * XXX allow for executing shared objects. It seems silly
551	 * but other ELF-based systems allow it as well.
552	 */
553	if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
554	    ELFNAME(check_header)(eh, ET_DYN) != 0)
555		return ENOEXEC;
556
557	if (eh->e_phnum > MAXPHNUM)
558		return ENOEXEC;
559
560	error = vn_marktext(epp->ep_vp);
561	if (error)
562		return (error);
563
564	/*
565	 * Allocate space to hold all the program headers, and read them
566	 * from the file
567	 */
568	phsize = eh->e_phnum * sizeof(Elf_Phdr);
569	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
570
571	if ((error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) !=
572	    0)
573		goto bad;
574
575	epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
576	epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
577
578	MALLOC(interp, char *, MAXPATHLEN, M_TEMP, M_WAITOK);
579	interp[0] = '\0';
580
581	for (i = 0; i < eh->e_phnum; i++) {
582		pp = &ph[i];
583		if (pp->p_type == PT_INTERP) {
584			if (pp->p_filesz >= MAXPATHLEN)
585				goto bad;
586			if ((error = exec_read_from(p, epp->ep_vp,
587			    pp->p_offset, interp, pp->p_filesz)) != 0)
588				goto bad;
589			break;
590		}
591	}
592
593	/*
594	 * On the same architecture, we may be emulating different systems.
595	 * See which one will accept this executable. This currently only
596	 * applies to SVR4, and IBCS2 on the i386 and Linux on the i386
597	 * and the Alpha.
598	 *
599	 * Probe functions would normally see if the interpreter (if any)
600	 * exists. Emulation packages may possibly replace the interpreter in
601	 * interp[] with a changed path (/emul/xxx/<path>).
602	 */
603	if (!epp->ep_esch->u.elf_probe_func) {
604		pos = ELFDEFNNAME(NO_ADDR);
605	} else {
606		vaddr_t startp = 0;
607
608		error = (*epp->ep_esch->u.elf_probe_func)(p, epp, eh, interp,
609							  &startp);
610		pos = (Elf_Addr)startp;
611		if (error)
612			goto bad;
613	}
614
615	/*
616	 * Load all the necessary sections
617	 */
618	for (i = nload = 0; i < eh->e_phnum; i++) {
619		Elf_Addr  addr = ELFDEFNNAME(NO_ADDR);
620		u_long size = 0;
621		int prot = 0;
622
623		pp = &ph[i];
624
625		switch (ph[i].p_type) {
626		case PT_LOAD:
627			/*
628			 * XXX
629			 * Can handle only 2 sections: text and data
630			 */
631			if (nload++ == 2)
632				goto bad;
633			ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
634			    &ph[i], &addr, &size, &prot, VMCMD_FIXED);
635
636			/*
637			 * Decide whether it's text or data by looking
638			 * at the entry point.
639			 */
640			if (eh->e_entry >= addr &&
641			    eh->e_entry < (addr + size)) {
642				epp->ep_taddr = addr;
643				epp->ep_tsize = size;
644				if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
645					epp->ep_daddr = addr;
646					epp->ep_dsize = size;
647				}
648			} else {
649				epp->ep_daddr = addr;
650				epp->ep_dsize = size;
651			}
652			break;
653
654		case PT_SHLIB:
655			/* SCO has these sections. */
656		case PT_INTERP:
657			/* Already did this one. */
658		case PT_DYNAMIC:
659		case PT_NOTE:
660			break;
661
662		case PT_PHDR:
663			/* Note address of program headers (in text segment) */
664			phdr = pp->p_vaddr;
665			break;
666
667		default:
668			/*
669			 * Not fatal; we don't need to understand everything.
670			 */
671			break;
672		}
673	}
674
675	/*
676	 * Check if we found a dynamically linked binary and arrange to load
677	 * its interpreter
678	 */
679	if (interp[0]) {
680		struct elf_args *ap;
681		int i = epp->ep_vmcmds.evs_used;
682		u_long interp_offset;
683
684		MALLOC(ap, struct elf_args *, sizeof(struct elf_args),
685		    M_TEMP, M_WAITOK);
686		if ((error = ELFNAME(load_file)(p, epp, interp,
687		    &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) {
688			FREE(ap, M_TEMP);
689			goto bad;
690		}
691		ap->arg_interp = epp->ep_vmcmds.evs_cmds[i].ev_addr;
692		epp->ep_entry = ap->arg_interp + interp_offset;
693		ap->arg_phaddr = phdr;
694
695		ap->arg_phentsize = eh->e_phentsize;
696		ap->arg_phnum = eh->e_phnum;
697		ap->arg_entry = eh->e_entry;
698
699		epp->ep_emul_arg = ap;
700	} else
701		epp->ep_entry = eh->e_entry;
702
703#ifdef ELF_MAP_PAGE_ZERO
704	/* Dell SVR4 maps page zero, yeuch! */
705	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
706	    epp->ep_vp, 0, VM_PROT_READ);
707#endif
708	FREE(interp, M_TEMP);
709	free(ph, M_TEMP);
710	return exec_elf_setup_stack(p, epp);
711
712bad:
713	if (interp)
714		FREE(interp, M_TEMP);
715	free(ph, M_TEMP);
716	kill_vmcmds(&epp->ep_vmcmds);
717	return ENOEXEC;
718}
719
720int
721ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp,
722    Elf_Ehdr *eh)
723{
724	size_t i;
725	Elf_Phdr *ph;
726	size_t phsize;
727	int error;
728
729	if (eh->e_phnum > MAXPHNUM)
730		return ENOEXEC;
731
732	phsize = eh->e_phnum * sizeof(Elf_Phdr);
733	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
734	error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize);
735	if (error)
736		goto out;
737
738	for (i = 0; i < eh->e_phnum; i++) {
739		Elf_Phdr *ephp = &ph[i];
740		Elf_Nhdr *np;
741
742		if (ephp->p_type != PT_NOTE ||
743		    ephp->p_filesz > 1024 ||
744		    ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
745			continue;
746
747		np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
748		error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np,
749		    ephp->p_filesz);
750		if (error)
751			goto next;
752
753		if (np->n_type != ELF_NOTE_TYPE_NETBSD_TAG ||
754		    np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
755		    np->n_descsz != ELF_NOTE_NETBSD_DESCSZ ||
756		    memcmp((caddr_t)(np + 1), ELF_NOTE_NETBSD_NAME,
757		    ELF_NOTE_NETBSD_NAMESZ))
758			goto next;
759
760		error = 0;
761		free(np, M_TEMP);
762		goto out;
763
764	next:
765		free(np, M_TEMP);
766		continue;
767	}
768
769	error = ENOEXEC;
770out:
771	free(ph, M_TEMP);
772	return (error);
773}
774
775int
776ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp,
777    void *eh, char *itp, vaddr_t *pos)
778{
779	int error;
780
781	if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
782		return error;
783	*pos = ELFDEFNNAME(NO_ADDR);
784	return 0;
785}
786