xref: /netbsd-src/sys/kern/exec_elf32.c (revision da5f4674a3fc214be3572d358b66af40ab9401e7)
1 /*	$NetBSD: exec_elf32.c,v 1.94 2003/08/08 18:53:13 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 1.94 2003/08/08 18:53:13 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 
89 extern const struct emul emul_netbsd;
90 
91 int	ELFNAME(load_file)(struct proc *, struct exec_package *, char *,
92 	    struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *);
93 void	ELFNAME(load_psection)(struct exec_vmcmd_set *, struct vnode *,
94 	    const Elf_Phdr *, Elf_Addr *, u_long *, int *, int);
95 
96 int ELFNAME2(netbsd,signature)(struct proc *, struct exec_package *,
97     Elf_Ehdr *);
98 int ELFNAME2(netbsd,probe)(struct proc *, struct exec_package *,
99     void *, char *, vaddr_t *);
100 
101 /* round up and down to page boundaries. */
102 #define	ELF_ROUND(a, b)		(((a) + (b) - 1) & ~((b) - 1))
103 #define	ELF_TRUNC(a, b)		((a) & ~((b) - 1))
104 
105 #define MAXPHNUM	50
106 
107 /*
108  * Copy arguments onto the stack in the normal way, but add some
109  * extra information in case of dynamic binding.
110  */
111 int
112 ELFNAME(copyargs)(struct proc *p, struct exec_package *pack,
113     struct ps_strings *arginfo, char **stackp, void *argp)
114 {
115 	size_t len;
116 	AuxInfo ai[ELF_AUX_ENTRIES], *a;
117 	struct elf_args *ap;
118 	int error;
119 
120 	if ((error = copyargs(p, pack, arginfo, stackp, argp)) != 0)
121 		return error;
122 
123 	a = ai;
124 
125 	/*
126 	 * Push extra arguments on the stack needed by dynamically
127 	 * linked binaries
128 	 */
129 	if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
130 		struct vattr *vap = pack->ep_vap;
131 
132 		a->a_type = AT_PHDR;
133 		a->a_v = ap->arg_phaddr;
134 		a++;
135 
136 		a->a_type = AT_PHENT;
137 		a->a_v = ap->arg_phentsize;
138 		a++;
139 
140 		a->a_type = AT_PHNUM;
141 		a->a_v = ap->arg_phnum;
142 		a++;
143 
144 		a->a_type = AT_PAGESZ;
145 		a->a_v = PAGE_SIZE;
146 		a++;
147 
148 		a->a_type = AT_BASE;
149 		a->a_v = ap->arg_interp;
150 		a++;
151 
152 		a->a_type = AT_FLAGS;
153 		a->a_v = 0;
154 		a++;
155 
156 		a->a_type = AT_ENTRY;
157 		a->a_v = ap->arg_entry;
158 		a++;
159 
160 		a->a_type = AT_EUID;
161 		if (vap->va_mode & S_ISUID)
162 			a->a_v = vap->va_uid;
163 		else
164 			a->a_v = p->p_ucred->cr_uid;
165 		a++;
166 
167 		a->a_type = AT_RUID;
168 		a->a_v = p->p_cred->p_ruid;
169 		a++;
170 
171 		a->a_type = AT_EGID;
172 		if (vap->va_mode & S_ISGID)
173 			a->a_v = vap->va_gid;
174 		else
175 			a->a_v = p->p_ucred->cr_gid;
176 		a++;
177 
178 		a->a_type = AT_RGID;
179 		a->a_v = p->p_cred->p_rgid;
180 		a++;
181 
182 		free(ap, M_TEMP);
183 		pack->ep_emul_arg = NULL;
184 	}
185 
186 	a->a_type = AT_NULL;
187 	a->a_v = 0;
188 	a++;
189 
190 	len = (a - ai) * sizeof(AuxInfo);
191 	if ((error = copyout(ai, *stackp, len)) != 0)
192 		return error;
193 	*stackp += len;
194 
195 	return 0;
196 }
197 
198 /*
199  * elf_check_header():
200  *
201  * Check header for validity; return 0 of ok ENOEXEC if error
202  */
203 int
204 ELFNAME(check_header)(Elf_Ehdr *eh, int type)
205 {
206 
207 	if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
208 	    eh->e_ident[EI_CLASS] != ELFCLASS)
209 		return (ENOEXEC);
210 
211 	switch (eh->e_machine) {
212 
213 	ELFDEFNNAME(MACHDEP_ID_CASES)
214 
215 	default:
216 		return (ENOEXEC);
217 	}
218 
219 	if (ELF_EHDR_FLAGS_OK(eh) == 0)
220 		return (ENOEXEC);
221 
222 	if (eh->e_type != type)
223 		return (ENOEXEC);
224 
225 	if (eh->e_shnum > 512 ||
226 	    eh->e_phnum > 128)
227 		return (ENOEXEC);
228 
229 	return (0);
230 }
231 
232 /*
233  * elf_load_psection():
234  *
235  * Load a psection at the appropriate address
236  */
237 void
238 ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp,
239     const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags)
240 {
241 	u_long msize, psize, rm, rf;
242 	long diff, offset;
243 
244 	/*
245 	 * If the user specified an address, then we load there.
246 	 */
247 	if (*addr == ELFDEFNNAME(NO_ADDR))
248 		*addr = ph->p_vaddr;
249 
250 	if (ph->p_align > 1) {
251 		/*
252 		 * Make sure we are virtually aligned as we are supposed to be.
253 		 */
254 		diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
255 		KASSERT(*addr - diff == ELF_TRUNC(*addr, ph->p_align));
256 		/*
257 		 * But make sure to not map any pages before the start of the
258 		 * psection by limiting the difference to within a page.
259 		 */
260 		diff &= PAGE_MASK;
261 	} else
262 		diff = 0;
263 
264 	*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
265 	*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
266 	*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
267 
268 	/*
269 	 * Adjust everything so it all starts on a page boundary.
270 	 */
271 	*addr -= diff;
272 	offset = ph->p_offset - diff;
273 	*size = ph->p_filesz + diff;
274 	msize = ph->p_memsz + diff;
275 
276 	if (ph->p_align >= PAGE_SIZE) {
277 		if ((ph->p_flags & PF_W) != 0) {
278 			/*
279 			 * Because the pagedvn pager can't handle zero fill
280 			 * of the last data page if it's not page aligned we
281 			 * map the last page readvn.
282 			 */
283 			psize = trunc_page(*size);
284 		} else {
285 			psize = round_page(*size);
286 		}
287 	} else {
288 		psize = *size;
289 	}
290 
291 	if (psize > 0) {
292 		NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ?
293 		    vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp,
294 		    offset, *prot, flags);
295 		flags &= VMCMD_RELATIVE;
296 	}
297 	if (psize < *size) {
298 		NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
299 		    *addr + psize, vp, offset + psize, *prot, flags);
300 	}
301 
302 	/*
303 	 * Check if we need to extend the size of the segment (does
304 	 * bss extend page the next page boundary)?
305 	 */
306 	rm = round_page(*addr + msize);
307 	rf = round_page(*addr + *size);
308 
309 	if (rm != rf) {
310 		NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
311 		    0, *prot, flags & VMCMD_RELATIVE);
312 		*size = msize;
313 	}
314 }
315 
316 /*
317  * elf_load_file():
318  *
319  * Load a file (interpreter/library) pointed to by path
320  * [stolen from coff_load_shlib()]. Made slightly generic
321  * so it might be used externally.
322  */
323 int
324 ELFNAME(load_file)(struct proc *p, struct exec_package *epp, char *path,
325     struct exec_vmcmd_set *vcset, u_long *entryoff, struct elf_args *ap,
326     Elf_Addr *last)
327 {
328 	int error, i;
329 	struct nameidata nd;
330 	struct vnode *vp;
331 	struct vattr attr;
332 	Elf_Ehdr eh;
333 	Elf_Phdr *ph = NULL;
334 	const Elf_Phdr *ph0;
335 	const Elf_Phdr *base_ph;
336 	const Elf_Phdr *last_ph;
337 	u_long phsize;
338 	Elf_Addr addr = *last;
339 
340 	/*
341 	 * 1. open file
342 	 * 2. read filehdr
343 	 * 3. map text, data, and bss out of it using VM_*
344 	 */
345 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
346 	if ((error = namei(&nd)) != 0)
347 		return error;
348 	vp = nd.ni_vp;
349 
350 	/*
351 	 * Similarly, if it's not marked as executable, or it's not a regular
352 	 * file, we don't allow it to be used.
353 	 */
354 	if (vp->v_type != VREG) {
355 		error = EACCES;
356 		goto badunlock;
357 	}
358 	if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
359 		goto badunlock;
360 
361 	/* get attributes */
362 	if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
363 		goto badunlock;
364 
365 	/*
366 	 * Check mount point.  Though we're not trying to exec this binary,
367 	 * we will be executing code from it, so if the mount point
368 	 * disallows execution or set-id-ness, we punt or kill the set-id.
369 	 */
370 	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
371 		error = EACCES;
372 		goto badunlock;
373 	}
374 	if (vp->v_mount->mnt_flag & MNT_NOSUID)
375 		epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
376 
377 #ifdef notyet /* XXX cgd 960926 */
378 	XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
379 #endif
380 
381 	error = vn_marktext(vp);
382 	if (error)
383 		goto badunlock;
384 
385 	VOP_UNLOCK(vp, 0);
386 
387 	if ((error = exec_read_from(p, vp, 0, &eh, sizeof(eh))) != 0)
388 		goto bad;
389 
390 	if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
391 		goto bad;
392 
393 	if (eh.e_phnum > MAXPHNUM)
394 		goto bad;
395 
396 	phsize = eh.e_phnum * sizeof(Elf_Phdr);
397 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
398 
399 	if ((error = exec_read_from(p, vp, eh.e_phoff, ph, phsize)) != 0)
400 		goto bad;
401 
402 	/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
403 #ifndef ELF_INTERP_NON_RELOCATABLE
404 	/*
405 	 * If no position to load the interpreter was set by a probe
406 	 * function, pick the same address that a non-fixed mmap(0, ..)
407 	 * would (i.e. something safely out of the way).
408 	 */
409 	if (*last == ELFDEFNNAME(NO_ADDR)) {
410 		u_long limit = 0;
411 		/*
412 		 * Find the start and ending addresses of the psections to
413 		 * be loaded.  This will give us the size.
414 		 */
415 		for (i = 0, ph0 = ph, base_ph = NULL; i < eh.e_phnum;
416 		     i++, ph0++) {
417 			if (ph0->p_type == PT_LOAD) {
418 				u_long psize = ph0->p_vaddr + ph0->p_memsz;
419 				if (base_ph == NULL)
420 					base_ph = ph0;
421 				if (psize > limit)
422 					limit = psize;
423 			}
424 		}
425 
426 		/*
427 		 * Now compute the size and load address.
428 		 */
429 		addr = VM_DEFAULT_ADDRESS(epp->ep_daddr,
430 		    round_page(limit) - trunc_page(base_ph->p_vaddr));
431 	} else
432 #endif	/* !ELF_INTERP_NON_RELOCATABLE */
433 		addr = *last;
434 
435 	/*
436 	 * Load all the necessary sections
437 	 */
438 	for (i = 0, ph0 = ph, base_ph = NULL, last_ph = NULL;
439 	     i < eh.e_phnum; i++, ph0++) {
440 		switch (ph0->p_type) {
441 		case PT_LOAD: {
442 			u_long size;
443 			int prot = 0;
444 			int flags;
445 
446 			if (base_ph == NULL) {
447 				/*
448 				 * First encountered psection is always the
449 				 * base psection.  Make sure it's aligned
450 				 * properly (align down for topdown and align
451 				 * upwards for not topdown).
452 				 */
453 				base_ph = ph0;
454 				flags = VMCMD_BASE;
455 				if (p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN)
456 					addr = ELF_TRUNC(addr, ph0->p_align);
457 				else
458 					addr = ELF_ROUND(addr, ph0->p_align);
459 			} else {
460 				u_long limit = round_page(last_ph->p_vaddr
461 				    + last_ph->p_memsz);
462 				u_long base = trunc_page(ph0->p_vaddr);
463 
464 				/*
465 				 * If there is a gap in between the psections,
466 				 * map it as inaccessible so nothing else
467 				 * mmap'ed will be placed there.
468 				 */
469 				if (limit != base) {
470 					NEW_VMCMD2(vcset, vmcmd_map_zero,
471 					    base - limit,
472 					    limit - base_ph->p_vaddr, NULLVP,
473 					    0, VM_PROT_NONE, VMCMD_RELATIVE);
474 				}
475 
476 				addr = ph0->p_vaddr - base_ph->p_vaddr;
477 				flags = VMCMD_RELATIVE;
478 			}
479 			last_ph = ph0;
480 			ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
481 			    &size, &prot, flags);
482 			/*
483 			 * If entry is within this psection then this
484 			 * must contain the .text section.  *entryoff is
485 			 * relative to the base psection.
486 			 */
487 			if (eh.e_entry >= ph0->p_vaddr &&
488 			    eh.e_entry < (ph0->p_vaddr + size)) {
489 				*entryoff = eh.e_entry - base_ph->p_vaddr;
490 			}
491 			addr += size;
492 			break;
493 		}
494 
495 		case PT_DYNAMIC:
496 		case PT_PHDR:
497 		case PT_NOTE:
498 			break;
499 
500 		default:
501 			break;
502 		}
503 	}
504 
505 	free(ph, M_TEMP);
506 	/*
507 	 * This value is ignored if TOPDOWN.
508 	 */
509 	*last = addr;
510 	vrele(vp);
511 	return 0;
512 
513 badunlock:
514 	VOP_UNLOCK(vp, 0);
515 
516 bad:
517 	if (ph != NULL)
518 		free(ph, M_TEMP);
519 #ifdef notyet /* XXX cgd 960926 */
520 	(maybe) VOP_CLOSE it
521 #endif
522 	vrele(vp);
523 	return error;
524 }
525 
526 /*
527  * exec_elf_makecmds(): Prepare an Elf binary's exec package
528  *
529  * First, set of the various offsets/lengths in the exec package.
530  *
531  * Then, mark the text image busy (so it can be demand paged) or error
532  * out if this is not possible.  Finally, set up vmcmds for the
533  * text, data, bss, and stack segments.
534  */
535 int
536 ELFNAME2(exec,makecmds)(struct proc *p, struct exec_package *epp)
537 {
538 	Elf_Ehdr *eh = epp->ep_hdr;
539 	Elf_Phdr *ph, *pp;
540 	Elf_Addr phdr = 0, pos = 0;
541 	int error, i, nload;
542 	char *interp = NULL;
543 	u_long phsize;
544 
545 	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
546 		return ENOEXEC;
547 
548 	/*
549 	 * XXX allow for executing shared objects. It seems silly
550 	 * but other ELF-based systems allow it as well.
551 	 */
552 	if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
553 	    ELFNAME(check_header)(eh, ET_DYN) != 0)
554 		return ENOEXEC;
555 
556 	if (eh->e_phnum > MAXPHNUM)
557 		return ENOEXEC;
558 
559 	error = vn_marktext(epp->ep_vp);
560 	if (error)
561 		return (error);
562 
563 	/*
564 	 * Allocate space to hold all the program headers, and read them
565 	 * from the file
566 	 */
567 	phsize = eh->e_phnum * sizeof(Elf_Phdr);
568 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
569 
570 	if ((error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) !=
571 	    0)
572 		goto bad;
573 
574 	epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
575 	epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
576 
577 	MALLOC(interp, char *, MAXPATHLEN, M_TEMP, M_WAITOK);
578 	interp[0] = '\0';
579 
580 	for (i = 0; i < eh->e_phnum; i++) {
581 		pp = &ph[i];
582 		if (pp->p_type == PT_INTERP) {
583 			if (pp->p_filesz >= MAXPATHLEN)
584 				goto bad;
585 			if ((error = exec_read_from(p, epp->ep_vp,
586 			    pp->p_offset, interp, pp->p_filesz)) != 0)
587 				goto bad;
588 			break;
589 		}
590 	}
591 
592 	/*
593 	 * On the same architecture, we may be emulating different systems.
594 	 * See which one will accept this executable. This currently only
595 	 * applies to SVR4, and IBCS2 on the i386 and Linux on the i386
596 	 * and the Alpha.
597 	 *
598 	 * Probe functions would normally see if the interpreter (if any)
599 	 * exists. Emulation packages may possibly replace the interpreter in
600 	 * interp[] with a changed path (/emul/xxx/<path>).
601 	 */
602 	if (!epp->ep_esch->u.elf_probe_func) {
603 		pos = ELFDEFNNAME(NO_ADDR);
604 	} else {
605 		vaddr_t startp = 0;
606 
607 		error = (*epp->ep_esch->u.elf_probe_func)(p, epp, eh, interp,
608 							  &startp);
609 		pos = (Elf_Addr)startp;
610 		if (error)
611 			goto bad;
612 	}
613 
614 	/*
615 	 * Load all the necessary sections
616 	 */
617 	for (i = nload = 0; i < eh->e_phnum; i++) {
618 		Elf_Addr  addr = ELFDEFNNAME(NO_ADDR);
619 		u_long size = 0;
620 		int prot = 0;
621 
622 		pp = &ph[i];
623 
624 		switch (ph[i].p_type) {
625 		case PT_LOAD:
626 			/*
627 			 * XXX
628 			 * Can handle only 2 sections: text and data
629 			 */
630 			if (nload++ == 2)
631 				goto bad;
632 			ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
633 			    &ph[i], &addr, &size, &prot, VMCMD_FIXED);
634 
635 			/*
636 			 * Decide whether it's text or data by looking
637 			 * at the entry point.
638 			 */
639 			if (eh->e_entry >= addr &&
640 			    eh->e_entry < (addr + size)) {
641 				epp->ep_taddr = addr;
642 				epp->ep_tsize = size;
643 				if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
644 					epp->ep_daddr = addr;
645 					epp->ep_dsize = size;
646 				}
647 			} else {
648 				epp->ep_daddr = addr;
649 				epp->ep_dsize = size;
650 			}
651 			break;
652 
653 		case PT_SHLIB:
654 			/* SCO has these sections. */
655 		case PT_INTERP:
656 			/* Already did this one. */
657 		case PT_DYNAMIC:
658 		case PT_NOTE:
659 			break;
660 
661 		case PT_PHDR:
662 			/* Note address of program headers (in text segment) */
663 			phdr = pp->p_vaddr;
664 			break;
665 
666 		default:
667 			/*
668 			 * Not fatal; we don't need to understand everything.
669 			 */
670 			break;
671 		}
672 	}
673 
674 	/*
675 	 * Check if we found a dynamically linked binary and arrange to load
676 	 * its interpreter
677 	 */
678 	if (interp[0]) {
679 		struct elf_args *ap;
680 		int i = epp->ep_vmcmds.evs_used;
681 		u_long interp_offset;
682 
683 		MALLOC(ap, struct elf_args *, sizeof(struct elf_args),
684 		    M_TEMP, M_WAITOK);
685 		if ((error = ELFNAME(load_file)(p, epp, interp,
686 		    &epp->ep_vmcmds, &interp_offset, ap, &pos)) != 0) {
687 			FREE(ap, M_TEMP);
688 			goto bad;
689 		}
690 		ap->arg_interp = epp->ep_vmcmds.evs_cmds[i].ev_addr;
691 		epp->ep_entry = ap->arg_interp + interp_offset;
692 		ap->arg_phaddr = phdr;
693 
694 		ap->arg_phentsize = eh->e_phentsize;
695 		ap->arg_phnum = eh->e_phnum;
696 		ap->arg_entry = eh->e_entry;
697 
698 		epp->ep_emul_arg = ap;
699 	} else
700 		epp->ep_entry = eh->e_entry;
701 
702 #ifdef ELF_MAP_PAGE_ZERO
703 	/* Dell SVR4 maps page zero, yeuch! */
704 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
705 	    epp->ep_vp, 0, VM_PROT_READ);
706 #endif
707 	FREE(interp, M_TEMP);
708 	free(ph, M_TEMP);
709 	return (*epp->ep_esch->es_setup_stack)(p, epp);
710 
711 bad:
712 	if (interp)
713 		FREE(interp, M_TEMP);
714 	free(ph, M_TEMP);
715 	kill_vmcmds(&epp->ep_vmcmds);
716 	return ENOEXEC;
717 }
718 
719 int
720 ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp,
721     Elf_Ehdr *eh)
722 {
723 	size_t i;
724 	Elf_Phdr *ph;
725 	size_t phsize;
726 	int error;
727 
728 	if (eh->e_phnum > MAXPHNUM)
729 		return ENOEXEC;
730 
731 	phsize = eh->e_phnum * sizeof(Elf_Phdr);
732 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
733 	error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize);
734 	if (error)
735 		goto out;
736 
737 	for (i = 0; i < eh->e_phnum; i++) {
738 		Elf_Phdr *ephp = &ph[i];
739 		Elf_Nhdr *np;
740 
741 		if (ephp->p_type != PT_NOTE ||
742 		    ephp->p_filesz > 1024 ||
743 		    ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
744 			continue;
745 
746 		np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
747 		error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np,
748 		    ephp->p_filesz);
749 		if (error)
750 			goto next;
751 
752 		if (np->n_type != ELF_NOTE_TYPE_NETBSD_TAG ||
753 		    np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
754 		    np->n_descsz != ELF_NOTE_NETBSD_DESCSZ ||
755 		    memcmp((caddr_t)(np + 1), ELF_NOTE_NETBSD_NAME,
756 		    ELF_NOTE_NETBSD_NAMESZ))
757 			goto next;
758 
759 		error = 0;
760 		free(np, M_TEMP);
761 		goto out;
762 
763 	next:
764 		free(np, M_TEMP);
765 		continue;
766 	}
767 
768 	error = ENOEXEC;
769 out:
770 	free(ph, M_TEMP);
771 	return (error);
772 }
773 
774 int
775 ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp,
776     void *eh, char *itp, vaddr_t *pos)
777 {
778 	int error;
779 
780 	if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
781 		return error;
782 	*pos = ELFDEFNNAME(NO_ADDR);
783 	return 0;
784 }
785