readelf.c revision 284194
1/*
2 * Copyright (c) Christos Zoulas 2003.
3 * All Rights Reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice immediately at the beginning of the file, without modification,
10 *    this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
19 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27#include "file.h"
28
29#ifndef lint
30FILE_RCSID("@(#)$File: readelf.c,v 1.117 2014/12/16 23:29:42 christos Exp $")
31#endif
32
33#ifdef BUILTIN_ELF
34#include <string.h>
35#include <ctype.h>
36#include <stdlib.h>
37#ifdef HAVE_UNISTD_H
38#include <unistd.h>
39#endif
40
41#include "readelf.h"
42#include "magic.h"
43
44#ifdef	ELFCORE
45private int dophn_core(struct magic_set *, int, int, int, off_t, int, size_t,
46    off_t, int *, uint16_t *);
47#endif
48private int dophn_exec(struct magic_set *, int, int, int, off_t, int, size_t,
49    off_t, int, int *, uint16_t *);
50private int doshn(struct magic_set *, int, int, int, off_t, int, size_t,
51    off_t, int, int, int *, uint16_t *);
52private size_t donote(struct magic_set *, void *, size_t, size_t, int,
53    int, size_t, int *, uint16_t *);
54
55#define	ELF_ALIGN(a)	((((a) + align - 1) / align) * align)
56
57#define isquote(c) (strchr("'\"`", (c)) != NULL)
58
59private uint16_t getu16(int, uint16_t);
60private uint32_t getu32(int, uint32_t);
61private uint64_t getu64(int, uint64_t);
62
63#define MAX_PHNUM	128
64#define	MAX_SHNUM	32768
65#define SIZE_UNKNOWN	((off_t)-1)
66
67private int
68toomany(struct magic_set *ms, const char *name, uint16_t num)
69{
70	if (file_printf(ms, ", too many %s (%u)", name, num
71	    ) == -1)
72		return -1;
73	return 0;
74}
75
76private uint16_t
77getu16(int swap, uint16_t value)
78{
79	union {
80		uint16_t ui;
81		char c[2];
82	} retval, tmpval;
83
84	if (swap) {
85		tmpval.ui = value;
86
87		retval.c[0] = tmpval.c[1];
88		retval.c[1] = tmpval.c[0];
89
90		return retval.ui;
91	} else
92		return value;
93}
94
95private uint32_t
96getu32(int swap, uint32_t value)
97{
98	union {
99		uint32_t ui;
100		char c[4];
101	} retval, tmpval;
102
103	if (swap) {
104		tmpval.ui = value;
105
106		retval.c[0] = tmpval.c[3];
107		retval.c[1] = tmpval.c[2];
108		retval.c[2] = tmpval.c[1];
109		retval.c[3] = tmpval.c[0];
110
111		return retval.ui;
112	} else
113		return value;
114}
115
116private uint64_t
117getu64(int swap, uint64_t value)
118{
119	union {
120		uint64_t ui;
121		char c[8];
122	} retval, tmpval;
123
124	if (swap) {
125		tmpval.ui = value;
126
127		retval.c[0] = tmpval.c[7];
128		retval.c[1] = tmpval.c[6];
129		retval.c[2] = tmpval.c[5];
130		retval.c[3] = tmpval.c[4];
131		retval.c[4] = tmpval.c[3];
132		retval.c[5] = tmpval.c[2];
133		retval.c[6] = tmpval.c[1];
134		retval.c[7] = tmpval.c[0];
135
136		return retval.ui;
137	} else
138		return value;
139}
140
141#define elf_getu16(swap, value) getu16(swap, value)
142#define elf_getu32(swap, value) getu32(swap, value)
143#define elf_getu64(swap, value) getu64(swap, value)
144
145#define xsh_addr	(clazz == ELFCLASS32			\
146			 ? (void *)&sh32			\
147			 : (void *)&sh64)
148#define xsh_sizeof	(clazz == ELFCLASS32			\
149			 ? sizeof(sh32)				\
150			 : sizeof(sh64))
151#define xsh_size	(size_t)(clazz == ELFCLASS32		\
152			 ? elf_getu32(swap, sh32.sh_size)	\
153			 : elf_getu64(swap, sh64.sh_size))
154#define xsh_offset	(off_t)(clazz == ELFCLASS32		\
155			 ? elf_getu32(swap, sh32.sh_offset)	\
156			 : elf_getu64(swap, sh64.sh_offset))
157#define xsh_type	(clazz == ELFCLASS32			\
158			 ? elf_getu32(swap, sh32.sh_type)	\
159			 : elf_getu32(swap, sh64.sh_type))
160#define xsh_name    	(clazz == ELFCLASS32			\
161			 ? elf_getu32(swap, sh32.sh_name)	\
162			 : elf_getu32(swap, sh64.sh_name))
163#define xph_addr	(clazz == ELFCLASS32			\
164			 ? (void *) &ph32			\
165			 : (void *) &ph64)
166#define xph_sizeof	(clazz == ELFCLASS32			\
167			 ? sizeof(ph32)				\
168			 : sizeof(ph64))
169#define xph_type	(clazz == ELFCLASS32			\
170			 ? elf_getu32(swap, ph32.p_type)	\
171			 : elf_getu32(swap, ph64.p_type))
172#define xph_offset	(off_t)(clazz == ELFCLASS32		\
173			 ? elf_getu32(swap, ph32.p_offset)	\
174			 : elf_getu64(swap, ph64.p_offset))
175#define xph_align	(size_t)((clazz == ELFCLASS32		\
176			 ? (off_t) (ph32.p_align ? 		\
177			    elf_getu32(swap, ph32.p_align) : 4) \
178			 : (off_t) (ph64.p_align ?		\
179			    elf_getu64(swap, ph64.p_align) : 4)))
180#define xph_filesz	(size_t)((clazz == ELFCLASS32		\
181			 ? elf_getu32(swap, ph32.p_filesz)	\
182			 : elf_getu64(swap, ph64.p_filesz)))
183#define xnh_addr	(clazz == ELFCLASS32			\
184			 ? (void *)&nh32			\
185			 : (void *)&nh64)
186#define xph_memsz	(size_t)((clazz == ELFCLASS32		\
187			 ? elf_getu32(swap, ph32.p_memsz)	\
188			 : elf_getu64(swap, ph64.p_memsz)))
189#define xnh_sizeof	(clazz == ELFCLASS32			\
190			 ? sizeof nh32				\
191			 : sizeof nh64)
192#define xnh_type	(clazz == ELFCLASS32			\
193			 ? elf_getu32(swap, nh32.n_type)	\
194			 : elf_getu32(swap, nh64.n_type))
195#define xnh_namesz	(clazz == ELFCLASS32			\
196			 ? elf_getu32(swap, nh32.n_namesz)	\
197			 : elf_getu32(swap, nh64.n_namesz))
198#define xnh_descsz	(clazz == ELFCLASS32			\
199			 ? elf_getu32(swap, nh32.n_descsz)	\
200			 : elf_getu32(swap, nh64.n_descsz))
201#define prpsoffsets(i)	(clazz == ELFCLASS32			\
202			 ? prpsoffsets32[i]			\
203			 : prpsoffsets64[i])
204#define xcap_addr	(clazz == ELFCLASS32			\
205			 ? (void *)&cap32			\
206			 : (void *)&cap64)
207#define xcap_sizeof	(clazz == ELFCLASS32			\
208			 ? sizeof cap32				\
209			 : sizeof cap64)
210#define xcap_tag	(clazz == ELFCLASS32			\
211			 ? elf_getu32(swap, cap32.c_tag)	\
212			 : elf_getu64(swap, cap64.c_tag))
213#define xcap_val	(clazz == ELFCLASS32			\
214			 ? elf_getu32(swap, cap32.c_un.c_val)	\
215			 : elf_getu64(swap, cap64.c_un.c_val))
216
217#ifdef ELFCORE
218/*
219 * Try larger offsets first to avoid false matches
220 * from earlier data that happen to look like strings.
221 */
222static const size_t	prpsoffsets32[] = {
223#ifdef USE_NT_PSINFO
224	104,		/* SunOS 5.x (command line) */
225	88,		/* SunOS 5.x (short name) */
226#endif /* USE_NT_PSINFO */
227
228	100,		/* SunOS 5.x (command line) */
229	84,		/* SunOS 5.x (short name) */
230
231	44,		/* Linux (command line) */
232	28,		/* Linux 2.0.36 (short name) */
233
234	8,		/* FreeBSD */
235};
236
237static const size_t	prpsoffsets64[] = {
238#ifdef USE_NT_PSINFO
239	152,		/* SunOS 5.x (command line) */
240	136,		/* SunOS 5.x (short name) */
241#endif /* USE_NT_PSINFO */
242
243	136,		/* SunOS 5.x, 64-bit (command line) */
244	120,		/* SunOS 5.x, 64-bit (short name) */
245
246	56,		/* Linux (command line) */
247	40,             /* Linux (tested on core from 2.4.x, short name) */
248
249	16,		/* FreeBSD, 64-bit */
250};
251
252#define	NOFFSETS32	(sizeof prpsoffsets32 / sizeof prpsoffsets32[0])
253#define NOFFSETS64	(sizeof prpsoffsets64 / sizeof prpsoffsets64[0])
254
255#define NOFFSETS	(clazz == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
256
257/*
258 * Look through the program headers of an executable image, searching
259 * for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE" or
260 * "FreeBSD"; if one is found, try looking in various places in its
261 * contents for a 16-character string containing only printable
262 * characters - if found, that string should be the name of the program
263 * that dropped core.  Note: right after that 16-character string is,
264 * at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
265 * Linux, a longer string (80 characters, in 5.x, probably other
266 * SVR4-flavored systems, and Linux) containing the start of the
267 * command line for that program.
268 *
269 * SunOS 5.x core files contain two PT_NOTE sections, with the types
270 * NT_PRPSINFO (old) and NT_PSINFO (new).  These structs contain the
271 * same info about the command name and command line, so it probably
272 * isn't worthwhile to look for NT_PSINFO, but the offsets are provided
273 * above (see USE_NT_PSINFO), in case we ever decide to do so.  The
274 * NT_PRPSINFO and NT_PSINFO sections are always in order and adjacent;
275 * the SunOS 5.x file command relies on this (and prefers the latter).
276 *
277 * The signal number probably appears in a section of type NT_PRSTATUS,
278 * but that's also rather OS-dependent, in ways that are harder to
279 * dissect with heuristics, so I'm not bothering with the signal number.
280 * (I suppose the signal number could be of interest in situations where
281 * you don't have the binary of the program that dropped core; if you
282 * *do* have that binary, the debugger will probably tell you what
283 * signal it was.)
284 */
285
286#define	OS_STYLE_SVR4		0
287#define	OS_STYLE_FREEBSD	1
288#define	OS_STYLE_NETBSD		2
289
290private const char os_style_names[][8] = {
291	"SVR4",
292	"FreeBSD",
293	"NetBSD",
294};
295
296#define FLAGS_DID_CORE			0x001
297#define FLAGS_DID_OS_NOTE		0x002
298#define FLAGS_DID_BUILD_ID		0x004
299#define FLAGS_DID_CORE_STYLE		0x008
300#define FLAGS_DID_NETBSD_PAX		0x010
301#define FLAGS_DID_NETBSD_MARCH		0x020
302#define FLAGS_DID_NETBSD_CMODEL		0x040
303#define FLAGS_DID_NETBSD_UNKNOWN	0x080
304#define FLAGS_IS_CORE			0x100
305
306private int
307dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
308    int num, size_t size, off_t fsize, int *flags, uint16_t *notecount)
309{
310	Elf32_Phdr ph32;
311	Elf64_Phdr ph64;
312	size_t offset, len;
313	unsigned char nbuf[BUFSIZ];
314	ssize_t bufsize;
315
316	if (size != xph_sizeof) {
317		if (file_printf(ms, ", corrupted program header size") == -1)
318			return -1;
319		return 0;
320	}
321
322	/*
323	 * Loop through all the program headers.
324	 */
325	for ( ; num; num--) {
326		if (pread(fd, xph_addr, xph_sizeof, off) < (ssize_t)xph_sizeof) {
327			file_badread(ms);
328			return -1;
329		}
330		off += size;
331
332		if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
333			/* Perhaps warn here */
334			continue;
335		}
336
337		if (xph_type != PT_NOTE)
338			continue;
339
340		/*
341		 * This is a PT_NOTE section; loop through all the notes
342		 * in the section.
343		 */
344		len = xph_filesz < sizeof(nbuf) ? xph_filesz : sizeof(nbuf);
345		if ((bufsize = pread(fd, nbuf, len, xph_offset)) == -1) {
346			file_badread(ms);
347			return -1;
348		}
349		offset = 0;
350		for (;;) {
351			if (offset >= (size_t)bufsize)
352				break;
353			offset = donote(ms, nbuf, offset, (size_t)bufsize,
354			    clazz, swap, 4, flags, notecount);
355			if (offset == 0)
356				break;
357
358		}
359	}
360	return 0;
361}
362#endif
363
364static void
365do_note_netbsd_version(struct magic_set *ms, int swap, void *v)
366{
367	uint32_t desc;
368	(void)memcpy(&desc, v, sizeof(desc));
369	desc = elf_getu32(swap, desc);
370
371	if (file_printf(ms, ", for NetBSD") == -1)
372		return;
373	/*
374	 * The version number used to be stuck as 199905, and was thus
375	 * basically content-free.  Newer versions of NetBSD have fixed
376	 * this and now use the encoding of __NetBSD_Version__:
377	 *
378	 *	MMmmrrpp00
379	 *
380	 * M = major version
381	 * m = minor version
382	 * r = release ["",A-Z,Z[A-Z] but numeric]
383	 * p = patchlevel
384	 */
385	if (desc > 100000000U) {
386		uint32_t ver_patch = (desc / 100) % 100;
387		uint32_t ver_rel = (desc / 10000) % 100;
388		uint32_t ver_min = (desc / 1000000) % 100;
389		uint32_t ver_maj = desc / 100000000;
390
391		if (file_printf(ms, " %u.%u", ver_maj, ver_min) == -1)
392			return;
393		if (ver_rel == 0 && ver_patch != 0) {
394			if (file_printf(ms, ".%u", ver_patch) == -1)
395				return;
396		} else if (ver_rel != 0) {
397			while (ver_rel > 26) {
398				if (file_printf(ms, "Z") == -1)
399					return;
400				ver_rel -= 26;
401			}
402			if (file_printf(ms, "%c", 'A' + ver_rel - 1)
403			    == -1)
404				return;
405		}
406	}
407}
408
409static void
410do_note_freebsd_version(struct magic_set *ms, int swap, void *v)
411{
412	uint32_t desc;
413
414	(void)memcpy(&desc, v, sizeof(desc));
415	desc = elf_getu32(swap, desc);
416	if (file_printf(ms, ", for FreeBSD") == -1)
417		return;
418
419	/*
420	 * Contents is __FreeBSD_version, whose relation to OS
421	 * versions is defined by a huge table in the Porter's
422	 * Handbook.  This is the general scheme:
423	 *
424	 * Releases:
425	 * 	Mmp000 (before 4.10)
426	 * 	Mmi0p0 (before 5.0)
427	 * 	Mmm0p0
428	 *
429	 * Development branches:
430	 * 	Mmpxxx (before 4.6)
431	 * 	Mmp1xx (before 4.10)
432	 * 	Mmi1xx (before 5.0)
433	 * 	M000xx (pre-M.0)
434	 * 	Mmm1xx
435	 *
436	 * M = major version
437	 * m = minor version
438	 * i = minor version increment (491000 -> 4.10)
439	 * p = patchlevel
440	 * x = revision
441	 *
442	 * The first release of FreeBSD to use ELF by default
443	 * was version 3.0.
444	 */
445	if (desc == 460002) {
446		if (file_printf(ms, " 4.6.2") == -1)
447			return;
448	} else if (desc < 460100) {
449		if (file_printf(ms, " %d.%d", desc / 100000,
450		    desc / 10000 % 10) == -1)
451			return;
452		if (desc / 1000 % 10 > 0)
453			if (file_printf(ms, ".%d", desc / 1000 % 10) == -1)
454				return;
455		if ((desc % 1000 > 0) || (desc % 100000 == 0))
456			if (file_printf(ms, " (%d)", desc) == -1)
457				return;
458	} else if (desc < 500000) {
459		if (file_printf(ms, " %d.%d", desc / 100000,
460		    desc / 10000 % 10 + desc / 1000 % 10) == -1)
461			return;
462		if (desc / 100 % 10 > 0) {
463			if (file_printf(ms, " (%d)", desc) == -1)
464				return;
465		} else if (desc / 10 % 10 > 0) {
466			if (file_printf(ms, ".%d", desc / 10 % 10) == -1)
467				return;
468		}
469	} else {
470		if (file_printf(ms, " %d.%d", desc / 100000,
471		    desc / 1000 % 100) == -1)
472			return;
473		if ((desc / 100 % 10 > 0) ||
474		    (desc % 100000 / 100 == 0)) {
475			if (file_printf(ms, " (%d)", desc) == -1)
476				return;
477		} else if (desc / 10 % 10 > 0) {
478			if (file_printf(ms, ".%d", desc / 10 % 10) == -1)
479				return;
480		}
481	}
482}
483
484private int
485do_bid_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
486    int swap __attribute__((__unused__)), uint32_t namesz, uint32_t descsz,
487    size_t noff, size_t doff, int *flags)
488{
489	if (namesz == 4 && strcmp((char *)&nbuf[noff], "GNU") == 0 &&
490	    type == NT_GNU_BUILD_ID && (descsz == 16 || descsz == 20)) {
491		uint8_t desc[20];
492		uint32_t i;
493		*flags |= FLAGS_DID_BUILD_ID;
494		if (file_printf(ms, ", BuildID[%s]=", descsz == 16 ? "md5/uuid" :
495		    "sha1") == -1)
496			return 1;
497		(void)memcpy(desc, &nbuf[doff], descsz);
498		for (i = 0; i < descsz; i++)
499		    if (file_printf(ms, "%02x", desc[i]) == -1)
500			return 1;
501		return 1;
502	}
503	return 0;
504}
505
506private int
507do_os_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
508    int swap, uint32_t namesz, uint32_t descsz,
509    size_t noff, size_t doff, int *flags)
510{
511	if (namesz == 5 && strcmp((char *)&nbuf[noff], "SuSE") == 0 &&
512	    type == NT_GNU_VERSION && descsz == 2) {
513	    *flags |= FLAGS_DID_OS_NOTE;
514	    file_printf(ms, ", for SuSE %d.%d", nbuf[doff], nbuf[doff + 1]);
515	    return 1;
516	}
517
518	if (namesz == 4 && strcmp((char *)&nbuf[noff], "GNU") == 0 &&
519	    type == NT_GNU_VERSION && descsz == 16) {
520		uint32_t desc[4];
521		(void)memcpy(desc, &nbuf[doff], sizeof(desc));
522
523		*flags |= FLAGS_DID_OS_NOTE;
524		if (file_printf(ms, ", for GNU/") == -1)
525			return 1;
526		switch (elf_getu32(swap, desc[0])) {
527		case GNU_OS_LINUX:
528			if (file_printf(ms, "Linux") == -1)
529				return 1;
530			break;
531		case GNU_OS_HURD:
532			if (file_printf(ms, "Hurd") == -1)
533				return 1;
534			break;
535		case GNU_OS_SOLARIS:
536			if (file_printf(ms, "Solaris") == -1)
537				return 1;
538			break;
539		case GNU_OS_KFREEBSD:
540			if (file_printf(ms, "kFreeBSD") == -1)
541				return 1;
542			break;
543		case GNU_OS_KNETBSD:
544			if (file_printf(ms, "kNetBSD") == -1)
545				return 1;
546			break;
547		default:
548			if (file_printf(ms, "<unknown>") == -1)
549				return 1;
550		}
551		if (file_printf(ms, " %d.%d.%d", elf_getu32(swap, desc[1]),
552		    elf_getu32(swap, desc[2]), elf_getu32(swap, desc[3])) == -1)
553			return 1;
554		return 1;
555	}
556
557	if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0) {
558	    	if (type == NT_NETBSD_VERSION && descsz == 4) {
559			*flags |= FLAGS_DID_OS_NOTE;
560			do_note_netbsd_version(ms, swap, &nbuf[doff]);
561			return 1;
562		}
563	}
564
565	if (namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0) {
566	    	if (type == NT_FREEBSD_VERSION && descsz == 4) {
567			*flags |= FLAGS_DID_OS_NOTE;
568			do_note_freebsd_version(ms, swap, &nbuf[doff]);
569			return 1;
570		}
571	}
572
573	if (namesz == 8 && strcmp((char *)&nbuf[noff], "OpenBSD") == 0 &&
574	    type == NT_OPENBSD_VERSION && descsz == 4) {
575		*flags |= FLAGS_DID_OS_NOTE;
576		if (file_printf(ms, ", for OpenBSD") == -1)
577			return 1;
578		/* Content of note is always 0 */
579		return 1;
580	}
581
582	if (namesz == 10 && strcmp((char *)&nbuf[noff], "DragonFly") == 0 &&
583	    type == NT_DRAGONFLY_VERSION && descsz == 4) {
584		uint32_t desc;
585		*flags |= FLAGS_DID_OS_NOTE;
586		if (file_printf(ms, ", for DragonFly") == -1)
587			return 1;
588		(void)memcpy(&desc, &nbuf[doff], sizeof(desc));
589		desc = elf_getu32(swap, desc);
590		if (file_printf(ms, " %d.%d.%d", desc / 100000,
591		    desc / 10000 % 10, desc % 10000) == -1)
592			return 1;
593		return 1;
594	}
595	return 0;
596}
597
598private int
599do_pax_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
600    int swap, uint32_t namesz, uint32_t descsz,
601    size_t noff, size_t doff, int *flags)
602{
603	if (namesz == 4 && strcmp((char *)&nbuf[noff], "PaX") == 0 &&
604	    type == NT_NETBSD_PAX && descsz == 4) {
605		static const char *pax[] = {
606		    "+mprotect",
607		    "-mprotect",
608		    "+segvguard",
609		    "-segvguard",
610		    "+ASLR",
611		    "-ASLR",
612		};
613		uint32_t desc;
614		size_t i;
615		int did = 0;
616
617		*flags |= FLAGS_DID_NETBSD_PAX;
618		(void)memcpy(&desc, &nbuf[doff], sizeof(desc));
619		desc = elf_getu32(swap, desc);
620
621		if (desc && file_printf(ms, ", PaX: ") == -1)
622			return 1;
623
624		for (i = 0; i < __arraycount(pax); i++) {
625			if (((1 << i) & desc) == 0)
626				continue;
627			if (file_printf(ms, "%s%s", did++ ? "," : "",
628			    pax[i]) == -1)
629				return 1;
630		}
631		return 1;
632	}
633	return 0;
634}
635
636private int
637do_core_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
638    int swap, uint32_t namesz, uint32_t descsz,
639    size_t noff, size_t doff, int *flags, size_t size, int clazz)
640{
641#ifdef ELFCORE
642	int os_style = -1;
643	/*
644	 * Sigh.  The 2.0.36 kernel in Debian 2.1, at
645	 * least, doesn't correctly implement name
646	 * sections, in core dumps, as specified by
647	 * the "Program Linking" section of "UNIX(R) System
648	 * V Release 4 Programmer's Guide: ANSI C and
649	 * Programming Support Tools", because my copy
650	 * clearly says "The first 'namesz' bytes in 'name'
651	 * contain a *null-terminated* [emphasis mine]
652	 * character representation of the entry's owner
653	 * or originator", but the 2.0.36 kernel code
654	 * doesn't include the terminating null in the
655	 * name....
656	 */
657	if ((namesz == 4 && strncmp((char *)&nbuf[noff], "CORE", 4) == 0) ||
658	    (namesz == 5 && strcmp((char *)&nbuf[noff], "CORE") == 0)) {
659		os_style = OS_STYLE_SVR4;
660	}
661
662	if ((namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0)) {
663		os_style = OS_STYLE_FREEBSD;
664	}
665
666	if ((namesz >= 11 && strncmp((char *)&nbuf[noff], "NetBSD-CORE", 11)
667	    == 0)) {
668		os_style = OS_STYLE_NETBSD;
669	}
670
671	if (os_style != -1 && (*flags & FLAGS_DID_CORE_STYLE) == 0) {
672		if (file_printf(ms, ", %s-style", os_style_names[os_style])
673		    == -1)
674			return 1;
675		*flags |= FLAGS_DID_CORE_STYLE;
676	}
677
678	switch (os_style) {
679	case OS_STYLE_NETBSD:
680		if (type == NT_NETBSD_CORE_PROCINFO) {
681			char sbuf[512];
682			uint32_t signo;
683			/*
684			 * Extract the program name.  It is at
685			 * offset 0x7c, and is up to 32-bytes,
686			 * including the terminating NUL.
687			 */
688			if (file_printf(ms, ", from '%.31s'",
689			    file_printable(sbuf, sizeof(sbuf),
690			    (const char *)&nbuf[doff + 0x7c])) == -1)
691				return 1;
692
693			/*
694			 * Extract the signal number.  It is at
695			 * offset 0x08.
696			 */
697			(void)memcpy(&signo, &nbuf[doff + 0x08],
698			    sizeof(signo));
699			if (file_printf(ms, " (signal %u)",
700			    elf_getu32(swap, signo)) == -1)
701				return 1;
702			*flags |= FLAGS_DID_CORE;
703			return 1;
704		}
705		break;
706
707	default:
708		if (type == NT_PRPSINFO && *flags & FLAGS_IS_CORE) {
709			size_t i, j;
710			unsigned char c;
711			/*
712			 * Extract the program name.  We assume
713			 * it to be 16 characters (that's what it
714			 * is in SunOS 5.x and Linux).
715			 *
716			 * Unfortunately, it's at a different offset
717			 * in various OSes, so try multiple offsets.
718			 * If the characters aren't all printable,
719			 * reject it.
720			 */
721			for (i = 0; i < NOFFSETS; i++) {
722				unsigned char *cname, *cp;
723				size_t reloffset = prpsoffsets(i);
724				size_t noffset = doff + reloffset;
725				size_t k;
726				for (j = 0; j < 16; j++, noffset++,
727				    reloffset++) {
728					/*
729					 * Make sure we're not past
730					 * the end of the buffer; if
731					 * we are, just give up.
732					 */
733					if (noffset >= size)
734						goto tryanother;
735
736					/*
737					 * Make sure we're not past
738					 * the end of the contents;
739					 * if we are, this obviously
740					 * isn't the right offset.
741					 */
742					if (reloffset >= descsz)
743						goto tryanother;
744
745					c = nbuf[noffset];
746					if (c == '\0') {
747						/*
748						 * A '\0' at the
749						 * beginning is
750						 * obviously wrong.
751						 * Any other '\0'
752						 * means we're done.
753						 */
754						if (j == 0)
755							goto tryanother;
756						else
757							break;
758					} else {
759						/*
760						 * A nonprintable
761						 * character is also
762						 * wrong.
763						 */
764						if (!isprint(c) || isquote(c))
765							goto tryanother;
766					}
767				}
768				/*
769				 * Well, that worked.
770				 */
771
772				/*
773				 * Try next offsets, in case this match is
774				 * in the middle of a string.
775				 */
776				for (k = i + 1 ; k < NOFFSETS; k++) {
777					size_t no;
778					int adjust = 1;
779					if (prpsoffsets(k) >= prpsoffsets(i))
780						continue;
781					for (no = doff + prpsoffsets(k);
782					     no < doff + prpsoffsets(i); no++)
783						adjust = adjust
784						         && isprint(nbuf[no]);
785					if (adjust)
786						i = k;
787				}
788
789				cname = (unsigned char *)
790				    &nbuf[doff + prpsoffsets(i)];
791				for (cp = cname; *cp && isprint(*cp); cp++)
792					continue;
793				/*
794				 * Linux apparently appends a space at the end
795				 * of the command line: remove it.
796				 */
797				while (cp > cname && isspace(cp[-1]))
798					cp--;
799				if (file_printf(ms, ", from '%.*s'",
800				    (int)(cp - cname), cname) == -1)
801					return 1;
802				*flags |= FLAGS_DID_CORE;
803				return 1;
804
805			tryanother:
806				;
807			}
808		}
809		break;
810	}
811#endif
812	return 0;
813}
814
815private size_t
816donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size,
817    int clazz, int swap, size_t align, int *flags, uint16_t *notecount)
818{
819	Elf32_Nhdr nh32;
820	Elf64_Nhdr nh64;
821	size_t noff, doff;
822	uint32_t namesz, descsz;
823	unsigned char *nbuf = CAST(unsigned char *, vbuf);
824
825	if (*notecount == 0)
826		return 0;
827	--*notecount;
828
829	if (xnh_sizeof + offset > size) {
830		/*
831		 * We're out of note headers.
832		 */
833		return xnh_sizeof + offset;
834	}
835
836	(void)memcpy(xnh_addr, &nbuf[offset], xnh_sizeof);
837	offset += xnh_sizeof;
838
839	namesz = xnh_namesz;
840	descsz = xnh_descsz;
841	if ((namesz == 0) && (descsz == 0)) {
842		/*
843		 * We're out of note headers.
844		 */
845		return (offset >= size) ? offset : size;
846	}
847
848	if (namesz & 0x80000000) {
849	    (void)file_printf(ms, ", bad note name size 0x%lx",
850		(unsigned long)namesz);
851	    return 0;
852	}
853
854	if (descsz & 0x80000000) {
855	    (void)file_printf(ms, ", bad note description size 0x%lx",
856		(unsigned long)descsz);
857	    return 0;
858	}
859
860	noff = offset;
861	doff = ELF_ALIGN(offset + namesz);
862
863	if (offset + namesz > size) {
864		/*
865		 * We're past the end of the buffer.
866		 */
867		return doff;
868	}
869
870	offset = ELF_ALIGN(doff + descsz);
871	if (doff + descsz > size) {
872		/*
873		 * We're past the end of the buffer.
874		 */
875		return (offset >= size) ? offset : size;
876	}
877
878	if ((*flags & FLAGS_DID_OS_NOTE) == 0) {
879		if (do_os_note(ms, nbuf, xnh_type, swap,
880		    namesz, descsz, noff, doff, flags))
881			return size;
882	}
883
884	if ((*flags & FLAGS_DID_BUILD_ID) == 0) {
885		if (do_bid_note(ms, nbuf, xnh_type, swap,
886		    namesz, descsz, noff, doff, flags))
887			return size;
888	}
889
890	if ((*flags & FLAGS_DID_NETBSD_PAX) == 0) {
891		if (do_pax_note(ms, nbuf, xnh_type, swap,
892		    namesz, descsz, noff, doff, flags))
893			return size;
894	}
895
896	if ((*flags & FLAGS_DID_CORE) == 0) {
897		if (do_core_note(ms, nbuf, xnh_type, swap,
898		    namesz, descsz, noff, doff, flags, size, clazz))
899			return size;
900	}
901
902	if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0) {
903		if (descsz > 100)
904			descsz = 100;
905		switch (xnh_type) {
906	    	case NT_NETBSD_VERSION:
907			return size;
908		case NT_NETBSD_MARCH:
909			if (*flags & FLAGS_DID_NETBSD_MARCH)
910				return size;
911			*flags |= FLAGS_DID_NETBSD_MARCH;
912			if (file_printf(ms, ", compiled for: %.*s",
913			    (int)descsz, (const char *)&nbuf[doff]) == -1)
914				return size;
915			break;
916		case NT_NETBSD_CMODEL:
917			if (*flags & FLAGS_DID_NETBSD_CMODEL)
918				return size;
919			*flags |= FLAGS_DID_NETBSD_CMODEL;
920			if (file_printf(ms, ", compiler model: %.*s",
921			    (int)descsz, (const char *)&nbuf[doff]) == -1)
922				return size;
923			break;
924		default:
925			if (*flags & FLAGS_DID_NETBSD_UNKNOWN)
926				return size;
927			*flags |= FLAGS_DID_NETBSD_UNKNOWN;
928			if (file_printf(ms, ", note=%u", xnh_type) == -1)
929				return size;
930			break;
931		}
932		return size;
933	}
934
935	return offset;
936}
937
938/* SunOS 5.x hardware capability descriptions */
939typedef struct cap_desc {
940	uint64_t cd_mask;
941	const char *cd_name;
942} cap_desc_t;
943
944static const cap_desc_t cap_desc_sparc[] = {
945	{ AV_SPARC_MUL32,		"MUL32" },
946	{ AV_SPARC_DIV32,		"DIV32" },
947	{ AV_SPARC_FSMULD,		"FSMULD" },
948	{ AV_SPARC_V8PLUS,		"V8PLUS" },
949	{ AV_SPARC_POPC,		"POPC" },
950	{ AV_SPARC_VIS,			"VIS" },
951	{ AV_SPARC_VIS2,		"VIS2" },
952	{ AV_SPARC_ASI_BLK_INIT,	"ASI_BLK_INIT" },
953	{ AV_SPARC_FMAF,		"FMAF" },
954	{ AV_SPARC_FJFMAU,		"FJFMAU" },
955	{ AV_SPARC_IMA,			"IMA" },
956	{ 0, NULL }
957};
958
959static const cap_desc_t cap_desc_386[] = {
960	{ AV_386_FPU,			"FPU" },
961	{ AV_386_TSC,			"TSC" },
962	{ AV_386_CX8,			"CX8" },
963	{ AV_386_SEP,			"SEP" },
964	{ AV_386_AMD_SYSC,		"AMD_SYSC" },
965	{ AV_386_CMOV,			"CMOV" },
966	{ AV_386_MMX,			"MMX" },
967	{ AV_386_AMD_MMX,		"AMD_MMX" },
968	{ AV_386_AMD_3DNow,		"AMD_3DNow" },
969	{ AV_386_AMD_3DNowx,		"AMD_3DNowx" },
970	{ AV_386_FXSR,			"FXSR" },
971	{ AV_386_SSE,			"SSE" },
972	{ AV_386_SSE2,			"SSE2" },
973	{ AV_386_PAUSE,			"PAUSE" },
974	{ AV_386_SSE3,			"SSE3" },
975	{ AV_386_MON,			"MON" },
976	{ AV_386_CX16,			"CX16" },
977	{ AV_386_AHF,			"AHF" },
978	{ AV_386_TSCP,			"TSCP" },
979	{ AV_386_AMD_SSE4A,		"AMD_SSE4A" },
980	{ AV_386_POPCNT,		"POPCNT" },
981	{ AV_386_AMD_LZCNT,		"AMD_LZCNT" },
982	{ AV_386_SSSE3,			"SSSE3" },
983	{ AV_386_SSE4_1,		"SSE4.1" },
984	{ AV_386_SSE4_2,		"SSE4.2" },
985	{ 0, NULL }
986};
987
988private int
989doshn(struct magic_set *ms, int clazz, int swap, int fd, off_t off, int num,
990    size_t size, off_t fsize, int mach, int strtab, int *flags,
991    uint16_t *notecount)
992{
993	Elf32_Shdr sh32;
994	Elf64_Shdr sh64;
995	int stripped = 1;
996	size_t nbadcap = 0;
997	void *nbuf;
998	off_t noff, coff, name_off;
999	uint64_t cap_hw1 = 0;	/* SunOS 5.x hardware capabilites */
1000	uint64_t cap_sf1 = 0;	/* SunOS 5.x software capabilites */
1001	char name[50];
1002	ssize_t namesize;
1003
1004	if (size != xsh_sizeof) {
1005		if (file_printf(ms, ", corrupted section header size") == -1)
1006			return -1;
1007		return 0;
1008	}
1009
1010	/* Read offset of name section to be able to read section names later */
1011	if (pread(fd, xsh_addr, xsh_sizeof, off + size * strtab) < (ssize_t)xsh_sizeof) {
1012		file_badread(ms);
1013		return -1;
1014	}
1015	name_off = xsh_offset;
1016
1017	for ( ; num; num--) {
1018		/* Read the name of this section. */
1019		if ((namesize = pread(fd, name, sizeof(name) - 1, name_off + xsh_name)) == -1) {
1020			file_badread(ms);
1021			return -1;
1022		}
1023		name[namesize] = '\0';
1024		if (strcmp(name, ".debug_info") == 0)
1025			stripped = 0;
1026
1027		if (pread(fd, xsh_addr, xsh_sizeof, off) < (ssize_t)xsh_sizeof) {
1028			file_badread(ms);
1029			return -1;
1030		}
1031		off += size;
1032
1033		/* Things we can determine before we seek */
1034		switch (xsh_type) {
1035		case SHT_SYMTAB:
1036#if 0
1037		case SHT_DYNSYM:
1038#endif
1039			stripped = 0;
1040			break;
1041		default:
1042			if (fsize != SIZE_UNKNOWN && xsh_offset > fsize) {
1043				/* Perhaps warn here */
1044				continue;
1045			}
1046			break;
1047		}
1048
1049		/* Things we can determine when we seek */
1050		switch (xsh_type) {
1051		case SHT_NOTE:
1052			if ((nbuf = malloc(xsh_size)) == NULL) {
1053				file_error(ms, errno, "Cannot allocate memory"
1054				    " for note");
1055				return -1;
1056			}
1057			if (pread(fd, nbuf, xsh_size, xsh_offset) < (ssize_t)xsh_size) {
1058				file_badread(ms);
1059				free(nbuf);
1060				return -1;
1061			}
1062
1063			noff = 0;
1064			for (;;) {
1065				if (noff >= (off_t)xsh_size)
1066					break;
1067				noff = donote(ms, nbuf, (size_t)noff,
1068				    xsh_size, clazz, swap, 4, flags, notecount);
1069				if (noff == 0)
1070					break;
1071			}
1072			free(nbuf);
1073			break;
1074		case SHT_SUNW_cap:
1075			switch (mach) {
1076			case EM_SPARC:
1077			case EM_SPARCV9:
1078			case EM_IA_64:
1079			case EM_386:
1080			case EM_AMD64:
1081				break;
1082			default:
1083				goto skip;
1084			}
1085
1086			if (nbadcap > 5)
1087				break;
1088			if (lseek(fd, xsh_offset, SEEK_SET) == (off_t)-1) {
1089				file_badseek(ms);
1090				return -1;
1091			}
1092			coff = 0;
1093			for (;;) {
1094				Elf32_Cap cap32;
1095				Elf64_Cap cap64;
1096				char cbuf[/*CONSTCOND*/
1097				    MAX(sizeof cap32, sizeof cap64)];
1098				if ((coff += xcap_sizeof) > (off_t)xsh_size)
1099					break;
1100				if (read(fd, cbuf, (size_t)xcap_sizeof) !=
1101				    (ssize_t)xcap_sizeof) {
1102					file_badread(ms);
1103					return -1;
1104				}
1105				if (cbuf[0] == 'A') {
1106#ifdef notyet
1107					char *p = cbuf + 1;
1108					uint32_t len, tag;
1109					memcpy(&len, p, sizeof(len));
1110					p += 4;
1111					len = getu32(swap, len);
1112					if (memcmp("gnu", p, 3) != 0) {
1113					    if (file_printf(ms,
1114						", unknown capability %.3s", p)
1115						== -1)
1116						return -1;
1117					    break;
1118					}
1119					p += strlen(p) + 1;
1120					tag = *p++;
1121					memcpy(&len, p, sizeof(len));
1122					p += 4;
1123					len = getu32(swap, len);
1124					if (tag != 1) {
1125					    if (file_printf(ms, ", unknown gnu"
1126						" capability tag %d", tag)
1127						== -1)
1128						return -1;
1129					    break;
1130					}
1131					// gnu attributes
1132#endif
1133					break;
1134				}
1135				(void)memcpy(xcap_addr, cbuf, xcap_sizeof);
1136				switch (xcap_tag) {
1137				case CA_SUNW_NULL:
1138					break;
1139				case CA_SUNW_HW_1:
1140					cap_hw1 |= xcap_val;
1141					break;
1142				case CA_SUNW_SF_1:
1143					cap_sf1 |= xcap_val;
1144					break;
1145				default:
1146					if (file_printf(ms,
1147					    ", with unknown capability "
1148					    "0x%" INT64_T_FORMAT "x = 0x%"
1149					    INT64_T_FORMAT "x",
1150					    (unsigned long long)xcap_tag,
1151					    (unsigned long long)xcap_val) == -1)
1152						return -1;
1153					if (nbadcap++ > 2)
1154						coff = xsh_size;
1155					break;
1156				}
1157			}
1158			/*FALLTHROUGH*/
1159		skip:
1160		default:
1161			break;
1162		}
1163	}
1164
1165	if (file_printf(ms, ", %sstripped", stripped ? "" : "not ") == -1)
1166		return -1;
1167	if (cap_hw1) {
1168		const cap_desc_t *cdp;
1169		switch (mach) {
1170		case EM_SPARC:
1171		case EM_SPARC32PLUS:
1172		case EM_SPARCV9:
1173			cdp = cap_desc_sparc;
1174			break;
1175		case EM_386:
1176		case EM_IA_64:
1177		case EM_AMD64:
1178			cdp = cap_desc_386;
1179			break;
1180		default:
1181			cdp = NULL;
1182			break;
1183		}
1184		if (file_printf(ms, ", uses") == -1)
1185			return -1;
1186		if (cdp) {
1187			while (cdp->cd_name) {
1188				if (cap_hw1 & cdp->cd_mask) {
1189					if (file_printf(ms,
1190					    " %s", cdp->cd_name) == -1)
1191						return -1;
1192					cap_hw1 &= ~cdp->cd_mask;
1193				}
1194				++cdp;
1195			}
1196			if (cap_hw1)
1197				if (file_printf(ms,
1198				    " unknown hardware capability 0x%"
1199				    INT64_T_FORMAT "x",
1200				    (unsigned long long)cap_hw1) == -1)
1201					return -1;
1202		} else {
1203			if (file_printf(ms,
1204			    " hardware capability 0x%" INT64_T_FORMAT "x",
1205			    (unsigned long long)cap_hw1) == -1)
1206				return -1;
1207		}
1208	}
1209	if (cap_sf1) {
1210		if (cap_sf1 & SF1_SUNW_FPUSED) {
1211			if (file_printf(ms,
1212			    (cap_sf1 & SF1_SUNW_FPKNWN)
1213			    ? ", uses frame pointer"
1214			    : ", not known to use frame pointer") == -1)
1215				return -1;
1216		}
1217		cap_sf1 &= ~SF1_SUNW_MASK;
1218		if (cap_sf1)
1219			if (file_printf(ms,
1220			    ", with unknown software capability 0x%"
1221			    INT64_T_FORMAT "x",
1222			    (unsigned long long)cap_sf1) == -1)
1223				return -1;
1224	}
1225	return 0;
1226}
1227
1228/*
1229 * Look through the program headers of an executable image, searching
1230 * for a PT_INTERP section; if one is found, it's dynamically linked,
1231 * otherwise it's statically linked.
1232 */
1233private int
1234dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
1235    int num, size_t size, off_t fsize, int sh_num, int *flags,
1236    uint16_t *notecount)
1237{
1238	Elf32_Phdr ph32;
1239	Elf64_Phdr ph64;
1240	const char *linking_style = "statically";
1241	const char *interp = "";
1242	unsigned char nbuf[BUFSIZ];
1243	char ibuf[BUFSIZ];
1244	ssize_t bufsize;
1245	size_t offset, align, len;
1246
1247	if (size != xph_sizeof) {
1248		if (file_printf(ms, ", corrupted program header size") == -1)
1249			return -1;
1250		return 0;
1251	}
1252
1253  	for ( ; num; num--) {
1254		if (pread(fd, xph_addr, xph_sizeof, off) < (ssize_t)xph_sizeof) {
1255			file_badread(ms);
1256			return -1;
1257		}
1258
1259		off += size;
1260		bufsize = 0;
1261		align = 4;
1262
1263		/* Things we can determine before we seek */
1264		switch (xph_type) {
1265		case PT_DYNAMIC:
1266			linking_style = "dynamically";
1267			break;
1268		case PT_NOTE:
1269			if (sh_num)	/* Did this through section headers */
1270				continue;
1271			if (((align = xph_align) & 0x80000000UL) != 0 ||
1272			    align < 4) {
1273				if (file_printf(ms,
1274				    ", invalid note alignment 0x%lx",
1275				    (unsigned long)align) == -1)
1276					return -1;
1277				align = 4;
1278			}
1279			/*FALLTHROUGH*/
1280		case PT_INTERP:
1281			len = xph_filesz < sizeof(nbuf) ? xph_filesz
1282			    : sizeof(nbuf);
1283			bufsize = pread(fd, nbuf, len, xph_offset);
1284			if (bufsize == -1) {
1285				file_badread(ms);
1286				return -1;
1287			}
1288			break;
1289		default:
1290			if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
1291				/* Maybe warn here? */
1292				continue;
1293			}
1294			break;
1295		}
1296
1297		/* Things we can determine when we seek */
1298		switch (xph_type) {
1299		case PT_INTERP:
1300			if (bufsize && nbuf[0]) {
1301				nbuf[bufsize - 1] = '\0';
1302				interp = (const char *)nbuf;
1303			} else
1304				interp = "*empty*";
1305			break;
1306		case PT_NOTE:
1307			/*
1308			 * This is a PT_NOTE section; loop through all the notes
1309			 * in the section.
1310			 */
1311			offset = 0;
1312			for (;;) {
1313				if (offset >= (size_t)bufsize)
1314					break;
1315				offset = donote(ms, nbuf, offset,
1316				    (size_t)bufsize, clazz, swap, align,
1317				    flags, notecount);
1318				if (offset == 0)
1319					break;
1320			}
1321			break;
1322		default:
1323			break;
1324		}
1325	}
1326	if (file_printf(ms, ", %s linked", linking_style)
1327	    == -1)
1328		return -1;
1329	if (interp[0])
1330		if (file_printf(ms, ", interpreter %s",
1331		    file_printable(ibuf, sizeof(ibuf), interp)) == -1)
1332			return -1;
1333	return 0;
1334}
1335
1336
1337protected int
1338file_tryelf(struct magic_set *ms, int fd, const unsigned char *buf,
1339    size_t nbytes)
1340{
1341	union {
1342		int32_t l;
1343		char c[sizeof (int32_t)];
1344	} u;
1345	int clazz;
1346	int swap;
1347	struct stat st;
1348	off_t fsize;
1349	int flags = 0;
1350	Elf32_Ehdr elf32hdr;
1351	Elf64_Ehdr elf64hdr;
1352	uint16_t type, phnum, shnum, notecount;
1353
1354	if (ms->flags & (MAGIC_MIME|MAGIC_APPLE))
1355		return 0;
1356	/*
1357	 * ELF executables have multiple section headers in arbitrary
1358	 * file locations and thus file(1) cannot determine it from easily.
1359	 * Instead we traverse thru all section headers until a symbol table
1360	 * one is found or else the binary is stripped.
1361	 * Return immediately if it's not ELF (so we avoid pipe2file unless needed).
1362	 */
1363	if (buf[EI_MAG0] != ELFMAG0
1364	    || (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
1365	    || buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
1366		return 0;
1367
1368	/*
1369	 * If we cannot seek, it must be a pipe, socket or fifo.
1370	 */
1371	if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
1372		fd = file_pipe2file(ms, fd, buf, nbytes);
1373
1374	if (fstat(fd, &st) == -1) {
1375  		file_badread(ms);
1376		return -1;
1377	}
1378	if (S_ISREG(st.st_mode) || st.st_size != 0)
1379		fsize = st.st_size;
1380	else
1381		fsize = SIZE_UNKNOWN;
1382
1383	clazz = buf[EI_CLASS];
1384
1385	switch (clazz) {
1386	case ELFCLASS32:
1387#undef elf_getu
1388#define elf_getu(a, b)	elf_getu32(a, b)
1389#undef elfhdr
1390#define elfhdr elf32hdr
1391#include "elfclass.h"
1392	case ELFCLASS64:
1393#undef elf_getu
1394#define elf_getu(a, b)	elf_getu64(a, b)
1395#undef elfhdr
1396#define elfhdr elf64hdr
1397#include "elfclass.h"
1398	default:
1399	    if (file_printf(ms, ", unknown class %d", clazz) == -1)
1400		    return -1;
1401	    break;
1402	}
1403	return 0;
1404}
1405#endif
1406