xref: /titanic_41/usr/src/cmd/sgs/libelf/common/ar.c (revision 1e49577a7fcde812700ded04431b49d67cc57d6d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  *	Copyright (c) 1988 AT&T
29  *	  All Rights Reserved
30  */
31 
32 #pragma ident	"%Z%%M%	%I%	%E% SMI"
33 
34 #include <ar.h>
35 #include <stdlib.h>
36 #include <memory.h>
37 #include <errno.h>
38 #include <libelf.h>
39 #include "decl.h"
40 #include "msg.h"
41 #include "member.h"
42 
43 #define	MANGLE	'\177'
44 
45 
46 /*
47  * Archive processing
48  *	When processing an archive member, two things can happen
49  *	that are a little tricky.
50  *
51  * Sliding
52  *	Sliding support is left in for backward compatibility and for
53  *	support of Archives produced on other systems.  The bundled
54  *	ar(1) produces archives with all members on a 4 byte boundry,
55  *	so current archives should need no sliding.
56  *
57  *	Archive members that are only 2-byte aligned within the file will
58  *	be slid.  To reuse the file's memory image, the library slides an
59  *	archive member into its header to align the bytes.  This means
60  *	the header must be disposable.
61  *
62  * Header reuse
63  *	Because the library can trample the header, it must be preserved to
64  *	avoid restrictions on archive member reuse.  That is, if the member
65  *	header changes, the library may see garbage the next time it looks
66  *	at the header.  After extracting the original header, the library
67  *	appends it to the parents `ed_memlist' list, thus future lookups first
68  *	check this list to determine if a member has previously been processed
69  *	and whether sliding occured.
70  */
71 
72 
73 /*
74  * Size check
75  *	If the header is too small, the following generates a negative
76  *	subscript for x.x and fails to compile.
77  *
78  * The check is based on sizeof (Elf64) because that's always going
79  * to be at least as big as Elf32.
80  */
81 
82 struct	x
83 {
84 	char	x[sizeof (struct ar_hdr) - 3 * sizeof (Elf64) - 1];
85 };
86 
87 
88 
89 static const char	fmag[] = ARFMAG;
90 
91 
92 /*
93  * Convert a string starting at 'p' and ending at 'end' into
94  * an integer.  Base is the base of the number being converted
95  * (either 8 or 10).
96  *
97  * Returns the converted integer of the string being scaned.
98  */
99 unsigned long
100 _elf_number(char *p, char *end, int base)
101 {
102 	register unsigned	c;
103 	register unsigned long	n = 0;
104 
105 	while (p < end) {
106 		if ((c = *p - '0') >= base) {
107 			while (*p++ == ' ')
108 				if (p >= end)
109 					return (n);
110 			return (0);
111 		}
112 		n *= base;
113 		n += c;
114 		++p;
115 	}
116 	return (n);
117 }
118 
119 
120 /*
121  * Convert ar_hdr to Member
122  *	Converts ascii file representation to the binary memory values.
123  */
124 Member *
125 _elf_armem(Elf *elf, char *file, size_t fsz)
126 {
127 	register struct ar_hdr	*f = (struct ar_hdr *)file;
128 	register Member		*m;
129 	register Memlist	*l, * ol;
130 	register Memident	*i;
131 
132 	if (fsz < sizeof (struct ar_hdr)) {
133 		_elf_seterr(EFMT_ARHDRSZ, 0);
134 		return (0);
135 	}
136 
137 	/*
138 	 * Determine in this member has already been processed
139 	 */
140 	for (l = elf->ed_memlist, ol = l; l; ol = l, l = l->m_next)
141 		for (i = (Memident *)(l + 1); i < l->m_free; i++)
142 			if (i->m_offset == file)
143 				return (i->m_member);
144 
145 	if (f->ar_fmag[0] != fmag[0] || f->ar_fmag[1] != fmag[1]) {
146 		_elf_seterr(EFMT_ARFMAG, 0);
147 		return (0);
148 	}
149 
150 	/*
151 	 * Allocate a new member structure and assign it to the next free
152 	 * free memlist ident.
153 	 */
154 	if ((m = (Member *)malloc(sizeof (Member))) == 0) {
155 		_elf_seterr(EMEM_ARMEM, errno);
156 		return (0);
157 	}
158 	if ((elf->ed_memlist == 0) || (ol->m_free == ol->m_end)) {
159 		if ((l = (Memlist *)malloc(sizeof (Memlist) +
160 		    (sizeof (Memident) * MEMIDENTNO))) == 0) {
161 			_elf_seterr(EMEM_ARMEM, errno);
162 			return (0);
163 		}
164 		l->m_next = 0;
165 		l->m_free = (Memident *)(l + 1);
166 		l->m_end = (Memident *)((uintptr_t)l->m_free +
167 		    (sizeof (Memident) * MEMIDENTNO));
168 
169 		if (elf->ed_memlist == 0)
170 			elf->ed_memlist = l;
171 		else
172 			ol->m_next = l;
173 		ol = l;
174 	}
175 	ol->m_free->m_offset = file;
176 	ol->m_free->m_member = m;
177 	ol->m_free++;
178 
179 	m->m_err = 0;
180 	(void) memcpy(m->m_name, f->ar_name, ARSZ(ar_name));
181 	m->m_name[ARSZ(ar_name)] = '\0';
182 	m->m_hdr.ar_name = m->m_name;
183 	(void) memcpy(m->m_raw, f->ar_name, ARSZ(ar_name));
184 	m->m_raw[ARSZ(ar_name)] = '\0';
185 	m->m_hdr.ar_rawname = m->m_raw;
186 	m->m_slide = 0;
187 
188 	/*
189 	 * Classify file name.
190 	 * If a name error occurs, delay until getarhdr().
191 	 */
192 
193 	if (f->ar_name[0] != '/') {	/* regular name */
194 		register char	*p;
195 
196 		p = &m->m_name[sizeof (m->m_name)];
197 		while (*--p != '/')
198 			if (p <= m->m_name)
199 				break;
200 		*p = '\0';
201 	} else if (f->ar_name[1] >= '0' && f->ar_name[1] <= '9') { /* strtab */
202 		register unsigned long	j;
203 
204 		j = _elf_number(&f->ar_name[1],
205 		    &f->ar_name[ARSZ(ar_name)], 10);
206 		if (j < elf->ed_arstrsz)
207 			m->m_hdr.ar_name = elf->ed_arstr + j;
208 		else {
209 			m->m_hdr.ar_name = 0;
210 			/*LINTED*/ /* MSG_INTL(EFMT_ARSTRNM) */
211 			m->m_err = (int)EFMT_ARSTRNM;
212 		}
213 	} else if (f->ar_name[1] == ' ')			/* "/" */
214 		m->m_name[1] = '\0';
215 	else if (f->ar_name[1] == '/' && f->ar_name[2] == ' ')	/* "//" */
216 		m->m_name[2] = '\0';
217 	else {							/* "/?" */
218 		m->m_hdr.ar_name = 0;
219 		/*LINTED*/ /* MSG_INTL(EFMT_ARUNKNM) */
220 		m->m_err = (int)EFMT_ARUNKNM;
221 	}
222 
223 	m->m_hdr.ar_date = (time_t)_elf_number(f->ar_date,
224 	    &f->ar_date[ARSZ(ar_date)], 10);
225 	/* LINTED */
226 	m->m_hdr.ar_uid = (uid_t)_elf_number(f->ar_uid,
227 	    &f->ar_uid[ARSZ(ar_uid)], 10);
228 	/* LINTED */
229 	m->m_hdr.ar_gid = (gid_t)_elf_number(f->ar_gid,
230 	    &f->ar_gid[ARSZ(ar_gid)], 10);
231 	/* LINTED */
232 	m->m_hdr.ar_mode = (mode_t)_elf_number(f->ar_mode,
233 	    &f->ar_mode[ARSZ(ar_mode)], 8);
234 	m->m_hdr.ar_size = (off_t)_elf_number(f->ar_size,
235 	    &f->ar_size[ARSZ(ar_size)], 10);
236 
237 	return (m);
238 }
239 
240 
241 /*
242  * Initial archive processing
243  *	An archive may have two special members.
244  *	A symbol table, named /, must be first if it is present.
245  *	A string table, named //, must precede all "normal" members.
246  *
247  *	This code "peeks" at headers but doesn't change them.
248  *	Later processing wants original headers.
249  *
250  *	String table is converted, changing '/' name terminators
251  *	to nulls.  The last byte in the string table, which should
252  *	be '\n', is set to nil, guaranteeing null termination.  That
253  *	byte should be '\n', but this code doesn't check.
254  *
255  *	The symbol table conversion is delayed until needed.
256  */
257 void
258 _elf_arinit(Elf * elf)
259 {
260 	char				*base = elf->ed_ident;
261 	register char			*end = base + elf->ed_fsz;
262 	register struct ar_hdr		*a;
263 	register char			*hdr = base + SARMAG;
264 	register char			*mem;
265 	int				j;
266 	size_t				sz = SARMAG;
267 
268 	elf->ed_status = ES_COOKED;
269 	elf->ed_nextoff = SARMAG;
270 	for (j = 0; j < 2; ++j)	 {	/* 2 special members */
271 		unsigned long	n;
272 
273 		if (((end - hdr) < sizeof (struct ar_hdr)) ||
274 		    (_elf_vm(elf, (size_t)(SARMAG),
275 		    sizeof (struct ar_hdr)) != OK_YES))
276 			return;
277 
278 		a = (struct ar_hdr *)hdr;
279 		mem = (char *)a + sizeof (struct ar_hdr);
280 		n = _elf_number(a->ar_size, &a->ar_size[ARSZ(ar_size)], 10);
281 		if ((end - mem < n) || (a->ar_name[0] != '/') ||
282 		    ((sz = n) != n)) {
283 			return;
284 		}
285 
286 		hdr = mem + sz;
287 		if (a->ar_name[1] == ' ') {
288 			elf->ed_arsym = mem;
289 			elf->ed_arsymsz = sz;
290 			elf->ed_arsymoff = (char *)a - base;
291 		} else if (a->ar_name[1] == '/' && a->ar_name[2] == ' ') {
292 			int	k;
293 
294 			if (_elf_vm(elf, (size_t)(mem - elf->ed_ident),
295 			    sz) != OK_YES)
296 				return;
297 			if (elf->ed_vm == 0) {
298 				char	*nmem;
299 				if ((nmem = malloc(sz)) == 0) {
300 					_elf_seterr(EMEM_ARSTR, errno);
301 					return;
302 				}
303 				(void) memcpy(nmem, mem, sz);
304 				elf->ed_myflags |= EDF_ASTRALLOC;
305 				mem = nmem;
306 			}
307 
308 			elf->ed_arstr = mem;
309 			elf->ed_arstrsz = sz;
310 			elf->ed_arstroff = (char *)a - base;
311 			for (k = 0; k < sz; k++) {
312 				if (*mem == '/')
313 					*mem = '\0';
314 				++mem;
315 			}
316 			*(mem - 1) = '\0';
317 		} else {
318 			return;
319 		}
320 		hdr += sz & 1;
321 	}
322 }
323