xref: /titanic_41/usr/src/cmd/sgs/libelf/common/ar.c (revision 49d3bc91e27cd871b950d56c01398fa2f2e12ab4)
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 (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 /*
27  *	Copyright (c) 1988 AT&T
28  *	  All Rights Reserved
29  */
30 
31 #include <ar.h>
32 #include <stdlib.h>
33 #include <memory.h>
34 #include <errno.h>
35 #include <libelf.h>
36 #include "decl.h"
37 #include "msg.h"
38 #include "member.h"
39 
40 #define	MANGLE	'\177'
41 
42 
43 /*
44  * Archive processing
45  *	When processing an archive member, two things can happen
46  *	that are a little tricky.
47  *
48  * Sliding
49  *	Sliding support is left in for backward compatibility and for
50  *	support of Archives produced on other systems.  The bundled
51  *	ar(1) produces archives with all members on a 4 byte boundry,
52  *	so current archives should need no sliding.
53  *
54  *	Archive members that are only 2-byte aligned within the file will
55  *	be slid.  To reuse the file's memory image, the library slides an
56  *	archive member into its header to align the bytes.  This means
57  *	the header must be disposable.
58  *
59  * Header reuse
60  *	Because the library can trample the header, it must be preserved to
61  *	avoid restrictions on archive member reuse.  That is, if the member
62  *	header changes, the library may see garbage the next time it looks
63  *	at the header.  After extracting the original header, the library
64  *	appends it to the parents `ed_memlist' list, thus future lookups first
65  *	check this list to determine if a member has previously been processed
66  *	and whether sliding occured.
67  */
68 
69 
70 /*
71  * Size check
72  *	If the header is too small, the following generates a negative
73  *	subscript for x.x and fails to compile.
74  *
75  * The check is based on sizeof (Elf64) because that's always going
76  * to be at least as big as Elf32.
77  */
78 
79 struct	x
80 {
81 	char	x[sizeof (struct ar_hdr) - 3 * sizeof (Elf64) - 1];
82 };
83 
84 
85 
86 static const char	fmag[] = ARFMAG;
87 
88 
89 /*
90  * Convert a string starting at 'p' and ending at 'end' into
91  * an integer.  Base is the base of the number being converted
92  * (either 8 or 10).
93  *
94  * Returns the converted integer of the string being scaned.
95  */
96 unsigned long
97 _elf_number(char *p, char *end, int base)
98 {
99 	register unsigned	c;
100 	register unsigned long	n = 0;
101 
102 	while (p < end) {
103 		if ((c = *p - '0') >= base) {
104 			while (*p++ == ' ')
105 				if (p >= end)
106 					return (n);
107 			return (0);
108 		}
109 		n *= base;
110 		n += c;
111 		++p;
112 	}
113 	return (n);
114 }
115 
116 
117 /*
118  * Convert ar_hdr to Member
119  *	Converts ascii file representation to the binary memory values.
120  */
121 Member *
122 _elf_armem(Elf *elf, char *file, size_t fsz)
123 {
124 	register struct ar_hdr	*f = (struct ar_hdr *)file;
125 	register Member		*m;
126 	register Memlist	*l, * ol;
127 	register Memident	*i;
128 
129 	if (fsz < sizeof (struct ar_hdr)) {
130 		_elf_seterr(EFMT_ARHDRSZ, 0);
131 		return (0);
132 	}
133 
134 	/*
135 	 * Determine in this member has already been processed
136 	 */
137 	for (l = elf->ed_memlist, ol = l; l; ol = l, l = l->m_next)
138 		for (i = (Memident *)(l + 1); i < l->m_free; i++)
139 			if (i->m_offset == file)
140 				return (i->m_member);
141 
142 	if (f->ar_fmag[0] != fmag[0] || f->ar_fmag[1] != fmag[1]) {
143 		_elf_seterr(EFMT_ARFMAG, 0);
144 		return (0);
145 	}
146 
147 	/*
148 	 * Allocate a new member structure and assign it to the next free
149 	 * free memlist ident.
150 	 */
151 	if ((m = (Member *)malloc(sizeof (Member))) == 0) {
152 		_elf_seterr(EMEM_ARMEM, errno);
153 		return (0);
154 	}
155 	if ((elf->ed_memlist == 0) || (ol->m_free == ol->m_end)) {
156 		if ((l = (Memlist *)malloc(sizeof (Memlist) +
157 		    (sizeof (Memident) * MEMIDENTNO))) == 0) {
158 			_elf_seterr(EMEM_ARMEM, errno);
159 			return (0);
160 		}
161 		l->m_next = 0;
162 		l->m_free = (Memident *)(l + 1);
163 		l->m_end = (Memident *)((uintptr_t)l->m_free +
164 		    (sizeof (Memident) * MEMIDENTNO));
165 
166 		if (elf->ed_memlist == 0)
167 			elf->ed_memlist = l;
168 		else
169 			ol->m_next = l;
170 		ol = l;
171 	}
172 	ol->m_free->m_offset = file;
173 	ol->m_free->m_member = m;
174 	ol->m_free++;
175 
176 	m->m_err = 0;
177 	(void) memcpy(m->m_name, f->ar_name, ARSZ(ar_name));
178 	m->m_name[ARSZ(ar_name)] = '\0';
179 	m->m_hdr.ar_name = m->m_name;
180 	(void) memcpy(m->m_raw, f->ar_name, ARSZ(ar_name));
181 	m->m_raw[ARSZ(ar_name)] = '\0';
182 	m->m_hdr.ar_rawname = m->m_raw;
183 	m->m_slide = 0;
184 
185 	/*
186 	 * Classify file name.
187 	 * If a name error occurs, delay until getarhdr().
188 	 */
189 
190 	if (f->ar_name[0] != '/') {	/* regular name */
191 		register char	*p;
192 
193 		p = &m->m_name[sizeof (m->m_name)];
194 		while (*--p != '/')
195 			if (p <= m->m_name)
196 				break;
197 		*p = '\0';
198 	} else if (f->ar_name[1] >= '0' && f->ar_name[1] <= '9') { /* strtab */
199 		register unsigned long	j;
200 
201 		j = _elf_number(&f->ar_name[1],
202 		    &f->ar_name[ARSZ(ar_name)], 10);
203 		if (j < elf->ed_arstrsz)
204 			m->m_hdr.ar_name = elf->ed_arstr + j;
205 		else {
206 			m->m_hdr.ar_name = 0;
207 			/*LINTED*/ /* MSG_INTL(EFMT_ARSTRNM) */
208 			m->m_err = (int)EFMT_ARSTRNM;
209 		}
210 	} else if (f->ar_name[1] == ' ')			/* "/" */
211 		m->m_name[1] = '\0';
212 	else if (f->ar_name[1] == '/' && f->ar_name[2] == ' ')	/* "//" */
213 		m->m_name[2] = '\0';
214 	else if (f->ar_name[1] == 'S' && f->ar_name[2] == 'Y' &&
215 	    f->ar_name[3] == 'M' && f->ar_name[4] == '6' &&
216 	    f->ar_name[5] == '4' && f->ar_name[6] == '/' &&
217 	    f->ar_name[7] == ' ')				/* "/SYM64/" */
218 		m->m_name[7] = '\0';
219 	else {							/* "/?" */
220 		m->m_hdr.ar_name = 0;
221 		/*LINTED*/ /* MSG_INTL(EFMT_ARUNKNM) */
222 		m->m_err = (int)EFMT_ARUNKNM;
223 	}
224 
225 	m->m_hdr.ar_date = (time_t)_elf_number(f->ar_date,
226 	    &f->ar_date[ARSZ(ar_date)], 10);
227 	/* LINTED */
228 	m->m_hdr.ar_uid = (uid_t)_elf_number(f->ar_uid,
229 	    &f->ar_uid[ARSZ(ar_uid)], 10);
230 	/* LINTED */
231 	m->m_hdr.ar_gid = (gid_t)_elf_number(f->ar_gid,
232 	    &f->ar_gid[ARSZ(ar_gid)], 10);
233 	/* LINTED */
234 	m->m_hdr.ar_mode = (mode_t)_elf_number(f->ar_mode,
235 	    &f->ar_mode[ARSZ(ar_mode)], 8);
236 	m->m_hdr.ar_size = (off_t)_elf_number(f->ar_size,
237 	    &f->ar_size[ARSZ(ar_size)], 10);
238 
239 	return (m);
240 }
241 
242 
243 /*
244  * Initial archive processing
245  *	An archive may have two special members.
246  *
247  *	A symbol table, named / or /SYM64/, must be first if it is present.
248  *	Both forms use the same layout differing in the width of the
249  *	integer type used (32 or 64-bit respectively).
250  *
251  *	A long name string table, named //, must precede all "normal"
252  *	members. This string table is used to hold the names of archive
253  *	members with names that are longer than 15 characters. It should not
254  *	be confused with the string table found at the end of the symbol
255  *	table, which is used to hold symbol names.
256  *
257  *	This code "peeks" at headers but doesn't change them.
258  *	Later processing wants original headers.
259  *
260  *	String table is converted, changing '/' name terminators
261  *	to nulls.  The last byte in the string table, which should
262  *	be '\n', is set to nil, guaranteeing null termination.  That
263  *	byte should be '\n', but this code doesn't check.
264  *
265  *	The symbol table conversion is delayed until needed.
266  */
267 void
268 _elf_arinit(Elf * elf)
269 {
270 	char				*base = elf->ed_ident;
271 	register char			*end = base + elf->ed_fsz;
272 	register struct ar_hdr		*a;
273 	register char			*hdr = base + SARMAG;
274 	register char			*mem;
275 	int				j;
276 	size_t				sz = SARMAG;
277 
278 	elf->ed_status = ES_COOKED;
279 	elf->ed_nextoff = SARMAG;
280 	for (j = 0; j < 2; ++j)	 {	/* 2 special members */
281 		unsigned long	n;
282 
283 		if (((end - hdr) < sizeof (struct ar_hdr)) ||
284 		    (_elf_vm(elf, (size_t)(SARMAG),
285 		    sizeof (struct ar_hdr)) != OK_YES))
286 			return;
287 
288 		a = (struct ar_hdr *)hdr;
289 		mem = (char *)a + sizeof (struct ar_hdr);
290 		n = _elf_number(a->ar_size, &a->ar_size[ARSZ(ar_size)], 10);
291 		if ((end - mem < n) || (a->ar_name[0] != '/') ||
292 		    ((sz = n) != n)) {
293 			return;
294 		}
295 
296 		hdr = mem + sz;
297 		if (a->ar_name[1] == ' ') {	/* 32-bit symbol table */
298 			elf->ed_arsym = mem;
299 			elf->ed_arsymsz = sz;
300 			elf->ed_arsymoff = (char *)a - base;
301 		} else if (a->ar_name[1] == '/' && a->ar_name[2] == ' ') {
302 						/* Long name string table */
303 			int	k;
304 
305 			if (_elf_vm(elf, (size_t)(mem - elf->ed_ident),
306 			    sz) != OK_YES)
307 				return;
308 			if (elf->ed_vm == 0) {
309 				char	*nmem;
310 				if ((nmem = malloc(sz)) == 0) {
311 					_elf_seterr(EMEM_ARSTR, errno);
312 					return;
313 				}
314 				(void) memcpy(nmem, mem, sz);
315 				elf->ed_myflags |= EDF_ASTRALLOC;
316 				mem = nmem;
317 			}
318 
319 			elf->ed_arstr = mem;
320 			elf->ed_arstrsz = sz;
321 			elf->ed_arstroff = (char *)a - base;
322 			for (k = 0; k < sz; k++) {
323 				if (*mem == '/')
324 					*mem = '\0';
325 				++mem;
326 			}
327 			*(mem - 1) = '\0';
328 		} else if (a->ar_name[1] == 'S' && a->ar_name[2] == 'Y' &&
329 		    a->ar_name[3] == 'M' && a->ar_name[4] == '6' &&
330 		    a->ar_name[5] == '4' && a->ar_name[6] == '/' &&
331 		    a->ar_name[7] == ' ') {
332 						/* 64-bit symbol table */
333 			elf->ed_arsym = mem;
334 			elf->ed_arsymsz = sz;
335 			elf->ed_arsymoff = (char *)a - base;
336 			elf->ed_myflags |= EDF_ARSYM64;
337 		} else {
338 			return;
339 		}
340 		hdr += sz & 1;
341 	}
342 }
343