xref: /illumos-gate/usr/src/cmd/sgs/libelf/common/ar.c (revision e616c49c963c6536f26b6d8888bc4bbb54716901)
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 /*
32  * Copyright (c) 2018, Joyent, Inc.
33  */
34 
35 #include <ar.h>
36 #include <stdlib.h>
37 #include <memory.h>
38 #include <errno.h>
39 #include <libelf.h>
40 #include "decl.h"
41 #include "msg.h"
42 #include "member.h"
43 
44 #define	MANGLE	'\177'
45 
46 
47 /*
48  * Archive processing
49  *	When processing an archive member, two things can happen
50  *	that are a little tricky.
51  *
52  * Sliding
53  *	Sliding support is left in for backward compatibility and for
54  *	support of Archives produced on other systems.  The bundled
55  *	ar(1) produces archives with all members on a 4 byte boundry,
56  *	so current archives should need no sliding.
57  *
58  *	Archive members that are only 2-byte aligned within the file will
59  *	be slid.  To reuse the file's memory image, the library slides an
60  *	archive member into its header to align the bytes.  This means
61  *	the header must be disposable.
62  *
63  * Header reuse
64  *	Because the library can trample the header, it must be preserved to
65  *	avoid restrictions on archive member reuse.  That is, if the member
66  *	header changes, the library may see garbage the next time it looks
67  *	at the header.  After extracting the original header, the library
68  *	appends it to the parents `ed_memlist' list, thus future lookups first
69  *	check this list to determine if a member has previously been processed
70  *	and whether sliding occured.
71  */
72 
73 
74 /*
75  * Size check
76  *	If the header is too small, the following generates a negative
77  *	subscript for x.x and fails to compile.
78  *
79  * The check is based on sizeof (Elf64) because that's always going
80  * to be at least as big as Elf32.
81  */
82 
83 struct	x
84 {
85 	char	x[sizeof (struct ar_hdr) - 3 * sizeof (Elf64) - 1];
86 };
87 
88 
89 
90 static const char	fmag[] = ARFMAG;
91 
92 
93 /*
94  * Convert a string starting at 'p' and ending at 'end' into
95  * an integer.  Base is the base of the number being converted
96  * (either 8 or 10).
97  *
98  * Returns the converted integer of the string being scaned.
99  */
100 unsigned long
101 _elf_number(char *p, char *end, int base)
102 {
103 	register unsigned	c;
104 	register unsigned long	n = 0;
105 
106 	while (p < end) {
107 		if ((c = *p - '0') >= base) {
108 			while (*p++ == ' ')
109 				if (p >= end)
110 					return (n);
111 			return (0);
112 		}
113 		n *= base;
114 		n += c;
115 		++p;
116 	}
117 	return (n);
118 }
119 
120 
121 /*
122  * Convert ar_hdr to Member
123  *	Converts ascii file representation to the binary memory values.
124  */
125 Member *
126 _elf_armem(Elf *elf, char *file, size_t fsz)
127 {
128 	register struct ar_hdr	*f = (struct ar_hdr *)file;
129 	register Member		*m;
130 	register Memlist	*l, * ol;
131 	register Memident	*i;
132 
133 	if (fsz < sizeof (struct ar_hdr)) {
134 		_elf_seterr(EFMT_ARHDRSZ, 0);
135 		return (0);
136 	}
137 
138 	/*
139 	 * Determine in this member has already been processed
140 	 */
141 	for (l = elf->ed_memlist, ol = l; l; ol = l, l = l->m_next)
142 		for (i = (Memident *)(l + 1); i < l->m_free; i++)
143 			if (i->m_offset == file)
144 				return (i->m_member);
145 
146 	if (f->ar_fmag[0] != fmag[0] || f->ar_fmag[1] != fmag[1]) {
147 		_elf_seterr(EFMT_ARFMAG, 0);
148 		return (0);
149 	}
150 
151 	/*
152 	 * Allocate a new member structure and assign it to the next free
153 	 * free memlist ident.
154 	 */
155 	if ((m = (Member *)malloc(sizeof (Member))) == 0) {
156 		_elf_seterr(EMEM_ARMEM, errno);
157 		return (0);
158 	}
159 	if ((elf->ed_memlist == 0) || (ol->m_free == ol->m_end)) {
160 		if ((l = (Memlist *)malloc(sizeof (Memlist) +
161 		    (sizeof (Memident) * MEMIDENTNO))) == 0) {
162 			_elf_seterr(EMEM_ARMEM, errno);
163 			free(m);
164 			return (0);
165 		}
166 		l->m_next = 0;
167 		l->m_free = (Memident *)(l + 1);
168 		l->m_end = (Memident *)((uintptr_t)l->m_free +
169 		    (sizeof (Memident) * MEMIDENTNO));
170 
171 		if (elf->ed_memlist == 0)
172 			elf->ed_memlist = l;
173 		else
174 			ol->m_next = l;
175 		ol = l;
176 	}
177 	ol->m_free->m_offset = file;
178 	ol->m_free->m_member = m;
179 	ol->m_free++;
180 
181 	m->m_err = 0;
182 	(void) memcpy(m->m_name, f->ar_name, ARSZ(ar_name));
183 	m->m_name[ARSZ(ar_name)] = '\0';
184 	m->m_hdr.ar_name = m->m_name;
185 	(void) memcpy(m->m_raw, f->ar_name, ARSZ(ar_name));
186 	m->m_raw[ARSZ(ar_name)] = '\0';
187 	m->m_hdr.ar_rawname = m->m_raw;
188 	m->m_slide = 0;
189 
190 	/*
191 	 * Classify file name.
192 	 * If a name error occurs, delay until getarhdr().
193 	 */
194 
195 	if (f->ar_name[0] != '/') {	/* regular name */
196 		register char	*p;
197 
198 		p = &m->m_name[sizeof (m->m_name)];
199 		while (*--p != '/')
200 			if (p <= m->m_name)
201 				break;
202 		*p = '\0';
203 	} else if (f->ar_name[1] >= '0' && f->ar_name[1] <= '9') { /* strtab */
204 		register unsigned long	j;
205 
206 		j = _elf_number(&f->ar_name[1],
207 		    &f->ar_name[ARSZ(ar_name)], 10);
208 		if (j < elf->ed_arstrsz)
209 			m->m_hdr.ar_name = elf->ed_arstr + j;
210 		else {
211 			m->m_hdr.ar_name = 0;
212 			/*LINTED*/ /* MSG_INTL(EFMT_ARSTRNM) */
213 			m->m_err = (int)EFMT_ARSTRNM;
214 		}
215 	} else if (f->ar_name[1] == ' ')			/* "/" */
216 		m->m_name[1] = '\0';
217 	else if (f->ar_name[1] == '/' && f->ar_name[2] == ' ')	/* "//" */
218 		m->m_name[2] = '\0';
219 	else if (f->ar_name[1] == 'S' && f->ar_name[2] == 'Y' &&
220 	    f->ar_name[3] == 'M' && f->ar_name[4] == '6' &&
221 	    f->ar_name[5] == '4' && f->ar_name[6] == '/' &&
222 	    f->ar_name[7] == ' ')				/* "/SYM64/" */
223 		m->m_name[7] = '\0';
224 	else {							/* "/?" */
225 		m->m_hdr.ar_name = 0;
226 		/*LINTED*/ /* MSG_INTL(EFMT_ARUNKNM) */
227 		m->m_err = (int)EFMT_ARUNKNM;
228 	}
229 
230 	m->m_hdr.ar_date = (time_t)_elf_number(f->ar_date,
231 	    &f->ar_date[ARSZ(ar_date)], 10);
232 	/* LINTED */
233 	m->m_hdr.ar_uid = (uid_t)_elf_number(f->ar_uid,
234 	    &f->ar_uid[ARSZ(ar_uid)], 10);
235 	/* LINTED */
236 	m->m_hdr.ar_gid = (gid_t)_elf_number(f->ar_gid,
237 	    &f->ar_gid[ARSZ(ar_gid)], 10);
238 	/* LINTED */
239 	m->m_hdr.ar_mode = (mode_t)_elf_number(f->ar_mode,
240 	    &f->ar_mode[ARSZ(ar_mode)], 8);
241 	m->m_hdr.ar_size = (off_t)_elf_number(f->ar_size,
242 	    &f->ar_size[ARSZ(ar_size)], 10);
243 
244 	return (m);
245 }
246 
247 
248 /*
249  * Initial archive processing
250  *	An archive may have two special members.
251  *
252  *	A symbol table, named / or /SYM64/, must be first if it is present.
253  *	Both forms use the same layout differing in the width of the
254  *	integer type used (32 or 64-bit respectively).
255  *
256  *	A long name string table, named //, must precede all "normal"
257  *	members. This string table is used to hold the names of archive
258  *	members with names that are longer than 15 characters. It should not
259  *	be confused with the string table found at the end of the symbol
260  *	table, which is used to hold symbol names.
261  *
262  *	This code "peeks" at headers but doesn't change them.
263  *	Later processing wants original headers.
264  *
265  *	String table is converted, changing '/' name terminators
266  *	to nulls.  The last byte in the string table, which should
267  *	be '\n', is set to nil, guaranteeing null termination.  That
268  *	byte should be '\n', but this code doesn't check.
269  *
270  *	The symbol table conversion is delayed until needed.
271  */
272 void
273 _elf_arinit(Elf * elf)
274 {
275 	char				*base = elf->ed_ident;
276 	register char			*end = base + elf->ed_fsz;
277 	register struct ar_hdr		*a;
278 	register char			*hdr = base + SARMAG;
279 	register char			*mem;
280 	int				j;
281 	size_t				sz = SARMAG;
282 
283 	elf->ed_status = ES_COOKED;
284 	elf->ed_nextoff = SARMAG;
285 	for (j = 0; j < 2; ++j)	 {	/* 2 special members */
286 		unsigned long	n;
287 
288 		if (((end - hdr) < sizeof (struct ar_hdr)) ||
289 		    (_elf_vm(elf, (size_t)(SARMAG),
290 		    sizeof (struct ar_hdr)) != OK_YES))
291 			return;
292 
293 		a = (struct ar_hdr *)hdr;
294 		mem = (char *)a + sizeof (struct ar_hdr);
295 		n = _elf_number(a->ar_size, &a->ar_size[ARSZ(ar_size)], 10);
296 		if ((end - mem < n) || (a->ar_name[0] != '/') ||
297 		    ((sz = n) != n)) {
298 			return;
299 		}
300 
301 		hdr = mem + sz;
302 		if (a->ar_name[1] == ' ') {	/* 32-bit symbol table */
303 			elf->ed_arsym = mem;
304 			elf->ed_arsymsz = sz;
305 			elf->ed_arsymoff = (char *)a - base;
306 		} else if (a->ar_name[1] == '/' && a->ar_name[2] == ' ') {
307 						/* Long name string table */
308 			int	k;
309 
310 			if (_elf_vm(elf, (size_t)(mem - elf->ed_ident),
311 			    sz) != OK_YES)
312 				return;
313 			if (elf->ed_vm == 0) {
314 				char	*nmem;
315 				if ((nmem = malloc(sz)) == 0) {
316 					_elf_seterr(EMEM_ARSTR, errno);
317 					return;
318 				}
319 				(void) memcpy(nmem, mem, sz);
320 				elf->ed_myflags |= EDF_ASTRALLOC;
321 				mem = nmem;
322 			}
323 
324 			elf->ed_arstr = mem;
325 			elf->ed_arstrsz = sz;
326 			elf->ed_arstroff = (char *)a - base;
327 			for (k = 0; k < sz; k++) {
328 				if (*mem == '/')
329 					*mem = '\0';
330 				++mem;
331 			}
332 			*(mem - 1) = '\0';
333 		} else if (a->ar_name[1] == 'S' && a->ar_name[2] == 'Y' &&
334 		    a->ar_name[3] == 'M' && a->ar_name[4] == '6' &&
335 		    a->ar_name[5] == '4' && a->ar_name[6] == '/' &&
336 		    a->ar_name[7] == ' ') {
337 						/* 64-bit symbol table */
338 			elf->ed_arsym = mem;
339 			elf->ed_arsymsz = sz;
340 			elf->ed_arsymoff = (char *)a - base;
341 			elf->ed_myflags |= EDF_ARSYM64;
342 		} else {
343 			return;
344 		}
345 		hdr += sz & 1;
346 	}
347 }
348