xref: /netbsd-src/lib/libc/gen/nlist.c (revision cda4f8f6ee55684e8d311b86c99ea59191e6b74f)
1 /*
2  * Copyright (c) 1989 The Regents of the University of California.
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, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 /*static char sccsid[] = "from: @(#)nlist.c	5.8 (Berkeley) 2/23/91";*/
36 static char rcsid[] = "$Id: nlist.c,v 1.2 1993/07/30 08:22:55 mycroft Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 #include <sys/types.h>
40 #include <sys/file.h>
41 #include <a.out.h>
42 #include <stdio.h>
43 #include <string.h>
44 #include <unistd.h>
45 
46 typedef struct nlist NLIST;
47 #define	_strx	n_un.n_strx
48 #define	_name	n_un.n_name
49 #define	ISVALID(p)	(p->_name && p->_name[0])
50 
51 int
52 nlist(name, list)
53 	const char *name;
54 	NLIST *list;
55 {
56 	register NLIST *p, *s;
57 	struct exec ebuf;
58 	FILE *fstr, *fsym;
59 	NLIST nbuf;
60 	off_t strings_offset, symbol_offset, symbol_size, lseek();
61 	int entries, len, maxlen;
62 	char sbuf[256];
63 
64 	entries = -1;
65 
66 	if (!(fsym = fopen(name, "r")))
67 		return(-1);
68 	if (fread((char *)&ebuf, sizeof(struct exec), 1, fsym) != 1 ||
69 	    N_BADMAG(ebuf))
70 		goto done1;
71 
72 	symbol_offset = N_SYMOFF(ebuf);
73 	symbol_size = ebuf.a_syms;
74 	strings_offset = symbol_offset + symbol_size;
75 	if (fseek(fsym, symbol_offset, SEEK_SET))
76 		goto done1;
77 
78 	if (!(fstr = fopen(name, "r")))
79 		goto done1;
80 
81 	/*
82 	 * clean out any left-over information for all valid entries.
83 	 * Type and value defined to be 0 if not found; historical
84 	 * versions cleared other and desc as well.  Also figure out
85 	 * the largest string length so don't read any more of the
86 	 * string table than we have to.
87 	 */
88 	for (p = list, entries = maxlen = 0; ISVALID(p); ++p, ++entries) {
89 		p->n_type = 0;
90 		p->n_other = 0;
91 		p->n_desc = 0;
92 		p->n_value = 0;
93 		if ((len = strlen(p->_name)) > maxlen)
94 			maxlen = len;
95 	}
96 	if (++maxlen > sizeof(sbuf)) {		/* for the NULL */
97 		(void)fprintf(stderr, "nlist: symbol too large.\n");
98 		entries = -1;
99 		goto done2;
100 	}
101 
102 	for (s = &nbuf; symbol_size; symbol_size -= sizeof(NLIST)) {
103 		if (fread((char *)s, sizeof(NLIST), 1, fsym) != 1)
104 			goto done2;
105 		if (!s->_strx || s->n_type&N_STAB)
106 			continue;
107 		if (fseek(fstr, strings_offset + s->_strx, SEEK_SET))
108 			goto done2;
109 		(void)fread(sbuf, sizeof(sbuf[0]), maxlen, fstr);
110 		for (p = list; ISVALID(p); p++)
111 			if (!strcmp(p->_name, sbuf)) {
112 				p->n_value = s->n_value;
113 				p->n_type = s->n_type;
114 				p->n_desc = s->n_desc;
115 				p->n_other = s->n_other;
116 				if (!--entries)
117 					goto done2;
118 			}
119 	}
120 done2:	(void)fclose(fstr);
121 done1:	(void)fclose(fsym);
122 	return(entries);
123 }
124