xref: /illumos-gate/usr/src/cmd/sgs/libelf/misc/nlist.c (revision bde334a8dbd66dfa70ce4d7fc9dcad6e1ae45fe4)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*	Copyright (c) 1988 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * Copyright (c) 1998 by Sun Microsystems, Inc.
28  * All rights reserved.
29  */
30 
31 #include "libelf.h"
32 #include <unistd.h>
33 #include <fcntl.h>
34 #include <string.h>
35 #include <nlist.h>
36 #include "syms.h"
37 #include "gelf.h"
38 
39 #undef n_name		/* This undef is to handle a #define in syms.h */
40 			/* which conflicts with the member nlist->n_name */
41 			/* as defined in nlist.h */
42 
43 
44 #define	SPACE 100		/* number of symbols read at a time */
45 #define	ISELF (strncmp(magic_buf, ELFMAG, SELFMAG) == 0)
46 
47 
48 int
49 end_elf_job(int fd, Elf * elfdes)
50 {
51 	(void) elf_end(elfdes);
52 	(void) close(fd);
53 	return (-1);
54 }
55 
56 
57 int
58 _elf_nlist(int fd, struct nlist * list)
59 {
60 	Elf	   *elfdes;	/* ELF descriptor */
61 	GElf_Ehdr  ehdr;	/* ELF Ehdr */
62 	GElf_Shdr  s_buf;	/* buffer storing section header */
63 	Elf_Data   *symdata;	/* buffer points to symbol table */
64 	Elf_Scn    *secidx = 0;	/* index of the section header table */
65 	GElf_Sym   sym;		/* buffer storing one symbol information */
66 	unsigned   strtab;	/* index of symbol name in string table */
67 	long	   count;	/* number of symbols */
68 	long	   ii;		/* loop control */
69 
70 	if (elf_version(EV_CURRENT) == EV_NONE) {
71 		(void) close(fd);
72 		return (-1);
73 	}
74 	elfdes = elf_begin(fd, ELF_C_READ, (Elf *)0);
75 	if (gelf_getehdr(elfdes, &ehdr) == 0)
76 		return (end_elf_job(fd, elfdes));
77 
78 	while ((secidx = elf_nextscn(elfdes, secidx)) != 0) {
79 		if ((gelf_getshdr(secidx, &s_buf)) == 0)
80 			return (end_elf_job(fd, elfdes));
81 		if (s_buf.sh_type != SHT_SYMTAB) /* not symbol table */
82 			continue;
83 		symdata = elf_getdata(secidx, (Elf_Data *)0);
84 		if (symdata == 0)
85 			return (end_elf_job(fd, elfdes));
86 		if (symdata->d_size == 0)
87 			break;
88 		strtab = s_buf.sh_link;
89 		count = symdata->d_size / s_buf.sh_entsize;
90 		for (ii = 1; ii < count; ++ii) {
91 			struct nlist *p;
92 			register char *name;
93 			/* LINTED */
94 			(void) gelf_getsym(symdata, (int)ii, &sym);
95 			name = elf_strptr(elfdes, strtab, (size_t)sym.st_name);
96 			if (name == 0)
97 				continue;
98 			for (p = list; p->n_name && p->n_name[0]; ++p) {
99 				if (strcmp(p->n_name, name))
100 					continue;
101 				p->n_value = (long)sym.st_value;
102 				p->n_type = GELF_ST_TYPE(sym.st_info);
103 				p->n_scnum = sym.st_shndx;
104 				break;
105 			}
106 		}
107 		break;
108 		/*
109 		 * Currently there is only one symbol table section
110 		 * in an object file, but this restriction may be
111 		 * relaxed in the future.
112 		 */
113 	}
114 	(void) elf_end(elfdes);
115 	(void) close(fd);
116 	return (0);
117 }
118 
119 int
120 nlist(const char * name, struct nlist * list)
121 {
122 	register struct nlist *p;
123 	char magic_buf[EI_NIDENT];
124 	int fd;
125 
126 	for (p = list; p->n_name && p->n_name[0]; p++) { /* n_name can be ptr */
127 		p->n_type = 0;
128 		p->n_value = 0L;
129 		p->n_scnum = 0;
130 		p->n_sclass = 0;
131 		p->n_numaux = 0;
132 	}
133 
134 	if ((fd = open(name, 0)) < 0)
135 		return (-1);
136 	if (read(fd, magic_buf, EI_NIDENT) == -1) {
137 		(void) close(fd);
138 		return (-1);
139 	}
140 
141 	if (lseek(fd, 0L, 0) == -1L) {	/* rewind to beginning of object file */
142 		(void) close(fd);
143 		return (-1);
144 	}
145 
146 #ifndef _LP64
147 	if (ISELF && (magic_buf[EI_CLASS] == ELFCLASS32))
148 #else
149 	if (ISELF)		/* 64-bit case handles both Elf32 and Elf64 */
150 #endif
151 		return (_elf_nlist(fd, list));
152 	else {
153 		(void) close(fd);
154 		return (-1);
155 	}
156 }
157