xref: /illumos-gate/usr/src/cmd/mdb/common/kmdb/kmdb_dl.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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 #include <dlfcn.h>
28 #include <sys/modctl.h>
29 #include <sys/kobj.h>
30 
31 #include <kmdb/kmdb_module.h>
32 #include <mdb/mdb_debug.h>
33 #include <mdb/mdb_gelf.h>
34 #include <mdb/mdb_string.h>
35 #include <mdb/mdb.h>
36 
37 /*
38  * kmdb libdl-style interface for the manipulation of dmods.
39  */
40 
41 static char *dl_errstr;
42 
43 static kmdb_modctl_t *
44 dl_name2ctl(const char *pathname)
45 {
46 	mdb_var_t *v;
47 
48 	if ((v = mdb_nv_lookup(&mdb.m_dmodctl, strbasename(pathname))) ==
49 	    NULL)
50 		return (NULL);
51 
52 	return ((kmdb_modctl_t *)MDB_NV_COOKIE(v));
53 }
54 
55 /*ARGSUSED*/
56 void *
57 dlmopen(Lmid_t lmid, const char *pathname, int mode)
58 {
59 	kmdb_modctl_t *kmc;
60 
61 	if ((kmc = dl_name2ctl(pathname)) == NULL) {
62 		dl_errstr = "unregistered module";
63 		return (NULL);
64 	}
65 
66 	kmc->kmc_dlrefcnt++;
67 
68 	dl_errstr = NULL;
69 
70 	return (kmc);
71 }
72 
73 int
74 dlclose(void *dlp)
75 {
76 	kmdb_modctl_t *kmc = dlp;
77 
78 	dl_errstr = NULL;
79 
80 	ASSERT(kmc->kmc_dlrefcnt > 0);
81 	if (--kmc->kmc_dlrefcnt > 0)
82 		return (0);
83 
84 	return (0);
85 }
86 
87 char *
88 dlerror(void)
89 {
90 	char *str = dl_errstr;
91 
92 	dl_errstr = NULL;
93 
94 	return (str);
95 }
96 
97 static void *
98 dl_findsym(kmdb_modctl_t *kmc, const char *name)
99 {
100 	GElf_Sym sym;
101 	uint_t symid;
102 
103 	if (mdb_gelf_symtab_lookup_by_name(kmc->kmc_symtab, name, &sym,
104 	    &symid) < 0)
105 		return (NULL);
106 
107 	return ((void *)(uintptr_t)sym.st_value);
108 }
109 
110 /*ARGSUSED*/
111 void *
112 dlsym(void *dlp, const char *name)
113 {
114 	kmdb_modctl_t *kmc = dlp;
115 	mdb_var_t *v;
116 	void *addr;
117 
118 	switch ((uintptr_t)dlp) {
119 	case (uintptr_t)RTLD_NEXT:
120 		mdb_nv_rewind(&mdb.m_dmodctl);
121 		while ((v = mdb_nv_advance(&mdb.m_dmodctl)) != NULL) {
122 			if ((addr = dl_findsym(MDB_NV_COOKIE(v), name)) != NULL)
123 				break;
124 		}
125 		break;
126 
127 	case (uintptr_t)RTLD_DEFAULT:
128 	case (uintptr_t)RTLD_SELF:
129 		dl_errstr = "invalid handle";
130 		return (NULL);
131 
132 	default:
133 		addr = dl_findsym(kmc, name);
134 	}
135 
136 	dl_errstr = (addr == NULL) ? "symbol not found" : NULL;
137 
138 	return (addr);
139 }
140 
141 #pragma weak _dladdr1 = dladdr1
142 /*ARGSUSED*/
143 int
144 dladdr1(void *address, Dl_info *dlip, void **info, int flags)
145 {
146 	/*
147 	 * umem uses this for debugging information.  We'll pretend to fail.
148 	 */
149 
150 	return (0);
151 }
152