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 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 #include "misc.h"
29
30 #define UMEM_OBJNAME "libumem.so"
31
32 int umem_debug_level = 0;
33 int umem_is_standalone = 0;
34
35 /*ARGSUSED*/
36 int
umem_debug(uintptr_t addr,uint_t flags,int argc,const mdb_arg_t * argv)37 umem_debug(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
38 {
39 umem_debug_level ^= 1;
40
41 mdb_printf("umem: debugging is now %s\n",
42 umem_debug_level ? "on" : "off");
43
44 return (DCMD_OK);
45 }
46
47 /*
48 * To further confuse the issue, this dmod can run against either
49 * libumem.so.1 *or* the libstandumem.so linked into kmdb(1M). To figure
50 * out which one we are working against, we look up "umem_alloc" in both
51 * libumem.so and the executable.
52 *
53 * A further wrinkle is that libumem.so may not yet be loaded into the
54 * process' address space. That can lead to either the lookup failing, or
55 * being unable to read from the data segment. We treat either case as
56 * an error.
57 */
58 int
umem_set_standalone(void)59 umem_set_standalone(void)
60 {
61 GElf_Sym sym;
62 int ready;
63
64 if (mdb_lookup_by_obj(UMEM_OBJNAME, "umem_alloc", &sym) == 0)
65 umem_is_standalone = 0;
66 else if (mdb_lookup_by_obj(MDB_OBJ_EXEC, "umem_alloc", &sym) == 0)
67 umem_is_standalone = 1;
68 else
69 return (-1);
70
71 /*
72 * now that we know where things should be, make sure we can actually
73 * read things out.
74 */
75 if (umem_readvar(&ready, "umem_ready") == -1)
76 return (-1);
77 return (0);
78 }
79
80 ssize_t
umem_lookup_by_name(const char * name,GElf_Sym * sym)81 umem_lookup_by_name(const char *name, GElf_Sym *sym)
82 {
83 return (mdb_lookup_by_obj((umem_is_standalone ? MDB_OBJ_EXEC :
84 UMEM_OBJNAME), name, sym));
85 }
86
87 /* This is like mdb_readvar, only for libumem.so's symbols */
88 ssize_t
umem_readvar(void * buf,const char * name)89 umem_readvar(void *buf, const char *name)
90 {
91 GElf_Sym sym;
92
93 if (umem_lookup_by_name(name, &sym))
94 return (-1);
95
96 if (mdb_vread(buf, sym.st_size, (uintptr_t)sym.st_value)
97 == sym.st_size)
98 return ((ssize_t)sym.st_size);
99
100 return (-1);
101 }
102
103 int
is_umem_sym(const char * sym,const char * prefix)104 is_umem_sym(const char *sym, const char *prefix)
105 {
106 char *tick_p = strrchr(sym, '`');
107
108 return (strncmp(sym, "libumem", 7) == 0 && tick_p != NULL &&
109 strncmp(tick_p + 1, prefix, strlen(prefix)) == 0);
110 }
111