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