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/*
23 * Copyright (c) 1994, by Sun Microsytems, Inc.
24 */
25
26/*
27 * Functions to sync up library list with that of the run time linker
28 */
29
30#ifndef DEBUG
31#define	NDEBUG	1
32#endif
33
34#include <assert.h>
35
36#include "tnfctl_int.h"
37#include "kernel_int.h"
38#include "dbg.h"
39
40tnfctl_errcode_t
41tnfctl_check_libs(tnfctl_handle_t *hndl)
42{
43	tnfctl_errcode_t	prexstat;
44	enum event_op_t		dl_evt;
45	boolean_t		lmap_ok;
46
47	if (hndl->mode == KERNEL_MODE) {
48		prexstat = _tnfctl_refresh_kernel(hndl);
49		return (prexstat);
50	}
51
52	/* hndl refers to a process */
53
54	/* return value of lmap_ok, dl_evt ignored */
55	prexstat = _tnfctl_refresh_process(hndl, &lmap_ok, &dl_evt);
56	assert(lmap_ok == B_TRUE);
57	return (prexstat);
58}
59
60/*
61 * _tnfctl_lock_libs() locks the library list maintained in the prex
62 * handle against it changing by a dlopen or dlclose.
63 *
64 * This locking code is between the thread that owns the handle and
65 * another thread that may be doing a dlopen/dlclose.  We do not support
66 * the situation of having multiple threads operating on the same
67 * handle - in effect the code per tnfctl_handle can be thought of as
68 * being single-threaded - that is why we can check "hndl->in_objlist"
69 * without first obtaining a lock.  "in_objlist" is the re-entrancy
70 * protector on the lock i.e. we can call _tnfctl_lock_libs() safely even if
71 * this thread has the lock held.  The return value "release_lock" indicates
72 * whether the lock should be released or not.  It can be passed into
73 * _tnfctl_unlock_libs() which will do the right thing.
74 */
75
76tnfctl_errcode_t
77_tnfctl_lock_libs(tnfctl_handle_t *hndl, boolean_t *release_lock)
78{
79	/* this interface is only for INTERNAL_MODE clients */
80	assert(hndl->mode == INTERNAL_MODE);
81
82	if (hndl->in_objlist == B_TRUE) {
83		/*
84		 * already have _tnfctl_lmap_lock held which implies that
85		 * the library list has been sync'ed up
86		 */
87		*release_lock = B_FALSE;
88		return (TNFCTL_ERR_NONE);
89	}
90
91	/* lock is not currently held, so lock it */
92	mutex_lock(&_tnfctl_lmap_lock);
93	hndl->in_objlist = B_TRUE;
94
95	*release_lock = B_TRUE;
96	return (TNFCTL_ERR_NONE);
97}
98
99void
100_tnfctl_unlock_libs(tnfctl_handle_t *hndl, boolean_t release_lock)
101{
102	/* this interface is only for INTERNAL_MODE clients */
103	assert(hndl->mode == INTERNAL_MODE);
104
105	if (release_lock) {
106		hndl->in_objlist = B_FALSE;
107		mutex_unlock(&_tnfctl_lmap_lock);
108	}
109}
110
111/*
112 * _tnfctl_syn_lib_list() syncs up the library list maintained
113 * in the prex handle with the libraries in the process (if needed)
114 * NOTE: Assumes _tnfctl_lmap_lock is held.
115 *
116 */
117tnfctl_errcode_t
118_tnfctl_sync_lib_list(tnfctl_handle_t *hndl)
119{
120	tnfctl_errcode_t	prexstat = TNFCTL_ERR_NONE;
121	enum event_op_t		dl_evt;
122	boolean_t		lmap_ok;
123
124	/* this interface is only for INTERNAL_MODE clients */
125	assert(hndl->mode == INTERNAL_MODE);
126
127	/* lmap_lock held and in_objlist marked as B_TRUE */
128	if (_tnfctl_libs_changed == B_TRUE) {
129		prexstat = _tnfctl_refresh_process(hndl, &lmap_ok, &dl_evt);
130		if (prexstat) {
131			return (prexstat);
132		}
133	}
134	return (TNFCTL_ERR_NONE);
135}
136