xref: /illumos-gate/usr/src/uts/common/c2/audit_mem.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
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 (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 
25 #include <sys/param.h>
26 #include <sys/types.h>
27 #include <sys/kmem.h>
28 #include <sys/t_lock.h>
29 #include <sys/thread.h>
30 #include <sys/systm.h>
31 #include <c2/audit.h>
32 #include <c2/audit_kernel.h>
33 #include <c2/audit_record.h>
34 
35 static kmem_cache_t *au_buf_cache;
36 
37 /*
38  * au_buff_t and token_t are equivalent (see audit_record.h).  Don't
39  * confuse this token_t with the one that is defined for userspace
40  * in the same header file.
41  */
42 
43 /*
44  * Function: au_get_buff
45  * args:
46  */
47 struct au_buff *
48 au_get_buff(void)
49 {
50 	au_buff_t *buffer;
51 	t_audit_data_t *tad = U2A(u);
52 
53 	ASSERT(tad);
54 
55 	/*
56 	 * If asynchronous (interrupt) thread, then we can't sleep
57 	 * (the tad ERRJMP flag is set at the start of async processing).
58 	 */
59 	if (tad->tad_ctrl & TAD_ERRJMP) {
60 		buffer = kmem_cache_alloc(au_buf_cache, KM_NOSLEEP);
61 		if (buffer == NULL) {
62 			/* return to top of stack & report an error */
63 			ASSERT(tad->tad_errjmp);
64 			longjmp(tad->tad_errjmp);
65 		}
66 	} else {
67 		buffer = kmem_cache_alloc(au_buf_cache, KM_SLEEP);
68 	}
69 	/* Never gets here when buffer == NULL */
70 	bzero(buffer, sizeof (*buffer));
71 	return (buffer);
72 }
73 
74 /*
75  * Function: au_free_rec
76  * args:
77  *	au_buff_t *buf;		start of the record chain
78  */
79 void
80 au_free_rec(au_buff_t *buf)
81 {
82 	au_buff_t *next;
83 	t_audit_data_t *tad = U2A(u);
84 
85 	ASSERT(tad);
86 
87 	/*
88 	 * If asynchronous (interrupt) thread, schedule the release
89 	 * (the tad ERRJMP flag is set at the start of async processing).
90 	 */
91 	if (tad->tad_ctrl & TAD_ERRJMP) {
92 		/* Discard async events via softcall. */
93 		softcall(audit_async_discard_backend, buf);
94 	}
95 
96 	while (buf != NULL) {
97 		next = buf->next_buf;
98 		kmem_cache_free(au_buf_cache, buf);
99 		buf = next;
100 	}
101 }
102 
103 /*
104  * Backend routine to discard an async event. Invoked from softcall.
105  * (Note: the freeing of memory for the event can't be done safely in high
106  * interrupt context due to the chance of sleeping on an adaptive mutex.
107  * Hence the softcall.)
108  */
109 void
110 audit_async_discard_backend(void *addr)
111 {
112 	au_toss_token(addr);
113 }
114 
115 /*
116  * Function: au_append_rec
117  * args:
118  *	au_buff_t *rec;		start of the record chain
119  *	au_buff_t *buf;		buffer to append
120  *	int        pack;	AU_PACK/1 - pack data, AU_LINK/0 - link buffer
121  */
122 int
123 au_append_rec(au_buff_t *rec, au_buff_t *buf, int pack)
124 {
125 	if (!rec)
126 		return (-1);
127 
128 	while (rec->next_buf)
129 		rec = rec->next_buf;
130 	if (((int)(rec->len + buf->len) <= AU_BUFSIZE) && pack) {
131 		bcopy(buf->buf, (char *)(rec->buf + rec->len),
132 		    (uint_t)buf->len);
133 		rec->len += buf->len;
134 		rec->next_buf = buf->next_buf;
135 		kmem_cache_free(au_buf_cache, buf);
136 	} else {
137 		rec->next_buf = buf;
138 	}
139 	return (0);
140 }
141 
142 /*
143  * Function: au_append_buf
144  * args:
145  *	char *data;		data buffer to append
146  *	int len;		size of data to append
147  *	au_buff_t *buf;		buffer to append to
148  */
149 int
150 au_append_buf(const char *data, int len, au_buff_t *buf)
151 {
152 	au_buff_t *new_buf;
153 	int	new_len;
154 
155 	while (buf->next_buf != NULL)
156 		buf = buf->next_buf;
157 
158 	new_len = (uint_t)(buf->len + len) > AU_BUFSIZE ?
159 	    AU_BUFSIZE - buf->len : len;
160 	bcopy(data, (buf->buf + buf->len), (uint_t)new_len);
161 	buf->len += (uchar_t)new_len;
162 	len -= new_len;
163 
164 	while (len > 0) {
165 		data += new_len;
166 		if ((new_buf = au_get_buff()) == NULL) {
167 			return (-1);
168 		}
169 		buf->next_buf = new_buf;
170 		buf = new_buf;
171 		new_len = len > AU_BUFSIZE ? AU_BUFSIZE : len;
172 		bcopy(data, buf->buf, (uint_t)new_len);
173 		buf->len = (uchar_t)new_len;
174 		len -= new_len;
175 	}
176 	return (0);
177 }
178 
179 void
180 au_mem_init()
181 {
182 	au_buf_cache = kmem_cache_create("audit_buffer",
183 	    sizeof (au_buff_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
184 }
185