common/c2/audit_mem.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/kmem.h>
#include <sys/t_lock.h>
#include <sys/thread.h>
#include <sys/systm.h>
#include <c2/audit.h>
#include <c2/audit_kernel.h>
#include <c2/audit_record.h>

static kmem_cache_t *au_buf_cache;

/*
 * au_buff_t and token_t are equivalent (see audit_record.h).  Don't
 * confuse this token_t with the one that is defined for userspace
 * in the same header file.
 */

/*
 * Function: au_get_buff
 * args:
 */
struct au_buff *
au_get_buff(void)
{
    au_buff_t *buffer;
    t_audit_data_t *tad = U2A(u);

    ASSERT(tad);

    /*
     * If asynchronous (interrupt) thread, then we can't sleep
     * (the tad ERRJMP flag is set at the start of async processing).
     */
    if (tad->tad_ctrl & TAD_ERRJMP) {
        buffer = kmem_cache_alloc(au_buf_cache, KM_NOSLEEP);
        if (buffer == NULL) {
            /* return to top of stack & report an error */
            ASSERT(tad->tad_errjmp);
            longjmp(tad->tad_errjmp);
        }
    } else {
        buffer = kmem_cache_alloc(au_buf_cache, KM_SLEEP);
    }
    /* Never gets here when buffer == NULL */
    bzero(buffer, sizeof (*buffer));
    return (buffer);
}

/*
 * Function: au_free_rec
 * args:
 *  au_buff_t *buf;     start of the record chain
 */
void
au_free_rec(au_buff_t *buf)
{
    au_buff_t *next;
    t_audit_data_t *tad = U2A(u);

    ASSERT(tad);

    /*
     * If asynchronous (interrupt) thread, schedule the release
     * (the tad ERRJMP flag is set at the start of async processing).
     */
    if (tad->tad_ctrl & TAD_ERRJMP) {
        /* Discard async events via softcall. */
        softcall(audit_async_discard_backend, buf);
    }

    while (buf != NULL) {
        next = buf->next_buf;
        kmem_cache_free(au_buf_cache, buf);
        buf = next;
    }
}

/*
 * Backend routine to discard an async event. Invoked from softcall.
 * (Note: the freeing of memory for the event can't be done safely in high
 * interrupt context due to the chance of sleeping on an adaptive mutex.
 * Hence the softcall.)
 */
void
audit_async_discard_backend(void *addr)
{
    au_toss_token(addr);
}

/*
 * Function: au_append_rec
 * args:
 *  au_buff_t *rec;     start of the record chain
 *  au_buff_t *buf;     buffer to append
 *  int        pack;    AU_PACK/1 - pack data, AU_LINK/0 - link buffer
 */
int
au_append_rec(au_buff_t *rec, au_buff_t *buf, int pack)
{
    if (!rec)
        return (-1);

    while (rec->next_buf)
        rec = rec->next_buf;
    if (((int)(rec->len + buf->len) <= AU_BUFSIZE) && pack) {
        bcopy(buf->buf, (char *)(rec->buf + rec->len),
            (uint_t)buf->len);
        rec->len += buf->len;
        rec->next_buf = buf->next_buf;
        kmem_cache_free(au_buf_cache, buf);
    } else {
        rec->next_buf = buf;
    }
    return (0);
}

/*
 * Function: au_append_buf
 * args:
 *  char *data;     data buffer to append
 *  int len;        size of data to append
 *  au_buff_t *buf;     buffer to append to
 */
int
au_append_buf(const char *data, int len, au_buff_t *buf)
{
    au_buff_t *new_buf;
    int new_len;

    while (buf->next_buf != NULL)
        buf = buf->next_buf;

    new_len = (uint_t)(buf->len + len) > AU_BUFSIZE ?
        AU_BUFSIZE - buf->len : len;
    bcopy(data, (buf->buf + buf->len), (uint_t)new_len);
    buf->len += (uchar_t)new_len;
    len -= new_len;

    while (len > 0) {
        data += new_len;
        if ((new_buf = au_get_buff()) == NULL) {
            return (-1);
        }
        buf->next_buf = new_buf;
        buf = new_buf;
        new_len = len > AU_BUFSIZE ? AU_BUFSIZE : len;
        bcopy(data, buf->buf, (uint_t)new_len);
        buf->len = (uchar_t)new_len;
        len -= new_len;
    }
    return (0);
}

void
au_mem_init()
{
    au_buf_cache = kmem_cache_create("audit_buffer",
        sizeof (au_buff_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
}