b8fbaf8c4b
avoid having to allocate space in the 'stackgap' - which is very LWP unfriendly. The additional code for non-emulation namei() is trivial, the reduction for the emulations is massive. The vnode for a processes emulation root is saved in the cwdi structure during process exec. If the emulation root the TRYEMULROOT flag are set, namei() will do an initial search for absolute pathnames in the emulation root, if that fails it will retry from the normal root. ".." at the emulation root will always go to the real root, even in the middle of paths and when expanding symlinks. Absolute symlinks found using absolute paths in the emulation root will be relative to the emulation root (so /usr/lib/xxx.so -> /lib/xxx.so links inside the emulation root don't need changing). If the root of the emulation would be returned (for an emulation lookup), then the real root is returned instead (matching the behaviour of emul_lookup, but being a cheap comparison here) so that programs that scan "../.." looking for the root dircetory don't loop forever. The target for symbolic links is no longer mangled (it used to get the CHECK_ALT_xxx() treatment, so could get /emul/xxx prepended). CHECK_ALT_xxx() are no more. Most of the change is deleting them, and adding TRYEMULROOT to the flags to NDINIT(). A lot of the emulation system call stubs could now be deleted.
477 lines
14 KiB
C
477 lines
14 KiB
C
/* $NetBSD: kern_acct.c,v 1.74 2007/04/22 08:30:00 dsl Exp $ */
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/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_acct.c 8.8 (Berkeley) 5/14/95
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*/
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/*-
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* Copyright (c) 1994 Christopher G. Demetriou
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_acct.c 8.8 (Berkeley) 5/14/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_acct.c,v 1.74 2007/04/22 08:30:00 dsl Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/syslog.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/malloc.h>
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#include <sys/namei.h>
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#include <sys/errno.h>
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#include <sys/acct.h>
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#include <sys/resourcevar.h>
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#include <sys/ioctl.h>
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#include <sys/tty.h>
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#include <sys/kauth.h>
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#include <sys/syscallargs.h>
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/*
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* The routines implemented in this file are described in:
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* Leffler, et al.: The Design and Implementation of the 4.3BSD
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* UNIX Operating System (Addison Welley, 1989)
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* on pages 62-63.
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*
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* Arguably, to simplify accounting operations, this mechanism should
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* be replaced by one in which an accounting log file (similar to /dev/klog)
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* is read by a user process, etc. However, that has its own problems.
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*/
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/*
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* Mutex to serialize system calls and kernel threads.
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*/
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kmutex_t acct_mutex;
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/*
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* The global accounting state and related data. Gain the mutex before
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* accessing these variables.
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*/
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static enum {
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ACCT_STOP,
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ACCT_ACTIVE,
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ACCT_SUSPENDED
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} acct_state; /* The current accounting state. */
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static struct vnode *acct_vp; /* Accounting vnode pointer. */
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static kauth_cred_t acct_cred; /* Credential of accounting file
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owner (i.e root). Used when
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accounting file i/o. */
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static struct proc *acct_dkwatcher; /* Free disk space checker. */
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/*
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* Values associated with enabling and disabling accounting
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*/
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int acctsuspend = 2; /* stop accounting when < 2% free space left */
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int acctresume = 4; /* resume when free space risen to > 4% */
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int acctchkfreq = 15; /* frequency (in seconds) to check space */
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/*
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* Encode_comp_t converts from ticks in seconds and microseconds
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* to ticks in 1/AHZ seconds. The encoding is described in
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* Leffler, et al., on page 63.
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*/
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#define MANTSIZE 13 /* 13 bit mantissa. */
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#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
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#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
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static comp_t
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encode_comp_t(u_long s, u_long us)
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{
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int exp, rnd;
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exp = 0;
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rnd = 0;
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s *= AHZ;
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s += us / (1000000 / AHZ); /* Maximize precision. */
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while (s > MAXFRACT) {
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rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
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s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
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exp++;
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}
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/* If we need to round up, do it (and handle overflow correctly). */
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if (rnd && (++s > MAXFRACT)) {
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s >>= EXPSIZE;
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exp++;
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}
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/* Clean it up and polish it off. */
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exp <<= MANTSIZE; /* Shift the exponent into place */
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exp += s; /* and add on the mantissa. */
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return (exp);
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}
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static int
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acct_chkfree(void)
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{
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int error;
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struct statvfs *sb;
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int64_t bavail;
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sb = malloc(sizeof(*sb), M_TEMP, M_WAITOK);
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error = VFS_STATVFS(acct_vp->v_mount, sb, NULL);
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if (error != 0)
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return (error);
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bavail = sb->f_bfree - sb->f_bresvd;
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switch (acct_state) {
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case ACCT_SUSPENDED:
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if (bavail > acctresume * sb->f_blocks / 100) {
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acct_state = ACCT_ACTIVE;
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log(LOG_NOTICE, "Accounting resumed\n");
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}
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break;
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case ACCT_ACTIVE:
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if (bavail <= acctsuspend * sb->f_blocks / 100) {
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acct_state = ACCT_SUSPENDED;
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log(LOG_NOTICE, "Accounting suspended\n");
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}
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break;
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case ACCT_STOP:
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break;
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}
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free(sb, M_TEMP);
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return (0);
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}
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static void
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acct_stop(void)
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{
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int error;
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if (acct_vp != NULLVP && acct_vp->v_type != VBAD) {
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error = vn_close(acct_vp, FWRITE, acct_cred, NULL);
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#ifdef DIAGNOSTIC
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if (error != 0)
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printf("acct_stop: failed to close, errno = %d\n",
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error);
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#endif
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acct_vp = NULLVP;
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}
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if (acct_cred != NULL) {
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kauth_cred_free(acct_cred);
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acct_cred = NULL;
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}
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acct_state = ACCT_STOP;
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}
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/*
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* Periodically check the file system to see if accounting
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* should be turned on or off. Beware the case where the vnode
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* has been vgone()'d out from underneath us, e.g. when the file
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* system containing the accounting file has been forcibly unmounted.
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*/
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static void
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acctwatch(void *arg)
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{
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int error;
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log(LOG_NOTICE, "Accounting started\n");
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mutex_enter(&acct_mutex);
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while (acct_state != ACCT_STOP) {
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if (acct_vp->v_type == VBAD) {
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log(LOG_NOTICE, "Accounting terminated\n");
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acct_stop();
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continue;
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}
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error = acct_chkfree();
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#ifdef DIAGNOSTIC
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if (error != 0)
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printf("acctwatch: failed to statvfs, error = %d\n",
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error);
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#endif
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error = kpause("actwat", false, acctchkfreq * hz, &acct_mutex);
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#ifdef DIAGNOSTIC
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if (error != 0 && error != EWOULDBLOCK)
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printf("acctwatch: sleep error %d\n", error);
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#endif
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}
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acct_dkwatcher = NULL;
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mutex_exit(&acct_mutex);
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kthread_exit(0);
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}
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void
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acct_init(void)
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{
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acct_state = ACCT_STOP;
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acct_vp = NULLVP;
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acct_cred = NULL;
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mutex_init(&acct_mutex, MUTEX_DEFAULT, IPL_NONE);
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}
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/*
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* Accounting system call. Written based on the specification and
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* previous implementation done by Mark Tinguely.
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*/
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int
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sys_acct(struct lwp *l, void *v, register_t *retval)
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{
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struct sys_acct_args /* {
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syscallarg(const char *) path;
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} */ *uap = v;
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struct nameidata nd;
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int error;
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/* Make sure that the caller is root. */
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if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_ACCOUNTING,
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0, NULL, NULL, NULL)))
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return (error);
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/*
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* If accounting is to be started to a file, open that file for
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* writing and make sure it's a 'normal'.
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*/
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if (SCARG(uap, path) != NULL) {
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struct vattr va;
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size_t pad;
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NDINIT(&nd, LOOKUP, NOFOLLOW | TRYEMULROOT, UIO_USERSPACE, SCARG(uap, path),
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l);
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if ((error = vn_open(&nd, FWRITE|O_APPEND, 0)) != 0)
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return (error);
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if (nd.ni_vp->v_type != VREG) {
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VOP_UNLOCK(nd.ni_vp, 0);
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error = EACCES;
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goto bad;
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}
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if ((error = VOP_GETATTR(nd.ni_vp, &va, l->l_cred, l)) != 0) {
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VOP_UNLOCK(nd.ni_vp, 0);
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goto bad;
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}
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if ((pad = (va.va_size % sizeof(struct acct))) != 0) {
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u_quad_t size = va.va_size - pad;
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#ifdef DIAGNOSTIC
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printf("Size of accounting file not a multiple of "
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"%lu - incomplete record truncated\n",
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(unsigned long)sizeof(struct acct));
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#endif
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VATTR_NULL(&va);
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va.va_size = size;
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error = VOP_SETATTR(nd.ni_vp, &va, l->l_cred, l);
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if (error != 0) {
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VOP_UNLOCK(nd.ni_vp, 0);
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goto bad;
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}
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}
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VOP_UNLOCK(nd.ni_vp, 0);
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}
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mutex_enter(&acct_mutex);
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/*
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* If accounting was previously enabled, kill the old space-watcher,
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* free credential for accounting file i/o,
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* ... (and, if no new file was specified, leave).
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*/
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acct_stop();
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if (SCARG(uap, path) == NULL)
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goto out;
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/*
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* Save the new accounting file vnode and credential,
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* and schedule the new free space watcher.
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*/
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acct_state = ACCT_ACTIVE;
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acct_vp = nd.ni_vp;
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acct_cred = l->l_cred;
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kauth_cred_hold(acct_cred);
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error = acct_chkfree(); /* Initial guess. */
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if (error != 0) {
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acct_stop();
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goto out;
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}
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if (acct_dkwatcher == NULL) {
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error = kthread_create1(acctwatch, NULL, &acct_dkwatcher,
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"acctwatch");
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if (error != 0)
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acct_stop();
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}
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out:
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mutex_exit(&acct_mutex);
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return (error);
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bad:
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vn_close(nd.ni_vp, FWRITE, l->l_cred, l);
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return error;
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}
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/*
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* Write out process accounting information, on process exit.
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* Data to be written out is specified in Leffler, et al.
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* and are enumerated below. (They're also noted in the system
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* "acct.h" header file.)
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*/
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int
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acct_process(struct lwp *l)
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{
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struct acct acct;
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struct timeval ut, st, tmp;
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struct rusage *r;
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int t, error = 0;
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struct plimit *oplim = NULL;
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struct proc *p = l->l_proc;
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mutex_enter(&acct_mutex);
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/* If accounting isn't enabled, don't bother */
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if (acct_state != ACCT_ACTIVE)
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goto out;
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/*
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* Raise the file limit so that accounting can't be stopped by
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* the user.
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*
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* XXX We should think about the CPU limit, too.
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*/
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mutex_enter(&p->p_mutex);
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if (p->p_limit->p_refcnt > 1) {
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oplim = p->p_limit;
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p->p_limit = limcopy(p);
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}
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p->p_rlimit[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
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mutex_exit(&p->p_mutex);
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/*
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* Get process accounting information.
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*/
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/* (1) The name of the command that ran */
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memcpy(acct.ac_comm, p->p_comm, sizeof(acct.ac_comm));
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/* (2) The amount of user and system time that was used */
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mutex_enter(&p->p_smutex);
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calcru(p, &ut, &st, NULL, NULL);
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mutex_exit(&p->p_smutex);
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acct.ac_utime = encode_comp_t(ut.tv_sec, ut.tv_usec);
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acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
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/* (3) The elapsed time the commmand ran (and its starting time) */
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acct.ac_btime = p->p_stats->p_start.tv_sec;
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getmicrotime(&tmp);
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timersub(&tmp, &p->p_stats->p_start, &tmp);
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acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
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/* (4) The average amount of memory used */
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r = &p->p_stats->p_ru;
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timeradd(&ut, &st, &tmp);
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t = tmp.tv_sec * hz + tmp.tv_usec / tick;
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if (t)
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acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
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else
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acct.ac_mem = 0;
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/* (5) The number of disk I/O operations done */
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acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
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/* (6) The UID and GID of the process */
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acct.ac_uid = kauth_cred_getuid(l->l_cred);
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acct.ac_gid = kauth_cred_getgid(l->l_cred);
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/* (7) The terminal from which the process was started */
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mutex_enter(&proclist_lock);
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if ((p->p_lflag & PL_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
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acct.ac_tty = p->p_pgrp->pg_session->s_ttyp->t_dev;
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else
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acct.ac_tty = NODEV;
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mutex_exit(&proclist_lock);
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/* (8) The boolean flags that tell how the process terminated, etc. */
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acct.ac_flag = p->p_acflag;
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/*
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* Now, just write the accounting information to the file.
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*/
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VOP_LEASE(acct_vp, l, l->l_cred, LEASE_WRITE);
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error = vn_rdwr(UIO_WRITE, acct_vp, (void *)&acct,
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sizeof(acct), (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT,
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acct_cred, NULL, NULL);
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if (error != 0)
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log(LOG_ERR, "Accounting: write failed %d\n", error);
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if (oplim) {
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mutex_enter(&p->p_mutex);
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limfree(p->p_limit);
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p->p_limit = oplim;
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mutex_exit(&p->p_mutex);
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}
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out:
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mutex_exit(&acct_mutex);
|
|
return (error);
|
|
}
|