kernel - Major signal path adjustments to fix races, tsleep race fixes, +more
[dragonfly.git] / sys / kern / kern_acct.c
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1/*-
2 * Copyright (c) 1994 Christopher G. Demetriou
3 * Copyright (c) 1982, 1986, 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 * (c) UNIX System Laboratories, Inc.
6 * All or some portions of this file are derived from material licensed
7 * to the University of California by American Telephone and Telegraph
8 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9 * the permission of UNIX System Laboratories, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)kern_acct.c 8.1 (Berkeley) 6/14/93
40 * $FreeBSD: src/sys/kern/kern_acct.c,v 1.23.2.1 2002/07/24 18:33:55 johan Exp $
8f1f6170 41 * $DragonFly: src/sys/kern/kern_acct.c,v 1.28 2008/05/08 01:26:00 dillon Exp $
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42 */
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/sysproto.h>
47#include <sys/proc.h>
895c1f85 48#include <sys/priv.h>
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49#include <sys/mount.h>
50#include <sys/vnode.h>
51#include <sys/fcntl.h>
52#include <sys/syslog.h>
53#include <sys/kernel.h>
54#include <sys/sysent.h>
55#include <sys/sysctl.h>
fad57d0e 56#include <sys/nlookup.h>
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57#include <sys/acct.h>
58#include <sys/resourcevar.h>
59#include <sys/tty.h>
60
61#include <vm/vm_zone.h>
62
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63#include <sys/mplock2.h>
64
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65/*
66 * The routines implemented in this file are described in:
67 * Leffler, et al.: The Design and Implementation of the 4.3BSD
68 * UNIX Operating System (Addison Welley, 1989)
69 * on pages 62-63.
70 *
71 * Arguably, to simplify accounting operations, this mechanism should
72 * be replaced by one in which an accounting log file (similar to /dev/klog)
73 * is read by a user process, etc. However, that has its own problems.
74 */
75
76/*
77 * Internal accounting functions.
78 * The former's operation is described in Leffler, et al., and the latter
79 * was provided by UCB with the 4.4BSD-Lite release
80 */
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81static comp_t encode_comp_t (u_long, u_long);
82static void acctwatch (void *);
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83
84/*
85 * Accounting callout handle used for periodic scheduling of
86 * acctwatch.
87 */
5972dfb9 88static struct callout acctwatch_handle;
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89
90/*
91 * Accounting vnode pointer, and saved vnode pointer.
92 */
93static struct vnode *acctp;
94static struct vnode *savacctp;
95
96/*
97 * Values associated with enabling and disabling accounting
98 */
99static int acctsuspend = 2; /* stop accounting when < 2% free space left */
100SYSCTL_INT(_kern, OID_AUTO, acct_suspend, CTLFLAG_RW,
06723abb 101 &acctsuspend, 0, "Percentage of free disk space below which accounting will be suspended");
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102
103static int acctresume = 4; /* resume when free space risen to > 4% */
104SYSCTL_INT(_kern, OID_AUTO, acct_resume, CTLFLAG_RW,
06723abb 105 &acctresume, 0, "Minimum percentage of free disk space needed to resume accounting");
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106
107static int acctchkfreq = 15; /* frequency (in seconds) to check space */
108SYSCTL_INT(_kern, OID_AUTO, acct_chkfreq, CTLFLAG_RW,
06723abb 109 &acctchkfreq, 0, "Frequency (in seconds) of free disk space checking");
984263bc 110
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111static void
112acct_init(void *arg __unused)
113{
114 callout_init(&acctwatch_handle);
115}
116SYSINIT(acct, SI_SUB_DRIVERS, SI_ORDER_ANY, acct_init, NULL);
117
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118/*
119 * Accounting system call. Written based on the specification and
120 * previous implementation done by Mark Tinguely.
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121 *
122 * acct(char *path)
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123 *
124 * MPALMOSTSAFE
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125 */
126int
753fd850 127sys_acct(struct acct_args *uap)
984263bc 128{
dadab5e9 129 struct thread *td = curthread;
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130 struct nlookupdata nd;
131 struct vnode *vp;
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132 int error;
133
d550b5e6 134 error = priv_check(td, PRIV_ACCT);
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135 if (error)
136 return (error);
137
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138 get_mplock();
139
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140 /*
141 * If accounting is to be started to a file, open that file for
142 * appending and make sure it's a 'normal'.
143 */
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144 if (uap->path != NULL) {
145 error = nlookup_init(&nd, uap->path, UIO_USERSPACE,
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146 NLC_LOCKVP);
147 if (error == 0)
148 error = vn_open(&nd, NULL, FWRITE | O_APPEND, 0);
149 if (error == 0 && nd.nl_open_vp->v_type != VREG)
150 error = EACCES;
151 if (error) {
152 nlookup_done(&nd);
3919ced0 153 goto done;
984263bc 154 }
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155 vp = nd.nl_open_vp;
156 nd.nl_open_vp = NULL;
157 nlookup_done(&nd);
158
a11aaa81 159 vn_unlock(vp);
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160 } else {
161 vp = NULL;
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162 }
163
164 /*
165 * If accounting was previously enabled, kill the old space-watcher,
fad57d0e 166 * close the file.
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167 */
168 if (acctp != NULLVP || savacctp != NULLVP) {
5972dfb9 169 callout_stop(&acctwatch_handle);
984263bc 170 error = vn_close((acctp != NULLVP ? acctp : savacctp),
87de5057 171 FWRITE | O_APPEND);
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172 acctp = savacctp = NULLVP;
173 }
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174
175 /*
176 * If no new file opened then leave. We never did an nlookup so
177 * don't try cleaning it up.
178 */
ab2eb4eb 179 if (uap->path == NULL)
3919ced0 180 goto done;
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181
182 /*
183 * Save the new accounting file vnode, and schedule the new
184 * free space watcher.
185 */
fad57d0e 186 acctp = vp;
984263bc 187 acctwatch(NULL);
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188done:
189 rel_mplock();
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190 return (error);
191}
192
193/*
194 * Write out process accounting information, on process exit.
195 * Data to be written out is specified in Leffler, et al.
196 * and are enumerated below. (They're also noted in the system
197 * "acct.h" header file.)
198 */
199
200int
dadab5e9 201acct_process(struct proc *p)
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202{
203 struct acct acct;
204 struct rusage *r;
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205 struct rusage ru;
206 struct timeval tmp;
c0b8a06d 207 struct rlimit rlim;
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208 int t;
209 struct vnode *vp;
210
211 /* If accounting isn't enabled, don't bother */
212 vp = acctp;
213 if (vp == NULLVP)
214 return (0);
215
216 /*
217 * Get process accounting information.
218 */
219
220 /* (1) The name of the command that ran */
221 bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
222
223 /* (2) The amount of user and system time that was used */
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224 calcru_proc(p, &ru);
225 acct.ac_utime = encode_comp_t(ru.ru_utime.tv_sec, ru.ru_utime.tv_usec);
226 acct.ac_stime = encode_comp_t(ru.ru_stime.tv_sec, ru.ru_stime.tv_usec);
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227
228 /* (3) The elapsed time the commmand ran (and its starting time) */
d9fa5f67 229 acct.ac_btime = p->p_start.tv_sec;
984263bc 230 microtime(&tmp);
d9fa5f67 231 timevalsub(&tmp, &p->p_start);
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232 acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
233
234 /* (4) The average amount of memory used */
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235 r = &p->p_ru;
236 tmp = ru.ru_utime;;
237 timevaladd(&tmp, &ru.ru_stime);
a591f597 238 t = tmp.tv_sec * hz + tmp.tv_usec / ustick;
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239 if (t)
240 acct.ac_mem = (r->ru_ixrss + r->ru_idrss + r->ru_isrss) / t;
241 else
242 acct.ac_mem = 0;
243
244 /* (5) The number of disk I/O operations done */
245 acct.ac_io = encode_comp_t(r->ru_inblock + r->ru_oublock, 0);
246
247 /* (6) The UID and GID of the process */
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248 acct.ac_uid = p->p_ucred->cr_ruid;
249 acct.ac_gid = p->p_ucred->cr_rgid;
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250
251 /* (7) The terminal from which the process was started */
4643740a 252 if ((p->p_flags & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
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253 acct.ac_tty = dev2udev(p->p_pgrp->pg_session->s_ttyp->t_dev);
254 else
255 acct.ac_tty = NOUDEV;
256
257 /* (8) The boolean flags that tell how the process terminated, etc. */
258 acct.ac_flag = p->p_acflag;
259
260 /*
261 * Eliminate any file size rlimit.
262 */
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263 rlim.rlim_cur = RLIM_INFINITY;
264 rlim.rlim_max = RLIM_INFINITY;
8f1f6170 265 plimit_modify(p, RLIMIT_FSIZE, &rlim);
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266
267 /*
268 * Write the accounting information to the file.
269 */
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270 return (vn_rdwr(UIO_WRITE, vp, (caddr_t)&acct, sizeof (acct),
271 (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, p->p_ucred,
60233e58 272 NULL));
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273}
274
275/*
276 * Encode_comp_t converts from ticks in seconds and microseconds
277 * to ticks in 1/AHZ seconds. The encoding is described in
278 * Leffler, et al., on page 63.
279 */
280
281#define MANTSIZE 13 /* 13 bit mantissa. */
282#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
283#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
284
285static comp_t
77153250 286encode_comp_t(u_long s, u_long us)
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287{
288 int exp, rnd;
289
290 exp = 0;
291 rnd = 0;
292 s *= AHZ;
293 s += us / (1000000 / AHZ); /* Maximize precision. */
294
295 while (s > MAXFRACT) {
296 rnd = s & (1 << (EXPSIZE - 1)); /* Round up? */
297 s >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
298 exp++;
299 }
300
301 /* If we need to round up, do it (and handle overflow correctly). */
302 if (rnd && (++s > MAXFRACT)) {
303 s >>= EXPSIZE;
304 exp++;
305 }
306
307 /* Clean it up and polish it off. */
308 exp <<= MANTSIZE; /* Shift the exponent into place */
309 exp += s; /* and add on the mantissa. */
310 return (exp);
311}
312
313/*
314 * Periodically check the file system to see if accounting
315 * should be turned on or off. Beware the case where the vnode
316 * has been vgone()'d out from underneath us, e.g. when the file
317 * system containing the accounting file has been forcibly unmounted.
318 */
319/* ARGSUSED */
320static void
77153250 321acctwatch(void *a)
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322{
323 struct statfs sb;
324
325 if (savacctp != NULLVP) {
326 if (savacctp->v_type == VBAD) {
87de5057 327 (void) vn_close(savacctp, FWRITE | O_APPEND);
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328 savacctp = NULLVP;
329 return;
330 }
acde96db 331 (void)VFS_STATFS(savacctp->v_mount, &sb, proc0.p_ucred);
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332 if (sb.f_bavail > acctresume * sb.f_blocks / 100) {
333 acctp = savacctp;
334 savacctp = NULLVP;
335 log(LOG_NOTICE, "Accounting resumed\n");
336 }
337 } else {
338 if (acctp == NULLVP)
339 return;
340 if (acctp->v_type == VBAD) {
87de5057 341 (void) vn_close(acctp, FWRITE | O_APPEND);
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342 acctp = NULLVP;
343 return;
344 }
acde96db 345 (void)VFS_STATFS(acctp->v_mount, &sb, proc0.p_ucred);
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346 if (sb.f_bavail <= acctsuspend * sb.f_blocks / 100) {
347 savacctp = acctp;
348 acctp = NULLVP;
349 log(LOG_NOTICE, "Accounting suspended\n");
350 }
351 }
5972dfb9 352 callout_reset(&acctwatch_handle, acctchkfreq * hz, acctwatch, NULL);
984263bc 353}