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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/acct.c
3 *
4 * BSD Process Accounting for Linux
5 *
6 * Author: Marco van Wieringen <mvw@planets.elm.net>
7 *
8 * Some code based on ideas and code from:
9 * Thomas K. Dyas <tdyas@eden.rutgers.edu>
10 *
11 * This file implements BSD-style process accounting. Whenever any
12 * process exits, an accounting record of type "struct acct" is
13 * written to the file specified with the acct() system call. It is
14 * up to user-level programs to do useful things with the accounting
15 * log. The kernel just provides the raw accounting information.
16 *
17 * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
18 *
19 * Plugged two leaks. 1) It didn't return acct_file into the free_filps if
20 * the file happened to be read-only. 2) If the accounting was suspended
21 * due to the lack of space it happily allowed to reopen it and completely
22 * lost the old acct_file. 3/10/98, Al Viro.
23 *
24 * Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
25 * XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
26 *
27 * Fixed a nasty interaction with with sys_umount(). If the accointing
28 * was suspeneded we failed to stop it on umount(). Messy.
29 * Another one: remount to readonly didn't stop accounting.
30 * Question: what should we do if we have CAP_SYS_ADMIN but not
31 * CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
32 * unless we are messing with the root. In that case we are getting a
33 * real mess with do_remount_sb(). 9/11/98, AV.
34 *
35 * Fixed a bunch of races (and pair of leaks). Probably not the best way,
36 * but this one obviously doesn't introduce deadlocks. Later. BTW, found
37 * one race (and leak) in BSD implementation.
38 * OK, that's better. ANOTHER race and leak in BSD variant. There always
39 * is one more bug... 10/11/98, AV.
40 *
41 * Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
42 * ->mmap_sem to walk the vma list of current->mm. Nasty, since it leaks
43 * a struct file opened for write. Fixed. 2/6/2000, AV.
44 */
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/mm.h>
47#include <linux/slab.h>
48#include <linux/acct.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080049#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#include <linux/file.h>
51#include <linux/tty.h>
52#include <linux/security.h>
53#include <linux/vfs.h>
54#include <linux/jiffies.h>
55#include <linux/times.h>
56#include <linux/syscalls.h>
Al Viro7b7b1ac2005-11-07 17:13:39 -050057#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058#include <asm/uaccess.h>
59#include <asm/div64.h>
60#include <linux/blkdev.h> /* sector_div */
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -070061#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/*
64 * These constants control the amount of freespace that suspend and
65 * resume the process accounting system, and the time delay between
66 * each check.
67 * Turned into sysctl-controllable parameters. AV, 12/11/98
68 */
69
70int acct_parm[3] = {4, 2, 30};
71#define RESUME (acct_parm[0]) /* >foo% free space - resume */
72#define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */
73#define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */
74
75/*
76 * External references and all of the globals.
77 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -070078static void do_acct_process(struct bsd_acct_struct *acct,
79 struct pid_namespace *ns, struct file *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81/*
82 * This structure is used so that all the data protected by lock
83 * can be placed in the same cache line as the lock. This primes
84 * the cache line to have the data after getting the lock.
85 */
Pavel Emelyanov081e4c82008-07-25 01:48:42 -070086struct bsd_acct_struct {
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 volatile int active;
88 volatile int needcheck;
89 struct file *file;
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -070090 struct pid_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 struct timer_list timer;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -070092 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093};
94
Pavel Emelyanova75d9792008-07-25 01:48:45 -070095static DEFINE_SPINLOCK(acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -070096static LIST_HEAD(acct_list);
Pavel Emelyanova75d9792008-07-25 01:48:45 -070097
Linus Torvalds1da177e2005-04-16 15:20:36 -070098/*
99 * Called whenever the timer says to check the free space.
100 */
Pavel Emelyanove59a04a2008-07-25 01:48:44 -0700101static void acct_timeout(unsigned long x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102{
Pavel Emelyanove59a04a2008-07-25 01:48:44 -0700103 struct bsd_acct_struct *acct = (struct bsd_acct_struct *)x;
104 acct->needcheck = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
106
107/*
108 * Check the amount of free space and suspend/resume accordingly.
109 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700110static int check_free_space(struct bsd_acct_struct *acct, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111{
112 struct kstatfs sbuf;
113 int res;
114 int act;
115 sector_t resume;
116 sector_t suspend;
117
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700118 spin_lock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700119 res = acct->active;
120 if (!file || !acct->needcheck)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 goto out;
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700122 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
124 /* May block */
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200125 if (vfs_statfs(&file->f_path, &sbuf))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 return res;
127 suspend = sbuf.f_blocks * SUSPEND;
128 resume = sbuf.f_blocks * RESUME;
129
130 sector_div(suspend, 100);
131 sector_div(resume, 100);
132
133 if (sbuf.f_bavail <= suspend)
134 act = -1;
135 else if (sbuf.f_bavail >= resume)
136 act = 1;
137 else
138 act = 0;
139
140 /*
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700141 * If some joker switched acct->file under us we'ld better be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 * silent and _not_ touch anything.
143 */
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700144 spin_lock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700145 if (file != acct->file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 if (act)
147 res = act>0;
148 goto out;
149 }
150
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700151 if (acct->active) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 if (act < 0) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700153 acct->active = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 printk(KERN_INFO "Process accounting paused\n");
155 }
156 } else {
157 if (act > 0) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700158 acct->active = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 printk(KERN_INFO "Process accounting resumed\n");
160 }
161 }
162
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700163 del_timer(&acct->timer);
164 acct->needcheck = 0;
165 acct->timer.expires = jiffies + ACCT_TIMEOUT*HZ;
166 add_timer(&acct->timer);
167 res = acct->active;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168out:
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700169 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 return res;
171}
172
173/*
Randy Dunlap417ef532005-09-10 00:26:39 -0700174 * Close the old accounting file (if currently open) and then replace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 * it with file (if non-NULL).
176 *
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700177 * NOTE: acct_lock MUST be held on entry and exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700179static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
180 struct pid_namespace *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181{
182 struct file *old_acct = NULL;
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700183 struct pid_namespace *old_ns = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700185 if (acct->file) {
186 old_acct = acct->file;
187 old_ns = acct->ns;
188 del_timer(&acct->timer);
189 acct->active = 0;
190 acct->needcheck = 0;
191 acct->file = NULL;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700192 acct->ns = NULL;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700193 list_del(&acct->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 }
195 if (file) {
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700196 acct->file = file;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700197 acct->ns = ns;
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700198 acct->needcheck = 0;
199 acct->active = 1;
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700200 list_add(&acct->list, &acct_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 /* It's been deleted if it was used before so this is safe */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700202 setup_timer(&acct->timer, acct_timeout, (unsigned long)acct);
203 acct->timer.expires = jiffies + ACCT_TIMEOUT*HZ;
204 add_timer(&acct->timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 }
206 if (old_acct) {
Josef "Jeff" Sipekf3a43f32006-12-08 02:36:43 -0800207 mnt_unpin(old_acct->f_path.mnt);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700208 spin_unlock(&acct_lock);
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700209 do_acct_process(acct, old_ns, old_acct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 filp_close(old_acct, NULL);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700211 spin_lock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 }
213}
214
Al Viro7b7b1ac2005-11-07 17:13:39 -0500215static int acct_on(char *name)
216{
217 struct file *file;
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700218 struct vfsmount *mnt;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700219 struct pid_namespace *ns;
220 struct bsd_acct_struct *acct = NULL;
Al Viro7b7b1ac2005-11-07 17:13:39 -0500221
222 /* Difference from BSD - they don't do O_APPEND */
223 file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
224 if (IS_ERR(file))
225 return PTR_ERR(file);
226
Josef "Jeff" Sipekf3a43f32006-12-08 02:36:43 -0800227 if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) {
Al Viro7b7b1ac2005-11-07 17:13:39 -0500228 filp_close(file, NULL);
229 return -EACCES;
230 }
231
232 if (!file->f_op->write) {
233 filp_close(file, NULL);
234 return -EIO;
235 }
236
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700237 ns = task_active_pid_ns(current);
238 if (ns->bacct == NULL) {
239 acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
240 if (acct == NULL) {
241 filp_close(file, NULL);
242 return -ENOMEM;
243 }
244 }
245
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700246 spin_lock(&acct_lock);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700247 if (ns->bacct == NULL) {
248 ns->bacct = acct;
249 acct = NULL;
250 }
251
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700252 mnt = file->f_path.mnt;
253 mnt_pin(mnt);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700254 acct_file_reopen(ns->bacct, file, ns);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700255 spin_unlock(&acct_lock);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500256
Renaud Lottiauxdf279ca2009-06-30 11:41:34 -0700257 mntput(mnt); /* it's pinned, now give up active reference */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700258 kfree(acct);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500259
260 return 0;
261}
262
Randy Dunlap417ef532005-09-10 00:26:39 -0700263/**
264 * sys_acct - enable/disable process accounting
265 * @name: file name for accounting records or NULL to shutdown accounting
266 *
267 * Returns 0 for success or negative errno values for failure.
268 *
269 * sys_acct() is the only system call needed to implement process
270 * accounting. It takes the name of the file where accounting records
271 * should be written. If the filename is NULL, accounting will be
272 * shutdown.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 */
Heiko Carstensb290ebe2009-01-14 14:14:06 +0100274SYSCALL_DEFINE1(acct, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275{
Eric Paris05b90492010-04-07 15:15:25 -0400276 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
278 if (!capable(CAP_SYS_PACCT))
279 return -EPERM;
280
281 if (name) {
Al Viro7b7b1ac2005-11-07 17:13:39 -0500282 char *tmp = getname(name);
283 if (IS_ERR(tmp))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 return (PTR_ERR(tmp));
Al Viro7b7b1ac2005-11-07 17:13:39 -0500285 error = acct_on(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 putname(tmp);
Al Viro7b7b1ac2005-11-07 17:13:39 -0500287 } else {
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700288 struct bsd_acct_struct *acct;
289
290 acct = task_active_pid_ns(current)->bacct;
291 if (acct == NULL)
292 return 0;
293
Eric Paris05b90492010-04-07 15:15:25 -0400294 spin_lock(&acct_lock);
295 acct_file_reopen(acct, NULL, NULL);
296 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 }
Eric Paris05b90492010-04-07 15:15:25 -0400298
Al Viro7b7b1ac2005-11-07 17:13:39 -0500299 return error;
300}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
Al Viro7b7b1ac2005-11-07 17:13:39 -0500302/**
303 * acct_auto_close - turn off a filesystem's accounting if it is on
304 * @m: vfsmount being shut down
305 *
306 * If the accounting is turned on for a file in the subtree pointed to
307 * to by m, turn accounting off. Done when m is about to die.
308 */
309void acct_auto_close_mnt(struct vfsmount *m)
310{
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700311 struct bsd_acct_struct *acct;
312
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700313 spin_lock(&acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700314restart:
315 list_for_each_entry(acct, &acct_list, list)
316 if (acct->file && acct->file->f_path.mnt == m) {
317 acct_file_reopen(acct, NULL, NULL);
318 goto restart;
319 }
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700320 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321}
322
Randy Dunlap417ef532005-09-10 00:26:39 -0700323/**
324 * acct_auto_close - turn off a filesystem's accounting if it is on
325 * @sb: super block for the filesystem
326 *
327 * If the accounting is turned on for a file in the filesystem pointed
328 * to by sb, turn accounting off.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 */
330void acct_auto_close(struct super_block *sb)
331{
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700332 struct bsd_acct_struct *acct;
333
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700334 spin_lock(&acct_lock);
Pavel Emelyanovb5a71742008-07-25 01:48:47 -0700335restart:
336 list_for_each_entry(acct, &acct_list, list)
337 if (acct->file && acct->file->f_path.mnt->mnt_sb == sb) {
338 acct_file_reopen(acct, NULL, NULL);
339 goto restart;
340 }
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700341 spin_unlock(&acct_lock);
342}
343
344void acct_exit_ns(struct pid_namespace *ns)
345{
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700346 struct bsd_acct_struct *acct = ns->bacct;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700347
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700348 if (acct == NULL)
349 return;
350
351 del_timer_sync(&acct->timer);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700352 spin_lock(&acct_lock);
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700353 if (acct->file != NULL)
354 acct_file_reopen(acct, NULL, NULL);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700355 spin_unlock(&acct_lock);
Vitaliy Gusev11cad322010-05-11 14:06:56 -0700356
357 kfree(acct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358}
359
360/*
361 * encode an unsigned long into a comp_t
362 *
363 * This routine has been adopted from the encode_comp_t() function in
364 * the kern_acct.c file of the FreeBSD operating system. The encoding
365 * is a 13-bit fraction with a 3-bit (base 8) exponent.
366 */
367
368#define MANTSIZE 13 /* 13 bit mantissa. */
369#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
370#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
371
372static comp_t encode_comp_t(unsigned long value)
373{
374 int exp, rnd;
375
376 exp = rnd = 0;
377 while (value > MAXFRACT) {
378 rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */
379 value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
380 exp++;
381 }
382
383 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700384 * If we need to round up, do it (and handle overflow correctly).
385 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 if (rnd && (++value > MAXFRACT)) {
387 value >>= EXPSIZE;
388 exp++;
389 }
390
391 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700392 * Clean it up and polish it off.
393 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 exp <<= MANTSIZE; /* Shift the exponent into place */
395 exp += value; /* and add on the mantissa. */
396 return exp;
397}
398
399#if ACCT_VERSION==1 || ACCT_VERSION==2
400/*
401 * encode an u64 into a comp2_t (24 bits)
402 *
403 * Format: 5 bit base 2 exponent, 20 bits mantissa.
404 * The leading bit of the mantissa is not stored, but implied for
405 * non-zero exponents.
406 * Largest encodable value is 50 bits.
407 */
408
409#define MANTSIZE2 20 /* 20 bit mantissa. */
410#define EXPSIZE2 5 /* 5 bit base 2 exponent. */
411#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
412#define MAXEXP2 ((1 <<EXPSIZE2) - 1) /* Maximum exponent. */
413
414static comp2_t encode_comp2_t(u64 value)
415{
Daniel Walker6ae965c2007-10-18 03:06:04 -0700416 int exp, rnd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
Daniel Walker6ae965c2007-10-18 03:06:04 -0700418 exp = (value > (MAXFRACT2>>1));
419 rnd = 0;
420 while (value > MAXFRACT2) {
421 rnd = value & 1;
422 value >>= 1;
423 exp++;
424 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
Daniel Walker6ae965c2007-10-18 03:06:04 -0700426 /*
427 * If we need to round up, do it (and handle overflow correctly).
428 */
429 if (rnd && (++value > MAXFRACT2)) {
430 value >>= 1;
431 exp++;
432 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433
Daniel Walker6ae965c2007-10-18 03:06:04 -0700434 if (exp > MAXEXP2) {
435 /* Overflow. Return largest representable number instead. */
436 return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
437 } else {
438 return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
439 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440}
441#endif
442
443#if ACCT_VERSION==3
444/*
445 * encode an u64 into a 32 bit IEEE float
446 */
447static u32 encode_float(u64 value)
448{
449 unsigned exp = 190;
450 unsigned u;
451
452 if (value==0) return 0;
453 while ((s64)value > 0){
454 value <<= 1;
455 exp--;
456 }
457 u = (u32)(value >> 40) & 0x7fffffu;
458 return u | (exp << 23);
459}
460#endif
461
462/*
463 * Write an accounting entry for an exiting process
464 *
465 * The acct_process() call is the workhorse of the process
466 * accounting system. The struct acct is built here and then written
467 * into the accounting file. This function should only be called from
Ingo Molnarbcbe4a02007-11-26 21:21:49 +0100468 * do_exit() or when switching to a different output file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 */
470
471/*
472 * do_acct_process does all actual work. Caller holds the reference to file.
473 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700474static void do_acct_process(struct bsd_acct_struct *acct,
475 struct pid_namespace *ns, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476{
KaiGai Kohei0e464812006-06-25 05:49:24 -0700477 struct pacct_struct *pacct = &current->signal->pacct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 acct_t ac;
479 mm_segment_t fs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 unsigned long flim;
481 u64 elapsed;
482 u64 run_time;
483 struct timespec uptime;
Peter Zijlstra24ec8392006-12-08 02:36:04 -0800484 struct tty_struct *tty;
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700485 const struct cred *orig_cred;
486
487 /* Perform file operations on behalf of whoever enabled accounting */
488 orig_cred = override_creds(file->f_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
490 /*
491 * First check to see if there is enough free_space to continue
492 * the process accounting system.
493 */
Pavel Emelyanov6248b1b2008-07-25 01:48:46 -0700494 if (!check_free_space(acct, file))
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700495 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496
497 /*
498 * Fill the accounting struct with the needed info as recorded
499 * by the different kernel functions.
500 */
501 memset((caddr_t)&ac, 0, sizeof(acct_t));
502
503 ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER;
504 strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));
505
506 /* calculate run_time in nsec*/
507 do_posix_clock_monotonic_gettime(&uptime);
508 run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec;
KaiGai Koheibb231fe2006-03-31 02:30:45 -0800509 run_time -= (u64)current->group_leader->start_time.tv_sec * NSEC_PER_SEC
510 + current->group_leader->start_time.tv_nsec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 /* convert nsec -> AHZ */
512 elapsed = nsec_to_AHZ(run_time);
513#if ACCT_VERSION==3
514 ac.ac_etime = encode_float(elapsed);
515#else
516 ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
517 (unsigned long) elapsed : (unsigned long) -1l);
518#endif
519#if ACCT_VERSION==1 || ACCT_VERSION==2
520 {
521 /* new enlarged etime field */
522 comp2_t etime = encode_comp2_t(elapsed);
523 ac.ac_etime_hi = etime >> 16;
524 ac.ac_etime_lo = (u16) etime;
525 }
526#endif
527 do_div(elapsed, AHZ);
john stultz2c6b47d2007-07-24 17:47:43 -0700528 ac.ac_btime = get_seconds() - elapsed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 /* we really need to bite the bullet and change layout */
Alexey Dobriyan4b731d52009-12-14 17:57:34 -0800530 ac.ac_uid = orig_cred->uid;
531 ac.ac_gid = orig_cred->gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532#if ACCT_VERSION==2
533 ac.ac_ahz = AHZ;
534#endif
535#if ACCT_VERSION==1 || ACCT_VERSION==2
536 /* backward-compatible 16 bit fields */
David Howells76aac0e2008-11-14 10:39:12 +1100537 ac.ac_uid16 = ac.ac_uid;
538 ac.ac_gid16 = ac.ac_gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539#endif
540#if ACCT_VERSION==3
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700541 ac.ac_pid = task_tgid_nr_ns(current, ns);
Pavel Emelyanova846a192008-03-24 12:29:52 -0700542 rcu_read_lock();
Pavel Emelyanov5f7b7032008-03-24 12:29:53 -0700543 ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns);
Pavel Emelyanova846a192008-03-24 12:29:52 -0700544 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545#endif
546
OGAWA Hirofumia4afee02006-07-14 00:24:18 -0700547 spin_lock_irq(&current->sighand->siglock);
Alan Coxdbda4c02008-10-13 10:40:53 +0100548 tty = current->signal->tty; /* Safe as we hold the siglock */
Oleg Nesterov7bcfa952006-12-08 02:36:07 -0800549 ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700550 ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
551 ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700552 ac.ac_flag = pacct->ac_flag;
KaiGai Kohei0e464812006-06-25 05:49:24 -0700553 ac.ac_mem = encode_comp_t(pacct->ac_mem);
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700554 ac.ac_minflt = encode_comp_t(pacct->ac_minflt);
555 ac.ac_majflt = encode_comp_t(pacct->ac_majflt);
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700556 ac.ac_exitcode = pacct->ac_exitcode;
OGAWA Hirofumia4afee02006-07-14 00:24:18 -0700557 spin_unlock_irq(&current->sighand->siglock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */
559 ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 ac.ac_swaps = encode_comp_t(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700563 * Kernel segment override to datasegment and write it
564 * to the accounting file.
565 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 fs = get_fs();
567 set_fs(KERNEL_DS);
568 /*
Daniel Walker6ae965c2007-10-18 03:06:04 -0700569 * Accounting records are not subject to resource limits.
570 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
572 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
573 file->f_op->write(file, (char *)&ac,
574 sizeof(acct_t), &file->f_pos);
575 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
576 set_fs(fs);
Michal Schmidtd8e180d2009-08-20 14:39:52 -0700577out:
578 revert_creds(orig_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579}
580
Randy Dunlap417ef532005-09-10 00:26:39 -0700581/**
KaiGai Kohei0e464812006-06-25 05:49:24 -0700582 * acct_collect - collect accounting information into pacct_struct
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700583 * @exitcode: task exit code
584 * @group_dead: not 0, if this thread is the last one in the process.
KaiGai Kohei0e464812006-06-25 05:49:24 -0700585 */
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700586void acct_collect(long exitcode, int group_dead)
KaiGai Kohei0e464812006-06-25 05:49:24 -0700587{
588 struct pacct_struct *pacct = &current->signal->pacct;
589 unsigned long vsize = 0;
590
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700591 if (group_dead && current->mm) {
KaiGai Kohei0e464812006-06-25 05:49:24 -0700592 struct vm_area_struct *vma;
593 down_read(&current->mm->mmap_sem);
594 vma = current->mm->mmap;
595 while (vma) {
596 vsize += vma->vm_end - vma->vm_start;
597 vma = vma->vm_next;
598 }
599 up_read(&current->mm->mmap_sem);
600 }
601
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700602 spin_lock_irq(&current->sighand->siglock);
KaiGai Koheif6ec29a2006-06-25 05:49:25 -0700603 if (group_dead)
604 pacct->ac_mem = vsize / 1024;
605 if (thread_group_leader(current)) {
606 pacct->ac_exitcode = exitcode;
607 if (current->flags & PF_FORKNOEXEC)
608 pacct->ac_flag |= AFORK;
609 }
610 if (current->flags & PF_SUPERPRIV)
611 pacct->ac_flag |= ASU;
612 if (current->flags & PF_DUMPCORE)
613 pacct->ac_flag |= ACORE;
614 if (current->flags & PF_SIGNALED)
615 pacct->ac_flag |= AXSIG;
KaiGai Kohei77787bf2006-06-25 05:49:26 -0700616 pacct->ac_utime = cputime_add(pacct->ac_utime, current->utime);
617 pacct->ac_stime = cputime_add(pacct->ac_stime, current->stime);
618 pacct->ac_minflt += current->min_flt;
619 pacct->ac_majflt += current->maj_flt;
620 spin_unlock_irq(&current->sighand->siglock);
KaiGai Kohei0e464812006-06-25 05:49:24 -0700621}
622
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700623static void acct_process_in_ns(struct pid_namespace *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624{
625 struct file *file = NULL;
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700626 struct bsd_acct_struct *acct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700628 acct = ns->bacct;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 /*
630 * accelerate the common fastpath:
631 */
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700632 if (!acct || !acct->file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return;
634
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700635 spin_lock(&acct_lock);
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700636 file = acct->file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 if (unlikely(!file)) {
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700638 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 return;
640 }
641 get_file(file);
Pavel Emelyanova75d9792008-07-25 01:48:45 -0700642 spin_unlock(&acct_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
Pavel Emelyanov0b6b0302008-07-25 01:48:47 -0700644 do_acct_process(acct, ns, file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 fput(file);
646}
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700647
648/**
Pavel Emelyanov0c18d7a2008-07-25 01:48:49 -0700649 * acct_process - now just a wrapper around acct_process_in_ns,
650 * which in turn is a wrapper around do_acct_process.
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700651 *
652 * handles process accounting for an exiting task
653 */
654void acct_process(void)
655{
656 struct pid_namespace *ns;
657
Pavel Emelyanov0c18d7a2008-07-25 01:48:49 -0700658 /*
659 * This loop is safe lockless, since current is still
660 * alive and holds its namespace, which in turn holds
661 * its parent.
662 */
Pavel Emelyanov7d1e1352008-07-25 01:48:48 -0700663 for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
664 acct_process_in_ns(ns);
665}