Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/kernel/acct.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 14796 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
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 | |
46 | #include <linux/config.h> |
47 | #include <linux/mm.h> |
48 | #include <linux/slab.h> |
49 | #include <linux/acct.h> |
50 | #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> |
57 | #include <asm/uaccess.h> |
58 | #include <asm/div64.h> |
59 | #include <linux/blkdev.h> /* sector_div */ |
60 | |
61 | /* |
62 | * These constants control the amount of freespace that suspend and |
63 | * resume the process accounting system, and the time delay between |
64 | * each check. |
65 | * Turned into sysctl-controllable parameters. AV, 12/11/98 |
66 | */ |
67 | |
68 | int acct_parm[3] = {4, 2, 30}; |
69 | #define RESUME (acct_parm[0]) /* >foo% free space - resume */ |
70 | #define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */ |
71 | #define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */ |
72 | |
73 | /* |
74 | * External references and all of the globals. |
75 | */ |
76 | static void do_acct_process(long, struct file *); |
77 | |
78 | /* |
79 | * This structure is used so that all the data protected by lock |
80 | * can be placed in the same cache line as the lock. This primes |
81 | * the cache line to have the data after getting the lock. |
82 | */ |
83 | struct acct_glbs { |
84 | spinlock_t lock; |
85 | volatile int active; |
86 | volatile int needcheck; |
87 | struct file *file; |
88 | struct timer_list timer; |
89 | }; |
90 | |
91 | static struct acct_glbs acct_globals __cacheline_aligned = {SPIN_LOCK_UNLOCKED}; |
92 | |
93 | /* |
94 | * Called whenever the timer says to check the free space. |
95 | */ |
96 | static void acct_timeout(unsigned long unused) |
97 | { |
98 | acct_globals.needcheck = 1; |
99 | } |
100 | |
101 | /* |
102 | * Check the amount of free space and suspend/resume accordingly. |
103 | */ |
104 | static int check_free_space(struct file *file) |
105 | { |
106 | struct kstatfs sbuf; |
107 | int res; |
108 | int act; |
109 | sector_t resume; |
110 | sector_t suspend; |
111 | |
112 | spin_lock(&acct_globals.lock); |
113 | res = acct_globals.active; |
114 | if (!file || !acct_globals.needcheck) |
115 | goto out; |
116 | spin_unlock(&acct_globals.lock); |
117 | |
118 | /* May block */ |
119 | if (vfs_statfs(file->f_dentry->d_inode->i_sb, &sbuf)) |
120 | return res; |
121 | suspend = sbuf.f_blocks * SUSPEND; |
122 | resume = sbuf.f_blocks * RESUME; |
123 | |
124 | sector_div(suspend, 100); |
125 | sector_div(resume, 100); |
126 | |
127 | if (sbuf.f_bavail <= suspend) |
128 | act = -1; |
129 | else if (sbuf.f_bavail >= resume) |
130 | act = 1; |
131 | else |
132 | act = 0; |
133 | |
134 | /* |
135 | * If some joker switched acct_globals.file under us we'ld better be |
136 | * silent and _not_ touch anything. |
137 | */ |
138 | spin_lock(&acct_globals.lock); |
139 | if (file != acct_globals.file) { |
140 | if (act) |
141 | res = act>0; |
142 | goto out; |
143 | } |
144 | |
145 | if (acct_globals.active) { |
146 | if (act < 0) { |
147 | acct_globals.active = 0; |
148 | printk(KERN_INFO "Process accounting paused\n"); |
149 | } |
150 | } else { |
151 | if (act > 0) { |
152 | acct_globals.active = 1; |
153 | printk(KERN_INFO "Process accounting resumed\n"); |
154 | } |
155 | } |
156 | |
157 | del_timer(&acct_globals.timer); |
158 | acct_globals.needcheck = 0; |
159 | acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ; |
160 | add_timer(&acct_globals.timer); |
161 | res = acct_globals.active; |
162 | out: |
163 | spin_unlock(&acct_globals.lock); |
164 | return res; |
165 | } |
166 | |
167 | /* |
168 | * Close the old accouting file (if currently open) and then replace |
169 | * it with file (if non-NULL). |
170 | * |
171 | * NOTE: acct_globals.lock MUST be held on entry and exit. |
172 | */ |
173 | static void acct_file_reopen(struct file *file) |
174 | { |
175 | struct file *old_acct = NULL; |
176 | |
177 | if (acct_globals.file) { |
178 | old_acct = acct_globals.file; |
179 | del_timer(&acct_globals.timer); |
180 | acct_globals.active = 0; |
181 | acct_globals.needcheck = 0; |
182 | acct_globals.file = NULL; |
183 | } |
184 | if (file) { |
185 | acct_globals.file = file; |
186 | acct_globals.needcheck = 0; |
187 | acct_globals.active = 1; |
188 | /* It's been deleted if it was used before so this is safe */ |
189 | init_timer(&acct_globals.timer); |
190 | acct_globals.timer.function = acct_timeout; |
191 | acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ; |
192 | add_timer(&acct_globals.timer); |
193 | } |
194 | if (old_acct) { |
195 | spin_unlock(&acct_globals.lock); |
196 | do_acct_process(0, old_acct); |
197 | filp_close(old_acct, NULL); |
198 | spin_lock(&acct_globals.lock); |
199 | } |
200 | } |
201 | |
202 | /* |
203 | * sys_acct() is the only system call needed to implement process |
204 | * accounting. It takes the name of the file where accounting records |
205 | * should be written. If the filename is NULL, accounting will be |
206 | * shutdown. |
207 | */ |
208 | asmlinkage long sys_acct(const char __user *name) |
209 | { |
210 | struct file *file = NULL; |
211 | char *tmp; |
212 | int error; |
213 | |
214 | if (!capable(CAP_SYS_PACCT)) |
215 | return -EPERM; |
216 | |
217 | if (name) { |
218 | tmp = getname(name); |
219 | if (IS_ERR(tmp)) { |
220 | return (PTR_ERR(tmp)); |
221 | } |
222 | /* Difference from BSD - they don't do O_APPEND */ |
223 | file = filp_open(tmp, O_WRONLY|O_APPEND, 0); |
224 | putname(tmp); |
225 | if (IS_ERR(file)) { |
226 | return (PTR_ERR(file)); |
227 | } |
228 | if (!S_ISREG(file->f_dentry->d_inode->i_mode)) { |
229 | filp_close(file, NULL); |
230 | return (-EACCES); |
231 | } |
232 | |
233 | if (!file->f_op->write) { |
234 | filp_close(file, NULL); |
235 | return (-EIO); |
236 | } |
237 | } |
238 | |
239 | error = security_acct(file); |
240 | if (error) { |
241 | if (file) |
242 | filp_close(file, NULL); |
243 | return error; |
244 | } |
245 | |
246 | spin_lock(&acct_globals.lock); |
247 | acct_file_reopen(file); |
248 | spin_unlock(&acct_globals.lock); |
249 | |
250 | return (0); |
251 | } |
252 | |
253 | /* |
254 | * If the accouting is turned on for a file in the filesystem pointed |
255 | * to by sb, turn accouting off. |
256 | */ |
257 | void acct_auto_close(struct super_block *sb) |
258 | { |
259 | spin_lock(&acct_globals.lock); |
260 | if (acct_globals.file && |
261 | acct_globals.file->f_dentry->d_inode->i_sb == sb) { |
262 | acct_file_reopen((struct file *)NULL); |
263 | } |
264 | spin_unlock(&acct_globals.lock); |
265 | } |
266 | |
267 | /* |
268 | * encode an unsigned long into a comp_t |
269 | * |
270 | * This routine has been adopted from the encode_comp_t() function in |
271 | * the kern_acct.c file of the FreeBSD operating system. The encoding |
272 | * is a 13-bit fraction with a 3-bit (base 8) exponent. |
273 | */ |
274 | |
275 | #define MANTSIZE 13 /* 13 bit mantissa. */ |
276 | #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ |
277 | #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ |
278 | |
279 | static comp_t encode_comp_t(unsigned long value) |
280 | { |
281 | int exp, rnd; |
282 | |
283 | exp = rnd = 0; |
284 | while (value > MAXFRACT) { |
285 | rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */ |
286 | value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ |
287 | exp++; |
288 | } |
289 | |
290 | /* |
291 | * If we need to round up, do it (and handle overflow correctly). |
292 | */ |
293 | if (rnd && (++value > MAXFRACT)) { |
294 | value >>= EXPSIZE; |
295 | exp++; |
296 | } |
297 | |
298 | /* |
299 | * Clean it up and polish it off. |
300 | */ |
301 | exp <<= MANTSIZE; /* Shift the exponent into place */ |
302 | exp += value; /* and add on the mantissa. */ |
303 | return exp; |
304 | } |
305 | |
306 | #if ACCT_VERSION==1 || ACCT_VERSION==2 |
307 | /* |
308 | * encode an u64 into a comp2_t (24 bits) |
309 | * |
310 | * Format: 5 bit base 2 exponent, 20 bits mantissa. |
311 | * The leading bit of the mantissa is not stored, but implied for |
312 | * non-zero exponents. |
313 | * Largest encodable value is 50 bits. |
314 | */ |
315 | |
316 | #define MANTSIZE2 20 /* 20 bit mantissa. */ |
317 | #define EXPSIZE2 5 /* 5 bit base 2 exponent. */ |
318 | #define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */ |
319 | #define MAXEXP2 ((1 <<EXPSIZE2) - 1) /* Maximum exponent. */ |
320 | |
321 | static comp2_t encode_comp2_t(u64 value) |
322 | { |
323 | int exp, rnd; |
324 | |
325 | exp = (value > (MAXFRACT2>>1)); |
326 | rnd = 0; |
327 | while (value > MAXFRACT2) { |
328 | rnd = value & 1; |
329 | value >>= 1; |
330 | exp++; |
331 | } |
332 | |
333 | /* |
334 | * If we need to round up, do it (and handle overflow correctly). |
335 | */ |
336 | if (rnd && (++value > MAXFRACT2)) { |
337 | value >>= 1; |
338 | exp++; |
339 | } |
340 | |
341 | if (exp > MAXEXP2) { |
342 | /* Overflow. Return largest representable number instead. */ |
343 | return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1; |
344 | } else { |
345 | return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1)); |
346 | } |
347 | } |
348 | #endif |
349 | |
350 | #if ACCT_VERSION==3 |
351 | /* |
352 | * encode an u64 into a 32 bit IEEE float |
353 | */ |
354 | static u32 encode_float(u64 value) |
355 | { |
356 | unsigned exp = 190; |
357 | unsigned u; |
358 | |
359 | if (value==0) return 0; |
360 | while ((s64)value > 0){ |
361 | value <<= 1; |
362 | exp--; |
363 | } |
364 | u = (u32)(value >> 40) & 0x7fffffu; |
365 | return u | (exp << 23); |
366 | } |
367 | #endif |
368 | |
369 | /* |
370 | * Write an accounting entry for an exiting process |
371 | * |
372 | * The acct_process() call is the workhorse of the process |
373 | * accounting system. The struct acct is built here and then written |
374 | * into the accounting file. This function should only be called from |
375 | * do_exit(). |
376 | */ |
377 | |
378 | /* |
379 | * do_acct_process does all actual work. Caller holds the reference to file. |
380 | */ |
381 | static void do_acct_process(long exitcode, struct file *file) |
382 | { |
383 | acct_t ac; |
384 | mm_segment_t fs; |
385 | unsigned long vsize; |
386 | unsigned long flim; |
387 | u64 elapsed; |
388 | u64 run_time; |
389 | struct timespec uptime; |
390 | |
391 | /* |
392 | * First check to see if there is enough free_space to continue |
393 | * the process accounting system. |
394 | */ |
395 | if (!check_free_space(file)) |
396 | return; |
397 | |
398 | /* |
399 | * Fill the accounting struct with the needed info as recorded |
400 | * by the different kernel functions. |
401 | */ |
402 | memset((caddr_t)&ac, 0, sizeof(acct_t)); |
403 | |
404 | ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER; |
405 | strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm)); |
406 | |
407 | /* calculate run_time in nsec*/ |
408 | do_posix_clock_monotonic_gettime(&uptime); |
409 | run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec; |
410 | run_time -= (u64)current->start_time.tv_sec*NSEC_PER_SEC |
411 | + current->start_time.tv_nsec; |
412 | /* convert nsec -> AHZ */ |
413 | elapsed = nsec_to_AHZ(run_time); |
414 | #if ACCT_VERSION==3 |
415 | ac.ac_etime = encode_float(elapsed); |
416 | #else |
417 | ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? |
418 | (unsigned long) elapsed : (unsigned long) -1l); |
419 | #endif |
420 | #if ACCT_VERSION==1 || ACCT_VERSION==2 |
421 | { |
422 | /* new enlarged etime field */ |
423 | comp2_t etime = encode_comp2_t(elapsed); |
424 | ac.ac_etime_hi = etime >> 16; |
425 | ac.ac_etime_lo = (u16) etime; |
426 | } |
427 | #endif |
428 | do_div(elapsed, AHZ); |
429 | ac.ac_btime = xtime.tv_sec - elapsed; |
430 | ac.ac_utime = encode_comp_t(jiffies_to_AHZ( |
431 | current->signal->utime + |
432 | current->group_leader->utime)); |
433 | ac.ac_stime = encode_comp_t(jiffies_to_AHZ( |
434 | current->signal->stime + |
435 | current->group_leader->stime)); |
436 | /* we really need to bite the bullet and change layout */ |
437 | ac.ac_uid = current->uid; |
438 | ac.ac_gid = current->gid; |
439 | #if ACCT_VERSION==2 |
440 | ac.ac_ahz = AHZ; |
441 | #endif |
442 | #if ACCT_VERSION==1 || ACCT_VERSION==2 |
443 | /* backward-compatible 16 bit fields */ |
444 | ac.ac_uid16 = current->uid; |
445 | ac.ac_gid16 = current->gid; |
446 | #endif |
447 | #if ACCT_VERSION==3 |
448 | ac.ac_pid = current->tgid; |
449 | ac.ac_ppid = current->parent->tgid; |
450 | #endif |
451 | |
452 | read_lock(&tasklist_lock); /* pin current->signal */ |
453 | ac.ac_tty = current->signal->tty ? |
454 | old_encode_dev(tty_devnum(current->signal->tty)) : 0; |
455 | read_unlock(&tasklist_lock); |
456 | |
457 | ac.ac_flag = 0; |
458 | if (current->flags & PF_FORKNOEXEC) |
459 | ac.ac_flag |= AFORK; |
460 | if (current->flags & PF_SUPERPRIV) |
461 | ac.ac_flag |= ASU; |
462 | if (current->flags & PF_DUMPCORE) |
463 | ac.ac_flag |= ACORE; |
464 | if (current->flags & PF_SIGNALED) |
465 | ac.ac_flag |= AXSIG; |
466 | |
467 | vsize = 0; |
468 | if (current->mm) { |
469 | struct vm_area_struct *vma; |
470 | down_read(¤t->mm->mmap_sem); |
471 | vma = current->mm->mmap; |
472 | while (vma) { |
473 | vsize += vma->vm_end - vma->vm_start; |
474 | vma = vma->vm_next; |
475 | } |
476 | up_read(¤t->mm->mmap_sem); |
477 | } |
478 | vsize = vsize / 1024; |
479 | ac.ac_mem = encode_comp_t(vsize); |
480 | ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */ |
481 | ac.ac_rw = encode_comp_t(ac.ac_io / 1024); |
482 | ac.ac_minflt = encode_comp_t(current->signal->min_flt + |
483 | current->group_leader->min_flt); |
484 | ac.ac_majflt = encode_comp_t(current->signal->maj_flt + |
485 | current->group_leader->maj_flt); |
486 | ac.ac_swaps = encode_comp_t(0); |
487 | ac.ac_exitcode = exitcode; |
488 | |
489 | /* |
490 | * Kernel segment override to datasegment and write it |
491 | * to the accounting file. |
492 | */ |
493 | fs = get_fs(); |
494 | set_fs(KERNEL_DS); |
495 | /* |
496 | * Accounting records are not subject to resource limits. |
497 | */ |
498 | flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
499 | current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; |
500 | file->f_op->write(file, (char *)&ac, |
501 | sizeof(acct_t), &file->f_pos); |
502 | current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; |
503 | set_fs(fs); |
504 | } |
505 | |
506 | /* |
507 | * acct_process - now just a wrapper around do_acct_process |
508 | */ |
509 | void acct_process(long exitcode) |
510 | { |
511 | struct file *file = NULL; |
512 | |
513 | /* |
514 | * accelerate the common fastpath: |
515 | */ |
516 | if (!acct_globals.file) |
517 | return; |
518 | |
519 | spin_lock(&acct_globals.lock); |
520 | file = acct_globals.file; |
521 | if (unlikely(!file)) { |
522 | spin_unlock(&acct_globals.lock); |
523 | return; |
524 | } |
525 | get_file(file); |
526 | spin_unlock(&acct_globals.lock); |
527 | |
528 | do_acct_process(exitcode, file); |
529 | fput(file); |
530 | } |
531 | |
532 | |
533 | /* |
534 | * acct_update_integrals |
535 | * - update mm integral fields in task_struct |
536 | */ |
537 | void acct_update_integrals(struct task_struct *tsk) |
538 | { |
539 | if (likely(tsk->mm)) { |
540 | long delta = tsk->stime - tsk->acct_stimexpd; |
541 | |
542 | if (delta == 0) |
543 | return; |
544 | tsk->acct_stimexpd = tsk->stime; |
545 | tsk->acct_rss_mem1 += delta * get_mm_counter(tsk->mm, rss); |
546 | tsk->acct_vm_mem1 += delta * tsk->mm->total_vm; |
547 | } |
548 | } |
549 | |
550 | /* |
551 | * acct_clear_integrals |
552 | * - clear the mm integral fields in task_struct |
553 | */ |
554 | void acct_clear_integrals(struct task_struct *tsk) |
555 | { |
556 | if (tsk) { |
557 | tsk->acct_stimexpd = 0; |
558 | tsk->acct_rss_mem1 = 0; |
559 | tsk->acct_vm_mem1 = 0; |
560 | } |
561 | } |