kernel26-2.6.12-alx-r9/kernel/acct.c

/*
 *  linux/kernel/acct.c
 *
 *  BSD Process Accounting for Linux
 *
 *  Author: Marco van Wieringen <mvw@planets.elm.net>
 *
 *  Some code based on ideas and code from:
 *  Thomas K. Dyas <tdyas@eden.rutgers.edu>
 *
 *  This file implements BSD-style process accounting. Whenever any
 *  process exits, an accounting record of type "struct acct" is
 *  written to the file specified with the acct() system call. It is
 *  up to user-level programs to do useful things with the accounting
 *  log. The kernel just provides the raw accounting information.
 *
 * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
 *
 *  Plugged two leaks. 1) It didn't return acct_file into the free_filps if
 *  the file happened to be read-only. 2) If the accounting was suspended
 *  due to the lack of space it happily allowed to reopen it and completely
 *  lost the old acct_file. 3/10/98, Al Viro.
 *
 *  Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
 *  XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
 *
 *  Fixed a nasty interaction with with sys_umount(). If the accointing
 *  was suspeneded we failed to stop it on umount(). Messy.
 *  Another one: remount to readonly didn't stop accounting.
 *	Question: what should we do if we have CAP_SYS_ADMIN but not
 *  CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
 *  unless we are messing with the root. In that case we are getting a
 *  real mess with do_remount_sb(). 9/11/98, AV.
 *
 *  Fixed a bunch of races (and pair of leaks). Probably not the best way,
 *  but this one obviously doesn't introduce deadlocks. Later. BTW, found
 *  one race (and leak) in BSD implementation.
 *  OK, that's better. ANOTHER race and leak in BSD variant. There always
 *  is one more bug... 10/11/98, AV.
 *
 *	Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
 * ->mmap_sem to walk the vma list of current->mm. Nasty, since it leaks
 * a struct file opened for write. Fixed. 2/6/2000, AV.
 */

#include <linux/config.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/acct.h>
#include <linux/file.h>
#include <linux/tty.h>
#include <linux/security.h>
#include <linux/vfs.h>
#include <linux/jiffies.h>
#include <linux/times.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
#include <asm/div64.h>
#include <linux/blkdev.h> /* sector_div */

/*
 * These constants control the amount of freespace that suspend and
 * resume the process accounting system, and the time delay between
 * each check.
 * Turned into sysctl-controllable parameters. AV, 12/11/98
 */

int acct_parm[3] = {4, 2, 30};
#define RESUME		(acct_parm[0])	/* >foo% free space - resume */
#define SUSPEND		(acct_parm[1])	/* <foo% free space - suspend */
#define ACCT_TIMEOUT	(acct_parm[2])	/* foo second timeout between checks */

/*
 * External references and all of the globals.
 */
static void do_acct_process(long, struct file *);

/*
 * This structure is used so that all the data protected by lock
 * can be placed in the same cache line as the lock.  This primes
 * the cache line to have the data after getting the lock.
 */
struct acct_glbs {
	spinlock_t		lock;
	volatile int		active;
	volatile int		needcheck;
	struct file		*file;
	struct timer_list	timer;
};

static struct acct_glbs acct_globals __cacheline_aligned = {SPIN_LOCK_UNLOCKED};

/*
 * Called whenever the timer says to check the free space.
 */
static void acct_timeout(unsigned long unused)
{
	acct_globals.needcheck = 1;
}

/*
 * Check the amount of free space and suspend/resume accordingly.
 */
static int check_free_space(struct file *file)
{
	struct kstatfs sbuf;
	int res;
	int act;
	sector_t resume;
	sector_t suspend;

	spin_lock(&acct_globals.lock);
	res = acct_globals.active;
	if (!file || !acct_globals.needcheck)
		goto out;
	spin_unlock(&acct_globals.lock);

	/* May block */
	if (vfs_statfs(file->f_dentry->d_inode->i_sb, &sbuf))
		return res;
	suspend = sbuf.f_blocks * SUSPEND;
	resume = sbuf.f_blocks * RESUME;

	sector_div(suspend, 100);
	sector_div(resume, 100);

	if (sbuf.f_bavail <= suspend)
		act = -1;
	else if (sbuf.f_bavail >= resume)
		act = 1;
	else
		act = 0;

	/*
	 * If some joker switched acct_globals.file under us we'ld better be
	 * silent and _not_ touch anything.
	 */
	spin_lock(&acct_globals.lock);
	if (file != acct_globals.file) {
		if (act)
			res = act>0;
		goto out;
	}

	if (acct_globals.active) {
		if (act < 0) {
			acct_globals.active = 0;
			printk(KERN_INFO "Process accounting paused\n");
		}
	} else {
		if (act > 0) {
			acct_globals.active = 1;
			printk(KERN_INFO "Process accounting resumed\n");
		}
	}

	del_timer(&acct_globals.timer);
	acct_globals.needcheck = 0;
	acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ;
	add_timer(&acct_globals.timer);
	res = acct_globals.active;
out:
	spin_unlock(&acct_globals.lock);
	return res;
}

/*
 * Close the old accouting file (if currently open) and then replace
 * it with file (if non-NULL).
 *
 * NOTE: acct_globals.lock MUST be held on entry and exit.
 */
static void acct_file_reopen(struct file *file)
{
	struct file *old_acct = NULL;

	if (acct_globals.file) {
		old_acct = acct_globals.file;
		del_timer(&acct_globals.timer);
		acct_globals.active = 0;
		acct_globals.needcheck = 0;
		acct_globals.file = NULL;
	}
	if (file) {
		acct_globals.file = file;
		acct_globals.needcheck = 0;
		acct_globals.active = 1;
		/* It's been deleted if it was used before so this is safe */
		init_timer(&acct_globals.timer);
		acct_globals.timer.function = acct_timeout;
		acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ;
		add_timer(&acct_globals.timer);
	}
	if (old_acct) {
		spin_unlock(&acct_globals.lock);
		do_acct_process(0, old_acct);
		filp_close(old_acct, NULL);
		spin_lock(&acct_globals.lock);
	}
}

/*
 *  sys_acct() is the only system call needed to implement process
 *  accounting. It takes the name of the file where accounting records
 *  should be written. If the filename is NULL, accounting will be
 *  shutdown.
 */
asmlinkage long sys_acct(const char __user *name)
{
	struct file *file = NULL;
	char *tmp;
	int error;

	if (!capable(CAP_SYS_PACCT))
		return -EPERM;

	if (name) {
		tmp = getname(name);
		if (IS_ERR(tmp)) {
			return (PTR_ERR(tmp));
		}
		/* Difference from BSD - they don't do O_APPEND */
		file = filp_open(tmp, O_WRONLY|O_APPEND, 0);
		putname(tmp);
		if (IS_ERR(file)) {
			return (PTR_ERR(file));
		}
		if (!S_ISREG(file->f_dentry->d_inode->i_mode)) {
			filp_close(file, NULL);
			return (-EACCES);
		}

		if (!file->f_op->write) {
			filp_close(file, NULL);
			return (-EIO);
		}
	}

	error = security_acct(file);
	if (error) {
		if (file)
			filp_close(file, NULL);
		return error;
	}

	spin_lock(&acct_globals.lock);
	acct_file_reopen(file);
	spin_unlock(&acct_globals.lock);

	return (0);
}

/*
 * If the accouting is turned on for a file in the filesystem pointed
 * to by sb, turn accouting off.
 */
void acct_auto_close(struct super_block *sb)
{
	spin_lock(&acct_globals.lock);
	if (acct_globals.file &&
	    acct_globals.file->f_dentry->d_inode->i_sb == sb) {
		acct_file_reopen((struct file *)NULL);
	}
	spin_unlock(&acct_globals.lock);
}

/*
 *  encode an unsigned long into a comp_t
 *
 *  This routine has been adopted from the encode_comp_t() function in
 *  the kern_acct.c file of the FreeBSD operating system. The encoding
 *  is a 13-bit fraction with a 3-bit (base 8) exponent.
 */

#define	MANTSIZE	13			/* 13 bit mantissa. */
#define	EXPSIZE		3			/* Base 8 (3 bit) exponent. */
#define	MAXFRACT	((1 << MANTSIZE) - 1)	/* Maximum fractional value. */

static comp_t encode_comp_t(unsigned long value)
{
	int exp, rnd;

	exp = rnd = 0;
	while (value > MAXFRACT) {
		rnd = value & (1 << (EXPSIZE - 1));	/* Round up? */
		value >>= EXPSIZE;	/* Base 8 exponent == 3 bit shift. */
		exp++;
	}

	/*
         * If we need to round up, do it (and handle overflow correctly).
         */
	if (rnd && (++value > MAXFRACT)) {
		value >>= EXPSIZE;
		exp++;
	}

	/*
         * Clean it up and polish it off.
         */
	exp <<= MANTSIZE;		/* Shift the exponent into place */
	exp += value;			/* and add on the mantissa. */
	return exp;
}

#if ACCT_VERSION==1 || ACCT_VERSION==2
/*
 * encode an u64 into a comp2_t (24 bits)
 *
 * Format: 5 bit base 2 exponent, 20 bits mantissa.
 * The leading bit of the mantissa is not stored, but implied for
 * non-zero exponents.
 * Largest encodable value is 50 bits.
 */

#define MANTSIZE2       20                      /* 20 bit mantissa. */
#define EXPSIZE2        5                       /* 5 bit base 2 exponent. */
#define MAXFRACT2       ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
#define MAXEXP2         ((1 <<EXPSIZE2) - 1)    /* Maximum exponent. */

static comp2_t encode_comp2_t(u64 value)
{
        int exp, rnd;

        exp = (value > (MAXFRACT2>>1));
        rnd = 0;
        while (value > MAXFRACT2) {
                rnd = value & 1;
                value >>= 1;
                exp++;
        }

        /*
         * If we need to round up, do it (and handle overflow correctly).
         */
        if (rnd && (++value > MAXFRACT2)) {
                value >>= 1;
                exp++;
        }

        if (exp > MAXEXP2) {
                /* Overflow. Return largest representable number instead. */
                return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
        } else {
                return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
        }
}
#endif

#if ACCT_VERSION==3
/*
 * encode an u64 into a 32 bit IEEE float
 */
static u32 encode_float(u64 value)
{
	unsigned exp = 190;
	unsigned u;

	if (value==0) return 0;
	while ((s64)value > 0){
		value <<= 1;
		exp--;
	}
	u = (u32)(value >> 40) & 0x7fffffu;
	return u | (exp << 23);
}
#endif

/*
 *  Write an accounting entry for an exiting process
 *
 *  The acct_process() call is the workhorse of the process
 *  accounting system. The struct acct is built here and then written
 *  into the accounting file. This function should only be called from
 *  do_exit().
 */

/*
 *  do_acct_process does all actual work. Caller holds the reference to file.
 */
static void do_acct_process(long exitcode, struct file *file)
{
	acct_t ac;
	mm_segment_t fs;
	unsigned long vsize;
	unsigned long flim;
	u64 elapsed;
	u64 run_time;
	struct timespec uptime;

	/*
	 * First check to see if there is enough free_space to continue
	 * the process accounting system.
	 */
	if (!check_free_space(file))
		return;

	/*
	 * Fill the accounting struct with the needed info as recorded
	 * by the different kernel functions.
	 */
	memset((caddr_t)&ac, 0, sizeof(acct_t));

	ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER;
	strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));

	/* calculate run_time in nsec*/
	do_posix_clock_monotonic_gettime(&uptime);
	run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec;
	run_time -= (u64)current->start_time.tv_sec*NSEC_PER_SEC
					+ current->start_time.tv_nsec;
	/* convert nsec -> AHZ */
	elapsed = nsec_to_AHZ(run_time);
#if ACCT_VERSION==3
	ac.ac_etime = encode_float(elapsed);
#else
	ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
	                       (unsigned long) elapsed : (unsigned long) -1l);
#endif
#if ACCT_VERSION==1 || ACCT_VERSION==2
	{
		/* new enlarged etime field */
		comp2_t etime = encode_comp2_t(elapsed);
		ac.ac_etime_hi = etime >> 16;
		ac.ac_etime_lo = (u16) etime;
	}
#endif
	do_div(elapsed, AHZ);
	ac.ac_btime = xtime.tv_sec - elapsed;
	ac.ac_utime = encode_comp_t(jiffies_to_AHZ(
					    current->signal->utime +
					    current->group_leader->utime));
	ac.ac_stime = encode_comp_t(jiffies_to_AHZ(
					    current->signal->stime +
					    current->group_leader->stime));
	/* we really need to bite the bullet and change layout */
	ac.ac_uid = current->uid;
	ac.ac_gid = current->gid;
#if ACCT_VERSION==2
	ac.ac_ahz = AHZ;
#endif
#if ACCT_VERSION==1 || ACCT_VERSION==2
	/* backward-compatible 16 bit fields */
	ac.ac_uid16 = current->uid;
	ac.ac_gid16 = current->gid;
#endif
#if ACCT_VERSION==3
	ac.ac_pid = current->tgid;
	ac.ac_ppid = current->parent->tgid;
#endif

	read_lock(&tasklist_lock);	/* pin current->signal */
	ac.ac_tty = current->signal->tty ?
		old_encode_dev(tty_devnum(current->signal->tty)) : 0;
	read_unlock(&tasklist_lock);

	ac.ac_flag = 0;
	if (current->flags & PF_FORKNOEXEC)
		ac.ac_flag |= AFORK;
	if (current->flags & PF_SUPERPRIV)
		ac.ac_flag |= ASU;
	if (current->flags & PF_DUMPCORE)
		ac.ac_flag |= ACORE;
	if (current->flags & PF_SIGNALED)
		ac.ac_flag |= AXSIG;

	vsize = 0;
	if (current->mm) {
		struct vm_area_struct *vma;
		down_read(&current->mm->mmap_sem);
		vma = current->mm->mmap;
		while (vma) {
			vsize += vma->vm_end - vma->vm_start;
			vma = vma->vm_next;
		}
		up_read(&current->mm->mmap_sem);
	}
	vsize = vsize / 1024;
	ac.ac_mem = encode_comp_t(vsize);
	ac.ac_io = encode_comp_t(0 /* current->io_usage */);	/* %% */
	ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
	ac.ac_minflt = encode_comp_t(current->signal->min_flt +
				     current->group_leader->min_flt);
	ac.ac_majflt = encode_comp_t(current->signal->maj_flt +
				     current->group_leader->maj_flt);
	ac.ac_swaps = encode_comp_t(0);
	ac.ac_exitcode = exitcode;

	/*
         * Kernel segment override to datasegment and write it
         * to the accounting file.
         */
	fs = get_fs();
	set_fs(KERNEL_DS);
	/*
 	 * Accounting records are not subject to resource limits.
 	 */
	flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
	file->f_op->write(file, (char *)&ac,
			       sizeof(acct_t), &file->f_pos);
	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
	set_fs(fs);
}

/*
 * acct_process - now just a wrapper around do_acct_process
 */
void acct_process(long exitcode)
{
	struct file *file = NULL;

	/*
	 * accelerate the common fastpath:
	 */
	if (!acct_globals.file)
		return;

	spin_lock(&acct_globals.lock);
	file = acct_globals.file;
	if (unlikely(!file)) {
		spin_unlock(&acct_globals.lock);
		return;
	}
	get_file(file);
	spin_unlock(&acct_globals.lock);

	do_acct_process(exitcode, file);
	fput(file);
}


/*
 * acct_update_integrals
 *    -  update mm integral fields in task_struct
 */
void acct_update_integrals(struct task_struct *tsk)
{
	if (likely(tsk->mm)) {
		long delta = tsk->stime - tsk->acct_stimexpd;

		if (delta == 0)
			return;
		tsk->acct_stimexpd = tsk->stime;
		tsk->acct_rss_mem1 += delta * get_mm_counter(tsk->mm, rss);
		tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;
	}
}

/*
 * acct_clear_integrals
 *    - clear the mm integral fields in task_struct
 */
void acct_clear_integrals(struct task_struct *tsk)
{
	if (tsk) {
		tsk->acct_stimexpd = 0;
		tsk->acct_rss_mem1 = 0;
		tsk->acct_vm_mem1 = 0;
	}
}
1	niro	628	/*
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(&current->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(&current->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			}