Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 561 insertions, 0 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
new file mode 100644
index 000000000000..4168f631868e
--- /dev/null
+++ b/kernel/acct.c
@@ -0,0 +1,561 @@
+/*
+ *  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;
+	}
+}