X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Facct.c;h=a6605ca921b6a6a9538ac645dadee177ef34f9b9;hb=84c95c9acf088c99d8793d78036b67faa5d0b851;hp=72d4760c8da833930e804b3c1f6d924125bf1924;hpb=6248b1b342005a428b1247b4e89249da1528d88d;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/acct.c b/kernel/acct.c
index 72d4760..a6605ca 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -89,11 +89,11 @@ struct bsd_acct_struct {
 	struct file		*file;
 	struct pid_namespace	*ns;
 	struct timer_list	timer;
+	struct list_head	list;
 };
 
 static DEFINE_SPINLOCK(acct_lock);
-
-static struct bsd_acct_struct acct_globals __cacheline_aligned;
+static LIST_HEAD(acct_list);
 
 /*
  * Called whenever the timer says to check the free space.
@@ -176,7 +176,8 @@ out:
  *
  * NOTE: acct_lock MUST be held on entry and exit.
  */
-static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file)
+static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
+		struct pid_namespace *ns)
 {
 	struct file *old_acct = NULL;
 	struct pid_namespace *old_ns = NULL;
@@ -188,12 +189,15 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file)
 		acct->active = 0;
 		acct->needcheck = 0;
 		acct->file = NULL;
+		acct->ns = NULL;
+		list_del(&acct->list);
 	}
 	if (file) {
 		acct->file = file;
-		acct->ns = get_pid_ns(task_active_pid_ns(current));
+		acct->ns = ns;
 		acct->needcheck = 0;
 		acct->active = 1;
+		list_add(&acct->list, &acct_list);
 		/* It's been deleted if it was used before so this is safe */
 		setup_timer(&acct->timer, acct_timeout, (unsigned long)acct);
 		acct->timer.expires = jiffies + ACCT_TIMEOUT*HZ;
@@ -204,7 +208,6 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file)
 		spin_unlock(&acct_lock);
 		do_acct_process(acct, old_ns, old_acct);
 		filp_close(old_acct, NULL);
-		put_pid_ns(old_ns);
 		spin_lock(&acct_lock);
 	}
 }
@@ -212,7 +215,10 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file)
 static int acct_on(char *name)
 {
 	struct file *file;
+	struct vfsmount *mnt;
 	int error;
+	struct pid_namespace *ns;
+	struct bsd_acct_struct *acct = NULL;
 
 	/* Difference from BSD - they don't do O_APPEND */
 	file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
@@ -229,18 +235,35 @@ static int acct_on(char *name)
 		return -EIO;
 	}
 
+	ns = task_active_pid_ns(current);
+	if (ns->bacct == NULL) {
+		acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
+		if (acct == NULL) {
+			filp_close(file, NULL);
+			return -ENOMEM;
+		}
+	}
+
 	error = security_acct(file);
 	if (error) {
+		kfree(acct);
 		filp_close(file, NULL);
 		return error;
 	}
 
 	spin_lock(&acct_lock);
-	mnt_pin(file->f_path.mnt);
-	acct_file_reopen(&acct_globals, file);
+	if (ns->bacct == NULL) {
+		ns->bacct = acct;
+		acct = NULL;
+	}
+
+	mnt = file->f_path.mnt;
+	mnt_pin(mnt);
+	acct_file_reopen(ns->bacct, file, ns);
 	spin_unlock(&acct_lock);
 
-	mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
+	mntput(mnt); /* it's pinned, now give up active reference */
+	kfree(acct);
 
 	return 0;
 }
@@ -256,7 +279,7 @@ static int acct_on(char *name)
  * should be written. If the filename is NULL, accounting will be
  * shutdown.
  */
-asmlinkage long sys_acct(const char __user *name)
+SYSCALL_DEFINE1(acct, const char __user *, name)
 {
 	int error;
 
@@ -270,10 +293,16 @@ asmlinkage long sys_acct(const char __user *name)
 		error = acct_on(tmp);
 		putname(tmp);
 	} else {
+		struct bsd_acct_struct *acct;
+
+		acct = task_active_pid_ns(current)->bacct;
+		if (acct == NULL)
+			return 0;
+
 		error = security_acct(NULL);
 		if (!error) {
 			spin_lock(&acct_lock);
-			acct_file_reopen(&acct_globals, NULL);
+			acct_file_reopen(acct, NULL, NULL);
 			spin_unlock(&acct_lock);
 		}
 	}
@@ -289,9 +318,15 @@ asmlinkage long sys_acct(const char __user *name)
  */
 void acct_auto_close_mnt(struct vfsmount *m)
 {
+	struct bsd_acct_struct *acct;
+
 	spin_lock(&acct_lock);
-	if (acct_globals.file && acct_globals.file->f_path.mnt == m)
-		acct_file_reopen(&acct_globals, NULL);
+restart:
+	list_for_each_entry(acct, &acct_list, list)
+		if (acct->file && acct->file->f_path.mnt == m) {
+			acct_file_reopen(acct, NULL, NULL);
+			goto restart;
+		}
 	spin_unlock(&acct_lock);
 }
 
@@ -304,10 +339,29 @@ void acct_auto_close_mnt(struct vfsmount *m)
  */
 void acct_auto_close(struct super_block *sb)
 {
+	struct bsd_acct_struct *acct;
+
+	spin_lock(&acct_lock);
+restart:
+	list_for_each_entry(acct, &acct_list, list)
+		if (acct->file && acct->file->f_path.mnt->mnt_sb == sb) {
+			acct_file_reopen(acct, NULL, NULL);
+			goto restart;
+		}
+	spin_unlock(&acct_lock);
+}
+
+void acct_exit_ns(struct pid_namespace *ns)
+{
+	struct bsd_acct_struct *acct;
+
 	spin_lock(&acct_lock);
-	if (acct_globals.file &&
-	    acct_globals.file->f_path.mnt->mnt_sb == sb) {
-		acct_file_reopen(&acct_globals, NULL);
+	acct = ns->bacct;
+	if (acct != NULL) {
+		if (acct->file != NULL)
+			acct_file_reopen(acct, NULL, NULL);
+
+		kfree(acct);
 	}
 	spin_unlock(&acct_lock);
 }
@@ -437,13 +491,17 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	u64 run_time;
 	struct timespec uptime;
 	struct tty_struct *tty;
+	const struct cred *orig_cred;
+
+	/* Perform file operations on behalf of whoever enabled accounting */
+	orig_cred = override_creds(file->f_cred);
 
 	/*
 	 * First check to see if there is enough free_space to continue
 	 * the process accounting system.
 	 */
 	if (!check_free_space(acct, file))
-		return;
+		goto out;
 
 	/*
 	 * Fill the accounting struct with the needed info as recorded
@@ -478,15 +536,15 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	do_div(elapsed, AHZ);
 	ac.ac_btime = get_seconds() - elapsed;
 	/* we really need to bite the bullet and change layout */
-	ac.ac_uid = current->uid;
-	ac.ac_gid = current->gid;
+	ac.ac_uid = orig_cred->uid;
+	ac.ac_gid = orig_cred->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;
+	ac.ac_uid16 = ac.ac_uid;
+	ac.ac_gid16 = ac.ac_gid;
 #endif
 #if ACCT_VERSION==3
 	ac.ac_pid = task_tgid_nr_ns(current, ns);
@@ -496,7 +554,7 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 #endif
 
 	spin_lock_irq(&current->sighand->siglock);
-	tty = current->signal->tty;
+	tty = current->signal->tty;	/* Safe as we hold the siglock */
 	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
 	ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
 	ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
@@ -525,6 +583,8 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 			       sizeof(acct_t), &file->f_pos);
 	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
 	set_fs(fs);
+out:
+	revert_creds(orig_cred);
 }
 
 /**
@@ -579,33 +639,46 @@ void acct_collect(long exitcode, int group_dead)
 	spin_unlock_irq(&current->sighand->siglock);
 }
 
-/**
- * acct_process - now just a wrapper around do_acct_process
- *
- * handles process accounting for an exiting task
- */
-void acct_process(void)
+static void acct_process_in_ns(struct pid_namespace *ns)
 {
 	struct file *file = NULL;
-	struct pid_namespace *ns;
+	struct bsd_acct_struct *acct;
 
+	acct = ns->bacct;
 	/*
 	 * accelerate the common fastpath:
 	 */
-	if (!acct_globals.file)
+	if (!acct || !acct->file)
 		return;
 
 	spin_lock(&acct_lock);
-	file = acct_globals.file;
+	file = acct->file;
 	if (unlikely(!file)) {
 		spin_unlock(&acct_lock);
 		return;
 	}
 	get_file(file);
-	ns = get_pid_ns(acct_globals.ns);
 	spin_unlock(&acct_lock);
 
-	do_acct_process(&acct_globals, ns, file);
+	do_acct_process(acct, ns, file);
 	fput(file);
-	put_pid_ns(ns);
+}
+
+/**
+ * acct_process - now just a wrapper around acct_process_in_ns,
+ * which in turn is a wrapper around do_acct_process.
+ *
+ * handles process accounting for an exiting task
+ */
+void acct_process(void)
+{
+	struct pid_namespace *ns;
+
+	/*
+	 * This loop is safe lockless, since current is still
+	 * alive and holds its namespace, which in turn holds
+	 * its parent.
+	 */
+	for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
+		acct_process_in_ns(ns);
 }