X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=drivers%2Ftty%2Ftty_io.c;h=1f9ee25b635e7196c6a0c464da5d8d91f88c59c8;hp=05085beb83dbe31b49679735530fa4a5a42b8882;hb=710dbb61210c0546cd1bfd9ebd0ad29207202d26;hpb=a84f6aa68e35a911c28e5871c87356dce3607b40

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 05085beb83db..1f9ee25b635e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -940,6 +940,14 @@ void start_tty(struct tty_struct *tty)
 
 EXPORT_SYMBOL(start_tty);
 
+/* We limit tty time update visibility to every 8 seconds or so. */
+static void tty_update_time(struct timespec *time)
+{
+	unsigned long sec = get_seconds();
+	if (abs(sec - time->tv_sec) & ~7)
+		time->tv_sec = sec;
+}
+
 /**
  *	tty_read	-	read method for tty device files
  *	@file: pointer to tty file
@@ -976,8 +984,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
 	else
 		i = -EIO;
 	tty_ldisc_deref(ld);
+
 	if (i > 0)
-		inode->i_atime = current_fs_time(inode->i_sb);
+		tty_update_time(&inode->i_atime);
+
 	return i;
 }
 
@@ -1079,8 +1089,8 @@ static inline ssize_t do_tty_write(
 		cond_resched();
 	}
 	if (written) {
-		struct inode *inode = file->f_path.dentry->d_inode;
-		inode->i_mtime = current_fs_time(inode->i_sb);
+               struct inode *inode = file->f_path.dentry->d_inode;
+		tty_update_time(&inode->i_mtime);
 		ret = written;
 	}
 out:
@@ -1212,9 +1222,9 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p)
  *
  *	Locking: None
  */
-static void tty_line_name(struct tty_driver *driver, int index, char *p)
+static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
 {
-	sprintf(p, "%s%d", driver->name, index + driver->name_base);
+	return sprintf(p, "%s%d", driver->name, index + driver->name_base);
 }
 
 /**
@@ -1584,6 +1594,7 @@ int tty_release(struct inode *inode, struct file *filp)
 	int	devpts;
 	int	idx;
 	char	buf[64];
+	long	timeout = 0;
 
 	if (tty_paranoia_check(tty, inode, "tty_release_dev"))
 		return 0;
@@ -1711,7 +1722,11 @@ int tty_release(struct inode *inode, struct file *filp)
 				    "active!\n", tty_name(tty, buf));
 		tty_unlock();
 		mutex_unlock(&tty_mutex);
-		schedule();
+		schedule_timeout_killable(timeout);
+		if (timeout < 120 * HZ)
+			timeout = 2 * timeout + 1;
+		else
+			timeout = MAX_SCHEDULE_TIMEOUT;
 	}
 
 	/*
@@ -1970,8 +1985,24 @@ got_driver:
 	if (!noctty &&
 	    current->signal->leader &&
 	    !current->signal->tty &&
-	    tty->session == NULL)
-		__proc_set_tty(current, tty);
+	    tty->session == NULL) {
+		/*
+		 * Don't let a process that only has write access to the tty
+		 * obtain the privileges associated with having a tty as
+		 * controlling terminal (being able to reopen it with full
+		 * access through /dev/tty, being able to perform pushback).
+		 * Many distributions set the group of all ttys to "tty" and
+		 * grant write-only access to all terminals for setgid tty
+		 * binaries, which should not imply full privileges on all ttys.
+		 *
+		 * This could theoretically break old code that performs open()
+		 * on a write-only file descriptor. In that case, it might be
+		 * necessary to also permit this if
+		 * inode_permission(inode, MAY_READ) == 0.
+		 */
+		if (filp->f_mode & FMODE_READ)
+			__proc_set_tty(current, tty);
+	}
 	spin_unlock_irq(&current->sighand->siglock);
 	tty_unlock();
 	mutex_unlock(&tty_mutex);
@@ -2251,7 +2282,7 @@ static int fionbio(struct file *file, int __user *p)
  *		Takes ->siglock() when updating signal->tty
  */
 
-static int tiocsctty(struct tty_struct *tty, int arg)
+static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
 {
 	int ret = 0;
 	if (current->signal->leader && (task_session(current) == tty->session))
@@ -2284,6 +2315,13 @@ static int tiocsctty(struct tty_struct *tty, int arg)
 			goto unlock;
 		}
 	}
+
+	/* See the comment in tty_open(). */
+	if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
+		ret = -EPERM;
+		goto unlock;
+	}
+
 	proc_set_tty(current, tty);
 unlock:
 	mutex_unlock(&tty_mutex);
@@ -2436,6 +2474,28 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
 	return ret;
 }
 
+/**
+ *	tiocgetd	-	get line discipline
+ *	@tty: tty device
+ *	@p: pointer to user data
+ *
+ *	Retrieves the line discipline id directly from the ldisc.
+ *
+ *	Locking: waits for ldisc reference (in case the line discipline
+ *		is changing or the tty is being hungup)
+ */
+
+static int tiocgetd(struct tty_struct *tty, int __user *p)
+{
+	struct tty_ldisc *ld;
+	int ret;
+
+	ld = tty_ldisc_ref_wait(tty);
+	ret = put_user(ld->ops->num, p);
+	tty_ldisc_deref(ld);
+	return ret;
+}
+
 /**
  *	send_break	-	performed time break
  *	@tty: device to break on
@@ -2638,7 +2698,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		no_tty();
 		return 0;
 	case TIOCSCTTY:
-		return tiocsctty(tty, arg);
+		return tiocsctty(tty, file, arg);
 	case TIOCGPGRP:
 		return tiocgpgrp(tty, real_tty, p);
 	case TIOCSPGRP:
@@ -2646,7 +2706,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case TIOCGSID:
 		return tiocgsid(tty, real_tty, p);
 	case TIOCGETD:
-		return put_user(tty->ldisc->ops->num, (int __user *)p);
+		return tiocgetd(tty, p);
 	case TIOCSETD:
 		return tiocsetd(tty, p);
 	case TIOCVHANGUP:
@@ -3311,9 +3371,19 @@ static ssize_t show_cons_active(struct device *dev,
 		if (i >= ARRAY_SIZE(cs))
 			break;
 	}
-	while (i--)
-		count += sprintf(buf + count, "%s%d%c",
-				 cs[i]->name, cs[i]->index, i ? ' ':'\n');
+	while (i--) {
+		int index = cs[i]->index;
+		struct tty_driver *drv = cs[i]->device(cs[i], &index);
+
+		/* don't resolve tty0 as some programs depend on it */
+		if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
+			count += tty_line_name(drv, index, buf + count);
+		else
+			count += sprintf(buf + count, "%s%d",
+					 cs[i]->name, cs[i]->index);
+
+		count += sprintf(buf + count, "%c", i ? ' ':'\n');
+	}
 	console_unlock();
 
 	return count;