Hi,
With 21-rc3, syslogd (sysklogd package) stopped writing
messages to /dev/console anymore. In the log files i see:
May 25 11:14:19 core syslogd: /dev/console: Illegal seek
May 25 11:14:19 core syslogd 1.4.1: restart (remote reception).
And strace shows
# strace echo foo >/dev/console
write(1, "foo\n", 4) = -1 ESPIPE (Illegal seek)
close(1) = 0
munmap(0x40016000, 4096) = 0
write(2, "echo: ", 6echo: ) = 6
write(2, "write error", 11write error) = 11
write(2, "\n", 1) = 1
_exit(1) = ?
We all understand that /dev/console can't be seeked, but it shouldn't
be so strict in enforcing this or else syslogd and friends will fail
to work. Unfortunately Linux doesn't have a pwritev() to not update
the file pointer.
The checkin on linux-2.4.21-rc3/drivers/char/tty_io.c
+ /* Can't seek (pwrite) on ttys. */
+ if (ppos != &file->f_pos)
+ return -ESPIPE;
should not be there in my opinion.
Comments ?
Mitch
On Sun, May 25, 2003 at 12:22:14PM +0100, [email protected] wrote:
> The checkin on linux-2.4.21-rc3/drivers/char/tty_io.c
>
> + /* Can't seek (pwrite) on ttys. */
> + if (ppos != &file->f_pos)
> + return -ESPIPE;
>
> should not be there in my opinion.
s/not be/be not/
--- drivers/char/tty_io.c Sat May 17 11:14:02 2003
+++ /tmp/tty_io.c Sun May 25 07:37:37 2003
@@ -751,6 +751,10 @@
struct tty_struct * tty;
struct inode *inode = file->f_dentry->d_inode;
+ /* Can't seek (pwrite) on ttys. */
+ if (ppos != &file->f_pos)
+ return -ESPIPE;
+
/*
* For now, we redirect writes from /dev/console as
* well as /dev/tty0.
@@ -775,10 +779,6 @@
return res;
}
}
-
- /* Can't seek (pwrite) on ttys. */
- if (ppos != &file->f_pos)
- return -ESPIPE;
tty = (struct tty_struct *)file->private_data;
if (tty_paranoia_check(tty, inode->i_rdev, "tty_write"))
On Sun, May 25, 2003 at 12:39:12PM +0100, [email protected] wrote:
> On Sun, May 25, 2003 at 12:22:14PM +0100, [email protected] wrote:
> > The checkin on linux-2.4.21-rc3/drivers/char/tty_io.c
> >
> > + /* Can't seek (pwrite) on ttys. */
> > + if (ppos != &file->f_pos)
> > + return -ESPIPE;
> >
> > should not be there in my opinion.
>
> s/not be/be not/
Grrr.... Correct patch follows:
--- drivers/char/tty_io.c Sat May 17 11:14:02 2003
+++ /tmp/tty_io.c Sun May 25 07:49:08 2003
@@ -751,6 +751,10 @@
struct tty_struct * tty;
struct inode *inode = file->f_dentry->d_inode;
+ /* Can't seek (pwrite) on ttys. */
+ if (ppos != &file->f_pos)
+ return -ESPIPE;
+
/*
* For now, we redirect writes from /dev/console as
* well as /dev/tty0.
@@ -770,15 +774,11 @@
spin_unlock(&redirect_lock);
if (p) {
- ssize_t res = p->f_op->write(p, buf, count, ppos);
+ ssize_t res = p->f_op->write(p, buf, count, &p->f_pos);
fput(p);
return res;
}
}
-
- /* Can't seek (pwrite) on ttys. */
- if (ppos != &file->f_pos)
- return -ESPIPE;
tty = (struct tty_struct *)file->private_data;
if (tty_paranoia_check(tty, inode->i_rdev, "tty_write"))