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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-23 08:14:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-23 08:14:12 -0700
commit6c2754c28f2388a276fe21edde826f2113c8f60e (patch)
treecfb966a1bbe36f10a7f55d0e38d34dfb275b9992 /Documentation/filesystems
parentab34c02afeafd047a831e6fe2a4dd875ce86bee0 (diff)
Revert "tty: Add a new file /proc/tty/consoles"
This reverts commit f4a3e0bceb57466c31757f25e4e0ed108d1299ec. Jiri Sladby points out that the tty structure we're using may already be gone, and Al Viro doesn't hold back in complaining about the random loading of 'filp->private_data' which doesn't have to be a pointer at all, nor does checking the magic field for TTY_MAGIC prove anything. Belated review by Al: "a) global variable depending on stdin of the last opener? Affecting output of read(2)? Really? b) iterator is broken; list should be locked in ->start(), unlocked in ->stop() and *NOT* unlocked/relocked in ->next() c) ->show() ought to do nothing in case of ->device == NULL, instead of skipping those in ->next()/->start() d) regardless of the merits of the bright idea about asterisk at that line in output *and* regardless of (a), the implementation is not only atrociously ugly, it's actually very likely to be a roothole. Verifying that Cthulhu knows what number happens to be address of a tty_struct by blindly dereferencing memory at that address... Ouch. Please revert that crap." And Christoph pipes in and NAK's the approach of walking fd tables etc too. So it's pretty unanimous. Noticed-by: Jri Slaby <jslaby@suse.cz> Requested-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Werner Fink <werner@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/proc.txt32
1 files changed, 0 insertions, 32 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 98223a67694..a6aca874088 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1075,7 +1075,6 @@ Table 1-11: Files in /proc/tty
drivers list of drivers and their usage
ldiscs registered line disciplines
driver/serial usage statistic and status of single tty lines
- consoles registered system console lines
..............................................................................
To see which tty's are currently in use, you can simply look into the file
@@ -1094,37 +1093,6 @@ To see which tty's are currently in use, you can simply look into the file
/dev/tty /dev/tty 5 0 system:/dev/tty
unknown /dev/tty 4 1-63 console
-To see which character device lines are currently used for the system console
-/dev/console, you may simply look into the file /proc/tty/consoles:
-
- > cat /proc/tty/consoles
- tty0 -WU (ECp) 4:7
- ttyS0 -W- (Ep) 4:64
-
-The columns are:
-
- device name of the device
- operations R = can do read operations
- W = can do write operations
- U = can do unblank
- flags E = it is enabled
- C = it is prefered console
- B = it is primary boot console
- p = it is used for printk buffer
- b = it is not a TTY but a Braille device
- a = it is safe to use when cpu is offline
- * = it is standard input of the reading process
- major:minor major and minor number of the device separated by a colon
-
-If the reading process holds /dev/console open at the regular standard input
-stream the active device will be marked by an asterisk:
-
- > cat /proc/tty/consoles < /dev/console
- tty0 -WU (ECp*) 4:7
- ttyS0 -W- (Ep) 4:64
- > tty
- /dev/pts/3
-
1.8 Miscellaneous kernel statistics in /proc/stat
-------------------------------------------------