diff options
| author | Kay Sievers <kay@vrfy.org> | 2012-07-16 18:35:30 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-07-16 18:35:30 -0700 |
| commit | d39f3d77c9b1fe7cc33a14beb4a4849af0a4ac22 (patch) | |
| tree | bf3a4fd34aa850a5f30f966dfd98a40a424f6b9a /Documentation | |
| parent | 96efedf1491cdf0616e5e4fff0711cebf20f69c7 (diff) | |
kmsg - export "continuation record" flag to /dev/kmsg
In some cases we are forced to store individual records for a continuation
line print.
Export a flag to allow the external re-construction of the line. The flag
allows us to apply a similar logic externally which is used internally when
the console, /proc/kmsg or the syslog() output is printed.
$ cat /dev/kmsg
4,165,0,-;Free swap = 0kB
4,166,0,-;Total swap = 0kB
6,167,0,c;[
4,168,0,+;0
4,169,0,+;1
4,170,0,+;2
4,171,0,+;3
4,172,0,+;]
6,173,0,-;[0 1 2 3 ]
6,174,0,-;Console: colour VGA+ 80x25
6,175,0,-;console [tty0] enabled
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/dev-kmsg | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/Documentation/ABI/testing/dev-kmsg b/Documentation/ABI/testing/dev-kmsg index 281ecc5f970..7e7e07a82e0 100644 --- a/Documentation/ABI/testing/dev-kmsg +++ b/Documentation/ABI/testing/dev-kmsg @@ -58,16 +58,18 @@ Description: The /dev/kmsg character device node provides userspace access The output format consists of a prefix carrying the syslog prefix including priority and facility, the 64 bit message - sequence number and the monotonic timestamp in microseconds. - The values are separated by a ','. Future extensions might - add more comma separated values before the terminating ';'. - Unknown values should be gracefully ignored. + sequence number and the monotonic timestamp in microseconds, + and a flag field. All fields are separated by a ','. + + Future extensions might add more comma separated values before + the terminating ';'. Unknown fields and values should be + gracefully ignored. The human readable text string starts directly after the ';' and is terminated by a '\n'. Untrusted values derived from hardware or other facilities are printed, therefore - all non-printable characters in the log message are escaped - by "\x00" C-style hex encoding. + all non-printable characters and '\' itself in the log message + are escaped by "\x00" C-style hex encoding. A line starting with ' ', is a continuation line, adding key/value pairs to the log message, which provide the machine @@ -75,11 +77,11 @@ Description: The /dev/kmsg character device node provides userspace access userspace. Example: - 7,160,424069;pci_root PNP0A03:00: host bridge window [io 0x0000-0x0cf7] (ignored) + 7,160,424069,-;pci_root PNP0A03:00: host bridge window [io 0x0000-0x0cf7] (ignored) SUBSYSTEM=acpi DEVICE=+acpi:PNP0A03:00 - 6,339,5140900;NET: Registered protocol family 10 - 30,340,5690716;udevd[80]: starting version 181 + 6,339,5140900,-;NET: Registered protocol family 10 + 30,340,5690716,-;udevd[80]: starting version 181 The DEVICE= key uniquely identifies devices the following way: b12:8 - block dev_t @@ -87,4 +89,13 @@ Description: The /dev/kmsg character device node provides userspace access n8 - netdev ifindex +sound:card0 - subsystem:devname + The flags field carries '-' by default. A 'c' indicates a + fragment of a line. All following fragments are flagged with + '+'. Note, that these hints about continuation lines are not + neccessarily correct, and the stream could be interleaved with + unrelated messages, but merging the lines in the output + usually produces better human readable results. A similar + logic is used internally when messages are printed to the + console, /proc/kmsg or the syslog() syscall. + Users: dmesg(1), userspace kernel log consumers |