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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-05 07:22:25 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-05 07:22:25 +0200 |
| commit | a754292348bf88ec6b55563eca4faba7dcfe2ae7 (patch) | |
| tree | e83a65dae3699223687c47f9c9a4d4b2d12ef14c /Documentation/ABI/testing/dev-kmsg | |
| parent | Merge branch 'parisc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/... (diff) | |
| parent | Merge branch 'for-5.9-console-return-codes' into for-linus (diff) | |
| download | linux-a754292348bf88ec6b55563eca4faba7dcfe2ae7.tar.xz linux-a754292348bf88ec6b55563eca4faba7dcfe2ae7.zip | |
Merge tag 'printk-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Herbert Xu made printk header file self-contained.
- Andy Shevchenko and Sergey Senozhatsky cleaned up console->setup()
error handling.
- Andy Shevchenko did some cleanups (e.g. sparse warning) in vsprintf
code.
- Minor documentation updates.
* tag 'printk-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
lib/vsprintf: Force type of flags value for gfp_t
lib/vsprintf: Replace custom spec to print decimals with generic one
lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert()
printk: Make linux/printk.h self-contained
doc:kmsg: explicitly state the return value in case of SEEK_CUR
Replace HTTP links with HTTPS ones: vsprintf
hvc: unify console setup naming
console: Fix trivia typo 'change' -> 'chance'
console: Propagate error code from console ->setup()
tty: hvc: Return proper error code from console ->setup() hook
serial: sunzilog: Return proper error code from console ->setup() hook
serial: sunsab: Return proper error code from console ->setup() hook
mips: Return proper error code from console ->setup() hook
Diffstat (limited to 'Documentation/ABI/testing/dev-kmsg')
| -rw-r--r-- | Documentation/ABI/testing/dev-kmsg | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/dev-kmsg b/Documentation/ABI/testing/dev-kmsg index f307506eb54c..3c0bb76e3417 100644 --- a/Documentation/ABI/testing/dev-kmsg +++ b/Documentation/ABI/testing/dev-kmsg @@ -56,6 +56,17 @@ Description: The /dev/kmsg character device node provides userspace access seek after the last record available at the time the last SYSLOG_ACTION_CLEAR was issued. + Other seek operations or offsets are not supported because of + the special behavior this device has. The device allows to read + or write only whole variable length messages (records) that are + stored in a ring buffer. + + Because of the non-standard behavior also the error values are + non-standard. -ESPIPE is returned for non-zero offset. -EINVAL + is returned for other operations, e.g. SEEK_CUR. This behavior + and values are historical and could not be modified without the + risk of breaking userspace. + 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, |