Lines Matching refs:the
6 to the kernel's printk buffer.
9 Every write() to the opened device node places a log entry in
10 the kernel's printk buffer.
13 carries the syslog priority and facility. The single decimal
14 prefix number is composed of the 3 lowest bits being the syslog
15 priority and the higher bits the syslog facility number.
17 If no prefix is given, the priority number is the default kernel
18 log priority and the facility number is set to LOG_USER (1). It
19 is not possible to inject messages from userspace with the
20 facility number LOG_KERN (0), to make sure that the origin of
21 the messages can always be reliably determined.
23 Accessing the buffer:
24 Every read() from the opened device node receives one record
25 of the kernel's printk buffer.
28 first message in the buffer; there is no kernel-internal
29 persistent state; many readers can concurrently open the device
32 Every read() will receive the next available record. If no more
36 Messages in the record ring buffer get overwritten as whole,
39 In case messages get overwritten in the circular buffer while
40 the device is kept open, the next read() will return -EPIPE,
41 and the seek position be updated to the next available record.
44 Unlike the classic syslog() interface, the 64 bit record
45 sequence numbers allow to calculate the amount of lost
46 messages, in case the buffer gets overwritten. And they allow
47 to reconnect to the buffer and reconstruct the read position
48 if needed, without limiting the interface to a single reader.
50 The device supports seek with the following parameters:
52 seek to the first entry in the buffer
54 seek after the last entry in the buffer
56 seek after the last record available at the time
57 the last SYSLOG_ACTION_CLEAR was issued.
59 The output format consists of a prefix carrying the syslog
60 prefix including priority and facility, the 64 bit message
61 sequence number and the monotonic timestamp in microseconds,
65 the terminating ';'. Unknown fields and values should be
68 The human readable text string starts directly after the ';'
71 all non-printable characters and '\' itself in the log message
75 key/value pairs to the log message, which provide the machine
76 readable context of the message, for reliable processing in
86 The DEVICE= key uniquely identifies devices the following way:
95 necessarily correct, and the stream could be interleaved with
96 unrelated messages, but merging the lines in the output
98 logic is used internally when messages are printed to the
99 console, /proc/kmsg or the syslog() syscall.
103 console support is enabled, the in-kernel concatenation is
105 the log consumer performs concatenation, the end result
106 should be the same. In the future, the in-kernel concatenation