xref: /linux-6.15/include/linux/kmsg_dump.h (revision 246f6f2f)
1 /*
2  * linux/include/kmsg_dump.h
3  *
4  * Copyright (C) 2009 Net Insight AB
5  *
6  * Author: Simon Kagstrom <[email protected]>
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License.  See the file COPYING in the main directory of this archive
10  * for more details.
11  */
12 #ifndef _LINUX_KMSG_DUMP_H
13 #define _LINUX_KMSG_DUMP_H
14 
15 #include <linux/errno.h>
16 #include <linux/list.h>
17 
18 /*
19  * Keep this list arranged in rough order of priority. Anything listed after
20  * KMSG_DUMP_OOPS will not be logged by default unless printk.always_kmsg_dump
21  * is passed to the kernel.
22  */
23 enum kmsg_dump_reason {
24 	KMSG_DUMP_UNDEF,
25 	KMSG_DUMP_PANIC,
26 	KMSG_DUMP_OOPS,
27 	KMSG_DUMP_EMERG,
28 	KMSG_DUMP_RESTART,
29 	KMSG_DUMP_HALT,
30 	KMSG_DUMP_POWEROFF,
31 };
32 
33 /**
34  * struct kmsg_dumper - kernel crash message dumper structure
35  * @list:	Entry in the dumper list (private)
36  * @dump:	Call into dumping code which will retrieve the data with
37  * 		through the record iterator
38  * @max_reason:	filter for highest reason number that should be dumped
39  * @registered:	Flag that specifies if this is already registered
40  */
41 struct kmsg_dumper {
42 	struct list_head list;
43 	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
44 	enum kmsg_dump_reason max_reason;
45 	bool active;
46 	bool registered;
47 
48 	/* private state of the kmsg iterator */
49 	u32 cur_idx;
50 	u32 next_idx;
51 	u64 cur_seq;
52 	u64 next_seq;
53 };
54 
55 #ifdef CONFIG_PRINTK
56 void kmsg_dump(enum kmsg_dump_reason reason);
57 
58 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
59 			char *line, size_t size, size_t *len);
60 
61 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
62 			  char *buf, size_t size, size_t *len);
63 
64 void kmsg_dump_rewind(struct kmsg_dumper *dumper);
65 
66 int kmsg_dump_register(struct kmsg_dumper *dumper);
67 
68 int kmsg_dump_unregister(struct kmsg_dumper *dumper);
69 #else
70 static inline void kmsg_dump(enum kmsg_dump_reason reason)
71 {
72 }
73 
74 static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
75 				const char *line, size_t size, size_t *len)
76 {
77 	return false;
78 }
79 
80 static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
81 					char *buf, size_t size, size_t *len)
82 {
83 	return false;
84 }
85 
86 static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
87 {
88 }
89 
90 static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
91 {
92 	return -EINVAL;
93 }
94 
95 static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
96 {
97 	return -EINVAL;
98 }
99 #endif
100 
101 #endif /* _LINUX_KMSG_DUMP_H */
102