xref: /linux-6.15/include/linux/kmsg_dump.h (revision b1f6f161)
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_SHUTDOWN,
29 	KMSG_DUMP_MAX
30 };
31 
32 /**
33  * struct kmsg_dumper - kernel crash message dumper structure
34  * @list:	Entry in the dumper list (private)
35  * @dump:	Call into dumping code which will retrieve the data with
36  * 		through the record iterator
37  * @max_reason:	filter for highest reason number that should be dumped
38  * @registered:	Flag that specifies if this is already registered
39  */
40 struct kmsg_dumper {
41 	struct list_head list;
42 	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
43 	enum kmsg_dump_reason max_reason;
44 	bool active;
45 	bool registered;
46 
47 	/* private state of the kmsg iterator */
48 	u32 cur_idx;
49 	u32 next_idx;
50 	u64 cur_seq;
51 	u64 next_seq;
52 };
53 
54 #ifdef CONFIG_PRINTK
55 void kmsg_dump(enum kmsg_dump_reason reason);
56 
57 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
58 			       char *line, size_t size, size_t *len);
59 
60 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
61 			char *line, size_t size, size_t *len);
62 
63 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
64 			  char *buf, size_t size, size_t *len);
65 
66 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
67 
68 void kmsg_dump_rewind(struct kmsg_dumper *dumper);
69 
70 int kmsg_dump_register(struct kmsg_dumper *dumper);
71 
72 int kmsg_dump_unregister(struct kmsg_dumper *dumper);
73 #else
74 static inline void kmsg_dump(enum kmsg_dump_reason reason)
75 {
76 }
77 
78 static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
79 					     bool syslog, const char *line,
80 					     size_t size, size_t *len)
81 {
82 	return false;
83 }
84 
85 static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
86 				const char *line, size_t size, size_t *len)
87 {
88 	return false;
89 }
90 
91 static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
92 					char *buf, size_t size, size_t *len)
93 {
94 	return false;
95 }
96 
97 static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
98 {
99 }
100 
101 static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
102 {
103 }
104 
105 static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
106 {
107 	return -EINVAL;
108 }
109 
110 static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
111 {
112 	return -EINVAL;
113 }
114 #endif
115 
116 #endif /* _LINUX_KMSG_DUMP_H */
117