xref: /linux-6.15/include/linux/kmsg_dump.h (revision 6d3cf962)
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 };
30 
31 /**
32  * struct kmsg_dumper - kernel crash message dumper structure
33  * @list:	Entry in the dumper list (private)
34  * @dump:	Call into dumping code which will retrieve the data with
35  * 		through the record iterator
36  * @max_reason:	filter for highest reason number that should be dumped
37  * @registered:	Flag that specifies if this is already registered
38  */
39 struct kmsg_dumper {
40 	struct list_head list;
41 	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
42 	enum kmsg_dump_reason max_reason;
43 	bool active;
44 	bool registered;
45 
46 	/* private state of the kmsg iterator */
47 	u32 cur_idx;
48 	u32 next_idx;
49 	u64 cur_seq;
50 	u64 next_seq;
51 };
52 
53 #ifdef CONFIG_PRINTK
54 void kmsg_dump(enum kmsg_dump_reason reason);
55 
56 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
57 			       char *line, size_t size, size_t *len);
58 
59 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
60 			char *line, size_t size, size_t *len);
61 
62 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
63 			  char *buf, size_t size, size_t *len);
64 
65 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
66 
67 void kmsg_dump_rewind(struct kmsg_dumper *dumper);
68 
69 int kmsg_dump_register(struct kmsg_dumper *dumper);
70 
71 int kmsg_dump_unregister(struct kmsg_dumper *dumper);
72 #else
73 static inline void kmsg_dump(enum kmsg_dump_reason reason)
74 {
75 }
76 
77 static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
78 					     bool syslog, const char *line,
79 					     size_t size, size_t *len)
80 {
81 	return false;
82 }
83 
84 static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
85 				const char *line, size_t size, size_t *len)
86 {
87 	return false;
88 }
89 
90 static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
91 					char *buf, size_t size, size_t *len)
92 {
93 	return false;
94 }
95 
96 static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
97 {
98 }
99 
100 static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
101 {
102 }
103 
104 static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
105 {
106 	return -EINVAL;
107 }
108 
109 static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
110 {
111 	return -EINVAL;
112 }
113 #endif
114 
115 #endif /* _LINUX_KMSG_DUMP_H */
116