xref: /linux-6.15/include/linux/kmsg_dump.h (revision e831e400)
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  * @active:	Flag that specifies if this is currently dumping
40  * @cur_seq:	Points to the oldest message to dump
41  * @next_seq:	Points after the newest message to dump
42  */
43 struct kmsg_dumper {
44 	struct list_head list;
45 	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
46 	enum kmsg_dump_reason max_reason;
47 	bool active;
48 	bool registered;
49 
50 	/* private state of the kmsg iterator */
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_nolock(struct kmsg_dumper *dumper, bool syslog,
59 			       char *line, size_t size, size_t *len);
60 
61 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
62 			char *line, size_t size, size_t *len);
63 
64 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
65 			  char *buf, size_t size, size_t *len);
66 
67 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
68 
69 void kmsg_dump_rewind(struct kmsg_dumper *dumper);
70 
71 int kmsg_dump_register(struct kmsg_dumper *dumper);
72 
73 int kmsg_dump_unregister(struct kmsg_dumper *dumper);
74 
75 const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason);
76 #else
77 static inline void kmsg_dump(enum kmsg_dump_reason reason)
78 {
79 }
80 
81 static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
82 					     bool syslog, const char *line,
83 					     size_t size, size_t *len)
84 {
85 	return false;
86 }
87 
88 static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
89 				const char *line, size_t size, size_t *len)
90 {
91 	return false;
92 }
93 
94 static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
95 					char *buf, size_t size, size_t *len)
96 {
97 	return false;
98 }
99 
100 static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
101 {
102 }
103 
104 static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
105 {
106 }
107 
108 static inline int kmsg_dump_register(struct kmsg_dumper *dumper)
109 {
110 	return -EINVAL;
111 }
112 
113 static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
114 {
115 	return -EINVAL;
116 }
117 
118 static inline const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason)
119 {
120 	return "Disabled";
121 }
122 #endif
123 
124 #endif /* _LINUX_KMSG_DUMP_H */
125