1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kmsg_dump.h>
3 #include <linux/spinlock.h>
4 #include <linux/console.h>
5 #include <linux/string.h>
6 #include <shared/init.h>
7 #include <shared/kern.h>
8 #include <os.h>
9 
kmsg_dumper_stdout(struct kmsg_dumper * dumper,enum kmsg_dump_reason reason)10 static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
11 				enum kmsg_dump_reason reason)
12 {
13 	static struct kmsg_dump_iter iter;
14 	static DEFINE_SPINLOCK(lock);
15 	static char line[1024];
16 	struct console *con;
17 	unsigned long flags;
18 	size_t len = 0;
19 	int cookie;
20 
21 	/*
22 	 * If no consoles are available to output crash information, dump
23 	 * the kmsg buffer to stdout.
24 	 */
25 
26 	cookie = console_srcu_read_lock();
27 	for_each_console_srcu(con) {
28 		/*
29 		 * The ttynull console and disabled consoles are ignored
30 		 * since they cannot output. All other consoles are
31 		 * expected to output the crash information.
32 		 */
33 		if (strcmp(con->name, "ttynull") != 0 &&
34 		    (console_srcu_read_flags(con) & CON_ENABLED)) {
35 			break;
36 		}
37 	}
38 	console_srcu_read_unlock(cookie);
39 	if (con)
40 		return;
41 
42 	if (!spin_trylock_irqsave(&lock, flags))
43 		return;
44 
45 	kmsg_dump_rewind(&iter);
46 
47 	printf("kmsg_dump:\n");
48 	while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) {
49 		line[len] = '\0';
50 		printf("%s", line);
51 	}
52 
53 	spin_unlock_irqrestore(&lock, flags);
54 }
55 
56 static struct kmsg_dumper kmsg_dumper = {
57 	.dump = kmsg_dumper_stdout
58 };
59 
kmsg_dumper_stdout_init(void)60 int __init kmsg_dumper_stdout_init(void)
61 {
62 	return kmsg_dump_register(&kmsg_dumper);
63 }
64 
65 __uml_postsetup(kmsg_dumper_stdout_init);
66