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
10static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
11 struct kmsg_dump_detail *detail)
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_is_usable(con, flags: console_srcu_read_flags(con), use_atomic: true)) {
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: &iter);
46
47 printf("kmsg_dump:\n");
48 while (kmsg_dump_get_line(iter: &iter, syslog: true, line, size: sizeof(line), len: &len)) {
49 line[len] = '\0';
50 printf("%s", line);
51 }
52
53 spin_unlock_irqrestore(lock: &lock, flags);
54}
55
56static struct kmsg_dumper kmsg_dumper = {
57 .dump = kmsg_dumper_stdout
58};
59
60static int __init kmsg_dumper_stdout_init(void)
61{
62 return kmsg_dump_register(dumper: &kmsg_dumper);
63}
64
65__uml_postsetup(kmsg_dumper_stdout_init);
66

source code of linux/arch/um/kernel/kmsg_dump.c