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Rather than storing the iterator information in the registered kmsg_dumper structure, create a separate iterator structure. The kmsg_dump_iter structure can reside on the stack of the caller, thus allowing lockless use of the kmsg_dump functions. Update code that accesses the kernel logs using the kmsg_dumper structure to use the new kmsg_dump_iter structure. For kmsg_dumpers, this also means adding a call to kmsg_dump_rewind() to initialize the iterator. All this is in preparation for removal of @logbuf_lock. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> # pstore Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de
60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kmsg_dump.h>
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#include <linux/spinlock.h>
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#include <linux/console.h>
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#include <linux/string.h>
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#include <shared/init.h>
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#include <shared/kern.h>
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#include <os.h>
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static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
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enum kmsg_dump_reason reason)
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{
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static struct kmsg_dump_iter iter;
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static DEFINE_SPINLOCK(lock);
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static char line[1024];
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struct console *con;
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unsigned long flags;
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size_t len = 0;
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/* only dump kmsg when no console is available */
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if (!console_trylock())
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return;
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for_each_console(con) {
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if(strcmp(con->name, "tty") == 0 &&
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(con->flags & (CON_ENABLED | CON_CONSDEV)) != 0) {
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break;
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}
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}
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console_unlock();
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if (con)
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return;
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if (!spin_trylock_irqsave(&lock, flags))
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return;
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kmsg_dump_rewind(&iter);
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printf("kmsg_dump:\n");
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while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) {
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line[len] = '\0';
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printf("%s", line);
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}
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spin_unlock_irqrestore(&lock, flags);
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}
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static struct kmsg_dumper kmsg_dumper = {
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.dump = kmsg_dumper_stdout
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};
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int __init kmsg_dumper_stdout_init(void)
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{
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return kmsg_dump_register(&kmsg_dumper);
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}
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__uml_postsetup(kmsg_dumper_stdout_init);
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