[PATCH 2/2] commands: dmesg: support aborting dmesg output with ctrl-c

[Ahmad Fatoum]

dmesg output can get very long, especially if debug messages are
compiled in and the maximum number of retained log messages is
increased.

Therefore, follow what we do for other potentially long-running
commands and allow the user to abort it with ctrl+c.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 commands/dmesg.c        | 6 ++++--
 common/console_common.c | 6 +++++-
 include/linux/printk.h  | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/commands/dmesg.c b/commands/dmesg.c
index 83410234e1d6..8a60f075076e 100644
--- a/commands/dmesg.c
+++ b/commands/dmesg.c
@@ -76,7 +76,7 @@ static unsigned dmesg_get_levels(const char *__args)
 
 static int do_dmesg(int argc, char *argv[])
 {
-	int opt, i;
+	int opt, ret, i;
 	int delete_buf = 0, emit = 0;
 	unsigned flags = 0, levels = 0;
 	char *set = NULL;
@@ -148,7 +148,9 @@ static int do_dmesg(int argc, char *argv[])
 		return 0;
 	}
 
-	log_print(flags, levels);
+	ret = log_print(flags, levels);
+	if (ret)
+		return 1;
 
 	if (delete_buf)
 		log_clean(10);
diff --git a/common/console_common.c b/common/console_common.c
index d25fb0dc5dde..631756e4800c 100644
--- a/common/console_common.c
+++ b/common/console_common.c
@@ -208,7 +208,7 @@ int log_writefile(const char *filepath)
 	return ret < 0 ? ret : nbytes;
 }
 
-void log_print(unsigned flags, unsigned levels)
+int log_print(unsigned flags, unsigned levels)
 {
 	struct log_entry *log;
 	unsigned long last = 0;
@@ -219,6 +219,8 @@ void log_print(unsigned flags, unsigned levels)
 
 		if (levels && !(levels & (1 << log->level)))
 			continue;
+		if (ctrlc())
+			return -EINTR;
 
 		if (!(flags & (BAREBOX_LOG_PRINT_RAW | BAREBOX_LOG_PRINT_TIME
 			       | BAREBOX_LOG_DIFF_TIME)))
@@ -247,6 +249,8 @@ void log_print(unsigned flags, unsigned levels)
 
 		printf("%s", log->msg);
 	}
+
+	return 0;
 }
 
 int printf(const char *fmt, ...)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 0e9604bbe967..07403ea60cb7 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -189,7 +189,7 @@ extern void log_clean(unsigned int limit);
 #define BAREBOX_LOG_PRINT_TIME		BIT(0)
 
 int log_writefile(const char *filepath);
-void log_print(unsigned flags, unsigned levels);
+int log_print(unsigned flags, unsigned levels);
 
 struct va_format {
 	const char *fmt;
-- 
2.39.2