[PATCH] dmesg: add support for dumping log into file

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

We already have a log_writefile() helper for dumping the log into a
file. Make it easily accessible via the shell by having a new
dmesg -o option call it.

There is nothing keeping us from extending the function to support flags
and levels like log_print does, but this can follow later if needed.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 commands/dmesg.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/commands/dmesg.c b/commands/dmesg.c
index 8a60f075076e..7982188cda6d 100644
--- a/commands/dmesg.c
+++ b/commands/dmesg.c
@@ -76,13 +76,17 @@ static unsigned dmesg_get_levels(const char *__args)
 
 static int do_dmesg(int argc, char *argv[])
 {
+	const char *outputfile = NULL;
 	int opt, ret, i;
 	int delete_buf = 0, emit = 0;
 	unsigned flags = 0, levels = 0;
 	char *set = NULL;
 
-	while ((opt = getopt(argc, argv, "ctderl:n:")) > 0) {
+	while ((opt = getopt(argc, argv, "o:ctderl:n:")) > 0) {
 		switch (opt) {
+		case 'o':
+			outputfile = optarg;
+			break;
 		case 'c':
 			delete_buf = 1;
 			break;
@@ -111,6 +115,12 @@ static int do_dmesg(int argc, char *argv[])
 		}
 	}
 
+	if (outputfile) {
+		if (flags || levels)
+			return COMMAND_ERROR_USAGE;
+		return log_writefile(outputfile);
+	}
+
 	if (set) {
 		int level = str_to_loglevel(set);
 
@@ -166,6 +176,7 @@ BAREBOX_CMD_HELP_TEXT("Known debug loglevels are: emerg, alert, crit, err, warn,
 BAREBOX_CMD_HELP_TEXT("vdebug")
 BAREBOX_CMD_HELP_TEXT("")
 BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-o <file>",	"Output all log to given file (conflicts with -tdlr)")
 BAREBOX_CMD_HELP_OPT ("-c",		"Delete messages after printing them")
 BAREBOX_CMD_HELP_OPT ("-d",		"Show a time delta to the last message")
 BAREBOX_CMD_HELP_OPT ("-e <msg>",	"Emit a log message")
-- 
2.39.5