soc: apple: rtkit: Crop syslog messages

Crop trailing whitespace, null, and newline characters in syslog
messages received from coprocessors. Notably DCP sends its messages
including a trailing newline, so prior to this change we would end up
cluttering the kernel log by repeated newlines at the end of messages.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Reviewed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>

diff --git a/drivers/soc/apple/rtkit.c b/drivers/soc/apple/rtkit.c
index a02a44a745f63a98bf909faad8117299a6169e93..d9f19dc99da5e824b327c1a334e5d44e8f7c392b 100644 (file)
--- a/drivers/soc/apple/rtkit.c
+++ b/drivers/soc/apple/rtkit.c
@@ -409,11 +409,17 @@ static void apple_rtkit_syslog_rx_init(struct apple_rtkit *rtk, u64 msg)
                rtk->syslog_n_entries, rtk->syslog_msg_size);
 }
 
+static bool should_crop_syslog_char(char c)
+{
+       return c == '\n' || c == '\r' || c == ' ' || c == '\0';
+}
+
 static void apple_rtkit_syslog_rx_log(struct apple_rtkit *rtk, u64 msg)
 {
        u8 idx = msg & 0xff;
        char log_context[24];
        size_t entry_size = 0x20 + rtk->syslog_msg_size;
+       int msglen;
 
        if (!rtk->syslog_msg_buffer) {
                dev_warn(
@@ -446,7 +452,13 @@ static void apple_rtkit_syslog_rx_log(struct apple_rtkit *rtk, u64 msg)
                           rtk->syslog_msg_size);
 
        log_context[sizeof(log_context) - 1] = 0;
-       rtk->syslog_msg_buffer[rtk->syslog_msg_size - 1] = 0;
+
+       msglen = rtk->syslog_msg_size - 1;
+       while (msglen > 0 &&
+                  should_crop_syslog_char(rtk->syslog_msg_buffer[msglen - 1]))
+               msglen--;
+
+       rtk->syslog_msg_buffer[msglen] = 0;
        dev_info(rtk->dev, "RTKit: syslog message: %s: %s\n", log_context,
                 rtk->syslog_msg_buffer);