From: Łukasz Stelmach <l.stelmach@samsung.com>
Date: Wed, 15 Dec 2021 23:28:34 +0000 (+0100)
Subject: Discard data from stdio
X-Git-Tag: submit/tizen/20220105.151434~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6424c17351a31b45ac8e0b53b91163c74e9b9636;p=platform%2Fkernel%2Flinux-tizen-modules-source.git

Discard data from stdio

Accept and discard unstructured data coming from stdio.

This commit is mainly to make the later changes more readable.

Change-Id: I0428eef0b3f9517e14b8de282003436e5296b66d
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---

diff --git a/kernel/logger.c b/kernel/logger.c
index 853a862..b5a8d2b 100644
--- a/kernel/logger.c
+++ b/kernel/logger.c
@@ -616,11 +616,17 @@ static ssize_t do_write_log_from_user(struct logger_log *log,
 static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
 			 unsigned long nr_segs, loff_t ppos)
 {
-	struct logger_log *log = file_get_log(iocb->ki_filp);
+	struct file *file = iocb->ki_filp;
+	struct logger_writer *writer = file->private_data;
+	struct logger_log *log = file_get_log(file);
 	size_t orig;
 	struct logger_entry header;
 	struct timespec now;
 	ssize_t ret = 0;
+	bool from_stdio = false;
+
+	if (writer->tag && writer->prio >= 2)
+		from_stdio = true;
 
 	now = current_kernel_time();
 
@@ -638,35 +644,40 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
 
 	mutex_lock(&log->mutex);
 
-	orig = log->w_off;
+	/* Prepend messages from STDOUT and STDERR with a tag and prio */
+	if (from_stdio) {
+		return 0;
+	} else {
+		orig = log->w_off;
 
-	/*
-	 * Fix up any readers, pulling them forward to the first readable
-	 * entry after (what will be) the new write offset. We do this now
-	 * because if we partially fail, we can end up with clobbered log
-	 * entries that encroach on readable buffer.
-	 */
-	fix_up_readers(log, sizeof(struct logger_entry) + header.len);
+		/*
+		 * Fix up any readers, pulling them forward to the first readable
+		 * entry after (what will be) the new write offset. We do this now
+		 * because if we partially fail, we can end up with clobbered log
+		 * entries that encroach on readable buffer.
+		 */
+		fix_up_readers(log, sizeof(struct logger_entry) + header.len);
 
-	do_write_log(log, &header, sizeof(struct logger_entry));
+		do_write_log(log, &header, sizeof(struct logger_entry));
 
-	while (nr_segs-- > 0) {
-		size_t len;
-		ssize_t nr;
+		while (nr_segs-- > 0) {
+			size_t len;
+			ssize_t nr;
 
-		/* figure out how much of this vector we can keep */
-		len = min_t(size_t, iov->iov_len, header.len - ret);
+			/* figure out how much of this vector we can keep */
+			len = min_t(size_t, iov->iov_len, header.len - ret);
 
-		/* write out this segment's payload */
-		nr = do_write_log_from_user(log, iov->iov_base, len);
-		if (unlikely(nr < 0)) {
-			log->w_off = orig;
-			mutex_unlock(&log->mutex);
-			return nr;
-		}
+			/* write out this segment's payload */
+			nr = do_write_log_from_user(log, iov->iov_base, len);
+			if (unlikely(nr < 0)) {
+				log->w_off = orig;
+				mutex_unlock(&log->mutex);
+				return nr;
+			}
 
-		iov++;
-		ret += nr;
+			iov++;
+			ret += nr;
+		}
 	}
 
 	mutex_unlock(&log->mutex);