netdev - [PATCH bpf-next 02/11] bpfilter: Add logging facility

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Message-Id: <20210517225308.720677-3-me@ubique.spb.ru>
Date:   Tue, 18 May 2021 02:52:59 +0400
From:   Dmitrii Banshchikov <me@...que.spb.ru>
To:     bpf@...r.kernel.org
Cc:     Dmitrii Banshchikov <me@...que.spb.ru>, ast@...nel.org,
        davem@...emloft.net, daniel@...earbox.net, andrii@...nel.org,
        kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org,
        netdev@...r.kernel.org, rdna@...com
Subject: [PATCH bpf-next 02/11] bpfilter: Add logging facility

There are three logging levels for messages: FATAL, NOTICE and DEBUG.
When a message is logged with FATAL level it results in bpfilter
usermode helper termination.

Introduce struct context to avoid use of global objects and store there
the logging parameters: log level and log sink.

Signed-off-by: Dmitrii Banshchikov <me@...que.spb.ru>
---
 net/bpfilter/Makefile  |  2 +-
 net/bpfilter/bflog.c   | 29 +++++++++++++++++++++++++++++
 net/bpfilter/bflog.h   | 24 ++++++++++++++++++++++++
 net/bpfilter/context.h | 16 ++++++++++++++++
 4 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 net/bpfilter/bflog.c
 create mode 100644 net/bpfilter/bflog.h
 create mode 100644 net/bpfilter/context.h

diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index cdac82b8c53a..874d5ef6237d 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -4,7 +4,7 @@
 #
 
 userprogs := bpfilter_umh
-bpfilter_umh-objs := main.o
+bpfilter_umh-objs := main.o bflog.o
 userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
 
 ifeq ($(CONFIG_BPFILTER_UMH), y)
diff --git a/net/bpfilter/bflog.c b/net/bpfilter/bflog.c
new file mode 100644
index 000000000000..2752e39060e4
--- /dev/null
+++ b/net/bpfilter/bflog.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#define _GNU_SOURCE
+
+#include "bflog.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "context.h"
+
+void bflog(struct context *ctx, int level, const char *fmt, ...)
+{
+	if (ctx->log_file &&
+	    (level == BFLOG_LEVEL_FATAL || (level & ctx->log_level))) {
+		va_list va;
+
+		va_start(va, fmt);
+		vfprintf(ctx->log_file, fmt, va);
+		va_end(va);
+	}
+
+	if (level == BFLOG_LEVEL_FATAL)
+		exit(EXIT_FAILURE);
+}
diff --git a/net/bpfilter/bflog.h b/net/bpfilter/bflog.h
new file mode 100644
index 000000000000..4ed12791cfa1
--- /dev/null
+++ b/net/bpfilter/bflog.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#ifndef NET_BPFILTER_BFLOG_H
+#define NET_BPFILTER_BFLOG_H
+
+struct context;
+
+#define BFLOG_IMPL(ctx, level, fmt, ...) bflog(ctx, level, "bpfilter: " fmt, ##__VA_ARGS__)
+
+#define BFLOG_LEVEL_FATAL (0)
+#define BFLOG_LEVEL_NOTICE (1)
+#define BFLOG_LEVEL_DEBUG (2)
+
+#define BFLOG_FATAL(ctx, fmt, ...)                                                                 \
+	BFLOG_IMPL(ctx, BFLOG_LEVEL_FATAL, "fatal error: " fmt, ##__VA_ARGS__)
+#define BFLOG_NOTICE(ctx, fmt, ...) BFLOG_IMPL(ctx, BFLOG_LEVEL_NOTICE, fmt, ##__VA_ARGS__)
+#define BFLOG_DEBUG(ctx, fmt, ...) BFLOG_IMPL(ctx, BFLOG_LEVEL_DEBUG, fmt, ##__VA_ARGS__)
+
+void bflog(struct context *ctx, int level, const char *fmt, ...);
+
+#endif // NET_BPFILTER_BFLOG_H
diff --git a/net/bpfilter/context.h b/net/bpfilter/context.h
new file mode 100644
index 000000000000..e85c97c3d010
--- /dev/null
+++ b/net/bpfilter/context.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#ifndef NET_BPFILTER_CONTEXT_H
+#define NET_BPFILTER_CONTEXT_H
+
+#include <stdio.h>
+
+struct context {
+	FILE *log_file;
+	int log_level;
+};
+
+#endif // NET_BPFILTER_CONTEXT_H
-- 
2.25.1