bpfilter will log to /dev/kmsg by default. Four different log levels are available. LOG_EMERG() will exit the usermode helper after logging.
Signed-off-by: Quentin Deslandes qde@naccy.de --- net/bpfilter/Makefile | 2 +- net/bpfilter/logger.c | 52 ++++++++++++++++++++++++++++ net/bpfilter/logger.h | 80 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 133 insertions(+), 1 deletion(-) create mode 100644 net/bpfilter/logger.c create mode 100644 net/bpfilter/logger.h
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile index cdac82b8c53a..8d9c726ba1a5 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 logger.o userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
ifeq ($(CONFIG_BPFILTER_UMH), y) diff --git a/net/bpfilter/logger.c b/net/bpfilter/logger.c new file mode 100644 index 000000000000..c256bfef7e6c --- /dev/null +++ b/net/bpfilter/logger.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2022 Meta Platforms, Inc. and affiliates. + */ + +#include "logger.h" + +#include <errno.h> + +static const char *log_file_path = "/dev/kmsg"; +static FILE *log_file; + +int logger_init(void) +{ + if (log_file) + return 0; + + log_file = fopen(log_file_path, "w"); + if (!log_file) + return -errno; + + if (setvbuf(log_file, 0, _IOLBF, 0)) + return -errno; + + return 0; +} + +void logger_set_file(FILE *file) +{ + log_file = file; +} + +FILE *logger_get_file(void) +{ + return log_file; +} + +int logger_clean(void) +{ + int r; + + if (!log_file) + return 0; + + r = fclose(log_file); + if (r == EOF) + return -errno; + + log_file = NULL; + + return 0; +} diff --git a/net/bpfilter/logger.h b/net/bpfilter/logger.h new file mode 100644 index 000000000000..c44739ec0069 --- /dev/null +++ b/net/bpfilter/logger.h @@ -0,0 +1,80 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2022 Meta Platforms, Inc. and affiliates. + */ + +#ifndef NET_BPFILTER_LOGGER_H +#define NET_BPFILTER_LOGGER_H + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> + +#define _BFLOG_IMPL(level, fmt, ...) \ + do { \ + typeof(level) __level = level; \ + if (logger_get_file()) { \ + fprintf(logger_get_file(), "<%d>bpfilter: " fmt "\n", \ + (__level), ##__VA_ARGS__); \ + } \ + if ((__level) == LOG_EMERG) \ + exit(EXIT_FAILURE); \ + } while (0) + +#define BFLOG_EMERG(fmt, ...) \ + _BFLOG_IMPL(LOG_KERN | LOG_EMERG, fmt, ##__VA_ARGS__) +#define BFLOG_ERR(fmt, ...) \ + _BFLOG_IMPL(LOG_KERN | LOG_ERR, fmt, ##__VA_ARGS__) +#define BFLOG_NOTICE(fmt, ...) \ + _BFLOG_IMPL(LOG_KERN | LOG_NOTICE, fmt, ##__VA_ARGS__) + +#ifdef DEBUG +#define BFLOG_DBG(fmt, ...) BFLOG_IMPL(LOG_KERN | LOG_DEBUG, fmt, ##__VA_ARGS__) +#else +#define BFLOG_DBG(fmt, ...) +#endif + +#define STRERR(v) strerror(abs(v)) + +/** + * logger_init() - Initialise logging facility. + * + * This function is used to open a file to write logs to (see @log_file_path). + * It must be called before using any logging macro, otherwise log messages + * will be discarded. + * + * Return: 0 on success, negative errno value on error. + */ +int logger_init(void); + +/** + * logger_set_file() - Set the FILE pointer to use to log messages. + * @file: new FILE * to the log file. + * + * This function won't check whether the FILE pointer is valid, nor whether + * a file is already opened, this is the responsibility of the caller. Once + * logger_set_file() returns, all new log messages will be printed to the + * FILE * provided. + */ +void logger_set_file(FILE *file); + +/** + * logger_get_file() - Returns a FILE * pointer to the log file. + * + * Return: pointer to the file to log to (as a FILE *), or NULL if the file + * is not valid. + */ +FILE *logger_get_file(void); + +/** + * logger_clean() - Close the log file. + * + * On success, the log file pointer will be NULL. If the function fails, + * the log file pointer remain unchanged and the file should be considered open. + * + * Return: 0 on success, negative errno value on error. + */ +int logger_clean(void); + +#endif // NET_BPFILTER_LOGGER_H