logger library and flag to run as daemon

3 files changed, 153 insertions, 0 deletions

diff --git a/lib/logger/Makefile b/lib/logger/Makefile
new file mode 100644
index 0000000..e5e7682
--- /dev/null
+++ b/lib/logger/Makefile
@@ -0,0 +1,54 @@
+# Copyright (c) 2026, Mr. Goblin
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+# all 3 values commented, using make's default or export CC
+# CC = cc -fno-caret-diagnostics -fno-color-diagnostics
+# CC = gcc -fno-diagnostics-show-caret -fdiagnostics-color=never
+# CC = gcc
+
+CFLAGS = -Wall -Wextra -pedantic -std=gnu89
+ARFLAGS = rcs
+
+# DEBUG = -g
+# DEBUG = -ggdb
+DEBUG =
+
+# STATIC = -static
+STATIC = -static -s
+# STATIC =
+
+PROG_NAME=liblogger
+VER=0.0.0
+DIST_NAME=$(PROG_NAME)-$(VER)
+
+
+MAINBINARIES = liblogger.a
+
+.SUFFIXES:
+.SUFFIXES: .c .o
+.PHONY: all clean dist ctags rebuild
+
+all: $(MAINBINARIES)
+
+ctags:
+	ctags *.c *.h *.cpp *.hpp
+
+dist:
+	git archive --format=tar --prefix=$(DIST_NAME)/ HEAD | \
+		bzip2 > $(DIST_NAME).tar.bz2
+
+clean:
+	rm -f $(MAINBINARIES) *.o *.test tags $(DIST_NAME)
+
+rebuild: clean all
+
+.c.o:
+	$(CC) $(DEBUG) $(CFLAGS) -c $< -o $@
+
+
+LIBLOGGER_OBJECTS = logger.o
+LIBLOGGER_LIBS = -lc
+
+liblogger.a: $(LIBLOGGER_OBJECTS)
+	$(AR) $(ARFLAGS) $@ $(LIBLOGGER_OBJECTS)
diff --git a/lib/logger/logger.c b/lib/logger/logger.c
new file mode 100644
index 0000000..64a6754
--- /dev/null
+++ b/lib/logger/logger.c
@@ -0,0 +1,78 @@
+#include <syslog.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include "logger.h"
+
+static int use_syslog = 0;
+
+void
+logger_init(const char *name, int daemon_flag)
+{
+	use_syslog = daemon_flag;
+	if (use_syslog)
+		openlog(name, LOG_PID, LOG_DAEMON);
+}
+
+void
+logger_close(void)
+{
+	if (use_syslog)
+		closelog();
+}
+
+void
+logger_log(enum logger_lvl level, const char *format, ...)
+{
+	int saved_errno = errno;
+	va_list vargs;
+	va_start(vargs, format);
+	if (use_syslog) {
+		switch (level) {
+		case log_lvl_info:
+			vsyslog(LOG_INFO, format, vargs);
+			break;
+		case log_lvl_warning:
+			vsyslog(LOG_WARNING, format, vargs);
+			break;
+		case log_lvl_err:
+			vsyslog(LOG_ERR, format, vargs);
+			break;
+		}
+	} else {
+		FILE *f = NULL;
+		switch (level) {
+		case log_lvl_info:
+			f = stdout;
+			fprintf(f, "[INFO] ");
+			break;
+		case log_lvl_warning:
+			f = stderr;
+			fprintf(f, "[WARNING] ");
+			break;
+		case log_lvl_err:
+			f = stderr;
+			fprintf(f, "[ERROR] ");
+			break;
+		default:
+			f = stderr;
+			fprintf(f, "[UNKNOWN] ");
+			break;
+		}
+		vfprintf(f, format, vargs);
+	}
+	errno = saved_errno;
+}
+
+void
+logger_perror(const char *s)
+{
+	int saved_errno = errno;
+	if (use_syslog) {
+		syslog(LOG_ERR, "%s: %s\n", s, strerror(errno));
+	} else {
+		perror(s);
+	}
+	errno = saved_errno;
+}
diff --git a/lib/logger/logger.h b/lib/logger/logger.h
new file mode 100644
index 0000000..6c9ed7d
--- /dev/null
+++ b/lib/logger/logger.h
@@ -0,0 +1,21 @@
+#ifndef LIB_LOGGER_H_SENTRY
+#define LIB_LOGGER_H_SENTRY
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum logger_lvl {
+	log_lvl_info,
+	log_lvl_warning,
+	log_lvl_err
+};
+
+void logger_init(const char *name, int daemon_flag);
+void logger_close(void);
+void logger_log(enum logger_lvl, const char *format, ...);
+void logger_perror(const char *s);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* LIB_LOGGER_H_SENTRY */