From 3ca12815f557e8512f203b480db9067417a58b69 Mon Sep 17 00:00:00 2001
From: Babak Farrokhi <babak@farrokhi.net>
Date: Wed, 21 Oct 2015 18:04:46 +0330
Subject: [PATCH] - add timestamping support via log_tsprintf()

---
 logfile.c      | 43 ++++++++++++++++++++++++++++++++++---------
 logfile.h      |  2 ++
 logfile_test.c |  8 +++++---
 3 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/logfile.c b/logfile.c
index 02bdf8e..84446c1 100644
--- a/logfile.c
+++ b/logfile.c
@@ -98,21 +98,46 @@ log_reopen(log_t **log)
 void
 log_printf(const log_t *log, const char *format,...)
 {
+	if (!log_isopen(log))
+		return;
+
 	va_list args;
 	char *message;
+	char *newline = "\n";
 
-	/*
-	 * todo: add timestamp and \n example: "Oct 21 13:46:35 %s\n"
-	 */
+	va_start(args, format);
+	vasprintf(&message, format, args);
+	va_end(args);
 
-	if (log_isopen(log)) {
+	write(log->fd, message, strnlen(message, MAX_MSG_SIZE));
+	write(log->fd, newline, sizeof(*newline));
+}
 
-		va_start(args, format);
-		vasprintf(&message, format, args);
-		va_end(args);
+void
+log_tsprintf(const log_t *log, const char *format,...)
+{
+	if (!log_isopen(log))
+		return;
 
-		write(log->fd, message, strnlen(message, MAX_MSG_SIZE));
-	}
+	va_list args;
+	char *message;
+	char s_time[30];
+	time_t now;
+	struct tm *ltime;
+	size_t tsize;
+	char *newline = "\n";
+
+	va_start(args, format);
+	vasprintf(&message, format, args);
+	va_end(args);
+
+	now = time(NULL);
+	ltime = localtime(&now);
+	tsize = strftime(s_time, sizeof(s_time), "%Y-%m-%d %T %Z - ", ltime);
+
+	write(log->fd, s_time, tsize);
+	write(log->fd, message, strnlen(message, MAX_MSG_SIZE));
+	write(log->fd, newline, sizeof(*newline));
 }
 
 bool
diff --git a/logfile.h b/logfile.h
index b867fcd..189e8a8 100644
--- a/logfile.h
+++ b/logfile.h
@@ -40,6 +40,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
+#include <time.h>
 
 #define LOGPATH "/var/log"
 #define MAX_MSG_SIZE 65536
@@ -58,5 +59,6 @@ bool	log_isopen(const log_t *log);
 bool	log_verify(const log_t *log);
 void	log_reopen(log_t **log);
 void	log_printf(const log_t *log, const char *format,...);
+void	log_tsprintf(const log_t *log, const char *format,...);
 
 #endif					/* _LOGFILE_H */
diff --git a/logfile_test.c b/logfile_test.c
index a70ff96..087862c 100644
--- a/logfile_test.c
+++ b/logfile_test.c
@@ -42,20 +42,22 @@ main(void)
 	if ((lh = log_open("test.log", 0600)) == NULL) {
 		err(EX_IOERR, "Cannot open log file");
 	}
-
 	if (!log_verify(lh))
 		err(errno, "Failed to verify integrity of log file");
 
-	log_printf(lh, "opened file handle: %d , inode: %llu\n", lh->fd, lh->ino);
+	log_printf(lh, "opened file handle: %d , inode: %llu", lh->fd, lh->ino);
 	printf("logfile: %s, handle: %d, inode: %llu, mode: %d\n", lh->path, lh->fd, lh->ino, lh->mode);
 
 	log_reopen(&lh);
 	if (!log_verify(lh))
 		err(errno, "Failed to verify integrity of reopened log file");
 
-	log_printf(lh, "reopened file handle: %d , inode: %llu\n", lh->fd, lh->ino);
+	log_printf(lh, "reopened file handle: %d , inode: %llu", lh->fd, lh->ino);
 	printf("logfile: %s, handle: %d, inode: %llu, mode: %d\n", lh->path, lh->fd, lh->ino, lh->mode);
 
+	for (int i = 1; i <= 4; i++)
+		log_tsprintf(lh, "This is a time stamped message %d", i);
+
 	log_close(lh);
 
 	return 0;