From c7d33e18995f7286cde9db77db43aff014c78940 Mon Sep 17 00:00:00 2001
From: Mrunal Patel <mrunalp@gmail.com>
Date: Mon, 25 Sep 2017 15:36:14 -0700
Subject: [PATCH] conmon: Re-open the log file to not exceed max log file size

Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
---
 conmon/conmon.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/conmon/conmon.c b/conmon/conmon.c
index 223a2a73..1232a0b8 100644
--- a/conmon/conmon.c
+++ b/conmon/conmon.c
@@ -134,6 +134,8 @@ static GOptionEntry opt_entries[] =
 
 #define CGROUP_ROOT "/sys/fs/cgroup"
 
+static int log_fd = -1;
+
 static ssize_t write_all(int fd, const void *buf, size_t count)
 {
 	size_t remaining = count;
@@ -336,6 +338,31 @@ static int write_k8s_log(int fd, stdpipe_t pipe, const char *buf, ssize_t buflen
 			}
 		}
 
+		/*
+		 * We re-open the log file if writing out the bytes will exceed the max
+		 * log size. We also reset the state so that the new file is started with
+		 * a timestamp.
+		 */
+		if ((opt_log_size_max > 0) && (bytes_written + bytes_to_be_written) > opt_log_size_max) {
+			ninfo("Creating new log file");
+			insert_newline = FALSE;
+			insert_timestamp = TRUE;
+			bytes_written = 0;
+
+			/* Close the existing fd */
+			close(fd);
+
+			/* Unlink the file */
+			if (unlink(opt_log_path) < 0) {
+				pexit("Failed to unlink log file");
+			}
+
+			/* Open the log path file again */
+			log_fd = open(opt_log_path, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0600);
+			if (log_fd < 0)
+				pexit("Failed to open log file");
+			fd = log_fd;
+		}
 
 		/* Output a newline */
 		if (insert_newline) {
@@ -511,7 +538,6 @@ static int conn_sock = -1;
 static int conn_sock_readable;
 static int conn_sock_writable;
 
-static int log_fd = -1;
 static int oom_event_fd = -1;
 static int attach_socket_fd = -1;
 static int console_socket_fd = -1;