From 312de68e259fe03d6df09f7c7f0f7271c2350532 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Fri, 13 Dec 2013 10:15:52 +0100
Subject: Add new log-rotate feature and error handling on file log opening.

---
 hugin.c | 31 ++++++++++++++++++++++++++++---
 hugin.h | 12 +++++++++++-
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/hugin.c b/hugin.c
index 9a7e7a1..cf72e5e 100644
--- a/hugin.c
+++ b/hugin.c
@@ -34,6 +34,7 @@
 #include <time.h>
 #include <string.h>
 #include <unistd.h>
+#include <stdlib.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -119,7 +120,8 @@ struct hug_config_t {
   int fd;
   int file_fd;
   int stdout_no_date;
-  mutex_t mutex; 
+  mutex_t mutex;
+  char *filename;
 #ifdef WITH_HUG_SYSLOG
   const char* syslog_host;
   int syslog_port;
@@ -132,6 +134,7 @@ struct hug_config_t {
   //#ifdef WITH_HUG_MUTEX
   MUTEX_INIT_VALUE, // mutex;
   //#endif
+  NULL, // filename
 #ifdef WITH_HUG_SYSLOG
   NULL, // syslog_host;
   541, // syslog_port;
@@ -226,8 +229,13 @@ hug_status_t hug_init(unsigned int flags, ...)
       break;
     case HUG_OPTION_FILENAME:
       if(hug_config.flags & HUG_FLAG_OUTPUT_TO_FILE) {
-        const char *filename = (const char*)va_arg(vl, char*);
-        hug_config.file_fd = open(filename, O_CREAT | O_RDWR, 0777);
+        hug_config.filename = strdup((const char*)va_arg(vl, char*));
+        hug_config.file_fd = open(hug_config.filename, O_CREAT | O_RDWR, 0777);
+        if(hug_config.file_fd == -1) {
+          fprintf(stderr, "Could not open logfile for writing: %s\n",
+                  hug_config.filename);
+          return HUG_STATUS_ERROR;
+        }
       }
       break;
 #ifdef WITH_HUG_SYSLOG
@@ -268,6 +276,7 @@ void hug_close()
 {
   if(hug_config.flags & HUG_FLAG_OUTPUT_TO_FILE) {
     if(hug_config.file_fd != -1) close(hug_config.file_fd);
+    if(hug_config.filename) free(hug_config.filename);
   }
 
 #ifdef WITH_HUG_SYSLOG
@@ -277,6 +286,22 @@ void hug_close()
   hug_mutex_close();
 }
 
+hug_status_t hugin_reopen_log()
+{
+  if((hug_config.flags & HUG_FLAG_OUTPUT_TO_FILE) == 0) return HUG_STATUS_OK;
+
+  close(hug_config.file_fd);
+  hug_config.file_fd = open(hug_config.filename, O_CREAT | O_RDWR, 0777);
+
+  if(hug_config.file_fd == -1) {
+    fprintf(stderr, "Could not re-open logfile for writing: %s\n",
+            hug_config.filename);
+    return HUG_STATUS_ERROR;
+  }
+
+  return HUG_STATUS_OK;
+}
+
 /*
 static unsigned int gettid()
 {
diff --git a/hugin.h b/hugin.h
index 8aabcf1..393ce1c 100644
--- a/hugin.h
+++ b/hugin.h
@@ -131,11 +131,21 @@ enum HUG_OPTION {
  * @param flags combination of HUG_FLAG values
  * @param ... list of options (type-value pairs,
  *        terminated with HUG_OPTION_END).
- * @return 0 on success, 1 on error.
+ * @return HUG_STATUS_OK on success, 1 on error.
  */
 hug_status_t hug_init(unsigned int flags, ...);
 void hug_close();
 
+/**
+ * Use this function if hugin is logging to a file and this file has just been
+ * rotated. Hugin will then close the filedescriptor to the file and open
+ * the a new file with the same name and location.
+ * Be aware that logrotate might need to create this new file first with
+ * the correct permissions in order for hugin to write to it.
+ * @return 0 on success. HUG_STATUS_ERROR on error (cannot open file).
+ */
+hug_status_t hugin_reopen_log();
+
 /**
  * Example of usage (use mutex protected calls, send output to file):
  *
-- 
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