[GitHub] [incubator-nuttx] fjpanag commented on a change in pull request #3842: Added automatic log rotation, when log file is opened.

[GitBox <gi...@apache.org>]

fjpanag commented on a change in pull request #3842:
URL: https://github.com/apache/incubator-nuttx/pull/3842#discussion_r645049787



##########
File path: drivers/syslog/syslog_filechannel.c
##########
@@ -50,6 +54,62 @@
 
 FAR static struct syslog_channel_s *g_syslog_file_channel;
 
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+#ifdef CONFIG_SYSLOG_FILE_ROTATE
+static void log_rotate(FAR const char *log_file)
+{
+  int fd;
+  off_t size;
+  struct stat f_stat;
+  char * backup_file;
+
+  /* Get the size of the current log file. */
+
+  fd = open(log_file, O_RDONLY);
+  if (fd < 0)
+    {
+      return;
+    }
+
+  fstat(fd, &f_stat);
+  size = f_stat.st_size;
+  close(fd);
+
+  /* If it does not exceed the limit we are OK. */
+
+  if (size < CONFIG_SYSLOG_FILE_SIZE_LIMIT)
+    {
+      return;
+    }
+
+  /* Construct the backup file name. */
+
+  backup_file = malloc(strlen(log_file) + 3);
+  if (backup_file == NULL)
+    {
+      return;
+    }
+
+  sprintf(backup_file, "%s.0", log_file);
+
+  /* Delete any old backup files. */
+
+  if (access(backup_file, F_OK) == 0)
+    {
+      remove(backup_file);
+    }
+
+  /* Rotate the log. */
+
+  rename(log_file, backup_file);
+
+  free(backup_file);

Review comment:
       It is still a rotation, it just happens that there is only one rotation available. :)
   
   Renaming this as "backup" would imply that this is a backup functionality. Which is not.  
   A backup would also keep the original file in place, while here it is deleted.
   
   This can be very easily be extended to keep multiple rotations, instead of only one.  
   I have done this in the past, and I can easily add it to this implementation.
   
   But I intentionally left it out. Do we really need so many log files?  
   If you think so, I will add it tomorrow.




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