From f527c2c3880de6883b5b86ec8fedfb02a98651db Mon Sep 17 00:00:00 2001
From: cathery <dumdumcathery@gmail.com>
Date: Sat, 18 Apr 2020 15:19:02 +0300
Subject: [PATCH] Discard large log files on boot

---
 source/Sysmodule/source/config_handler.cpp |  1 +
 source/Sysmodule/source/log.cpp            | 26 +++++++++++++++++++++-
 source/Sysmodule/source/log.h              |  3 +++
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/source/Sysmodule/source/config_handler.cpp b/source/Sysmodule/source/config_handler.cpp
index fe281d9..4eb4ea1 100644
--- a/source/Sysmodule/source/config_handler.cpp
+++ b/source/Sysmodule/source/config_handler.cpp
@@ -306,6 +306,7 @@ namespace syscon::config
 
     Result Initialize()
     {
+        DiscardOldLogs();
         config::LoadAllConfigs();
         config::CheckForFileChanges();
         utimerCreate(&filecheckTimer, 1e+9L, TimerType_Repeating);
diff --git a/source/Sysmodule/source/log.cpp b/source/Sysmodule/source/log.cpp
index c14e94c..7634ffd 100644
--- a/source/Sysmodule/source/log.cpp
+++ b/source/Sysmodule/source/log.cpp
@@ -5,6 +5,30 @@
 
 static ams::os::Mutex printMutex;
 
+void DiscardOldLogs()
+{
+    std::scoped_lock printLock(printMutex);
+
+    FsFileSystem *fs = fsdevGetDeviceFileSystem("sdmc");
+    FsFile file;
+    s64 fileSize;
+
+    Result rc = fsFsOpenFile(fs, LOG_PATH, FsOpenMode_Read, &file);
+    if (R_FAILED(rc))
+        return;
+
+    rc = fsFileGetSize(&file, &fileSize);
+    fsFileClose(&file);
+    if (R_FAILED(rc))
+        return;
+
+    if (fileSize >= 0x20'000)
+    {
+        fsFsDeleteFile(fs, LOG_PATH);
+        WriteToLog("Deleted previous log file");
+    }
+}
+
 void WriteToLog(const char *fmt, ...)
 {
     std::scoped_lock printLock(printMutex);
@@ -14,7 +38,7 @@ void WriteToLog(const char *fmt, ...)
     timeGetCurrentTime(TimeType_LocalSystemClock, &ts);
     timeToCalendarTimeWithMyRule(ts, &caltime, nullptr);
 
-    FILE *fp = fopen(CONFIG_PATH "log.txt", "a");
+    FILE *fp = fopen(LOG_PATH, "a");
 
     //Print time
     fprintf(fp, "%04i-%02i-%02i %02i:%02i:%02i: ", caltime.year, caltime.month, caltime.day, caltime.hour, caltime.minute, caltime.second);
diff --git a/source/Sysmodule/source/log.h b/source/Sysmodule/source/log.h
index 647c0df..df09311 100644
--- a/source/Sysmodule/source/log.h
+++ b/source/Sysmodule/source/log.h
@@ -1,9 +1,12 @@
 #pragma once
 
+#define LOG_PATH CONFIG_PATH "log.txt"
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
+    void DiscardOldLogs();
 
     void WriteToLog(const char *fmt, ...) __attribute__((format(printf, 1, 2)));