From 202a02af103a3aa0593009793dda86ba3ff8be96 Mon Sep 17 00:00:00 2001
From: Lukas Cone <lukas.kuzel.ch@gmail.com>
Date: Sun, 17 Apr 2022 23:07:14 +0200
Subject: [PATCH] fix: Crash on linux when opened file gets modified (#487)

---
 .../content/providers/file_provider.hpp       |  1 +
 .../content/providers/file_provider.cpp       | 22 +++++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/plugins/builtin/include/content/providers/file_provider.hpp b/plugins/builtin/include/content/providers/file_provider.hpp
index c2e337b95..177c29612 100644
--- a/plugins/builtin/include/content/providers/file_provider.hpp
+++ b/plugins/builtin/include/content/providers/file_provider.hpp
@@ -36,6 +36,7 @@ namespace hex::plugin::builtin::prv {
         void readRaw(u64 offset, void *buffer, size_t size) override;
         void writeRaw(u64 offset, const void *buffer, size_t size) override;
         [[nodiscard]] size_t getActualSize() const override;
+        [[nodiscard]] size_t getRealTimeSize();
 
         void save() override;
         void saveAs(const std::fs::path &path) override;
diff --git a/plugins/builtin/source/content/providers/file_provider.cpp b/plugins/builtin/source/content/providers/file_provider.cpp
index e3bded88a..2ec7b125f 100644
--- a/plugins/builtin/source/content/providers/file_provider.cpp
+++ b/plugins/builtin/source/content/providers/file_provider.cpp
@@ -65,7 +65,7 @@ namespace hex::plugin::builtin::prv {
     }
 
     void FileProvider::readRaw(u64 offset, void *buffer, size_t size) {
-        if ((offset + size) > this->getActualSize() || buffer == nullptr || size == 0)
+        if ((offset + size) > this->getRealTimeSize() || buffer == nullptr || size == 0)
             return;
 
         std::memcpy(buffer, reinterpret_cast<u8 *>(this->m_mappedFile) + offset, size);
@@ -135,6 +135,20 @@ namespace hex::plugin::builtin::prv {
         Provider::insert(offset, size);
     }
 
+    size_t FileProvider::getRealTimeSize() {
+#if defined(OS_LINUX)
+        if (struct stat newStats; (this->m_fileStatsValid = fstat(this->m_file, &newStats) == 0)) {
+            if (static_cast<off_t>(this->m_fileSize) != newStats.st_size ||
+                std::memcmp(&newStats.st_mtim, &this->m_fileStats.st_mtim, sizeof(newStats.st_mtim))) {
+                this->m_fileStats = newStats;
+                this->m_fileSize  = this->m_fileStats.st_size;
+                msync(this->m_mappedFile, this->m_fileStats.st_size, MS_INVALIDATE);
+            }
+        }
+#endif
+        return getActualSize();
+    }
+
     size_t FileProvider::getActualSize() const {
         return this->m_fileSize;
     }
@@ -171,7 +185,7 @@ namespace hex::plugin::builtin::prv {
 
         this->m_fileStatsValid = wstat(path.c_str(), &this->m_fileStats) == 0;
 
-        LARGE_INTEGER fileSize = { };
+        LARGE_INTEGER fileSize = {};
         this->m_file           = reinterpret_cast<HANDLE>(CreateFileW(path.c_str(), GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
 
         GetFileSizeEx(this->m_file, &fileSize);
@@ -236,10 +250,10 @@ namespace hex::plugin::builtin::prv {
         fileCleanup.release();
 
 #else
-        const auto &path = this->m_path.native();
+        const auto &path       = this->m_path.native();
         this->m_fileStatsValid = stat(path.c_str(), &this->m_fileStats) == 0;
 
-        int mmapprot     = PROT_READ | PROT_WRITE;
+        int mmapprot = PROT_READ | PROT_WRITE;
 
         this->m_file = ::open(path.c_str(), O_RDWR);
         if (this->m_file == -1) {