Improve error handling on persistence files

Also properly fsynced it, and the dir it's in.

Improve error handling on persistence files
Also properly fsynced it, and the dir it's in.
Wiebe Cazemier
1 parent bc502926
Showing 2 changed files with 41 additions and 3 deletions
persistencefile.cpp
persistencefile.h
@@ -25,6 +25,7 @@ License along with FlashMQ. If not, see &lt;https://www.gnu.org/licenses/&gt;.
 #include <stdexcept>
 #include <stdio.h>
 #include <cstring>
+#include <libgen.h>
  
 #include "utils.h"
 #include "logger.h"
@@ -39,11 +40,28 @@ PersistenceFile::PersistenceFile(const std::string &amp;filePath) :
     this->filePath = filePath;
     this->filePathTemp = formatString("%s.newfile.%s", filePath.c_str(), getSecureRandomString(8).c_str());
     this->filePathCorrupt = formatString("%s.corrupt.%s", filePath.c_str(), getSecureRandomString(8).c_str());
+
+    std::vector<char> d1(filePath.length() + 1, 0);
+    std::copy(filePath.begin(), filePath.end(), d1.begin());
+    this->dirPath = std::string(dirname(d1.data()));
 }
  
 PersistenceFile::~PersistenceFile()
 {
-    closeFile();
+    try
+    {
+        closeFile();
+    }
+    catch(std::exception &ex)
+    {
+        Logger::getInstance()->logf(LOG_WARNING, ex.what());
+    }
+
+    if (f != nullptr)
+    {
+        fclose(f); // fclose was already attempted and error handled if it was possible. In case an early fault happend, we need to still make sure.
+        f = nullptr;
+    }
  
     if (digestContext)
     {
@@ -105,7 +123,6 @@ void PersistenceFile::hashFile()
     fseek(f, MAGIC_STRING_LENGH, SEEK_SET);
  
     writeCheck(md_value, output_len, 1, f);
-    fflush(f);
 }
  
 void PersistenceFile::verifyHash()
@@ -325,18 +342,38 @@ void PersistenceFile::closeFile()
         return;
  
     if (openMode == FileMode::write)
+    {
         hashFile();
  
+        if (fflush(f) != 0)
+        {
+            std::string msg(strerror(errno));
+            throw std::runtime_error(formatString("Flush of '%s' failed: %s.", this->filePathTemp.c_str(), msg.c_str()));
+        }
+
+        fsync(f->_fileno);
+    }
+
     if (f != nullptr)
     {
-        fclose(f);
+        FILE *f2 = f;
         f = nullptr;
+
+        if (fclose(f2) < 0)
+        {
+            std::string msg(strerror(errno));
+            throw std::runtime_error(formatString("Close of '%s' failed: %s.", this->filePathTemp.c_str(), msg.c_str()));
+        }
     }
  
     if (openMode == FileMode::write && !filePathTemp.empty() && ! filePath.empty())
     {
         if (rename(filePathTemp.c_str(), filePath.c_str()) < 0)
             throw std::runtime_error(formatString("Saving '%s' failed: rename of temp file to target failed with: %s", filePath.c_str(), strerror(errno)));
+
+        int dir_fd = open(this->dirPath.c_str(), O_RDONLY);
+        fsync(dir_fd);
+        close(dir_fd);
     }
 }
  
@@ -46,6 +46,7 @@ class PersistenceFile
     std::string filePath;
     std::string filePathTemp;
     std::string filePathCorrupt;
+    std::string dirPath;
  
     EVP_MD_CTX *digestContext = nullptr;
     const EVP_MD *sha512 = EVP_sha512();