This code fixes the errors from owasp-modsecurity#2304

Signed-off-by: Kasumi <kasumi@kitsune.exposed>

Author: akama-aka

src/audit_log/writer/parallel.h

@@ -40,6 +40,7 @@ class Parallel : public Writer {
     bool init(std::string *error) override;
     bool write(Transaction *transaction, int parts,
         std::string *error) override;
+    bool reopen(std::string *error) override;
 
 
     /**

src/rules_set.cc

@@ -325,6 +325,25 @@ extern "C" void msc_rules_error_cleanup(const char *error) {
     free((void*) error);
 }
 
+extern "C" int msc_rules_reopen_audit_log(RulesSet *rules, const char **error) {
+    bool succeeded = true;
+    std::string errorStr;
+
+    if (rules->m_auditLog != NULL) {
+        succeeded = rules->m_auditLog->reopen(&errorStr);
+    }
+
+    if (!succeeded) {
+        if (!errorStr.empty()) {
+            *error = strdup(errorStr.c_str());
+        } else {
+            // Guarantee an error message is always assigned in the event of a failure
+            *error = strdup("Unknown error reopening audit log");
+        }
+    }
+
+    return succeeded ? 0 : -1;
+}
 
 extern "C" int msc_rules_cleanup(RulesSet *rules) {
     delete rules;

src/utils/shared_files.cc

@@ -14,7 +14,7 @@
  */
 
 #include "src/utils/shared_files.h"
-
+#include <cstring>
 #include <fcntl.h>
 #ifdef WIN32
 #include <algorithm>
@@ -101,6 +101,23 @@ void SharedFiles::close(const std::string& fileName) {
     }
 }
 
+bool SharedFiles::reopen(const std::string& fileName, std::string *error) {
+    auto it = m_handlers.find(fileName);
+    if (it == m_handlers.end()) {
+        return open(fileName, error);
+    }
+
+    FILE* new_fp = fopen(fileName.c_str(), "a+");
+    if (new_fp == nullptr) {
+        error->assign("Failed to reopen file: " + fileName + " - " + strerror(errno));
+        return false;
+    }
+
+    fclose(it->second.fp);
+    it->second.fp = new_fp;
+
+    return true;
+}
 
 bool SharedFiles::write(const std::string& fileName,
     const std::string &msg, std::string *error) {