Objectpos over limit: Avoid crash caused by sector over limit

[oweals/minetest.git] / src / filesys.cpp

diff --git a/src/filesys.cpp b/src/filesys.cpp
index 501f9ad6ca53f721f4d117b2a199bb6b2e251af9..bd8b94aff98ff86ebf2ca6a0a5383c4625fd8717 100644 (file)
--- a/src/filesys.cpp
+++ b/src/filesys.cpp
@@ -26,6 +26,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <fstream>
 #include "log.h"
 #include "config.h"
+#include "porting.h"
 
 namespace fs
 {
@@ -616,48 +617,51 @@ std::string RemoveRelativePathComponents(std::string path)
 {
        size_t pos = path.size();
        size_t dotdot_count = 0;
-       while(pos != 0){
+       while (pos != 0) {
                size_t component_with_delim_end = pos;
                // skip a dir delimiter
-               while(pos != 0 && IsDirDelimiter(path[pos-1]))
+               while (pos != 0 && IsDirDelimiter(path[pos-1]))
                        pos--;
                // strip a path component
                size_t component_end = pos;
-               while(pos != 0 && !IsDirDelimiter(path[pos-1]))
+               while (pos != 0 && !IsDirDelimiter(path[pos-1]))
                        pos--;
                size_t component_start = pos;
 
                std::string component = path.substr(component_start,
                                component_end - component_start);
                bool remove_this_component = false;
-               if(component == "."){
+               if (component == ".") {
                        remove_this_component = true;
-               }
-               else if(component == ".."){
+               } else if (component == "..") {
                        remove_this_component = true;
                        dotdot_count += 1;
-               }
-               else if(dotdot_count != 0){
+               } else if (dotdot_count != 0) {
                        remove_this_component = true;
                        dotdot_count -= 1;
                }
 
-               if(remove_this_component){
-                       while(pos != 0 && IsDirDelimiter(path[pos-1]))
+               if (remove_this_component) {
+                       while (pos != 0 && IsDirDelimiter(path[pos-1]))
                                pos--;
-                       path = path.substr(0, pos) + DIR_DELIM +
-                               path.substr(component_with_delim_end,
-                                               std::string::npos);
-                       pos++;
+                       if (component_start == 0) {
+                               // We need to remove the delemiter too
+                               path = path.substr(component_with_delim_end, std::string::npos);
+                       } else {
+                               path = path.substr(0, pos) + DIR_DELIM +
+                                       path.substr(component_with_delim_end, std::string::npos);
+                       }
+                       if (pos > 0)
+                               pos++;
                }
        }
 
-       if(dotdot_count > 0)
+       if (dotdot_count > 0)
                return "";
 
        // remove trailing dir delimiters
        pos = path.size();
-       while(pos != 0 && IsDirDelimiter(path[pos-1]))
+       while (pos != 0 && IsDirDelimiter(path[pos-1]))
                pos--;
        return path.substr(0, pos);
 }
@@ -698,22 +702,37 @@ bool safeWriteToFile(const std::string &path, const std::string &content)
                return false;
        }
 
+       bool rename_success = false;
+
        // Move the finished temporary file over the real file
 #ifdef _WIN32
+       // When creating the file, it can cause Windows Search indexer, virus scanners and other apps
+       // to query the file. This can make the move file call below fail.
+       // We retry up to 5 times, with a 1ms sleep between, before we consider the whole operation failed
+       int number_attempts = 0;
+       while (number_attempts < 5) {
+               rename_success = MoveFileEx(tmp_file.c_str(), path.c_str(),
+                               MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH);
+               if (rename_success)
+                       break;
+               sleep_ms(1);
+               ++number_attempts;
+       }
+#else
        // On POSIX compliant systems rename() is specified to be able to swap the
        // file in place of the destination file, making this a truly error-proof
        // transaction.
-       // However, on Windows, the target file has to be removed first.
-       remove(path.c_str());
+       rename_success = rename(tmp_file.c_str(), path.c_str()) == 0;
 #endif
-       if(rename(tmp_file.c_str(), path.c_str())) {
+       if (!rename_success) {
+               warningstream << "Failed to write to file: " << path.c_str() << std::endl;
                // Remove the temporary file because moving it over the target file
                // failed.
                remove(tmp_file.c_str());
                return false;
-       } else {
-               return true;
        }
+
+       return true;
 }
 
 bool Rename(const std::string &from, const std::string &to)