Mirrors/overte
3
0
Fork 0
mirror of https://github.com/overte-org/overte.git synced 2025-04-21 06:44:06 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

Fix possible corruption of ktx cache files

Browse source 
When creating a file like this:

  1. Create file
  2. Write file
  3. Close file

there is an opening before the file is written and closed where, if the
application were to crash (or not finish for any other reason), the file
would be left in an undefined state. Instead, this change updates it to
do this:

  1. Create temp file
  2. Write temp file
  3. Close temp file
  4. Move temp file to final path

This ensures that at step 3 we have a valid file, before we rename it.
We should never end up with a final file in an undefined state, but it is
possible to end up with a temp file that is an undefined state if we,
for instance, crash during step 2.
This commit is contained in:
Ryan Huffman 2017-05-09 12:02:12 -07:00
parent e92e710cdc
commit d86071d783
1 changed files with 9 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
libraries/networking/src/FileCache.cpp
View file

@ -110,10 +110,16 @@ FilePointer FileCache::writeFile(const char* data, File::Metadata&& metadata) {
return file;
}
// write the new file
FILE* saveFile = fopen(filepath.c_str(), "wb");
// write the data to a temporary file
std::string tmpFilepath = filepath + "_tmp";
FILE* saveFile = fopen(tmpFilepath.c_str(), "wb");
if (saveFile != nullptr && fwrite(data, metadata.length, 1, saveFile) && fclose(saveFile) == 0) {
file = addFile(std::move(metadata), filepath);
int result = rename(tmpFilepath.c_str(), filepath.c_str());
if (result == 0) {
file = addFile(std::move(metadata), filepath);
} else {
qCWarning(file_cache, "[%s] Failed to rename %s to %s (%s)", tmpFilepath.c_str(), filepath.c_str(), strerror(errno));
}
} else {
qCWarning(file_cache, "[%s] Failed to write %s (%s)", _dirname.c_str(), metadata.key.c_str(), strerror(errno));
errno = 0;