Function writeFileContent

src/filesystem/lib.ts:161–185

(filePath: string, content: string)

}

export async function writeFileContent(filePath: string, content: string): Promise<void> {
  try {
    // Security: 'wx' flag ensures exclusive creation - fails if file/symlink exists,
    // preventing writes through pre-existing symlinks
    await fs.writeFile(filePath, content, { encoding: "utf-8", flag: 'wx' });
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code === 'EEXIST') {
      // Security: Use atomic rename to prevent race conditions where symlinks
      // could be created between validation and write. Rename operations
      // replace the target file atomically and don't follow symlinks.
      const tempPath = `${filePath}.${randomBytes(16).toString('hex')}.tmp`;
      try {
        await fs.writeFile(tempPath, content, 'utf-8');
        await fs.rename(tempPath, filePath);
      } catch (renameError) {
        try {
          await fs.unlink(tempPath);
        } catch {}
        throw renameError;
      }
    } else {
      throw error;
    }
  }
}


// File Editing Functions