Function safe_join 

pub fn safe_join(base: &Path, path: &str) -> Result<PathBuf>

Safely joins a base path with a relative path, preventing directory traversal.

This function securely combines a base directory with a relative path while preventing directory traversal attacks. It validates the input path and ensures the result stays within the base directory.

Arguments

• base - The base directory that should contain the result
• path - The relative path to join (validated for safety)

Returns

The joined path with proper platform-specific handling, or an error if:

• The path contains invalid characters
• The path would escape the base directory
• Platform-specific validation fails

Examples

use agpm_cli::utils::platform::safe_join;
use std::path::Path;

let base = Path::new("/home/user/project");

// Safe joins
let file_path = safe_join(base, "src/main.rs")?;
let nested_path = safe_join(base, "docs/guide/intro.md")?;

// These would fail (directory traversal)
// safe_join(base, "../../../etc/passwd").unwrap_err();
// safe_join(base, "/absolute/path").unwrap_err();

Security Features

• Path traversal prevention: Detects and blocks ../ escape attempts
• Character validation: Ensures valid characters for the platform
• Normalization: Resolves . and .. components before validation
• Platform handling: Applies Windows long path support when needed

Validation Performed

1. Character validation: Checks for platform-invalid characters
2. Traversal detection: Identifies attempts to escape base directory
3. Path normalization: Resolves relative components
4. Boundary checking: Ensures result stays within base

Error Cases

• Path contains invalid characters (platform-specific)
• Path traversal attempt detected (../../../etc/passwd)
• Path would resolve outside the base directory
• Windows reserved names used in path components

Use Cases

• Processing user-provided relative paths
• Extracting archive files safely
• Configuration file path resolution
• API endpoints that accept file paths

Platform Behavior

• Windows: Handles long paths, validates reserved names
• Unix-like: Allows most characters, prevents null bytes
• All platforms: Prevents directory traversal attacks

See Also

• validate_path_chars for character validation details
• windows_long_path for Windows path handling
• is_safe_path for path safety checking