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load_magic_file

libmagic_rs::parser

Function load_magic_file 

Source 
pub fn load_magic_file(path: &Path) -> Result<Vec<MagicRule>, ParseError>
Expand description

Loads magic rules from a file or directory, automatically detecting the format.

This is the unified entry point for loading magic rules from the filesystem. It automatically detects whether the path points to a text magic file, a directory containing magic files, or a binary compiled magic file, and dispatches to the appropriate handler.

§Format Detection and Handling

The function uses detect_format() to determine the file type and handles each format as follows:

§Arguments

  • path - Path to a magic file or directory. Can be absolute or relative.

§Returns

Returns Ok(Vec<MagicRule>) containing all successfully parsed magic rules. For directories, rules from all files are merged in alphabetical order by filename.

§Errors

This function returns a ParseError in the following cases:

  • File not found: The specified path does not exist
  • Unsupported format: The file is a binary compiled magic file (.mgc)
  • Parse errors: The magic file contains syntax errors or invalid rules
  • I/O errors: File system errors during reading (permissions, disk errors, etc.)

§Examples

§Loading a text magic file

use libmagic_rs::parser::load_magic_file;
use std::path::Path;

let rules = load_magic_file(Path::new("/usr/share/misc/magic"))?;
println!("Loaded {} magic rules", rules.len());

§Loading a directory of magic files

use libmagic_rs::parser::load_magic_file;
use std::path::Path;

let rules = load_magic_file(Path::new("/usr/share/misc/magic.d"))?;
println!("Loaded {} rules from directory", rules.len());

§Handling binary format errors

use libmagic_rs::parser::load_magic_file;
use std::path::Path;

match load_magic_file(Path::new("/usr/share/misc/magic.mgc")) {
    Ok(rules) => println!("Loaded {} rules", rules.len()),
    Err(e) => {
        eprintln!("Error loading magic file: {}", e);
        eprintln!("Hint: Use --use-builtin for binary files");
    }
}

§Security

This function delegates to super::parse_text_magic_file() or load_magic_directory() based on format detection. Security considerations are handled by those functions:

  • Rule hierarchy depth is bounded during parsing
  • Invalid syntax is rejected with descriptive errors
  • Binary .mgc files are rejected (not parsed)

Note: File size limits and memory exhaustion protection are not currently implemented. Large magic files will be loaded entirely into memory.

§See Also