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1 //! A library to generate __fuzzed__ C headers for use with `quickcheck`
2 //!
3 //! ## Example
4 //!
5 //! ```rust
6 //! use quickcheck::{Arbitrary, Gen};
7 //! use quickchecking::fuzzers;
8 //!
9 //! fn main() {
10 //!     let generate_range: usize = 10; // Determines things like the length of
11 //!                                     // arbitrary vectors generated.
12 //!     let header = fuzzers::HeaderC::arbitrary(
13 //!        &mut Gen::new(generate_range));
14 //!     println!("{}", header);
15 //! }
16 //! ```
17 #![deny(missing_docs)]
18 
19 use quickcheck::{Gen, QuickCheck, TestResult};
20 use std::error::Error;
21 use std::fs::File;
22 use std::io::Write;
23 use std::path::{Path, PathBuf};
24 use std::process::{Command, Output};
25 use std::sync::Mutex;
26 use tempfile::Builder;
27 
28 /// Contains definitions of and impls for types used to fuzz C declarations.
29 pub mod fuzzers;
30 
31 // Global singleton, manages context across tests. For now that context is
32 // only the output_path for inspecting fuzzed headers (if specified).
33 struct Context {
34     output_path: Option<String>,
35 }
36 
37 // Initialize global context.
38 static CONTEXT: Mutex<Context> = Mutex::new(Context { output_path: None });
39 
40 // Passes fuzzed header to the `csmith-fuzzing/predicate.py` script, returns
41 // output of the associated command.
run_predicate_script( header: fuzzers::HeaderC, ) -> Result<Output, Box<dyn Error>>42 fn run_predicate_script(
43     header: fuzzers::HeaderC,
44 ) -> Result<Output, Box<dyn Error>> {
45     let dir = Builder::new().prefix("bindgen_prop").tempdir()?;
46     let header_path = dir.path().join("prop_test.h");
47 
48     let mut header_file = File::create(&header_path)?;
49     header_file.write_all(header.to_string().as_bytes())?;
50     header_file.sync_all()?;
51 
52     let header_path_string = header_path
53         .into_os_string()
54         .into_string()
55         .map_err(|_| "error converting path into String")?;
56 
57     let mut predicate_script_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
58     predicate_script_path.push("../../csmith-fuzzing/predicate.py");
59 
60     let predicate_script_path_string = predicate_script_path
61         .into_os_string()
62         .into_string()
63         .map_err(|_| "error converting path into String")?;
64 
65     // Copy generated temp files to output_path directory for inspection.
66     // If `None`, output path not specified, don't copy.
67     if let Some(ref path) = CONTEXT.lock().unwrap().output_path {
68         Command::new("cp")
69             .arg("-a")
70             .arg(dir.path().to_str().unwrap())
71             .arg(path)
72             .output()?;
73     }
74 
75     Ok(Command::new(predicate_script_path_string)
76         .arg(&header_path_string)
77         .output()?)
78 }
79 
80 // Generatable property. Pass generated headers off to run through the
81 // `csmith-fuzzing/predicate.py` script. Success is measured by the success
82 // status of that command.
bindgen_prop(header: fuzzers::HeaderC) -> TestResult83 fn bindgen_prop(header: fuzzers::HeaderC) -> TestResult {
84     match run_predicate_script(header) {
85         Ok(o) => TestResult::from_bool(o.status.success()),
86         Err(e) => {
87             println!("{:?}", e);
88             TestResult::from_bool(false)
89         }
90     }
91 }
92 
93 /// Instantiate a Quickcheck object and use it to run property tests using
94 /// fuzzed C headers generated with types defined in the `fuzzers` module.
95 /// Success/Failure is dictated by the result of passing the fuzzed headers
96 /// to the `csmith-fuzzing/predicate.py` script.
test_bindgen( generate_range: usize, tests: u64, output_path: Option<&Path>, )97 pub fn test_bindgen(
98     generate_range: usize,
99     tests: u64,
100     output_path: Option<&Path>,
101 ) {
102     if let Some(path) = output_path {
103         CONTEXT.lock().unwrap().output_path = Some(path.display().to_string());
104     }
105 
106     QuickCheck::new()
107         .tests(tests)
108         .gen(Gen::new(generate_range))
109         .quickcheck(bindgen_prop as fn(fuzzers::HeaderC) -> TestResult)
110 }
111