1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
//! A library for acquiring a backtrace at runtime
//!
//! This library is meant to supplement the `RUST_BACKTRACE=1` support of the
//! standard library by allowing an acquisition of a backtrace at runtime
//! programmatically. The backtraces generated by this library do not need to be
//! parsed, for example, and expose the functionality of multiple backend
//! implementations.
//!
//! # Implementation
//!
//! This library makes use of a number of strategies for actually acquiring a
//! backtrace. For example unix uses libgcc's libunwind bindings by default to
//! acquire a backtrace, but coresymbolication or dladdr is used on OSX to
//! acquire symbol names while linux uses gcc's libbacktrace.
//!
//! When using the default feature set of this library the "most reasonable" set
//! of defaults is chosen for the current platform, but the features activated
//! can also be controlled at a finer granularity.
//!
//! # Platform Support
//!
//! Currently this library is verified to work on Linux, OSX, and Windows, but
//! it may work on other platforms as well. Note that the quality of the
//! backtrace may vary across platforms.
//!
//! # API Principles
//!
//! This library attempts to be as flexible as possible to accommodate different
//! backend implementations of acquiring a backtrace. Consequently the currently
//! exported functions are closure-based as opposed to the likely expected
//! iterator-based versions. This is done due to limitations of the underlying
//! APIs used from the system.
//!
//! # Usage
//!
//! First, add this to your Cargo.toml
//!
//! ```toml
//! [dependencies]
//! backtrace = "0.2"
//! ```
//!
//! Next:
//!
//! ```
//! extern crate backtrace;
//!
//! fn main() {
//!     backtrace::trace(|frame| {
//!         let ip = frame.ip();
//!         let symbol_address = frame.symbol_address();
//!
//!         // Resolve this instruction pointer to a symbol name
//!         backtrace::resolve(ip, |symbol| {
//!             if let Some(name) = symbol.name() {
//!                 // ...
//!             }
//!             if let Some(filename) = symbol.filename() {
//!                 // ...
//!             }
//!         });
//!
//!         true // keep going to the next frame
//!     });
//! }
//! ```

#![doc(html_root_url = "https://docs.rs/backtrace")]
#![deny(missing_docs)]
#![deny(warnings)]

#[cfg(unix)]
extern crate libc;
#[cfg(all(windows, feature = "winapi"))] extern crate winapi;

#[cfg(feature = "serde_derive")]
#[cfg_attr(feature = "serde_derive", macro_use)]
extern crate serde_derive;

#[cfg(feature = "rustc-serialize")]
extern crate rustc_serialize;

#[macro_use]
extern crate cfg_if;

extern crate rustc_demangle;

#[cfg(feature = "cpp_demangle")]
extern crate cpp_demangle;

cfg_if! {
    if #[cfg(all(feature = "gimli-symbolize", unix, target_os = "linux"))] {
        extern crate addr2line;
        extern crate findshlibs;
        extern crate gimli;
        extern crate memmap;
        extern crate object;
    }
}

#[allow(dead_code)] // not used everywhere
#[cfg(unix)]
#[macro_use]
mod dylib;

pub use backtrace::{trace, Frame};
mod backtrace;

pub use symbolize::{resolve, Symbol, SymbolName};
mod symbolize;

pub use capture::{Backtrace, BacktraceFrame, BacktraceSymbol};
mod capture;

#[allow(dead_code)]
struct Bomb {
    enabled: bool,
}

#[allow(dead_code)]
impl Drop for Bomb {
    fn drop(&mut self) {
        if self.enabled {
            panic!("cannot panic during the backtrace function");
        }
    }
}

#[allow(dead_code)]
mod lock {
    use std::cell::Cell;
    use std::mem;
    use std::sync::{Once, Mutex, MutexGuard, ONCE_INIT};

    pub struct LockGuard(MutexGuard<'static, ()>);

    static mut LOCK: *mut Mutex<()> = 0 as *mut _;
    static INIT: Once = ONCE_INIT;
    thread_local!(static LOCK_HELD: Cell<bool> = Cell::new(false));

    impl Drop for LockGuard {
        fn drop(&mut self) {
            LOCK_HELD.with(|slot| {
                assert!(slot.get());
                slot.set(false);
            });
        }
    }

    pub fn lock() -> Option<LockGuard> {
        if LOCK_HELD.with(|l| l.get()) {
            return None
        }
        LOCK_HELD.with(|s| s.set(true));
        unsafe {
            INIT.call_once(|| {
                LOCK = mem::transmute(Box::new(Mutex::new(())));
            });
            Some(LockGuard((*LOCK).lock().unwrap()))
        }
    }
}

// requires external synchronization
#[cfg(all(windows, feature = "dbghelp"))]
unsafe fn dbghelp_init() {
    use winapi::shared::minwindef;
    use winapi::um::{dbghelp, processthreadsapi};

    static mut INITIALIZED: bool = false;

    if !INITIALIZED {
        dbghelp::SymInitializeW(processthreadsapi::GetCurrentProcess(),
                                0 as *mut _,
                                minwindef::TRUE);
        INITIALIZED = true;
    }
}