| // Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| use io; |
| use io::prelude::*; |
| use libc; |
| use sys_common::backtrace::{output, output_fileline}; |
| |
| pub fn print(w: &mut Write, idx: isize, addr: *mut libc::c_void, |
| symaddr: *mut libc::c_void) -> io::Result<()> { |
| use env; |
| use ffi::CStr; |
| use ptr; |
| |
| //////////////////////////////////////////////////////////////////////// |
| // libbacktrace.h API |
| //////////////////////////////////////////////////////////////////////// |
| type backtrace_syminfo_callback = |
| extern "C" fn(data: *mut libc::c_void, |
| pc: libc::uintptr_t, |
| symname: *const libc::c_char, |
| symval: libc::uintptr_t, |
| symsize: libc::uintptr_t); |
| type backtrace_full_callback = |
| extern "C" fn(data: *mut libc::c_void, |
| pc: libc::uintptr_t, |
| filename: *const libc::c_char, |
| lineno: libc::c_int, |
| function: *const libc::c_char) -> libc::c_int; |
| type backtrace_error_callback = |
| extern "C" fn(data: *mut libc::c_void, |
| msg: *const libc::c_char, |
| errnum: libc::c_int); |
| enum backtrace_state {} |
| #[link(name = "backtrace", kind = "static")] |
| #[cfg(not(test))] |
| extern {} |
| |
| extern { |
| fn backtrace_create_state(filename: *const libc::c_char, |
| threaded: libc::c_int, |
| error: backtrace_error_callback, |
| data: *mut libc::c_void) |
| -> *mut backtrace_state; |
| fn backtrace_syminfo(state: *mut backtrace_state, |
| addr: libc::uintptr_t, |
| cb: backtrace_syminfo_callback, |
| error: backtrace_error_callback, |
| data: *mut libc::c_void) -> libc::c_int; |
| fn backtrace_pcinfo(state: *mut backtrace_state, |
| addr: libc::uintptr_t, |
| cb: backtrace_full_callback, |
| error: backtrace_error_callback, |
| data: *mut libc::c_void) -> libc::c_int; |
| } |
| |
| //////////////////////////////////////////////////////////////////////// |
| // helper callbacks |
| //////////////////////////////////////////////////////////////////////// |
| |
| type FileLine = (*const libc::c_char, libc::c_int); |
| |
| extern fn error_cb(_data: *mut libc::c_void, _msg: *const libc::c_char, |
| _errnum: libc::c_int) { |
| // do nothing for now |
| } |
| extern fn syminfo_cb(data: *mut libc::c_void, |
| _pc: libc::uintptr_t, |
| symname: *const libc::c_char, |
| _symval: libc::uintptr_t, |
| _symsize: libc::uintptr_t) { |
| let slot = data as *mut *const libc::c_char; |
| unsafe { *slot = symname; } |
| } |
| extern fn pcinfo_cb(data: *mut libc::c_void, |
| _pc: libc::uintptr_t, |
| filename: *const libc::c_char, |
| lineno: libc::c_int, |
| _function: *const libc::c_char) -> libc::c_int { |
| if !filename.is_null() { |
| let slot = data as *mut &mut [FileLine]; |
| let buffer = unsafe {ptr::read(slot)}; |
| |
| // if the buffer is not full, add file:line to the buffer |
| // and adjust the buffer for next possible calls to pcinfo_cb. |
| if !buffer.is_empty() { |
| buffer[0] = (filename, lineno); |
| unsafe { ptr::write(slot, &mut buffer[1..]); } |
| } |
| } |
| |
| 0 |
| } |
| |
| // The libbacktrace API supports creating a state, but it does not |
| // support destroying a state. I personally take this to mean that a |
| // state is meant to be created and then live forever. |
| // |
| // I would love to register an at_exit() handler which cleans up this |
| // state, but libbacktrace provides no way to do so. |
| // |
| // With these constraints, this function has a statically cached state |
| // that is calculated the first time this is requested. Remember that |
| // backtracing all happens serially (one global lock). |
| // |
| // An additionally oddity in this function is that we initialize the |
| // filename via self_exe_name() to pass to libbacktrace. It turns out |
| // that on Linux libbacktrace seamlessly gets the filename of the |
| // current executable, but this fails on freebsd. by always providing |
| // it, we make sure that libbacktrace never has a reason to not look up |
| // the symbols. The libbacktrace API also states that the filename must |
| // be in "permanent memory", so we copy it to a static and then use the |
| // static as the pointer. |
| // |
| // FIXME: We also call self_exe_name() on DragonFly BSD. I haven't |
| // tested if this is required or not. |
| unsafe fn init_state() -> *mut backtrace_state { |
| static mut STATE: *mut backtrace_state = ptr::null_mut(); |
| static mut LAST_FILENAME: [libc::c_char; 256] = [0; 256]; |
| if !STATE.is_null() { return STATE } |
| let selfname = if cfg!(target_os = "freebsd") || |
| cfg!(target_os = "dragonfly") || |
| cfg!(target_os = "bitrig") || |
| cfg!(target_os = "openbsd") || |
| cfg!(target_os = "windows") { |
| env::current_exe().ok() |
| } else { |
| None |
| }; |
| let filename = match selfname.as_ref().and_then(|s| s.to_str()) { |
| Some(path) => { |
| let bytes = path.as_bytes(); |
| if bytes.len() < LAST_FILENAME.len() { |
| let i = bytes.iter(); |
| for (slot, val) in LAST_FILENAME.iter_mut().zip(i) { |
| *slot = *val as libc::c_char; |
| } |
| LAST_FILENAME.as_ptr() |
| } else { |
| ptr::null() |
| } |
| } |
| None => ptr::null(), |
| }; |
| STATE = backtrace_create_state(filename, 0, error_cb, |
| ptr::null_mut()); |
| STATE |
| } |
| |
| //////////////////////////////////////////////////////////////////////// |
| // translation |
| //////////////////////////////////////////////////////////////////////// |
| |
| // backtrace errors are currently swept under the rug, only I/O |
| // errors are reported |
| let state = unsafe { init_state() }; |
| if state.is_null() { |
| return output(w, idx, addr, None) |
| } |
| let mut data = ptr::null(); |
| let data_addr = &mut data as *mut *const libc::c_char; |
| let ret = unsafe { |
| backtrace_syminfo(state, symaddr as libc::uintptr_t, |
| syminfo_cb, error_cb, |
| data_addr as *mut libc::c_void) |
| }; |
| if ret == 0 || data.is_null() { |
| try!(output(w, idx, addr, None)); |
| } else { |
| try!(output(w, idx, addr, Some(unsafe { CStr::from_ptr(data).to_bytes() }))); |
| } |
| |
| // pcinfo may return an arbitrary number of file:line pairs, |
| // in the order of stack trace (i.e. inlined calls first). |
| // in order to avoid allocation, we stack-allocate a fixed size of entries. |
| const FILELINE_SIZE: usize = 32; |
| let mut fileline_buf = [(ptr::null(), -1); FILELINE_SIZE]; |
| let ret; |
| let fileline_count; |
| { |
| let mut fileline_win: &mut [FileLine] = &mut fileline_buf; |
| let fileline_addr = &mut fileline_win as *mut &mut [FileLine]; |
| ret = unsafe { |
| backtrace_pcinfo(state, addr as libc::uintptr_t, |
| pcinfo_cb, error_cb, |
| fileline_addr as *mut libc::c_void) |
| }; |
| fileline_count = FILELINE_SIZE - fileline_win.len(); |
| } |
| if ret == 0 { |
| for (i, &(file, line)) in fileline_buf[..fileline_count].iter().enumerate() { |
| if file.is_null() { continue; } // just to be sure |
| let file = unsafe { CStr::from_ptr(file).to_bytes() }; |
| try!(output_fileline(w, file, line, i == FILELINE_SIZE - 1)); |
| } |
| } |
| |
| Ok(()) |
| } |
