| // 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 libc; |
| |
| use ffi::CStr; |
| use io; |
| use mem; |
| use ptr; |
| use sys::backtrace::BacktraceContext; |
| use sys_common::backtrace::Frame; |
| |
| pub fn foreach_symbol_fileline<F>(frame: Frame, |
| mut f: F, |
| _: &BacktraceContext) -> io::Result<bool> |
| where F: FnMut(&[u8], u32) -> io::Result<()> |
| { |
| // 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(), !0); FILELINE_SIZE]; |
| let ret; |
| let fileline_count = { |
| let state = unsafe { init_state() }; |
| if state.is_null() { |
| return Err(io::Error::new( |
| io::ErrorKind::Other, |
| "failed to allocate libbacktrace state") |
| ) |
| } |
| let mut fileline_win: &mut [FileLine] = &mut fileline_buf; |
| let fileline_addr = &mut fileline_win as *mut &mut [FileLine]; |
| ret = unsafe { |
| backtrace_pcinfo(state, |
| frame.exact_position as libc::uintptr_t, |
| pcinfo_cb, |
| error_cb, |
| fileline_addr as *mut libc::c_void) |
| }; |
| FILELINE_SIZE - fileline_win.len() |
| }; |
| if ret == 0 { |
| for &(file, line) in &fileline_buf[..fileline_count] { |
| if file.is_null() { continue; } // just to be sure |
| let file = unsafe { CStr::from_ptr(file).to_bytes() }; |
| f(file, line)?; |
| } |
| Ok(fileline_count == FILELINE_SIZE) |
| } else { |
| Ok(false) |
| } |
| } |
| |
| /// Converts a pointer to symbol to its string value. |
| pub fn resolve_symname<F>(frame: Frame, |
| callback: F, |
| _: &BacktraceContext) -> io::Result<()> |
| where F: FnOnce(Option<&str>) -> io::Result<()> |
| { |
| let symname = { |
| let state = unsafe { init_state() }; |
| if state.is_null() { |
| return Err(io::Error::new( |
| io::ErrorKind::Other, |
| "failed to allocate libbacktrace state") |
| ) |
| } |
| let mut data: *const libc::c_char = ptr::null(); |
| let data_addr = &mut data as *mut *const libc::c_char; |
| let ret = unsafe { |
| backtrace_syminfo(state, |
| frame.symbol_addr as libc::uintptr_t, |
| syminfo_cb, |
| error_cb, |
| data_addr as *mut libc::c_void) |
| }; |
| if ret == 0 || data.is_null() { |
| None |
| } else { |
| unsafe { |
| CStr::from_ptr(data).to_str().ok() |
| } |
| } |
| }; |
| callback(symname) |
| } |
| |
| //////////////////////////////////////////////////////////////////////// |
| // 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 {} |
| |
| 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, u32); |
| |
| 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 as u32); |
| 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). |
| // |
| // Things don't work so well on not-Linux since libbacktrace can't track |
| // down that executable this is. We at one point used env::current_exe but |
| // it turns out that there are some serious security issues with that |
| // approach. |
| // |
| // Specifically, on certain platforms like BSDs, a malicious actor can cause |
| // an arbitrary file to be placed at the path returned by current_exe. |
| // libbacktrace does not behave defensively in the presence of ill-formed |
| // DWARF information, and has been demonstrated to segfault in at least one |
| // case. There is no evidence at the moment to suggest that a more carefully |
| // constructed file can't cause arbitrary code execution. As a result of all |
| // of this, we don't hint libbacktrace with the path to the current process. |
| unsafe fn init_state() -> *mut backtrace_state { |
| static mut STATE: *mut backtrace_state = ptr::null_mut(); |
| if !STATE.is_null() { return STATE } |
| |
| let filename = match ::sys::backtrace::gnu::get_executable_filename() { |
| Ok((filename, file)) => { |
| // filename is purposely leaked here since libbacktrace requires |
| // it to stay allocated permanently, file is also leaked so that |
| // the file stays locked |
| let filename_ptr = filename.as_ptr(); |
| mem::forget(filename); |
| mem::forget(file); |
| filename_ptr |
| }, |
| Err(_) => ptr::null(), |
| }; |
| |
| STATE = backtrace_create_state(filename, 0, error_cb, |
| ptr::null_mut()); |
| STATE |
| } |
