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| 1 | +// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT |
| 2 | +// file at the top-level directory of this distribution and at |
| 3 | +// http://rust-lang.org/COPYRIGHT. |
| 4 | +// |
| 5 | +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 7 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| 8 | +// option. This file may not be copied, modified, or distributed |
| 9 | +// except according to those terms. |
| 10 | + |
| 11 | +use io; |
| 12 | +use io::prelude::*; |
| 13 | +use libc; |
| 14 | + |
| 15 | +use sys::backtrace::{output, output_fileline}; |
| 16 | +pub fn print(w: &mut Write, idx: isize, addr: *mut libc::c_void, |
| 17 | + symaddr: *mut libc::c_void) -> io::Result<()> { |
| 18 | + use env; |
| 19 | + use ffi::CStr; |
| 20 | + use os::unix::prelude::*; |
| 21 | + use ptr; |
| 22 | + |
| 23 | + //////////////////////////////////////////////////////////////////////// |
| 24 | + // libbacktrace.h API |
| 25 | + //////////////////////////////////////////////////////////////////////// |
| 26 | + type backtrace_syminfo_callback = |
| 27 | + extern "C" fn(data: *mut libc::c_void, |
| 28 | + pc: libc::uintptr_t, |
| 29 | + symname: *const libc::c_char, |
| 30 | + symval: libc::uintptr_t, |
| 31 | + symsize: libc::uintptr_t); |
| 32 | + type backtrace_full_callback = |
| 33 | + extern "C" fn(data: *mut libc::c_void, |
| 34 | + pc: libc::uintptr_t, |
| 35 | + filename: *const libc::c_char, |
| 36 | + lineno: libc::c_int, |
| 37 | + function: *const libc::c_char) -> libc::c_int; |
| 38 | + type backtrace_error_callback = |
| 39 | + extern "C" fn(data: *mut libc::c_void, |
| 40 | + msg: *const libc::c_char, |
| 41 | + errnum: libc::c_int); |
| 42 | + enum backtrace_state {} |
| 43 | + #[link(name = "backtrace", kind = "static")] |
| 44 | + #[cfg(not(test))] |
| 45 | + extern {} |
| 46 | + |
| 47 | + extern { |
| 48 | + fn backtrace_create_state(filename: *const libc::c_char, |
| 49 | + threaded: libc::c_int, |
| 50 | + error: backtrace_error_callback, |
| 51 | + data: *mut libc::c_void) |
| 52 | + -> *mut backtrace_state; |
| 53 | + fn backtrace_syminfo(state: *mut backtrace_state, |
| 54 | + addr: libc::uintptr_t, |
| 55 | + cb: backtrace_syminfo_callback, |
| 56 | + error: backtrace_error_callback, |
| 57 | + data: *mut libc::c_void) -> libc::c_int; |
| 58 | + fn backtrace_pcinfo(state: *mut backtrace_state, |
| 59 | + addr: libc::uintptr_t, |
| 60 | + cb: backtrace_full_callback, |
| 61 | + error: backtrace_error_callback, |
| 62 | + data: *mut libc::c_void) -> libc::c_int; |
| 63 | + } |
| 64 | + |
| 65 | + //////////////////////////////////////////////////////////////////////// |
| 66 | + // helper callbacks |
| 67 | + //////////////////////////////////////////////////////////////////////// |
| 68 | + |
| 69 | + type FileLine = (*const libc::c_char, libc::c_int); |
| 70 | + |
| 71 | + extern fn error_cb(_data: *mut libc::c_void, _msg: *const libc::c_char, |
| 72 | + _errnum: libc::c_int) { |
| 73 | + // do nothing for now |
| 74 | + } |
| 75 | + extern fn syminfo_cb(data: *mut libc::c_void, |
| 76 | + _pc: libc::uintptr_t, |
| 77 | + symname: *const libc::c_char, |
| 78 | + _symval: libc::uintptr_t, |
| 79 | + _symsize: libc::uintptr_t) { |
| 80 | + let slot = data as *mut *const libc::c_char; |
| 81 | + unsafe { *slot = symname; } |
| 82 | + } |
| 83 | + extern fn pcinfo_cb(data: *mut libc::c_void, |
| 84 | + _pc: libc::uintptr_t, |
| 85 | + filename: *const libc::c_char, |
| 86 | + lineno: libc::c_int, |
| 87 | + _function: *const libc::c_char) -> libc::c_int { |
| 88 | + if !filename.is_null() { |
| 89 | + let slot = data as *mut &mut [FileLine]; |
| 90 | + let buffer = unsafe {ptr::read(slot)}; |
| 91 | + |
| 92 | + // if the buffer is not full, add file:line to the buffer |
| 93 | + // and adjust the buffer for next possible calls to pcinfo_cb. |
| 94 | + if !buffer.is_empty() { |
| 95 | + buffer[0] = (filename, lineno); |
| 96 | + unsafe { ptr::write(slot, &mut buffer[1..]); } |
| 97 | + } |
| 98 | + } |
| 99 | + |
| 100 | + 0 |
| 101 | + } |
| 102 | + |
| 103 | + // The libbacktrace API supports creating a state, but it does not |
| 104 | + // support destroying a state. I personally take this to mean that a |
| 105 | + // state is meant to be created and then live forever. |
| 106 | + // |
| 107 | + // I would love to register an at_exit() handler which cleans up this |
| 108 | + // state, but libbacktrace provides no way to do so. |
| 109 | + // |
| 110 | + // With these constraints, this function has a statically cached state |
| 111 | + // that is calculated the first time this is requested. Remember that |
| 112 | + // backtracing all happens serially (one global lock). |
| 113 | + // |
| 114 | + // An additionally oddity in this function is that we initialize the |
| 115 | + // filename via self_exe_name() to pass to libbacktrace. It turns out |
| 116 | + // that on Linux libbacktrace seamlessly gets the filename of the |
| 117 | + // current executable, but this fails on freebsd. by always providing |
| 118 | + // it, we make sure that libbacktrace never has a reason to not look up |
| 119 | + // the symbols. The libbacktrace API also states that the filename must |
| 120 | + // be in "permanent memory", so we copy it to a static and then use the |
| 121 | + // static as the pointer. |
| 122 | + // |
| 123 | + // FIXME: We also call self_exe_name() on DragonFly BSD. I haven't |
| 124 | + // tested if this is required or not. |
| 125 | + unsafe fn init_state() -> *mut backtrace_state { |
| 126 | + static mut STATE: *mut backtrace_state = 0 as *mut backtrace_state; |
| 127 | + static mut LAST_FILENAME: [libc::c_char; 256] = [0; 256]; |
| 128 | + if !STATE.is_null() { return STATE } |
| 129 | + let selfname = if cfg!(target_os = "freebsd") || |
| 130 | + cfg!(target_os = "dragonfly") || |
| 131 | + cfg!(target_os = "bitrig") || |
| 132 | + cfg!(target_os = "openbsd") { |
| 133 | + env::current_exe().ok() |
| 134 | + } else { |
| 135 | + None |
| 136 | + }; |
| 137 | + let filename = match selfname { |
| 138 | + Some(path) => { |
| 139 | + let bytes = path.as_os_str().as_bytes(); |
| 140 | + if bytes.len() < LAST_FILENAME.len() { |
| 141 | + let i = bytes.iter(); |
| 142 | + for (slot, val) in LAST_FILENAME.iter_mut().zip(i) { |
| 143 | + *slot = *val as libc::c_char; |
| 144 | + } |
| 145 | + LAST_FILENAME.as_ptr() |
| 146 | + } else { |
| 147 | + ptr::null() |
| 148 | + } |
| 149 | + } |
| 150 | + None => ptr::null(), |
| 151 | + }; |
| 152 | + STATE = backtrace_create_state(filename, 0, error_cb, |
| 153 | + ptr::null_mut()); |
| 154 | + return STATE |
| 155 | + } |
| 156 | + |
| 157 | + //////////////////////////////////////////////////////////////////////// |
| 158 | + // translation |
| 159 | + //////////////////////////////////////////////////////////////////////// |
| 160 | + |
| 161 | + // backtrace errors are currently swept under the rug, only I/O |
| 162 | + // errors are reported |
| 163 | + let state = unsafe { init_state() }; |
| 164 | + if state.is_null() { |
| 165 | + return output(w, idx, addr, None) |
| 166 | + } |
| 167 | + let mut data = ptr::null(); |
| 168 | + let data_addr = &mut data as *mut *const libc::c_char; |
| 169 | + let ret = unsafe { |
| 170 | + backtrace_syminfo(state, symaddr as libc::uintptr_t, |
| 171 | + syminfo_cb, error_cb, |
| 172 | + data_addr as *mut libc::c_void) |
| 173 | + }; |
| 174 | + if ret == 0 || data.is_null() { |
| 175 | + try!(output(w, idx, addr, None)); |
| 176 | + } else { |
| 177 | + try!(output(w, idx, addr, Some(unsafe { CStr::from_ptr(data).to_bytes() }))); |
| 178 | + } |
| 179 | + |
| 180 | + // pcinfo may return an arbitrary number of file:line pairs, |
| 181 | + // in the order of stack trace (i.e. inlined calls first). |
| 182 | + // in order to avoid allocation, we stack-allocate a fixed size of entries. |
| 183 | + const FILELINE_SIZE: usize = 32; |
| 184 | + let mut fileline_buf = [(ptr::null(), -1); FILELINE_SIZE]; |
| 185 | + let ret; |
| 186 | + let fileline_count; |
| 187 | + { |
| 188 | + let mut fileline_win: &mut [FileLine] = &mut fileline_buf; |
| 189 | + let fileline_addr = &mut fileline_win as *mut &mut [FileLine]; |
| 190 | + ret = unsafe { |
| 191 | + backtrace_pcinfo(state, addr as libc::uintptr_t, |
| 192 | + pcinfo_cb, error_cb, |
| 193 | + fileline_addr as *mut libc::c_void) |
| 194 | + }; |
| 195 | + fileline_count = FILELINE_SIZE - fileline_win.len(); |
| 196 | + } |
| 197 | + if ret == 0 { |
| 198 | + for (i, &(file, line)) in fileline_buf[..fileline_count].iter().enumerate() { |
| 199 | + if file.is_null() { continue; } // just to be sure |
| 200 | + let file = unsafe { CStr::from_ptr(file).to_bytes() }; |
| 201 | + try!(output_fileline(w, file, line, i == FILELINE_SIZE - 1)); |
| 202 | + } |
| 203 | + } |
| 204 | + |
| 205 | + Ok(()) |
| 206 | +} |
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