From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- library/backtrace/src/print.rs | 302 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 302 insertions(+) create mode 100644 library/backtrace/src/print.rs (limited to 'library/backtrace/src/print.rs') diff --git a/library/backtrace/src/print.rs b/library/backtrace/src/print.rs new file mode 100644 index 000000000..cc677122a --- /dev/null +++ b/library/backtrace/src/print.rs @@ -0,0 +1,302 @@ +#[cfg(feature = "std")] +use super::{BacktraceFrame, BacktraceSymbol}; +use super::{BytesOrWideString, Frame, SymbolName}; +use core::ffi::c_void; +use core::fmt; + +const HEX_WIDTH: usize = 2 + 2 * core::mem::size_of::(); + +#[cfg(target_os = "fuchsia")] +mod fuchsia; + +/// A formatter for backtraces. +/// +/// This type can be used to print a backtrace regardless of where the backtrace +/// itself comes from. If you have a `Backtrace` type then its `Debug` +/// implementation already uses this printing format. +pub struct BacktraceFmt<'a, 'b> { + fmt: &'a mut fmt::Formatter<'b>, + frame_index: usize, + format: PrintFmt, + print_path: + &'a mut (dyn FnMut(&mut fmt::Formatter<'_>, BytesOrWideString<'_>) -> fmt::Result + 'b), +} + +/// The styles of printing that we can print +#[derive(Copy, Clone, Eq, PartialEq)] +pub enum PrintFmt { + /// Prints a terser backtrace which ideally only contains relevant information + Short, + /// Prints a backtrace that contains all possible information + Full, + #[doc(hidden)] + __Nonexhaustive, +} + +impl<'a, 'b> BacktraceFmt<'a, 'b> { + /// Create a new `BacktraceFmt` which will write output to the provided + /// `fmt`. + /// + /// The `format` argument will control the style in which the backtrace is + /// printed, and the `print_path` argument will be used to print the + /// `BytesOrWideString` instances of filenames. This type itself doesn't do + /// any printing of filenames, but this callback is required to do so. + pub fn new( + fmt: &'a mut fmt::Formatter<'b>, + format: PrintFmt, + print_path: &'a mut (dyn FnMut(&mut fmt::Formatter<'_>, BytesOrWideString<'_>) -> fmt::Result + + 'b), + ) -> Self { + BacktraceFmt { + fmt, + frame_index: 0, + format, + print_path, + } + } + + /// Prints a preamble for the backtrace about to be printed. + /// + /// This is required on some platforms for backtraces to be fully + /// symbolicated later, and otherwise this should just be the first method + /// you call after creating a `BacktraceFmt`. + pub fn add_context(&mut self) -> fmt::Result { + #[cfg(target_os = "fuchsia")] + fuchsia::print_dso_context(self.fmt)?; + Ok(()) + } + + /// Adds a frame to the backtrace output. + /// + /// This commit returns an RAII instance of a `BacktraceFrameFmt` which can be used + /// to actually print a frame, and on destruction it will increment the + /// frame counter. + pub fn frame(&mut self) -> BacktraceFrameFmt<'_, 'a, 'b> { + BacktraceFrameFmt { + fmt: self, + symbol_index: 0, + } + } + + /// Completes the backtrace output. + /// + /// This is currently a no-op but is added for future compatibility with + /// backtrace formats. + pub fn finish(&mut self) -> fmt::Result { + // Currently a no-op-- including this hook to allow for future additions. + Ok(()) + } +} + +/// A formatter for just one frame of a backtrace. +/// +/// This type is created by the `BacktraceFmt::frame` function. +pub struct BacktraceFrameFmt<'fmt, 'a, 'b> { + fmt: &'fmt mut BacktraceFmt<'a, 'b>, + symbol_index: usize, +} + +impl BacktraceFrameFmt<'_, '_, '_> { + /// Prints a `BacktraceFrame` with this frame formatter. + /// + /// This will recursively print all `BacktraceSymbol` instances within the + /// `BacktraceFrame`. + /// + /// # Required features + /// + /// This function requires the `std` feature of the `backtrace` crate to be + /// enabled, and the `std` feature is enabled by default. + #[cfg(feature = "std")] + pub fn backtrace_frame(&mut self, frame: &BacktraceFrame) -> fmt::Result { + let symbols = frame.symbols(); + for symbol in symbols { + self.backtrace_symbol(frame, symbol)?; + } + if symbols.is_empty() { + self.print_raw(frame.ip(), None, None, None)?; + } + Ok(()) + } + + /// Prints a `BacktraceSymbol` within a `BacktraceFrame`. + /// + /// # Required features + /// + /// This function requires the `std` feature of the `backtrace` crate to be + /// enabled, and the `std` feature is enabled by default. + #[cfg(feature = "std")] + pub fn backtrace_symbol( + &mut self, + frame: &BacktraceFrame, + symbol: &BacktraceSymbol, + ) -> fmt::Result { + self.print_raw_with_column( + frame.ip(), + symbol.name(), + // TODO: this isn't great that we don't end up printing anything + // with non-utf8 filenames. Thankfully almost everything is utf8 so + // this shouldn't be too too bad. + symbol + .filename() + .and_then(|p| Some(BytesOrWideString::Bytes(p.to_str()?.as_bytes()))), + symbol.lineno(), + symbol.colno(), + )?; + Ok(()) + } + + /// Prints a raw traced `Frame` and `Symbol`, typically from within the raw + /// callbacks of this crate. + pub fn symbol(&mut self, frame: &Frame, symbol: &super::Symbol) -> fmt::Result { + self.print_raw_with_column( + frame.ip(), + symbol.name(), + symbol.filename_raw(), + symbol.lineno(), + symbol.colno(), + )?; + Ok(()) + } + + /// Adds a raw frame to the backtrace output. + /// + /// This method, unlike the previous, takes the raw arguments in case + /// they're being source from different locations. Note that this may be + /// called multiple times for one frame. + pub fn print_raw( + &mut self, + frame_ip: *mut c_void, + symbol_name: Option>, + filename: Option>, + lineno: Option, + ) -> fmt::Result { + self.print_raw_with_column(frame_ip, symbol_name, filename, lineno, None) + } + + /// Adds a raw frame to the backtrace output, including column information. + /// + /// This method, like the previous, takes the raw arguments in case + /// they're being source from different locations. Note that this may be + /// called multiple times for one frame. + pub fn print_raw_with_column( + &mut self, + frame_ip: *mut c_void, + symbol_name: Option>, + filename: Option>, + lineno: Option, + colno: Option, + ) -> fmt::Result { + // Fuchsia is unable to symbolize within a process so it has a special + // format which can be used to symbolize later. Print that instead of + // printing addresses in our own format here. + if cfg!(target_os = "fuchsia") { + self.print_raw_fuchsia(frame_ip)?; + } else { + self.print_raw_generic(frame_ip, symbol_name, filename, lineno, colno)?; + } + self.symbol_index += 1; + Ok(()) + } + + #[allow(unused_mut)] + fn print_raw_generic( + &mut self, + mut frame_ip: *mut c_void, + symbol_name: Option>, + filename: Option>, + lineno: Option, + colno: Option, + ) -> fmt::Result { + // No need to print "null" frames, it basically just means that the + // system backtrace was a bit eager to trace back super far. + if let PrintFmt::Short = self.fmt.format { + if frame_ip.is_null() { + return Ok(()); + } + } + + // To reduce TCB size in Sgx enclave, we do not want to implement symbol + // resolution functionality. Rather, we can print the offset of the + // address here, which could be later mapped to correct function. + #[cfg(all(feature = "std", target_env = "sgx", target_vendor = "fortanix"))] + { + let image_base = std::os::fortanix_sgx::mem::image_base(); + frame_ip = usize::wrapping_sub(frame_ip as usize, image_base as _) as _; + } + + // Print the index of the frame as well as the optional instruction + // pointer of the frame. If we're beyond the first symbol of this frame + // though we just print appropriate whitespace. + if self.symbol_index == 0 { + write!(self.fmt.fmt, "{:4}: ", self.fmt.frame_index)?; + if let PrintFmt::Full = self.fmt.format { + write!(self.fmt.fmt, "{:1$?} - ", frame_ip, HEX_WIDTH)?; + } + } else { + write!(self.fmt.fmt, " ")?; + if let PrintFmt::Full = self.fmt.format { + write!(self.fmt.fmt, "{:1$}", "", HEX_WIDTH + 3)?; + } + } + + // Next up write out the symbol name, using the alternate formatting for + // more information if we're a full backtrace. Here we also handle + // symbols which don't have a name, + match (symbol_name, &self.fmt.format) { + (Some(name), PrintFmt::Short) => write!(self.fmt.fmt, "{:#}", name)?, + (Some(name), PrintFmt::Full) => write!(self.fmt.fmt, "{}", name)?, + (None, _) | (_, PrintFmt::__Nonexhaustive) => write!(self.fmt.fmt, "")?, + } + self.fmt.fmt.write_str("\n")?; + + // And last up, print out the filename/line number if they're available. + if let (Some(file), Some(line)) = (filename, lineno) { + self.print_fileline(file, line, colno)?; + } + + Ok(()) + } + + fn print_fileline( + &mut self, + file: BytesOrWideString<'_>, + line: u32, + colno: Option, + ) -> fmt::Result { + // Filename/line are printed on lines under the symbol name, so print + // some appropriate whitespace to sort of right-align ourselves. + if let PrintFmt::Full = self.fmt.format { + write!(self.fmt.fmt, "{:1$}", "", HEX_WIDTH)?; + } + write!(self.fmt.fmt, " at ")?; + + // Delegate to our internal callback to print the filename and then + // print out the line number. + (self.fmt.print_path)(self.fmt.fmt, file)?; + write!(self.fmt.fmt, ":{}", line)?; + + // Add column number, if available. + if let Some(colno) = colno { + write!(self.fmt.fmt, ":{}", colno)?; + } + + write!(self.fmt.fmt, "\n")?; + Ok(()) + } + + fn print_raw_fuchsia(&mut self, frame_ip: *mut c_void) -> fmt::Result { + // We only care about the first symbol of a frame + if self.symbol_index == 0 { + self.fmt.fmt.write_str("{{{bt:")?; + write!(self.fmt.fmt, "{}:{:?}", self.fmt.frame_index, frame_ip)?; + self.fmt.fmt.write_str("}}}\n")?; + } + Ok(()) + } +} + +impl Drop for BacktraceFrameFmt<'_, '_, '_> { + fn drop(&mut self) { + self.fmt.frame_index += 1; + } +} -- cgit v1.2.3