diff options
Diffstat (limited to 'toolkit/crashreporter/process_reader/src/platform/linux.rs')
| -rw-r--r-- | toolkit/crashreporter/process_reader/src/platform/linux.rs | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/toolkit/crashreporter/process_reader/src/platform/linux.rs b/toolkit/crashreporter/process_reader/src/platform/linux.rs new file mode 100644 index 0000000000..4a87e5480b --- /dev/null +++ b/toolkit/crashreporter/process_reader/src/platform/linux.rs @@ -0,0 +1,322 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +use std::{ + cmp::min, + fs::File, + io::{BufRead, BufReader, Error}, + mem::{size_of, MaybeUninit}, + ptr::null_mut, + slice, +}; + +use crate::{ + error::{ProcessReaderError, PtraceError, ReadError}, + ProcessHandle, ProcessReader, +}; + +use goblin::elf::{ + self, + program_header::{PF_R, PT_NOTE}, + Elf, ProgramHeader, +}; +use libc::{ + c_int, c_long, c_void, pid_t, ptrace, waitpid, EINTR, PTRACE_ATTACH, PTRACE_DETACH, + PTRACE_PEEKDATA, __WALL, +}; + +impl ProcessReader { + pub fn new(process: ProcessHandle) -> Result<ProcessReader, ProcessReaderError> { + let pid: pid_t = process; + + ptrace_attach(pid)?; + + let mut status: i32 = 0; + + loop { + let res = unsafe { waitpid(pid, &mut status as *mut _, __WALL) }; + if res < 0 { + match get_errno() { + EINTR => continue, + _ => { + ptrace_detach(pid)?; + return Err(ProcessReaderError::WaitPidError); + } + } + } else { + break; + } + } + + Ok(ProcessReader { process: pid }) + } + + pub fn find_module(&self, module_name: &str) -> Result<usize, ProcessReaderError> { + let maps_file = File::open(format!("/proc/{}/maps", self.process))?; + + BufReader::new(maps_file) + .lines() + .flatten() + .map(|line| parse_proc_maps_line(&line)) + .filter_map(Result::ok) + .find_map(|(name, address)| { + if name.is_some_and(|name| name.eq(module_name)) { + Some(address) + } else { + None + } + }) + .ok_or(ProcessReaderError::ModuleNotFound) + } + + pub fn find_program_note( + &self, + module_address: usize, + note_type: u32, + note_size: usize, + ) -> Result<usize, ProcessReaderError> { + let header_bytes = self.copy_array(module_address, size_of::<elf::Header>())?; + let elf_header = Elf::parse_header(&header_bytes)?; + + let program_header_bytes = self.copy_array( + module_address + (elf_header.e_phoff as usize), + (elf_header.e_phnum as usize) * (elf_header.e_phentsize as usize), + )?; + + let mut elf = Elf::lazy_parse(elf_header)?; + let context = goblin::container::Ctx { + container: elf.header.container()?, + le: elf.header.endianness()?, + }; + + elf.program_headers = ProgramHeader::parse( + &program_header_bytes, + 0, + elf_header.e_phnum as usize, + context, + )?; + + self.find_note_in_headers(&elf, module_address, note_type, note_size) + } + + fn find_note_in_headers( + &self, + elf: &Elf, + address: usize, + note_type: u32, + note_size: usize, + ) -> Result<usize, ProcessReaderError> { + for program_header in elf.program_headers.iter() { + // We're looking for a note in the program headers, it needs to be + // readable and it needs to be at least as large as the + // requested size. + if (program_header.p_type == PT_NOTE) + && ((program_header.p_flags & PF_R) != 0 + && (program_header.p_memsz as usize >= note_size)) + { + // Iterate over the notes + let notes_address = address + program_header.p_offset as usize; + let mut notes_offset = 0; + let notes_size = program_header.p_memsz as usize; + while notes_offset < notes_size { + let note_address = notes_address + notes_offset; + if let Ok(note) = self.copy_object::<goblin::elf::note::Nhdr32>(note_address) { + if note.n_type == note_type { + return Ok(note_address); + } + + notes_offset += size_of::<goblin::elf::note::Nhdr32>() + + (note.n_descsz as usize) + + (note.n_namesz as usize); + } else { + break; + } + } + } + } + + Err(ProcessReaderError::NoteNotFound) + } + + pub fn copy_object_shallow<T>(&self, src: usize) -> Result<MaybeUninit<T>, ReadError> { + let data = self.copy_array(src, size_of::<T>())?; + let mut object = MaybeUninit::<T>::uninit(); + let uninitialized_object = uninit_as_bytes_mut(&mut object); + + for (index, &value) in data.iter().enumerate() { + uninitialized_object[index].write(value); + } + + Ok(object) + } + + pub fn copy_object<T>(&self, src: usize) -> Result<T, ReadError> { + self.copy_object_shallow(src) + .map(|object| unsafe { object.assume_init() }) + } + + pub fn copy_array<T>(&self, src: usize, num: usize) -> Result<Vec<T>, ReadError> { + let mut array = Vec::<MaybeUninit<T>>::with_capacity(num); + let num_bytes = num * size_of::<T>(); + let mut array_buffer = array.as_mut_ptr() as *mut u8; + let mut index = 0; + + while index < num_bytes { + let word = ptrace_read(self.process, src + index)?; + let len = min(size_of::<c_long>(), num_bytes - index); + let word_as_bytes = word.to_ne_bytes(); + for &byte in word_as_bytes.iter().take(len) { + unsafe { + array_buffer.write(byte); + array_buffer = array_buffer.add(1); + } + } + + index += size_of::<c_long>(); + } + + unsafe { + array.set_len(num); + Ok(std::mem::transmute(array)) + } + } +} + +impl Drop for ProcessReader { + fn drop(&mut self) { + let _ignored = ptrace_detach(self.process); + } +} + +fn parse_proc_maps_line(line: &str) -> Result<(Option<String>, usize), ProcessReaderError> { + let mut splits = line.trim().splitn(6, ' '); + let address_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + let _perms_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + let _offset_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + let _dev_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + let _inode_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + let path_str = splits + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + + let address = get_proc_maps_address(address_str)?; + + // Note that we don't care if the mapped file has been deleted because + // we're reading everything from memory. + let name = path_str + .trim_end_matches(" (deleted)") + .rsplit('/') + .next() + .map(String::from); + + Ok((name, address)) +} + +fn get_proc_maps_address(addresses: &str) -> Result<usize, ProcessReaderError> { + let begin = addresses + .split('-') + .next() + .ok_or(ProcessReaderError::ProcMapsParseError)?; + usize::from_str_radix(begin, 16).map_err(ProcessReaderError::from) +} + +fn uninit_as_bytes_mut<T>(elem: &mut MaybeUninit<T>) -> &mut [MaybeUninit<u8>] { + // SAFETY: MaybeUninit<u8> is always valid, even for padding bytes + unsafe { slice::from_raw_parts_mut(elem.as_mut_ptr() as *mut MaybeUninit<u8>, size_of::<T>()) } +} + +/*********************************************************************** + ***** libc helpers ***** + ***********************************************************************/ + +fn get_errno() -> c_int { + #[cfg(target_os = "linux")] + unsafe { + *libc::__errno_location() + } + #[cfg(target_os = "android")] + unsafe { + *libc::__errno() + } +} + +fn clear_errno() { + #[cfg(target_os = "linux")] + unsafe { + *libc::__errno_location() = 0; + } + #[cfg(target_os = "android")] + unsafe { + *libc::__errno() = 0; + } +} + +#[derive(Clone, Copy)] +enum PTraceOperation { + Attach, + Detach, + PeekData, +} + +#[cfg(all(target_os = "linux", target_env = "gnu"))] +type PTraceOperationNative = libc::c_uint; +#[cfg(all(target_os = "linux", target_env = "musl"))] +type PTraceOperationNative = libc::c_int; +#[cfg(target_os = "android")] +type PTraceOperationNative = c_int; + +impl From<PTraceOperation> for PTraceOperationNative { + fn from(val: PTraceOperation) -> Self { + match val { + PTraceOperation::Attach => PTRACE_ATTACH, + PTraceOperation::Detach => PTRACE_DETACH, + PTraceOperation::PeekData => PTRACE_PEEKDATA, + } + } +} + +fn ptrace_attach(pid: pid_t) -> Result<(), PtraceError> { + ptrace_helper(pid, PTraceOperation::Attach, 0).map(|_r| ()) +} + +fn ptrace_detach(pid: pid_t) -> Result<(), PtraceError> { + ptrace_helper(pid, PTraceOperation::Detach, 0).map(|_r| ()) +} + +fn ptrace_read(pid: libc::pid_t, addr: usize) -> Result<c_long, PtraceError> { + ptrace_helper(pid, PTraceOperation::PeekData, addr) +} + +fn ptrace_helper(pid: pid_t, op: PTraceOperation, addr: usize) -> Result<c_long, PtraceError> { + clear_errno(); + let result = unsafe { ptrace(op.into(), pid, addr, null_mut::<c_void>()) }; + + if result == -1 { + let errno = get_errno(); + if errno != 0 { + let error = match op { + PTraceOperation::Attach => PtraceError::TraceError(Error::from_raw_os_error(errno)), + PTraceOperation::Detach => PtraceError::TraceError(Error::from_raw_os_error(errno)), + PTraceOperation::PeekData => { + PtraceError::ReadError(Error::from_raw_os_error(errno)) + } + }; + Err(error) + } else { + Ok(result) + } + } else { + Ok(result) + } +} |