From 0e84610976c3148e1912f337e1589104373f0a96 Mon Sep 17 00:00:00 2001 From: Dan Everton Date: Mon, 22 Nov 2021 11:51:45 +1000 Subject: [PATCH] Refactoring after feedback. --- aya/src/programs/probe.rs | 183 ++++++++++++-------------------- aya/src/programs/trace_point.rs | 5 +- 2 files changed, 69 insertions(+), 119 deletions(-) diff --git a/aya/src/programs/probe.rs b/aya/src/programs/probe.rs index bb92cc4c..4e0fcacc 100644 --- a/aya/src/programs/probe.rs +++ b/aya/src/programs/probe.rs @@ -1,6 +1,6 @@ use libc::pid_t; use std::{ - fs, + fs::{self, OpenOptions}, io::{self, Write}, process, }; @@ -26,6 +26,15 @@ pub enum ProbeKind { URetProbe, } +impl ProbeKind { + fn pmu(&self) -> &'static str { + match *self { + ProbeKind::KProbe | ProbeKind::KRetProbe => "kprobe", + ProbeKind::UProbe | ProbeKind::URetProbe => "uprobe", + } + } +} + pub(crate) fn attach( program_data: &mut ProgramData, kind: ProbeKind, @@ -50,46 +59,13 @@ pub(crate) fn attach( pub(crate) fn detach_debug_fs(kind: ProbeKind, event_alias: &str) -> Result<(), ProgramError> { use ProbeKind::*; - /* - * Taken from https://github.com/iovisor/bcc/blob/67f59ee80fcf5deedaacba1436d9fa09d32a16a0/src/cc/libbpf.c#L1173 - * - * For [k,u]probe created with perf_event_open (on newer kernel), it is - * not necessary to clean it up in [k,u]probe_events. We first look up - * the %s_bcc_%d line in [k,u]probe_events. If the event is not found, - * it is safe to skip the cleaning up process (write -:... to the file). - */ - - let event_type = match kind { - KProbe | KRetProbe => "kprobe", - UProbe | URetProbe => "uprobe", - }; - - let events_file_name = format!("/sys/kernel/debug/tracing/{}_events", event_type); - - let found = match kind { - KProbe | KRetProbe => { - find_in_sys_kernel_debug_tracing_events(&events_file_name, event_alias) - .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })? - } - UProbe | URetProbe => { - find_in_sys_kernel_debug_tracing_events(&events_file_name, event_alias) - .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })? - } + let _ = match kind { + KProbe | KRetProbe => delete_probe_event(kind, event_alias) + .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })?, + UProbe | URetProbe => delete_probe_event(kind, event_alias) + .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })?, }; - if found { - match kind { - KProbe | KRetProbe => { - delete_in_sys_kernel_debug_tracing_events(&events_file_name, event_alias) - .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })? - } - UProbe | URetProbe => { - delete_in_sys_kernel_debug_tracing_events(&events_file_name, event_alias) - .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })? - } - }; - } - Ok(()) } @@ -102,19 +78,19 @@ fn create_as_probe( use ProbeKind::*; let perf_ty = match kind { - KProbe | KRetProbe => read_sys_fs_perf_type("kprobe") + KProbe | KRetProbe => read_sys_fs_perf_type(kind.pmu()) .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })?, - UProbe | URetProbe => read_sys_fs_perf_type("uprobe") + UProbe | URetProbe => read_sys_fs_perf_type(kind.pmu()) .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })?, }; let ret_bit = match kind { KRetProbe => Some( - read_sys_fs_perf_ret_probe("kprobe") + read_sys_fs_perf_ret_probe(kind.pmu()) .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })?, ), URetProbe => Some( - read_sys_fs_perf_ret_probe("uprobe") + read_sys_fs_perf_ret_probe(kind.pmu()) .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })?, ), _ => None, @@ -138,20 +114,15 @@ fn create_as_trace_point( ) -> Result<(i32, String), ProgramError> { use ProbeKind::*; - let (event_type, event_alias) = match kind { - KProbe | KRetProbe => ( - "kprobes", - create_probe_event(kind, "kprobe", name, offset) - .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })?, - ), - UProbe | URetProbe => ( - "uprobes", - create_probe_event(kind, "uprobe", name, offset) - .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })?, - ), + let event_alias = match kind { + KProbe | KRetProbe => create_probe_event(kind, name, offset) + .map_err(|(filename, io_error)| KProbeError::FileError { filename, io_error })?, + UProbe | URetProbe => create_probe_event(kind, name, offset) + .map_err(|(filename, io_error)| UProbeError::FileError { filename, io_error })?, }; - let tpid = read_sys_fs_trace_point_id(event_type, &event_alias)?; + let category = format!("{}s", kind.pmu()); + let tpid = read_sys_fs_trace_point_id(&category, &event_alias)?; let fd = perf_event_open_trace_point(tpid, pid).map_err(|(_code, io_error)| { ProgramError::SyscallError { call: "perf_event_open".to_owned(), @@ -164,93 +135,69 @@ fn create_as_trace_point( fn create_probe_event( kind: ProbeKind, - event_type: &str, fn_name: &str, offset: u64, ) -> Result { use ProbeKind::*; - let events_file_name = format!("/sys/kernel/debug/tracing/{}_events", event_type); + let events_file_name = format!("/sys/kernel/debug/tracing/{}_events", kind.pmu()); let probe_type_prefix = match kind { KProbe | UProbe => 'p', KRetProbe | URetProbe => 'r', }; - let event_alias = format!("{}_{}_aya_{}", probe_type_prefix, fn_name, process::id()); - - let mut events_file = fs::OpenOptions::new() + let event_alias = format!( + "aya_{}_{}_{}_{:#x}", + process::id(), + probe_type_prefix, + fn_name, + offset + ); + let offset_suffix = match kind { + KProbe => format!("+{}", offset), + UProbe => format!(":{:#x}", offset), + _ => "".to_string(), + }; + let probe = format!( + "{}:{}s/{} {}{}\n", + probe_type_prefix, + kind.pmu(), + event_alias, + fn_name, + offset_suffix + ); + + let mut events_file = OpenOptions::new() .append(true) .open(&events_file_name) .map_err(|e| (events_file_name.clone(), e))?; - let p = match kind { - KProbe => { - if offset > 0 { - format!( - "{}:{}s/{} {}+{}", - probe_type_prefix, event_type, event_alias, fn_name, offset - ) - } else { - format!( - "{}:{}s/{} {}", - probe_type_prefix, event_type, event_alias, fn_name - ) - } - } - KRetProbe => format!( - "{}:{}s/{} {}", - probe_type_prefix, event_type, event_alias, fn_name - ), - UProbe | URetProbe => { - if offset > 0 { - format!( - "{}:{}s/{} {}:{:#x}", - probe_type_prefix, event_type, event_alias, fn_name, offset - ) - } else { - format!( - "{}:{}s/{} {}", - probe_type_prefix, event_type, event_alias, fn_name - ) - } - } - }; - events_file - .write_all(p.as_bytes()) + .write_all(probe.as_bytes()) .map_err(|e| (events_file_name.clone(), e))?; Ok(event_alias) } -fn find_in_sys_kernel_debug_tracing_events( - events_file_name: &str, - event_alias: &str, -) -> Result { - use std::io::BufRead; +fn delete_probe_event(kind: ProbeKind, event_alias: &str) -> Result<(), (String, io::Error)> { + let events_file_name = format!("/sys/kernel/debug/tracing/{}_events", kind.pmu()); - let events_file = - fs::File::open(events_file_name).map_err(|e| (events_file_name.to_string(), e))?; + let events = + fs::read_to_string(&events_file_name).map_err(|e| (events_file_name.clone(), e))?; - Ok(io::BufReader::new(events_file) - .lines() - .map(|line| line.unwrap()) - .any(|line| line.contains(event_alias))) -} + let found = events.lines().any(|line| line.contains(event_alias)); -fn delete_in_sys_kernel_debug_tracing_events( - events_file_name: &str, - event_alias: &str, -) -> Result<(), (String, io::Error)> { - let mut events_file = fs::OpenOptions::new() - .append(true) - .open(events_file_name) - .map_err(|e| (events_file_name.to_string(), e))?; + if found { + let mut events_file = OpenOptions::new() + .append(true) + .open(&events_file_name) + .map_err(|e| (events_file_name.to_string(), e))?; - let rm = format!("-:{}", event_alias); + let rm = format!("-:{}\n", event_alias); - events_file - .write_all(rm.as_bytes()) - .map_err(|e| (events_file_name.to_string(), e))?; + events_file + .write_all(rm.as_bytes()) + .map_err(|e| (events_file_name.to_string(), e))?; + } Ok(()) } diff --git a/aya/src/programs/trace_point.rs b/aya/src/programs/trace_point.rs index eba4833c..844be0b9 100644 --- a/aya/src/programs/trace_point.rs +++ b/aya/src/programs/trace_point.rs @@ -80,7 +80,10 @@ impl TracePoint { } } -pub fn read_sys_fs_trace_point_id(category: &str, name: &str) -> Result { +pub(crate) fn read_sys_fs_trace_point_id( + category: &str, + name: &str, +) -> Result { let file = format!("/sys/kernel/debug/tracing/events/{}/{}/id", category, name); let id = fs::read_to_string(&file).map_err(|io_error| TracePointError::FileError {