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Diffstat (limited to 'src/rust/tor_log/tor_log.rs')
| -rw-r--r-- | src/rust/tor_log/tor_log.rs | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/src/rust/tor_log/tor_log.rs b/src/rust/tor_log/tor_log.rs new file mode 100644 index 0000000000..ad6725f0f2 --- /dev/null +++ b/src/rust/tor_log/tor_log.rs @@ -0,0 +1,270 @@ +// Copyright (c) 2016-2017, The Tor Project, Inc. */ +// See LICENSE for licensing information */ + +// Note that these functions are untested due to the fact that there are no +// return variables to test and they are calling into a C API. + +/// The related domain which the logging message is relevant. For example, +/// log messages relevant to networking would use LogDomain::LdNet, whereas +/// general messages can use LdGeneral. +#[derive(Eq, PartialEq)] +pub enum LogDomain { + Net, + General, +} + +/// The severity level at which to log messages. +#[derive(Eq, PartialEq)] +pub enum LogSeverity { + Notice, + Warn, +} + +/// Main entry point for Rust modules to log messages. +/// +/// # Inputs +/// +/// * A `severity` of type LogSeverity, which defines the level of severity the +/// message will be logged. +/// * A `domain` of type LogDomain, which defines the domain the log message +/// will be associated with. +/// * A `function` of type &str, which defines the name of the function where +/// the message is being logged. There is a current RFC for a macro that +/// defines function names. When it is, we should use it. See +/// https://github.com/rust-lang/rfcs/pull/1719 +/// * A `message` of type &str, which is the log message itself. +#[macro_export] +macro_rules! tor_log_msg { + ($severity: path, + $domain: path, + $function: expr, + $($message:tt)*) => + { + { + let msg = format!($($message)*); + $crate::tor_log_msg_impl($severity, $domain, $function, msg) + } + }; +} + +#[inline] +pub fn tor_log_msg_impl( + severity: LogSeverity, + domain: LogDomain, + function: &str, + message: String, +) { + use std::ffi::CString; + + /// Default function name to log in case of errors when converting + /// a function name to a CString + const ERR_LOG_FUNCTION: &str = "tor_log_msg"; + + /// Default message to log in case of errors when converting a log + /// message to a CString + const ERR_LOG_MSG: &str = "Unable to log message from Rust \ + module due to error when converting to CString"; + + let func = match CString::new(function) { + Ok(n) => n, + Err(_) => CString::new(ERR_LOG_FUNCTION).unwrap(), + }; + + let msg = match CString::new(message) { + Ok(n) => n, + Err(_) => CString::new(ERR_LOG_MSG).unwrap(), + }; + + // Bind to a local variable to preserve ownership. This is essential so + // that ownership is guaranteed until these local variables go out of scope + let func_ptr = func.as_ptr(); + let msg_ptr = msg.as_ptr(); + + let c_severity = unsafe { log::translate_severity(severity) }; + let c_domain = unsafe { log::translate_domain(domain) }; + + unsafe { log::tor_log_string(c_severity, c_domain, func_ptr, msg_ptr) } +} + +/// This implementation is used when compiling for actual use, as opposed to +/// testing. +#[cfg(not(test))] +pub mod log { + use libc::{c_char, c_int}; + use super::LogDomain; + use super::LogSeverity; + + /// Severity log types. These mirror definitions in /src/common/torlog.h + /// C_RUST_COUPLED: src/common/log.c, log domain types + extern "C" { + static LOG_WARN_: c_int; + static LOG_NOTICE_: c_int; + } + + /// Domain log types. These mirror definitions in /src/common/torlog.h + /// C_RUST_COUPLED: src/common/log.c, log severity types + extern "C" { + static LD_NET_: u32; + static LD_GENERAL_: u32; + } + + /// Translate Rust defintions of log domain levels to C. This exposes a 1:1 + /// mapping between types. + #[inline] + pub unsafe fn translate_domain(domain: LogDomain) -> u32 { + match domain { + LogDomain::Net => LD_NET_, + LogDomain::General => LD_GENERAL_, + } + } + + /// Translate Rust defintions of log severity levels to C. This exposes a + /// 1:1 mapping between types. + #[inline] + pub unsafe fn translate_severity(severity: LogSeverity) -> c_int { + match severity { + LogSeverity::Warn => LOG_WARN_, + LogSeverity::Notice => LOG_NOTICE_, + } + } + + /// The main entry point into Tor's logger. When in non-test mode, this + /// will link directly with `tor_log_string` in /src/or/log.c + extern "C" { + pub fn tor_log_string( + severity: c_int, + domain: u32, + function: *const c_char, + string: *const c_char, + ); + } +} + +/// This module exposes no-op functionality for testing other Rust modules +/// without linking to C. +#[cfg(test)] +pub mod log { + use libc::{c_char, c_int}; + use super::LogDomain; + use super::LogSeverity; + + pub static mut LAST_LOGGED_FUNCTION: *mut String = 0 as *mut String; + pub static mut LAST_LOGGED_MESSAGE: *mut String = 0 as *mut String; + + pub unsafe fn tor_log_string( + _severity: c_int, + _domain: u32, + function: *const c_char, + message: *const c_char, + ) { + use std::ffi::CStr; + + let f = CStr::from_ptr(function); + let fct = match f.to_str() { + Ok(n) => n, + Err(_) => "", + }; + LAST_LOGGED_FUNCTION = Box::into_raw(Box::new(String::from(fct))); + + let m = CStr::from_ptr(message); + let msg = match m.to_str() { + Ok(n) => n, + Err(_) => "", + }; + LAST_LOGGED_MESSAGE = Box::into_raw(Box::new(String::from(msg))); + } + + pub unsafe fn translate_domain(_domain: LogDomain) -> u32 { + 1 + } + + pub unsafe fn translate_severity(_severity: LogSeverity) -> c_int { + 1 + } +} + +#[cfg(test)] +mod test { + use tor_log::*; + use tor_log::log::{LAST_LOGGED_FUNCTION, LAST_LOGGED_MESSAGE}; + + #[test] + fn test_get_log_message() { + { + fn test_macro() { + tor_log_msg!( + LogSeverity::Warn, + LogDomain::Net, + "test_macro", + "test log message {}", + "a", + ); + } + + test_macro(); + + let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) }; + assert_eq!("test_macro", *function); + + let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) }; + assert_eq!("test log message a", *message); + } + + // test multiple inputs into the log message + { + fn test_macro() { + tor_log_msg!( + LogSeverity::Warn, + LogDomain::Net, + "next_test_macro", + "test log message {} {} {} {} {}", + 1, + 2, + 3, + 4, + 5 + ); + } + + test_macro(); + + let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) }; + assert_eq!("next_test_macro", *function); + + let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) }; + assert_eq!("test log message 1 2 3 4 5", *message); + } + + // test how a long log message will be formatted + { + fn test_macro() { + tor_log_msg!( + LogSeverity::Warn, + LogDomain::Net, + "test_macro", + "{}", + "All the world's a stage, and all the men and women \ + merely players: they have their exits and their \ + entrances; and one man in his time plays many parts, his \ + acts being seven ages." + ); + } + + test_macro(); + + let expected_string = "All the world's a \ + stage, and all the men \ + and women merely players: \ + they have their exits and \ + their entrances; and one man \ + in his time plays many parts, \ + his acts being seven ages."; + + let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) }; + assert_eq!("test_macro", *function); + + let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) }; + assert_eq!(expected_string, *message); + } + } +} |