[tor-commits] [tor/master] trace: Emit a warning if tracing is built in
nickm at torproject.org
nickm at torproject.org
Fri Jul 10 17:05:59 UTC 2020
commit b049cc3ace18dd42493ca768cf4636dfd89569fc
Author: David Goulet <dgoulet at torproject.org>
Date: Wed Mar 11 12:12:28 2020 -0400
trace: Emit a warning if tracing is built in
Built in tracing should _not_ be run if it was not set on purpose. Warn as
loud as we can in order to inform the user that they are running a version
with tracing capabilities built in.
This commit also adds a subsys stub because utlimately the logging will happen
in the init phase but because the default log file is not set in the
sys_logging init function, the stub is not useful for now.
Signed-off-by: David Goulet <dgoulet at torproject.org>
---
configure.ac | 7 ++++++-
src/app/main/main.c | 4 ++++
src/lib/trace/include.am | 4 ++++
src/lib/trace/trace.h | 21 +++++++++++++++++++++
src/lib/trace/trace_stub.c | 19 +++++++++++++++++++
src/lib/trace/trace_sys.c | 5 ++++-
src/lib/trace/trace_sys.h | 8 ++++++++
7 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/configure.ac b/configure.ac
index cd014268b..75fd709f9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -273,9 +273,9 @@ if test "x$enable_tracing_instrumentation_lttng" = "xyes"; then
On Debian, apt install liblttng-ust-dev"])], [])
AC_DEFINE([USE_TRACING_INSTRUMENTATION_LTTNG], [1], [Using LTTng instrumentation])
TOR_TRACE_LIBS="-llttng-ust -ldl"
+ have_tracing=1
fi
-
dnl USDT instrumentation option.
AC_ARG_ENABLE(tracing-instrumentation-usdt,
AS_HELP_STRING([--enable-tracing-instrumentation-usdt],
@@ -291,6 +291,7 @@ if test "x$enable_tracing_instrumentation_usdt" = "xyes"; then
dnl --with-sdt. There is unfortunately no way to check that so we always
dnl build the USDT probes even though LTTng instrumentation was requested.
AC_DEFINE([USE_TRACING_INSTRUMENTATION_USDT], [1], [Using USDT instrumentation])
+ have_tracing=1
fi
dnl Tracepoints event to debug logs.
@@ -301,6 +302,9 @@ AC_ARG_ENABLE(tracing-instrumentation-log-debug,
[Tracepoints to log debug]), [])
AM_CONDITIONAL([USE_TRACING_INSTRUMENTATION_LOG_DEBUG],
[test "x$enable_tracing_instrumentation_log_debug" = "xyes"])
+if test "x$enable_tracing_instrumentation_log_debug" = "xyes"; then
+ have_tracing=1
+fi
dnl Define that tracing is supported if any instrumentation is used.
AM_COND_IF([USE_TRACING_INSTRUMENTATION_LOG_DEBUG],
@@ -309,6 +313,7 @@ AM_COND_IF([USE_TRACING_INSTRUMENTATION_USDT],
AC_DEFINE([HAVE_TRACING], [1], [Compiled with tracing support]))
AM_COND_IF([USE_TRACING_INSTRUMENTATION_LTTNG],
AC_DEFINE([HAVE_TRACING], [1], [Compiled with tracing support]))
+AM_CONDITIONAL([USE_TRACING], [test "x$have_tracing" = x1 ])
dnl Finally, define the trace libs.
AC_SUBST([TOR_TRACE_LIBS])
diff --git a/src/app/main/main.c b/src/app/main/main.c
index 89ba78742..e1d5772e3 100644
--- a/src/app/main/main.c
+++ b/src/app/main/main.c
@@ -59,6 +59,7 @@
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_s2k.h"
#include "lib/net/resolve.h"
+#include "lib/trace/trace.h"
#include "lib/process/waitpid.h"
#include "lib/pubsub/pubsub_build.h"
@@ -602,6 +603,9 @@ tor_init(int argc, char *argv[])
rust_log_welcome_string();
#endif /* defined(HAVE_RUST) */
+ /* Warn _if_ the tracing subsystem is built in. */
+ tracing_log_warning();
+
int init_rv = options_init_from_torrc(argc,argv);
if (init_rv < 0) {
log_err(LD_CONFIG,"Reading config failed--see warnings above.");
diff --git a/src/lib/trace/include.am b/src/lib/trace/include.am
index 844033132..6fe136565 100644
--- a/src/lib/trace/include.am
+++ b/src/lib/trace/include.am
@@ -26,6 +26,10 @@ if USE_TRACING_INSTRUMENTATION_LTTNG
include src/lib/trace/lttng/include.am
endif
+if USE_TRACING
src_lib_libtor_trace_a_SOURCES = $(LIBTOR_TRACE_A_SOURCES)
+else
+src_lib_libtor_trace_a_SOURCES = src/lib/trace/trace_stub.c
+endif
noinst_HEADERS+= $(TRACEHEADERS)
diff --git a/src/lib/trace/trace.h b/src/lib/trace/trace.h
index 94cbbc1e4..22589dbe9 100644
--- a/src/lib/trace/trace.h
+++ b/src/lib/trace/trace.h
@@ -9,7 +9,28 @@
#ifndef TOR_LIB_TRACE_TRACE_H
#define TOR_LIB_TRACE_TRACE_H
+#include "orconfig.h"
+
void tor_trace_init(void);
void tor_trace_free_all(void);
+#ifdef HAVE_TRACING
+
+#include "lib/log/log.h"
+
+static inline void
+tracing_log_warning(void)
+{
+ log_warn(LD_GENERAL,
+ "Tracing capabilities have been built in. If this is NOT on "
+ "purpose, your tor is NOT safe to run.");
+}
+
+#else
+
+/* NOP it. */
+#define tracing_log_warning()
+
+#endif /* defined(HAVE_TRACING) */
+
#endif /* !defined(TOR_LIB_TRACE_TRACE_H) */
diff --git a/src/lib/trace/trace_stub.c b/src/lib/trace/trace_stub.c
new file mode 100644
index 000000000..9043efe36
--- /dev/null
+++ b/src/lib/trace/trace_stub.c
@@ -0,0 +1,19 @@
+/* Copyright (c) 2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file trace_stub.c
+ * \brief Stub declaratinos for use when trace library is disabled.
+ **/
+
+#include "lib/subsys/subsys.h"
+
+#include "lib/trace/trace_sys.h"
+
+const subsys_fns_t sys_tracing = {
+ SUBSYS_DECLARE_LOCATION(),
+
+ .name = "tracing",
+ .supported = false,
+ .level = TRACE_SUBSYS_LEVEL,
+};
diff --git a/src/lib/trace/trace_sys.c b/src/lib/trace/trace_sys.c
index d6e59f4c3..2ba025840 100644
--- a/src/lib/trace/trace_sys.c
+++ b/src/lib/trace/trace_sys.c
@@ -25,9 +25,12 @@ subsys_tracing_shutdown(void)
}
const subsys_fns_t sys_tracing = {
+ SUBSYS_DECLARE_LOCATION(),
+
.name = "tracing",
.supported = true,
- .level = -85,
+ .level = TRACE_SUBSYS_LEVEL,
+
.initialize = subsys_tracing_initialize,
.shutdown = subsys_tracing_shutdown,
};
diff --git a/src/lib/trace/trace_sys.h b/src/lib/trace/trace_sys.h
index e9c97c08f..d4da5a970 100644
--- a/src/lib/trace/trace_sys.h
+++ b/src/lib/trace/trace_sys.h
@@ -11,4 +11,12 @@
extern const struct subsys_fns_t sys_tracing;
+/**
+ * Subsystem level for the tracing system.
+ *
+ * Defined here so that it can be shared between the real and stub
+ * definitions.
+ **/
+#define TRACE_SUBSYS_LEVEL (-85)
+
#endif /* !defined(TOR_TRACE_SYS_H) */
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