From e5445e5444094560c48c6908b441bcc15ad576ad Mon Sep 17 00:00:00 2001
From: Kittywhiskers Van Gogh <63189531+kittywhiskers@users.noreply.github.com>
Date: Sat, 5 Sep 2020 07:36:47 -0700
Subject: [PATCH] merge bitcoin#19866: eBPF Linux tracepoints

---
 configure.ac     | 18 ++++++++++++++++++
 src/Makefile.am  |  1 +
 src/util/trace.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 src/util/trace.h

diff --git a/configure.ac b/configure.ac
index 9442dee4b9..45bdaedc51 100644
--- a/configure.ac
+++ b/configure.ac
@@ -132,6 +132,12 @@ AC_ARG_WITH([bdb],
   [use_bdb=$withval],
   [use_bdb=auto])
 
+AC_ARG_ENABLE([ebpf],
+  [AS_HELP_STRING([--enable-ebpf],
+  [enable eBPF tracing (default is yes if sys/sdt.h is found)])],
+  [use_ebpf=$enableval],
+  [use_ebpf=yes])
+
 AC_ARG_WITH([miniupnpc],
   [AS_HELP_STRING([--with-miniupnpc],
   [enable UPNP (default is yes if libminiupnpc is found)])],
@@ -1368,6 +1374,16 @@ if test x$enable_wallet != xno; then
     fi
 fi
 
+if test x$use_ebpf != xno; then
+  AC_CHECK_HEADER([sys/sdt.h], [have_sdt=yes], [have_sdt=no])
+else
+  have_sdt=no
+fi
+
+if test x$have_sdt = xyes; then
+  AC_DEFINE([ENABLE_TRACING], [1], [Define to 1 to enable eBPF user static defined tracepoints])
+fi
+
 dnl Check for libminiupnpc (optional)
 if test x$use_upnp != xno; then
   AC_CHECK_HEADERS(
@@ -1740,6 +1756,7 @@ AM_CONDITIONAL([TARGET_WINDOWS], [test x$TARGET_OS = xwindows])
 AM_CONDITIONAL([ENABLE_WALLET],[test x$enable_wallet = xyes])
 AM_CONDITIONAL([USE_SQLITE], [test "x$use_sqlite" = "xyes"])
 AM_CONDITIONAL([USE_BDB], [test "x$use_bdb" = "xyes"])
+AM_CONDITIONAL([ENABLE_TRACING],[test x$have_sdt = xyes])
 AM_CONDITIONAL([ENABLE_TESTS],[test x$BUILD_TEST = xyes])
 AM_CONDITIONAL([ENABLE_FUZZ],[test x$enable_fuzz = xyes])
 AM_CONDITIONAL([ENABLE_FUZZ_BINARY],[test x$enable_fuzz_binary = xyes])
@@ -1905,6 +1922,7 @@ echo "  with bench    = $use_bench"
 echo "  with upnp           = $use_upnp"
 echo "  with natpmp         = $use_natpmp"
 echo "  use asm             = $use_asm"
+echo "  ebpf tracing        = $have_sdt"
 echo "  sanitizers          = $use_sanitizers"
 echo "  debug enabled       = $enable_debug"
 echo "  stacktraces enabled = $enable_stacktraces"
diff --git a/src/Makefile.am b/src/Makefile.am
index d27f3bf59b..a3cd678806 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -332,6 +332,7 @@ BITCOIN_CORE_H = \
   util/string.h \
   util/time.h \
   util/threadnames.h \
+  util/trace.h \
   util/translation.h \
   util/vector.h \
   util/url.h \
diff --git a/src/util/trace.h b/src/util/trace.h
new file mode 100644
index 0000000000..9c92cb10e7
--- /dev/null
+++ b/src/util/trace.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_TRACE_H
+#define BITCOIN_UTIL_TRACE_H
+
+#ifdef ENABLE_TRACING
+
+#include <sys/sdt.h>
+
+#define TRACE(context, event) DTRACE_PROBE(context, event)
+#define TRACE1(context, event, a) DTRACE_PROBE1(context, event, a)
+#define TRACE2(context, event, a, b) DTRACE_PROBE2(context, event, a, b)
+#define TRACE3(context, event, a, b, c) DTRACE_PROBE3(context, event, a, b, c)
+#define TRACE4(context, event, a, b, c, d) DTRACE_PROBE4(context, event, a, b, c, d)
+#define TRACE5(context, event, a, b, c, d, e) DTRACE_PROBE5(context, event, a, b, c, d, e)
+#define TRACE6(context, event, a, b, c, d, e, f) DTRACE_PROBE6(context, event, a, b, c, d, e, f)
+#define TRACE7(context, event, a, b, c, d, e, f, g) DTRACE_PROBE7(context, event, a, b, c, d, e, f, g)
+#define TRACE8(context, event, a, b, c, d, e, f, g, h) DTRACE_PROBE8(context, event, a, b, c, d, e, f, g, h)
+#define TRACE9(context, event, a, b, c, d, e, f, g, h, i) DTRACE_PROBE9(context, event, a, b, c, d, e, f, g, h, i)
+#define TRACE10(context, event, a, b, c, d, e, f, g, h, i, j) DTRACE_PROBE10(context, event, a, b, c, d, e, f, g, h, i, j)
+#define TRACE11(context, event, a, b, c, d, e, f, g, h, i, j, k) DTRACE_PROBE11(context, event, a, b, c, d, e, f, g, h, i, j, k)
+#define TRACE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l) DTRACE_PROBE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l)
+
+#else
+
+#define TRACE(context, event)
+#define TRACE1(context, event, a)
+#define TRACE2(context, event, a, b)
+#define TRACE3(context, event, a, b, c)
+#define TRACE4(context, event, a, b, c, d)
+#define TRACE5(context, event, a, b, c, d, e)
+#define TRACE6(context, event, a, b, c, d, e, f)
+#define TRACE7(context, event, a, b, c, d, e, f, g)
+#define TRACE8(context, event, a, b, c, d, e, f, g, h)
+#define TRACE9(context, event, a, b, c, d, e, f, g, h, i)
+#define TRACE10(context, event, a, b, c, d, e, f, g, h, i, j)
+#define TRACE11(context, event, a, b, c, d, e, f, g, h, i, j, k)
+#define TRACE12(context, event, a, b, c, d, e, f, g, h, i, j, k, l)
+
+#endif
+
+
+#endif /* BITCOIN_UTIL_TRACE_H */