From 9c9ac55573ac33abbbbad256eda08dafba18bf9f Mon Sep 17 00:00:00 2001

From: Jerome Marchand <jmarchan@redhat.com>

Date: Thu, 29 Apr 2021 12:03:28 +0200

Subject: [PATCH 9/9] tools: Make tools rely on BTF instead of header files.

Many distribution already ship BTF and this is more robust that

parsing header files.

Fixes #1820

---

 docs/reference_guide.md | 3 ++-

 src/clang_parser.cpp    | 4 ++++

 tools/biosnoop.bt       | 5 ++++-

 tools/dcsnoop.bt        | 2 ++

 tools/mdflush.bt        | 2 ++

 tools/naptime.bt        | 2 ++

 tools/oomkill.bt        | 2 ++

 tools/runqlen.bt        | 6 ++++--

 tools/tcpaccept.bt      | 4 ++++

 tools/tcpconnect.bt     | 4 ++++

 tools/tcpdrop.bt        | 4 ++++

 tools/tcplife.bt        | 4 ++++

 tools/tcpretrans.bt     | 4 ++++

 tools/tcpsynbl.bt       | 2 ++

 14 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/docs/reference_guide.md b/docs/reference_guide.md

index 69a8ed22..11a685de 100644

--- a/docs/reference_guide.md

+++ b/docs/reference_guide.md

@@ -3455,7 +3455,8 @@ Attaching 1 probe...

 # BTF Support

 If kernel has BTF, kernel types are automatically available and there is no need to include additional headers

-to use them.

+to use them. To allow users to detect this situation in scripts, the preprocessor macro `BPFTRACE_HAVE_BTF` 

+is defined if BTF is detected. See tools/ for examples of its usage.

 Requirements for using BTF:

diff --git a/src/clang_parser.cpp b/src/clang_parser.cpp

index 20269a71..7fb39949 100644

--- a/src/clang_parser.cpp

+++ b/src/clang_parser.cpp

@@ -747,6 +747,9 @@ bool ClangParser::parse(ast::Program *program, BPFtrace &bpftrace, std::vector

     // Since we're omitting <linux/types.h> there's no reason to

     // add the wokarounds for it

     args.push_back("-D__CLANG_WORKAROUNDS_H");

+    // Let script know we have BTF -- this is useful for prewritten tools to

+    // conditionally include headers if BTF isn't available.

+    args.push_back("-DBPFTRACE_HAVE_BTF");

     if (handler.parse_file("definitions.h", input, args, input_files, false) &&

         handler.has_redefinition_error())

@@ -779,6 +782,7 @@ bool ClangParser::parse(ast::Program *program, BPFtrace &bpftrace, std::vector

     // taken from BTF. We cannot use BTF in such a case.

     args.pop_back();

     args.pop_back();

+    args.pop_back();

     input_files.back() = get_empty_btf_generated_header();

   }

diff --git a/tools/biosnoop.bt b/tools/biosnoop.bt

index aa88f4ba..33ad75de 100755

--- a/tools/biosnoop.bt

+++ b/tools/biosnoop.bt

@@ -1,5 +1,4 @@

 #!/usr/bin/env bpftrace

-#include <linux/blkdev.h>

 /*

  * biosnoop.bt   Block I/O tracing tool, showing per I/O latency.

  *               For Linux, uses bpftrace, eBPF.

@@ -11,6 +10,10 @@

  * 15-Nov-2017	Brendan Gregg	Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

+#include <linux/blkdev.h>

+#endif

+

 BEGIN

 {

 	printf("%-12s %-7s %-16s %-6s %7s\n", "TIME(ms)", "DISK", "COMM", "PID", "LAT(ms)");

diff --git a/tools/dcsnoop.bt b/tools/dcsnoop.bt

index 183f0fb5..e85ab1aa 100755

--- a/tools/dcsnoop.bt

+++ b/tools/dcsnoop.bt

@@ -15,6 +15,7 @@

  * 08-Sep-2018	Brendan Gregg	Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/fs.h>

 #include <linux/sched.h>

@@ -24,6 +25,7 @@ struct nameidata {

         struct qstr     last;

         // [...]

 };

+#endif

 BEGIN

 {

diff --git a/tools/mdflush.bt b/tools/mdflush.bt

index 541abba1..1db547f6 100755

--- a/tools/mdflush.bt

+++ b/tools/mdflush.bt

@@ -13,8 +13,10 @@

  * 08-Sep-2018	Brendan Gregg	Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/genhd.h>

 #include <linux/bio.h>

+#endif

 BEGIN

 {

diff --git a/tools/naptime.bt b/tools/naptime.bt

index eb96b677..a84652a3 100755

--- a/tools/naptime.bt

+++ b/tools/naptime.bt

@@ -13,8 +13,10 @@

  * 16-Feb-2019  Brendan Gregg   Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/time.h>

 #include <linux/sched.h>

+#endif

 BEGIN

 {

diff --git a/tools/oomkill.bt b/tools/oomkill.bt

index 6126682d..1c9b16a3 100755

--- a/tools/oomkill.bt

+++ b/tools/oomkill.bt

@@ -20,7 +20,9 @@

  * 07-Sep-2018	Brendan Gregg	Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/oom.h>

+#endif

 BEGIN

 {

diff --git a/tools/runqlen.bt b/tools/runqlen.bt

index 02d82d74..1be42adc 100755

--- a/tools/runqlen.bt

+++ b/tools/runqlen.bt

@@ -11,17 +11,19 @@

  * 07-Oct-2018	Brendan Gregg	Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/sched.h>

 // Until BTF is available, we'll need to declare some of this struct manually,

 // since it isn't available to be #included. This will need maintenance to match

 // your kernel version. It is from kernel/sched/sched.h:

-struct cfs_rq_partial {

+struct cfs_rq {

 	struct load_weight load;

 	unsigned long runnable_weight;

 	unsigned int nr_running;

 	unsigned int h_nr_running;

 };

+#endif

 BEGIN

 {

@@ -31,7 +33,7 @@ BEGIN

 profile:hz:99

 {

 	$task = (struct task_struct *)curtask;

-	$my_q = (struct cfs_rq_partial *)$task->se.cfs_rq;

+	$my_q = (struct cfs_rq *)$task->se.cfs_rq;

 	$len = $my_q->nr_running;

 	$len = $len > 0 ? $len - 1 : 0;	// subtract currently running task

 	@runqlen = lhist($len, 0, 100, 1);

diff --git a/tools/tcpaccept.bt b/tools/tcpaccept.bt

index b40a041b..2f4dfe1f 100755

--- a/tools/tcpaccept.bt

+++ b/tools/tcpaccept.bt

@@ -16,8 +16,12 @@

  * 23-Nov-2018	Dale Hamel	created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/socket.h>

 #include <net/sock.h>

+#else

+#include <sys/socket.h>

+#endif

 BEGIN

 {

diff --git a/tools/tcpconnect.bt b/tools/tcpconnect.bt

index 4ae30d65..05c3ca0e 100755

--- a/tools/tcpconnect.bt

+++ b/tools/tcpconnect.bt

@@ -19,8 +19,12 @@

  * 23-Nov-2018	Dale Hamel	created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/socket.h>

 #include <net/sock.h>

+#else

+#include <sys/socket.h>

+#endif

 BEGIN

 {

diff --git a/tools/tcpdrop.bt b/tools/tcpdrop.bt

index 79a86b08..2de3e507 100755

--- a/tools/tcpdrop.bt

+++ b/tools/tcpdrop.bt

@@ -17,8 +17,12 @@

  * 23-Nov-2018	Dale Hamel	created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/socket.h>

 #include <net/sock.h>

+#else

+#include <sys/socket.h>

+#endif

 BEGIN

 {

diff --git a/tools/tcplife.bt b/tools/tcplife.bt

index 9c0d8814..a9a054bf 100755

--- a/tools/tcplife.bt

+++ b/tools/tcplife.bt

@@ -13,10 +13,14 @@

  * 17-Apr-2019  Brendan Gregg   Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <net/tcp_states.h>

 #include <net/sock.h>

 #include <linux/socket.h>

 #include <linux/tcp.h>

+#else

+#include <sys/socket.h>

+#endif

 BEGIN

 {

diff --git a/tools/tcpretrans.bt b/tools/tcpretrans.bt

index 8b9500c0..777d78fa 100755

--- a/tools/tcpretrans.bt

+++ b/tools/tcpretrans.bt

@@ -17,8 +17,12 @@

  * 23-Nov-2018  Dale Hamel      created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <linux/socket.h>

 #include <net/sock.h>

+#else

+#include <sys/socket.h>

+#endif

 BEGIN

 {

diff --git a/tools/tcpsynbl.bt b/tools/tcpsynbl.bt

index 4b3c99c3..0570f29c 100755

--- a/tools/tcpsynbl.bt

+++ b/tools/tcpsynbl.bt

@@ -13,7 +13,9 @@

  * 19-Apr-2019  Brendan Gregg   Created this.

  */

+#ifndef BPFTRACE_HAVE_BTF

 #include <net/sock.h>

+#endif

 BEGIN

 {

-- 

2.35.3