add 36-tracepoint-args-sched_switch-use-custom-struct

36-tracepoint-args-sched_switch-use-custom-struct/Makefile

@@ -0,0 +1 @@
+../common/Makefile

36-tracepoint-args-sched_switch-use-custom-struct/README.md

@@ -0,0 +1,18 @@
+
+https://mozillazg.com/2022/05/ebpf-libbpf-tracepoint-common-questions.html
+
+## Usage
+
+build:
+
+```
+$ make
+```
+
+run:
+
+```
+$ make run
+
+$ make cat
+```

36-tracepoint-args-sched_switch-use-custom-struct/cilium-ebpf/Makefile

@@ -0,0 +1 @@
+../../common/cilium-ebpf.Makefile

36-tracepoint-args-sched_switch-use-custom-struct/cilium-ebpf/README.md

@@ -0,0 +1,17 @@
+
+
+## Usage
+
+build:
+
+```
+$ make
+```
+
+run:
+
+```
+$ make run
+
+$ make cat
+```

36-tracepoint-args-sched_switch-use-custom-struct/cilium-ebpf/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"log"
+	"time"
+
+	"github.com/cilium/ebpf/link"
+	"github.com/cilium/ebpf/rlimit"
+)
+
+// $BPF_CLANG and $BPF_CFLAGS are set by the Makefile
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS bpf ../main.bpf.c -- -I../ -I../output
+
+func main() {
+	if err := rlimit.RemoveMemlock(); err != nil {
+		log.Fatal(err)
+	}
+
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		log.Fatal(err)
+	}
+	defer objs.Close()
+
+	tp, err := link.Tracepoint("sched", "sched_switch", objs.TracepointSchedSchedSwitch, nil)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	defer tp.Close()
+
+	log.Println("Waiting for events...")
+	time.Sleep(time.Minute * 1024)
+
+}

36-tracepoint-args-sched_switch-use-custom-struct/main.bpf.c

@@ -0,0 +1,29 @@
+#include "vmlinux.h"
+
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+// sudo cat /sys/kernel/debug/tracing/events/sched/sched_switch/format
+struct sched_switch_args {
+    char _[8];
+    char prev_comm[16];
+    pid_t prev_pid;
+    int prev_prio;
+    long prev_state;
+    char next_comm[16];
+    pid_t next_pid;
+    int next_prio;
+};
+
+SEC("tracepoint/sched/sched_switch")
+int tracepoint__sched__sched_switch(struct sched_switch_args *ctx) {
+    u32 prev_pid = (u32)ctx->prev_pid;
+    u32 next_pid = (u32)ctx->next_pid;
+
+    char fmt[] = "sched_switch %d -> %d\n";
+    bpf_trace_printk(fmt, sizeof(fmt), prev_pid, next_pid);
+    return 0;
+}
+
+char _license[] SEC("license") = "GPL";

36-tracepoint-args-sched_switch-use-custom-struct/main.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	bpf "github.com/aquasecurity/libbpfgo"
+)
+
+func main() {
+	bpfModule, err := bpf.NewModuleFromFile("main.bpf.o")
+	if err != nil {
+		panic(err)
+	}
+	defer bpfModule.Close()
+
+	if err := bpfModule.BPFLoadObject(); err != nil {
+		panic(err)
+	}
+	prog, err := bpfModule.GetProgram("tracepoint__sched__sched_switch")
+	if err != nil {
+		panic(err)
+	}
+	if _, err := prog.AttachTracepoint("sched", "sched_switch"); err != nil {
+		panic(err)
+	}
+
+	for {
+		fmt.Println("Waiting...")
+		time.Sleep(10 * time.Second)
+	}
+}

README.rst

@@ -154,7 +154,7 @@ Examples by program type:
 | ``BPF_PROG_TYPE_SYSCALL``                 |                                        | ``syscall``                      |                       |
 +-------------------------------------------+----------------------------------------+----------------------------------+-----------------------+
 | ``BPF_PROG_TYPE_TRACEPOINT``              |                                        | ``tp+``                          |`04`_ `07`_ `14`_      |
-+                                           +                                        +----------------------------------+                       +
++                                           +                                        +----------------------------------+`35`_ `36`_            +
 |                                           |                                        | ``tracepoint+``                  |                       |
 +-------------------------------------------+----------------------------------------+----------------------------------+-----------------------+
 | ``BPF_PROG_TYPE_TRACING``                 | ``BPF_MODIFY_RETURN``                  | ``fmod_ret+``                    |                       |
@@ -212,6 +212,8 @@ Examples by program type:
 .. _32: 32-fentry-hello
 .. _33: 33-xdp-hello
 .. _34: 34-iter-task-hello
+.. _35: 35-tracepoint-args-use-custom-struct
+.. _36: 36-tracepoint-args-sched_switch-use-custom-struct
 
 
 https://mozillazg.com/tag/libbpf.html