Implement API for checking if map and program types are supported (#164)

* Add helper functions for checking if map and program types are supported

Signed-off-by: grantseltzer <grantseltzer@gmail.com>

* Helper for getting section name

Signed-off-by: grantseltzer <grantseltzer@gmail.com>

libbpfgo.go

@@ -1010,6 +1010,12 @@ func (p *BPFProg) GetName() string {
 	return p.name
 }
 
+func (p *BPFProg) GetSectionName() string {
+	cs := C.bpf_program__section_name(p.prog)
+	gs := C.GoString(cs)
+	return gs
+}
+
 func (p *BPFProg) GetPinPath() string {
 	return p.pinnedPath
 }
@@ -1697,3 +1703,19 @@ func (hook *TcHook) Query(tcOpts *TcOpts) error {
 
 	return nil
 }
+
+func BPFMapTypeIsSupported(mapType MapType) (bool, error) {
+	cSupported := C.libbpf_probe_bpf_map_type(C.enum_bpf_map_type(int(mapType)), nil)
+	if cSupported < 1 {
+		return false, syscall.Errno(-cSupported)
+	}
+	return cSupported == 1, nil
+}
+
+func BPFProgramTypeIsSupported(progType BPFProgType) (bool, error) {
+	cSupported := C.libbpf_probe_bpf_prog_type(C.enum_bpf_prog_type(int(progType)), nil)
+	if cSupported < 1 {
+		return false, syscall.Errno(-cSupported)
+	}
+	return cSupported == 1, nil
+}

selftest/probe-features/Makefile

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

selftest/probe-features/go.mod

@@ -0,0 +1,7 @@
+module github.com/aquasecurity/libbpfgo/selftest/map-pin-info
+
+go 1.16
+
+require github.com/aquasecurity/libbpfgo v0.2.1-libbpf-0.4.0
+
+replace github.com/aquasecurity/libbpfgo => ../../

selftest/probe-features/go.sum

@@ -0,0 +1,11 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/sys v0.0.0-20210514084401-e8d321eab015/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

selftest/probe-features/main.bpf.c

@@ -0,0 +1,13 @@
+//+build ignore
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+
+SEC("kprobe/sys_mmap")
+int kprobe__sys_mmap(struct pt_regs *ctx)
+{
+    bpf_printk("Yankees will win the 2022 world series");
+    return 0;
+}
+
+char LICENSE[] SEC("license") = "Dual BSD/GPL";

selftest/probe-features/main.go

@@ -0,0 +1,66 @@
+package main
+
+import "C"
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/aquasecurity/libbpfgo"
+	bpf "github.com/aquasecurity/libbpfgo"
+)
+
+func main() {
+	bpfModule, err := bpf.NewModuleFromFile("main.bpf.o")
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+	defer bpfModule.Close()
+
+	kprobeProg, err := bpfModule.GetProgram("kprobe__sys_mmap")
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+
+	err = kprobeProg.SetAutoload(false)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+
+	isSupported, err := bpf.BPFProgramTypeIsSupported(libbpfgo.BPFProgTypeKprobe)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+
+	if isSupported {
+		err = kprobeProg.SetAutoload(true)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(-1)
+		}
+	}
+
+	err = bpfModule.BPFLoadObject()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+
+	isSupported, err = bpf.BPFMapTypeIsSupported(libbpfgo.MapTypeHash)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(-1)
+	}
+
+	if isSupported {
+		_, err = libbpfgo.CreateMap(libbpfgo.MapTypeHash, "foobar", 4, 4, 420, nil)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}

selftest/probe-features/run.sh

@@ -0,0 +1 @@
+../common/run.sh