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90 lines
2.0 KiB
Go
90 lines
2.0 KiB
Go
// +build linux
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package elf
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import (
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"fmt"
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"os"
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"path/filepath"
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"strings"
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"unsafe"
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"github.com/iovisor/gobpf/pkg/bpffs"
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)
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/*
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#include <linux/unistd.h>
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#include <linux/bpf.h>
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#include <stdlib.h>
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#include <unistd.h>
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extern __u64 ptr_to_u64(void *);
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int bpf_pin_object(int fd, const char *pathname)
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{
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union bpf_attr attr = {};
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attr.pathname = ptr_to_u64((void *)pathname);
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attr.bpf_fd = fd;
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return syscall(__NR_bpf, BPF_OBJ_PIN, &attr, sizeof(attr));
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}
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*/
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import "C"
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const (
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BPFDirGlobals = "globals" // as in iproute2's BPF_DIR_GLOBALS
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BPFFSPath = "/sys/fs/bpf/"
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)
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func validPinPath(PinPath string) bool {
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if !strings.HasPrefix(PinPath, BPFFSPath) {
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return false
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}
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return filepath.Clean(PinPath) == PinPath
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}
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func pinObject(fd int, pinPath string) error {
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mounted, err := bpffs.IsMounted()
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if err != nil {
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return fmt.Errorf("error checking if %q is mounted: %v", BPFFSPath, err)
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}
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if !mounted {
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return fmt.Errorf("bpf fs not mounted at %q", BPFFSPath)
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}
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err = os.MkdirAll(filepath.Dir(pinPath), 0755)
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if err != nil {
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return fmt.Errorf("error creating directory %q: %v", filepath.Dir(pinPath), err)
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}
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_, err = os.Stat(pinPath)
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if err == nil {
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return fmt.Errorf("aborting, found file at %q: %v", pinPath, err)
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}
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if err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("failed to stat %q: %v", pinPath, err)
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}
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pinPathC := C.CString(pinPath)
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defer C.free(unsafe.Pointer(pinPathC))
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ret, err := C.bpf_pin_object(C.int(fd), pinPathC)
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if ret != 0 {
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return fmt.Errorf("error pinning object to %q: %v", pinPath, err)
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}
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return nil
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}
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// PinObjectGlobal pins and object to a name in a namespaces
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// e.g. `/sys/fs/bpf/my-namespace/globals/my-name`
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func PinObjectGlobal(fd int, namespace, name string) error {
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pinPath := filepath.Join(BPFFSPath, namespace, BPFDirGlobals, name)
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return pinObject(fd, pinPath)
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}
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// PinObject pins an object to a path
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func PinObject(fd int, pinPath string) error {
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if !validPinPath(pinPath) {
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return fmt.Errorf("not a valid pin path: %s", pinPath)
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}
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return pinObject(fd, pinPath)
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}
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