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feat(tracerunner): trace runner initial implementation
Signed-off-by: Lorenzo Fontana <lo@linux.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,19 @@ | ||
| package main | ||
|
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| import ( | ||
| "os" | ||
|
|
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| "github.com/fntlnz/kubectl-trace/pkg/cmd" | ||
| "github.com/spf13/pflag" | ||
| _ "k8s.io/client-go/plugin/pkg/client/auth/gcp" | ||
| ) | ||
|
|
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| func main() { | ||
| flags := pflag.NewFlagSet("trace-runner", pflag.ExitOnError) | ||
| pflag.CommandLine = flags | ||
|
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| root := cmd.NewTraceRunnerCommand() | ||
| if err := root.Execute(); err != nil { | ||
| os.Exit(1) | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,208 @@ | ||
| package cmd | ||
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| import ( | ||
| "encoding/hex" | ||
| "fmt" | ||
| "io" | ||
| "math/rand" | ||
| "os" | ||
| "os/exec" | ||
| "path" | ||
| "path/filepath" | ||
| "strings" | ||
| "syscall" | ||
|
|
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| "github.com/fntlnz/mountinfo" | ||
| "github.com/spf13/cobra" | ||
| "golang.org/x/sys/unix" | ||
| ) | ||
|
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| const runFolder = "/var/run" | ||
|
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| type TraceRunnerOptions struct { | ||
| podUID string | ||
| containerName string | ||
| inPod bool | ||
| programPath string | ||
| bpftraceBinaryPath string | ||
| } | ||
|
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| func NewTraceRunnerOptions() *TraceRunnerOptions { | ||
| return &TraceRunnerOptions{} | ||
| } | ||
|
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| func NewTraceRunnerCommand() *cobra.Command { | ||
| o := NewTraceRunnerOptions() | ||
| cmd := &cobra.Command{ | ||
| PreRunE: func(c *cobra.Command, args []string) error { | ||
| return o.Validate(c, args) | ||
| }, | ||
| RunE: func(c *cobra.Command, args []string) error { | ||
| if err := o.Complete(c, args); err != nil { | ||
| return err | ||
| } | ||
| if err := o.Run(); err != nil { | ||
| fmt.Fprintln(os.Stdout, err.Error()) | ||
| return nil | ||
| } | ||
| return nil | ||
| }, | ||
| } | ||
|
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| cmd.Flags().StringVarP(&o.containerName, "container", "c", o.containerName, "Specify the container") | ||
| cmd.Flags().StringVarP(&o.podUID, "poduid", "p", o.podUID, "Specify the pod UID") | ||
| cmd.Flags().StringVarP(&o.programPath, "program", "f", "program.bt", "Specify the bpftrace program path") | ||
| cmd.Flags().StringVarP(&o.bpftraceBinaryPath, "bpftracebinary", "b", "/bin/bpftrace", "Specify the bpftrace binary path") | ||
| cmd.Flags().BoolVar(&o.inPod, "inpod", false, "Wether or not run this bpftrace in a pod's container process namespace") | ||
| return cmd | ||
| } | ||
|
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| func (o *TraceRunnerOptions) Validate(cmd *cobra.Command, args []string) error { | ||
| // TODO(fntlnz): do some more meaningful validation here, for now just checking if they are there | ||
| if o.inPod == true && (len(o.containerName) == 0 || len(o.podUID) == 0) { | ||
| return fmt.Errorf("poduid and container must be specified when inpod=true") | ||
| } | ||
| return nil | ||
| } | ||
|
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| func (o *TraceRunnerOptions) Complete(cmd *cobra.Command, args []string) error { | ||
| return nil | ||
| } | ||
|
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| func (o *TraceRunnerOptions) Run() error { | ||
| if o.inPod == false { | ||
| c := exec.Command(o.bpftraceBinaryPath, o.programPath) | ||
| c.Stdout = os.Stdout | ||
| c.Stdin = os.Stdin | ||
| c.Stderr = os.Stderr | ||
| return c.Run() | ||
| } | ||
|
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| pid, err := findPidByPodContainer(o.podUID, o.containerName) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| if pid == nil { | ||
| return fmt.Errorf("pid not found") | ||
| } | ||
| if len(*pid) == 0 { | ||
| return fmt.Errorf("invalid pid found") | ||
| } | ||
|
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| // pid found, enter its process namespace | ||
| pidns := path.Join("/proc", *pid, "/ns/pid") | ||
| pidnsfd, err := syscall.Open(pidns, syscall.O_RDONLY, 0666) | ||
| if err != nil { | ||
| return fmt.Errorf("error retrieving process namespace %s %v", pidns, err) | ||
| } | ||
| defer syscall.Close(pidnsfd) | ||
| syscall.RawSyscall(unix.SYS_SETNS, uintptr(pidnsfd), 0, 0) | ||
|
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| rootfs := path.Join("/proc", *pid, "root") | ||
| bpftracebinaryName, err := temporaryFileName("bpftrace") | ||
| if err != nil { | ||
| return err | ||
| } | ||
| temporaryProgramName := fmt.Sprintf("%s-%s", bpftracebinaryName, "program.bt") | ||
|
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| binaryPathProcRootfs := path.Join(rootfs, bpftracebinaryName) | ||
| if err := copyFile(o.bpftraceBinaryPath, binaryPathProcRootfs, 0755); err != nil { | ||
| return err | ||
| } | ||
|
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| programPathProcRootfs := path.Join(rootfs, temporaryProgramName) | ||
| if err := copyFile(o.programPath, programPathProcRootfs, 0644); err != nil { | ||
| return err | ||
| } | ||
|
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| if err := syscall.Chroot(rootfs); err != nil { | ||
| os.Remove(binaryPathProcRootfs) | ||
| return err | ||
| } | ||
|
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| defer os.Remove(bpftracebinaryName) | ||
|
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| c := exec.Command(bpftracebinaryName, temporaryProgramName) | ||
|
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| c.Stdout = os.Stdout | ||
| c.Stdin = os.Stdin | ||
| c.Stderr = os.Stderr | ||
|
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| return c.Run() | ||
| } | ||
|
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| func copyFile(src, dest string, mode os.FileMode) error { | ||
| in, err := os.Open(src) | ||
| if err != nil { | ||
| return fmt.Errorf("bpftrace binary not found in host: %v", err) | ||
| } | ||
| defer in.Close() | ||
|
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| out, err := os.OpenFile(dest, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode) | ||
|
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| if err != nil { | ||
| return fmt.Errorf("unable to create file in destination: %v", err) | ||
| } | ||
| defer out.Close() | ||
|
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| if _, err = io.Copy(out, in); err != nil { | ||
| return fmt.Errorf("unable to copy file to destination: %v", err) | ||
| } | ||
|
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| err = out.Sync() | ||
|
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| if err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
|
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| func findPidByPodContainer(podUID, containerName string) (*string, error) { | ||
| d, err := os.Open("/proc") | ||
|
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| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| defer d.Close() | ||
|
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| for { | ||
| dirs, err := d.Readdir(10) | ||
| if err == io.EOF { | ||
| break | ||
| } | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| for _, di := range dirs { | ||
| if !di.IsDir() { | ||
| continue | ||
| } | ||
| dname := di.Name() | ||
| if dname[0] < '0' || dname[0] > '9' { | ||
| continue | ||
| } | ||
|
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| mi, err := mountinfo.GetMountInfo(path.Join("/proc", dname, "mountinfo")) | ||
| if err != nil { | ||
| continue | ||
| } | ||
|
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| for _, m := range mi { | ||
| root := m.Root | ||
| if strings.Contains(root, podUID) && strings.Contains(root, containerName) { | ||
| return &dname, nil | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
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| return nil, fmt.Errorf("no process found for specified pod and container") | ||
| } | ||
|
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| func temporaryFileName(prefix string) (string, error) { | ||
| randBytes := make([]byte, 16) | ||
| rand.Read(randBytes) | ||
| return filepath.Join(runFolder, prefix+hex.EncodeToString(randBytes)), nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1 @@ | ||
| uretprobe:/caturday:"main.counterValue" { printf("%d\n", retval) }' |