inspektor-gadget

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// Copyright 2023 The Inspektor Gadget authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build !withoutebpf
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package tracer
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import (
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	"bufio"
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	"fmt"
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	"os"
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	"os/exec"
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	gadgetcontext "github.com/inspektor-gadget/inspektor-gadget/pkg/gadget-context"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets"
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	"github.com/inspektor-gadget/inspektor-gadget/pkg/gadgets/script/types"
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)
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type Config struct {
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	Program string
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}
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type Tracer struct {
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	eventCallback func(ev *types.Event)
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	config        Config
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}
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func (t *Tracer) Run(gadgetCtx gadgets.GadgetContext) error {
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	params := gadgetCtx.GadgetParams()
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	t.config.Program = params.Get(ParamProgram).AsString()
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	log := gadgetCtx.Logger()
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	// TODO: Consider using CommandContext() once we support Go 1.20
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	cmd := exec.Command("bpftrace", "-e", t.config.Program)
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	stdout, err := cmd.StdoutPipe()
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	if err != nil {
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		return fmt.Errorf("getting stdout pipe: %w", err)
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	}
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	stderr, err := cmd.StderrPipe()
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	if err != nil {
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		return fmt.Errorf("getting stderr pipe: %w", err)
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	}
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	if err := cmd.Start(); err != nil {
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		return fmt.Errorf("running bpftrace: %w", err)
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	}
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	// read and send stdout as events
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	go func() {
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		scanner := bufio.NewScanner(stdout)
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		for scanner.Scan() {
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			t.eventCallback(&types.Event{
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				Output: scanner.Text(),
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			})
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		}
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		if err := scanner.Err(); err != nil {
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			log.Error("error reading bpftrace output: %s", err)
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		}
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	}()
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	// print stderr through logger
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	go func() {
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		scanner := bufio.NewScanner(stderr)
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		for scanner.Scan() {
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			log.Error(scanner.Text())
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		}
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		if err := scanner.Err(); err != nil {
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			log.Error("error reading bpftrace output: %s", err)
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		}
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	}()
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	gadgetcontext.WaitForTimeoutOrDone(gadgetCtx)
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	if err := cmd.Process.Signal(os.Interrupt); err != nil {
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		log.Errorf("failed to stop process: %s", err)
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		return nil
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	}
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	if err := cmd.Wait(); err != nil {
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		log.Errorf("failed to wait process: %s", err)
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		return nil
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	}
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	return nil
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}
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func (t *Tracer) SetEventHandler(handler any) {
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	nh, ok := handler.(func(ev *types.Event))
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	if !ok {
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		panic("event handler invalid")
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	}
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	t.eventCallback = nh
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}
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func (g *GadgetDesc) NewInstance() (gadgets.Gadget, error) {
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	return &Tracer{}, nil
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}
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