Özgür Kesim
647e704fed
One reason why the call to gdb might fail is that /proc/sys/kernel/yama/ptrace_scope is set to 1. We now give an corresponding hint when gdb fails.
121 lines
3.0 KiB
Go
121 lines
3.0 KiB
Go
package symbolyze
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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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"regexp"
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"strconv"
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"sync"
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"testing"
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)
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// buildSimple calls make in the testdata-directory in order to build the
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// test-binary `simple` that is linked against python3.7. If this fails, make
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// necessary adjustments to the Makefile and/or your environment and try again.
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func buildSimple() error {
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cmd := exec.Command("make", "-s")
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cmd.Dir = "testdata"
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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return cmd.Run()
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}
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// TestSimpeGDB runs the program testdata/simple multiple times and uses gdb to
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// extract the address of the symbol _PyRuntime for each pid. It compares
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// those with the results from Scanner.Run().
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func TestSimpleGDB(t *testing.T) {
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ourResults := map[int]uint64{}
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gdbResults := map[int]uint64{}
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err := buildSimple()
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if err != nil {
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t.Fatal(err)
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}
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scanner := NewScanner("_PyRuntime", "*python3*")
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var m sync.Mutex
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scanner.OnFound(func(pid int, offset uint64) error {
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t.Logf("scanner setting pid %d to offset %x", pid, offset)
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m.Lock()
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ourResults[pid] = offset
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m.Unlock()
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return nil
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})
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for i := 0; i < 5; i++ {
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simple := exec.Command("testdata/simple")
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if err := simple.Start(); err != nil {
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t.Fatal(err)
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}
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defer func() {
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simple.Process.Kill()
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simple.Wait()
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}()
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t.Logf("Asking Gdb about PID %d", simple.Process.Pid)
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offset, err := extractOffsetWithGdb(simple.Process.Pid, t)
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if err != nil {
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t.Fatalf("extractOffsetWithGdb: %v", err)
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}
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t.Logf("Found offset at 0x%x", offset)
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gdbResults[simple.Process.Pid] = offset
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}
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if err = scanner.Run(); err != nil {
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t.Logf("Scanner failure: %v", err)
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}
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for pid, off := range gdbResults {
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if off2, ok := ourResults[pid]; !ok {
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t.Fatalf("Scanner has no offset for pid %d", pid)
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} else if off != off2 {
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t.Fatalf("Scanner has found offset %d while gdb has found offset %d for pid %d", off2, off, pid)
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}
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}
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}
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// searchRX should match the output of gdb when it prints the address of the
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// symbol
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var searchRX = regexp.MustCompile(`Symbol "_PyRuntime" is static storage at address 0x([0-9a-fA-F]+)`)
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// extractOffsetWithGdb calls gdb in batch-mode on a pid and looks up the
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// address of the symbol _PyRuntime by calling `info address _PyRuntime`. If
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// found, it extracts the address from the gdb-output.
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func extractOffsetWithGdb(pid int, t *testing.T) (offset uint64, err error) {
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cmd := exec.Command("gdb",
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"--batch",
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"-p", strconv.Itoa(pid),
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"-ex", "info address _PyRuntime",
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"-ex", "quit")
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output, err := cmd.StdoutPipe()
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if err != nil {
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return 0, err
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}
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if err := cmd.Start(); err != nil {
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return 0, err
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}
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defer cmd.Wait()
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scanner := bufio.NewScanner(output)
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for scanner.Scan() {
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line := scanner.Text()
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// t.Logf("[gdb]: %v", line)
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match := searchRX.FindStringSubmatch(line)
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if len(match) > 1 {
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return strconv.ParseUint(match[1], 16, 64)
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}
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}
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return 0, fmt.Errorf("[31mSymbol not found with gdb.[0m\n" +
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"[35mMaybe /proc/sys/kernel/yama/ptrace_scope must be set to 0? Or try to run the test as root![0m")
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}
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