| 1 | package crashreport |
| 2 | |
| 3 | import ( |
| 4 | "io" |
| 5 | "os" |
| 6 | "path/filepath" |
| 7 | "runtime" |
| 8 | "runtime/debug" |
| 9 | "strconv" |
| 10 | "strings" |
| 11 | "time" |
| 12 | ) |
| 13 | |
| 14 | const ( |
| 15 | fatalDirName = "cli-crash-fatal" |
| 16 | fatalSuffix = ".log" |
| 17 | maxFatalDumpLen = 64 << 10 |
| 18 | ) |
| 19 | |
| 20 | // InstallFatalOutput mirrors what the Go runtime prints when it kills the |
| 21 | // process — a panic on any goroutine, a fatal runtime error — into a per-PID |
| 22 | // file under home, so the next start can queue it. Call release on every path |
| 23 | // that does not end in such a crash; it detaches the file and removes it. |
| 24 | func InstallFatalOutput(home string) (release func()) { |
| 25 | release = func() {} |
| 26 | if strings.TrimSpace(home) == "" { |
| 27 | return release |
| 28 | } |
| 29 | path := filepath.Join(home, fatalDirName, strconv.Itoa(os.Getpid())+fatalSuffix) |
| 30 | if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil { |
| 31 | return release |
| 32 | } |
| 33 | f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o600) |
| 34 | if err != nil { |
| 35 | return release |
| 36 | } |
| 37 | // The runtime duplicates the descriptor, so ours can close immediately. |
| 38 | installErr := debug.SetCrashOutput(f, debug.CrashOptions{}) |
| 39 | _ = f.Close() |
| 40 | if installErr != nil { |
| 41 | _ = os.Remove(path) |
| 42 | return release |
| 43 | } |
| 44 | return func() { |
| 45 | _ = debug.SetCrashOutput(nil, debug.CrashOptions{}) |
| 46 | _ = os.Remove(path) |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | // CaptureFatalDumps queues the dumps left by processes that died after |
| 51 | // InstallFatalOutput, and discards the empty files of ones killed without one. |
| 52 | func CaptureFatalDumps(home, version string) { |
| 53 | if strings.TrimSpace(home) == "" { |
| 54 | return |
| 55 | } |
| 56 | dir := filepath.Join(home, fatalDirName) |
| 57 | entries, err := os.ReadDir(dir) |
| 58 | if err != nil { |
| 59 | return |
| 60 | } |
| 61 | for _, entry := range entries { |
| 62 | pid, err := strconv.Atoi(strings.TrimSuffix(entry.Name(), fatalSuffix)) |
| 63 | if entry.IsDir() || !strings.HasSuffix(entry.Name(), fatalSuffix) || err != nil || |
| 64 | pid <= 0 || pid == os.Getpid() || processAlive(pid) { |
| 65 | continue |
| 66 | } |
| 67 | path := filepath.Join(dir, entry.Name()) |
| 68 | if captureFatalDump(home, version, path) == nil { |
| 69 | _ = os.Remove(path) |
| 70 | } |
| 71 | } |
| 72 | _ = os.Remove(dir) |
| 73 | } |
| 74 | |
| 75 | func captureFatalDump(home, version, path string) error { |
| 76 | f, err := os.Open(path) |
| 77 | if err != nil { |
| 78 | return err |
| 79 | } |
| 80 | defer f.Close() |
| 81 | occurredAt := time.Now().UTC() |
| 82 | if info, statErr := f.Stat(); statErr == nil { |
| 83 | occurredAt = info.ModTime().UTC() |
| 84 | } |
| 85 | raw, err := io.ReadAll(io.LimitReader(f, maxFatalDumpLen)) |
| 86 | if err != nil { |
| 87 | return err |
| 88 | } |
| 89 | if strings.TrimSpace(string(raw)) == "" { |
| 90 | return nil |
| 91 | } |
| 92 | classification, stack := splitFatalDump(string(raw)) |
| 93 | cleanStack := sanitizeStack(stack) |
| 94 | return write(home, Report{ |
| 95 | Kind: "crash", |
| 96 | Version: sanitizeField(defaultString(version, "unknown"), 64), |
| 97 | OS: runtime.GOOS, |
| 98 | Arch: runtime.GOARCH, |
| 99 | Message: "[cli fatal]\n\nGo runtime terminated the CLI process.", |
| 100 | SchemaVersion: currentSchemaVersion, |
| 101 | ErrorType: "GoRuntimeFatal", |
| 102 | ErrorMessage: classification, |
| 103 | Stack: cleanStack, |
| 104 | TopFrame: topFrame(cleanStack), |
| 105 | OccurredAt: occurredAt.Format(time.RFC3339Nano), |
| 106 | }) |
| 107 | } |
| 108 | |
| 109 | // splitFatalDump keeps the runtime's own classification and the goroutine |
| 110 | // stacks. A panic value is user-influenced text and never leaves the dump. |
| 111 | func splitFatalDump(raw string) (classification, stack string) { |
| 112 | const unclassified = "runtime crash output" |
| 113 | classification = unclassified |
| 114 | lines := strings.Split(raw, "\n") |
| 115 | for i, line := range lines { |
| 116 | trimmed := strings.TrimSpace(line) |
| 117 | switch { |
| 118 | case classification != unclassified && !strings.HasPrefix(trimmed, "goroutine "): |
| 119 | continue |
| 120 | case strings.HasPrefix(trimmed, "fatal error:"): |
| 121 | classification = sanitizeText(trimmed, 256) |
| 122 | case strings.HasPrefix(trimmed, "panic:"): |
| 123 | classification = "panic: [redacted panic value]" |
| 124 | case strings.HasPrefix(trimmed, "goroutine "): |
| 125 | return classification, strings.Join(lines[i:], "\n") |
| 126 | } |
| 127 | } |
| 128 | return classification, "" |
| 129 | } |
| 130 |