-
Notifications
You must be signed in to change notification settings - Fork 393
Expand file tree
/
Copy pathfailsafe.go
More file actions
131 lines (110 loc) · 3.17 KB
/
Copy pathfailsafe.go
File metadata and controls
131 lines (110 loc) · 3.17 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
package kvm
import (
"io"
"os"
"github.com/jetkvm/kvm/internal/failsafe"
"github.com/jetkvm/kvm/internal/sync"
)
const (
failsafeDefaultLastCrashPath = "/userdata/jetkvm/crashdump/last-crash.log"
failsafeFile = "/userdata/jetkvm/.enablefailsafe"
failsafeLastCrashEnv = "JETKVM_LAST_ERROR_PATH"
failsafeEnv = "JETKVM_FORCE_FAILSAFE"
)
var (
failsafeOnce sync.Once
failsafeCrashLog = ""
failsafeModeActive = false
failsafeModeReason = ""
)
type FailsafeModeNotification struct {
Active bool `json:"active"`
Reason string `json:"reason"`
}
// this function has side effects and can be only executed once
func checkFailsafeReason() {
failsafeOnce.Do(func() {
// check if the failsafe environment variable is set
if os.Getenv(failsafeEnv) == "1" {
failsafeModeActive = true
failsafeModeReason = "failsafe_env_set"
return
}
// check if the failsafe file exists
if _, err := os.Stat(failsafeFile); err == nil {
failsafeModeActive = true
failsafeModeReason = "failsafe_file_exists"
_ = os.Remove(failsafeFile)
return
}
// get the last crash log path from the environment variable
lastCrashPath := os.Getenv(failsafeLastCrashEnv)
if lastCrashPath == "" {
lastCrashPath = failsafeDefaultLastCrashPath
}
// check if the last crash log file exists
l := failsafeLogger.With().Str("path", lastCrashPath).Logger()
fi, err := os.Lstat(lastCrashPath)
if err != nil {
if !os.IsNotExist(err) {
l.Warn().Err(err).Msg("failed to stat last crash log")
}
return
}
if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
l.Warn().Msg("last crash log is not a symlink, ignoring")
return
}
// open the last crash log file and find if it contains the string "panic"
// read only the last 50KB to avoid memory issues with large log files
content, err := readFileTail(lastCrashPath, 50*1024)
if err != nil {
l.Warn().Err(err).Msg("failed to read last crash log")
return
}
// unlink the last crash log file
failsafeCrashLog = content
_ = os.Remove(lastCrashPath)
reason, activate := failsafe.ClassifyCrashLog(failsafeCrashLog)
if !activate {
l.Info().Str("reason", reason).Msg("last crash log does not activate failsafe mode")
return
}
failsafeModeActive = true
failsafeModeReason = reason
})
}
// readFileTail reads at most maxBytes from the end of a file.
// This prevents memory issues when reading potentially large log files.
func readFileTail(path string, maxBytes int64) (string, error) {
f, err := os.Open(path)
if err != nil {
return "", err
}
defer f.Close()
fi, err := f.Stat()
if err != nil {
return "", err
}
size := fi.Size()
if size > maxBytes {
if _, err := f.Seek(size-maxBytes, io.SeekStart); err != nil {
return "", err
}
}
data, err := io.ReadAll(f)
if err != nil {
return "", err
}
return string(data), nil
}
func notifyFailsafeMode(session *Session) {
if !failsafeModeActive || session == nil {
return
}
jsonRpcLogger.Info().Str("reason", failsafeModeReason).Msg("sending failsafe mode notification")
writeJSONRPCEvent("failsafeMode", FailsafeModeNotification{
Active: true,
Reason: failsafeModeReason,
}, session)
}