/
sysdep_posix.go
78 lines (72 loc) · 1.86 KB
/
sysdep_posix.go
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
// +build !windows,!plan9
package cldiag
import (
"fmt"
"log/syslog"
"os"
"strings"
"syscall"
)
var altDest *os.File
// WriteMessage2 writes an informational message (as opposed to a warning or
// fatal error message), with an optional tag between the prefix and the ":".
//
func WriteMessage2(tag, format string, v ...interface{}) {
t := new(strings.Builder)
t.WriteString(msgPrefix)
if tag == "" {
t.WriteRune(' ')
t.WriteString(tag)
}
fmt.Fprintf(t, ": "+format+"\n", v...)
text := t.String()
if l := len(text); text[l-2] == '\n' {
text = text[:l-1]
}
t = nil
verb := "write to"
if altDest == nil { // this is the usual case
_, err := os.Stderr.WriteString(text)
if err != nil {
err = TidyError(err)
} else {
err = os.Stderr.Sync()
if err != nil {
err = TidyError(err)
if err == syscall.EINVAL {
// For un-Sync-able files: pipe, FIFO, sockets, …
err = nil
} else {
verb = "sync"
}
}
}
if err == nil {
return // Message successfully written via stderr and synced.
}
// Oops! Use /dev/tty instead of os.Stderr for this and future messages.
var err2 error
altDest, err2 = os.OpenFile("/dev/tty", os.O_WRONLY, 0666)
if err2 != nil {
// “We're all going to die” ... err, panic().
syslogWriter, err3 :=
syslog.Dial("", "", syslog.LOG_CRIT, os.Args[0])
text2 := fmt.Sprintf(
"can neither %s stderr (%s) nor open /dev/tty (%s)",
verb, err, err2)
if err3 != nil {
// AFAICT, this should not happen.
panic(fmt.Sprintf("%s PANIC: %s to report: %s",
os.Args[0], text2, text))
}
fmt.Fprintf(syslogWriter, "%s to report: %s",
text2, text[:len(text)-1])
panic(fmt.Sprintf("%s PANIC: %s: more in syslog",
os.Args[0], text2))
}
fmt.Fprintf(altDest,
"%s: cannot %s stderr (%s), using /dev/tty instead\n",
os.Args[0], verb, err)
}
altDest.WriteString(text)
}