69 lines
2.0 KiB
Go
69 lines
2.0 KiB
Go
package backuptar
|
|
|
|
import (
|
|
"archive/tar"
|
|
"fmt"
|
|
"strconv"
|
|
"strings"
|
|
"time"
|
|
)
|
|
|
|
// Functions copied from https://github.com/golang/go/blob/master/src/archive/tar/strconv.go
|
|
// as we need to manage the LIBARCHIVE.creationtime PAXRecord manually.
|
|
// Idea taken from containerd which did the same thing.
|
|
|
|
// parsePAXTime takes a string of the form %d.%d as described in the PAX
|
|
// specification. Note that this implementation allows for negative timestamps,
|
|
// which is allowed for by the PAX specification, but not always portable.
|
|
func parsePAXTime(s string) (time.Time, error) {
|
|
const maxNanoSecondDigits = 9
|
|
|
|
// Split string into seconds and sub-seconds parts.
|
|
ss, sn := s, ""
|
|
if pos := strings.IndexByte(s, '.'); pos >= 0 {
|
|
ss, sn = s[:pos], s[pos+1:]
|
|
}
|
|
|
|
// Parse the seconds.
|
|
secs, err := strconv.ParseInt(ss, 10, 64)
|
|
if err != nil {
|
|
return time.Time{}, tar.ErrHeader
|
|
}
|
|
if len(sn) == 0 {
|
|
return time.Unix(secs, 0), nil // No sub-second values
|
|
}
|
|
|
|
// Parse the nanoseconds.
|
|
if strings.Trim(sn, "0123456789") != "" {
|
|
return time.Time{}, tar.ErrHeader
|
|
}
|
|
if len(sn) < maxNanoSecondDigits {
|
|
sn += strings.Repeat("0", maxNanoSecondDigits-len(sn)) // Right pad
|
|
} else {
|
|
sn = sn[:maxNanoSecondDigits] // Right truncate
|
|
}
|
|
nsecs, _ := strconv.ParseInt(sn, 10, 64) // Must succeed
|
|
if len(ss) > 0 && ss[0] == '-' {
|
|
return time.Unix(secs, -1*nsecs), nil // Negative correction
|
|
}
|
|
return time.Unix(secs, nsecs), nil
|
|
}
|
|
|
|
// formatPAXTime converts ts into a time of the form %d.%d as described in the
|
|
// PAX specification. This function is capable of negative timestamps.
|
|
func formatPAXTime(ts time.Time) (s string) {
|
|
secs, nsecs := ts.Unix(), ts.Nanosecond()
|
|
if nsecs == 0 {
|
|
return strconv.FormatInt(secs, 10)
|
|
}
|
|
|
|
// If seconds is negative, then perform correction.
|
|
sign := ""
|
|
if secs < 0 {
|
|
sign = "-" // Remember sign
|
|
secs = -(secs + 1) // Add a second to secs
|
|
nsecs = -(nsecs - 1e9) // Take that second away from nsecs
|
|
}
|
|
return strings.TrimRight(fmt.Sprintf("%s%d.%09d", sign, secs, nsecs), "0")
|
|
}
|