dotcloud/docker

package system // import "github.com/docker/docker/pkg/system"

import (
    "os"
    "syscall"
    "time"
    "unsafe"
)

// Used by Chtimes
var unixEpochTime, unixMaxTime time.Time

func init() {
    unixEpochTime = time.Unix(0, 0)
    if unsafe.Sizeof(syscall.Timespec{}.Nsec) == 8 {
        // This is a 64 bit timespec
        // os.Chtimes limits time to the following
        //
        // Note that this intentionally sets nsec (not sec), which sets both sec
        // and nsec internally in time.Unix();
        // https://github.com/golang/go/blob/go1.19.2/src/time/time.go#L1364-L1380
        unixMaxTime = time.Unix(0, 1<<63-1)
    } else {
        // This is a 32 bit timespec
        unixMaxTime = time.Unix(1<<31-1, 0)
    }
}

// Chtimes changes the access time and modified time of a file at the given path.
// If the modified time is prior to the Unix Epoch (unixMinTime), or after the
// end of Unix Time (unixEpochTime), os.Chtimes has undefined behavior. In this
// case, Chtimes defaults to Unix Epoch, just in case.
func Chtimes(name string, atime time.Time, mtime time.Time) error {
    if atime.Before(unixEpochTime) || atime.After(unixMaxTime) {
        atime = unixEpochTime
    }

    if mtime.Before(unixEpochTime) || mtime.After(unixMaxTime) {
        mtime = unixEpochTime
    }

    if err := os.Chtimes(name, atime, mtime); err != nil {
        return err
    }

    // Take platform specific action for setting create time.
    return setCTime(name, mtime)
}