55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
package chroot
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import (
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"bufio"
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"bytes"
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"context"
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"fmt"
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"os/exec"
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"regexp"
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"strings"
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"time"
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)
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func (da diskAttacher) WaitForDevice(ctx context.Context, lun int32) (device string, err error) {
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// This builder will always be running in Azure, where data disks show up
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// on scbus5 target 0. The camcontrol command always outputs LUNs in
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// unpadded hexadecimal format.
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regexStr := fmt.Sprintf(`at scbus5 target 0 lun %x \(.*?da([\d]+)`, lun)
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devRegex, err := regexp.Compile(regexStr)
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if err != nil {
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return "", err
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}
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for {
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cmd := exec.Command("camcontrol", "devlist")
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var out bytes.Buffer
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cmd.Stdout = &out
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err = cmd.Run()
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if err != nil {
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return "", err
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}
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outString := out.String()
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scanner := bufio.NewScanner(strings.NewReader(outString))
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for scanner.Scan() {
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line := scanner.Text()
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// Check if this is the correct bus, target, and LUN.
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if matches := devRegex.FindStringSubmatch(line); matches != nil {
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// If this function immediately returns, devfs won't have
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// created the device yet.
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time.Sleep(1000 * time.Millisecond)
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return fmt.Sprintf("/dev/da%s", matches[1]), nil
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}
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}
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if err = scanner.Err(); err != nil {
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return "", err
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}
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select {
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case <-time.After(100 * time.Millisecond):
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// continue
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case <-ctx.Done():
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return "", ctx.Err()
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}
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}
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}
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