Files
runc/libcontainer/system/proc.go
Yong Tang a83f5bac28 Fix issue in GetProcessStartTime
This fix tries to address the issue raised in docker:
https://github.com/docker/docker/issues/27540

The issue was that `GetProcessStartTime` use space `"  "`
to split the `/proc/[pid]/stat` and take the `22`th value.

However, the `2`th value is inside `(` and `)`, and could
contain space. The following are two examples:
```
ubuntu@ubuntu:~/runc$ cat /proc/90286/stat
90286 (bash) S 90271 90286 90286 34818 90286 4194560 1412 1130576 4 0 2 1 2334 438 20 0 1 0 3093098 20733952 823 18446744073709551615 1 1 0 0 0 0 0 3670020 1266777851 0 0 0 17 1 0 0 0 0 0 0 0 0 0 0 0 0 0
ubuntu@ubuntu:~/runc$ cat /proc/89653/stat
89653 (gunicorn: maste) S 89630 89653 89653 0 -1 4194560 29689 28896 0 3 146 32 76 19 20 0 1 0 2971844 52965376 3920 18446744073709551615 1 1 0 0 0 0 0 16781312 137447943 0 0 0 17 1 0 0 0 0 0 0 0 0 0 0 0 0 0
```

This fix fixes this issue by removing the prefix before `)`,
then finding the `20`th value (instead of `22`th value).

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
2016-10-20 11:34:21 -07:00

44 lines
1.4 KiB
Go

package system
import (
"io/ioutil"
"path/filepath"
"strconv"
"strings"
)
// look in /proc to find the process start time so that we can verify
// that this pid has started after ourself
func GetProcessStartTime(pid int) (string, error) {
data, err := ioutil.ReadFile(filepath.Join("/proc", strconv.Itoa(pid), "stat"))
if err != nil {
return "", err
}
return parseStartTime(string(data))
}
func parseStartTime(stat string) (string, error) {
// the starttime is located at pos 22
// from the man page
//
// starttime %llu (was %lu before Linux 2.6)
// (22) The time the process started after system boot. In kernels before Linux 2.6, this
// value was expressed in jiffies. Since Linux 2.6, the value is expressed in clock ticks
// (divide by sysconf(_SC_CLK_TCK)).
//
// NOTE:
// pos 2 could contain space and is inside `(` and `)`:
// (2) comm %s
// The filename of the executable, in parentheses.
// This is visible whether or not the executable is
// swapped out.
//
// the following is an example:
// 89653 (gunicorn: maste) S 89630 89653 89653 0 -1 4194560 29689 28896 0 3 146 32 76 19 20 0 1 0 2971844 52965376 3920 18446744073709551615 1 1 0 0 0 0 0 16781312 137447943 0 0 0 17 1 0 0 0 0 0 0 0 0 0 0 0 0 0
// get parts after last `)`:
s := strings.Split(stat, ")")
parts := strings.Split(strings.TrimSpace(s[len(s)-1]), " ")
return parts[22-3], nil // starts at 3 (after the filename pos `2`)
}