vendor latest containers/psgo

Signed-off-by: Valentin Rothberg <vrothberg@suse.com>

Closes: #1162
Approved by: rhatdan

vendor/github.com/containers/psgo/internal/proc/pids.go

@@ -0,0 +1,79 @@
+package proc
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// GetPIDs extracts and returns all PIDs from /proc.
+func GetPIDs() ([]string, error) {
+	procDir, err := os.Open("/proc/")
+	if err != nil {
+		return nil, err
+	}
+	defer procDir.Close()
+
+	// extract string slice of all directories in procDir
+	pidDirs, err := procDir.Readdirnames(0)
+	if err != nil {
+		return nil, err
+	}
+
+	pids := []string{}
+	for _, pidDir := range pidDirs {
+		_, err := strconv.Atoi(pidDir)
+		if err != nil {
+			// skip non-numerical entries (e.g., `/proc/softirqs`)
+			continue
+		}
+		pids = append(pids, pidDir)
+	}
+
+	return pids, nil
+}
+
+// pidCgroupPath returns the path to the pid's pids cgroup.
+func pidCgroupPath(pid string) (string, error) {
+	f, err := os.Open(fmt.Sprintf("/proc/%s/cgroup", pid))
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		fields := strings.Split(scanner.Text(), ":")
+		if len(fields) != 3 {
+			continue
+		}
+		if fields[1] == "pids" {
+			return fmt.Sprintf("/sys/fs/cgroup/pids/%s/cgroup.procs", fields[2]), nil
+		}
+	}
+	return "", fmt.Errorf("couldn't find pids group for PID %s", pid)
+}
+
+// GetPIDsFromCgroup returns a strings slice of all pids listesd in pid's pids
+// cgroup.
+func GetPIDsFromCgroup(pid string) ([]string, error) {
+	cgroupPath, err := pidCgroupPath(pid)
+	if err != nil {
+		return nil, err
+	}
+
+	f, err := os.Open(cgroupPath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	pids := []string{}
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		pids = append(pids, scanner.Text())
+	}
+	return pids, nil
+}