Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/inputs/procstat/pgrep.go

@@ -0,0 +1,85 @@
+package procstat
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/influxdata/telegraf/internal"
+)
+
+// Implementation of PIDGatherer that execs pgrep to find processes
+type pgrep struct {
+	path string
+}
+
+func newPgrepFinder() (pidFinder, error) {
+	path, err := exec.LookPath("pgrep")
+	if err != nil {
+		return nil, fmt.Errorf("could not find pgrep binary: %w", err)
+	}
+	return &pgrep{path}, nil
+}
+
+func (*pgrep) pidFile(path string) ([]pid, error) {
+	var pids []pid
+	pidString, err := os.ReadFile(path)
+	if err != nil {
+		return pids, fmt.Errorf("failed to read pidfile %q: %w",
+			path, err)
+	}
+	processID, err := strconv.ParseInt(strings.TrimSpace(string(pidString)), 10, 32)
+	if err != nil {
+		return pids, err
+	}
+	pids = append(pids, pid(processID))
+	return pids, nil
+}
+
+func (pg *pgrep) pattern(pattern string) ([]pid, error) {
+	args := []string{pattern}
+	return pg.find(args)
+}
+
+func (pg *pgrep) uid(user string) ([]pid, error) {
+	args := []string{"-u", user}
+	return pg.find(args)
+}
+
+func (pg *pgrep) fullPattern(pattern string) ([]pid, error) {
+	args := []string{"-f", pattern}
+	return pg.find(args)
+}
+
+func (pg *pgrep) children(pid pid) ([]pid, error) {
+	args := []string{"-P", strconv.FormatInt(int64(pid), 10)}
+	return pg.find(args)
+}
+
+func (pg *pgrep) find(args []string) ([]pid, error) {
+	// Execute pgrep with the given arguments
+	buf, err := exec.Command(pg.path, args...).Output()
+	if err != nil {
+		// Exit code 1 means "no processes found" so we should not return
+		// an error in this case.
+		if status, _ := internal.ExitStatus(err); status == 1 {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("error running %q: %w", pg.path, err)
+	}
+	out := string(buf)
+
+	// Parse the command output to extract the PIDs
+	fields := strings.Fields(out)
+	pids := make([]pid, 0, len(fields))
+	for _, field := range fields {
+		processID, err := strconv.ParseInt(field, 10, 32)
+		if err != nil {
+			return nil, err
+		}
+		pids = append(pids, pid(processID))
+	}
+	return pids, nil
+}