Merge pull request #1706 from Lomanic/issue1698

[process][darwin][freebsd][linux][openbsd] Make process.Children not reliant on pgrep

internal/common/common_unix.go

@@ -40,23 +40,3 @@ func CallLsofWithContext(ctx context.Context, invoke Invoker, pid int32, args ..
 	}
 	return ret, nil
 }
-
-func CallPgrepWithContext(ctx context.Context, invoke Invoker, pid int32) ([]int32, error) {
-	out, err := invoke.CommandWithContext(ctx, "pgrep", "-P", strconv.Itoa(int(pid)))
-	if err != nil {
-		return []int32{}, err
-	}
-	lines := strings.Split(string(out), "\n")
-	ret := make([]int32, 0, len(lines))
-	for _, l := range lines {
-		if len(l) == 0 {
-			continue
-		}
-		i, err := strconv.ParseInt(l, 10, 32)
-		if err != nil {
-			continue
-		}
-		ret = append(ret, int32(i))
-	}
-	return ret, nil
-}

process/process.go

@@ -18,7 +18,7 @@ import (
 
 var (
 	invoke                 common.Invoker = common.Invoke{}
-	ErrorNoChildren                       = errors.New("process does not have children")
+	ErrorNoChildren                       = errors.New("process does not have children") // Deprecated: ErrorNoChildren is never returned by process.Children(), check its returned []*Process slice length instead
 	ErrorProcessNotRunning                = errors.New("process does not exist")
 	ErrorNotPermitted                     = errors.New("operation not permitted")
 )

process/process_darwin.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"fmt"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -233,18 +234,21 @@ func convertCPUTimes(s string) (ret float64, err error) {
 }
 
 func (p *Process) ChildrenWithContext(ctx context.Context) ([]*Process, error) {
-	pids, err := common.CallPgrepWithContext(ctx, invoke, p.Pid)
+	procs, err := ProcessesWithContext(ctx)
 	if err != nil {
-		return nil, err
+		return nil, nil
 	}
-	ret := make([]*Process, 0, len(pids))
-	for _, pid := range pids {
-		np, err := NewProcessWithContext(ctx, pid)
+	ret := make([]*Process, 0, len(procs))
+	for _, proc := range procs {
+		ppid, err := proc.PpidWithContext(ctx)
 		if err != nil {
-			return nil, err
+			continue
+		}
+		if ppid == p.Pid {
+			ret = append(ret, proc)
 		}
-		ret = append(ret, np)
 	}
+	sort.Slice(ret, func(i, j int) bool { return ret[i].Pid < ret[j].Pid })
 	return ret, nil
 }
 

process/process_freebsd.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"errors"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -269,18 +270,21 @@ func (p *Process) MemoryInfoWithContext(ctx context.Context) (*MemoryInfoStat, e
 }
 
 func (p *Process) ChildrenWithContext(ctx context.Context) ([]*Process, error) {
-	pids, err := common.CallPgrepWithContext(ctx, invoke, p.Pid)
+	procs, err := ProcessesWithContext(ctx)
 	if err != nil {
-		return nil, err
+		return nil, nil
 	}
-	ret := make([]*Process, 0, len(pids))
-	for _, pid := range pids {
-		np, err := NewProcessWithContext(ctx, pid)
+	ret := make([]*Process, 0, len(procs))
+	for _, proc := range procs {
+		ppid, err := proc.PpidWithContext(ctx)
 		if err != nil {
-			return nil, err
+			continue
+		}
+		if ppid == p.Pid {
+			ret = append(ret, proc)
 		}
-		ret = append(ret, np)
 	}
+	sort.Slice(ret, func(i, j int) bool { return ret[i].Pid < ret[j].Pid })
 	return ret, nil
 }
 

process/process_linux.go

@@ -12,6 +12,7 @@ import (
 	"math"
 	"os"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -338,21 +339,34 @@ func (p *Process) PageFaultsWithContext(ctx context.Context) (*PageFaultsStat, e
 }
 
 func (p *Process) ChildrenWithContext(ctx context.Context) ([]*Process, error) {
-	pids, err := common.CallPgrepWithContext(ctx, invoke, p.Pid)
+	statFiles, err := filepath.Glob(common.HostProcWithContext(ctx, "[0-9]*/stat"))
 	if err != nil {
 		return nil, err
 	}
-	if len(pids) == 0 {
-		return nil, ErrorNoChildren
-	}
-	ret := make([]*Process, 0, len(pids))
-	for _, pid := range pids {
-		np, err := NewProcessWithContext(ctx, pid)
+	ret := make([]*Process, 0, len(statFiles))
+	for _, statFile := range statFiles {
+		statContents, err := os.ReadFile(statFile)
 		if err != nil {
-			return nil, err
+			continue
+		}
+		fields := splitProcStat(statContents)
+		pid, err := strconv.ParseInt(fields[1], 10, 32)
+		if err != nil {
+			continue
+		}
+		ppid, err := strconv.ParseInt(fields[4], 10, 32)
+		if err != nil {
+			continue
+		}
+		if int32(ppid) == p.Pid {
+			np, err := NewProcessWithContext(ctx, int32(pid))
+			if err != nil {
+				continue
+			}
+			ret = append(ret, np)
 		}
-		ret = append(ret, np)
 	}
+	sort.Slice(ret, func(i, j int) bool { return ret[i].Pid < ret[j].Pid })
 	return ret, nil
 }
 

process/process_openbsd.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 	"unsafe"
@@ -286,18 +287,21 @@ func (p *Process) MemoryInfoWithContext(ctx context.Context) (*MemoryInfoStat, e
 }
 
 func (p *Process) ChildrenWithContext(ctx context.Context) ([]*Process, error) {
-	pids, err := common.CallPgrepWithContext(ctx, invoke, p.Pid)
+	procs, err := ProcessesWithContext(ctx)
 	if err != nil {
-		return nil, err
+		return nil, nil
 	}
-	ret := make([]*Process, 0, len(pids))
-	for _, pid := range pids {
-		np, err := NewProcessWithContext(ctx, pid)
+	ret := make([]*Process, 0, len(procs))
+	for _, proc := range procs {
+		ppid, err := proc.PpidWithContext(ctx)
 		if err != nil {
-			return nil, err
+			continue
+		}
+		if ppid == p.Pid {
+			ret = append(ret, proc)
 		}
-		ret = append(ret, np)
 	}
+	sort.Slice(ret, func(i, j int) bool { return ret[i].Pid < ret[j].Pid })
 	return ret, nil
 }