From 8b96d2e9e28705f00067e1c7ae9be0cf9fc003eb Mon Sep 17 00:00:00 2001
From: Lomanic <5020919+Lomanic@users.noreply.github.com>
Date: Sat, 1 Jul 2023 14:51:27 +0200
Subject: [PATCH] [process][posix] Realign process.Name() with python psutil to
 return same value on python3 scripts processes

e2c79a1 started to blindly set the process name to the full path (instead of the basename) of the cmdline exectuable
if the process name from the process comm was truncated on linux. Python psutil never did that, and this is just wrong
for python (or any executable interpreted script) where the process name is not the interpreter binary but the script
itself.

A new test to check process name value against psutil value is added here, which would hopefully catch any potential
future changes in psutil.

Reverts #542

Fixes #1485
---
 process/process_darwin.go  |  2 --
 process/process_freebsd.go |  2 --
 process/process_linux.go   |  2 --
 process/process_openbsd.go |  2 --
 process/process_test.go    | 57 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 57 insertions(+), 8 deletions(-)

diff --git a/process/process_darwin.go b/process/process_darwin.go
index 55c31962a..176661cbd 100644
--- a/process/process_darwin.go
+++ b/process/process_darwin.go
@@ -82,8 +82,6 @@ func (p *Process) NameWithContext(ctx context.Context) (string, error) {
 			extendedName := filepath.Base(cmdName)
 			if strings.HasPrefix(extendedName, p.name) {
 				name = extendedName
-			} else {
-				name = cmdName
 			}
 		}
 	}
diff --git a/process/process_freebsd.go b/process/process_freebsd.go
index a123ccf9b..85134b7ee 100644
--- a/process/process_freebsd.go
+++ b/process/process_freebsd.go
@@ -55,8 +55,6 @@ func (p *Process) NameWithContext(ctx context.Context) (string, error) {
 			extendedName := filepath.Base(cmdlineSlice[0])
 			if strings.HasPrefix(extendedName, p.name) {
 				name = extendedName
-			} else {
-				name = cmdlineSlice[0]
 			}
 		}
 	}
diff --git a/process/process_linux.go b/process/process_linux.go
index 29c447390..37cb7ca44 100644
--- a/process/process_linux.go
+++ b/process/process_linux.go
@@ -845,8 +845,6 @@ func (p *Process) fillFromStatusWithContext(ctx context.Context) error {
 					extendedName := filepath.Base(cmdlineSlice[0])
 					if strings.HasPrefix(extendedName, p.name) {
 						p.name = extendedName
-					} else {
-						p.name = cmdlineSlice[0]
 					}
 				}
 			}
diff --git a/process/process_openbsd.go b/process/process_openbsd.go
index cbb1a77f6..a58c5eb11 100644
--- a/process/process_openbsd.go
+++ b/process/process_openbsd.go
@@ -60,8 +60,6 @@ func (p *Process) NameWithContext(ctx context.Context) (string, error) {
 			extendedName := filepath.Base(cmdlineSlice[0])
 			if strings.HasPrefix(extendedName, p.name) {
 				name = extendedName
-			} else {
-				name = cmdlineSlice[0]
 			}
 		}
 	}
diff --git a/process/process_test.go b/process/process_test.go
index 15e2327a1..9281c93c3 100644
--- a/process/process_test.go
+++ b/process/process_test.go
@@ -1,6 +1,7 @@
 package process
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -391,6 +392,62 @@ func Test_Process_Long_Name(t *testing.T) {
 	cmd.Process.Kill()
 }
 
+func Test_Process_Name_Against_Python(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("only applies to posix")
+	}
+	py3Path, err := exec.LookPath("python3")
+	if err != nil {
+		t.Skipf("python3 not found: %s", err)
+	}
+	if out, err := exec.Command(py3Path, "-c", "import psutil").CombinedOutput(); err != nil {
+		t.Skipf("psutil not found for %s: %s", py3Path, out)
+	}
+
+	tmpdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("unable to create temp dir %v", err)
+	}
+	defer os.RemoveAll(tmpdir) // clean up
+	tmpfilepath := filepath.Join(tmpdir, "looooooooooooooooooooong.py")
+	tmpfile, err := os.Create(tmpfilepath)
+	if err != nil {
+		t.Fatalf("unable to create temp file %v", err)
+	}
+	tmpfilecontent := []byte("#!" + py3Path + "\nimport psutil, time\nprint(psutil.Process().name(), flush=True)\nwhile True:\n\ttime.sleep(1)")
+	if _, err := tmpfile.Write(tmpfilecontent); err != nil {
+		tmpfile.Close()
+		t.Fatalf("unable to write temp file %v", err)
+	}
+	if err := tmpfile.Chmod(0o744); err != nil {
+		t.Fatalf("unable to chmod u+x temp file %v", err)
+	}
+	if err := tmpfile.Close(); err != nil {
+		t.Fatalf("unable to close temp file %v", err)
+	}
+	cmd := exec.Command(tmpfilepath)
+	outPipe, _ := cmd.StdoutPipe()
+	scanner := bufio.NewScanner(outPipe)
+	cmd.Start()
+	defer cmd.Process.Kill()
+	scanner.Scan()
+	pyName := scanner.Text() // first line printed by py3 script, its name
+	t.Logf("pyName %s", pyName)
+	p, err := NewProcess(int32(cmd.Process.Pid))
+	skipIfNotImplementedErr(t, err)
+	if err != nil {
+		t.Fatalf("getting process error %v", err)
+	}
+	name, err := p.Name()
+	skipIfNotImplementedErr(t, err)
+	if err != nil {
+		t.Fatalf("getting name error %v", err)
+	}
+	if pyName != name {
+		t.Fatalf("psutil and gopsutil process.Name() results differ: expected %s, got %s", pyName, name)
+	}
+}
+
 func Test_Process_Exe(t *testing.T) {
 	p := testGetProcess()