From 1d04e8641d4abab6ce978bc2dc5523c2ddb2f628 Mon Sep 17 00:00:00 2001
From: zeripath <art27@cantab.net>
Date: Fri, 3 Jun 2022 15:36:18 +0100
Subject: [PATCH] Set Setpgid on child git processes (#19865)

When Gitea is running as PID 1 git will occassionally orphan child processes leading
to (defunct) processes. This PR simply sets Setpgid to true on these child processes
meaning that these defunct processes will also be correctly reaped.

Fix #19077

Signed-off-by: Andrew Thornton <art27@cantab.net>
---
 cmd/serv.go                         |  2 ++
 modules/git/blame.go                |  1 +
 modules/git/command.go              |  1 +
 modules/markup/external/external.go |  2 ++
 modules/process/manager_exec.go     |  1 +
 modules/process/manager_unix.go     | 18 ++++++++++++++++++
 modules/process/manager_windows.go  | 16 ++++++++++++++++
 modules/ssh/ssh.go                  |  2 ++
 services/mailer/mailer.go           |  1 +
 9 files changed, 44 insertions(+)
 create mode 100644 modules/process/manager_unix.go
 create mode 100644 modules/process/manager_windows.go

diff --git a/cmd/serv.go b/cmd/serv.go
index adfbc6024..6ba3e9de0 100644
--- a/cmd/serv.go
+++ b/cmd/serv.go
@@ -24,6 +24,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/pprof"
 	"code.gitea.io/gitea/modules/private"
+	"code.gitea.io/gitea/modules/process"
 	repo_module "code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/services/lfs"
@@ -306,6 +307,7 @@ func runServ(c *cli.Context) error {
 		}
 	}
 
+	process.SetSysProcAttribute(gitcmd)
 	gitcmd.Dir = setting.RepoRootPath
 	gitcmd.Stdout = os.Stdout
 	gitcmd.Stdin = os.Stdin
diff --git a/modules/git/blame.go b/modules/git/blame.go
index 40e3d4e88..1653ecbf8 100644
--- a/modules/git/blame.go
+++ b/modules/git/blame.go
@@ -124,6 +124,7 @@ func createBlameReader(ctx context.Context, dir string, command ...string) (*Bla
 	cmd := exec.CommandContext(ctx, command[0], command[1:]...)
 	cmd.Dir = dir
 	cmd.Stderr = os.Stderr
+	process.SetSysProcAttribute(cmd)
 
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
diff --git a/modules/git/command.go b/modules/git/command.go
index 3dd12e421..f6344dbfd 100644
--- a/modules/git/command.go
+++ b/modules/git/command.go
@@ -157,6 +157,7 @@ func (c *Command) Run(opts *RunOpts) error {
 		"GIT_NO_REPLACE_OBJECTS=1",
 	)
 
+	process.SetSysProcAttribute(cmd)
 	cmd.Dir = opts.Dir
 	cmd.Stdout = opts.Stdout
 	cmd.Stderr = opts.Stderr
diff --git a/modules/markup/external/external.go b/modules/markup/external/external.go
index 4fdd4315b..a587abcc3 100644
--- a/modules/markup/external/external.go
+++ b/modules/markup/external/external.go
@@ -124,6 +124,8 @@ func (p *Renderer) Render(ctx *markup.RenderContext, input io.Reader, output io.
 		cmd.Stdin = input
 	}
 	cmd.Stdout = output
+	process.SetSysProcAttribute(cmd)
+
 	if err := cmd.Run(); err != nil {
 		return fmt.Errorf("%s render run command %s %v failed: %v", p.Name(), commands[0], args, err)
 	}
diff --git a/modules/process/manager_exec.go b/modules/process/manager_exec.go
index 61ddae646..77e3d3193 100644
--- a/modules/process/manager_exec.go
+++ b/modules/process/manager_exec.go
@@ -58,6 +58,7 @@ func (pm *Manager) ExecDirEnvStdIn(ctx context.Context, timeout time.Duration, d
 	if stdIn != nil {
 		cmd.Stdin = stdIn
 	}
+	SetSysProcAttribute(cmd)
 
 	if err := cmd.Start(); err != nil {
 		return "", "", err
diff --git a/modules/process/manager_unix.go b/modules/process/manager_unix.go
new file mode 100644
index 000000000..1e7c77fdb
--- /dev/null
+++ b/modules/process/manager_unix.go
@@ -0,0 +1,18 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//go:build !windows
+
+package process
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// SetSysProcAttribute sets the common SysProcAttrs for commands
+func SetSysProcAttribute(cmd *exec.Cmd) {
+	// When Gitea runs SubProcessA -> SubProcessB and SubProcessA gets killed by context timeout, use setpgid to make sure the sub processes can be reaped instead of leaving defunct(zombie) processes.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+}
diff --git a/modules/process/manager_windows.go b/modules/process/manager_windows.go
new file mode 100644
index 000000000..35f66d9fa
--- /dev/null
+++ b/modules/process/manager_windows.go
@@ -0,0 +1,16 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//go:build windows
+
+package process
+
+import (
+	"os/exec"
+)
+
+// SetSysProcAttribute sets the common SysProcAttrs for commands
+func SetSysProcAttribute(cmd *exec.Cmd) {
+	// Do nothing
+}
diff --git a/modules/ssh/ssh.go b/modules/ssh/ssh.go
index fe3561cef..a240c0131 100644
--- a/modules/ssh/ssh.go
+++ b/modules/ssh/ssh.go
@@ -102,6 +102,8 @@ func sessionHandler(session ssh.Session) {
 	}
 	defer stdin.Close()
 
+	process.SetSysProcAttribute(cmd)
+
 	wg := &sync.WaitGroup{}
 	wg.Add(2)
 
diff --git a/services/mailer/mailer.go b/services/mailer/mailer.go
index 3ca9b50fc..f4bc2ddc6 100644
--- a/services/mailer/mailer.go
+++ b/services/mailer/mailer.go
@@ -281,6 +281,7 @@ func (s *sendmailSender) Send(from string, to []string, msg io.WriterTo) error {
 	if err != nil {
 		return err
 	}
+	process.SetSysProcAttribute(cmd)
 
 	if err = cmd.Start(); err != nil {
 		_ = pipe.Close()