chore: vendor

vendor/github.com/docker/go-connections/sockets/unix_socket.go

@@ -0,0 +1,126 @@
+//go:build !windows
+
+/*
+Package sockets is a simple unix domain socket wrapper.
+
+# Usage
+
+For example:
+
+	import(
+		"fmt"
+		"net"
+		"os"
+		"github.com/docker/go-connections/sockets"
+	)
+
+	func main() {
+		l, err := sockets.NewUnixSocketWithOpts("/path/to/sockets",
+			sockets.WithChown(0,0),sockets.WithChmod(0660))
+		if err != nil {
+			panic(err)
+		}
+		echoStr := "hello"
+
+		go func() {
+			for {
+				conn, err := l.Accept()
+				if err != nil {
+					return
+				}
+				conn.Write([]byte(echoStr))
+				conn.Close()
+			}
+		}()
+
+		conn, err := net.Dial("unix", path)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		buf := make([]byte, 5)
+		if _, err := conn.Read(buf); err != nil {
+			panic(err)
+		} else if string(buf) != echoStr {
+			panic(fmt.Errorf("msg may lost"))
+		}
+	}
+*/
+package sockets
+
+import (
+	"net"
+	"os"
+	"syscall"
+)
+
+// SockOption sets up socket file's creating option
+type SockOption func(string) error
+
+// WithChown modifies the socket file's uid and gid
+func WithChown(uid, gid int) SockOption {
+	return func(path string) error {
+		if err := os.Chown(path, uid, gid); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+// WithChmod modifies socket file's access mode.
+func WithChmod(mask os.FileMode) SockOption {
+	return func(path string) error {
+		if err := os.Chmod(path, mask); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+// NewUnixSocketWithOpts creates a unix socket with the specified options.
+// By default, socket permissions are 0000 (i.e.: no access for anyone); pass
+// WithChmod() and WithChown() to set the desired ownership and permissions.
+//
+// This function temporarily changes the system's "umask" to 0777 to work around
+// a race condition between creating the socket and setting its permissions. While
+// this should only be for a short duration, it may affect other processes that
+// create files/directories during that period.
+func NewUnixSocketWithOpts(path string, opts ...SockOption) (net.Listener, error) {
+	if err := syscall.Unlink(path); err != nil && !os.IsNotExist(err) {
+		return nil, err
+	}
+
+	// net.Listen does not allow for permissions to be set. As a result, when
+	// specifying custom permissions ("WithChmod()"), there is a short time
+	// between creating the socket and applying the permissions, during which
+	// the socket permissions are Less restrictive than desired.
+	//
+	// To work around this limitation of net.Listen(), we temporarily set the
+	// umask to 0777, which forces the socket to be created with 000 permissions
+	// (i.e.: no access for anyone). After that, WithChmod() must be used to set
+	// the desired permissions.
+	//
+	// We don't use "defer" here, to reset the umask to its original value as soon
+	// as possible. Ideally we'd be able to detect if WithChmod() was passed as
+	// an option, and skip changing umask if default permissions are used.
+	origUmask := syscall.Umask(0o777)
+	l, err := net.Listen("unix", path)
+	syscall.Umask(origUmask)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, op := range opts {
+		if err := op(path); err != nil {
+			_ = l.Close()
+			return nil, err
+		}
+	}
+
+	return l, nil
+}
+
+// NewUnixSocket creates a unix socket with the specified path and group.
+func NewUnixSocket(path string, gid int) (net.Listener, error) {
+	return NewUnixSocketWithOpts(path, WithChown(0, gid), WithChmod(0o660))
+}