From c62f3e8b39e7d1ff3d46cc4d3d599b2450b3c097 Mon Sep 17 00:00:00 2001
From: Grégoire Duchêne <gduchene@awhk.org>
Date: Sun, 27 Jun 2021 19:31:23 +0100
Subject: First draft

---
 socket_linux.go | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 socket_linux.go

(limited to 'socket_linux.go')

diff --git a/socket_linux.go b/socket_linux.go
new file mode 100644
index 0000000..8360318
--- /dev/null
+++ b/socket_linux.go
@@ -0,0 +1,59 @@
+// +build linux,!nosystemd
+
+package gosdd
+
+// #cgo LDFLAGS: -lsystemd
+// #include <stdlib.h>
+// #include <string.h>
+// #include <systemd/sd-daemon.h>
+import "C"
+
+import (
+	"fmt"
+	"os"
+	"unsafe"
+)
+
+func sdListenFDs(unsetenv bool) ([]*os.File, error) {
+	i := C.int(0)
+	if unsetenv {
+		i = C.int(1)
+	}
+	c := C.sd_listen_fds(i)
+	if c < 0 {
+		return nil, fmt.Errorf("sd_listen_fds: %s", C.GoString(C.strerror(-c)))
+	}
+	if c == 0 {
+		return nil, nil
+	}
+	fds := make([]*os.File, 0, c)
+	for fd := uintptr(C.SD_LISTEN_FDS_START); fd < uintptr(C.SD_LISTEN_FDS_START+c); fd++ {
+		fds = append(fds, os.NewFile(fd, ""))
+	}
+	return fds, nil
+}
+
+func sdListenFDsWithNames(unsetenv bool) (map[string]*os.File, error) {
+	i := C.int(0)
+	if unsetenv {
+		i = C.int(1)
+	}
+	var arr **C.char
+	c := C.sd_listen_fds_with_names(i, &arr)
+	if c < 0 {
+		return nil, fmt.Errorf("sd_listen_fds_with_names: %s", C.GoString(C.strerror(-c)))
+	}
+	if c == 0 {
+		return nil, nil
+	}
+	// See https://github.com/golang/go/wiki/cgo#turning-c-arrays-into-go-slices.
+	names := (*[1 << 28]*C.char)(unsafe.Pointer(arr))[:c:c]
+	fds := make(map[string]*os.File)
+	for fd := uintptr(C.SD_LISTEN_FDS_START); fd < uintptr(C.SD_LISTEN_FDS_START+c); fd++ {
+		name := C.GoString(names[int(fd-C.SD_LISTEN_FDS_START)])
+		fds[name] = os.NewFile(fd, name)
+		C.free(unsafe.Pointer(names[int(fd-C.SD_LISTEN_FDS_START)]))
+	}
+	C.free(unsafe.Pointer(arr))
+	return fds, nil
+}
-- 
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