Allow to drop privileges my changing uid/gid

This feature is only available for unix OSes and allow to setuid and
setgid after creating a listening socket.

1 files changed, 25 insertions, 0 deletions

diff --git a/setuid_unix.go b/setuid_unix.go
new file mode 100644
index 0000000..be2db7b
--- /dev/null
+++ b/setuid_unix.go
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"errors"
+	"syscall"
+)
+
+func setUidGid(syscallID uint, uidgid uint16) error {
+	if uidgid == 0 {
+		return nil
+	}
+	_, _, errno := syscall.Syscall(uintptr(syscallID), uintptr(uidgid), 0, 0)
+	if errno != 0 {
+		return errors.New(errno.Error())
+	}
+	return nil
+}
+
+func setUID(uid uint16) error {
+	return setUidGid(syscall.SYS_SETUID, uid)
+}
+
+func setGID(gid uint16) error {
+	return setUidGid(syscall.SYS_SETGID, gid)
+}