1 files changed, 80 insertions, 0 deletions
diff --git a/src/port/getpeereid.c b/src/port/getpeereid.c
new file mode 100644
index 0000000..d6aa755
--- /dev/null
+++ b/src/port/getpeereid.c
@@ -0,0 +1,80 @@
+/*-------------------------------------------------------------------------
+ *
+ * getpeereid.c
+ *		get peer userid for UNIX-domain socket connection
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/port/getpeereid.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h>
+#endif
+#ifdef HAVE_UCRED_H
+#include <ucred.h>
+#endif
+#ifdef HAVE_SYS_UCRED_H
+#include <sys/ucred.h>
+#endif
+
+
+/*
+ * BSD-style getpeereid() for platforms that lack it.
+ */
+int
+getpeereid(int sock, uid_t *uid, gid_t *gid)
+{
+#if defined(SO_PEERCRED)
+	/* Linux: use getsockopt(SO_PEERCRED) */
+	struct ucred peercred;
+	ACCEPT_TYPE_ARG3 so_len = sizeof(peercred);
+
+	if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
+		so_len != sizeof(peercred))
+		return -1;
+	*uid = peercred.uid;
+	*gid = peercred.gid;
+	return 0;
+#elif defined(LOCAL_PEERCRED)
+	/* Debian with FreeBSD kernel: use getsockopt(LOCAL_PEERCRED) */
+	struct xucred peercred;
+	ACCEPT_TYPE_ARG3 so_len = sizeof(peercred);
+
+	if (getsockopt(sock, 0, LOCAL_PEERCRED, &peercred, &so_len) != 0 ||
+		so_len != sizeof(peercred) ||
+		peercred.cr_version != XUCRED_VERSION)
+		return -1;
+	*uid = peercred.cr_uid;
+	*gid = peercred.cr_gid;
+	return 0;
+#elif defined(HAVE_GETPEERUCRED)
+	/* Solaris: use getpeerucred() */
+	ucred_t    *ucred;
+
+	ucred = NULL;				/* must be initialized to NULL */
+	if (getpeerucred(sock, &ucred) == -1)
+		return -1;
+
+	*uid = ucred_geteuid(ucred);
+	*gid = ucred_getegid(ucred);
+	ucred_free(ucred);
+
+	if (*uid == (uid_t) (-1) || *gid == (gid_t) (-1))
+		return -1;
+	return 0;
+#else
+	/* No implementation available on this platform */
+	errno = ENOSYS;
+	return -1;
+#endif
+}