1 files changed, 87 insertions, 0 deletions
diff --git a/src/common/username.c b/src/common/username.c
new file mode 100644
index 0000000..669b8ab
--- /dev/null
+++ b/src/common/username.c
@@ -0,0 +1,87 @@
+/*-------------------------------------------------------------------------
+ *
+ * username.c
+ *	  get user name
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/common/username.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef FRONTEND
+#include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
+
+#include <pwd.h>
+#include <unistd.h>
+
+#include "common/username.h"
+
+/*
+ * Returns the current user name in a static buffer
+ * On error, returns NULL and sets *errstr to point to a palloc'd message
+ */
+const char *
+get_user_name(char **errstr)
+{
+#ifndef WIN32
+	struct passwd *pw;
+	uid_t		user_id = geteuid();
+
+	*errstr = NULL;
+
+	errno = 0;					/* clear errno before call */
+	pw = getpwuid(user_id);
+	if (!pw)
+	{
+		*errstr = psprintf(_("could not look up effective user ID %ld: %s"),
+						   (long) user_id,
+						   errno ? strerror(errno) : _("user does not exist"));
+		return NULL;
+	}
+
+	return pw->pw_name;
+#else
+	/* Microsoft recommends buffer size of UNLEN+1, where UNLEN = 256 */
+	/* "static" variable remains after function exit */
+	static char username[256 + 1];
+	DWORD		len = sizeof(username);
+
+	*errstr = NULL;
+
+	if (!GetUserName(username, &len))
+	{
+		*errstr = psprintf(_("user name lookup failure: error code %lu"),
+						   GetLastError());
+		return NULL;
+	}
+
+	return username;
+#endif
+}
+
+
+/*
+ * Returns the current user name in a static buffer or exits
+ */
+const char *
+get_user_name_or_exit(const char *progname)
+{
+	const char *user_name;
+	char	   *errstr;
+
+	user_name = get_user_name(&errstr);
+
+	if (!user_name)
+	{
+		fprintf(stderr, "%s: %s\n", progname, errstr);
+		exit(1);
+	}
+	return user_name;
+}