1 files changed, 89 insertions, 0 deletions
diff --git a/src/port/user.c b/src/port/user.c
new file mode 100644
index 00000000000..d278684fe29
--- /dev/null
+++ b/src/port/user.c
@@ -0,0 +1,89 @@
+/*-------------------------------------------------------------------------
+ *
+ * user.c
+ *
+ *		  Wrapper functions for user and home directory lookup.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ *
+ * src/port/user.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+#include <pwd.h>
+
+#ifndef WIN32
+
+/*
+ * pg_get_user_name - get the name of the user with the given ID
+ *
+ * On success, the user name is returned into the buffer (of size buflen),
+ * and "true" is returned.  On failure, a localized error message is
+ * returned into the buffer, and "false" is returned.
+ */
+bool
+pg_get_user_name(uid_t user_id, char *buffer, size_t buflen)
+{
+	char		pwdbuf[BUFSIZ];
+	struct passwd pwdstr;
+	struct passwd *pw = NULL;
+	int			pwerr;
+
+	pwerr = getpwuid_r(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
+	if (pw != NULL)
+	{
+		strlcpy(buffer, pw->pw_name, buflen);
+		return true;
+	}
+	if (pwerr != 0)
+		snprintf(buffer, buflen,
+				 _("could not look up local user ID %d: %s"),
+				 (int) user_id,
+				 strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
+	else
+		snprintf(buffer, buflen,
+				 _("local user with ID %d does not exist"),
+				 (int) user_id);
+	return false;
+}
+
+/*
+ * pg_get_user_home_dir - get the home directory of the user with the given ID
+ *
+ * On success, the directory path is returned into the buffer (of size buflen),
+ * and "true" is returned.  On failure, a localized error message is
+ * returned into the buffer, and "false" is returned.
+ *
+ * Note that this does not incorporate the common behavior of checking
+ * $HOME first, since it's independent of which user_id is queried.
+ */
+bool
+pg_get_user_home_dir(uid_t user_id, char *buffer, size_t buflen)
+{
+	char		pwdbuf[BUFSIZ];
+	struct passwd pwdstr;
+	struct passwd *pw = NULL;
+	int			pwerr;
+
+	pwerr = getpwuid_r(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
+	if (pw != NULL)
+	{
+		strlcpy(buffer, pw->pw_dir, buflen);
+		return true;
+	}
+	if (pwerr != 0)
+		snprintf(buffer, buflen,
+				 _("could not look up local user ID %d: %s"),
+				 (int) user_id,
+				 strerror_r(pwerr, pwdbuf, sizeof(pwdbuf)));
+	else
+		snprintf(buffer, buflen,
+				 _("local user with ID %d does not exist"),
+				 (int) user_id);
+	return false;
+}
+
+#endif							/* !WIN32 */