1 files changed, 56 insertions, 2 deletions
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 6b20a962ecc..d5ac25904da 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -2243,6 +2243,58 @@ check_icu_locale_encoding(int user_enc)
 }
 
 /*
+ * Perform best-effort check that the locale is a valid one. Should be
+ * consistent with pg_locale.c, except that it doesn't need to open the
+ * collator (that will happen during post-bootstrap initialization).
+ */
+static void
+icu_validate_locale(const char *loc_str)
+{
+#ifdef USE_ICU
+	UErrorCode	 status;
+	char		 lang[ULOC_LANG_CAPACITY];
+	bool		 found	 = false;
+
+	/* validate that we can extract the language */
+	status = U_ZERO_ERROR;
+	uloc_getLanguage(loc_str, lang, ULOC_LANG_CAPACITY, &status);
+	if (U_FAILURE(status))
+	{
+		pg_fatal("could not get language from locale \"%s\": %s",
+				 loc_str, u_errorName(status));
+		return;
+	}
+
+	/* check for special language name */
+	if (strcmp(lang, "") == 0 ||
+		strcmp(lang, "root") == 0 || strcmp(lang, "und") == 0 ||
+		strcmp(lang, "c") == 0 || strcmp(lang, "posix") == 0)
+		found = true;
+
+	/* search for matching language within ICU */
+	for (int32_t i = 0; !found && i < uloc_countAvailable(); i++)
+	{
+		const char	*otherloc = uloc_getAvailable(i);
+		char		 otherlang[ULOC_LANG_CAPACITY];
+
+		status = U_ZERO_ERROR;
+		uloc_getLanguage(otherloc, otherlang, ULOC_LANG_CAPACITY, &status);
+		if (U_FAILURE(status))
+			continue;
+
+		if (strcmp(lang, otherlang) == 0)
+			found = true;
+	}
+
+	if (!found)
+		pg_fatal("locale \"%s\" has unknown language \"%s\"",
+				 loc_str, lang);
+#else
+	pg_fatal("ICU is not supported in this build");
+#endif
+}
+
+/*
  * Determine default ICU locale by opening the default collator and reading
  * its locale.
  *
@@ -2344,9 +2396,11 @@ setlocales(void)
 			printf(_("Using default ICU locale \"%s\".\n"), icu_locale);
 		}
 
+		icu_validate_locale(icu_locale);
+
 		/*
-		 * In supported builds, the ICU locale ID will be checked by the
-		 * backend during post-bootstrap initialization.
+		 * In supported builds, the ICU locale ID will be opened during
+		 * post-bootstrap initialization, which will perform extra checks.
 		 */
 #ifndef USE_ICU
 		pg_fatal("ICU is not supported in this build");