Better error reporting if the link target is too long

This situation won't set errno, so using %m will give an incorrect
error message.

diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 4453e818c0074fbfc80cfd954202f6bedab5e09a..478f203273fac7ed677e666148a4c5259717022f 100644 (file)
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -287,9 +287,12 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
         */
        snprintf(sourcepath, sizeof(sourcepath), "pg_tblspc/%u", tablespaceOid);
        rllen =readlink(sourcepath, targetpath, sizeof(targetpath));
-       if (rllen < 0 || rllen >= sizeof(targetpath))
+       if (rllen < 0)
                ereport(ERROR,
                                (errmsg("could not read symbolic link \"%s\": %m", sourcepath)));
+       else if (rllen >= sizeof(targetpath))
+               ereport(ERROR,
+                               (errmsg("symbolic link \"%s\" target is too long", sourcepath)));
        targetpath[rllen] = '\0';
 
        PG_RETURN_TEXT_P(cstring_to_text(targetpath));