--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2014-05-14  Guilherme de Almeida Suckevicz  <guito.linux@gmail.com>
+
+	getlogin-tests: avoid false failure under sudo/ssh etc.
+	* modules/getlogin-tests (configure.ac): Check for ttyname().
+	* tests/test-getlogin.c (main): Don't depend on environment variables
+	to correlate with getlogin(), since sudo and ssh etc. can tamper
+	with the LOGNAME and USER env vars.  Instead lookup the name from
+	the uid associated with the stdin tty.
+
 2014-05-11  Paul Eggert  <eggert@cs.ucla.edu>
 
 	mbsstr, quotearg, xstrtol: pacify IRIX 6.5 cc

--- a/modules/getlogin-tests
+++ b/modules/getlogin-tests
@@ -6,6 +6,7 @@
 Depends-on:
 
 configure.ac:
+AC_CHECK_FUNCS_ONCE([ttyname])
 
 Makefile.am:
 TESTS += test-getlogin

--- a/tests/test-getlogin.c
+++ b/tests/test-getlogin.c
@@ -27,6 +27,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+#include <pwd.h>
+
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #include "macros.h"
 
@@ -62,11 +67,32 @@
 #if !((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__)
   /* Unix platform */
   {
-    const char *name = getenv ("LOGNAME");
-    if (name == NULL || name[0] == '\0')
-      name = getenv ("USER");
-    if (name != NULL && name[0] != '\0')
-      ASSERT (strcmp (buf, name) == 0);
+# if HAVE_TTYNAME
+    const char *tty;
+    struct stat stat_buf;
+    struct passwd *pwd;
+
+    tty = ttyname (STDIN_FILENO);
+    if (tty == NULL)
+      {
+         ASSERT (errno == ENOTTY);
+
+         fprintf (stderr, "Skipping test: stdin is not a tty.\n");
+         return 77;
+      }
+
+    ASSERT (stat (tty, &stat_buf) == 0);
+
+    pwd = getpwuid (stat_buf.st_uid);
+    if (! pwd)
+      {
+         fprintf (stderr, "Skipping test: no name found for uid %d\n",
+                  stat_buf.st_uid);
+         return 77;
+      }
+
+    ASSERT (strcmp (pwd->pw_name, buf) == 0);
+# endif
   }
 #endif
 #if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__