getcwd tests: Avoid test failure when running under QEMU user-mode.

* modules/getcwd-tests (Files): Add qemu.h.
(Depends-on): Add stdbool.
* tests/test-getcwd.c: Include qemu.h.
(test_long_name): Skip this test when running under QEMU user-mode.
(main): Consider return code 77 from test_long_name.

3 files changed, 23 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index ee933c9efa..88a396e09e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2021-08-29  Bruno Haible  <bruno@clisp.org>
+
+	getcwd tests: Avoid test failure when running under QEMU user-mode.
+	* modules/getcwd-tests (Files): Add qemu.h.
+	(Depends-on): Add stdbool.
+	* tests/test-getcwd.c: Include qemu.h.
+	(test_long_name): Skip this test when running under QEMU user-mode.
+	(main): Consider return code 77 from test_long_name.
+
 2021-08-29  Paul Eggert  <eggert@cs.ucla.edu>
 
 	base32, base64: treat negative sizes as overflows
diff --git a/modules/getcwd-tests b/modules/getcwd-tests
index e5a7bd78b1..c842c77115 100644
--- a/modules/getcwd-tests
+++ b/modules/getcwd-tests
@@ -1,12 +1,14 @@
 Files:
-tests/test-getcwd.c
 tests/test-getcwd.sh
+tests/test-getcwd.c
+tests/qemu.h
 
 Depends-on:
 errno
 fcntl-h
 getcwd-lgpl
 pathmax
+stdbool
 sys_stat
 test-framework-sh
 
diff --git a/tests/test-getcwd.c b/tests/test-getcwd.c
index 061c69eb12..051d4f26a0 100644
--- a/tests/test-getcwd.c
+++ b/tests/test-getcwd.c
@@ -27,6 +27,7 @@
 #include <sys/stat.h>
 
 #include "pathmax.h"
+#include "qemu.h"
 #include "macros.h"
 
 #if !(HAVE_GETPAGESIZE || defined getpagesize)
@@ -138,6 +139,13 @@ test_long_name (void)
      this should be done in a compile test.  */
   return 0;
 #else
+  /* For a process running under QEMU user-mode, the "/" directory is not
+     really the root directory, but the value of the QEMU_LD_PREFIX environment
+     variable or of the -L command-line option.  This causes the logic from
+     glibc/sysdeps/posix/getcwd.c to fail.  In this case, skip the test.  */
+  if (is_running_under_qemu_user ())
+    return 77;
+
   char buf[PATH_MAX * (DIR_NAME_SIZE / DOTDOTSLASH_LEN + 1)
            + DIR_NAME_SIZE + BUF_SLOP];
   char *cwd = getcwd (buf, PATH_MAX);
@@ -256,5 +264,7 @@ test_long_name (void)
 int
 main (int argc, char **argv)
 {
-  return test_abort_bug () * 10 + test_long_name ();
+  int err1 = test_abort_bug ();
+  int err2 = test_long_name ();
+  return err1 * 10 + (err1 != 0 && err2 == 77 ? 0 : err2);
 }