[PATCH nolibc 08/14] selftests/nolibc: skip the chroot_root and link_dir tests when not privileged

["Paul E. McKenney" <paulmck@kernel.org>]

From: Willy Tarreau <w@1wt.eu>

These two tests always fail when the program is started natively as an
unprivileged user, and require the user to carefully check the output
of "make run-user" and ignore them.

Let's add an euid check and condition these two tests to euid==0. Now
the test case stops needlessly reporting failures. E.g.:

  $ make -C tools/testing/selftests/nolibc run-user
  ...
    CC      nolibc-test
  123 test(s) passed.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 772f88bda0f1..6a7c13f0cd61 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -477,6 +477,7 @@ static int test_getpagesize(void)
 int run_syscall(int min, int max)
 {
 	struct stat stat_buf;
+	int euid0;
 	int proc;
 	int test;
 	int tmp;
@@ -486,6 +487,9 @@ int run_syscall(int min, int max)
 	/* <proc> indicates whether or not /proc is mounted */
 	proc = stat("/proc", &stat_buf) == 0;
 
+	/* this will be used to skip certain tests that can't be run unprivileged */
+	euid0 = geteuid() == 0;
+
 	for (test = min; test >= 0 && test <= max; test++) {
 		int llen = 0; // line length
 
@@ -511,7 +515,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(chmod_net);         EXPECT_SYSZR(proc, chmod("/proc/self/net", 0555)); break;
 		CASE_TEST(chmod_self);        EXPECT_SYSER(proc, chmod("/proc/self", 0555), -1, EPERM); break;
 		CASE_TEST(chown_self);        EXPECT_SYSER(proc, chown("/proc/self", 0, 0), -1, EPERM); break;
-		CASE_TEST(chroot_root);       EXPECT_SYSZR(1, chroot("/")); break;
+		CASE_TEST(chroot_root);       EXPECT_SYSZR(euid0, chroot("/")); break;
 		CASE_TEST(chroot_blah);       EXPECT_SYSER(1, chroot("/proc/self/blah"), -1, ENOENT); break;
 		CASE_TEST(chroot_exe);        EXPECT_SYSER(proc, chroot("/proc/self/exe"), -1, ENOTDIR); break;
 		CASE_TEST(close_m1);          EXPECT_SYSER(1, close(-1), -1, EBADF); break;
@@ -536,7 +540,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
 		CASE_TEST(link_root1);        EXPECT_SYSER(1, link("/", "/"), -1, EEXIST); break;
 		CASE_TEST(link_blah);         EXPECT_SYSER(1, link("/proc/self/blah", "/blah"), -1, ENOENT); break;
-		CASE_TEST(link_dir);          EXPECT_SYSER(1, link("/", "/blah"), -1, EPERM); break;
+		CASE_TEST(link_dir);          EXPECT_SYSER(euid0, link("/", "/blah"), -1, EPERM); break;
 		CASE_TEST(link_cross);        EXPECT_SYSER(proc, link("/proc/self/net", "/blah"), -1, EXDEV); break;
 		CASE_TEST(lseek_m1);          EXPECT_SYSER(1, lseek(-1, 0, SEEK_SET), -1, EBADF); break;
 		CASE_TEST(lseek_0);           EXPECT_SYSER(1, lseek(0, 0, SEEK_SET), -1, ESPIPE); break;
-- 
2.40.0.rc2