[PATCH] getrusage: Add smoke test for getrusage

[Ondrej Marek]

Add smoke test verifying that getrusage returns non-negative user time and fails with invalid who value.

Co-authored-by: Frantisek Cech <fr.cech@proton.me>
Signed-off-by: Ondrej Marek <ondrejm4rek@gmail.com>
---
 resource/Makefile        |  1 +
 resource/tst-getrusage.c | 87 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 resource/tst-getrusage.c

diff --git a/resource/Makefile b/resource/Makefile
index 589b73f44f..dac48434dd 100644
--- a/resource/Makefile
+++ b/resource/Makefile
@@ -28,6 +28,7 @@ routines := getrlimit setrlimit getrlimit64 setrlimit64 getrusage ulimit      \
 tests := \
   bug-ulimit1 \
   tst-getrlimit \
+  tst-getrusage \
 # tests
 
 
diff --git a/resource/tst-getrusage.c b/resource/tst-getrusage.c
new file mode 100644
index 0000000000..3ef2b15ddb
--- /dev/null
+++ b/resource/tst-getrusage.c
@@ -0,0 +1,87 @@
+/* Test of the getrusage function.
+   Copyright (C) 2005-2026 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <sys/resource.h>
+
+static int
+test_getrusage (int who)
+{
+  struct rusage before_usage = { 0 };
+  struct rusage after_usage = { 0 };
+
+  int ret_val = getrusage (who, &before_usage);
+  if (ret_val != 0)
+    {
+      puts ("Valid who should return 0\n");
+      return 1;
+    }
+  if (before_usage.ru_utime.tv_sec < 0)
+    {
+      puts ("Should return non-negative user time\n");
+      return 1;
+    }
+
+  /* Simulate some work */
+  for (int i = 0; i < 10000000; i++) {}
+
+  int ret_val2 = getrusage (who, &after_usage);
+  if (ret_val2 != 0)
+    {
+      puts ("Valid who should return 0\n");
+      return 1;
+    }
+  if (before_usage.ru_utime.tv_sec > after_usage.ru_utime.tv_sec)
+    {
+      puts ("User time after work should be same or greater than before work\n");
+      return 1;
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  int whos[] = { RUSAGE_SELF, RUSAGE_CHILDREN, RUSAGE_THREAD };
+  for (int i = 0; i < sizeof (whos) / sizeof (int); i++)
+    {
+      int who = whos[i];
+      int retval = test_getrusage (who);
+      if (retval != 0)
+        {
+          return 1;
+        }
+    }
+
+  struct rusage usage_struct = { 0 };
+  int invalid_who = 999;
+  int ret_val3 = getrusage (invalid_who, &usage_struct);
+  if (ret_val3 != -1)
+    {
+      puts ("Invalid who should return -1\n");
+      return 1;
+    }
+
+  puts ("Everything OK\n");
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
-- 
2.47.3