[PATCH 2/5] support: Add xgetresgid and xgetresuid

[Florian Weimer]

---
 support/Makefile     |  2 ++
 support/xgetresgid.c | 27 +++++++++++++++++++++++++++
 support/xgetresuid.c | 27 +++++++++++++++++++++++++++
 support/xunistd.h    |  2 ++
 4 files changed, 58 insertions(+)
 create mode 100644 support/xgetresgid.c
 create mode 100644 support/xgetresuid.c

diff --git a/support/Makefile b/support/Makefile
index 93d9735135..e6e3589158 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -145,6 +145,8 @@ libsupport-routines = \
   xftruncate \
   xgetline \
   xgetpeername \
+  xgetresgid \
+  xgetresuid \
   xgetsockname \
   xlisten \
   xlseek \
diff --git a/support/xgetresgid.c b/support/xgetresgid.c
new file mode 100644
index 0000000000..54df2a04f9
--- /dev/null
+++ b/support/xgetresgid.c
@@ -0,0 +1,27 @@
+/* getresgid with error checking.
+   Copyright (C) 2025 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+#include <support/xunistd.h>
+
+void
+xgetresgid (gid_t *real, gid_t *effective, gid_t *saved)
+{
+  if (getresgid (real, effective, saved) != 0)
+    FAIL_EXIT1 ("getresgid: %m");
+}
diff --git a/support/xgetresuid.c b/support/xgetresuid.c
new file mode 100644
index 0000000000..e22fe0923a
--- /dev/null
+++ b/support/xgetresuid.c
@@ -0,0 +1,27 @@
+/* getresuid with error checking.
+   Copyright (C) 2025 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+#include <support/xunistd.h>
+
+void
+xgetresuid (uid_t *real, uid_t *effective, uid_t *saved)
+{
+  if (getresuid (real, effective, saved) != 0)
+    FAIL_EXIT1 ("getresuid: %m");
+}
diff --git a/support/xunistd.h b/support/xunistd.h
index 8f6dd4fd1d..1a5aa58125 100644
--- a/support/xunistd.h
+++ b/support/xunistd.h
@@ -65,6 +65,8 @@ void xchdir (const char *path);
 void xfchmod (int fd, mode_t mode);
 void xchmod (const char *pathname, mode_t mode);
 void xmkfifo (const char *pathname, mode_t mode);
+void xgetresuid (uid_t *, uid_t *, uid_t *);
+void xgetresgid (gid_t *, gid_t *, gid_t *);
 
 /* Equivalent of "mkdir -p".  */
 void xmkdirp (const char *, mode_t);
-- 
2.52.0