[COMMITTED 2.31 2/7] Add xchdir to libsupport.

[Aurelien Jarno <aurelien@aurel32.net>]

From: Alexandra Hájková <ahajkova@redhat.com>

(cherry picked from commit a7e9dbb7742954814643a8562dcad09abb0b0e5d)
---
 support/Makefile  |  1 +
 support/xchdir.c  | 28 ++++++++++++++++++++++++++++
 support/xunistd.h |  1 +
 3 files changed, 30 insertions(+)
 create mode 100644 support/xchdir.c

diff --git a/support/Makefile b/support/Makefile
index 3325feb790..a40a2f5bca 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -83,6 +83,7 @@ libsupport-routines = \
   xasprintf \
   xbind \
   xcalloc \
+  xchdir \
   xchroot \
   xclock_gettime \
   xclose \
diff --git a/support/xchdir.c b/support/xchdir.c
new file mode 100644
index 0000000000..beb4feff72
--- /dev/null
+++ b/support/xchdir.c
@@ -0,0 +1,28 @@
+/* chdir with error checking.
+   Copyright (C) 2020 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 <support/check.h>
+#include <support/xunistd.h>
+#include <unistd.h>
+
+void
+xchdir (const char *path)
+{
+  if (chdir (path) != 0)
+    FAIL_EXIT1 ("chdir (\"%s\"): %m", path);
+}
diff --git a/support/xunistd.h b/support/xunistd.h
index 96f498f2e5..43799d92c5 100644
--- a/support/xunistd.h
+++ b/support/xunistd.h
@@ -44,6 +44,7 @@ long xsysconf (int name);
 long long xlseek (int fd, long long offset, int whence);
 void xftruncate (int fd, long long length);
 void xsymlink (const char *target, const char *linkpath);
+void xchdir (const char *path);
 
 /* Equivalent of "mkdir -p".  */
 void xmkdirp (const char *, mode_t);
-- 
2.35.1