tests: replace fread by xfread

With fortification enabled, fread calls return result needs to be checked,
has it gets the __wur macro enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

3 files changed, 41 insertions, 0 deletions

diff --git a/support/Makefile b/support/Makefile
index 130de4a985..1f0f526e06 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -125,6 +125,7 @@ libsupport-routines = \
   xfclose \
   xfopen \
   xfork \
+  xfread \
   xfreopen \
   xftruncate \
   xgetline \
diff --git a/support/xfread.c b/support/xfread.c
new file mode 100644
index 0000000000..948f0c8111
--- /dev/null
+++ b/support/xfread.c
@@ -0,0 +1,39 @@
+/* fread with error checking.
+   Copyright (C) 2023 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/xstdio.h>
+
+#include <support/check.h>
+#include <stdlib.h>
+
+void
+xfread (void *ptr, size_t size, size_t nmemb, FILE *stream)
+{
+  size_t count = 0;
+  char *p = ptr;
+
+  while (count < nmemb)
+    {
+      size_t ret = fread (p, size, nmemb - count, stream);
+      if (ret <= 0 && ferror(stream))
+        FAIL_EXIT1 ("read of %zu bytes failed after %td: %m",
+                    size * nmemb, p - (char *) ptr);
+      count += ret;
+      p += size * ret;
+    }
+}
diff --git a/support/xstdio.h b/support/xstdio.h
index 5410d42579..633c342c82 100644
--- a/support/xstdio.h
+++ b/support/xstdio.h
@@ -27,6 +27,7 @@ __BEGIN_DECLS
 FILE *xfopen (const char *path, const char *mode);
 void xfclose (FILE *);
 FILE *xfreopen (const char *path, const char *mode, FILE *stream);
+void xfread (void *ptr, size_t size, size_t nmemb, FILE *stream);
 
 /* Read a line from FP, using getline.  *BUFFER must be NULL, or a
    heap-allocated pointer of *LENGTH bytes.  Return the number of