libio: Use stdin consistently for input functions [BZ #24153]

The internal _IO_stdin_ variable is not updated when the application
assigns to stdin, which is a GNU extension.

1 files changed, 114 insertions, 0 deletions

diff --git a/libio/tst-bz24153.c b/libio/tst-bz24153.c
new file mode 100644
index 0000000..85ad141
--- /dev/null
+++ b/libio/tst-bz24153.c
@@ -0,0 +1,114 @@
+/* Test that assigning to stdin redirects input (bug 24153).
+   Copyright (C) 2019 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/>.  */
+
+/* Prevent getchar -> getc inline expansion.  */
+#define __NO_INLINE__
+#pragma GCC optimize ("O0")
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/temp_file.h>
+#include <support/xstdio.h>
+#include <support/xunistd.h>
+#include <wchar.h>
+
+static int
+call_vscanf (const char *format, ...)
+{
+  va_list ap;
+  va_start (ap, format);
+  int ret = vscanf (format, ap);
+  va_end (ap);
+  return ret;
+}
+
+static int
+call_vwscanf (const wchar_t *format, ...)
+{
+  va_list ap;
+  va_start (ap, format);
+  int ret = vwscanf (format, ap);
+  va_end (ap);
+  return ret;
+}
+
+static void
+narrow (const char *path)
+{
+  FILE *old_stdin = stdin;
+  stdin = xfopen (path, "r");
+
+  TEST_COMPARE (getchar (), 'a');
+  TEST_COMPARE (getchar_unlocked (), 'b');
+  char ch = 1;
+  TEST_COMPARE (scanf ("%c", &ch), 1);
+  TEST_COMPARE (ch, 'c');
+  TEST_COMPARE (call_vscanf ("%c", &ch), 1);
+  TEST_COMPARE (ch, 'd');
+  char buf[8];
+  memset (buf, 'X', sizeof (buf));
+
+  /* Legacy interface.  */
+  extern char *gets (char *);
+  TEST_VERIFY (gets (buf) == buf);
+  TEST_COMPARE_BLOB (buf, sizeof (buf), "ef\0XXXXX", sizeof (buf));
+
+  fclose (stdin);
+  stdin = old_stdin;
+}
+
+static void
+wide (const char *path)
+{
+  FILE *old_stdin = stdin;
+  stdin = xfopen (path, "r");
+
+  TEST_COMPARE (getwchar (), L'a');
+  TEST_COMPARE (getwchar_unlocked (), L'b');
+  wchar_t ch = 1;
+  TEST_COMPARE (wscanf (L"%c", &ch), 1);
+  TEST_COMPARE (ch, L'c');
+  TEST_COMPARE (call_vwscanf (L"%c", &ch), 1);
+  TEST_COMPARE (ch, L'd');
+
+  fclose (stdin);
+  stdin = old_stdin;
+}
+
+static int
+do_test (void)
+{
+  char *path;
+  {
+    int fd = create_temp_file ("tst-bz24153-", &path);
+    TEST_VERIFY_EXIT (fd >= 0);
+    xwrite (fd, "abcdef", strlen ("abcdef"));
+    xclose (fd);
+  }
+
+  narrow (path);
+  wide (path);
+
+  free (path);
+  return 0;
+}
+
+#include <support/test-driver.c>