@@ -94,6 +94,7 @@ tests = \
tst-eof \
tst-ext \
tst-ext2 \
+ tst-fclose \
tst-fgetc-after-eof \
tst-fgetwc \
tst-fgetws \
@@ -92,10 +92,10 @@ struct _IO_FILE_complete
struct _IO_wide_data *_wide_data;
struct _IO_FILE *_freeres_list;
void *_freeres_buf;
- size_t __pad5;
+ struct _IO_FILE **_prevchain;
int _mode;
/* Make sure we don't get into trouble again. */
- char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
+ char _unused2[15 * sizeof (int) - 5 * sizeof (void *)];
};
/* These macros are used by bits/stdio.h and internal headers. */
@@ -48,6 +48,19 @@ flush_cleanup (void *not_used)
}
#endif
+/* Fields in struct _IO_FILE after the _lock field are internal to
+ glibc and opaque to applications. We can change them as long as
+ the size of struct _IO_FILE is unchanged, which is checked as the
+ part of glibc ABI with sizes of _IO_2_1_stdin_, _IO_2_1_stdout_
+ and _IO_2_1_stderr_.
+
+ NB: When _IO_vtable_offset (fp) == 0, copy relocation will cover the
+ whole struct _IO_FILE. Otherwise, only fields up to the _lock field
+ will be copied. */
+_Static_assert (offsetof (struct _IO_FILE, _prevchain)
+ > offsetof (struct _IO_FILE, _lock),
+ "offset of _prevchain > offset of _lock");
+
void
_IO_un_link (struct _IO_FILE_plus *fp)
{
@@ -62,6 +75,14 @@ _IO_un_link (struct _IO_FILE_plus *fp)
#endif
if (_IO_list_all == NULL)
;
+ else if (_IO_vtable_offset ((FILE *) fp) == 0)
+ {
+ FILE **pr = fp->file._prevchain;
+ FILE *nx = fp->file._chain;
+ *pr = nx;
+ if (nx != NULL)
+ nx->_prevchain = pr;
+ }
else if (fp == _IO_list_all)
_IO_list_all = (struct _IO_FILE_plus *) _IO_list_all->file._chain;
else
@@ -95,6 +116,11 @@ _IO_link_in (struct _IO_FILE_plus *fp)
_IO_flockfile ((FILE *) fp);
#endif
fp->file._chain = (FILE *) _IO_list_all;
+ if (_IO_vtable_offset ((FILE *) fp) == 0)
+ {
+ fp->file._prevchain = (FILE **) &_IO_list_all;
+ _IO_list_all->file._prevchain = &fp->file._chain;
+ }
_IO_list_all = fp;
#ifdef _IO_MTSAFE_IO
_IO_funlockfile ((FILE *) fp);
@@ -54,4 +54,19 @@ DEF_STDFILE(_IO_2_1_stdout_, 1, &_IO_2_1_stdin_, _IO_NO_READS);
DEF_STDFILE(_IO_2_1_stderr_, 2, &_IO_2_1_stdout_, _IO_NO_READS+_IO_UNBUFFERED);
struct _IO_FILE_plus *_IO_list_all = &_IO_2_1_stderr_;
+
+/* Finish the double-linking for stdfiles as static initialization
+ cannot. */
+
+__THROW __attribute__ ((constructor))
+static void
+_IO_stdfiles_init (void)
+{
+ struct _IO_FILE **f;
+ for (f = (struct _IO_FILE **) &_IO_list_all;
+ *f != NULL;
+ f = &(*f)->_chain)
+ (*f)->_prevchain = f;
+}
+
libc_hidden_data_def (_IO_list_all)
new file mode 100644
@@ -0,0 +1,56 @@
+/* Verify fclose performance with many opened files.
+ Copyright (C) 2024 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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <support/test-driver.h>
+
+#define N 2000000
+#define M 100
+
+static int
+do_test (void)
+{
+ FILE *ff, *keep[M];
+ int i;
+
+ fprintf (stderr, "Preparing %d FILEs ...\n", N);
+ fflush (stderr);
+ for (i = 0; i < N; i++)
+ {
+ ff = fdopen (STDIN_FILENO, "r");
+ if (!ff)
+ {
+ fprintf (stderr, "### failed to fdopen: %m\n");
+ return EXIT_FAILURE;
+ }
+ if (i < M)
+ keep[i] = ff;
+ }
+ fprintf (stderr, "Now fclosing %d FILEs ...", M);
+ fflush (stderr);
+ for (i = 0; i < M; i++)
+ fclose (keep[i]);
+ fprintf (stderr, "DONE\n");
+ fflush (stderr);
+ return EXIT_SUCCESS;
+}
+
+#define TIMEOUT 2
+#include <support/test-driver.c>