[LTP] [PATCH 1/3] syscalls: refactor fork09 using new API

Andrea Cervesato
2026-01-27T12:51:13Z

From: Andrea Cervesato <andrea.cervesato@suse.com>

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
testcases/kernel/syscalls/fork/fork09.c | 218 ++++++++++----------------------
1 file changed, 69 insertions(+), 149 deletions(-)

diff --git a/testcases/kernel/syscalls/fork/fork09.c b/testcases/kernel/syscalls/fork/fork09.c
index 32bad89b35575f1597bed1a44ef3b984bd1db3bd..7ce64b9a1188fe81e1d44d8ea5cb33a2504b8cfd 100644
--- a/testcases/kernel/syscalls/fork/fork09.c
+++ b/testcases/kernel/syscalls/fork/fork09.c
@@ -1,172 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
- * Copyright (c) International Business Machines Corp., 2001
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * NAME
- * fork09.c
- *
- * DESCRIPTION
- * Check that child has access to a full set of files.
- *
- * ALGORITHM
- * Parent opens a maximum number of files
- * Child closes one and attempts to open another, it should be
- * available
- *
- * USAGE
- * fork09
- *
- * HISTORY
- * 07/2001 Ported by Wayne Boyer
- *
- * 10/2008 Suzuki K P <suzuki@in.ibm.com>
- * Fix maximum number of files open logic.
- *
- * RESTRICTIONS
- * None
+ * Copyright (C) 2026 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
*/

-#include <sys/types.h>
-#include <sys/wait.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <errno.h>
-#include <unistd.h> /* for _SC_OPEN_MAX */
-#include "test.h"
-#include "safe_macros.h"
-
-char *TCID = "fork09";
-int TST_TOTAL = 1;
+/*\
+ * Verify that a forked child can close all the files which have been open by
+ * the parent process.
+ */

-static void setup(void);
-static void cleanup(void);
+#include "tst_test.h"
+#include "tst_safe_stdio.h"

-static char filname[40], childfile[40];
-static int first;
-static FILE **fildeses; /* file streams */
-static int mypid, nfiles;
+#define FILE_PREFIX "ltp_file"

-#define OPEN_MAX (sysconf(_SC_OPEN_MAX))
+static FILE **open_files;
+static long file_open_max;

-int main(int ac, char **av)
+static void run(void)
{
- int pid, status, nf;
-
- int lc;
-
- tst_parse_opts(ac, av, NULL, NULL);
-
- setup();
-
- fildeses = malloc((OPEN_MAX + 10) * sizeof(FILE *));
- if (fildeses == NULL)
- tst_brkm(TBROK, cleanup, "malloc failed");
-
- for (lc = 0; TEST_LOOPING(lc); lc++) {
- tst_count = 0;
- mypid = getpid();
-
- tst_resm(TINFO, "OPEN_MAX is %ld", OPEN_MAX);
-
- /* establish first free file */
- sprintf(filname, "fork09.%d", mypid);
- first = SAFE_CREAT(cleanup, filname, 0660);
- close(first);
-
- tst_resm(TINFO, "first file descriptor is %d ", first);
-
- SAFE_UNLINK(cleanup, filname);
-
- /*
- * now open all the files for the test
- */
- for (nfiles = first; nfiles < OPEN_MAX; nfiles++) {
- sprintf(filname, "file%d.%d", nfiles, mypid);
- fildeses[nfiles] = fopen(filname, "a");
- if (fildeses[nfiles] == NULL) {
- /* Did we already reach OPEN_MAX ? */
- if (errno == EMFILE)
- break;
- tst_brkm(TBROK, cleanup, "Parent: cannot open "
- "file %d %s errno = %d", nfiles,
- filname, errno);
- }
-#ifdef DEBUG
- tst_resm(TINFO, "filname: %s", filname);
-#endif
- }
+ FILE *f;
+ long nfiles;
+ long totfiles;
+ char name[PATH_MAX];

- tst_resm(TINFO, "Parent reporting %d files open", nfiles - 1);
-
- pid = fork();
- if (pid == -1)
- tst_brkm(TBROK, cleanup, "Fork failed");
-
- if (pid == 0) { /* child */
- nfiles--;
- if (fclose(fildeses[nfiles]) == -1) {
- tst_resm(TINFO, "Child could not close file "
- "#%d, errno = %d", nfiles, errno);
- exit(1);
- } else {
- sprintf(childfile, "cfile.%d", getpid());
- fildeses[nfiles] = fopen(childfile, "a");
- if (fildeses[nfiles] == NULL) {
- tst_resm(TINFO, "Child could not open "
- "file %s, errno = %d",
- childfile, errno);
- exit(1);
- } else {
- tst_resm(TINFO, "Child opened new "
- "file #%d", nfiles);
- unlink(childfile);
- exit(0);
- }
- }
- } else { /* parent */
- wait(&status);
- if (status >> 8 != 0)
- tst_resm(TFAIL, "test 1 FAILED");
- else
- tst_resm(TPASS, "test 1 PASSED");
- }
+ tst_res(TINFO, "Opening files from parent");
+
+ for (nfiles = 0; nfiles < file_open_max; nfiles++) {
+ memset(name, 0, PATH_MAX);
+ snprintf(name, PATH_MAX, "%s%lu", FILE_PREFIX, nfiles);

- /* clean up things in case we are looping */
- for (nf = first; nf < nfiles; nf++) {
- fclose(fildeses[nf]);
- sprintf(filname, "file%d.%d", nf, mypid);
- unlink(filname);
+ f = fopen(name, "a");
+ if (!f) {
+ if (errno == EMFILE)
+ break;
+
+ tst_brk(TBROK | TERRNO, "fopen() error");
}
+
+ open_files[nfiles] = f;
+ }
+
+ totfiles = nfiles;
+
+ if (!totfiles)
+ tst_brk(TBROK, "Parent couldn't open any file");
+
+ tst_res(TINFO, "Closing %lu files from child", totfiles);
+
+ if (!SAFE_FORK()) {
+ for (nfiles = nfiles - 1; nfiles >= 0; nfiles--)
+ SAFE_FCLOSE(open_files[nfiles]);
+
+ exit(0);
}

- cleanup();
- tst_exit();
+ tst_reap_children();
+
+ tst_res(TPASS, "Child closed all parent's files");
+
+ for (nfiles = 0; nfiles < totfiles; nfiles++) {
+ memset(name, 0, PATH_MAX);
+ snprintf(name, PATH_MAX, "%s%lu", FILE_PREFIX, nfiles);
+
+ SAFE_FCLOSE(open_files[nfiles]);
+ SAFE_UNLINK(name);
+ }
}

static void setup(void)
{
- tst_sig(FORK, DEF_HANDLER, cleanup);
- umask(0);
+ file_open_max = sysconf(_SC_OPEN_MAX);

- TEST_PAUSE;
- tst_tmpdir();
+ open_files = SAFE_MMAP(NULL, sizeof(FILE *) * file_open_max,
+ PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_SHARED,
+ -1, 0);
}

static void cleanup(void)
{
- tst_rmdir();
+ if (open_files)
+ SAFE_MUNMAP(open_files, sizeof(FILE *) * file_open_max);
}
+
+static struct tst_test test = {
+ .test_all = run,
+ .setup = setup,
+ .cleanup = cleanup,
+ .forks_child = 1,
+ .needs_tmpdir = 1,
+};

--
2.51.0