[LTP] [PATCH v2] Refactor pidns16 test using new LTP API
Richard Palethorpe
rpalethorpe@suse.de
Tue Nov 1 12:06:22 CET 2022
Hello,
Andrea Cervesato via ltp <ltp@lists.linux.it> writes:
> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
> ---
> testcases/kernel/containers/pidns/pidns16.c | 197 +++++++-------------
> 1 file changed, 68 insertions(+), 129 deletions(-)
>
> diff --git a/testcases/kernel/containers/pidns/pidns16.c b/testcases/kernel/containers/pidns/pidns16.c
> index 2ee61065a..d11e8eaa1 100644
> --- a/testcases/kernel/containers/pidns/pidns16.c
> +++ b/testcases/kernel/containers/pidns/pidns16.c
> @@ -1,157 +1,96 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> /*
> -* Copyright (c) International Business Machines Corp., 2007
> -* 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
> -*
> -***************************************************************************
> -
> -* * Test Assertion.
> -* *----------------
> -* * kill -USR1 container_init
> -* * - from the parent process and also inside a container
> -* * - Where init has defined a custom handler for USR1
> -* * - Should call the handler and
> -* * - Verify whether the signal handler is called from the proper process.
> -* *
> -* * Description:
> -* * Create PID namespace container.
> -* * Container init defines the handler for SIGUSR1 and waits indefinetly.
> -* * Parent sends SIGUSR1 to container init.
> -* * The signal handler is handled and the cont-init resumes normally.
> -* * From the container, again the signal SIGUSR1 is sent.
> -* * In the sig-handler check if it's invoked from correct pid(parent/container)
> -* * If cont-init wakes up properly -
> -* * it will return expected value at exit which is verified at the end.
> -* *
> -* * History:
> -* * DATE NAME DESCRIPTION
> -* * 04/11/08 Veerendra C <vechandr@in.ibm.com> Verifying cont init kill -USR1
> -*
> -*******************************************************************************/
> -#include "config.h"
> + * Copyright (c) International Business Machines Corp., 2007
> + * 04/11/08 Veerendra C <vechandr@in.ibm.com>
> + * Copyright (C) 2022 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
> + */
> +
> +/*\
> + * [Description]
> + *
> + * Clone a process with CLONE_NEWPID flag and verifies that siginfo->si_pid is
> + * set to 0 if sender (parent process) sent the signal. Then send signal from
> + * container itself and check if siginfo->si_pid is set to 1.
> + */
>
> #define _GNU_SOURCE 1
> -#include <stdio.h>
> -#include <stdlib.h>
> -#include <sys/wait.h>
> -#include <sys/types.h>
> #include <signal.h>
> -#include <unistd.h>
> -#include "pidns_helper.h"
> -#include "test.h"
> -
> -#define CHILD_PID 1
> -#define PARENT_PID 0
> +#include "tst_test.h"
> +#include "lapi/namespaces_constants.h"
>
> -char *TCID = "pidns16";
> -int TST_TOTAL = 3;
> +static volatile int exp_pid;
> +static volatile int passed;
>
> -void child_signal_handler(int sig, siginfo_t * si, void *unused)
> +static void child_signal_handler(LTP_ATTRIBUTE_UNUSED int sig, siginfo_t *si, LTP_ATTRIBUTE_UNUSED void *unused)
> {
> - static int c = 1;
> - pid_t expected_pid;
> -
> - /* Verifying from which process the signal handler is signalled */
> -
> - switch (c) {
> - case 1:
> - expected_pid = PARENT_PID;
> - break;
> - case 2:
> - expected_pid = CHILD_PID;
> - break;
> - default:
> - tst_resm(TBROK, "child should NOT be signalled 3+ times");
> - return;
> - }
> + tst_res(TINFO, "Received signal %s from PID %d",
> tst_strsig(si->si_signo), si->si_pid);
I missed this on pidns12. We are calling tst_res in a signal
handler which Cyril warned against
"The bigger problem though is that we call tst_brk() and tst_res() in the
handler, which is not safe at all. The are couple things that can go
wrong here, mostly glibc locks can get deadlocked for the underlying
FILE* and if the underlying fprintf() calls malloc() the malloc data
structures may end up corrupted. It's quite rare for this to happen, but
there have been a few tests that were failing with small probability due
to these mistakes."
We should only save the values in the sighandler and check them in the
main child function.
>
> - if (si->si_pid == expected_pid)
> - tst_resm(TPASS, "child is signalled from expected pid %d",
> - expected_pid);
> - else
> - tst_resm(TFAIL, "child is signalled from unexpected pid %d,"
> - " expecting pid %d", si->si_pid, expected_pid);
> + if (si->si_signo != SIGUSR1)
> + return;
>
> - c++;
> + if (si->si_pid == exp_pid)
> + passed = 1;
> }
>
> -/*
> - * child_fn() - Inside container
> - */
> -int child_fn(void *ttype)
> +static int child_func(LTP_ATTRIBUTE_UNUSED void *arg)
> {
> struct sigaction sa;
> - pid_t pid, ppid;
> + pid_t cpid, ppid;
>
> - /* Set process id and parent pid */
> - pid = getpid();
> + cpid = getpid();
> ppid = getppid();
>
> - if ((pid != CHILD_PID) || (ppid != PARENT_PID))
> - tst_resm(TBROK, "pidns is not created.");
> + if (cpid != 1 || ppid != 0) {
> + tst_res(TFAIL, "Got unexpected result of cpid=%d ppid=%d", cpid, ppid);
> + return 1;
Same with TST_EXP_EQ
> + }
>
> - /* Set signal handler for SIGUSR1, also mask other signals */
> sa.sa_flags = SA_SIGINFO;
> - sigemptyset(&sa.sa_mask);
> + SAFE_SIGFILLSET(&sa.sa_mask);
> sa.sa_sigaction = child_signal_handler;
> - if (sigaction(SIGUSR1, &sa, NULL) == -1)
> - tst_resm(TBROK, "%d: sigaction() failed", pid);
> -
> - pause();
> - tst_resm(TINFO, "Container: Resumed after receiving SIGUSR1 "
> - "from parentNS ");
> - if (kill(pid, SIGUSR1) != 0) {
> - tst_resm(TFAIL, "kill(SIGUSR1) fails.");
> - }
> - tst_resm(TINFO, "Container: Resumed after sending SIGUSR1 "
> - "from container itself");
> - _exit(10);
> -}
>
> -static void setup(void)
> -{
> - tst_require_root();
> - check_newpid();
> -}
> + SAFE_SIGACTION(SIGUSR1, &sa, NULL);
>
> -/***********************************************************************
> -* M A I N
> -***********************************************************************/
> -int main()
> -{
> - int status;
> - pid_t cpid;
> + passed = 0;
> + exp_pid = 0;
>
> - setup();
> + TST_CHECKPOINT_WAKE_AND_WAIT(0);
>
> - cpid = ltp_clone_quick(CLONE_NEWPID | SIGCHLD, child_fn, NULL);
> + if (passed)
> + tst_res(TPASS, "Container resumed after receiving SIGUSR1 from parent namespace");
> + else
> + tst_res(TFAIL, "Container did not receive the SIGUSR1 signal from parent");
>
> - if (cpid < 0) {
> - tst_resm(TBROK, "clone() failed.");
> - }
> + passed = 0;
> + exp_pid = 1;
>
> - sleep(1);
> - if (kill(cpid, SIGUSR1) != 0) {
> - tst_resm(TFAIL, "kill(SIGUSR1) fails.");
> - }
> - sleep(1);
> - if (waitpid(cpid, &status, 0) < 0)
> - tst_resm(TWARN, "waitpid() failed.");
> + SAFE_KILL(cpid, SIGUSR1);
>
> - if ((WIFEXITED(status)) && (WEXITSTATUS(status) == 10))
> - tst_resm(TPASS, "container init continued successfuly, "
> - "after handling signal -USR1");
> + if (passed)
> + tst_res(TPASS, "Container resumed after receiving SIGUSR1 from container namespace");
> else
> - tst_resm(TFAIL, "c-init failed to continue after "
> - "passing kill -USR1");
> - tst_exit();
> + tst_res(TFAIL, "Container did not receive the SIGUSR1 signal from container");
> +
> + return 0;
> +}
> +
> +static void run(void)
> +{
> + int ret;
> +
> + ret = ltp_clone_quick(CLONE_NEWPID | SIGCHLD, child_func, NULL);
> + if (ret < 0)
> + tst_brk(TBROK | TERRNO, "clone failed");
> +
> + TST_CHECKPOINT_WAIT(0);
> +
> + SAFE_KILL(ret, SIGUSR1);
> +
> + TST_CHECKPOINT_WAKE(0);
> }
> +
> +static struct tst_test test = {
> + .test_all = run,
> + .needs_root = 1,
> + .needs_checkpoints = 1,
> +};
> --
> 2.35.3
--
Thank you,
Richard.
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