From: Jann Horn <jannh@google.com>
To: Christian Kellner <ckellner@redhat.com>
Cc: kernel list <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Christian Kellner <christian@kellner.me>,
Christian Brauner <christian@brauner.io>,
Shuah Khan <shuah@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Michal Hocko <mhocko@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Elena Reshetova <elena.reshetova@intel.com>,
Roman Gushchin <guro@fb.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Al Viro <viro@zeniv.linux.org.uk>,
"Dmitry V. Levin" <ldv@altlinux.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] pidfd: add tests for NSpid info in fdinfo
Date: Fri, 11 Oct 2019 17:09:29 +0200 [thread overview]
Message-ID: <CAG48ez0MyiTKO2MpNVQqavoTKo7FZXYAyohx1JTR=M9Uw=QJWQ@mail.gmail.com> (raw)
In-Reply-To: <20191009160532.20674-2-ckellner@redhat.com>
On Wed, Oct 9, 2019 at 6:10 PM Christian Kellner <ckellner@redhat.com> wrote:
> Add tests that check that if pid namespaces are configured the fdinfo
> file of a pidfd contains an NSpid: entry containing the process id
> in the current and additionally all nested namespaces.
[...]
> +static int compare_fdinfo_nspid(int pidfd, char *expect, size_t len)
> +{
> + char path[512];
> + FILE *f;
> + size_t n = 0;
> + ssize_t k;
> + char *line = NULL;
> + int r = -1;
> +
> + snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
(Maybe at some point the selftests code should add some more concise
alternative to snprintf() calls on separate lines. A macro or
something like that so that you can write stuff like `f =
fopen(tprintf("/proc/self/fdinfo/%d", pidfd), "re")`.)
> + f = fopen(path, "re");
> + if (!f)
> + return -1;
> +
> + while ((k = getline(&line, &n, f)) != -1) {
> + if (strncmp(line, "NSpid:", 6))
> + continue;
> +
> + line[k - 1] = '\0';
> + ksft_print_msg("Child: fdinfo NSpid line: '%s'.\n", line);
> + r = strncmp(line + 6, expect, len);
Wouldn't it be better to get rid of the nullbyte assignment and change
the strncmp() into a strcmp() here...
[...]
> + /* The child will have pid 1 in the new pid namespace,
> + * so the line must be 'NSPid:\t<pid>\t1'
> + */
> + n = snprintf(expect, sizeof(expect), "\t%d\t%d", pid, 1);
... and add a "\n" to the format string? It's shorter and doesn't
silently ignore it if the line doesn't end at that point.
next prev parent reply other threads:[~2019-10-11 15:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191008133641.23019-1-ckellner@redhat.com>
[not found] ` <20191009160532.20674-1-ckellner@redhat.com>
2019-10-09 16:05 ` [PATCH v2 2/2] pidfd: add tests for NSpid info in fdinfo Christian Kellner
2019-10-11 15:09 ` Jann Horn [this message]
2019-10-11 17:08 ` Christian Brauner
[not found] ` <20191011122323.7770-1-ckellner@redhat.com>
2019-10-11 12:23 ` [PATCH v3 " Christian Kellner
2019-10-11 13:18 ` Christian Brauner
[not found] ` <20191014162034.2185-1-ckellner@redhat.com>
2019-10-14 16:20 ` [PATCH v4 " Christian Kellner
2019-10-15 10:07 ` Christian Brauner
2019-11-13 11:52 ` Naresh Kamboju
2019-11-13 12:20 ` Christian Brauner
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