From: Jann Horn <jannh@google.com> To: Christian Brauner <christian@brauner.io> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>, Andy Lutomirski <luto@kernel.org>, David Howells <dhowells@redhat.com>, "Serge E. Hallyn" <serge@hallyn.com>, "Eric W. Biederman" <ebiederm@xmission.com>, Linux API <linux-api@vger.kernel.org>, kernel list <linux-kernel@vger.kernel.org>, Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>, Alexey Dobriyan <adobriyan@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Michael Kerrisk-manpages <mtk.manpages@gmail.com>, bl0pbl33p@gmail.com, "Dmitry V. Levin" <ldv@altlinux.org>, Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>, cyphar@cyphar.com, Al Viro <viro@zeniv.linux.org.uk>, "Joel Fernandes (Google)" <joel@joelfernandes.org>, Daniel Colascione <dancol@google.com> Subject: Re: [PATCH 3/4] signal: support pidctl() with pidfd_send_signal() Date: Mon, 25 Mar 2019 19:39:25 +0100 [thread overview] Message-ID: <CAG48ez1QSJTOb-DAQuVpa5feUe9K-pr8aYuyd=yXg0n9eSg-LQ@mail.gmail.com> (raw) In-Reply-To: <20190325162052.28987-4-christian@brauner.io> On Mon, Mar 25, 2019 at 5:21 PM Christian Brauner <christian@brauner.io> wrote: > Let pidfd_send_signal() use pidfds retrieved via pidctl(). With this patch > pidfd_send_signal() becomes independent of procfs. This fullfils the > request made when we merged the pidfd_send_signal() patchset. The > pidfd_send_signal() syscall is now always available allowing for it to be > used by users without procfs mounted or even users without procfs support > compiled into the kernel. [...] > static bool access_pidfd_pidns(struct pid *pid) > { > + int ret; > struct pid_namespace *active = task_active_pid_ns(current); > struct pid_namespace *p = ns_of_pid(pid); > > - for (;;) { > - if (!p) > - return false; > - if (p == active) > - break; > - p = p->parent; > - } > + ret = pidnscmp(active, p); > + if (ret < 0) > + return false; > > return true; > } Nit, if we keep this function: "if (...) return false; return true;" seems like an antipattern to me. How about "return ret >= 0", or even "return pidnscmp(active, p) >= 0"?
WARNING: multiple messages have this Message-ID (diff)
From: Jann Horn <jannh@google.com> To: Christian Brauner <christian@brauner.io> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>, Andy Lutomirski <luto@kernel.org>, David Howells <dhowells@redhat.com>, "Serge E. Hallyn" <serge@hallyn.com>, "Eric W. Biederman" <ebiederm@xmission.com>, Linux API <linux-api@vger.kernel.org>, kernel list <linux-kernel@vger.kernel.org>, Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>, Alexey Dobriyan <adobriyan@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Michael Kerrisk-manpages <mtk.manpages@gmail.com>, bl0pbl33p@gmail.com, "Dmitry V. Levin" <ldv@altlinux.org>, Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com>, cyphar@cyphar.com, Al Viro <viro@zeniv.linux.org.uk>, "Joel Fernandes (Google)" <joe> Subject: Re: [PATCH 3/4] signal: support pidctl() with pidfd_send_signal() Date: Mon, 25 Mar 2019 19:39:25 +0100 [thread overview] Message-ID: <CAG48ez1QSJTOb-DAQuVpa5feUe9K-pr8aYuyd=yXg0n9eSg-LQ@mail.gmail.com> (raw) In-Reply-To: <20190325162052.28987-4-christian@brauner.io> On Mon, Mar 25, 2019 at 5:21 PM Christian Brauner <christian@brauner.io> wrote: > Let pidfd_send_signal() use pidfds retrieved via pidctl(). With this patch > pidfd_send_signal() becomes independent of procfs. This fullfils the > request made when we merged the pidfd_send_signal() patchset. The > pidfd_send_signal() syscall is now always available allowing for it to be > used by users without procfs mounted or even users without procfs support > compiled into the kernel. [...] > static bool access_pidfd_pidns(struct pid *pid) > { > + int ret; > struct pid_namespace *active = task_active_pid_ns(current); > struct pid_namespace *p = ns_of_pid(pid); > > - for (;;) { > - if (!p) > - return false; > - if (p == active) > - break; > - p = p->parent; > - } > + ret = pidnscmp(active, p); > + if (ret < 0) > + return false; > > return true; > } Nit, if we keep this function: "if (...) return false; return true;" seems like an antipattern to me. How about "return ret >= 0", or even "return pidnscmp(active, p) >= 0"?
next prev parent reply other threads:[~2019-03-25 18:39 UTC|newest] Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-25 16:20 [PATCH 0/4] pid: add pidctl() Christian Brauner 2019-03-25 16:20 ` [PATCH 1/4] Make anon_inodes unconditional Christian Brauner 2019-03-25 16:20 ` [PATCH 2/4] pid: add pidctl() Christian Brauner 2019-03-25 17:20 ` Mika Penttilä 2019-03-25 19:59 ` Christian Brauner 2019-03-25 19:59 ` Christian Brauner 2019-03-25 18:18 ` Jann Horn 2019-03-25 18:18 ` Jann Horn 2019-03-25 19:58 ` Christian Brauner 2019-03-25 19:58 ` Christian Brauner 2019-03-26 16:07 ` Joel Fernandes 2019-03-26 16:07 ` Joel Fernandes 2019-03-26 16:15 ` Christian Brauner 2019-03-26 16:15 ` Christian Brauner 2019-03-25 16:20 ` [PATCH 3/4] signal: support pidctl() with pidfd_send_signal() Christian Brauner 2019-03-25 18:28 ` Jonathan Kowalski 2019-03-25 18:28 ` Jonathan Kowalski 2019-03-25 20:05 ` Christian Brauner 2019-03-25 20:05 ` Christian Brauner 2019-03-25 18:39 ` Jann Horn [this message] 2019-03-25 18:39 ` Jann Horn 2019-03-25 19:41 ` Christian Brauner 2019-03-25 19:41 ` Christian Brauner 2019-03-25 16:20 ` [PATCH 4/4] tests: add pidctl() tests Christian Brauner 2019-03-25 16:48 ` [PATCH 0/4] pid: add pidctl() Daniel Colascione 2019-03-25 16:48 ` Daniel Colascione 2019-03-25 17:05 ` Konstantin Khlebnikov 2019-03-25 17:07 ` Daniel Colascione 2019-03-25 17:07 ` Daniel Colascione 2019-03-25 17:36 ` Joel Fernandes 2019-03-25 17:36 ` Joel Fernandes 2019-03-25 17:53 ` Daniel Colascione 2019-03-25 17:53 ` Daniel Colascione 2019-03-25 18:19 ` Jonathan Kowalski 2019-03-25 18:19 ` Jonathan Kowalski 2019-03-25 18:57 ` Daniel Colascione 2019-03-25 18:57 ` Daniel Colascione 2019-03-25 19:42 ` Jonathan Kowalski 2019-03-25 19:42 ` Jonathan Kowalski 2019-03-25 20:14 ` Daniel Colascione 2019-03-25 20:14 ` Daniel Colascione 2019-03-25 20:34 ` Jann Horn 2019-03-25 20:34 ` Jann Horn 2019-03-25 20:40 ` Jonathan Kowalski 2019-03-25 20:40 ` Jonathan Kowalski 2019-03-25 21:14 ` Jonathan Kowalski 2019-03-25 21:14 ` Jonathan Kowalski 2019-03-25 21:15 ` Jann Horn 2019-03-25 21:15 ` Jann Horn 2019-03-25 20:40 ` Christian Brauner 2019-03-25 20:40 ` Christian Brauner 2019-03-25 20:15 ` Christian Brauner 2019-03-25 20:15 ` Christian Brauner 2019-03-25 21:11 ` Joel Fernandes 2019-03-25 21:11 ` Joel Fernandes 2019-03-25 21:17 ` Daniel Colascione 2019-03-25 21:17 ` Daniel Colascione 2019-03-25 21:19 ` Jann Horn 2019-03-25 21:19 ` Jann Horn 2019-03-25 21:43 ` Joel Fernandes 2019-03-25 21:43 ` Joel Fernandes 2019-03-25 21:54 ` Jonathan Kowalski 2019-03-25 21:54 ` Jonathan Kowalski 2019-03-25 22:07 ` Daniel Colascione 2019-03-25 22:07 ` Daniel Colascione 2019-03-25 22:37 ` Jonathan Kowalski 2019-03-25 22:37 ` Jonathan Kowalski 2019-03-25 23:14 ` Daniel Colascione 2019-03-25 23:14 ` Daniel Colascione 2019-03-26 3:03 ` Joel Fernandes 2019-03-26 3:03 ` Joel Fernandes 2019-03-25 16:56 ` David Howells 2019-03-25 16:56 ` David Howells 2019-03-25 16:58 ` Daniel Colascione 2019-03-25 16:58 ` Daniel Colascione 2019-03-25 23:39 ` Andy Lutomirski 2019-03-25 23:39 ` Andy Lutomirski
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