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[209.85.219.181]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7023a989d27sm6487797b3.86.2025.03.28.05.17.18 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Mar 2025 05:17:19 -0700 (PDT) Received: by mail-yb1-f181.google.com with SMTP id 3f1490d57ef6-e643f234e08so1686258276.0 for ; Fri, 28 Mar 2025 05:17:18 -0700 (PDT) X-Received: by 2002:a05:6902:1685:b0:e5d:cb26:cdaf with SMTP id 3f1490d57ef6-e69437aa881mr9738327276.42.1743164238727; Fri, 28 Mar 2025 05:17:18 -0700 (PDT) List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@FreeBSD.org MIME-Version: 1.0 References: In-Reply-To: From: Gleb Popov Date: Fri, 28 Mar 2025 15:16:52 +0300 X-Gmail-Original-Message-ID: X-Gm-Features: AQ5f1JrbVK0McKSazMuLLqYkhjSbt4PXPavpNqdEODCvHuLyWVJphXxSOTyRvbQ Message-ID: Subject: Re: Would we want pidfd_open(2) & SO_PEERPIDFD? To: freebsd-hackers Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spamd-Result: default: False [2.09 / 15.00]; SUBJECT_ENDS_QUESTION(1.00)[]; NEURAL_SPAM_LONG(1.00)[1.000]; NEURAL_HAM_SHORT(-0.99)[-0.994]; NEURAL_SPAM_MEDIUM(0.98)[0.979]; FORGED_SENDER(0.30)[arrowd@freebsd.org,6yearold@gmail.com]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17:c]; DMARC_POLICY_SOFTFAIL(0.10)[freebsd.org : SPF not aligned (relaxed), No valid DKIM,none]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; RCVD_TLS_LAST(0.00)[]; ARC_NA(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_ALL(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_NEQ_ENVFROM(0.00)[arrowd@freebsd.org,6yearold@gmail.com]; RBL_SENDERSCORE_REPUT_8(0.00)[209.85.128.172:from]; TO_DOM_EQ_FROM_DOM(0.00)[]; R_DKIM_NA(0.00)[]; MLMMJ_DEST(0.00)[freebsd-hackers@freebsd.org]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; RWL_MAILSPIKE_POSSIBLE(0.00)[209.85.128.172:from]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[209.85.128.172:from,209.85.219.181:received]; MISSING_XM_UA(0.00)[]; FROM_HAS_DN(0.00)[] X-Rspamd-Queue-Id: 4ZPKKF43HMz3nMF X-Spamd-Bar: ++ On Tue, Mar 25, 2025 at 8:27=E2=80=AFAM Gleb Popov wro= te: > > The high level code expects a descriptor with some properties, so we > either provide it or have to patch large parts of the code using it. > Emulating pidfd somehow is also fine to me, but I have no idea how to > do that. libinotify-kqueue example shows that emulating a descriptor > with certain properties is quite a non-trivial task. A bit orthogonal to the Capsicum discussion, I wonder if the following idea makes sense: We do have FUSE as a framework to implement filesystems from the userspace, same goes for CUSE that allows for programming character devices. Maybe having some sort of FDUSE providing a way to create "custom" descriptors and define their behaviour from userspace would be useful?