From owner-freebsd-emulation@freebsd.org Fri Jul 3 22:33:56 2020 Return-Path: Delivered-To: freebsd-emulation@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id A8A2235AC72 for ; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 49z8rh45Hxz3bSZ for ; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id 8C5E335B32A; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) Delivered-To: emulation@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 8C26B35B145 for ; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49z8rh3Cnsz3bX5 for ; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 5210E12C8E for ; Fri, 3 Jul 2020 22:33:56 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 063MXuno068024 for ; Fri, 3 Jul 2020 22:33:56 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 063MXuwW068023 for emulation@FreeBSD.org; Fri, 3 Jul 2020 22:33:56 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: emulation@FreeBSD.org Subject: [Bug 240767] linprocfs(4) - /proc/fd is weird Date: Fri, 03 Jul 2020 22:33:56 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: trasz@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: emulation@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Jul 2020 22:33:56 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D240767 --- Comment #2 from Edward Tomasz Napierala --- Okay, so after another afternoon spent debugging this stuff, here's how it looks: First, glibc (namely gettyname()) requires contents of /proc/self/fd/ to be symlinks. Turns out it's trivial to make it work, and it's even documented: just mount fdescfs with 'linrdlnk' option. I'll make /etc/rc.d/linux defau= lt to it soon. Problem is: it doesn't work when you chroot into your Linux root (eg /compat/linux). For some reason glibc tries to be very, _very_ careful with the name it got from /proc/self/fd/0; it calls stat(2) on fd 0, and then on= the symlink target, and compares st_dev. When chrooted to /compat/linux, your stdin is on /dev, while /proc/self/fd/0 (really /compat/linux/proc/self/fd/= 0) points to /dev/fd/0 (really /compat/linux/dev/fd/0); since /dev and /compat/linux/dev have different fsids, and thus stat(2) returns different st_dev, the glibc check fails. Workaround: run sshd inside your linux chroot and ssh into localhost. Meh. --=20 You are receiving this mail because: You are the assignee for the bug.=