Date: Sun, 23 Aug 2020 22:23:19 +0000 (UTC) From: Edward Tomasz Napierala <trasz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r364572 - stable/12/sys/compat/linux Message-ID: <202008232223.07NMNJv6098715@repo.freebsd.org>
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Author: trasz Date: Sun Aug 23 22:23:19 2020 New Revision: 364572 URL: https://svnweb.freebsd.org/changeset/base/364572 Log: MFC r363093: Make linux stat(2) return the same st_dev for every devfs instance. The reason for this is to work around an idiosyncrasy of glibc getttynam(3) implementation: it checks whether st_dev returned for fd 0 is the same as st_dev returned for the target of /proc/self/fd/0 symlink, and with linux chroots having their own devfs instance, the check will fail if you chrooted into it. PR: kern/240767 Sponsored by: The FreeBSD Foundation Modified: stable/12/sys/compat/linux/linux_stats.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/compat/linux/linux_stats.c ============================================================================== --- stable/12/sys/compat/linux/linux_stats.c Sun Aug 23 22:21:36 2020 (r364571) +++ stable/12/sys/compat/linux/linux_stats.c Sun Aug 23 22:23:19 2020 (r364572) @@ -70,6 +70,17 @@ translate_vnhook_major_minor(struct vnode *vp, struct sb->st_mode |= S_IFBLK; } + /* + * Return the same st_dev for every devfs instance. The reason + * for this is to work around an idiosyncrasy of glibc getttynam() + * implementation: it checks whether st_dev returned for fd 0 + * is the same as st_dev returned for the target of /proc/self/fd/0 + * symlink, and with linux chroots having their own devfs instance, + * the check will fail if you chroot into it. + */ + if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc) + sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0]; + if (vp->v_type == VCHR && vp->v_rdev != NULL && linux_driver_get_major_minor(devtoname(vp->v_rdev), &major, &minor) == 0) { @@ -110,6 +121,7 @@ translate_fd_major_minor(struct thread *td, int fd, st { struct file *fp; struct vnode *vp; + struct mount *mp; int major, minor; /* @@ -122,6 +134,12 @@ translate_fd_major_minor(struct thread *td, int fd, st if (vp != NULL && vn_isdisk(vp, NULL)) { buf->st_mode &= ~S_IFMT; buf->st_mode |= S_IFBLK; + } + if (vp != NULL && rootdevmp != NULL) { + mp = vp->v_mount; + __compiler_membar(); + if (mp != NULL && mp->mnt_vfc == rootdevmp->mnt_vfc) + buf->st_dev = rootdevmp->mnt_stat.f_fsid.val[0]; } if (vp != NULL && vp->v_rdev != NULL && linux_driver_get_major_minor(devtoname(vp->v_rdev),
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