Re: [uml-devel] Hostfs permission checks are all wonky.

[Rob Landley <rob@landley.net>]

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On Thursday 24 March 2005 05:53 am, Blaisorblade wrote:

> > Try it, it's easy.
> >
> > ./linux rootfstype=hostfs rootflags=/ rw init=/bin/sh
> >
> > If you run it from an xterm, that should work.  If you run it from an ssh
> > session, it probably won't because of the permissions on /dev/console
> > discussed above.
>
> I'm not understanding the difference at the moment...

I just meant that startx (which is root) chmods /dev/console to belong to the 
user who ran X11.  Under a normal text console, /dev/console belongs to root.  
(So sometimes it would refuse to run and sometimes it wouldn't, and it took a 
little while to figure out what was wrong.)

This is not a problem with your patch applied.

> > It does that all the time.  (The id=? bit changes with each run.)
> > Somewhere around here I've got a trace from when I built it with debug
> > symbols, I can get that for you at the same time I try out your patch...
>
> I'd like that a lot, and also your .config - I've never seen that message
> nor I know the users of that kernel internal API (but probably UML itself
> isn't using that).

Well, here's the .config, anyway.  I don't know where the debug trace is at 
the moment, so I'll recompile with debug symbols to try to replicate with 
debug info now.  (It happens a LOT for me, on several different machines.  
Possibly related to using hostfs as root... :)

Rob

[-- Attachment #2: linux-config-um --]
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#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.11-rc4
# Sat Feb 19 14:32:29 2005
#
CONFIG_GENERIC_HARDIRQS=y
CONFIG_USERMODE=y
CONFIG_MMU=y
CONFIG_UID16=y
CONFIG_RWSEM_GENERIC_SPINLOCK=y
CONFIG_GENERIC_CALIBRATE_DELAY=y

#
# UML-specific options
#
CONFIG_MODE_TT=y
CONFIG_MODE_SKAS=y
# CONFIG_64_BIT is not set
CONFIG_TOP_ADDR=0xc0000000
# CONFIG_3_LEVEL_PGTABLES is not set
CONFIG_ARCH_HAS_SC_SIGNALS=y
CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA=y
CONFIG_LD_SCRIPT_STATIC=y
# CONFIG_NET is not set
CONFIG_BINFMT_ELF=y
# CONFIG_BINFMT_MISC is not set
CONFIG_HOSTFS=y
# CONFIG_MCONSOLE is not set
# CONFIG_HOST_2G_2G is not set
CONFIG_NEST_LEVEL=0
CONFIG_KERNEL_HALF_GIGS=1
CONFIG_KERNEL_STACK_ORDER=2
# CONFIG_UML_REAL_TIME_CLOCK is not set

#
# Code maturity level options
#
# CONFIG_EXPERIMENTAL is not set
CONFIG_CLEAN_COMPILE=y
CONFIG_BROKEN_ON_SMP=y

#
# General setup
#
CONFIG_LOCALVERSION=""
# CONFIG_SWAP is not set
# CONFIG_SYSVIPC is not set
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_SYSCTL is not set
# CONFIG_AUDIT is not set
CONFIG_LOG_BUF_SHIFT=14
CONFIG_HOTPLUG=y
# CONFIG_IKCONFIG is not set
CONFIG_EMBEDDED=y
# CONFIG_KALLSYMS is not set
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
# CONFIG_SHMEM is not set
CONFIG_CC_ALIGN_FUNCTIONS=0
CONFIG_CC_ALIGN_LABELS=0
CONFIG_CC_ALIGN_LOOPS=0
CONFIG_CC_ALIGN_JUMPS=0
CONFIG_TINY_SHMEM=y

#
# Loadable module support
#
# CONFIG_MODULES is not set

#
# Generic Driver Options
#
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
# CONFIG_FW_LOADER is not set

#
# Character Devices
#
CONFIG_STDERR_CONSOLE=y
CONFIG_STDIO_CONSOLE=y
# CONFIG_SSL is not set
# CONFIG_NULL_CHAN is not set
# CONFIG_PORT_CHAN is not set
# CONFIG_PTY_CHAN is not set
# CONFIG_TTY_CHAN is not set
# CONFIG_XTERM_CHAN is not set
CONFIG_NOCONFIG_CHAN=y
CONFIG_CON_ZERO_CHAN="fd:0,fd:1"
CONFIG_CON_CHAN="xterm"
CONFIG_SSL_CHAN="pty"
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_WATCHDOG is not set
# CONFIG_UML_SOUND is not set
# CONFIG_SOUND is not set
# CONFIG_HOSTAUDIO is not set

#
# Block devices
#
# CONFIG_BLK_DEV_UBD is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
CONFIG_BLK_DEV_LOOP=y
# CONFIG_BLK_DEV_CRYPTOLOOP is not set
# CONFIG_BLK_DEV_RAM is not set
CONFIG_BLK_DEV_RAM_COUNT=16
CONFIG_INITRAMFS_SOURCE=""
CONFIG_LBD=y

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
# CONFIG_IOSCHED_AS is not set
# CONFIG_IOSCHED_DEADLINE is not set
# CONFIG_IOSCHED_CFQ is not set
# CONFIG_NETDEVICES is not set

#
# Networking support
#
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set

#
# File systems
#
CONFIG_EXT2_FS=y
# CONFIG_EXT2_FS_XATTR is not set
# CONFIG_EXT3_FS is not set
# CONFIG_JBD is not set
# CONFIG_REISERFS_FS is not set
# CONFIG_JFS_FS is not set

#
# XFS support
#
# CONFIG_XFS_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_ROMFS_FS is not set
# CONFIG_QUOTA is not set
# CONFIG_DNOTIFY is not set
# CONFIG_AUTOFS_FS is not set
# CONFIG_AUTOFS4_FS is not set

#
# CD-ROM/DVD Filesystems
#
# CONFIG_ISO9660_FS is not set
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
# CONFIG_MSDOS_FS is not set
# CONFIG_VFAT_FS is not set
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
# CONFIG_PROC_KCORE is not set
# CONFIG_SYSFS is not set
# CONFIG_DEVPTS_FS_XATTR is not set
# CONFIG_TMPFS is not set
# CONFIG_HUGETLB_PAGE is not set
CONFIG_RAMFS=y

#
# Miscellaneous filesystems
#
# CONFIG_HFSPLUS_FS is not set
# CONFIG_CRAMFS is not set
CONFIG_SQUASHFS=y
# CONFIG_VXFS_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y

#
# Native Language Support
#
# CONFIG_NLS is not set

#
# Security options
#
# CONFIG_KEYS is not set
# CONFIG_SECURITY is not set

#
# Cryptographic options
#
# CONFIG_CRYPTO is not set

#
# Hardware crypto devices
#

#
# Library routines
#
# CONFIG_CRC_CCITT is not set
# CONFIG_CRC32 is not set
# CONFIG_LIBCRC32C is not set
CONFIG_ZLIB_INFLATE=y

#
# Multi-device support (RAID and LVM)
#
# CONFIG_MD is not set
# CONFIG_INPUT is not set

#
# Kernel hacking
#
# CONFIG_DEBUG_KERNEL is not set