From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933268AbcATLve (ORCPT ); Wed, 20 Jan 2016 06:51:34 -0500 Received: from mail-wm0-f41.google.com ([74.125.82.41]:33571 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932261AbcATLvb (ORCPT ); Wed, 20 Jan 2016 06:51:31 -0500 Subject: Re: [PATCH 4/5] scripts/gdb: Add mount point list command To: Jan Kiszka References: <1453288550-4706-1-git-send-email-kieran.bingham@linaro.org> <1453288550-4706-5-git-send-email-kieran.bingham@linaro.org> <569F7288.1080107@siemens.com> Cc: linux-kernel@vger.kernel.org, maxime.coquelin@st.com, peter.griffin@linaro.org, lee.jones@linaro.org From: Kieran Bingham X-Enigmail-Draft-Status: N1110 Message-ID: <569F74C1.7000209@linaro.org> Date: Wed, 20 Jan 2016 11:51:29 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <569F7288.1080107@siemens.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jan, On 20/01/16 11:42, Jan Kiszka wrote: > Hi Kieran, > > just a couple of quick comments: > > On 2016-01-20 12:15, Kieran Bingham wrote: >> lx-mounts will identify current mount points based on the 'init_task' >> namespace by default, as we do not yet have a kernel thread list >> implementation to select the current running thread. > > current_task? See LxCurrentFunc, could be factored out if usable. Or > what are you looking for? LxCurrentFunc relies on gdb.parse_and_eval("¤t_task") which is not available on ARM. Although that is not what I was referring to in the comment. My meaning was that once we have gdb-thread objects created, (my next phase of work) then this command would operate on the thread currently selected in gdb, based on the inferior_ptid. >> >> Optionally, a user can specify a PID to list from that process' >> namespace >> >> This is somewhat limited vs the /proc/mounts file, as that calls into >> vfs hooks through the s_op functions to obtain extra information. >> >> Signed-off-by: Kieran Bingham >> --- >> >> >> In this patch, I'm interested in your opinions on coding styles. >> Would you prefer to see the function helpers, (dentry_name, info_opts) where >> they are, or inside the command as class members? Or perhaps defined in utils? > > Need to look into this. > >> >> This also shows where I need to take constant information from the kernel. >> In this case, they are simple numerical bitflags, and unlikely to change but >> I didn't want to duplicate their values. > > Maybe we can generate python files with the required constants from the > C headers during build? Similar to asm-offsets.c stuff. > Yes, this is what I've implemented in [PATCH 1/5] ? Perhaps the mails have reached you out-of-order. >> >> >> scripts/gdb/linux/constants.py.in | 21 ++++++++ >> scripts/gdb/linux/proc.py | 110 ++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 131 insertions(+) >> >> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in >> index d84084ac945b..739a15d2e984 100644 >> --- a/scripts/gdb/linux/constants.py.in >> +++ b/scripts/gdb/linux/constants.py.in >> @@ -12,7 +12,11 @@ >> * >> */ >> >> +#include >> +#include >> + >> /* We need to stringify expanded macros so that they can be parsed */ >> #define STRING(x) #x >> #define XSTRING(x) STRING(x) >> >> @@ -20,3 +24,20 @@ >> >> >> import gdb >> + >> +/* linux/fs.h */ >> +LX_MS_RDONLY = MS_RDONLY >> +LX_MS_SYNCHRONOUS = MS_SYNCHRONOUS >> +LX_MS_MANDLOCK = MS_MANDLOCK >> +LX_MS_DIRSYNC = MS_DIRSYNC >> +LX_MS_NOATIME = MS_NOATIME >> +LX_MS_NODIRATIME = MS_NODIRATIME >> + >> +/* linux/mount.h */ >> +LX_MNT_NOSUID = MNT_NOSUID >> +LX_MNT_NODEV = MNT_NODEV >> +LX_MNT_NOEXEC = MNT_NOEXEC >> +LX_MNT_NOATIME = MNT_NOATIME >> +LX_MNT_NODIRATIME = MNT_NODIRATIME >> +LX_MNT_RELATIME = MNT_RELATIME >> + >> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py >> index d855b2fd9a06..b79ce2a33a3d 100644 >> --- a/scripts/gdb/linux/proc.py >> +++ b/scripts/gdb/linux/proc.py >> @@ -12,6 +12,10 @@ >> # >> >> import gdb >> +from linux import constants >> +from linux import utils >> +from linux import tasks >> +from linux import lists >> >> >> class LxCmdLine(gdb.Command): >> @@ -96,3 +100,109 @@ Equivalent to cat /proc/ioports on a running target""" >> return show_lx_resources("ioport_resource") >> >> LxIOPorts() >> + >> + >> +# Mount namespace viewer >> +# /proc/mounts >> + >> + >> +def dentry_name(d): >> + if d['d_parent'] == d: >> + return "" >> + p = dentry_name(d['d_parent']) + "/" >> + return p + d['d_iname'].string() >> + >> + >> +def info_opts(lst, opt): >> + opts = "" >> + for key, string in lst.items(): >> + if opt & key: >> + opts += string >> + return opts >> + >> + >> +FS_INFO = {constants.LX_MS_SYNCHRONOUS: ",sync", >> + constants.LX_MS_MANDLOCK: ",mand", >> + constants.LX_MS_DIRSYNC: ",dirsync", >> + constants.LX_MS_NOATIME: ",noatime", >> + constants.LX_MS_NODIRATIME: ",nodiratime"} >> + >> +MNT_INFO = {constants.LX_MNT_NOSUID: ",nosuid", >> + constants.LX_MNT_NODEV: ",nodev", >> + constants.LX_MNT_NOEXEC: ",noexec", >> + constants.LX_MNT_NOATIME: ",noatime", >> + constants.LX_MNT_NODIRATIME: ",nodiratime", >> + constants.LX_MNT_RELATIME: ",relatime"} >> + >> +mount_type = utils.CachedType("struct mount") >> +mount_ptr_type = mount_type.get_type().pointer() >> + >> + >> +class LxMounts(gdb.Command): >> + """Report the VFS mounts of the current process namespace. >> + >> +Equivalent to cat /proc/mounts on a running target >> +An integer value can be supplied to display the mount >> +values of that process namespace""" >> + >> + def __init__(self): >> + super(LxMounts, self).__init__("lx-mounts", gdb.COMMAND_DATA) >> + >> + # Equivalent to proc_namespace.c:show_vfsmnt >> + # However, that has the ability to call into s_op functions >> + # whereas we cannot and must make do with the information we can obtain. >> + def invoke(self, arg, from_tty): >> + argv = gdb.string_to_argv(arg) >> + if len(argv) >= 1: >> + try: >> + pid = int(argv[0]) >> + except: >> + raise gdb.GdbError("Provide a PID as integer value") >> + else: >> + pid = 1 >> + >> + task = tasks.get_task_by_pid(pid) >> + if not task: >> + raise gdb.GdbError("Couldn't find a process with PID {}" >> + .format(pid)) >> + >> + namespace = task['nsproxy']['mnt_ns'] >> + if not namespace: >> + raise gdb.GdbError("No namespace for current process") >> + >> + for vfs in lists.items(mount_ptr_type, "mnt_list", namespace['list']): >> + # There appears to be a null entry at the end of the list... >> + if not vfs['mnt_parent']: >> + break >> + >> + devname = vfs['mnt_devname'].string() >> + devname = devname if devname else "none" >> + >> + pathname = "" >> + parent = vfs >> + while True: >> + mntpoint = parent['mnt_mountpoint'] >> + pathname = dentry_name(mntpoint) + pathname >> + if (parent == parent['mnt_parent']): >> + break >> + parent = parent['mnt_parent'] >> + >> + if (pathname == ""): >> + pathname = "/" >> + >> + superblock = vfs['mnt']['mnt_sb'] >> + fstype = superblock['s_type']['name'].string() >> + s_flags = int(superblock['s_flags']) >> + m_flags = int(vfs['mnt']['mnt_flags']) >> + rd = "ro" if (s_flags & constants.LX_MS_RDONLY) else "rw" >> + >> + gdb.write( >> + "{} {} {} {}{}{} 0 0\n" >> + .format(devname, >> + pathname, >> + fstype, >> + rd, >> + info_opts(FS_INFO, s_flags), >> + info_opts(MNT_INFO, m_flags))) >> + >> +LxMounts() >> >