| Message ID | 1453288550-4706-5-git-send-email-kieran.bingham@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
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 <kieran.bingham@linaro.org> >> --- >> >> >> 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 <linux/fs.h> >> +#include <linux/mount.h> >> + >> /* 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 @@ >> <!-- end-c-headers --> >> >> 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() >> >
On 23/01/16 15:27, Jan Kiszka wrote: > 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. >> >> 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 <kieran.bingham@linaro.org> >> --- >> >> >> 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? > > Do you think they could be useful beyond this class? If not, stick them > inside. Refactoring can still be done once they are needed. > Ok - that's good logic. Keep them close until needed elsewhere :) >> >> 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. >> >> >> 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 <linux/fs.h> >> +#include <linux/mount.h> >> + >> /* 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 @@ >> <!-- end-c-headers --> >> >> 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... > > "There appears to be" - hmm... Did you check this against the code? Not properly no... I'll check and see what happened. I'll have a think as to the best defences to put in. This one stopped a NULL dereference on mine, but as below clearly it didn't stop them all! > >> + 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 > > I'm getting an error in this line: > > (gdb) lx-mounts > devtmpfs /dev devtmpfs rw,relatime 0 0 > tmpfs /dev/shm tmpfs rw,relatime 0 0 > devpts /dev/pts devpts rw,relatime 0 0 > /dev/sda2 / ext4 rw,relatime 0 0 > proc /proc proc rw,nodiratime,relatime 0 0 > sysfs /sys sysfs rw,relatime 0 0 > debugfs /sys/kernel/debug debugfs rw,relatime 0 0 > securityfs /sys/kernel/security securityfs rw,relatime 0 0 > fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0 > gvfs-fuse-daemon /home/jan/.gvfs fuse rw,relatime,nosuid,nodev 0 0 > tracefs /sys/kernel/debug/tracing tracefs rw,relatime 0 0 > Traceback (most recent call last): > File "/data/linux/build-dbg/scripts/gdb/linux/proc.py", line 185, in invoke > pathname = dentry_name(mntpoint) + pathname > File "/data/linux/build-dbg/scripts/gdb/linux/proc.py", line 112, in dentry_name > p = dentry_name(d['d_parent']) + "/" > File "/data/linux/build-dbg/scripts/gdb/linux/proc.py", line 110, in dentry_name > if d['d_parent'] == d: > gdb.MemoryError: Cannot access memory at address 0x40 > Error occurred in Python command: Cannot access memory at address 0x40 > > In this case, the dump should have stopped after the tracefs line. > Interesting, I'll have to be more defensive. I'm sure when I looked the proc show command seemed to have only the list end and the dev name checks... But we could by our nature run at any time - so it should be a bit more defensive anyway >> + 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() >> > > Jan > Kieran
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 <linux/fs.h> +#include <linux/mount.h> + /* 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 @@ <!-- end-c-headers --> 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()
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. 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 <kieran.bingham@linaro.org> --- 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? 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. scripts/gdb/linux/constants.py.in | 21 ++++++++ scripts/gdb/linux/proc.py | 110 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 131 insertions(+) -- 2.5.0