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+[[!meta copyright="Copyright © 2010, 2011, 2013, 2014 Free Software Foundation,
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
+is included in the section entitled [[GNU Free Documentation
+[[!tag open_issue_glibc open_issue_hurd]]
+# IRC, freenode, #hurd, June (?) 2010
+ <pochu> is there a way (POSIX or Hurdish) to get the corresponding file
+ name for a fd or a hurd port?
+ <marcusb> there is a way
+ <pochu> marcusb: which one would that be?
+ <marcusb> I forgot
+ <marcusb> there is an implementation in libc
+ <marcusb> realpath has a similar job
+ <marcusb> but that's not what I mean
+ <marcusb> pochu: maybe I am misremembering. But it was something where you
+ keep looking up .. and list that directory, looking for the node with the
+ ID of the node you had .. for
+ <marcusb> maybe it works only for directories
+ <marcusb> yeah
+ <marcusb> pochu: check the getcwd() implementation of libc
+ <marcusb> sysdeps/mach/hurd/getcwd.c
+ <marcusb> _hurd_canonicalize_directory_name_internal 
+ * pochu looks
+ <pochu> marcusb: interesting
+ <pochu> though that is for dirs, and doesn't seem to be extensible to
+ files, as you cannot lookup for ".." under a file
+ <marcusb> right
+ <pochu> oh you already said that :)
+ <marcusb> actually, I am not sure that's correct
+ <marcusb> it's probably correct, but there is no reason why looking .. up
+ on a file couldn't return the directory it's contianed in
+ <pochu> I don't know the interfaces or the Hurd internals very well yet,
+ but it would look strange to me if you could do that
+ <marcusb> the hurd is strange
+ <pochu> it sounds like if you could `ls getcwd.c/..` to get
+ sysdeps/mach/hurd/ :-)
+ <marcusb> yep
+ <pochu> ok. interesting
+ <marcusb> you wouldn't find "ls" very strange, wouldn't you?
+ <pochu> I guess not if `ls` listed the contents of
+ <marcusb> there you go
+ <marcusb> or the other way round: would you be surprised if "cat somedir"
+ would work?
+ <pochu> I think so. if it did, what would it do?
+ <marcusb> originally, cat dir would list the directory content!
+ <marcusb> in the old unix times
+ <pochu> I was surprised the first time I typed `vi somedir` by accident
+ <marcusb> and some early BSDs
+ * pochu feels young :-)
+ <marcusb> he don't worry, I didn't see those times either
+ <marcusb> technically, files and directories are implemented in the same
+ way in the hurd, they both are objects implementing the fs.defs interface
+ <marcusb> which combines file and directory operations
+ <marcusb> of course, files and directories implement those functions
+ differently
+ <antrik> marcusb: do you know why this behavior (cat on directories) was
+ changed?
+## IRC, freenode, #hurd, 2013-03-07
+ * pinotree ponders about sending as RFC his patch for /proc/$pid/maps
+ <tschwinge> Including a scheme for providing the names of mapped files?
+ ;-D
+ <braunr> that would be really great indeed
+ <tschwinge> I have not yet researched how Linux does this. Perhaps store
+ the filename used for first opening a file as a string somewhere?
+ <pinotree> tschwinge: eh, indeed that's lacking in my patch
+ <braunr> i'm not sure we should aim at doing it the same way
+ <youpi> I was wondering about having interfaces for naming tasks, threads,
+ objects
+ <youpi> that'd be useful for debugging in general
+ <braunr> yes
+ <braunr> i don't think we need to take namespaces into account
+ <braunr> a simple name or path should be quite enough
+ <tschwinge> Agreed. "Just something!"
+ <tschwinge> So, a Java toString() method for ports.
+ <tschwinge> ;-)
+ <braunr> yes
+ <tschwinge> Oh, and could this also work recursively? The ext2fs instance
+ on /home asks its parent fs about its own path -- can it do that? (And
+ then cache that, most likely?) Would one get rooted filesnames that way?
+ <braunr> i really don't think we should link it to the VFS
+ <braunr> it should merely be a name for debugging
+ <youpi> yep, same for me
+ <youpi> I'd say it's the linker's task of just setting a sane name
+ <braunr> first, keeping it isolated prevents increasing complexity
+ <braunr> next, it doesn't reduce performance
+ <tschwinge> youpi: Linker?
+ <tschwinge> braunr: Ack.
+ <braunr> yes, ld is the one creating the mappings
+ <youpi> tschwinge: the one that loads libraries
+ <tschwinge> Ah, for /proc/*/maps, right. I've been thinking more globally.
+## task_get_name, task_set_name RPCs
+The following needs to be updated now that
+[[microkernel/mach/gnumach/interface/task_set_name]] has been implemented.
+[[!message-id ""]]
+## IRC, freenode, #hurd, 2013-05-10
+ <youpi> tschwinge's suggestion to put names on ports instead of tasks would
+ be useful too
+ <braunr> do you get task ports as easily as you get tasks in kdb ?
+ <youpi> there is task->itk_self & such
+ <youpi> or itk_space
+ <youpi> I don't remember which one is used by userspace
+ <braunr> i mean
+ <braunr> when you use the debugger, can you easily find its ports ?
+ <braunr> the task ports i mean
+ <braunr> or thread ports or whatever
+ <youpi> once you have a task, it's a matter of getting the itk_self port
+ <youpi> s/port/field member/
+ <braunr> so the debugger provides you with the addresses of the structs
+ <braunr> right ?
+ <youpi> yes, that's what we have already
+ <braunr> then ok
+ <braunr> bddebian: do that :p
+ <braunr> hehe
+ <youpi> see show all thread
+ <braunr> (haven't used kdb in a long time)
+ <bddebian> So, adding a name to ports like I did with tasks?
+ <braunr> remove what you did for tasks
+ <braunr> move it to ports
+ <braunr> it's very similar
+ <braunr> but hm
+ <braunr> i'm not sure where the RPC would be
+ <braunr> this RPC would exist for *all* ports
+ <braunr> or only for kernel objects if added to gnumach.defs
+ <youpi> it's just about moving the char array field to another structure
+ <youpi> and plugging that
+ <bddebian> But mach_task_self is a syscal, it looks like itk_self is just a
+ pointer to an ipc_port ?
+ <braunr> so ?
+ <braunr> you take that pointer and you get the port
+ <braunr> just like vm_map gets a struct vm_map from a task
+ <bddebian> So I am just adding ipc_port_name to the ipc_port struct in this
+ case?
+ <braunr> yes
+ <braunr> actually
+ <braunr> don't do anything just yet
+ <braunr> we need to sort a few details out first
+ <braunr> see bug-hurd
+## IRC, freenode, #hurd, 2013-12-05
+ <teythoon> braunr: no more room for vm_map_find_entry in 80220a40
+ <teythoon> 80220a40 <- is that a task ?
+ <braunr> or a vm_map, not sure
+ <braunr> probably a vm_map
+ <teythoon> hm
+ <teythoon> let's fix this kind of reporting
+ <braunr> :)
+ <teythoon> let one process register for kernel log messages
+ <teythoon> make a rich interface, say klog_thread and friends
+ <teythoon> a userspace process gets the port name, looks it up in proc,
+ logs nicely to syslog
+ <teythoon> if noone registered for this notifications, fall back to the old
+ reporting
+ <braunr> i tend to think using internal names is probably better
+ <teythoon> how would i use them to see wich process caused the issue ?
+ <braunr> you give the name of the task
+ <braunr> (which means tasks have names, yes)
+ <teythoon> ok
+ <braunr> the reason is that reporting is often used for debugging
+ <braunr> and debugging usually means there is a bug
+ <braunr> if the bug prevents from reporting, it's not very useful
+ <braunr> and we're talking about the kernel here, the low level stuff
+ <teythoon> incidentally, i got myself a stuck process
+ <teythoon> ah, got it killed
+ <teythoon> braunr: so you propose to add a task rpc to set a name ?
+ <braunr> i don't want to push such things
+ <braunr> which is why this hasn't been done until now
+ <braunr> but that's what i'd do in x15, yes
+ <teythoon> y not ?
+ <braunr> and instead of a process registered to gather kernel messages, i'd
+ use a dmesg-like interface, where the kernel manages its message buffer
+ itself
+ <braunr> i didn't feel the need to
+ <braunr> the tools i've had until now were sufficient
+ <braunr> don't forget you still need to fix mtab :p
+ <braunr> or is it done ?
+ <teythoon> i sometimes see tasks deallocating invalid ports
+ <teythoon> no
+ <teythoon> there is an un-acked patche series on the list
+ <braunr> ok
+ <teythoon> so, i want to identify which process caused it
+ <teythoon> is that possible right now ?
+ <braunr> not easily, no
+ <teythoon> so that's a valid use case
+ <braunr> it is
+ <teythoon> good
+ <teythoon> :)
+ <teythoon> so proc would register a string describing each task and mach
+ would use this for printing nicer messages ?
+ <braunr> for example, yes
+ <braunr> one problem with that approach is that it doesn't fit well with
+ subhurds
+ <teythoon> *bingbingbing
+ <braunr> but i personally wouldn't care much, they're kernel messages
+ <braunr> in the future, we could make mach more a hypervisor, and register
+ names for each domains
+ <teythoon> yet unanswered proposal about hierachical proc servers on the
+ list...
+ <teythoon> that'd also fix subhurds, so that the parents processes won't
+ appear in the subhurd
+ <teythoon> making it sandboxier
+ <teythoon> and killall5 couldn't slaughter the host system if the subhurd
+ shuts down with sysvinit
+## IRC, freenode, #hurd, 2014-01-20
+ <teythoon> i wonder if it would not be best to add a description to mach
+ tasks
+ <braunr> i think it would
+ <teythoon> to aid fixing these kind of issues
+ <braunr> in x15, i actually add descriptions (names) to all kernel objects
+ <teythoon> that's probably a good idea, yes
+ <braunr> well, not all, but many
+## IRC, OFTC, #debian-hurd, 2014-02-05
+ <teythoon> youpi: about that patch implementing task_set_name, may i merge
+ the amended version ?
+ <youpi> yes
+# IRC, freenode, #hurd, 2011-07-13
+A related issue:
+ <braunr> rbraun@nordrassil:~$ vminfo $$ | wc -l
+ <braunr> 1039
+ <braunr> any idea why a shell would consume more than 1039 map entries ?
+ <braunr> (well, not more actually)
+ <braunr> even the kernel and ext2fs have around 100
+ <braunr> (the kernel has actually only 23, which is very good and expected)
+ <tschwinge> braunr: I agree that having some sort of debugging information
+ for memory objects et al. would be quite hand. To see where they're
+ coming from, etc.
+ <braunr> tschwinge: this would require naming objects at the mach level
+ <braunr> e.g. when creating an object
+ <braunr> giving it the path of a file for example
+ <tschwinge> braunr: I have recently seen something (due to youpi fixing a
+ bug) that bash is doing its own memory management. Perhaps all these are
+ such regions?
+ <tschwinge> braunr: For example, yes.
+ <braunr> what ?
+ <braunr> ?!
+ <tschwinge> braunr:
+ <braunr> i see
+Also see email thread starting at [[!message-id
+Justus: Once [[!message-id desc="these patches"
+""]] are
+merged, there will be a way to map from ports to file names, at least for
+libdiskfs and libnetfs, one would only have to make this information available