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diff --git a/open_issues/translate_fd_or_port_to_file_name.mdwn b/open_issues/translate_fd_or_port_to_file_name.mdwn new file mode 100644 index 00000000..252bc049 --- /dev/null +++ b/open_issues/translate_fd_or_port_to_file_name.mdwn @@ -0,0 +1,280 @@ +[[!meta copyright="Copyright © 2010, 2011, 2013, 2014 Free Software Foundation, +Inc."]] + +[[!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 +License|/fdl]]."]]"""]] + +[[!tag open_issue_glibc open_issue_hurd]] + +[[!toc]] + + +# 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 foo.zip/.." very strange, wouldn't you? + <pochu> I guess not if `ls foo.zip` listed the contents of foo.zip + <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 "518AA5B0.6030409@verizon.net"]] + + +## 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: + http://lists.gnu.org/archive/html/bug-bash/2011-04/msg00097.html + <braunr> i see + +Also see email thread starting at [[!message-id +"20110714082216.GA8335@sceen.net"]]. + +Justus: Once [[!message-id desc="these patches" +"1375178364-19917-4-git-send-email-4winter@informatik.uni-hamburg.de"]] 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 +somehow. |