Re: [X2Go-Dev] [PATCH] Re: x2godesktopsharing SIGSEV - how to compile with debugging info?
V Sun, 12 Feb 2012 22:48:02 +0100 Milan Knížek <knizek.confy@gmail.com> napsáno:
Hello,
I get Segmentation fault when I right-click on x2godesktopsharing icon in the system tray and choose "Activate Desktop Sharing". (Arch Linux.)
The segfault was due to non-existent "x2godesktopsharing" group in the system.
This involves two matters:
x Arch Linux does not allow for group names longer then 16 characters.
x x2godesktopsharing should check for existence of the group and quit nicely otherwise.
Since I am not a coder, I was able to solve only the first issue - patches are attached. (The debian postinst script should probably handle the original group name as well - e.g. move the members to the new group.)
It would be nice if it is accepted upstream, since a similar limitation might also exist on other *nix systems.
Regards, Milan
-- http://www.milan-knizek.net/ About linux and photography (Czech only) O linuxu a fotografování
Hi All,
On Mo 13 Feb 2012 22:10:26 CET Milan Knížek wrote:
V Sun, 12 Feb 2012 22:48:02 +0100 Milan Knížek <knizek.confy@gmail.com> napsáno:
Hello,
I get Segmentation fault when I right-click on x2godesktopsharing icon in the system tray and choose "Activate Desktop Sharing". (Arch Linux.)
The segfault was due to non-existent "x2godesktopsharing" group in the system.
This involves two matters:
x Arch Linux does not allow for group names longer then 16 characters.
x x2godesktopsharing should check for existence of the group and quit nicely otherwise.
Since I am not a coder, I was able to solve only the first issue - patches are attached. (The debian postinst script should probably handle the original group name as well - e.g. move the members to the new group.)
It would be nice if it is accepted upstream, since a similar limitation might also exist on other *nix systems.
I need some feedback from the other devs how to handle this. We/I
changed from group x2godesktopshare to x2godesktopsharing more or less
recently, but was not aware of gid-lenght limitations in POSIX.
What do other devs think of reverting the group name change?
Mike
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On Saturday 2012-02-18 00:55, Mike Gabriel wrote:
I get Segmentation fault when I right-click on x2godesktopsharing icon in the system tray and choose "Activate Desktop Sharing". (Arch Linux.)
The segfault was due to non-existent "x2godesktopsharing" group in the system.
This involves two matters:
x Arch Linux does not allow for group names longer then 16 characters.
x x2godesktopsharing should check for existence of the group and quit nicely otherwise.
I need some feedback from the other devs how to handle this. We/I changed from group x2godesktopshare to x2godesktopsharing more or less recently, but was not aware of gid-lenght limitations in POSIX.
What do other devs think of reverting the group name change?
I do not see any group name length limit either, however,
(a) there is a limit as to what a user can/want to take. While
tabcompletion probably gets you out most of the time, nobody really
wants e.g. /home/Karl\ Theodor\ Maria\ Nikolaus\ Johann\ Jacob
Philipp\ Franz\ Joseph\ Sylvester\ Freiherr\ von\ und\ zu\ Guttenberg
(21st century, though past-time, German politician serving for this
example).
(b) not defined by POSIX, but there is an actual sanity limit. A username length about PATH_MAX chars long becomes problematic to be used in a path, e.g. when attempting to use for /home :)
The 16 character limit in Arch is just like the 80 character "limit" in coding. But actually, it is not a limit, but a wellness target: it may be exceeded if there is a justification. In contrast, historic UNIX usernames of 8 chars - /that/ was a limit.
Was there a reason to put users through a name change the first time? (Note that such changes may not necessarily be automated, e.g. when users relocate the group into LDAP)
V Sat, 18 Feb 2012 09:00:30 +0100 (CET) Jan Engelhardt <jengelh@medozas.de> napsáno:
I do not see any group name length limit either, however,
(a) there is a limit as to what a user can/want to take. While tabcompletion probably gets you out most of the time, nobody really wants e.g. /home/Karl\ Theodor\ Maria\ Nikolaus\ Johann\ Jacob
Philipp\ Franz\ Joseph\ Sylvester\ Freiherr\ von\ und\ zu\ Guttenberg (21st century, though past-time, German politician serving for this example).(b) not defined by POSIX, but there is an actual sanity limit. A username length about PATH_MAX chars long becomes problematic to be used in a path, e.g. when attempting to use for /home :)
The 16 character limit in Arch is just like the 80 character "limit" in coding. But actually, it is not a limit, but a wellness target: it may be exceeded if there is a justification. In contrast, historic UNIX usernames of 8 chars - /that/ was a limit.
This seems to be a compilation-time configure option GROUP_NAME_MAX_LENGTH...
On Debian (I looked at Knoppix actually), the limit is relaxed a bit: 32 chars.
It can be handled as a distro specific patch, although it complicates portability.
Regards, Milan
http://www.milan-knizek.net/ About linux and photography (Czech only) O linuxu a fotografování
On Saturday 2012-02-18 10:02, Milan Knížek wrote:
The 16 character limit in Arch is just like the 80 character "limit" in coding. But actually, it is not a limit, but a wellness target: it may be exceeded if there is a justification. In contrast, historic UNIX usernames of 8 chars - /that/ was a limit.
This seems to be a compilation-time configure option GROUP_NAME_MAX_LENGTH...
POSIX does say something about users in section
- 3.425 User ID
- 3.426 User Name
- 3.276 Portable Filename Character Set http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_...
Everything else should therefore be self-inflicted distro limits. :)
-
Jan Engelhardt -
Mike Gabriel -
Milan Knížek