aboutsummaryrefslogtreecommitdiff
path: root/open_issues/file_locking.mdwn
diff options
context:
space:
mode:
authorhttps://me.yahoo.com/a/g3Ccalpj0NhN566pHbUl6i9QF0QEkrhlfPM-#b1c14 <diana@web>2015-02-16 20:08:03 +0100
committerGNU Hurd web pages engine <web-hurd@gnu.org>2015-02-16 20:08:03 +0100
commit95878586ec7611791f4001a4ee17abf943fae3c1 (patch)
tree847cf658ab3c3208a296202194b16a6550b243cf /open_issues/file_locking.mdwn
parent8063426bf7848411b0ef3626d57be8cb4826715e (diff)
downloadweb-95878586ec7611791f4001a4ee17abf943fae3c1.tar.gz
web-95878586ec7611791f4001a4ee17abf943fae3c1.tar.bz2
web-95878586ec7611791f4001a4ee17abf943fae3c1.zip
rename open_issues.mdwn to service_solahart_jakarta_selatan__082122541663.mdwn
Diffstat (limited to 'open_issues/file_locking.mdwn')
-rw-r--r--open_issues/file_locking.mdwn98
1 files changed, 0 insertions, 98 deletions
diff --git a/open_issues/file_locking.mdwn b/open_issues/file_locking.mdwn
deleted file mode 100644
index 7dfbdb94..00000000
--- a/open_issues/file_locking.mdwn
+++ /dev/null
@@ -1,98 +0,0 @@
-[[!meta copyright="Copyright © 2010, 2011, 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_hurd open_issue_glibc]]
-
-[[!toc]]
-
-
-# Google Summer of Code Project Idea
-
-[[community/gsoc/project_ideas/File_Locking]].
-
-
-# visudo
-
-[[visudo]].
-
-
-# Existing Work
-
-[[!GNU_Savannah_patch 332]].
-
-
-# IRC, freenode, #hurd, 2010-12-31
-
- <pinotree> youpi: i found the issue with python-apt
- <pinotree> s/with/of/
- <youpi> good!
- <pinotree> lock file issue, though :/
- <youpi> :/
- <pinotree> this is the sample test case, derived from apt's code:
- http://paste.debian.net/103536/
- <pinotree> basically, it seems asking for a file lock in the same process
- where there's already such lock on the file, fails
- <pinotree> youpi: ↑
- <youpi> uh, posix doesn't even define some nesting
- <pinotree> it seems it just talks about concurrency with other processes
- <youpi> posix tells more about it later
- <youpi> saying that if a lock already exists, then it is replaced by the
- new
- <youpi> (when inside the same process)
- <pinotree> yay, found a bug in hurd :p
- <youpi> well, actually it's known
- <youpi> i.e. setlk is completely bogus, based on flock
- <youpi> and flock doesn't have the same semantic in that regard
- <youpi> so we can't fix it without really implementing setlk
- <pinotree> the XXX comment in glibc/sysdeps/mach/hurd/fcntl.c, by chance?
- :)
- <youpi> of course :)
- <pinotree> youpi: hm, flock's man page says:
- <pinotree> "A process may only hold one type of lock (shared or exclusive)
- on a file. Subsequent flock() calls on an already locked file will
- convert an existing lock to the new lock mode."
- <pinotree> so a new lock in the same process over the original lock should
- replace the old one?
- <youpi> uh, that's not what I had seen
- <pinotree> http://linux.die.net/man/2/flock
- <youpi> An attempt to lock the file using one of these file descrip-
- <youpi> tors may be denied by a lock that the calling process
- has already
- <youpi> placed via another descriptor.
- <youpi> so it's really not that easy
- <pinotree> that's in case of trying to create a lock on a file with a
- different fd than the existing lock
- <youpi> that's what your testcase does
- <pinotree> which, hm, is python-apt's case
- <youpi> that being said, the sentence I pasted does not seem to appear in
- posix
- <pinotree> flock() does not seem posix
- <youpi> it may have been the behavior of Linux at some point in the past
- <youpi> it's not , but F_SETLK is
- <youpi> and in linux world, flock <=> F_SETLK, iirc
- <youpi> in glibc world, even
- <youpi> (just checked it, see sysdeps/posix/flock.c
- <youpi> pinotree: I guess your testcase works on Linux?
- <pinotree> which means we should get a proper F_SETLK working, and then
- just use this flock version (instead of the custom one), no?
- <pinotree> yes, it works on linux (and on kfreebsd, see that python-apt
- builds)
- <youpi> no, I mean our flock() should probably be happy with locking part
- of a file several times
- <youpi> (that is, hurd's file_lock() RPC)
- <youpi> ah, no, on Linux flock is its own system call
- <youpi> (which is independant from lockf from the locking point of view,
- iirc)
-
-
-# 2014-03-11
-
-[[!message-id "1394523876.28244.11.camel@workhorse-peter-baumgarten-com"]].