Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
On Mar 9 19:08, Sjors Gielen wrote: > I think I checked how Cygwin implements fork() a while ago, can't really > remember though. But on a fork(), do processes inherit all information > on dll's, et cetera? Or do they reload the dll and re-check the > addresses of entry points and all? Very basically, the executable is started again via CreateProcess, then Cygwin copies the parent's data segments into the child. The important faxct here is that the actual load process of the child is done by the Windows loader. If you changed the Cygwin DLL in the meantime, the new process will load the new Cygwin DLL, not the old one. From there it goes downhill because the data layout of the new DLL is different from the layout in the old DLL loaded with the parent process. > I *think* this cygfoo1_2_3.dll system does not work with the Cygwin dll > itself, because that all still happens completely outside of Cygwin > scope Yes. This happens because we're using Windows API and thus Windows loader to load processes. The Windows API simply hasn't been designed to fork. That's why Cygwin has to do all the tricky and not very performant stuff before and after loading a process. Actually the native NT API is capable to fork a process and that's used, for instance, in Interix. However, Interix is its entire self-contained POSIX subsystem, distinct from Windows, while Cygwin processes are running inside of the Windows subsystem. Unfortunately important parts of the API used to attach a new process to the Windows subsystem are not documented. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
Christopher Faylor schreef: Right. And that has been the main reason why writing an installer which uses Cygwin is problematic. I've been using the "rename the dll or executable" technique for about ten years to install a newly-compiled version of cygwin1.dll on a system with a running version of cygwin. However, this hoses any running processes and it even makes running any cygwin processes flaky until all processes which use the old DLL have been shut down. cgf You're right. Any testing I've done until now regarding replacing files, did include replacing the Cygwin DLL, but it didn't include replacing the Cygwin DLL with a *different version* of the DLL. I think I checked how Cygwin implements fork() a while ago, can't really remember though. But on a fork(), do processes inherit all information on dll's, et cetera? Or do they reload the dll and re-check the addresses of entry points and all? Something I'm wondering about: When you build something against libfoo.so on Linux, usually you actually link against libfoo.1.2.3 because of the symlinks. I've seen cygfoo1_2_3.dll if I remember correctly - what about never having to replace dlls? This leaves the problem of replacing a Cygwin dll, but this is the only "special" DLL I think. Maybe there should be some kind of background daemon that's fired up when cygwin1.dll needs to be replaced. It then just puts itself in the systray, and when hovered it just says "Hey, maybe you want to reboot sometime soon to have me reload your Cygwin dll..." Then when all Cygwin processes are stopped, or the system reboots (which is the same), the dll is automatically replaced. I *think* this cygfoo1_2_3.dll system does not work with the Cygwin dll itself, because that all still happens completely outside of Cygwin scope, so no linking cygwin1.dll to anything. I'm not at all an expert on these matters, though. Sjors -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
On Mon, Mar 09, 2009 at 11:21:52AM +0100, Corinna Vinschen wrote: >On Mar 9 09:55, Andy Koppe wrote: >> Spiro Trikaliotis: >> > You can replace a running exe (or dll) by doing the following: >> > >> > 1. rename the .DLL or .EXE >> >> Are you sure that's possible? I'd expect Windows to complain loudly at >> that point. > >You can in theory, but that won't work reliably for subsequent Cygwin >processes. If you replace a running processes' executable with a new >release, and if that process is one of the forking kind, every >subsequent call to fork() will break. If you replace the Cygwin DLL >with a new release on the fly, then *any* subsequent fork() will almost >surely break. Right. And that has been the main reason why writing an installer which uses Cygwin is problematic. I've been using the "rename the dll or executable" technique for about ten years to install a newly-compiled version of cygwin1.dll on a system with a running version of cygwin. However, this hoses any running processes and it even makes running any cygwin processes flaky until all processes which use the old DLL have been shut down. cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
On Mar 9 10:18, Marco Atzeri wrote: > --- Lun 9/3/09, Andy Koppe ha scritto: > > Are you sure that's possible? I'd expect Windows to > > complain loudly at > > that point. > > [...] > I also used that trick to replace cyglsa.dll installing > snapshots but cyglsa.dll was not in use at that time. It's safe to do for cyglsa.dll. Windows accesses this DLL by handle and the replacement is only used after a reboot. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
On Mar 9 09:55, Andy Koppe wrote: > Spiro Trikaliotis: > > You can replace a running exe (or dll) by doing the following: > > > > 1. rename the .DLL or .EXE > > Are you sure that's possible? I'd expect Windows to complain loudly at > that point. You can in theory, but that won't work reliably for subsequent Cygwin processes. If you replace a running processes' executable with a new release, and if that process is one of the forking kind, every subsequent call to fork() will break. If you replace the Cygwin DLL with a new release on the fly, then *any* subsequent fork() will almost surely break. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
--- Lun 9/3/09, Andy Koppe ha scritto: > Da: Andy Koppe > Oggetto: Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck > typo in both manpage and --help) > A: cygwin@cygwin.com > Data: Lunedì 9 marzo 2009, 10:55 > Spiro Trikaliotis: > > You can replace a running exe (or dll) by doing the > following: > > > > 1. rename the .DLL or .EXE > > Are you sure that's possible? I'd expect Windows to > complain loudly at > that point. > > Andy > It is not feasible for cygwin1.dll, you can change the name and M$ will not complain but any following action will crash for a program based on cygwin1.dll. $ mv cygwin1.dll cygwin1.dll_test $ ls 3 [main] bash 2660 fork: child -1 - died waiting for longjmp before initialization, retry 10, exit code 0xC135, errno 11 bash: fork: Resource temporarily unavailable I also used that trick to replace cyglsa.dll installing snapshots but cyglsa.dll was not in use at that time. Regards Marco __ Do You Yahoo!? Poco spazio e tanto spam? Yahoo! Mail ti protegge dallo spam e ti da tanto spazio gratuito per i tuoi file e i messaggi http://mail.yahoo.it -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
Spiro Trikaliotis: > You can replace a running exe (or dll) by doing the following: > > 1. rename the .DLL or .EXE Are you sure that's possible? I'd expect Windows to complain loudly at that point. Andy -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
Hello, * On Sun, Mar 08, 2009 at 09:45:39PM -0400 Christopher Faylor wrote: > On Mon, Mar 09, 2009 at 12:42:31AM +0100, Sjors Gielen wrote: > > (Since 1.7 already fixes the problem of installing running programs, > > Color me dubious. How did you solve the problem of installing cygwin over > a running version of cygwin? You can replace a running exe (or dll) by doing the following: 1. rename the .DLL or .EXE 2. put the new .DLL or .EXE into place Once the program holding the .DLL or .EXE quits, you can remove the renamed versions. This can be done on the next boot, for example. Best regards, Spiro. -- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/ -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
On Mon, Mar 09, 2009 at 12:42:31AM +0100, Sjors Gielen wrote: > Christopher Faylor schreef: >>> setup.exe and cygcheck are very nice but was wondering if the idea of >>> using >>> yum and rpm was ever tossed around? >> Yes, it has been discussed many times. There are big barriers to >> getting these working, mainly due to problems installing already-running >> programs. >> cgf > > Hey Christopher, > > I've succesfully ported dpkg. In a few weeks time, I'll start working on my > Debian Cygwin project again, I'm currently busy with other things - but > maybe you could take a look at my dpkg changes and see if you can make a > Cygwin-dpkg which is compatible with cygcheck and setup.exe. Dpkg is very > easy to use, as is apt-get which I was busy porting before I stopped > temporarily. Sorry but I don't see us moving to dpkg. If we were going to use anything it would probably be rpm. Cygwin is owned by Red Hat and hosted on a Red Hat sponsored system after all. > (Since 1.7 already fixes the problem of installing running programs, Color me dubious. How did you solve the problem of installing cygwin over a running version of cygwin? cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Replacing setup.exe and cygcheck with dpkg (Was: Re: cygcheck typo in both manpage and --help)
Christopher Faylor schreef: setup.exe and cygcheck are very nice but was wondering if the idea of using yum and rpm was ever tossed around? Yes, it has been discussed many times. There are big barriers to getting these working, mainly due to problems installing already-running programs. cgf Hey Christopher, I've succesfully ported dpkg. In a few weeks time, I'll start working on my Debian Cygwin project again, I'm currently busy with other things - but maybe you could take a look at my dpkg changes and see if you can make a Cygwin-dpkg which is compatible with cygcheck and setup.exe. Dpkg is very easy to use, as is apt-get which I was busy porting before I stopped temporarily. (Since 1.7 already fixes the problem of installing running programs, there are only two important changes: multiple slashes at the beginning of a path are mapped to one, and when installing a new binary dpkg uses vfork() instead of fork() for the one corner case where dpkg re-installs itself.) If you want them, I'll upload the patches to the subversion repository of the project as soon as I can. They are currently sleeping on my disk until the project gets far enough to release some binaries and sources. Sjors -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
