March 2011 - Darwin-dev - lists.apple.com

C++ dylib problem
by Robert Bielik 11 Mar '11

11 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; sv-SE; rv:1.9.2.15) Gecko/20110303 Lightning/1.0b2 Thunderbird/3.1.9 Hi all, I have an application that I build using Xcode 3.2.2 with the 10.6 SDK with deployment target set to 10.4. The application works fine (tested) on 10.4.11 and 10.6.3. BUT there is a machine with 10.5.8 where it just refuses, and it is a dylib problem with libstdc++.6.dylib: Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000002, 0x0000000000000000 Crashed Thread: 0 Dyld Error Message: Symbol not found: __ZSt16__ostream_insertIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_PKS3_i Referenced from: /Applications/......... Expected in: /usr/lib/libstdc++.6.dylib Output of otool -L on that machine is: /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation (compatibility version 300.0.0, current version 751.0.0) /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit (compatibility version 45.0.0, current version 1038.0.0) /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit (compatibility version 1.0.0, current version 275.0.0) /System/Library/Frameworks/CoreAudio.framework/Versions/A/CoreAudio (compatibility version 1.0.0, current version 1.0.0) /System/Library/Frameworks/AGL.framework/Versions/A/AGL (compatibility version 1.0.0, current version 1.0.0) /System/Library/Frameworks/CoreMIDI.framework/Versions/A/CoreMIDI (compatibility version 1.0.0, current version 49.0.0) /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL (compatibility version 1.0.0, current version 1.0.0) /System/Library/Frameworks/DiscRecording.framework/Versions/A/DiscRecording (compatibility version 1.0.0, current version 1.0.0) /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon (compatibility version 2.0.0, current version 152.0.0) /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit (compatibility version 1.0.0, current version 531.9.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 123.0.0) /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0) /usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 438.0.0) /usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 227.0.0) /System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices (compatibility version 1.0.0, current version 44.0.0) /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 550.0.0) /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices (compatibility version 1.0.0, current version 38.0.0) I'm clueless. Any ideas ? TIA /Rob _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: chroot and setuid binaries
by Jay Buffington 09 Mar '11

09 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=9tgdAbY3NlUZClcZVVEHweJzmiwjMPcoGmImmAi5Q8c=; b=D+1ywGA/rPmWzsnYHdWB4DvdM+wo9NTin7If/1OefAAcGHTlRfPcszOShtdSXAtZwc kDxRBVXDvcF/rZqapWcSthIMVzvfC3g1BcX+V2/2bd+SHunfXyQJo0dQqid8yU5lA3CW ZA95TxpOZo8gUige1FH84vsqR4IWSXntsQJtg= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=pCgnxDqRji1zA0g9aq9KhFs9ev/nZeAu7fNDBAX5QXXWOp51q0b/naH1r18PPBhwDe hXUyeHFLNtJhlXLEZmNzokf5GvnnuWDGviXgfqnkrmEM3X5l+ILjHSUaIOtxbUEdxTlF lt7zRZMVw3ovAdS1+jJz7iVyrgCWlXtESYJB4= On Wed, Feb 23, 2011 at 10:03 AM, Axel Luttgens <luttgens(a)fusl.ac.be> wrote: > Moreover, isn't the volume mounted nosuid by default? This was exactly my problem. Thanks, Axel. The mount command showed this in it's output: /dev/disk1s2 on /Volumes/untitled (hfs, local, nodev, nosuid, mounted by jaybuff) I was able to mount it without the nosuid option and everything worked: $ hdiutil attach -owners on -nomount ~/images/mac_os_x-10.5.7.sparseimage $ sudo mkdir /Volumes/mac_os_x-10.5.7 $ sudo mount -t hfs -o nodev /dev/disk2s2 /Volumes/mac_os_x-10.5.7 $ sudo /sbin/mount -t devfs devfs /Volumes/mac_os_x-10.5.7/dev $ sudo /sbin/mount -t fdesc -o union stdin /Volumes/mac_os_x-10.5.7/dev/ $ sudo bindfs /Users/jaybuff /Volumes/mac_os_x-10.5.7/Users/jaybuff $ sudo chroot /Volumes/mac_os_x-10.5.7/ bash bash-3.2# su - jaybuff $ ./euid euid: 0 Thanks! Jay _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: pthread - system() blocking
by Greg Parker 01 Mar '11

01 Mar '11

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Re: pthread - system() blocking
by Chris Suter 01 Mar '11

01 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hi Greg, On Tue, Mar 1, 2011 at 8:47 PM, Greg Parker <gparker(a)apple.com> wrote: > No. > The problem is that there's no "close all but these" file action for > posix_spawn(). There's no safe way for posix_spawn() to create a child > process with all descriptors closed except a known set like stdin/out/err. > You cannot safely use posix_spawn_file_actions_addclose() for every open > descriptor in the parent, because other threads in the parent may be > concurrently opening and closing those descriptors between the time you set > up the file actions and the time you call posix_spawn(). But what if you added a close action for all possible file descriptors except for stdin, stdout & stderr? i.e. looped over all 1024 (or however many) file descriptors except for those three? And how exactly would you close file descriptors between the fork and exec? How do you know what file descriptors to close? -- Chris _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: pthread - system() blocking
by Greg Parker 01 Mar '11

01 Mar '11

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Re: pthread - system() blocking
by Chris Suter 01 Mar '11

01 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Tue, Mar 1, 2011 at 7:52 PM, Tilghman Lesher <tilghman(a)meg.abyt.es> wrote: > I'd stick with the fork/exec, so you can deal with these issues directly. But can't you do with posix_spawn_file_actions whatever you'd want to do with fork/exec? -- Chris _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: pthread - system() blocking
by Tilghman Lesher 01 Mar '11

01 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meg.abyt.es; s=google; h=domainkey-signature:from:to:subject:date:user-agent:references :in-reply-to:reply-by:x-message:mime-version:content-type :content-transfer-encoding:message-id; bh=bhSZbhgAHYxw0DwecIbzmEgt1JKKS1AvCgcJ11AJSA0=; b=Kc9E6ls7yy7MPVwbDnBOLSl8QLhX1i2mI6Zzqyieal5M3pnhTCS0AHWFQwS0e/q/wq WBT8dUYPJT9+X3Emp2SNZffqet411CsvlFW6aRRnJhihnzNanra6BUYzwUMCKHoIUYAy wA9/nB2na0mSAVs7y8gl+sEq/k0yeLhrfFqOc= Domainkey-signature: a=rsa-sha1; c=nofws; d=meg.abyt.es; s=google; h=from:to:subject:date:user-agent:references:in-reply-to:reply-by :x-message:mime-version:content-type:content-transfer-encoding :message-id; b=X6OaV7VdXrMGt3sn1jh1juzE/ZoYAqQTHp5cDKHTBkGspEjqUmHT0LfVmEhCm7p/TH k/jZsLI+kayBLLIwaEP4QeazX6fj9q6XBOIEuAiDUoFWmNtwLeXnvww5iOq43YqNNofF UzvcdSyvzp7maLscMJeWnedu7SO6kg69QR1UI= Reply-by: Wed, 19 Jan 2011 16:20:00 -0600 User-agent: KMail/1.13.5 (Linux/2.6.32-29-server; KDE/4.4.5; x86_64; ; ) On Tuesday 01 March 2011 02:09:18 Jean-Daniel Dupas wrote: > Le 1 mars 2011 à 00:29, Jason Coco a écrit : > > On Feb 28, 2011, at 18:20 , Stephen J. Butler wrote: > >> On Mon, Feb 28, 2011 at 5:13 PM, Mark E. Armstrong > >> > >> <Mark.Armstrong(a)soleratec.com> wrote: > >>> In a pthread application, I need to call system() to execute an > >>> external program. When system() is called in a non-main thread, > >>> any other calls to system() are blocked until the previous call has > >>> returned. How do we work around the blocking? > >> > >> Are you sure you aren't just seeing the effects of output buffering? > >> That would be my first guess at what's happening... not that system() > >> is being serialized. > >> > >> But if that IS actually the case, you can always fork/exec yourself. > > > > The system() call definitely blocks and is definitely serial. It will > > also override your signal handling for SIGINT, SIGQUIT and SIGCHLD. > > It's really just a simple convenience call for doing very simple > > shell execs. If you want to run things in parallel, you'll have to > > fork/exec > > Actually, the recommended way is to spawn a process (using posix_spawn) > instead of using fork/exec yourself. I think that would actually be race condition prone, because in a threaded application, many calls for opening file descriptors do not support setting the FD_CLOEXEC flag in the initial system call. Since a second system call is needed to add the flag, there's an inherent race between those two separate calls and a call to posix_spawn. This is only a problem, of course, in multi-threaded applications. Secondary to that is the issue of whether the process being spawned is a short-lived process; if it is, it may be acceptable for some file descriptors to remain open in the new process. However, a long-lived process could certainly prevent a particular closure of, for example, a pipe from sending the expected signal to the remote end. I'd stick with the fork/exec, so you can deal with these issues directly. -- Tilghman _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: pthread - system() blocking
by Jean-Daniel Dupas 01 Mar '11

01 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Le 1 mars 2011 à 00:29, Jason Coco a écrit : > > On Feb 28, 2011, at 18:20 , Stephen J. Butler wrote: > >> On Mon, Feb 28, 2011 at 5:13 PM, Mark E. Armstrong >> <Mark.Armstrong(a)soleratec.com> wrote: >>> In a pthread application, I need to call system() to execute an external >>> program. When system() is called in a non-main thread, any other calls to >>> system() are blocked until the previous call has returned. How do we work >>> around the blocking? >> >> Are you sure you aren't just seeing the effects of output buffering? >> That would be my first guess at what's happening... not that system() >> is being serialized. >> >> But if that IS actually the case, you can always fork/exec yourself. > > The system() call definitely blocks and is definitely serial. It will also override your signal handling for SIGINT, SIGQUIT and SIGCHLD. > It's really just a simple convenience call for doing very simple shell execs. If you want to run things in parallel, you'll have to fork/exec Actually, the recommended way is to spawn a process (using posix_spawn) instead of using fork/exec yourself. -- Jean-Daniel _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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