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

Re: pthread - system() blocking
by Jason Coco 28 Feb '11

28 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com 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 and then wait on the children for exit information (which you can do using any of kqueue(), select() or dispatch sources very easily and without blocking). _______________________________________________ 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 Stephen J. Butler 28 Feb '11

28 Feb '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 :content-transfer-encoding; bh=2ui473d9zdokgjRE5E+J/VUklY5l+uvXMTfr0KN6+4w=; b=l8ENvaNB9vSgcd8WWTn1WpKomEwkR1iitgVFwnISHSvhMfZiG9G/YPacAb/5XIUXoI QgJWMn4lXO6l0VdkyQMbt2rp/rl7R9yI1mwuoV58F2OmCmTu0C4Z96s1aBTndCAdYK2n MQWibU8PD8XYwGidnaRRmZIcXiynzLbVN2dXk= 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:content-transfer-encoding; b=QK5rQW7PSOEB+vfntFMpWFKSn8FGQ+wpIV6RcJgTegEZt6WCbUjiC/UwwQJA27zNN2 z95MRSyRwev8tO5e6dZaJq4rkSFrAridiFxdk04Y+X2OMv/ArGIiJA3qR7BEXFOjzKoU TOkkTNIeA8gReHUEzZJHHGBLcgyJwM4KjS2ws= 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. _______________________________________________ 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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pthread - system() blocking
by Mark E. Armstrong 28 Feb '11

28 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Thread-index: AcvXnRDbxcPajybGRImMkS0pGtv8tg== Thread-topic: pthread - system() blocking _______________________________________________ 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 Mike 23 Feb '11

23 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 http://developer.apple.com/library/mac/#samplecode/MoreAppleEvents/Listings… In particular, read the MoreSecurity .h & .c files' comments. http://www.michael-amorose.com/books/index.htm Hi all, I am building a chroot management tool[1] for developers. It works under linux and I'm in the process of adding Mac support. I've ran into a couple of issues and could use a hand. I'm mounting a sparseimage and chroot'ing into it. When I do this ls tells me that binaries such as sudo and ping correctly have the setuid bit set and are owned by root. However, when I execute these binaries, their call to geteuid returns the user id rather than 0 (confirmed with dtruss[2]). The below commands, all executed on my macbook pro running 10.5.7, demonstrate this: # build the image that i'll chroot into export image_name=mac_os_x-10.5.7 export image_file=~/images/$image_name.sparseimage mkdir ~/images hdiutil create -type SPARSE -fs HFS+ -volname $image_name -size 5g -attach \ $image_file for P in BaseSystem Essentials BSD X11User; do \ sudo installer -target /Volumes/$image_name -pkg \ '/Volumes/Mac OS X Install DVD/System/Installation/Packages/'$P.pkg;\ done # mount some important directories for the chroot sudo mount -t devfs devfs /Volumes/$image_name/dev sudo mount -t fdesc -o union stdin /Volumes/mac_os_x-10.5.7/dev sudo mkdir -p /Volumes/$image_name/Users/jaybuff sudo bindfs /Users/jaybuff /Volumes/$image_name/Users/jaybuff $ # show that geteuid correctly returns 0 outside of the chroot: $ cat euid.c #include<stdio.h> main() { printf("euid: %i\n", geteuid()); } $ gcc euid.c -o euid $ chmod 04755 euid $ sudo chown root:wheel euid $ ./euid euid: 0 $ # copy it into the chroot $ cp euid /Volumes/mac_os_x-10.5.7/tmp/euid $ sudo chroot /Volumes/mac_os_x-10.5.7 bash bash-3.2# ls -la /tmp/euid -rwsr-xr-x 1 root wheel 12612 Feb 22 19:23 /tmp/euid bash-3.2# su - jaybuff $ /tmp/euid euid: 37964 $ id uid=37964(jaybuff) gid=100(users) groups=100(users),101(com.apple.sharepoint.group.1),98(_lpadmin),102(com.apple.sharepoint.group.2),80(admin),20(staff) Why does geteuid return 0 for a setuid binary outside of a chroot, but not when executed inside a chroot? Thanks, Jay [1] http://getjoot.org [2] http://www.brendangregg.com/dtrace.html _______________________________________________ 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/junklists%40michael-amoro… This email sent to junklists(a)michael-amorose.com _______________________________________________ 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… You may also want to take a look at Quinn's source code comments from MIB which discuss uid and effective uid in setuid helper tools on OS X: I've got a little booklet on OS X helper tools here, but I don't think it addresses your specific problem: On 2/23/11 9:07 AM, Jay Buffington wrote: This email sent to site_archiver(a)lists.apple.com

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Re: chroot and setuid binaries
by Axel Luttgens 23 Feb '11

23 Feb '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:sender:subject:mime-version:content-type:from :in-reply-to:date:reply-to:content-transfer-encoding:message-id :references:to:x-mailer; bh=wjVdEUd0BICKwf6CZ51C+f9iFVulM7ujpOMLEXf01Yo=; b=l3W+w7hoJIf5MCM2Nz4WvSiJ3Mj8f2LHteKzXnOFVBFKTpCNdrExlI8MufbyyCtg5R Wl6iryh8lgNZ+V3skSSpEJZSQ/C2/3Tx2Yb1OogxOhBpAhCiMJp8MLANVfT4Pd/ZGh4u v8+duMx7Lrj3WUF1zqJ6pVIAnpAqXC2Ii7prU= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:subject:mime-version:content-type:from:in-reply-to:date :reply-to:content-transfer-encoding:message-id:references:to :x-mailer; b=IceCb9GftDiKXfuIDMu+blExGcehQa4PFuqa5TngoVotTVvZfYwPqNoFU12ntiyK3V 0s3gA0BlBUPyS/8mAoz1aDzbuMSX0JgdenC4SsM6kRFLD2boX1pwySirNNtcDheBKzpC JypGgBHW71JA1m/XX/1ilF6G1RbKwmXypiiqA= Le 23 févr. 2011 à 18:43, Kevin Van Vechten a écrit : > You probably want to pass the -owners on option to hdiutil as described in the man page. > > By default, filesystem ownership on disk images is not honored. For example, you wouldn't want a .dmg downloaded from a website containing a setuid binary to work by default, would you? :-) > > Kevin Moreover, isn't the volume mounted nosuid by default? Axel _______________________________________________ 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 Kevin Van Vechten 23 Feb '11

23 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com You probably want to pass the -owners on option to hdiutil as described in the man page. By default, filesystem ownership on disk images is not honored. For example, you wouldn't want a .dmg downloaded from a website containing a setuid binary to work by default, would you? :-) Kevin On Feb 23, 2011, at 9:07 AM, Jay Buffington wrote: > Hi all, > > I am building a chroot management tool[1] for developers. It works > under linux and I'm in the process of adding Mac support. I've ran > into a couple of issues and could use a hand. > > I'm mounting a sparseimage and chroot'ing into it. When I do this ls > tells me that binaries such as sudo and ping correctly have the setuid > bit set and are owned by root. However, when I execute these > binaries, their call to geteuid returns the user id rather than 0 > (confirmed with dtruss[2]). The below commands, all executed on my > macbook pro running 10.5.7, demonstrate this: > > # build the image that i'll chroot into > export image_name=mac_os_x-10.5.7 > export image_file=~/images/$image_name.sparseimage > mkdir ~/images > hdiutil create -type SPARSE -fs HFS+ -volname $image_name -size 5g -attach \ > $image_file > for P in BaseSystem Essentials BSD X11User; do \ > sudo installer -target /Volumes/$image_name -pkg \ > '/Volumes/Mac OS X Install DVD/System/Installation/Packages/'$P.pkg;\ > done > > # mount some important directories for the chroot > sudo mount -t devfs devfs /Volumes/$image_name/dev > sudo mount -t fdesc -o union stdin /Volumes/mac_os_x-10.5.7/dev > sudo mkdir -p /Volumes/$image_name/Users/jaybuff > sudo bindfs /Users/jaybuff /Volumes/$image_name/Users/jaybuff > > $ # show that geteuid correctly returns 0 outside of the chroot: > $ cat euid.c > #include<stdio.h> > main() { printf("euid: %i\n", geteuid()); } > $ gcc euid.c -o euid > $ chmod 04755 euid > $ sudo chown root:wheel euid > $ ./euid > euid: 0 > > $ # copy it into the chroot > $ cp euid /Volumes/mac_os_x-10.5.7/tmp/euid > > $ sudo chroot /Volumes/mac_os_x-10.5.7 bash > > bash-3.2# ls -la /tmp/euid > -rwsr-xr-x 1 root wheel 12612 Feb 22 19:23 /tmp/euid > > bash-3.2# su - jaybuff > $ /tmp/euid > euid: 37964 > > $ id > uid=37964(jaybuff) gid=100(users) > groups=100(users),101(com.apple.sharepoint.group.1),98(_lpadmin),102(com.apple.sharepoint.group.2),80(admin),20(staff) > > Why does geteuid return 0 for a setuid binary outside of a chroot, but > not when executed inside a chroot? > > Thanks, > Jay > > [1] http://getjoot.org > [2] http://www.brendangregg.com/dtrace.html _______________________________________________ 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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chroot and setuid binaries
by Jay Buffington 23 Feb '11

23 Feb '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:date:message-id:subject:from:to :content-type; bh=fFJtjvJdP6Fx2h1pnI39r5tjsB8D/BxTCpkQgy9o2CQ=; b=WXpT1KNsshUzGIkmAhkPPB1oQUq4ektefKaRquk2ed8jkyJ1SlXT6zmnY8EbvZVXp/ cfckJ9qzFbH0yQAWqgs1r4fr6dCrqtVk76f53zClX6GuwwYa8/6xouUSy6y5IQ6775y2 G/pvEATnNSSDIP0CQC5UTXkr8jcY8XCIMO4rM= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=k1D8xLTUsFTPU/zIg7beN7Uu18YurwgLyJJgDLMIr8hfMllvBma6Ut9wLNehgADo/A Dqj1FopD4FpaQxBAKF0BixEHEyztwbOBfn1lbzRO9EJM19K5KUVItP2I/ZulxoqO8jjv XfEtK3nvJjpt6Xs2Q90lAiGOavuNGLOhUQTBA= Hi all, I am building a chroot management tool[1] for developers. It works under linux and I'm in the process of adding Mac support. I've ran into a couple of issues and could use a hand. I'm mounting a sparseimage and chroot'ing into it. When I do this ls tells me that binaries such as sudo and ping correctly have the setuid bit set and are owned by root. However, when I execute these binaries, their call to geteuid returns the user id rather than 0 (confirmed with dtruss[2]). The below commands, all executed on my macbook pro running 10.5.7, demonstrate this: # build the image that i'll chroot into export image_name=mac_os_x-10.5.7 export image_file=~/images/$image_name.sparseimage mkdir ~/images hdiutil create -type SPARSE -fs HFS+ -volname $image_name -size 5g -attach \ $image_file for P in BaseSystem Essentials BSD X11User; do \ sudo installer -target /Volumes/$image_name -pkg \ '/Volumes/Mac OS X Install DVD/System/Installation/Packages/'$P.pkg;\ done # mount some important directories for the chroot sudo mount -t devfs devfs /Volumes/$image_name/dev sudo mount -t fdesc -o union stdin /Volumes/mac_os_x-10.5.7/dev sudo mkdir -p /Volumes/$image_name/Users/jaybuff sudo bindfs /Users/jaybuff /Volumes/$image_name/Users/jaybuff $ # show that geteuid correctly returns 0 outside of the chroot: $ cat euid.c #include<stdio.h> main() { printf("euid: %i\n", geteuid()); } $ gcc euid.c -o euid $ chmod 04755 euid $ sudo chown root:wheel euid $ ./euid euid: 0 $ # copy it into the chroot $ cp euid /Volumes/mac_os_x-10.5.7/tmp/euid $ sudo chroot /Volumes/mac_os_x-10.5.7 bash bash-3.2# ls -la /tmp/euid -rwsr-xr-x 1 root wheel 12612 Feb 22 19:23 /tmp/euid bash-3.2# su - jaybuff $ /tmp/euid euid: 37964 $ id uid=37964(jaybuff) gid=100(users) groups=100(users),101(com.apple.sharepoint.group.1),98(_lpadmin),102(com.apple.sharepoint.group.2),80(admin),20(staff) Why does geteuid return 0 for a setuid binary outside of a chroot, but not when executed inside a chroot? Thanks, Jay [1] http://getjoot.org [2] http://www.brendangregg.com/dtrace.html _______________________________________________ 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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GCD with NSStream
by Joel Reymont 10 Feb '11

10 Feb '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:from:content-type:content-transfer-encoding :subject:date:message-id:to:mime-version:x-mailer; bh=PhJp/VnEvaoAr0/CabjzLP7NWZRrmvpgBz+M4RcUbMg=; b=h19Yj4PYPt+oqKgcvE3IWtxKo9KEZy8zhwtfsr1VxGT0jkK2WjSw//Nshp85Iq+uTM GltelAWQf/ObYM2Qd9muRF34i/zr/BFv7BJo3DvU/33mdi27zI5I+ZUPn0RSJn7N2Nav FHk9rSamPRfw0PjW27lMQPHi6DbOCblxNxS8w= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:content-type:content-transfer-encoding:subject:date:message-id :to:mime-version:x-mailer; b=ULcAvNpDsdy4gAcHd1HDYPmUIbpVk69FJzMhI8F6r/RBDGMtfo01XZ2CGitp2bdpD/ RCDJXHM9O52yxzAbwmNQcD/sec4BB3V+X8hqshEofb+vHT3wXTWog8Ou3nDQLpt9MMY8 l8frT1l9iOwE1EK9saeUPtEB85nYFPs4FzSdA= Is there a way I'm not aware of to integrate NSStream with GCD? Thanks, Joel -------------------------------------------------------------------------- - mac osx device driver ninja, kernel extensions and user-land usb drivers ---------------------+------------+--------------------------------------- http://wagerlabs.com | @wagerlabs | http://www.linkedin.com/in/joelreymont ---------------------+------------+--------------------------------------- _______________________________________________ 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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RTM resolve support
by Andrew White 10 Feb '11

10 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 Run as standard user, I get: "write failed: Operation not permitted" OK, so we'll run as root: "write failed: Operation not supported on socket" 2 questions: -- Andrew White _______________________________________________ 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… I have a routing socket. I can do RTM_GET operations fine. However, when I try to do an RTM_RESOLVE, things don't work. * If I want to do ARP resolution of addresses, is a routing socket the correct tool? Note that RTM_GET only works if the address is already in the ARP table. How do I ask the kernel to perform link layer address resolution if the address isn't currently known (ie force an arp)? * If RTM_RESOLVE is the correct tool, why is it giving "operation not supported"? This email sent to site_archiver(a)lists.apple.com

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Re: -mmacosx-version-min=10.6 behavior with additional libgcc_s.1.dylib's
by Jack Howarth 04 Feb '11

04 Feb '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Mutt/1.5.18 (2008-05-17) On Fri, Feb 04, 2011 at 10:55:36AM -0800, Nick Kledzik wrote: > Jack, > > Normally, when the linker produces a final linked image, it records which dylib each undefined symbol was found at build time. Then, at runtime, dyld only looks for those undefined symbols in the specific dylibs recorded. When a -flat_namespace is used, the linker records "flat lookup" for which dylib the undefinded was found in. At runtime, dyld will search each loaded image in load order looking for those undefined symbols when referenced from that -flat_namespace image. > > Given the above, there are two things that can go wrong: > 1) There is one over all chronological load order that is used when dyld searches for a symbol with flat lookup. The order of dependent libraries only matters if none of the dependent libraries have been already loaded. That is, you could have flat_namespace dylib A and dylib B. A links with dylib X and Y in that order while B links with Y and X in that order. At runtime, X and Y will be loaded in some order and that order defines how both A and B's undefined symbols are found. You can use DYLD_PRINT_LIBRARIES to see the actual load order of dylibs. You can use DYLD_PRINT_BINDINGS to see how all references are bound. > > 2) Mixing flat and two-level namespace dylibs can give unexpected results. Only the flat namespace dylibs can get their undefined symbols bound differently at runtime. All the other two-level namespace dylibs will continue to use what they recorded at build time. In the case of unwinding, that means two different unwinders could be in play and since they have different context pointers you can easily hand off an unwind context from one unwinder to another and boom. Nick, What confused me is how the unwinder symbols for FSF libgcc are ever accessed with the following linkage... -lgcc_ext.10.5 -lSystem -lgcc -no_compact_unwind -lSystem Since libgcc_ext.10.5.dylib is created as a stub only exporting those symbols from FSF libgcc_s.1.dylib which don't exist in libgcc_s.10.5.dylib, we believed that the unwinder symbols in FSF libgcc_s.1.dylib would be invisible to the linker even when -flat_namespace is used. Or are you saying that the -flat_namespace option allows dyld to look past the stub of libgcc_ext.10.5 directly at all symbols contained in the FSF libgcc_s.1.dylib? If so, what would be the best approach for linking here? I have suggested we adopt... -lSystem -lgcc_ext.10.5 -lgcc -no_compact_unwind -lSystem which flips linkage from... /sw/lib/gcc4.5/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1) to /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1) /sw/lib/gcc4.5/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0) This prevents the FSF libgcc unwinder being accidentally accessed under -flat_namespace. It also has the effect of having any overlapping symbols in libgcc_ext.10.5.dylib and libSystem (like ___divdc3) resolve from libSystem (hence the failures we then see in gcc.dg/torture/builtin-math-7.c's execution test due to <rdar://problem/7457013> ___divdc3 slightly wrong). > > What are you trying to accomplish? Does the libgcc_ext just have extra math stuff? Or are you trying to force the use of the gcc unwinder as well? If so, is this because of new gcc unwinder functionality? or just because you want to test the gcc unwinder? We are trying to make -flat_namespace more bullet-proof so that the FSF unwinder is never accessed by accident. FYI, xplor-nih is a mix of c, c++ and fortran which upstream builds on darwin entirely from the FSF gcc compilers. The xplor-nih program's code is stored in a series of shared libraries all built with -flat_namespace because they are used both from a standalone driver program (not currently linked with -flat_namespace) as well as from within python and tcl as bundles. In FSF gcc 4.5, we linked as... -lgcc_s.10.5 -lgcc_ext.10.5 -lgcc -no_compact_unwind -lSystem for both -macosx_version_min=10.5 and -macosx_version_min=10.6 so that even under -flat_namespace, the FSF libgcc unwinder was never accidentally used. My concern is that FSF gcc 4.6 currently only links that way for -macosx_version_min=10.5 and use... -lgcc_ext.10.5 -lgcc -no_compact_unwind -lSystem instead for -macosx_version_min=10.6. This worries me on a couple of issues... 1) Since we are not linking -lSystem before -lgcc, don't we risk pulling in symbols like ___enable_execute_stack from /sw/lib/gcc4.6/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/libgcc.a under the FSF gcc 4.6 compiler? I would think that the absence of either the initial -lgcc_s.10.5 or -lSystem linkage would expose the symbols from the -lgcc linkage? 2) Since -flat_namespace has been long recommended for porting unix software under Mac OS X, the fact that the current linkage in FSF gcc 4.6 can accidentally invoke the FSF libgcc unwinder if both the shared libs and executable aren't all compiled with -flat_namespace is a concern. My experience has been that -flat_namespace (when used) has only been applied to the shared library builds and not the executables. Jack > > -Nick > > On Feb 4, 2011, at 7:28 AM, Jack Howarth wrote: > > Nick, > > Appended is a very simple test case that I found for PR47558 that demonstrates > > the problem and the proposed fix. > > Jack > > > > The following works as a testcase for PR47558 > > > > test_main.c > > -------------------------- > > void main (void) > > { > > extern int unwindcall(void); > > int i; > > i=unwindcall(); > > } > > -------------------------- > > > > test_call.c > > --------------------------- > > int unwindcall (void) > > { > > static __thread i; > > i+i; > > _Unwind_Resume ((void *)0); > > return i; > > } > > ---------------------------- > > > > ./dist/bin/gcc -dynamiclib -o libtestcall.dylib -flat_namespace -undefined > > suppress -single_module test_call.c > > ./dist/bin/gcc -o PR47558.exe test_main.c ./libtestcall.dylib > > > > otool -L PR47558.exe > > PR47558.exe: > > libtestcall.dylib (compatibility version 0.0.0, current version 0.0.0) > > /Users/howarth/dist/lib/libgcc_s.1.dylib (compatibility version 1.0.0, > > current version 1.0.0) > > /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version > > 125.2.1) > > > > ./PR47558.exe > > Abort > > > > gdb ./PR47558.exe > > GNU gdb 6.3.50-20050815 (Apple version gdb-1510) (Wed Sep 22 02:45:02 UTC 2010) > > Copyright 2004 Free Software Foundation, Inc. > > GDB is free software, covered by the GNU General Public License, and you are > > welcome to change it and/or distribute copies of it under certain conditions. > > Type "show copying" to see the conditions. > > There is absolutely no warranty for GDB. Type "show warranty" for details. > > This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared > > libraries .... done > > > > (gdb) r > > Starting program: /Users/howarth/PR47558.exe > > Reading symbols for shared libraries +++. done > > > > Program received signal SIGABRT, Aborted. > > 0x00007fff87c05616 in __kill () > > (gdb) bt > > #0 0x00007fff87c05616 in __kill () > > #1 0x00007fff87ca5cca in abort () > > #2 0x00000001000147a6 in uw_init_context_1 (context=0x7fff5fbfe5d0, > > outer_cfa=0x7fff5fbfe800, outer_ra=0x100003f75) at > > ../../../gcc/libgcc/../gcc/unwind-dw2.c:1265 > > (gdb) > > > > For the testcase in Comment 56 using my proposed patch from Comment 45... > > > > gcc-4 -dynamiclib -o libtestcall.dylib -flat_namespace -undefined suppress > > -single_module test_call.c > > gcc-4 -o PR47558.exe test_main.c ./libtestcall.dylib > > > > otool -L ./PR47558.exe > > ./PR47558.exe: > > libtestcall.dylib (compatibility version 0.0.0, current version 0.0.0) > > /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version > > 125.2.10) > > /sw/lib/gcc4.6/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current > > version 1.0.0) > > > > gdb ./PR47558.exe > > Program received signal EXC_BAD_ACCESS, Could not access memory. > > Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000010 > > 0x00007fff839d3c35 in _Unwind_Resume () > > (gdb) bt > > #0 0x00007fff839d3c35 in _Unwind_Resume () > > #1 0x0000000100003f75 in unwindcall () > > #2 0x0000000100000f7b in main () > > _______________________________________________ Do not post admin requests to the list. 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