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

Re: symlinks, lstat, relative/absolute combos
by Tilghman Lesher 22 Mar '11

22 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=nooebOFFeZJ8U7v45op4RVa2xSIor8pJssPLNUgGsYo=; b=bXIvnhI9otUXAk/4stiksdnEDqa630jJKB91xU566t+dAsTbgP6N/XCTBtAo3U06ND Oto1044JuluT+QzWrh1Yip0pMEmn+T4qLwTpb1a7wHN/zBbS+1QMRTMaLcKPMY5tvPsm 8bmCzOIdJa8gNI3bekNxy5A9LCuZVg0r8JfHw= 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=E38mqtqpK36m+8t3c1FKSedO4cLhyfCE8FZ9rTwTYQ/RrIhwGTUWcgDO98uuxNw/dt s7MBxTypHD1pLRPAgMWupc9UUer0JwjkKXK6tSA0wESVnOk+U1gREh27ghlyqsQPnzfq m1oBMMGPbvJBSrfG3xC4i67Ds+44eAaZUJigE= Reply-by: Wed, 19 Jan 2011 16:20:00 -0600 User-agent: KMail/1.13.5 (Linux/2.6.32-30-server; KDE/4.4.5; x86_64; ; ) On Tuesday 22 March 2011 14:56:20 James Peach wrote: > On 22 March 2011 11:18, Tilghman Lesher <tilghman(a)meg.abyt.es> wrote: > > On Tuesday 22 March 2011 13:03:15 James Peach wrote: > >> On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: > >> > Hi , > >> > I was working on Mac symlinks(unix style) and encountered things > >> > I couldn't find information on through web searches. I was > >> > thinking these are Mac specific flags and meanings, so with that > >> > intro: when you lstat() a symlink, lstat states that st_size will > >> > be the size of the pathname for the link, what does it mean when > >> > it is a link with st_size = 0, yet it does have a link? > >> > >> I believe that the st_size of a symlink is a filesystem > >> implementation detail. You should not rely on it for anything > >> serious. > > > > That may be, but it's still in POSIX: > > http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html > > Not every filesystem is posix compliant. If it's a native filesystem of Mac OS X, which the devfs filesystem certainly is, then for Apple to claim that Mac OS X conforms to POSIX 1003.1 (which it does), the kernel developers need to fix the bug. I realize I may be stepping on some toes, but denying that it's a bug is a ridiculous stance. -- 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: symlinks, lstat, relative/absolute combos
by James Peach 22 Mar '11

22 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 :content-transfer-encoding; bh=uBb6jouebnyWllFhVAvZOLkizjq1xcqI8R4/ieLFWdU=; b=a0zGpY2mkFz5SXGfIxRuabPoRV3yBpkgXVyQeWdBuVKczAGhO8BE0BOkmPxA6m8PpF 9gS1hrjQmb+4FJTja4j3TePxei6D7jIGu4pJTyr0w2kDvQuuiRUrrhLcu8fns1FMj5Bf +goJ0+5WoDNPMiROegcdn78rkDmNps4iuKTX4= 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=h8lvKLxvE61CZ1MhxwULBmlLBh9sFXAlOj3Eit9aceiznlfjZzaY2Gmm/+12SXzZT5 c5JeEgvDxJQoEox4aI6y67dcX48AqaWO/ndiAOrZFcccq0Q+y2AHE5hY/sld0wzU99lp 7E5HFrATJvYmInvV8YwM4W1a1/o6bbs1Z+cfY= On 22 March 2011 11:18, Tilghman Lesher <tilghman(a)meg.abyt.es> wrote: > On Tuesday 22 March 2011 13:03:15 James Peach wrote: >> On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: >> > Hi , >> > I was working on Mac symlinks(unix style) and encountered things I >> > couldn't find information on through web searches. I was thinking >> > these are Mac specific flags and meanings, so with that intro: when >> > you lstat() a symlink, lstat states that st_size will be the size of >> > the pathname for the link, what does it mean when it is a link with >> > st_size = 0, yet it does have a link? >> >> I believe that the st_size of a symlink is a filesystem implementation >> detail. You should not rely on it for anything serious. > > That may be, but it's still in POSIX: > http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html Not every filesystem is posix compliant. > > I just verified on my own system that it is working correctly for an > HFS+ filesystem. The OP may wish to verify his own code is working > correctly by comparing his output to that of 'stat -x {file}'. > > -- > 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/jorgar%40gmail.com > > This email sent to jorgar(a)gmail.com > -- James Peach | jorgar(a)gmail.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… This email sent to site_archiver(a)lists.apple.com

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Re: symlinks, lstat, relative/absolute combos
by Tilghman Lesher 22 Mar '11

22 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=QCdtScolfBPTnSfWkyIGzgFWVnDRfmwaGmwa9fA3/HY=; b=KjJeEzo/b2cDcZSTWjJQMtTOnlMuqhMHV6u9FNKwDx2Ch4AiC7X1+qJsj67xEPR7+f tMgLnMOWQ2AwHOB9w9mn6dFvLV+Niuj2PcY6nc/4B42zH/oQM/KL29VKKqyWVMbI6+bY //PjcHI0xLZYUrCXWqjMD6GVbyAXZd7AoxrL4= 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=HCsVVnjbWBNJDAkxI92A8QwN3iwTu0kzQpoS7iOrPQvUom8eJA6bixZhd9R7rnsxha KceLAGgmNrD7E7rNCemWAgVhlsebdjaJMvlt4tNgOqJchUR0GWML3Wqyhhx95eBFDeG1 +7Cm1RIWrKNpE5O3Katf3N7Sh7tUD/e7aknJw= Reply-by: Wed, 19 Jan 2011 16:20:00 -0600 User-agent: KMail/1.13.5 (Linux/2.6.32-30-server; KDE/4.4.5; x86_64; ; ) On Tuesday 22 March 2011 13:25:40 Steven Abner wrote: > On Mar 22, 2011, at 2:18 PM, Tilghman Lesher wrote: > > On Tuesday 22 March 2011 13:03:15 James Peach wrote: > >> On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: > >>> Hi , > >>> > >>> I was working on Mac symlinks(unix style) and encountered things I > >>> > >>> couldn't find information on through web searches. I was thinking > >>> these are Mac specific flags and meanings, so with that intro: when > >>> you lstat() a symlink, lstat states that st_size will be the size of > >>> the pathname for the link, what does it mean when it is a link with > >>> st_size = 0, yet it does have a link? > >> > >> I believe that the st_size of a symlink is a filesystem > >> implementation detail. You should not rely on it for anything > >> serious. > > > > That may be, but it's still in POSIX: > > http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html > > > > I just verified on my own system that it is working correctly for an > > HFS+ filesystem. The OP may wish to verify his own code is working > > correctly by comparing his output to that of 'stat -x {file}' > > I had only found one instance so far where the Mac returned st_size = 0. > I didn't wish to assume anything! The case was in testing "/dev/stdin" > which has relative link to "fd/0". Yep, probably need to report that to the Darwin team as a bug. Just verified that it reports correctly on both FreeBSD and Linux. If you don't, I will, but the report needs to be clear that the determining specification is POSIX, and this is needed for POSIX compliance. -- 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: symlinks, lstat, relative/absolute combos
by Steven Abner 22 Mar '11

22 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Mar 22, 2011, at 2:18 PM, Tilghman Lesher wrote: > On Tuesday 22 March 2011 13:03:15 James Peach wrote: >> On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: >>> Hi , >>> I was working on Mac symlinks(unix style) and encountered things I >>> couldn't find information on through web searches. I was thinking >>> these are Mac specific flags and meanings, so with that intro: when >>> you lstat() a symlink, lstat states that st_size will be the size of >>> the pathname for the link, what does it mean when it is a link with >>> st_size = 0, yet it does have a link? >> >> I believe that the st_size of a symlink is a filesystem implementation >> detail. You should not rely on it for anything serious. > > That may be, but it's still in POSIX: > http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html > > I just verified on my own system that it is working correctly for an > HFS+ filesystem. The OP may wish to verify his own code is working > correctly by comparing his output to that of 'stat -x {file}' I had only found one instance so far where the Mac returned st_size = 0. I didn't wish to assume anything! The case was in testing "/dev/stdin" which has relative link to "fd/0". _______________________________________________ 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: symlinks, lstat, relative/absolute combos
by Tilghman Lesher 22 Mar '11

22 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=pXg6vU9eH29sixGcAxUP0jCmnWmjFroIxHZy3mHByRw=; b=W7BfISTc+Wb/+eAHC1iQ8I6C0BRiNtEW8KuEo+lK0Hv3itA3fCc/K0gdQwxMaTqF/4 Dok3lKjTmzlrFPbpOEGE9cxNvn3wCwtiU9XkSY9kKxKnPU8Qd3v2XTDx/k8myRE5XWU4 YIA/9lU4QSK4fTTQqWQCWpevCcwLpFVjqrJ0U= 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=be3+y9J9fafyTNoNpkPF/ZwTYv4UztzeFGNIgj2qENectrOm8cOfPeelAyruY7dCGK h0Qi82tK/qaOIXH3ruO/dE3y2Rh6qqrYogY2A45E8BZLVZWkFYh2EcnSN+9aTNBpXGAa 3z76gwcN8e0UX39oYefKICmVafs1kGQDNMnGo= Reply-by: Wed, 19 Jan 2011 16:20:00 -0600 User-agent: KMail/1.13.5 (Linux/2.6.32-30-server; KDE/4.4.5; x86_64; ; ) On Tuesday 22 March 2011 13:03:15 James Peach wrote: > On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: > > Hi , > > I was working on Mac symlinks(unix style) and encountered things I > > couldn't find information on through web searches. I was thinking > > these are Mac specific flags and meanings, so with that intro: when > > you lstat() a symlink, lstat states that st_size will be the size of > > the pathname for the link, what does it mean when it is a link with > > st_size = 0, yet it does have a link? > > I believe that the st_size of a symlink is a filesystem implementation > detail. You should not rely on it for anything serious. That may be, but it's still in POSIX: http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html I just verified on my own system that it is working correctly for an HFS+ filesystem. The OP may wish to verify his own code is working correctly by comparing his output to that of 'stat -x {file}'. -- 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: symlinks, lstat, relative/absolute combos
by James Peach 22 Mar '11

22 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 :content-transfer-encoding; bh=MDprEJungtZTVATEwuIncWjEp3qNOx2NoO/WNEI5hw8=; b=cIZqawW3fC/OTTd1UQthPlKzgur9G7lG8JWJm/rA32yXHG+mpwA2Q0ofkGI9Y/PZbY pTMKRx/8Lh9T+aQM92Yp3TBtTd0PaFmy4EdaLjk75941TjkAR9ab/obkjDWUzA94MbHW 22d+rvcr/QFrXclMS5DObIIdOIiLJWBPAIYKU= 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=QThMbuunvachZD/1QWeqodY8REA5i+qcrSBM+zPoO5PoQDyHd5qrucEQFaKrxlccR3 vdmpWvIukrxiOZGrOowSJ25IC4mHUaajCbSbOQdjx+MhlWQqEi+fQN0Xadk+2X9zhyMO O7yVxTEoyo2pKPK8pyz0z+b32YYD0uogH9RQo= On 22 March 2011 06:08, Steven Abner <pheonix(a)zoomtown.com> wrote: > Hi , > I was working on Mac symlinks(unix style) and encountered things I couldn't find information on through web searches. > I was thinking these are Mac specific flags and meanings, so with that intro: when you lstat() a symlink, lstat states that > st_size will be the size of the pathname for the link, what does it mean when it is a link with st_size = 0, yet it does have a link? I believe that the st_size of a symlink is a filesystem implementation detail. You should not rely on it for anything serious. > And what is the special meaning of a return when it mixes relative paths with absolute paths? Example: a return of ../..//System . >Should "../../" be ignored and jump to System directory of of root? Or is "/" before "System" suppose to mean ignore me please? >Currently my code just returns "//" is an error. No. Any number of '/' characters is legal and is the same as a single '/'. Any number of '/./' path components is also legal and is also the same so a single '/'. > As I read it: from here (relative path) go to parent (..), from here (/) go to parent (..) > from here (/) go to (/System). Or is "//" an abbreviated "/./" , which currently seems unsupported? So to process the path "../..//System", take the current working directory, go back one path component for each ".." component, then append one component named "System". Wherever you end up after that is the right place. Note that the path "/../../.." resolves to just "/". That is, the parent directory of "/" is "/". You can trivially demonstrate this my doing "cd /../../../../." -- James Peach | jorgar(a)gmail.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… This email sent to site_archiver(a)lists.apple.com

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Re: symlinks, lstat, relative/absolute combos
by Jonas Maebe 22 Mar '11

22 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On 22 Mar 2011, at 14:08, Steven Abner wrote: Jonas _______________________________________________ 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… a return of ../..//System . Should "../../" be ignored and jump to System directory of of root? Or is "/" before "System" suppose to mean ignore me please? Currently my code just returns "//" is an error. As I read it: from here (relative path) go to parent (..), from here (/) go to parent (..) from here (/) go to (/System). Or is "//" an abbreviated "/./" , which currently seems unsupported? // means the same as / in practice (it sometimes happens because of e.g. scripts that concatenate a path already ending in / with "/ $subdir" or so). So in your case, it simply means ../../System This email sent to site_archiver(a)lists.apple.com

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symlinks, lstat, relative/absolute combos
by Steven Abner 22 Mar '11

22 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hi , I was working on Mac symlinks(unix style) and encountered things I couldn't find information on through web searches. I was thinking these are Mac specific flags and meanings, so with that intro: when you lstat() a symlink, lstat states that st_size will be the size of the pathname for the link, what does it mean when it is a link with st_size = 0, yet it does have a link? And what is the special meaning of a return when it mixes relative paths with absolute paths? Example: a return of ../..//System . Should "../../" be ignored and jump to System directory of of root? Or is "/" before "System" suppose to mean ignore me please? Currently my code just returns "//" is an error. As I read it: from here (relative path) go to parent (..), from here (/) go to parent (..) from here (/) go to (/System). Or is "//" an abbreviated "/./" , which currently seems unsupported? Thanks for listening, and sorry if these may seem like dumb questions but the st_size one really makes coding hard, at least my current approach in my code. Steve _______________________________________________ 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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Open Source Releases
by William Siegrist 18 Mar '11

18 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com The Darwin Team has released the source code for DevTools 3.2.5, 3.2.6, and 4.0, as well as iOS 4.1, 4.2, and 4.3 (with the exception of WebCore and JavaScriptCore for 4.3). We'll finish the posting for iOS 4.3 soon. http://opensource.apple.com/ Thank you, William Siegrist _______________________________________________ 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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CFFileDescriptor changes between 10.6.4 and 10.6.6
by A.M. 17 Mar '11

17 Mar '11

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hello, I had previously successfully used CFFileDescriptor to receive notifications on writes to an in-process pipe in 10.6.0-10.6.4. After upgrading to 10.6.6, I receive one notification and then no more (and yes, I re-enable the callback for read events). I believe CFFileDescriptor previously used pthread and a separate kqueue for each monitored file descriptor but now libdispatch is used and I would like to better understand how this change affected my application. In my case, the pipe's readable fd is added to my own kqueue and to the main NSRunLoop via the CFFileDescriptor (so that events implied by pipe activity can be serviced on whichever thread is available). On 10.6.6, the CFFileDescriptor gets called once and then never again- the same code worked reliably under 10.6.4 and older versions. The symptoms seem to be a reaction to the same fd in multiple kqueues- at least that's my best guess. My solution was to use libdispatch and trash CFFileDescriptor on 10.6. This indicates that the bug must be in the file descriptor handling within CFFileDescriptor itself. (I did confirm that the fd is not close()'d.) I am curious if anyone has seen similar problems with CFFileDescriptor. Cheers, M _______________________________________________ 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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