July 2012 - Darwin-kernel - lists.apple.com

Working with VFS (reading/writing files)
by Mehdi Esmaeelpour 21 Jul '12

21 Jul '12

Hi I want to reading and writing files from I/O kit layer.in darwin-dev list i ask this question and answer was VFS! how i use vas?any docs or sample codes? Thanks _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: kqueue timer interval fence post error?
by Paul Albrecht 19 Jul '12

19 Jul '12

On Wed, 2012-07-18 at 12:40 -0500, Shantonu Sen wrote: > <http://www.opensource.apple.com/source/xnu/xnu-1699.26.8/> > > Timers can skew for a variety of reasons, including system load, and power management. Considering that 20ms isn't that much more than a scheduling quantum, actual delivery of notifications can vary widely, especially on UP systems. > Hi Shantonu, Forgot to cc the list when I replied so again... I don't think any of the reasons you cited account for kqueue periodic timer lag because I can get acceptable 20 msec timing using either linux or freebsd w/fix timers. Here's a link to the thread I mentioned in the previous post on the free-bsd hackers list: http://lists.freebsd.org/pipermail/freebsd-hackers/2012-July/039907.html I'm not sure it's relevant because the bsd subsystem looks to me like it's been changed to use the callout framework which is still a work in progress on freebsd. Does the callout framework used in the bsd subsystem preclude accurate timing or is there some other issue? > Shantonu > > On Jul 18, 2012, at 7:21 AM, Paul Albrecht <albrecht(a)glccom.com> wrote: > > > Hi, > > > > Doesn't seem like the kqueue timer works correctly on os x. When I use > > the timer on my mac it consistently runs slow. Here's some test code: > > > > #include <stdio.h> > > #include <stdlib.h> > > #include <string.h> > > #include <unistd.h> > > #include <errno.h> > > #include <sys/types.h> > > #include <sys/event.h> > > #include <sys/time.h> > > > > int > > main(void) > > { > > int i,msec; > > int kq,nev; > > struct kevent inqueue; > > struct kevent outqueue; > > struct timeval start,end; > > > > if ((kq = kqueue()) == -1) { > > fprintf(stderr, "kqueue error!? errno = %s", strerror(errno)); > > exit(EXIT_FAILURE); > > } > > EV_SET(&inqueue, 1, EVFILT_TIMER, EV_ADD | EV_ENABLE, 0, 20, 0); > > > > gettimeofday(&start, 0); > > for (i = 0; i < 50; i++) { > > if ((nev = kevent(kq, &inqueue, 1, &outqueue, 1, NULL)) == -1) { > > fprintf(stderr, "kevent error!? errno = %s", strerror(errno)); > > exit(EXIT_FAILURE); > > } else if (outqueue.flags & EV_ERROR) { > > fprintf(stderr, "EV_ERROR: %s\n", strerror(outqueue.data)); > > exit(EXIT_FAILURE); > > } > > } > > gettimeofday(&end, 0); > > > > msec = ((end.tv_sec - start.tv_sec) * 1000) + (((1000000 + end.tv_usec - start.tv_usec) / 1000) - 1000); > > > > printf("msec = %d\n", msec); > > > > close(kq); > > return EXIT_SUCCESS; > > } > > > > I originally noticed the problem on freebsd. After I posted to the > > freebsd-hackers mailing list I got a fix, but that doesn't do much good > > on my mac since I don't have the source. > > > > -- > > Paul Albrecht > > > > _______________________________________________ > > Do not post admin requests to the list. They will be ignored. > > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > > Help/Unsubscribe/Update your Subscription: > > https://lists.apple.com/mailman/options/darwin-kernel/ssen%40apple.com > > > > This email sent to ssen(a)apple.com > -- Paul Albrecht _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: Active Directory bind, opendirectoryd, and indentitysvc()
by comex 18 Jul '12

18 Jul '12

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Active Directory bind, opendirectoryd, and indentitysvc()
by Jon Shier 18 Jul '12

18 Jul '12

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Re: kqueue timer interval fence post error?
by Shantonu Sen 18 Jul '12

18 Jul '12

<http://www.opensource.apple.com/source/xnu/xnu-1699.26.8/> Timers can skew for a variety of reasons, including system load, and power management. Considering that 20ms isn't that much more than a scheduling quantum, actual delivery of notifications can vary widely, especially on UP systems. Shantonu On Jul 18, 2012, at 7:21 AM, Paul Albrecht <albrecht(a)glccom.com> wrote: > Hi, > > Doesn't seem like the kqueue timer works correctly on os x. When I use > the timer on my mac it consistently runs slow. Here's some test code: > > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > #include <unistd.h> > #include <errno.h> > #include <sys/types.h> > #include <sys/event.h> > #include <sys/time.h> > > int > main(void) > { > int i,msec; > int kq,nev; > struct kevent inqueue; > struct kevent outqueue; > struct timeval start,end; > > if ((kq = kqueue()) == -1) { > fprintf(stderr, "kqueue error!? errno = %s", strerror(errno)); > exit(EXIT_FAILURE); > } > EV_SET(&inqueue, 1, EVFILT_TIMER, EV_ADD | EV_ENABLE, 0, 20, 0); > > gettimeofday(&start, 0); > for (i = 0; i < 50; i++) { > if ((nev = kevent(kq, &inqueue, 1, &outqueue, 1, NULL)) == -1) { > fprintf(stderr, "kevent error!? errno = %s", strerror(errno)); > exit(EXIT_FAILURE); > } else if (outqueue.flags & EV_ERROR) { > fprintf(stderr, "EV_ERROR: %s\n", strerror(outqueue.data)); > exit(EXIT_FAILURE); > } > } > gettimeofday(&end, 0); > > msec = ((end.tv_sec - start.tv_sec) * 1000) + (((1000000 + end.tv_usec - start.tv_usec) / 1000) - 1000); > > printf("msec = %d\n", msec); > > close(kq); > return EXIT_SUCCESS; > } > > I originally noticed the problem on freebsd. After I posted to the > freebsd-hackers mailing list I got a fix, but that doesn't do much good > on my mac since I don't have the source. > > -- > Paul Albrecht > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/darwin-kernel/ssen%40apple.com > > This email sent to ssen(a)apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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kqueue timer interval fence post error?
by Paul Albrecht 18 Jul '12

18 Jul '12

Hi, Doesn't seem like the kqueue timer works correctly on os x. When I use the timer on my mac it consistently runs slow. Here's some test code: #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <errno.h> #include <sys/types.h> #include <sys/event.h> #include <sys/time.h> int main(void) { int i,msec; int kq,nev; struct kevent inqueue; struct kevent outqueue; struct timeval start,end; if ((kq = kqueue()) == -1) { fprintf(stderr, "kqueue error!? errno = %s", strerror(errno)); exit(EXIT_FAILURE); } EV_SET(&inqueue, 1, EVFILT_TIMER, EV_ADD | EV_ENABLE, 0, 20, 0); gettimeofday(&start, 0); for (i = 0; i < 50; i++) { if ((nev = kevent(kq, &inqueue, 1, &outqueue, 1, NULL)) == -1) { fprintf(stderr, "kevent error!? errno = %s", strerror(errno)); exit(EXIT_FAILURE); } else if (outqueue.flags & EV_ERROR) { fprintf(stderr, "EV_ERROR: %s\n", strerror(outqueue.data)); exit(EXIT_FAILURE); } } gettimeofday(&end, 0); msec = ((end.tv_sec - start.tv_sec) * 1000) + (((1000000 + end.tv_usec - start.tv_usec) / 1000) - 1000); printf("msec = %d\n", msec); close(kq); return EXIT_SUCCESS; } I originally noticed the problem on freebsd. After I posted to the freebsd-hackers mailing list I got a fix, but that doesn't do much good on my mac since I don't have the source. -- Paul Albrecht _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: About partition scheme.
by Phil Jordan 09 Jul '12

09 Jul '12

On Mon, Jul 9, 2012 at 5:08 PM, Flost Li <havefan2012(a)gmail.com> wrote: > Indeed, we could not protecting some body to format the system disk whos > have the root privileges, > But, there is less people has the privileges to do "kextunload" than has > the privileges to executing "dd if=/dev/zero of=/dev/disk2s2". isnt it? That depends entirely on the permissions for /dev/disk2s2. phil _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: About partition scheme.
by Flost Li 09 Jul '12

09 Jul '12

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Re: About partition scheme.
by Phil Jordan 09 Jul '12

09 Jul '12

On Mon, Jul 9, 2012 at 5:05 AM, Flost Li <havefan2012(a)gmail.com> wrote: > [Flost]: consider that if i would like to use disk2s2 to do some encrypt > read/write. In your example, if the client operate with disk3, than you > could encrypt/decrypt the data read/written, but if some read/write through > disk2s2, it could only get the raw data, > Isn't it? > What I'd like to do is that I should make sure that people could not > read/write through disk2s2, than no one could read the raw data. Anyone with root privileges can just unload your kext, removing any "protection" it offers, or load another kext that grabs disk2s2 inside the kernel. There's no way to stop this. Anyway, if your crypto is any good, access to the ciphertext isn't a problem. If it is a problem, why bother with crypto? Anyway, FileVault2/CoreStorage already implements all of this. How it works is explained in a WWDC2012 talk: Session 709, "What's new in the filesystem." I suggest you look at that. phil _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: About partition scheme.
by Flost Li 09 Jul '12

09 Jul '12

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