April 2008 - Darwin-kernel - lists.apple.com

Re: kernel thread join?
by Godfrey van der Linden 14 Apr '08

14 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Cheers Godfrey On 2008-04-12, at 5:08 , Duane Murphy wrote: What is the equivalent of pthread_join() for a kernel thread? 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… There isn't really a 100% reliable way of waiting for a thread to terminate completely. However that isn't really a problem. The key is to recognise what you are really trying to do. Presumably you are trying to clean up resources that the thread may be using? In this case the correct kernel way of cleaning this up is just to reference count your resources. Then it doesn't matter exactly what order the objects get released in. There are a couple of other tricks but the OSObject reference counting will probably get you out of trouble. I am using IOThreadCreate() to create a new thread. At some later point I indicate to that thread to stop. How do I detect that the thread as exited? ...Duane This email sent to site_archiver(a)lists.apple.com

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Re: Baudrate of Ethernet interface
by mm w 12 Apr '08

12 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=ofn9eso6bF3Q7UGYp6q1j5WW0qYN+y3dgt150im63Z4=; b=WCJpjelTbeixFXkS6law6ha/HXYGttNlz3tSYTbPAth+PB1psiBJNSq30idjuVFYYTnbnyoRdoZYkV9wSdLZfMd6+wjb0fgUByvvfbK/4dVGH+bWTr72B5KBoS5EXsMkdDVlSahdSZOIGhQl/Bw5++zc6xVJMhvY6BezxzRH4GI= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=F70/I7whX8y+eNzevYv2+1qwJSInbzjnyGS4EQcWWbAqGcq5TdIyeqRCyHh04OjecUn4cbB/0Rkw7TyrMYDqDKnRGSRS/sirJB2VhIFr1yheAq9dk8RjQldXrgoj7c9QRaMpR1ox3YJHmAfZk2lQ8vwtgnS10X0JYXGrc2v7hpc= Hi this is the common default value: if(ifnet.if_type == IFT_ETHER) return (unsigned long) 10000000; -> ifnet_t->if_data.ifi_baudrate; I think you have to send you a message /* * Message format for use in obtaining information about interfaces * from sysctl and the routing socket */ struct if_msghdr { On Sat, Apr 12, 2008 at 5:08 AM, Rakesh Singhal <rakesh.singhal(a)gmail.com> wrote: > HI all > > During development of a NKE, I need some information like MTU and link speed > of an Ethernet interface on system. I am using two functions > ifnet_mtu(ifnet_t interface) and ifnet_baudrate(ifnet_t interface) to get > MTU and baudrate. I think the link speed is baudrate in bits per second. > Here I am getting proper MTU but baudrate always I am getting is 10000000. I > check the link speed in property from IORegistry and it is different from > what I am getting. Can someone explain me, how can I measure the link speed > on any Ethernet interface. > > Thanks and regards > Rakesh > > _______________________________________________ > 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: > > http://lists.apple.com/mailman/options/darwin-kernel/openspecies%40gmail.com > > This email sent to openspecies(a)gmail.com > -- -mmw _______________________________________________ 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Baudrate of Ethernet interface
by Rakesh Singhal 12 Apr '08

12 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:mime-version:content-type; bh=rzjGwE72MKlksjeeGz8NqnfbrQnAvwkPsXPeYY6y06M=; b=SlCU+IiJKGfXS4X08gC/dK+BQxUmXsjVT0T//oeCjXYju860ZVyZCnw0IQ3BDKV0gPv3R4dR16169f8fU3WQOaGg4IE3gCfbXbpKcZ775zygBdmmeP+mXrTTu9zdVuxre1vRSsBb7TnGP7QZC3PqwUkBmdYAa6G0u+m0aWUiRFw= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type; b=MpUfD/BsOhIDUaJGRm7OVUUjabsZC15BPrPcSerI6tIGK30lbZGKG7c2nC7Iyb8MPf8joX57zYuvy9kQKnUKBA1R61qDA/IMvsv8OQCjlZiVCANSBUIjgQSsa5c5g4BEYdKH3qvTzmjxobbuyXFTk2Ki/6ro+DoAHcbh11WqtHM= _______________________________________________ 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: http://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: Version of a dynamic library
by Michael Smith 12 Apr '08

12 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.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: http://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: kernel thread join?
by Michael Smith 12 Apr '08

12 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Apr 11, 2008, at 12:08 PM, Duane Murphy wrote: What is the equivalent of pthread_join() for a kernel thread? = Mike _______________________________________________ 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I am using IOThreadCreate() to create a new thread. At some later point I indicate to that thread to stop. How do I detect that the thread as exited? You don't. The kernel doesn't exit, so typically your thread signals a condition to acknowledge the request and then terminates. If you know the thread's safely asleep without state, and you have arranged accordingly beforehand, you can just terminate it out of hand. This email sent to site_archiver(a)lists.apple.com

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Re: kernel panic on readBytes
by Michael Smith 12 Apr '08

12 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Apr 10, 2008, at 8:00 AM, Timur Alperovich wrote: Hey Timur, Where does the physical address in inStruct->offset come from? getPhysicalSegment()? The address is passed in from userspace. I wrote a little daemon that simply goes from 0x0 to the highest possible address (I figure that out by getting the maximum amount of ram on the machine through a sysctl call) and pass it to the kernel extension. The kernel then returns a 32-bit hash value for each page. I thought that should work ok, but is it a problem? Yes, that's definitely a problem. = Mike _______________________________________________ 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… There's no guarantee that physical memory is addressed starting at zero, or that the kernel owns all of it. You aren't allowed to do that; unless the kernel gives you physical memory, leave it alone. This email sent to site_archiver(a)lists.apple.com

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Re: Version of a dynamic library
by Terry Lambert 11 Apr '08

11 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi All, Can anyone help me in this regard, Is there some other way to accomplish the same task, But if you are still committed to doing this anyway, here's how: -- Terry _______________________________________________ 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… On Apr 10, 2008, at 3:35 AM, anukriti_shrimal wrote: I am currently working on Mac Os x 10.4.7 I am trying to retrieve the version of a dynamic library (.dylib) from its full path. While investigating source code of dyld, I found that the mach_header or mach_header_64 contains the version information. So, I tried to get the mach_header from the file contents. But I was unable to do so. I don't think this is going to end up being useful to you, since once something is linked, it's already linked, and library versions are typically distinguished by path. Also, you will not necessarily be able to select the same slice from the Mach-O binary that the kernel or dyld would select, since the kernel selects based on grading the binary, and there are hooks so that user processes can interfere with the natural choice. This causes the dydld corresponding to the cpu_type/cpu_subtype of the original binary, from the file referenced by the LC_LOAD_DYLINKER section of that binary, to be loaded. Then dyld, when going to load libraries, does so based on its own idea of grading in version number matching based on the original binary file contents. Taken together, this makes it real hard to guess what slice of a fat file was loaded from a library by dyld. Since on top of that, you can lipo different versions of libraries for different architectures in a given fat file, the answer for the version and compatibility version won't necessary match between multiple Mach-O files in a single binary, if you hit a degenerate case. (1) Open the file (2) Read the first page into a buffer (3) Cast the buffer to a struct fat_header * (4) Look at the magic numner: (a) FAT_MAGIC - this is a FAT file from this architecture (b) FAT_CIGAM - this is a FAT file from a PPC/Intel for an Intel/PPC (i) byte swap all fat_header elements (c) Neither - GOTO #8 AND HOPE FOR NON-FAT MACH-O FILE (5) Select the appropriate Mach-o binary from the fat_header element list (6) Seek to its offset in the file (7) Re-read the page at that offset into a buffer (8) Cast the buffer to a struct mach_header * (9) Look at the magic number: (a) MH_MAGIC - Mach-O 1.0 binary from this architecture (b) MH_MAGIC_64 - Mach-O 2.0 binary from this architecture (c) MH_CIGAM - Mach-O 1.0 binary from PPC/Intel for an Intel/PPC (i) byte swap all Mach-O 1.0 header elements (ii) remember that it is byte-swapped (d) MH_CIGAM_64 - Mach-O 2.0 binary from PPC/Intel for an Intel/PPC (i) byte swap all Mach-O 2.0 header elements (ii) remember that it is byte-swapped (e) Neither - THIS IS NOT AN EXECUTABLE FILE; GIVE UP (10) Iterate the load_command elements following the Mach-O header (i) Byte-swap if necessary, based on having remembered the byte-swap status in step #9 (11) Look for a cmd value of LC_ID_DYLIB (12) Interior to the command section, find the 'name', 'current_version', and 'compatibility_version' (i) Byte-swap the version numbers if necessary, based on having remembered the byte-swap status in step #9 This email sent to site_archiver(a)lists.apple.com

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kernel thread join?
by Duane Murphy 11 Apr '08

11 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com What is the equivalent of pthread_join() for a kernel thread? I am using IOThreadCreate() to create a new thread. At some later point I indicate to that thread to stop. How do I detect that the thread as exited? Thanks, ...Duane _______________________________________________ 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: http://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: Version of dynamic library
by mm w 11 Apr '08

11 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=pOEozQg9vdCfn3577auXMTvND2LCFE3vytThGjCCFpU=; b=qdB6AI+7MATjLaoDXhEJBqlOQcj7Tj3+lI9UhF5ywwhbsNO+bxLP9s/rr9rS2NUmdg6SThdiVEFsBY7VNFvbvMHQEeH2kGSti0+WzvFSJPMmS+rkhSWg4Hv80NPYXhOMcVzmBmokTIiVWuW0wHvPTi64B5B7uY0QQnmQsePSavI= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=G913oS+ZivX0aQyip24rNMehNMrUOAlwuTFZvJf2e3iNx5KGZRdvTTzf7Vg5vMMP8OWyQ5OZLLDOd53u8My3xPHrDIX03C8Z5wMFfaS9b0zdoujyI9EIp3gjya6lxi6i+oJaG3NmHPgETbkM4H11oFQtPy0lPktbrmpeN0heVRI= ok it seems that you want to get the compatibility version and the current version of a shared object? - like otool does? - do you try to determine the version for dlopening it? On Fri, Apr 11, 2008 at 6:31 AM, Graham J Lee <leeg(a)thaesofereode.info> wrote: > On 11 Apr 2008, at 14:13, anukriti_shrimal wrote: > > > > > Now, my problem is that for all fat_arch structs, I am getting cpu_type = > 0 > > or 3. > > But the header file mach/machine.h doen't define 3 or 0 to be valid types. > > My machine is having cpu_type = 7 (x86) and cpu_subtype = 4. > > Since these don't match, I m unable to proceed further. > > > > Hi, > > I can only guess that you're doing it wrong :-(. I've written code to > investigate the content of Mach-O and Mach fat files, and getting the CPU > type information just works. Here are some snippits (some error-checking > and tracing code removed). Getting this into a state where you could use > the code is left as an exercise for the reader... > > Thanks, > Graham. > > - (NSArray *)architectureStrings > { > GLInstanceMethodEntryLog(@"finding architectures"); > int i; > NSMutableArray *strings = [NSMutableArray array]; > for (i = 0; i < header.nfat_arch; i++) > { > struct fat_arch arch = eachFatArch[i]; > NSString *string = MachArchitectureForCpu(arch.cputype, > arch.cpusubtype); > [strings addObject: string]; > } > GLInstanceMethodExitLog(@"copying and returning %@", strings); > return [[strings copy] autorelease]; > } > > - (id)initWithPath: (NSString *)fatFile > { > GLInstanceMethodEntryLog(@"instantiating with path: %@", fatFile); > self = [super init]; > if (self) > { > int fd, bytesRead, fatArchesToRead, i; > NSFileManager *fm = [NSFileManager defaultManager]; > char *cPath = (char *)[fm fileSystemRepresentationWithPath: > fatFile]; > //read the Fat header in > fd = open(cPath, O_RDONLY); > bytesRead = read(fd, &header, sizeof(struct fat_header)); > // do some byteswap > header.magic = NSSwapBigIntToHost(header.magic); > if (header.magic != FAT_MAGIC) > { > GLInstanceMethodExitLog(@"this isn't a Fat file!"); > close(fd); > return nil; > } > header.nfat_arch = NSSwapBigIntToHost(header.nfat_arch); > // read the fat_arch headers in > fatArchesToRead = header.nfat_arch * sizeof(struct > fat_arch); > eachFatArch = malloc(fatArchesToRead); > bytesRead = read(fd, eachFatArch, fatArchesToRead); > close(fd); > // do something with the fat_arch headers > } > return self; > > > } > > _______________________________________________ > 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: > > http://lists.apple.com/mailman/options/darwin-kernel/openspecies%40gmail.com > > This email sent to openspecies(a)gmail.com > -- -mmw _______________________________________________ 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: http://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: Network stack/ethernet driver issues
by Michael Cashwell 11 Apr '08

11 Apr '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Apr 11, 2008, at 9:25 AM, William Kucharski wrote: Michael Cashwell wrote: Happy Friday. -Mike _______________________________________________ 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: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I'd just run across the "UDP == throw-away" mindset in William's post in other contexts (mainly sysadmins configuring routers) and wanted to point out that it's not really correct in all cases. Well, there's a grey area here between what is "correct" and what is allowed. If a particular router or system wanted to pass (being silly here) one UDP packet per hour, it could and wouldn't be violating any of the rules of IP networking. That doesn't mean it's a bad idea to drop those packets, but it's not technically incorrect behavior to do so. Oh yes, absolutely. Systems often have their own policies. Some are boneheaded, but it's their kit. In this particular case, the fact that ring buffer overflow messages are being generated seems indicative that the behavior is not what was intended by the driver authors. The fact that Linux does not display a similar error when run on the same hardware seems to back up this point, but at the same time we don't know what Mac OS X's priorities are when it comes to maintaining isochronous system events. It may have perfectly good reasons it believes it's OK to let the ring buffer overflow. Again, absolutely correct. I wouldn't be surprised if it's a tuning issue to make the graphical UI or Quicktime more responsive or to reduce the amount of wired memory. The error message does very much suggest that the driver writers were expecting to be able to fully handle the hardware, as you say. So there's some disconnect somewhere. Nevertheless, the fact that so much CPU is being consumed to process the UDP packets is pretty much evidence to me that something isn't working the way it was designed, or putting a Mac OS X box on any busy network segment would be enough to bring it to its knees. Indeed. And I'm glad to see the Apple folks strongly request a bug report be entered because it certainly should not have that effect. (Stupid trivia fact: Did you know that dealing with network interrupts is an OLD Mac problem? Back in 1988, putting a Mac II (68020 + PMMU) running A/UX 1.0 or 1.1 on a busy Ethernet network would cause the Mac to first choke then shut off its Ethernet card entirely as it just couldn't handle the traffic properly.) No, hadn't heard about that one. I've done a lot more low-level work on Macs since Mac OS X. Almost none before. I did have fun doing first bring-up of an ATM PCI card on a dual-CPU mirrored G4. My first attempt in testing out interrupts failed to properly clear them and one of the two cores fell to its knees running the ISR continuously. I noted the spike but the system was still working fine so I continued on, found the bug, recompiled and only then rebooted. (I tried to kextunload and not reboot but it was new code and that went down in flames.) A few weeks ago I got an 8-core MacPro and thought "Dual CPUs? Oh how quaint." I spend a lot of time on dual-core laptops but it still amazes me what one can get used to. This email sent to site_archiver(a)lists.apple.com

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