site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Importance: Normal Hi, I'm trying to implement Filter Scheme using "Sample Filter Scheme" from the Apple's documentation. My driver is successfully loaded, creating a Volume for the partition I created with hdiutil. At this stage I want just to process a content of a buffer in my driver's read()/write() methods. In both methods I allocate a temporary char *myBuff of IOMemoryDescriptor* buffer->getLength() size, pass it to byffer->readBytes() and then send myBuff to IOLog() method that prints it to /var/log/system.log. It works for getProvider()->write() but it shows also the data which is not a content of a file. It DOESN'T work at all for getProvider()->read(). QUESTION 1: Why getProvider()->read() doesn't bring the file data at all? ------------------------------------------------------------------------- It seems that getProvider()->read() doesn't work, since calling buffer->readBytes() in read() before (for debug only) and after getProvider()->read() gives the same junk in myBuff. What is wrong with my read() method? QUESTION 2: How can I know what data is read/written with getProvider()->read/write() ? ---------------------------------------------------------------------------- ----------- IOLog() shows that read/write() receives some strange data which is not a file content. How can I know what data contains buffer? Following is the source code of my read() and write() methods. Any help will be appreciated. Thanks in advance! // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - void com_MyTutorial_driver_MyFilterscheme::read(IOService* /* client */, UInt64 byteStart, IOMemoryDescriptor* buffer, IOStorageCompletion completion) { IOByteCount readBytes; IOByteCount bufLength = buffer->getLength(); char *myBuff = new char[bufLength]; readBytes = buffer->readBytes(0, myBuff, bufLength); IOLog("MyFilterscheme::read BEFORE*** readBytes = %lu byteStart = %lu bufLength = %lu buffer = %s ***\n", (long)readBytes, (long)byteStart, (long)bufLength, myBuff); getProvider()->read(this, byteStart, buffer, completion); readBytes = buffer->readBytes(0, myBuff, bufLength); for (IOByteCount i = 0; i < bufLength - 1; i++) { if (myBuff [i] == 't') if (myBuff [i+1] == 'e') IOLog("MyFilterscheme::read ***FOUND*** buffer @ %lu = %s ***\n", (long)i, myBuff + i); } IOLog("MyFilterscheme::read AFTER *** readBytes = %lu byteStart = %lu bufLength = %lu buffer = %s ***\n", (long)readBytes, (long)byteStart, (long)bufLength, myBuff); delete[] myBuff; } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - void com_MyTutorial_driver_MyFilterscheme::write(IOService* /* client */, UInt64 byteStart, IOMemoryDescriptor* buffer, IOStorageCompletion completion) { IOByteCount readBytes; IOByteCount bufLength = buffer->getLength(); char *myBuff = new char[bufLength]; readBytes = buffer->readBytes(0, myBuff, bufLength); IOLog("MyFilterscheme::write readBytes = %lu byteStart = %lu bufLength = %lu buffer = %s ***\n", (long)readBytes, (long)byteStart, (long)bufLength, myBuff); getProvider()->write(this, byteStart, buffer, completion); delete[] myBuff; } _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... This email sent to site_archiver@lists.apple.com