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  • Someone used my postfix smtp (port 25) to send spam mails to me

    - by Andreas
    This week, someone started to send spam-mails through my postfix-smtp access (I verified by logging in through telnet from an arbitrary pc and sending mails with any ids myself) on my server, with recipient and target being [email protected]. Since I have a catchall and mail-fowarding to my google account, I received all those (many) mails. After a lot of configuration (I lost track of what change did what, going through dozends of topics here and over the net) that hole seems fixed. Still, what hapened? Does port 25 need to be open and accepting for my catchall to work? What configuration did I do wrong? I remember the first thing I changed (that had an effect) was the inet_interface setting in main.cf, only later to find out that if this does not say "all", my mail to mydomain.com does not get forwarded any more.

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  • Deny IIS6 web request based on URL parameters?

    - by user21146
    I've got a legacy app running a third-party ecommerce system under IIS6. Some spammers recently discovered a bad security vulnerability in one of the store's forms, which are allowing them to send arbitrary emails from our system. Unfortunately, this store "feature" is built into the default.aspx page's code-behind and I have no way to disable it without shutting down the store. How can I filter out URL request with a given querystring parameter? ie, I want to filter out requests to: http://www.mysite.com/store/?id=SendSpam based on the "SendSpam" string.

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  • Windows program to remove titlebar, frame, etc from a window?

    - by Nelson
    I like playing computer games in windowed mode, as opposed to full screen. I don't like staring at the title bar, frame, and other UI junk. I also don't like seeing other stuff on my desktop around the window. Is there a simple Windows program that will strip the UI chrome off of an arbitrary window from some other application? Extra points for an easy way to put a black screen underneath the window, hiding the desktop. Note: I'm looking specifically to handle windows that are smaller than my desktop size. There's a variety of 'windowed maximized' options that make a window exactly the desktop size, and positioned so all the UI decorations are off screen. (E.g.: ShiftWindow). I'm trying to strip all the decorations away from a window that's smaller than desktop size.

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  • Proxy server modifying request/response upon pass through

    - by jamiei
    I would like to set up a non-transparent proxy server that will selectively modify HTTP requests and responses as it passes them through. The motivation for wanting to modify the data on the fly and not at the original source are not part of the question. I'm hoping there is a solution which allows the modification scripts to be written in a mainstream programming language. I am aware of guides for Squid which allow you to flip images etc on the way through but I was hoping for a slightly more established and less hackish solution. Does anyone know of an established open source project or environment (Any major platform) which would allow me to script in arbitrary modifications to the data being passed through?

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  • a safer no password sudo?

    - by Stacia
    Ok, here's my problem - Please don't yell at me for being insecure! :) This is on my host machine. I'm the only one using it so it's fairly safe, but I have a very complex password that is hard to type over and over. I use the console for moving files around and executing arbitrary commands a LOT, and I switch terminals, so sudo remembering for the console isn't enough (AND I still have to type in my terrible password at least once!) In the past I have used the NOPASSWD trick in sudoers but I've decided to be more secure. Is there any sort of compromise besides allowing no password access to certain apps? (which can still be insecure) Something that will stop malware and remote logins from sudo rm -rf /-ing me, but in my terminals I can type happily away? Can I have this per terminal, perhaps, so just random commands won't make it through? I've tried running the terminal emulations as sudo, but that puts me as root.

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  • PuTTY: how to properly emulate -t option

    - by John Sonderson
    On Linux the ssh command has a -t option whose man page reads: Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine, which can be very useful, e.g. when implementing menu services. Multiple -t options force tty allocate, even if ssh has no local tty. I would like to use this same option with PuTTY on Windows. In particular, I can see that PuTTY has a bunch of options under: Category - Connection - SSH - TTY and suspect it might be possible to achieve the same behavior via some of the (NUMEROUS!) settings found on this screen. Anyone know how to configure the following command: ssh -t USER,[email protected] create Thanks!

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  • Best practices for FQDN for standalone domain (is a two part domain.tld okay?)

    - by birchbark
    I've searched quite a bit and can't seem to find a straight, modern answer on this. If I am hosting a domain, say, mydomain.com, on a machine which is going to solely be used for that domain, and there are no subdomains, is there a real, practical reason besides compliance to create an arbitrary hostname (i.e. myhost) just in order to have a three-part FQDN (myhost.mydomain.com) to satisfy some sort of RFC or convention that's expected. This seems to make a lot of undue complexities from my perspective, and I'm not sure if there's an advantage to this or if it's just a hold-over from a time where all web resources came from a subdomains such as www and ftp which may need to scale to separate machines. I don't use www on my domain, either, which is ill-advised for all I know from an administrators perspective (though removing it is the norm from a designer's perspective)...

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  • Speedup of fixing an openssl bug with 8192 bit key [on hold]

    - by rubo77
    This is related to this Bug-Report https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=747453 OpenSSL contains a set of arbitrary limitations on the size of accepted key parameters that make unrelated software fail to establish secure connections. The problem was found while debugging a XMPP s2s connection issue where two servers with long certificate keys (8192 Bit RSA) failed to establish a secure connection because OpenSSL rejected the handshake. This seems to be a small problem to be fixed but although there is an easy patch available to fix the issue in that bug report, no reactions are noticed so far.. The last patch that broke the 2048 barrier took 2 years to be implemented and only resulted in an increase to 4096bit, which seems to be a bad joke. Where would we have to report this to speed up the implementation for such an issue?

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  • What is a good "free-form" ("type anywhere" or canvas-like) text editor? [on hold]

    - by scorpiodawg
    My 5-1/2 y.o. son is starting to use a computer and one of the things he likes to do is to type stuff into an editor. He has used TuxPaint before and is familiar with the idea of a "canvas" for painting stuff (where painting anything anywhere on the canvas is fair game). When he opened the text editor (this was gedit on Qimo Linux), he attempted to do the same thing -- he pointed the text cursor to an arbitrary location within the editor window and expected to be able to type there (like a "text canvas", if you will). I had to explain to him that he would have to press Enter a few times to create new lines, as well as press Space a few times to create columns before he could do that. This is sub-optimal. My question: are there any free-form, canvas-like text editors that I can have him use? Almost like hex editors of yore. I am not interested in getting him to create "text areas" in a paint program.

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  • How do communcations through ports works

    - by user71866
    I was studying socket programming and certain questions came to my mind. These are some beginner level doubts Is it mandatory to to use well known port for a particular application. For example if i am using ssl, can i design a server to listen on 1000 rather than 443. For http we are connecting to port 80 from some other arbitrary port. Whys no port 80 to port 80 communcation. how a server responds to connections coming to it from different ports to its port 80. how many connections are possible to a particul

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  • getting Error while set up the connection pool in jboss

    - by Yashwant Chavan
    Hi as per following Connection pool configuration facing some issue. Place a copy of mysql-connector-java-[version]-bin.jar in $JBOSS_HOME/server/all/lib. Then, follow the example configuration file named mysql-ds.xml in the $JBOSS_HOME/docs/examples/jca directory that comes with a JBoss binary installation. To activate your DataSource, place an xml file that follows the format of mysql-ds.xml in the deploy subdirectory in either $JBOSS_HOME/server/all, $JBOSS_HOME/server/default, or $JBOSS_HOME/server/[yourconfig] as appropriate. I am getting following error resource-ref: jdbc/buinessCaliberDb has no valid JNDI binding. Check the jboss-web/resource-ref. This is my mysql-ds.xml <datasources> <local-tx-datasource> <jndi-name>jdbc/buinessCaliberDb</jndi-name> <connection-url>jdbc:mysql:///BUSINESS</connection-url> <driver-class>com.mysql.jdbc.Driver</driver-class> <user-name>root</user-name> <password>password</password> <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name> <!-- should only be used on drivers after 3.22.1 with "ping" support <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name> --> <!-- sql to call when connection is created <new-connection-sql>some arbitrary sql</new-connection-sql> --> <!-- sql to call on an existing pooled connection when it is obtained from pool - MySQLValidConnectionChecker is preferred for newer drivers <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql> --> <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) --> <metadata> <type-mapping>mySQL</type-mapping> </metadata> </local-tx-datasource> </datasources> and this my web.xml entry <resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/buinessCaliberDb</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> and this jboss-web.xml entry <jboss-web> <resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/buinessCaliberDb</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> </jboss-web> Please help

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  • Function signature-like expressions as C++ template arguments

    - by Jeff Lee
    I was looking at Don Clugston's FastDelegate mini-library and noticed a weird syntactical trick with the following structure: TemplateClass< void( int, int ) > Object; It almost appears as if a function signature is being used as an argument to a template instance declaration. This technique (whose presence in FastDelegate is apparently due to one Jody Hagins) was used to simplify the declaration of template instances with a semi-arbitrary number of template parameters. To wit, it allowed this something like the following: // A template with one parameter template<typename _T1> struct Object1 { _T1 m_member1; }; // A template with two parameters template<typename _T1, typename _T2> struct Object2 { _T1 m_member1; _T2 m_member2; }; // A forward declaration template<typename _Signature> struct Object; // Some derived types using "function signature"-style template parameters template<typename _Dummy, typename _T1> struct Object<_Dummy(_T1)> : public Object1<_T1> {}; template<typename _Dummy, typename _T1, typename _T2> struct Object<_Dummy(_T1, _T2)> : public Object2<_T1, _T2> {}; // A. "Vanilla" object declarations Object1<int> IntObjectA; Object2<int, char> IntCharObjectA; // B. Nifty, but equivalent, object declarations typedef void UnusedType; Object< UnusedType(int) > IntObjectB; Object< UnusedType(int, char) > IntCharObjectB; // C. Even niftier, and still equivalent, object declarations #define DeclareObject( ... ) Object< UnusedType( __VA_ARGS__ ) > DeclareObject( int ) IntObjectC; DeclareObject( int, char ) IntCharObjectC; Despite the real whiff of hackiness, I find this kind of spoofy emulation of variadic template arguments to be pretty mind-blowing. The real meat of this trick seems to be the fact that I can pass textual constructs like "Type1(Type2, Type3)" as arguments to templates. So here are my questions: How exactly does the compiler interpret this construct? Is it a function signature? Or, is it just a text pattern with parentheses in it? If the former, then does this imply that any arbitrary function signature is a valid type as far as the template processor is concerned? A follow-up question would be that since the above code sample is valid code, why doesn't the C++ standard just allow you to do something like the following, which is does not compile? template<typename _T1> struct Object { _T1 m_member1; }; // Note the class identifier is also "Object" template<typename _T1, typename _T2> struct Object { _T1 m_member1; _T2 m_member2; }; Object<int> IntObject; Object<int, char> IntCharObject;

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  • Slicing a time range into parts

    - by beporter
    First question. Be gentle. I'm working on software that tracks technicians' time spent working on tasks. The software needs to be enhanced to recognize different billable rate multipliers based on the day of the week and the time of day. (For example, "Time and a half after 5 PM on weekdays.") The tech using the software is only required to log the date, his start time and his stop time (in hours and minutes). The software is expected to break the time entry into parts at the boundaries of when the rate multipliers change. A single time entry is not permitted to span multiple days. Here is a partial sample of the rate table. The first-level array keys are the days of the week, obviously. The second-level array keys represent the time of the day when the new multiplier kicks in, and runs until the next sequential entry in the array. The array values are the multiplier for that time range. [rateTable] => Array ( [Monday] => Array ( [00:00:00] => 1.5 [08:00:00] => 1 [17:00:00] => 1.5 [23:59:59] => 1 ) [Tuesday] => Array ( [00:00:00] => 1.5 [08:00:00] => 1 [17:00:00] => 1.5 [23:59:59] => 1 ) ... ) In plain English, this represents a time-and-a-half rate from midnight to 8 am, regular rate from 8 to 5 pm, and time-and-a-half again from 5 till 11:59 pm. The time that these breaks occur may be arbitrary to the second and there can be an arbitrary number of them for each day. (This format is entirely negotiable, but my goal is to make it as easily human-readable as possible.) As an example: a time entry logged on Monday from 15:00:00 (3 PM) to 21:00:00 (9 PM) would consist of 2 hours billed at 1x and 4 hours billed at 1.5x. It is also possible for a single time entry to span multiple breaks. Using the example rateTable above, a time entry from 6 AM to 9 PM would have 3 sub-ranges from 6-8 AM @ 1.5x, 8AM-5PM @ 1x, and 5-9 PM @ 1.5x. By contrast, it's also possible that a time entry may only be from 08:15:00 to 08:30:00 and be entirely encompassed in the range of a single multiplier. I could really use some help coding up some PHP (or at least devising an algorithm) that can take a day of the week, a start time and a stop time and parse into into the required subparts. It would be ideal to have the output be an array that consists of multiple entries for a (start,stop,multiplier) triplet. For the above example, the output would be: [output] => Array ( [0] => Array ( [start] => 15:00:00 [stop] => 17:00:00 [multiplier] => 1 ) [1] => Array ( [start] => 17:00:00 [stop] => 21:00:00 [multiplier] => 1.5 ) ) I just plain can't wrap my head around the logic of splitting a single (start,stop) into (potentially) multiple subparts.

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  • Rendering a Long Document on iPad

    - by benjismith
    I'm implementing a document viewer with highlighting/annotation capabilities for a custom document format on iPad. The documents are kind of long (100 to 200 pages, if printed on paper) and I've had a hard time finding the right approach. Here are the requirments: 1) Basic rich-text styling: control of left/right margins. Control of font name, size, foreground/background color, and line spacing. Bold, italics, underline, etc. 2) Selection and highlighting of arbitrary text regions (not limited to paragraph boundaries, like in Safari/UIWebView). 3) Customization of the Cut/Copy/Paste popup (what is that thing called anyhow? UIActionBar?) This is one of the essential requirements of the app. My first implementation was based on UIWebView. I just rendered the document as HTML with CSS for text styling. But I couldn't get the kind of text selection behavior I wanted (across paragraph boundaries) and the UIActionBar can't be customized from within UIWebView. So I started working on a javascript approach, faking the device text-selection behavior using JQuery to trap touch events and dynamically modifying the DOM to change the background color of selected regions of text. I built a fake UIActionBar control as a hidden DIV, positioning it and unhiding it whenever there was an active selection region. Not too shabby. The main problem is that it's SLOOOOOOOW. Scrolling through the document is nice and quick, but dynamically changing the DOM is not very snappy. Plus, I couldn't figure out how to recreate the magnifier loupe, so my fake text-selection GUI doesn't look quite the same as the native implementation. Also, I haven't yet implemented the communication bridge between the javascript layer and the objective-c layer (where the rest of the app lives), but it was shaping up to be a huge hassle. So I've been looking at CoreText, but there are precious few examples on the web. I spent a little time with this simple little demo: http://github.com/jonasschnelli/I7CoreTextExample/ It shows how to use CoreText to draw an NSAttributedText string into a UIView. But it has its own problems: It doesn't implement text-selection behavior, and it doesn't present a UIActionBar, so I don't have any idea how to make that happen. And, more importantly, it tries to draw the entire document all at once, with significant performance degradations for long documents. My documents can have thousands of paragraphs, and less than 1% of the document is ever on screen at a time. On the plus side, these documents already contain precise formatting information. I know the exact page-position of every line of text, so I don't need a layout engine. Does anyone know how to implement this sort of view using CoreText? I understand that a full-fledged implementation is overkill for a question like this, but I'm looking for a good CoreText example with a few basic requirements: 1) Precise layout & formatting control (using the formatting metrics and text styles I've already calculated). 2) Arbitrary selection of text. 3) Customization of the UIActionBar. 4) Efficient recycling of resources for off-screen objects. I'd be happy to implement my own recycling when text elements scroll off-screen, but wouldn't that require re-implementing UIScrollView? I'm brand-new to iPhone development, and still getting used to Objective-C, but I've been working in other languages (Java, C#, flex/actionscript, etc) for more than ten years, so I feel confident in my ability to get the work done, if only I had a better feel for the iPhone SDK and the common coding patterns for stuff like this. Is it just me, or does the SDK documentation really suck? Anyhow, thanks for your help!

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  • Explicit method tables in C# instead of OO - good? bad?

    - by FunctorSalad
    Hi! I hope the title doesn't sound too subjective; I absolutely do not mean to start a debate on OO in general. I'd merely like to discuss the basic pros and cons for different ways of solving the following sort of problem. Let's take this minimal example: you want to express an abstract datatype T with functions that may take T as input, output, or both: f1 : Takes a T, returns an int f2 : Takes a string, returns a T f3 : Takes a T and a double, returns another T I'd like to avoid downcasting and any other dynamic typing. I'd also like to avoid mutation whenever possible. 1: Abstract-class-based attempt abstract class T { abstract int f1(); // We can't have abstract constructors, so the best we can do, as I see it, is: abstract void f2(string s); // The convention would be that you'd replace calls to the original f2 by invocation of the nullary constructor of the implementing type, followed by invocation of f2. f2 would need to have side-effects to be of any use. // f3 is a problem too: abstract T f3(double d); // This doesn't express that the return value is of the *same* type as the object whose method is invoked; it just expresses that the return value is *some* T. } 2: Parametric polymorphism and an auxilliary class (all implementing classes of TImpl will be singleton classes): abstract class TImpl<T> { abstract int f1(T t); abstract T f2(string s); abstract T f3(T t, double d); } We no longer express that some concrete type actually implements our original spec -- an implementation is simply a type Foo for which we happen to have an instance of TImpl. This doesn't seem to be a problem: If you want a function that works on arbitrary implementations, you just do something like: // Say we want to return a Bar given an arbitrary implementation of our abstract type Bar bar<T>(TImpl<T> ti, T t); At this point, one might as well skip inheritance and singletons altogether and use a 3 First-class function table class /* or struct, even */ TDictT<T> { readonly Func<T,int> f1; readonly Func<string,T> f2; readonly Func<T,double,T> f3; TDict( ... ) { this.f1 = f1; this.f2 = f2; this.f3 = f3; } } Bar bar<T>(TDict<T> td; T t); Though I don't see much practical difference between #2 and #3. Example Implementation class MyT { /* raw data structure goes here; this class needn't have any methods */ } // It doesn't matter where we put the following; could be a static method of MyT, or some static class collecting dictionaries static readonly TDict<MyT> MyTDict = new TDict<MyT>( (t) => /* body of f1 goes here */ , // f2 (s) => /* body of f2 goes here */, // f3 (t,d) => /* body of f3 goes here */ ); Thoughts? #3 is unidiomatic, but it seems rather safe and clean. One question is whether there are any performance concerns with it. I don't usually need dynamic dispatch, and I'd prefer if these function bodies get statically inlined in places where the concrete implementing type is known statically. Is #2 better in that regard?

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  • Javascript style objects in Objective-C

    - by awolf
    Background: I use a ton of NSDictionary objects in my iPhone and iPad code. I'm sick of the verbose way of getting/setting keys to these state dictionaries. So a little bit of an experiment: I just created a class I call Remap. Remap will take any arbitrary set[VariableName]:(NSObject *) obj selector and forward that message to a function that will insert obj into an internal NSMutableDictionary under the key [vairableName]. Remap will also take any (zero argument) arbitrary [variableName] selector and return the NSObject mapped in the NSMutableDictionary under the key [variableName]. e.g. Remap * remap = [[Remap alloc] init]; NSNumber * testNumber = [NSNumber numberWithInt:46]; [remap setTestNumber:testNumber]; testNumber = [remap testNumber]; [remap setTestString:@"test string"]; NSString * testString = [remap testString]; NSMutableDictionary * testDict = [NSMutableDictionary dictionaryWithObject:testNumber forKey:@"testNumber"]; [remap setTestDict:testDict]; testDict = [remap testDict]; where none of the properties testNumber, testString, or testDict are actually defined in Remap. The crazy thing? It works... My only question is how can I disable the "may not respond to " warnings for JUST accesses to Remap? P.S. : I'll probably end up scrapping this and going with macros since message forwarding is quite inefficient... but aside from that does anyone see other problems with Remap? Here's Remap's .m for those who are curious: #import "Remap.h" @interface Remap () @property (nonatomic, retain) NSMutableDictionary * _data; @end @implementation Remap @synthesize _data; - (void) dealloc { relnil(_data); [super dealloc]; } - (id) init { self = [super init]; if (self != nil) { NSMutableDictionary * dict = [[NSMutableDictionary alloc] init]; [self set_data:dict]; relnil(dict); } return self; } - (void)forwardInvocation:(NSInvocation *)anInvocation { NSString * selectorName = [NSString stringWithUTF8String: sel_getName([anInvocation selector])]; NSRange range = [selectorName rangeOfString:@"set"]; NSInteger numArguments = [[anInvocation methodSignature] numberOfArguments]; if (range.location == 0 && numArguments == 4) { //setter [anInvocation setSelector:@selector(setData:withKey:)]; [anInvocation setArgument:&selectorName atIndex:3]; [anInvocation invokeWithTarget:self]; } else if (numArguments == 3) { [anInvocation setSelector:@selector(getDataWithKey:)]; [anInvocation setArgument:&selectorName atIndex:2]; [anInvocation invokeWithTarget:self]; } } - (NSMethodSignature *) methodSignatureForSelector:(SEL) aSelector { NSString * selectorName = [NSString stringWithUTF8String: sel_getName(aSelector)]; NSMethodSignature * sig = [super methodSignatureForSelector:aSelector]; if (sig == nil) { NSRange range = [selectorName rangeOfString:@"set"]; if (range.location == 0) { sig = [self methodSignatureForSelector:@selector(setData:withKey:)]; } else { sig = [self methodSignatureForSelector:@selector(getDataWithKey:)]; } } return sig; } - (NSObject *) getDataWithKey: (NSString *) key { NSObject * returnValue = [[self _data] objectForKey:key]; return returnValue; } - (void) setData: (NSObject *) data withKey:(NSString *)key { if (key && [key length] >= 5 && data) { NSRange range; range.length = 1; range.location = 3; NSString * firstChar = [key substringWithRange:range]; firstChar = [firstChar lowercaseString]; range.length = [key length] - 5; // the 4 we have processed plus the training : range.location = 4; NSString * adjustedKey = [NSString stringWithFormat:@"%@%@", firstChar, [key substringWithRange:range]]; [[self _data] setObject:data forKey:adjustedKey]; } else { //assert? } } @end

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  • XNA: Camera's Rotation and Translation matrices seem to interfere with each other

    - by Danjen
    I've been following the guide here for how to create a custom 2D camera in XNA. It works great, I've implemented it before, but for some reason, the matrix math is throwing me off. public sealed class Camera2D { public Vector2 Origin { get; set; } public Vector2 Position { get; set; } public float Scale { get; set; } public float Rotation { get; set; } } It might be easier to just show you a picture of my problem: http://i.imgur.com/H1l6LEx.png What I want to do is allow the camera to pivot around any given point. Right now, I have the rotations mapped to my shoulder buttons on a gamepad, and if I press them, it should rotate around the point the camera is currently looking at. Then, I use the left stick to move the camera around. The problem is that after it's been rotated, pressing "up" results in it being used relative to the rotation, creating the image above. I understand that matrices have to be applied in a certain order, and that I have to offset the thing to be rotated around the world origin and move it back, but it just won't work! public Matrix GetTransformationMatrix() { Matrix mRotate = Matrix.Identity * Matrix.CreateTranslation(-Origin.X, -Origin.Y, 0.00f) * // Move origin to world center Matrix.CreateRotationZ(MathHelper.ToRadians(Rotation)) * // Apply rotation Matrix.CreateTranslation(+Origin.X, +Origin.Y, 0.00f); // Undo the move operation Matrix mTranslate = Matrix.Identity * Matrix.CreateTranslation(-Position.X, Position.Y, 0.00f); // Apply the actual translation return mRotate * mTranslate; } So to recap, it seems I can have it rotate around an arbitrary point and lose the ability to have "up" move the camera straight up, or I can rotate it around the world origin and have the camera move properly, but not both.

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  • Entity Framework Code-First to Provide Replacement for ASP.NET Profile Provider

    - by Ken Cox [MVP]
    A while back, I coordinated a project to add support for the SQL Table Profile Provider in ASP.NET 4 Web Applications.  We urged Microsoft to improve ASP.NET’s built-in Profile support so our workaround wouldn’t be necessary. Instead, Microsoft plans to provide a replacement for ASP.NET Profile in a forthcoming release. In response to my feature suggestion on Connect, Microsoft says we should look for something even better using Entity Framework: “When code-first is officially released the final piece of a full replacement of the ASP.NET Profile will have arrived. Once code-first for EF4 is released, developers will have a really easy and very approachable way to create any arbitrary class, and automatically have the .NET Framework create a table to provide storage for that class. Furthermore developer will also have full LINQ-query capabilities against code-first classes. “ The downside is that there won’t be a way to retrofit this Profile replacement to pre- ASP.NET 4 Web applications. At least there’ll still be the MVP workaround code. It looks like it’s time for me to dig into a CTP of EF Code-First to see what’s available.   Scott Guthrie has been blogging about Code-First Development with Entity Framework 4. It’s not clear when the EF Code-First is coming, but my guess is that it’ll be part of the VS 2010/.NET 4 service pack.

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  • Step by Step Install of MAAS and JUJU

    - by John S
    I am working on understanding the pieces that I am missing in being able to deploy Juju across the other MAAS nodes. I don't know If I have a step out of place, or missing a few. The server owns the router which handles the DHCP and DNS. Any assistance is greatly appreciated. When I am at the end I will either get a 409 error, or arbitrary pick tools 1.16.0 error. It is worth mentioning that local, and aws works fine. Hopefully with all of these steps spelled out it will help someone else along the way too. Steps Setting Up MAAS and JUJU - 12.04 LTS Clean install SSH only from the package selection during install sudo apt-get install software-properties-common sudo apt-get install python-software-properties sudo add-apt-repository ppa:maas-maintainers/stable sudo add-apt-repository ppa:juju/stable sudo apt-get update sudo apt-get dist-upgrade sudo reboot sudo apt-get install maas maas-dns maas-dhcp sudo ufw disable sudo reboot - edit /etc/dhcp/dhcpd.conf authoritive subnet 10.0.0.0 netmask 255.255.255.0 { next-server 10.0.0.2; filename "pxelinux.0"; } sudo maas createsuperuser sudo maas-import-pxe-files Login to MAAS http://10.x.x.x/MAAS cluster controller configuration for eth0 manage dhcp and dns IP 10.0.0.2 subnet 255.255.255.0 broadcast 10.0.0.0 routerip 10.0.0.1 ip low 10.0.0.5 ip high 10.0.0.180 Commissioning default and distro is set at 12.04 default domain is at local sudo maas-cli login maas http://10.x.x.x/MAAS/api/1.0 api-key ssh-keygen -t rsa -b 2048 - enter - no password - cat id_rsa.pub and enter key into MAAS ssh sudo maas-cli maas nodes accept-all (interestingly enough I only get back [] when executing this ) PXE one machine, accept and commision, start and deploy. sudo apt-get install juju-core juju-local MAAS config: maas: type: maas maas-server: '://10.x.x.x:80/MAAS' maas-oauth: 'MAAS_API_KEY' admin-secret: 'nothing' default-series: 'precise' juju switch maas sudo juju bootstrap --show-log

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  • Optimizing Solaris 11 SHA-1 on Intel Processors

    - by danx
    SHA-1 is a "hash" or "digest" operation that produces a 160 bit (20 byte) checksum value on arbitrary data, such as a file. It is intended to uniquely identify text and to verify it hasn't been modified. Max Locktyukhin and others at Intel have improved the performance of the SHA-1 digest algorithm using multiple techniques. This code has been incorporated into Solaris 11 and is available in the Solaris Crypto Framework via the libmd(3LIB), the industry-standard libpkcs11(3LIB) library, and Solaris kernel module sha1. The optimized code is used automatically on systems with a x86 CPU supporting SSSE3 (Intel Supplemental SSSE3). Intel microprocessor architectures that support SSSE3 include Nehalem, Westmere, Sandy Bridge microprocessor families. Further optimizations are available for microprocessors that support AVX (such as Sandy Bridge). Although SHA-1 is considered obsolete because of weaknesses found in the SHA-1 algorithm—NIST recommends using at least SHA-256, SHA-1 is still widely used and will be with us for awhile more. Collisions (the same SHA-1 result for two different inputs) can be found with moderate effort. SHA-1 is used heavily though in SSL/TLS, for example. And SHA-1 is stronger than the older MD5 digest algorithm, another digest option defined in SSL/TLS. Optimizations Review SHA-1 operates by reading an arbitrary amount of data. The data is read in 512 bit (64 byte) blocks (the last block is padded in a specific way to ensure it's a full 64 bytes). Each 64 byte block has 80 "rounds" of calculations (consisting of a mixture of "ROTATE-LEFT", "AND", and "XOR") applied to the block. Each round produces a 32-bit intermediate result, called W[i]. Here's what each round operates: The first 16 rounds, rounds 0 to 15, read the 512 bit block 32 bits at-a-time. These 32 bits is used as input to the round. The remaining rounds, rounds 16 to 79, use the results from the previous rounds as input. Specifically for round i it XORs the results of rounds i-3, i-8, i-14, and i-16 and rotates the result left 1 bit. The remaining calculations for the round is a series of AND, XOR, and ROTATE-LEFT operators on the 32-bit input and some constants. The 32-bit result is saved as W[i] for round i. The 32-bit result of the final round, W[79], is the SHA-1 checksum. Optimization: Vectorization The first 16 rounds can be vectorized (computed in parallel) because they don't depend on the output of a previous round. As for the remaining rounds, because of step 2 above, computing round i depends on the results of round i-3, W[i-3], one can vectorize 3 rounds at-a-time. Max Locktyukhin found through simple factoring, explained in detail in his article referenced below, that the dependencies of round i on the results of rounds i-3, i-8, i-14, and i-16 can be replaced instead with dependencies on the results of rounds i-6, i-16, i-28, and i-32. That is, instead of initializing intermediate result W[i] with: W[i] = (W[i-3] XOR W[i-8] XOR W[i-14] XOR W[i-16]) ROTATE-LEFT 1 Initialize W[i] as follows: W[i] = (W[i-6] XOR W[i-16] XOR W[i-28] XOR W[i-32]) ROTATE-LEFT 2 That means that 6 rounds could be vectorized at once, with no additional calculations, instead of just 3! This optimization is independent of Intel or any other microprocessor architecture, although the microprocessor has to support vectorization to use it, and exploits one of the weaknesses of SHA-1. Optimization: SSSE3 Intel SSSE3 makes use of 16 %xmm registers, each 128 bits wide. The 4 32-bit inputs to a round, W[i-6], W[i-16], W[i-28], W[i-32], all fit in one %xmm register. The following code snippet, from Max Locktyukhin's article, converted to ATT assembly syntax, computes 4 rounds in parallel with just a dozen or so SSSE3 instructions: movdqa W_minus_04, W_TMP pxor W_minus_28, W // W equals W[i-32:i-29] before XOR // W = W[i-32:i-29] ^ W[i-28:i-25] palignr $8, W_minus_08, W_TMP // W_TMP = W[i-6:i-3], combined from // W[i-4:i-1] and W[i-8:i-5] vectors pxor W_minus_16, W // W = (W[i-32:i-29] ^ W[i-28:i-25]) ^ W[i-16:i-13] pxor W_TMP, W // W = (W[i-32:i-29] ^ W[i-28:i-25] ^ W[i-16:i-13]) ^ W[i-6:i-3]) movdqa W, W_TMP // 4 dwords in W are rotated left by 2 psrld $30, W // rotate left by 2 W = (W >> 30) | (W << 2) pslld $2, W_TMP por W, W_TMP movdqa W_TMP, W // four new W values W[i:i+3] are now calculated paddd (K_XMM), W_TMP // adding 4 current round's values of K movdqa W_TMP, (WK(i)) // storing for downstream GPR instructions to read A window of the 32 previous results, W[i-1] to W[i-32] is saved in memory on the stack. This is best illustrated with a chart. Without vectorization, computing the rounds is like this (each "R" represents 1 round of SHA-1 computation): RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR With vectorization, 4 rounds can be computed in parallel: RRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRRRR Optimization: AVX The new "Sandy Bridge" microprocessor architecture, which supports AVX, allows another interesting optimization. SSSE3 instructions have two operands, a input and an output. AVX allows three operands, two inputs and an output. In many cases two SSSE3 instructions can be combined into one AVX instruction. The difference is best illustrated with an example. Consider these two instructions from the snippet above: pxor W_minus_16, W // W = (W[i-32:i-29] ^ W[i-28:i-25]) ^ W[i-16:i-13] pxor W_TMP, W // W = (W[i-32:i-29] ^ W[i-28:i-25] ^ W[i-16:i-13]) ^ W[i-6:i-3]) With AVX they can be combined in one instruction: vpxor W_minus_16, W, W_TMP // W = (W[i-32:i-29] ^ W[i-28:i-25] ^ W[i-16:i-13]) ^ W[i-6:i-3]) This optimization is also in Solaris, although Sandy Bridge-based systems aren't widely available yet. As an exercise for the reader, AVX also has 256-bit media registers, %ymm0 - %ymm15 (a superset of 128-bit %xmm0 - %xmm15). Can %ymm registers be used to parallelize the code even more? Optimization: Solaris-specific In addition to using the Intel code described above, I performed other minor optimizations to the Solaris SHA-1 code: Increased the digest(1) and mac(1) command's buffer size from 4K to 64K, as previously done for decrypt(1) and encrypt(1). This size is well suited for ZFS file systems, but helps for other file systems as well. Optimized encode functions, which byte swap the input and output data, to copy/byte-swap 4 or 8 bytes at-a-time instead of 1 byte-at-a-time. Enhanced the Solaris mdb(1) and kmdb(1) debuggers to display all 16 %xmm and %ymm registers (mdb "$x" command). Previously they only displayed the first 8 that are available in 32-bit mode. Can't optimize if you can't debug :-). Changed the SHA-1 code to allow processing in "chunks" greater than 2 Gigabytes (64-bits) Performance I measured performance on a Sun Ultra 27 (which has a Nehalem-class Xeon 5500 Intel W3570 microprocessor @3.2GHz). Turbo mode is disabled for consistent performance measurement. Graphs are better than words and numbers, so here they are: The first graph shows the Solaris digest(1) command before and after the optimizations discussed here, contained in libmd(3LIB). I ran the digest command on a half GByte file in swapfs (/tmp) and execution time decreased from 1.35 seconds to 0.98 seconds. The second graph shows the the results of an internal microbenchmark that uses the Solaris libpkcs11(3LIB) library. The operations are on a 128 byte buffer with 10,000 iterations. The results show operations increased from 320,000 to 416,000 operations per second. Finally the third graph shows the results of an internal kernel microbenchmark that uses the Solaris /kernel/crypto/amd64/sha1 module. The operations are on a 64Kbyte buffer with 100 iterations. third graph shows the results of an internal kernel microbenchmark that uses the Solaris /kernel/crypto/amd64/sha1 module. The operations are on a 64Kbyte buffer with 100 iterations. The results show for 1 kernel thread, operations increased from 410 to 600 MBytes/second. For 8 kernel threads, operations increase from 1540 to 1940 MBytes/second. Availability This code is in Solaris 11 FCS. It is available in the 64-bit libmd(3LIB) library for 64-bit programs and is in the Solaris kernel. You must be running hardware that supports Intel's SSSE3 instructions (for example, Intel Nehalem, Westmere, or Sandy Bridge microprocessor architectures). The easiest way to determine if SSSE3 is available is with the isainfo(1) command. For example, nehalem $ isainfo -v $ isainfo -v 64-bit amd64 applications sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov amd_sysc cx8 tsc fpu 32-bit i386 applications sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov sep cx8 tsc fpu If the output also shows "avx", the Solaris executes the even-more optimized 3-operand AVX instructions for SHA-1 mentioned above: sandybridge $ isainfo -v 64-bit amd64 applications avx xsave pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov amd_sysc cx8 tsc fpu 32-bit i386 applications avx xsave pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov sep cx8 tsc fpu No special configuration or setup is needed to take advantage of this code. Solaris libraries and kernel automatically determine if it's running on SSSE3 or AVX-capable machines and execute the correctly-tuned code for that microprocessor. Summary The Solaris 11 Crypto Framework, via the sha1 kernel module and libmd(3LIB) and libpkcs11(3LIB) libraries, incorporated a useful SHA-1 optimization from Intel for SSSE3-capable microprocessors. As with other Solaris optimizations, they come automatically "under the hood" with the current Solaris release. References "Improving the Performance of the Secure Hash Algorithm (SHA-1)" by Max Locktyukhin (Intel, March 2010). The source for these SHA-1 optimizations used in Solaris "SHA-1", Wikipedia Good overview of SHA-1 FIPS 180-1 SHA-1 standard (FIPS, 1995) NIST Comments on Cryptanalytic Attacks on SHA-1 (2005, revised 2006)

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  • NLP - Queries using semantic wildcards in full text searching, maybe with Lucene?

    - by Zsolt
    Let's say I have a big corpus (for example in english or an arbitrary language), and I want to perform some semantic search on it. For example I have the query: "Be careful: [art] armada of [sg] is coming to [do sg]!" And the corpus contains the following sentence: "Be careful: an armada of alien ships is coming to destroy our planet!" It can be seen that my query string could contain "semantic placeholders", such as: [art] - some placeholder for articles (for example a / an in English) [sg], [do sg] - some placeholders for NPs and VPs (subjects and predicates) I would like to develop a library which would be capable to handle these queries efficiently. I suspect that some kind of POS-tagging would be necessary for parsing the text, but because I don't want to fully reimplement an already existing full-text search engine to make it work, I'm considering that how could I integrate this behaviour into a search engine like Lucene? I know there are SpanQueries which could behave similarly in some cases, but as I can see, Lucene doesn't do any semantic stuff with stored texts. It is possible to implement a behavior like this? Or do I have to write an own search engine?

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  • Dell Docking Station Doesn’t Detect USB Mouse and Keyboard

    - by Ben Griswold
    I’ve found myself in this situation with multiple Dell docking stations and multiple Dell laptops running various Windows operating systems.  I don’t know why the docking station stops recognizing my USB mouse and keyboard – it just does.  It’s black magic.  The last time around I just starting plugging the mouse and keyboard into the docked laptop directly and went about my business (as if I wasn’t completing missing out on a couple of the core benefits of using a docking station.)  I guess that’s what happens when you forget how you got yourself out of the mess the last time around.  I had been in this half-assed state for a couple of weeks now, but a coworker fortunately got themselves in and out of the same pickle this morning.  Procrastinate long enough and the solution will just come to you, right? Here’s how to get yourself out of this mess: Undock your computer Unplug your docking station Count to an arbitrary number greater than 12.  (Not sure this is really required, but…) Plug your docking station back in Redock your machine I put my machine to sleep before taking the aforementioned actions.  My coworker completely shutdown his laptop instead.  The steps worked on both of our Win 7 machines this morning and, who knows, it might just work for you too. 

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  • Java - System design with distributed Queues and Locks

    - by sunny
    Looking for inputs to evaluate a design for a system (java) which would have a distributed queue serving several (but not too many) nodes. These nodes would process objects present in the distributed queue and on occasion require a distributed lock across the cluster on an arbitrary (distributed) data structures. These (distributed) data structures could potentially lie in a distributed cache. Eliminating Terracotta (DSO),Hazelcast and Akka what could be alternative choices. Currently considering zookeeper as a distributed locking mechanism. Since the recommendation of a znode is not to exceed the 1M size , the understanding is that zookeeper should not be used a distributed queue. And also from Netflix curator tech note 4. So should a distributed cache, say like memcached, or redis be used to emulate a distributed queue ? i.e. The distributed queue will be stored in the caches and will be locked cluster-wide via zookeeper. Are there potential pitfalls with this high-level approach. The objects don't need to be taken off the queue. The object will pass through a lifecycle which will determine its removal from the queue. There would be about 10k+ objects in a queue at a given time changing states and any node could service one stage of the object's lifecycle. (Although not strictly necessary .. i.e. one node could serve the entire lifecycle if that is more efficient.) Any suggestions/alternatives ? sidenote: new to zookeeper ; redis etc.

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  • Document-oriented vs Column-oriented database fit

    - by user1007922
    I have a data-intensive application that desperately needs a database make-over. The general data model: There are records with RIDs, grouped together by group IDs (GID). The records have arbitrary data fields, (maybe 5-15) with a few of them mandatory and the rest optional, and thus sparse. The general use model: There are LOTS and LOTS of Writes. Millions to Billions of records are stored. Very often, they are associated with new GIDs, but sometimes, they are associated with existing GIDs. There aren't as many reads, but when they happen, they need to be pretty fast or at least constant speed regardless of the database size. And when the reads happen, it will need to retrieve all the records/RIDs with a certain GID. I don't have a need to search by the record field values. Primarily, I will need to query by the GID and maybe RID. What database implementation should I use? I did some initial research between document-oriented and column-oriented databases and it seems the document-oriented ones are a good fit, model-wise. I could store all the records together under the same document key using the GID. But I don't really have any use for their ability to search the document contents itself. I like the simplicity and scalability of column-oriented databases like Cassandra, but how should I model my data in this paradigm for optimal performance? Should my key be the GID and should I create a column for each record/RID? (there maybe thousands or hundreds of thousands of records in a group/GID). Or should my key be the RID and ensure each row has a column for the GID value? What results in faster writes and reads under this model?

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  • Enum.HasFlag

    - by Scott Dorman
    An enumerated type, also called an enumeration (or just an enum for short), is simply a way to create a numeric type restricted to a predetermined set of valid values with meaningful names for those values. While most enumerations represent discrete values, or well-known combinations of those values, sometimes you want to combine values in an arbitrary fashion. These enumerations are known as flags enumerations because the values represent flags which can be set or unset. To combine multiple enumeration values, you use the logical OR operator. For example, consider the following: public enum FileAccess { None = 0, Read = 1, Write = 2, }   class Program { static void Main(string[] args) { FileAccess access = FileAccess.Read | FileAccess.Write; Console.WriteLine(access); } } The output of this simple console application is: The value 3 is the numeric value associated with the combination of FileAccess.Read and FileAccess.Write. Clearly, this isn’t the best representation. What you really want is for the output to look like: To achieve this result, you simply add the Flags attribute to the enumeration. The Flags attribute changes how the string representation of the enumeration value is displayed when using the ToString() method. Although the .NET Framework does not require it, enumerations that will be used to represent flags should be decorated with the Flags attribute since it provides a clear indication of intent. One “problem” with Flags enumerations is determining when a particular flag is set. The code to do this isn’t particularly difficult, but unless you use it regularly it can be easy to forget. To test if the access variable has the FileAccess.Read flag set, you would use the following code: (access & FileAccess.Read) == FileAccess.Read Starting with .NET 4, a HasFlag static method has been added to the Enum class which allows you to easily perform these tests: access.HasFlag(FileAccess.Read) This method follows one of the “themes” for the .NET Framework 4, which is to simplify and reduce the amount of boilerplate code like this you must write. Technorati Tags: .NET,C# 4

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