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  • malloc:mmap(size=XX) failed (error code=12)

    - by Michel
    I have a memory problem in an iPhone app, giving me a hard time. Here is the error message I get: malloc: * mmap(size=9281536) failed (error code=12) * error: can't allocate region I am using ARC for this app, in case that might be useful information. The code (below) is just using a file in the Bundle in order to load a core data entity. The strange thing is the crash happens only after more than 90 loops; while it seems to mee that since the size of the "contents" in getting smaller and smaller, the memory request should also get smaller and smaller. Here is the code, if any one can see a flaw please let me know. NSString *path,*contents,*lineBuffer; path=[[NSBundle mainBundle] pathForResource:@"myFileName" ofType:@"txt"]; contents=[NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil]; int counter=0; while (counter<10000) { lineBuffer=[contents substringToIndex:[contents rangeOfCharacterFromSet:[NSCharacterSet newlineCharacterSet]].location]; contents=[contents substringFromIndex:[lineBuffer length]+1]; newItem=[NSEntityDescription insertNewObjectForEntityForName:@"myEntityName" inManagedObjectContext:context]; [newItem setValue:lineBuffer forKey:@"name"]; request=[[NSFetchRequest alloc] init]; [request setEntity: [NSEntityDescription entityForName:@"myEntityName" inManagedObjectContext:context]]; error=nil; [context save:&error]; counter++; }

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  • Execute client & server side code with one click?

    - by Abu Hamzah
    i am not sure if my design have flaw but would like to know what others have to say, i am in a situation where i am trying to acheive two things in one click. using : asp.net web form i have a web form with few textbox and a gridview control and a button. if i click on the button i am executing two things 1) asynchronously get data from server to client (working great) and able to display the data in the textboxes. 2) same click i want to bind the gridview. <asp:Content ID="Content2" ContentPlaceHolderID="cphMaster" runat="server"> <asp:Label runat="server" ID='Label1' >Id:</asp:Label> <asp:TextBox ID="txtId" runat='server'></asp:TextBox> <asp:Button ID="btnSubmit" OnClientClick="LoadDataById();" runat="server" Text="Submit" onclick="btnSubmit_Click" /> <br /> <br /> <asp:TextBox ID="txtName" runat='server'></asp:TextBox> <br /> <asp:TextBox ID="txtPurpose" runat='server'></asp:TextBox> <br /> <br /> <asp:GridView ID="GridView1" runat="server"> </asp:GridView> </asp:Content> server side protected void btnSubmit_Click(object sender, EventArgs e) { GridView1.DataSource = laodData(int.Parse(txtId.Text)); GridView1.DataBind(); } Jquery: function LoadVisitBasicByVisitId() { ContactServiceProxy.invoke({ serviceMethod: "GetDataById", data: { request: request }, callback: function(response) { processCompletedContactStore(response); }, error: function(xhr, errorMsg, thrown) { postErrorAndUnBlockUI(xhr, errorMsg, thrown); } }); return false; } recap: 1) jquery script execute asynchronously to get data from server to client and display in the textboxes 2) server side code to bind the gridview.

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  • PHP & MySQL username validation and storage problem.

    - by php
    For some reason when a user enters a brand new username the error message <p>Username unavailable</p> is displayed and the name is not stored. I was wondering if some can help find the flaw in my code so I can fix this error? Thanks Here is the PHP code. if($_POST['username'] && trim($_POST['username'])!=='') { $u = "SELECT * FROM users WHERE username = '$username' AND user_id <> '$user_id'"; $r = mysqli_query ($mysqli, $u) or trigger_error("Query: $u\n<br />MySQL Error: " . mysqli_error($mysqli)); if (mysqli_num_rows($r) == TRUE) { echo '<p>Username unavailable</p>'; $_POST['username'] = NULL; } else if(isset($_POST['username']) && mysqli_num_rows($r) == 0 && strlen($_POST['username']) <= 255) { $username = mysqli_real_escape_string($mysqli, $_POST['username']); } else if($_POST['username'] && strlen($_POST['username']) >= 256) { echo '<p>Username can not exceed 255 characters</p>'; } }

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  • SLRequest return nil before block complete

    - by jaytr0n
    I'm having a little trouble thinking through this and deciding if it's a design flaw on my behalf or if I'm missing a piece that could make this work. Basically I'm using the new SLRequest to make a Twitter API call. After the data is returned, I'd like to put it into an object and return that object: -(AUDSlide *) getFollowerSlide { SLRequest *getRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodGET URL:[NSURL URLWithString:[NSString stringWithFormat:@"https://api.twitter.com/1.1/followers/ids.json?user_id=%@", [[self.twitterAccount valueForKey:@"properties"] valueForKey:@"user_id"]]] parameters:nil]; getRequest.account = twitterAccount; AUDSlide *slide = [[AUDSlide alloc] init]; [getRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) { if ([urlResponse statusCode] == 200) { NSError *jsonError = nil; NSDictionary *list = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:&jsonError]; NSLog(@"Number of Followers: %u", [[list objectForKey:@"ids"] count]); slide.title = @"Followers"; slide.number = [NSString stringWithFormat:@"%u",[[list objectForKey:@"ids"] count]]; } else{ slide.title = @"Error"; slide.number = [NSString stringWithFormat: @"E%u", [urlResponse statusCode]]; } }]; return slide; } Of course the slide is returned before the call is complete and returns a nil object. So I'm not sure if I should try to force this into a synchronous request (that seems like it could be a bad idea) or rethink the design. Does anyone have any advice?

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  • Need help finding a unique value in array

    - by bardockyo
    My code is complete minus one little flaw. It searches the array and prints out which values are unique, however it always counts the first entry as unique even if it is followed by the same value. Can anyone look at my code and tell me which part is messing this up because it is driving me crazy. #include <stdio.h> #define size 7 int main(void) { int array1[size], target, answer, found, x, k, prev, count =1, i; printf("Please input %d integers: ", size); scanf("%d", &target); for(x = 0; x < size; x++) { scanf("%d", &array1[x]); } prev = array1[0]; for (i = 1; i < size; i++) { if (array1[i] == prev) { count++; } else { if (count < 2) printf("%d=%d\n", prev, count); prev = array1[i]; count = 1; } } if (count < 2) { printf("%d=%d\n", prev, count); } return 0; }

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  • How to make Shared Keys .ssh/authorized_keys and sudo work together?

    - by farinspace
    I've setup the .ssh/authorized_keys and am able to login with the new "user" using the pub/private key ... I have also added "user" to the sudoers list ... the problem I have now is when I try to execute a sudo command, something simple like: $ sudo cd /root it will prompt me for my password, which I enter, but it doesn't work (I am using the private key password I set) Also, ive disabled the users password using $ passwd -l user What am I missing? Somewhere my initial remarks are being misunderstood ... I am trying to harden my system ... the ultimate goal is to use pub/private keys to do logins versus simple password authentication. I've figured out how to set all that up via the authorized_keys file. Additionally I will ultimately prevent server logins through the root account. But before I do that I need sudo to work for a second user (the user which I will be login into the system with all the time). For this second user I want to prevent regular password logins and force only pub/private key logins, if I don't lock the user via" passwd -l user ... then if i dont use a key, i can still get into the server with a regular password. But more importantly I need to get sudo to work with a pub/private key setup with a user whos had his/her password disabled. Edit: Ok I think I've got it (the solution): 1) I've adjusted /etc/ssh/sshd_config and set PasswordAuthentication no This will prevent ssh password logins (be sure to have a working public/private key setup prior to doing this 2) I've adjusted the sudoers list visudo and added root ALL=(ALL) ALL dimas ALL=(ALL) NOPASSWD: ALL 3) root is the only user account that will have a password, I am testing with two user accounts "dimas" and "sherry" which do not have a password set (passwords are blank, passwd -d user) The above essentially prevents everyone from logging into the system with passwords (a public/private key must be setup). Additionally users in the sudoers list have admin abilities. They can also su to different accounts. So basically "dimas" can sudo su sherry, however "dimas can NOT do su sherry. Similarly any user NOT in the sudoers list can NOT do su user or sudo su user. NOTE The above works but is considered poor security. Any script that is able to access code as the "dimas" or "sherry" users will be able to execute sudo to gain root access. A bug in ssh that allows remote users to log in despite the settings, a remote code execution in something like firefox, or any other flaw that allows unwanted code to run as the user will now be able to run as root. Sudo should always require a password or you may as well log in as root instead of some other user.

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  • Getting to grips with the stack in nasm

    - by MarkPearl
    Today I spent a good part of my day getting to grips with the stack and nasm. After looking at my notes on nasm I think this is one area for the course I am doing they could focus more on… So here are some snippets I have put together that have helped me understand a little bit about the stack… Simplest example of the stack You will probably see examples like the following in circulation… these demonstrate the simplest use of the stack… org 0x100 bits 16 jmp main main: push 42h push 43h push 44h mov ah,2h ;set to display characters pop dx    ;get the first value int 21h   ;and display it pop dx    ;get 2nd value int 21h   ;and display it pop dx    ;get 3rd value int 21h   ;and display it int 20h The output from above code would be… DCB Decoupling code using “call” and “ret” This is great, but it oversimplifies what I want to use the stack for… I do not know if this goes against the grain of assembly programmers or not, but I want to write loosely coupled assembly code – and I want to use the stack as a mechanism for passing values into my decoupled code. In nasm we have the call and return instructions, which provides a mechanism for decoupling code, for example the following could be done… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h mov dx,41h int 21h ret ;---------------------------------------- main: call displayChar int 20h   This would output the following to the console A So, it would seem that call and ret allow us to jump to segments of our code and then return back to the calling position – a form of segmenting the code into what we would called in higher order languages “functions” or “methods”. The only issue is, in higher order languages there is a way to pass parameters into the functions and return results. Because of the primitive nature of the call and ret instructions, this does not seem to be obvious. We could of course use the registers to pass values into the subroutine and set values coming out, but the problem with this is we… Have a limited number of registers Are threading our code with tight coupling (it would be hard to migrate methods outside of their intended use in a particular program to another one) With that in mind, I turn to the stack to provide a loosely coupled way of calling subroutines… First attempt with the Stack Initially I thought this would be simple… we could use code that looks as follows to achieve what I want… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov ah,2h pop dx int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h   However running this application does not give the desired result, I want an ‘A’ to be returned, and I am getting something totally different (you will to). Reading up on the call and ret instructions a discovery is made… they are pushing and popping things onto and off the stack as well… When the call instruction is executed, the current value of IP (the address of the instruction to follow) is pushed onto the stack, when ret is called, the last value on the stack is popped off into the IP register. In effect what the above code is doing is as follows with the stack… push 41h push current value of ip pop current value of ip to dx pop 41h to ip This is not what I want, I need to access the 41h that I pushed onto the stack, but the call value (which is necessary) is putting something in my way. So, what to do? Remember we have other registers we can use as well as a thing called indirect addressing… So, after some reading around, I came up with the following approach using indirect addressing… org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h call displayChar int 20h In essence, what I have done here is used a trick with the stack pointer… it goes as follows… Push 41 onto the stack Make the call to the function, which will push the IP register onto the stack and then jump to the displayChar label Move the value in the stack point to the bp register (sp currently points at IP register) Move the at the location of bp minus 2 bytes to dx (this is now the value 41h) display it, execute the ret instruction, which pops the ip value off the stack and goes back to the calling point This approach is still very raw, some further reading around shows that I should be pushing the value of bp onto the stack before replacing it with sp, but it is the starting thread to getting loosely coupled subroutines. Let’s see if you get what the following output would be? org 0x100 bits 16 jmp main ;---------------------------------------- displayChar: mov bp,sp mov ah,2h mov dx,[bp+4] int 21h mov dx,[bp+2] int 21h ret ;---------------------------------------- main: push 41h push 42h call displayChar int 20h The output is… AB Where to from here? If by any luck some assembly programmer comes along and see this code and notices that I have made some fundamental flaw in my logic… I would like to know, so please leave a comment… appreciate any feedback!

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  • Say What? Podcasting As Part of Your Content Marketing

    - by Mike Stiles
    What do you usually do in your car on the way to work?  Sing along to radio? Stream Pandora or iHeartRadio? Talk on the phone? Sit in total silence? Whatever it is you do, you could be using that time to make yourself an expert in any range of topics…using podcasts. We invite you to follow or subscribe to the daily Oracle Social Spotlight podcast, a quick roundup of the day’s top stories around social marketing and the social networks. After podcasts arrived in 2004, growth was steady but slow. The concept was strong: anyone with a passion for any subject could make a show for anyone who cared to listen. Enter the smartphone, iTunes, new podcasting platforms, and social, and podcasting became easier than ever and made more sense for both podcasters and listeners. Stats show 1 in 5 smartphone owners are podcast consumers and 29% of Americans have listened to a podcast. The potential audience is also larger than ever. “Baked in” podcast apps on over 200 million devices expose users to volumes of audio content with just a tap. 97 million Americans are driving to work every day by themselves. And 38% of Americans listen to audio on a digital device each week, a number that’s projected to double by 2015. Does that mean your brand should be podcasting? That’s part of a larger discussion about your overall content strategy, provided you have one. But if you do and podcasting is a component of it, here are some things to keep in mind: Don’t podcast just to do it. Podcast because you thought of a show customers and prospects will like that they can’t get anywhere else. Sound quality matters. Good microphones are not expensive. Bad sound is annoying, makes your brand feel cheap, and will turn today’s sophisticated ears off. The host matters. Many think they belong on the radio. Few actually do. Your brand’s host should be comfortable & likeable. A top advantage of a podcast is people can bond with a real person. It’s a trust opportunity, so don’t take it lightly. The content matters. “All killer, no filler” means don’t allow babbling just to fill enough time for an episode. Value the listeners’ time, because that time is hard to get. Put time, effort and creativity into it. Sure you’re a business, but you’re competing with content from professional media and showbiz producers. If you can include music, sound effects, and things that amuse the ears, do it. If you start, be consistent. The #1 flaw in podcasting is when listeners can’t count on another episode or don’t know when it’s coming. Don’t skip doing shows just because you can. Get committed. Get your cover art right. Podcasting is about audio, but people shop for podcasts by glancing through graphics. Yours has to be professional, cool, and informative to get listeners interested. Cross-promote your podcast on all your channels. The competition for listeners is fierce, so if you have existing audiences you can leverage to launch your show, use them. Optimize it for mobile. Assume that’s where most listening will take place. If you’re using one of the podcast platform apps, you should be in good shape. Frankly, the percentage of brands that are podcasting is quite low, and that’s okay. Once you move beyond blogging and start connecting with real voices, poor execution can do damage. But more (32%) marketers want to learn how to use podcasting, and more (23%) were increasing their podcasting throughout this year. Bottom line, you want to share your brand’s message and stories wherever your audience might be and in whatever way they prefer to take in content. Many prefer to do that while driving or working out, using the eyes and hands-free medium of audio. @mikestilesPhoto: stock.xchng

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  • What Can We Learn About Software Security by Going to the Gym

    - by Nick Harrison
    There was a recent rash of car break-ins at the gym. Not an epidemic by any stretch, probably 4 or 5, but still... My gym used to allow you to hang your keys from a peg board at the front desk. This way you could come to the gym dressed to work out, lock your valuables in your car, and not have anything to worry about. Ignorance is bliss. The problem was that anyone who wanted to could go pick up your car keys, click the unlock button and find your car. Once there, they could rummage through your stuff and then walk back in and finish their workout as if nothing had happened. The people doing this were a little smatter then the average thief and would swipe some but not all of your cash leaving everything else in place. Most thieves would steal the whole car and be busted more quickly. The victims were unaware that anything had happened for several days. Fortunately, once the victims realized what had happened, the gym was still able to pull security tapes and find out who was misbehaving. All of the bad guys were busted, and everyone can now breathe a sigh of relieve. It is once again safe to go to the gym. Except there was still a fundamental problem. Putting your keys on a peg board by the front door is just asking for bad things to happen. One person got busted exploiting this security flaw. Others can still be exploiting it. In fact, others may well have been exploiting it and simply never got caught. How long would it take you to realize that $10 was missing from your wallet, if everything else was there? How would you even know when it went missing? Would you go to the front desk and even bother to ask them to review security tapes if you were only missing a small amount. Once highlighted, it is easy to see how commonly such vulnerability may have been exploited. So the gym did the very reasonable precaution of removing the peg board. To me the most shocking part of this story is the resulting uproar from gym members losing the convenient key peg. How dare they remove the trusted peg board? How can I work out now, I have to carry my keys from machine to machine? How can I enjoy my workout with this added inconvenience? This all happened a couple of weeks ago, and some people are still complaining. In light of the recent high profile hacking, there are a couple of parallels that can be drawn. Many web sites are riddled with vulnerabilities are crazy and easily exploitable as leaving your car keys by the front door while you work out. No one ever considered thanking the people who were swiping these keys for pointing out the vulnerability. Without a hesitation, they had their gym memberships revoked and are awaiting prosecution. The gym did recognize the vulnerability for what it is, and closed up that attack vector. What can we learn from this? Monitoring and logging will not prevent a crime but they will allow us to identify that a crime took place and may help track down who did it. Once we find a security weakness, we need to eliminate it. We may never identify and eliminate all security weaknesses, but we cannot allow well known vulnerabilities to persist in our system. In our case, we are not likely to meet resistance from end users. We are more likely to meet resistance from stake holders, product owners, keeper of schedules and budgets. We may meet resistance from integration partners, co workers, and third party vendors. Regardless of the source, we will see resistance, but the weakness needs to be dealt with. There is no need to glorify a cracker for bringing to light a security weakness. Regardless of their claimed motives, they are not heroes. There is also no point in wasting time defending weaknesses once they are identified. Deal with the weakness and move on. In may be embarrassing to find security weaknesses in our systems, but it is even more embarrassing to continue ignoring them. Even if it is unpopular, we need to seek out security weaknesses and eliminate them when we find them. http://www.sans.org has put together the Common Weakness Enumeration http://cwe.mitre.org/ which lists out common weaknesses. The site navigation takes a little getting used to, but there is a treasure trove here. Here is the detail page for SQL Injection. It clearly states how this can be exploited, in case anyone doubts that the weakness should be taken seriously, and more importantly how to mitigate the risk.

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  • How to handle updated configuration when it's already been cloned for editing

    - by alexrussell
    Really sorry about the title that probably doesn't make much sense. Hopefully I can explain myself better here as it's something that's kinda bugged me for ages, and is now becoming a pressing concern as I write a bit of software with configuration. Most software comes with default configuration options stored in the app itself, and then there's a configuration file (let's say) that a user can edit. Once created/edited for the first time, subsequent updates to the application can not (easily) modify this configuration file for fear of clobbering the user's own changes to the default configuration. So my question is, if my application adds a new configurable parameter, what's the best way to aid discoverability of the setting and allow the user (developer) to override it as nicely as possible given the following constraints: I actually don't have a canonical default config in the application per se, it's more of a 'cascading filesystem'-like affair - the config template is stored in default/config.json and when the user wishes to edit the configuration, it's copied to user/config.json. If a user config is found it is used - there is no automatic overriding of a subset of keys, the whole new file is used and that's that. If there's no user config the default config is used. When a user wishes to edit the config they run a command to 'generate' it for them (which simply copies the config.json file from the default to the user directory). There is no UI for the configuration options as it's not appropriate to the userbase (think of my software as a library or something, the users are developers, the config is done in the user/config.json file). Due to my software being library-like there's no simple way to, on updating of the software, run some tasks automatically (so any ideas of look at the current config, compare to template config, add ing missing keys) aren't appropriate. The only solution I can think of right now is to say "there's a new config setting X" in release notes, but this doesn't seem ideal to me. If you want any more information let me know. The above specifics are not actually 100% true to my situation, but they represent the problem equally well with lower complexity. If you do want specifics, however, I can explain the exact setup. Further clarification of the type of configuration I mean: think of the Atom code editor. There appears to be a default 'template' config file somewhere, but as soon as a configuration option is edited ~/.atom/config.cson is generated and the setting goes in there. From now on is Atom is updated and gets a new configuration key, this file cannot be overwritten by Atom without a lot of effort to ensure that the addition/modification of the key does not clobber. In Atom's case, because there is a GUI for editing settings, they can get away with just adding the UI for the new setting into the UI to aid 'discoverability' of the new setting. I don't have that luxury. Clarification of my constraints and what I'm actually looking for: The software I'm writing is actually a package for a larger system. This larger system is what provides the configuration, and the way it works is kinda fixed - I just do a config('some.key') kinda call and it knows to look to see if the user has a config clone and if so use it, otherwise use the default config which is part of my package. Now, while I could make my application edit the user's configuration files (there is a convention about where they're stored), it's generally not done, so I'd like to live with the constraints of the system I'm using if possible. And it's not just about discoverability either, one large concern is that the addition of a configuration key won't actually work as soon as the user has their own copy of the original template. Adding the key to the template won't make a difference as that file is never read. As such, I think this is actually quite a big flaw in the design of the configuration cascading system and thus needs to be taken up with my upstream. So, thinking about it, based on my constraints, I don't think there's going to be a good solution save for either editing the user's configuration or using a new config file every time there are updates to the default configuration. Even the release notes idea from above isn't doable as, if the user does not follow the advice, suddenly I have a config key with no value (user-defined or default). So the new question is this: what is the general way to solve the problem of having a default configuration in template config files and allowing a user to make user-specific version of these in order to override the defaults? A per-key cascade (rather than per-file cascade) where the user only specifies their overrides? In this case, what happens if a configuration value is an array - do we replace or append to the default (or, more realistically, how does the user specify whether they wish to replace or append to)? It seems like configuration is kinda hard, so how is it solved in the wild?

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  • pyQt4: QWidget subclass not responding to new setStyleSheet() background colour

    - by Ronny
    I am having an issue with PyQt4. I want to create a new widget within a window, and I want this widget to have a custom color. When i create a subclass of the QWidget class, and instantiate it, I am not able to change its background color through the setStyleSheet() function. When I instantiate a new QWidget object, I have no problems in changing its background color. But i dont want an ordinary QWidget object.I want to create my own subclass of QWidget. When i create a subclass of a QPushButton, I am also able to change its background color using the setStyleSheet() function. There are no error messages or warnings in the console window, it just refuses to work properly without any indication as to why. So what i would like to know is why is it that i can change the background color of a widget if i simply create a QWidget object, or a subclass of QPushButton, but not when i create a subclass of QWidget. And how can i therefore change the background color of an object that is a subclass of QWidget? Is it maybe something specific to the version of python or PyQt that i am using? Is it a bug in the library? or some flaw in the way that i am writing my code? I am using python 2.6.4 and PyQt4 Below is an example of the code that leads me to trouble. There are three widgets within the window one below the other. The parent widget is set with background color of green. The top widget is set to red, the middle one, is the subclass of QWidget, which should be blue, but it appears invisible because it takes on the color of the parent window for some reason. and the bottom widget is a subclass of QPushButton and is white. import sys from PyQt4 import QtGui, QtCore ################################################################################ #--------------------------------------------------------- CUSTOM WIDGET CLASS 1 class CustomWidget(QtGui.QWidget): def __init__(self, parent): QtGui.QWidget.__init__(self, parent) # some custom properties and functions will follow ################################################################################ #--------------------------------------------------------- CUSTOM WIDGET CLASS 2 class CustomWidget2(QtGui.QPushButton): def __init__(self, parent): QtGui.QPushButton.__init__(self, parent) # some custom properties and functions will follow ################################################################################ #----------------------------------------------------------- PARENT WIDGET CLASS class Parent(QtGui.QWidget): def __init__(self, parent=None): #---------------------------------------------------------- SETUP WINDOW QtGui.QWidget.__init__(self, parent) self.resize(500, 340) self.setStyleSheet("QWidget {background-color: #00FF00}") #-------------------------------------------------- SETUP DEFAULT WIDGET wid1 = QtGui.QWidget(self) wid1.setGeometry(10, 10, 480, 100) wid1.setStyleSheet("QWidget {background-color: #FF0000 }") #------------------------------------------------- SETUP CUSTOM WIDGET 1 wid2 = CustomWidget(self) wid2.setGeometry(10, 120, 480, 100) wid2.setStyleSheet("QWidget {background-color: #0000FF }") for i in dir(wid2): print i #------------------------------------------------- SETUP CUSTOM WIDGET 2 wid3 = CustomWidget2(self) wid3.setGeometry(10, 230, 480, 100) wid3.setStyleSheet("QWidget {background-color: #FFFFFF }") ################################################################################ #-------------------------------------------------------------------------- MAIN app = QtGui.QApplication(sys.argv) win = Parent() win.show() app.exec_()

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  • How to avoid using duplicate savepoint names in nested transactions in nested stored procs?

    - by Gary McGill
    I have a pattern that I almost always follow, where if I need to wrap up an operation in a transaction, I do this: BEGIN TRANSACTION SAVE TRANSACTION TX -- Stuff IF @error <> 0 ROLLBACK TRANSACTION TX COMMIT TRANSACTION That's served me well enough in the past, but after years of using this pattern (and copy-pasting the above code), I've suddenly discovered a flaw which comes as a complete shock. Quite often, I'll have a stored procedure calling other stored procedures, all of which use this same pattern. What I've discovered (to my cost) is that because I'm using the same savepoint name everywhere, I can get into a situation where my outer transaction is partially committed - precisely the opposite of the atomicity that I'm trying to achieve. I've put together an example that exhibits the problem. This is a single batch (no nested stored procs), and so it looks a little odd in that you probably wouldn't use the same savepoint name twice in the same batch, but my real-world scenario would be too confusing to post. CREATE TABLE Test (test INTEGER NOT NULL) BEGIN TRAN SAVE TRAN TX BEGIN TRAN SAVE TRAN TX INSERT INTO Test(test) VALUES (1) COMMIT TRAN TX BEGIN TRAN SAVE TRAN TX INSERT INTO Test(test) VALUES (2) COMMIT TRAN TX DELETE FROM Test ROLLBACK TRAN TX COMMIT TRAN TX SELECT * FROM Test DROP TABLE Test When I execute this, it lists one record, with value "1". In other words, even though I rolled back my outer transaction, a record was added to the table. What's happening is that the ROLLBACK TRANSACTION TX at the outer level is rolling back as far as the last SAVE TRANSACTION TX at the inner level. Now that I write this all out, I can see the logic behind it: the server is looking back through the log file, treating it as a linear stream of transactions; it doesn't understand the nesting/hierarchy implied by either the nesting of the transactions (or, in my real-world scenario, by the calls to other stored procedures). So, clearly, I need to start using unique savepoint names instead of blindly using "TX" everywhere. But - and this is where I finally get to the point - is there a way to do this in a copy-pastable way so that I can still use the same code everywhere? Can I auto-generate the savepoint name on the fly somehow? Is there a convention or best-practice for doing this sort of thing? It's not exactly hard to come up with a unique name every time you start a transaction (could base it off the SP name, or somesuch), but I do worry that eventually there would be a conflict - and you wouldn't know about it because rather than causing an error it just silently destroys your data... :-(

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  • Retrieve names of running processes

    - by Dave DeLong
    Hi everyone, First off, I know that similar questions have been asked, but the answers provided haven't been very helpful so far (they all recommend one of the following options). I have a user application that needs to determine if a particular process is running. Here's what I know about the process: The name The user (root) It should already be running, since it's a LaunchDaemon, which means Its parent process should be launchd (pid 1) I've tried several ways to get this, but none have worked so far. Here's what I've tried: Running ps and parsing the output. This works, but it's slow (fork/exec is expensive), and I'd like this to be as fast as possible. Using the GetBSDProcessList function listed here. This also works, but the way in which they say to retrieve the process name (accessing kp_proc.p_comm from each kinfo_proc structure) is flawed. The resulting char* only contains the first 16 characters of the process name, which can be seen in the definition of the kp_proc structure: #define MAXCOMLEN 16 //defined in param.h struct extern_proc { //defined in proc.h ...snip... char p_comm[MAXCOMLEN+1]; ...snip... }; Using libProc.h to retrieve process information: pid_t pids[1024]; int numberOfProcesses = proc_listpids(PROC_ALL_PIDS, 0, NULL, 0); proc_listpids(PROC_ALL_PIDS, 0, pids, sizeof(pids)); for (int i = 0; i < numberOfProcesses; ++i) { if (pids[i] == 0) { continue; } char name[1024]; proc_name(pids[i], name, sizeof(name)); printf("Found process: %s\n", name); } This works, except it has the same flaw as GetBSDProcessList. Only the first portion of the process name is returned. Using the ProcessManager function in Carbon: ProcessSerialNumber psn; psn.lowLongOfPSN = kNoProcess; psn.highLongOfPSN = 0; while (GetNextProcess(&psn) == noErr) { CFStringRef procName = NULL; if (CopyProcessName(&psn, &procName) == noErr) { NSLog(@"Found process: %@", (NSString *)procName); } CFRelease(procName); } This does not work. It only returns process that are registered with the WindowServer (or something like that). In other words, it only returns apps with UIs, and only for the current user. I can't use -[NSWorkspace launchedApplications], since this must be 10.5-compatible. In addition, this only returns information about applications that appear in the Dock for the current user. I know that it's possible to retrieve the name of running processes (since ps can do it), but the question is "Can I do it without forking and exec'ing ps?". Any suggestions?

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  • Recommended textbook for machine-level programming?

    - by Norman Ramsey
    I'm looking at textbooks for an undergraduate course in machine-level programming. If the perfect book existed, this is what it would look like: Uses examples written in C or assembly language, or both. Covers machine-level operations such as two's-complement integer arithmetic, bitwise operations, and floating-point arithmetic. Explains how caches work and how they affect performance. Explains machine instructions or assembly instructions. Bonus if the example assembly language includes x86; triple bonus if it includes x86-64 (aka AMD64). Explains how C values and data structures are represented using hardware registers and memory. Explains how C control structures are translated into assembly language using conditional and unconditional branch instructions. Explains something about procedure calling conventions and how procedure calls are implemented at the machine level. Books I might be interested in would probably have the words "machine organization" or "computer architecture" in the title. Here are some books I'm considering but am not quite happy with: Computer Systems: A Programmer's Perspective by Randy Bryant and Dave O'Hallaron. This is quite a nice book, but it's a book for a broad, shallow course in systems programming, and it contains a great deal of material my students don't need. Also, it is just out in a second edition, which will make it expensive. Computer Organization and Design: The Hardware/Software Interface by Dave Patterson and John Hennessy. This is also a very nice book, but it contains way more information about how the hardware works than my students need. Also, the exercises look boring. Finally, it has a show-stopping bug: it is based very heavily on MIPS hardware and the use of a MIPS simulator. My students need to learn how to use DDD, and I can't see getting this to work on a simulator. Not to mention that I can't see them cross-compiling their code for the simulator, and so on and so forth. Another flaw is that the book mentions the x86 architecture only to sneer at it. I am entirely sympathetic to this point of view, but news flash! You guys lost! Write Great Code Vol I: Understanding the Machine by Randall Hyde. I haven't evaluated this book as thoroughly as the other two. It has a lot of what I need, but the translation from high-level language to assembler is deferred to Volume Two, which has mixed reviews. My students will be annoyed if I make them buy a two-volume series, even if the price of those two volumes is smaller than the price of other books. I would really welcome other suggestions of books that would help students in a class where they are to learn how C-language data structures and code are translated to machine-level data structures and code and where they learn how to think about performance, with an emphasis on the cache.

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  • Speeding up templates in GAE-Py by aggregating RPC calls

    - by Sudhir Jonathan
    Here's my problem: class City(Model): name = StringProperty() class Author(Model): name = StringProperty() city = ReferenceProperty(City) class Post(Model): author = ReferenceProperty(Author) content = StringProperty() The code isn't important... its this django template: {% for post in posts %} <div>{{post.content}}</div> <div>by {{post.author.name}} from {{post.author.city.name}}</div> {% endfor %} Now lets say I get the first 100 posts using Post.all().fetch(limit=100), and pass this list to the template - what happens? It makes 200 more datastore gets - 100 to get each author, 100 to get each author's city. This is perfectly understandable, actually, since the post only has a reference to the author, and the author only has a reference to the city. The __get__ accessor on the post.author and author.city objects transparently do a get and pull the data back (See this question). Some ways around this are Use Post.author.get_value_for_datastore(post) to collect the author keys (see the link above), and then do a batch get to get them all - the trouble here is that we need to re-construct a template data object... something which needs extra code and maintenance for each model and handler. Write an accessor, say cached_author, that checks memcache for the author first and returns that - the problem here is that post.cached_author is going to be called 100 times, which could probably mean 100 memcache calls. Hold a static key to object map (and refresh it maybe once in five minutes) if the data doesn't have to be very up to date. The cached_author accessor can then just refer to this map. All these ideas need extra code and maintenance, and they're not very transparent. What if we could do @prefetch def render_template(path, data) template.render(path, data) Turns out we can... hooks and Guido's instrumentation module both prove it. If the @prefetch method wraps a template render by capturing which keys are requested we can (atleast to one level of depth) capture which keys are being requested, return mock objects, and do a batch get on them. This could be repeated for all depth levels, till no new keys are being requested. The final render could intercept the gets and return the objects from a map. This would change a total of 200 gets into 3, transparently and without any extra code. Not to mention greatly cut down the need for memcache and help in situations where memcache can't be used. Trouble is I don't know how to do it (yet). Before I start trying, has anyone else done this? Or does anyone want to help? Or do you see a massive flaw in the plan?

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  • Help with strange memory behavior. Looking for leaks both in my brain and in my code.

    - by BastiBechtold
    I spent the last few days trying to find memory leaks in a program we are developing. First of all, I tried using some leak detectors. After fixing a few issues, they do not find any leaks any more. However, I am also monitoring my application using perfmon.exe. Performance Monitor reports that 'Private Bytes' and 'Working Set - Private' are steadily rising when the app is used. To me, this suggests that the program is using more and more memory the longer it runs. Internal resources seem to be stable however, so this sounds like leaking to me. The program is loading a DLL at runtime. I suspect that these leaks or whatever they are occur in that library and get purged when the library is unloaded, hence they won't get picked up by the leak detectors. I used both DevPartner BoundsChecker and Virtual Leak Detector to look for memory leaks. Both supposedly catch leaks in DLLs. Also, the memory consumption is increasing in steps and those steps roughly, but not exactly, coincide with certain GUI actions I perform in the application. If these were errors in our code, they should get triggered every single time the actions are performed and not just most of the time. Whenever I am confronted with so much strangeness, I begin to question my basic assumptions. So I turn to you, who know everything, for suggestions. Is there a flaw in my assumptions? Do you have an idea of how to go about troubleshooting a problem like this? Edit: I am currently using Microsoft Visual C++ (x86) on Windows 7 64. Edit2: I just used IBM Purify to hunt for leaks. First of all, it lists a full 30% of the program as leaked memory. This can not be true. I guess it is identifying the whole DLL as leaked or something like that. However, if I search for new leaks every few actions, it reports leaks that correspond with the size increase reported by Performance Monitor. This could be a lead to a leak. Sadly, I am only using the trial version of Purify, so it won't show me the actual location of those leaks. (These leaks only show up at runtime. When the program exits, there are no leaks whatsoever reported by any tool.)

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  • PHP GD Allowed memory size exhausted

    - by gurun8
    I'm trying to process a directory of JPEG images (roughly 600+, ranging from 50k to 500k) using PHP: GD to resize and save the images but I've hit a bit of a snag quite early in the process. After correctly processing just 3 images (30K, 18K and 231K) I get a Allowed memory size of 16777216 bytes exhausted PHP Fatal error. I'm cycling through the images and calling the code below: list($w, $h) = getimagesize($src); if ($w > $it->width) { $newwidth = $it->width; $newheight = round(($newwidth * $h) / $w); } elseif ($w > $it->height) { $newheight = $it->height; $newwidth = round(($newheight * $w) / $h); } else { $newwidth = $w; $newheight = $h; } // create resize image $img = imagecreatetruecolor($newwidth, $newheight); $org = imagecreatefromjpeg($src); // Resize imagecopyresized($img, $org, 0, 0, 0, 0, $newwidth, $newheight, $w, $h); imagedestroy($org); imagejpeg($img, $dest); // Free up memory imagedestroy($img); I've tried to free up memory with the imagedestroy function but it doesn't seem to have any affect. The script just keeps consistently choking at the imagecreatefromjpeg line of code. I checked the php.ini and the memory_limit = 16M setting seems like it's holding correctly. But I can't figure out why the memory is filling up. Shouldn't it be releasing the memory back to the garbage collector? I don't really want to increase the memory_limit setting. This seems like a bad workaround that could potentially lead to more issues in the future. FYI: I'm running my script from a command prompt. It shouldn't affect the functionality but might influence your response so I thought I should mention it. Can anyone see if I'm just missing something simple or if there's a design flaw here? You'd think that this would be a pretty straightforward task. Surely this has to be possible, right?

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  • HTTP Post requests using HttpClient take 2 seconds, why?

    - by pableu
    Update: You might better hold off this for a bit, I just noticed I could be my fault after all. Working on this all afternoon, and then I find a flaw ten minutes after posting here, ts. Hi, I'am currently coding an android app that submits stuff in the background using HTTP Post and AsyncTask. I use the org.apache.http.client Package for this. I based my code on this example. Basically, my code looks like this: public void postData() { // Create a new HttpClient and Post Header HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost("http://192.168.1.137:8880/form"); try { List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); nameValuePairs.add(new BasicNameValuePair("id", "12345")); nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!")); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); // Execute HTTP Post Request HttpResponse response = httpclient.execute(httppost); } catch (ClientProtocolException e) { Log.e(TAG,e.toString()); } catch (IOException e) { Log.e(TAG,e.toString()); } } The problem is that the httpclient.execute(..) line takes around 1.5 to 3 seconds, and I do not understand why. Just requesting a page with HTTP Get takes around 80 ms or so, so the problem doesn't seem to be the network latency itself. The problem doesn't seem to be on the server side either, I have also tried POSTing data to http://www.disney.com/ with similarly slow results. And Firebug shows 1 ms response time when POSTing data to my server locally. This happens on the Emulator and with my Nexus One (both with Android 2.2). If you want to look at the complete code, I've put it on GitHub. It's just a dummy program to do HTTP Post in the background using AsyncTask on the push of a button. It's my first Android app, and my first java code for a long time. And incidentially, also my first question on Stackoverflow ;-) Any ideas why httpclient.execute(httppost) takes so long?

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  • Unable to find assembly, C#

    - by PlasmaCube
    So, here's the deal. I've got two ASP.NET applications, both of which use SQLServer Session State management. They also both use the same server. I've got a custom session class in an external DLL, which fully implements serialization, and which both applications have referenced. Each application, in turn, has a class which inherits from the DLL class, and both applications use their own respective classes for their session state. Now, what I was trying to accomplish was that if you wanted to go to the other application, it could look in the session (they all use the same session key) and treat the existing object there as the base (the one from the DLL), extract whatever login info you need, then overwrite the session object with your own. Unfortunately, when the second application attempts to read the session, it seems that it looks for the DLL of the first application, and when it can't find it, it throws an exception. Is there a flaw in my logic? Here's an example: // Global.asax of the 1st app protected void Session_Start(object sender, EventArgs e) { Session.Add( "UserSessionKey", new FirstUserSession()); // FirstUserSession inherits from BaseUserSession } Now the second application: // Global.asax of 2nd app protected void Session_Start(object sender, EventArgs e) { if (Session["UserSessionKey"] != null) { BaseUserSession existing = (BaseUserSession)Session["UserSessionKey"]; SecondUserSession session = new SecondUserSession(); // This also inherits from BaseUserSession session.Authenticated = existing.Authenticated; session.Id = existing.Id; session.Role = existing.Role; Session.Add("UserSessionKey", session); } else { Session.Add("UserSessionKey", new SecondUserSession()); } } Here's the exception stack trace. In this case, "MyCBC" is the real name of the first app, and "ASPTesting" is the second app. [SerializationException: Unable to find assembly 'MyCBC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.] System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly() +1871092 System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name) +7545734 System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +120 System.Runtime.Serialization.Formatters.Binary.ObjectMap.Create(String name, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +52 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record) +190 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum) +61 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run() +253 System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +168 System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +203 System.Web.Util.AltSerialization.ReadValueFromStream(BinaryReader reader) +788 System.Web.SessionState.SessionStateItemCollection.ReadValueFromStreamWithAssert() +55 System.Web.SessionState.SessionStateItemCollection.DeserializeItem(String name, Boolean check) +281 System.Web.SessionState.SessionStateItemCollection.get_Item(String name) +19 System.Web.SessionState.HttpSessionStateContainer.get_Item(String name) +13 System.Web.SessionState.HttpSessionState.get_Item(String name) +13 ASPTesting._Default.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\sarsstu\My Documents\Projects\Testing\ASPTesting\ASPTesting\Default.aspx.cs:20 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 Thanks to everyone in advance.

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  • Publishing/subscribing multiple subsets of the same server collection

    - by matb33
    How does one go about publishing different subsets (or "views") of a single collection on the server as multiple collections on the client? Here is some pseudo-code to help illustrate my question: items collection on the server Assume that I have an items collection on the server with millions of records. Let's also assume that: 50 records have the enabled property set to true, and; 100 records have the processed property set to true. All others are set to false. items: { "_id": "uniqueid1", "title": "item #1", "enabled": false, "processed": false }, { "_id": "uniqueid2", "title": "item #2", "enabled": false, "processed": true }, ... { "_id": "uniqueid458734958", "title": "item #458734958", "enabled": true, "processed": true } Server code Let's publish two "views" of the same server collection. One will send down a cursor with 50 records, and the other will send down a cursor with 100 records. There are over 458 million records in this fictitious server-side database, and the client does not need to know about all of those (in fact, sending them all down would probably take several hours in this example): var Items = new Meteor.Collection("items"); Meteor.publish("enabled_items", function () { // Only 50 "Items" have enabled set to true return Items.find({enabled: true}); }); Meteor.publish("processed_items", function () { // Only 100 "Items" have processed set to true return Items.find({processed: true}); }); Client code In order to support the latency compensation technique, we are forced to declare a single collection Items on the client. It should become apparent where the flaw is: how does one differentiate between Items for enabled_items and Items for processed_items? var Items = new Meteor.Collection("items"); Meteor.subscribe("enabled_items", function () { // This will output 50, fine console.log(Items.find().count()); }); Meteor.subscribe("processed_items", function () { // This will also output 50, since we have no choice but to use // the same "Items" collection. console.log(Items.find().count()); }); My current solution involves monkey-patching _publishCursor to allow the subscription name to be used instead of the collection name. But that won't do any latency compensation. Every write has to round-trip to the server: // On the client: var EnabledItems = new Meteor.Collection("enabled_items"); var ProcessedItems = new Meteor.Collection("processed_items"); With the monkey-patch in place, this will work. But go into Offline mode and changes won't appear on the client right away -- we'll need to be connected to the server to see changes. What's the correct approach?

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  • Passing enums to functions in C++

    - by rocknroll
    Hi all, I have a header file with all the enums listed (#ifndef #define #endif construct has been used to avoid multiple inclusion of the file) that I use in multiple cpp files in my application.One of the enums in the files is enum StatusSubsystem {ENABLED,INCORRECT_FRAME,INVALID_DATA,DISABLED}; There are functions in the application delcared as ShowStatus(const StatusSubsystem&); Earlier in the application when I made calls to the above function like ShowStatus(INCORRECT_FRAME); my application used to compile perfectly. But after some code was added The compilation halts giving the following error: File.cpp:71: error: invalid conversion from `int' to `StatusSubsystem' File.cpp:71: error: initializing argument 1 of `void Class::ShowStatus(const StatusSubsystem&) I checked the code for any conflicting enums in the new code and it looked fine. My Question is what is wrong with the function call that compiler shows as erroneous? For your reference the function definition is: void Class::ShowStatus(const StatusSubsystem& eStatus) { QPalette palette; mStatus=eStatus;//store current Communication status of system if(eStatus==DISABLED) { //select red color for label, if it is to be shown disabled palette.setColor(QPalette::Window,QColor(Qt::red)); mLabel->setText("SYSTEM"); } else if(eStatus==ENABLED) { //select green color for label,if it is to be shown enabled palette.setColor(QPalette::Window,QColor(Qt::green)); mLabel->setText("SYSTEM"); } else if(eStatus==INCORRECT_FRAME) { //select yellow color for label,to show that it is sending incorrect frames palette.setColor(QPalette::Window,QColor(Qt::yellow)); mLabel->setText("SYSTEM(I)"); } //Set the color on the Label mLabel->setPalette(palette); } A strange side effect of this situation is it compiles when I cast all the calls to ShowStatus() as ShowStatus((StatusSubsystem)INCORRECT_FRAME); Though this removes any compilation error, but a strange thing happens. Though I make call to INCORRECT_FRAME above but in function definition it matches with ENABLED. How on earth is that possible? Its like while passing INCORRECT_FRAME by reference, it magically converts to ENABLED, which should be impossible. This is driving me nuts. Can you find any flaw in what I am doing? or is it something else? The application is made using C++,Qt-4.2.1 on RHEL4. Thanks.

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  • How to store array of NSManagedObjects in an NSManagedObject

    - by David Tay
    I am loading my app with a property list of data from a web site. This property list file contains an NSArray of NSDictionaries which itself contains an NSArray of NSDictionaries. Basically, I'm trying to load a tableView of restaurant menu categories each of which contains menu items. My property list file is fine. I am able to load the file and loop through the nodes structure creating NSEntityDescriptions and am able to save to Core Data. Everything works fine and expectedly except that in my menu category managed object, I have an NSArray of menu items for that category. Later on, when I fetch the categories, the pointers to the menu items in a category is lost and I get all the menu items. Am I suppose to be using predicates or does Core Data keep track of my object graph for me? Can anyone look at how I am loading Core Data and point out the flaw in my logic? I'm pretty good with either SQL and OOP by themselves, but am a little bewildered by ORM. I thought that I should just be able to use aggregation in my managed objects and that the framework would keep track of the pointers for me, but apparently not. NSError *error; NSURL *url = [NSURL URLWithString:@"http://foo.com"]; NSArray *categories = [[NSArray alloc] initWithContentsOfURL:url]; NSMutableArray *menuCategories = [[NSMutableArray alloc] init]; for (int i=0; i<[categories count]; i++){ MenuCategory *menuCategory = [NSEntityDescription insertNewObjectForEntityForName:@"MenuCategory" inManagedObjectContext:[self managedObjectContext]]; NSDictionary *category = [categories objectAtIndex:i]; menuCategory.name = [category objectForKey:@"name"]; NSArray *items = [category objectForKey:@"items"]; NSMutableArray *menuItems = [[NSMutableArray alloc] init]; for (int j=0; j<[items count]; j++){ MenuItem *menuItem = [NSEntityDescription insertNewObjectForEntityForName:@"MenuItem" inManagedObjectContext:[self managedObjectContext]]; NSDictionary *item = [items objectAtIndex:j]; menuItem.name = [item objectForKey:@"name"]; menuItem.price = [item objectForKey:@"price"]; menuItem.image = [item objectForKey:@"image"]; menuItem.details = [item objectForKey:@"details"]; [menuItems addObject:menuItem]; } [menuCategory setValue:menuItems forKey:@"menuItems"]; [menuCategories addObject:menuCategory]; [menuItems release]; } if (![[self managedObjectContext] save:&error]) { NSLog(@"An error occurred: %@", [error localizedDescription]); }

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  • Udp server sending only 0 bytes of data

    - by mawia
    Hi all, This is a simple Udp server.I am trying to transmit data to some clients,but unfortunetly it is unable to transmit data.Though send is running quite successfully but it is returning with a return value meaning it has send nothing.On the client they are receiving but again obviously,zero bytes. void* UdpServerStreamToClients(void *fileToServe) { int sockfd,n=0,k; struct sockaddr_in servaddr,cliaddr; socklen_t len; char dataToSend[1000]; sockfd=socket(AF_INET,SOCK_DGRAM,0); bzero(&servaddr,sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr=htonl(INADDR_ANY); servaddr.sin_port=htons(32000); bind(sockfd,(struct sockaddr *)&servaddr,sizeof(servaddr)); FILE *fp; if((fp=fopen((char*)fileToServe,"r"))==NULL) { printf("can not open file "); perror("fopen"); exit(1); } int dataRead=1; while(dataRead) { len = sizeof(cliaddr); if((dataRead=fread(dataToSend,1,500,fp))<0) { perror("fread"); exit(1); } //sleep(2); for(list<clientInfo>::iterator it=clients.begin();it!=clients.end();it++) { cliaddr.sin_family = AF_INET; inet_aton(inet_ntoa(it->addr.sin_addr),&cliaddr.sin_addr); cliaddr.sin_port = htons(it->udp_port); n=sendto(sockfd,dataToSend,sizeof(dataToSend),0,(struct sockaddr *)&cliaddr,len); cout<<"number of bytes send by udp: "<< n << endl; printf("SEND this message %d : %s to %s :%d \n",n,dataToSend,inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port)); } } } I am checking the value of sizeof(dataTosend) and it is pretty much as expected ie thousand ie the size of buffer. Are you people seeing some possible flaw in it. All of the help in this regard will be appreciated. Thanks!

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  • How do you handle authentication across domains?

    - by William Ratcliff
    I'm trying to save users of our services from having to have multiple accounts/passwords. I'm in a large organization and there's one group that handles part of user authentication for users who are from outside the facility (primarily for administrative functions). They store a secure cookie to establish a session and communicate only via HTTPS via the browser. Sessions expire either through: 1) explicit logout of the user 2) Inactivity 3) Browser closes My team is trying to write a web application to help users analyze data that they've taken (or are currently taking) while at our facility. We need to determine if a user is 1) authenticated 2) Some identifier for that user so we can store state for them (what analysis they are working on, etc.) So, the problem is how do you authenticate across domains (the authentication server for the other application lives in a border region between public and private--we will live in the public region). We have come up with some scenarios and I'd like advice about what is best practice, or if there is one we haven't considered. Let's start with the case where the user is authenticated with the authentication server. 1) The authentication server leaves a public cookie in the browser with their primary key for a user. If this is deemed sensitive, they encrypt it on their server and we have the key to decrypt it on our server. When the user visits our site, we check for this public cookie. We extract the user_id and use a public api for the authentication server to request if the user is logged in. If they are, they send us a response with: response={ userid :we can then map this to our own user ids. If necessary, we can request additional information such as email-address/display name once (to notify them if long running jobs are done, or to share results with other people, like with google_docs). account_is_active:Make sure that the account is still valid session_is_active: Is their session still active? If we query this for a valid user, this will have a side effect that we will reset the last_time_session_activated value and thus prolong their session with the authentication server last_time_session_activated: let us know how much time they have left ip_address_session_started_from:make sure the person at our site is coming from the same ip as they started the session at } Given this response, we either accept them as authenticated and move on with our app, or redirect them to the login page for the authentication server (question: if we give an encrypted portion of the response (signed by us) with the page to redirect them to, do we open any gaping security holes in the authentication server)? The flaw that we've found with this is that if the user visits evilsite.com and they look at the session cookie and send a query to the public api of the authentication server, they can keep the session alive and if our original user leaves the machine without logging out, then the next user will be able to access their session (this was possible before, but having the session alive eternally makes this worse). 2) The authentication server redirects all requests made to our domain to us and we send responses back through them to the user. Essentially, they act as a proxy. The advantage of this is that we can handshake with the authentication server, so it's safe to be trusted with the email address/name of the user and they don't have to reenter it So, if the user tries to go to: authentication_site/mysite_page1 they are redirected to mysite. Which would you choose, or is there a better way? The goal is to minimize the "Yet Another Password/Yet another username" problem... Thanks!!!!

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  • Dhcpd Daemon is trying to lease itself?

    - by tommieb75
    I have a Slackware Linux 13.0 box with two interfaces, eth0 and eth1. I have set this box up to be on the 192.168.1.0/24 network, with subnet mask of 255.255.255.0. I am trying to run a dhcpd server on this box to service two interfaces above, so I subnetted the 192.168.1.0/24 network into two subnets. For eth0 192.168.1.1, subnet mask 255.255.255.128, broadcast mask 192.168.1.127. For eth1 192.168.1.129, subnet mask 255.255.255.128, broadcast mask 192.168.1.255. Both the interfaces are assigned manually. eth0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 inet addr:192.168.1.1 Bcast:192.168.1.127 Mask:255.255.255.128 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:39 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:1404 (1.3 KiB) Interrupt:11 Base address:0x8000 Memory:faffc000-faffcfff eth1 Link encap:Ethernet HWaddr 00:00:00:00:00:00 inet addr:192.168.1.128 Bcast:192.168.1.255 Mask:255.255.255.128 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:10003 errors:0 dropped:0 overruns:0 frame:0 TX packets:13286 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1589229 (1.5 MiB) TX bytes:9900005 (9.4 MiB) Interrupt:11 Here is the dhcpd.conf set up authoritative; ddns-update-style interim; ignore client-updates; subnet 192.168.1.0 netmask 255.255.255.128 { range 192.168.1.2 192.168.1.126; default-lease-time 86400; max-lease-time 86400; option routers 192.168.1.1; option ip-forwarding off; option domain-name-servers 208.67.222.222, 208.67.220.220; option broadcast-address 192.168.1.127; option subnet-mask 255.255.255.128; } subnet 192.168.1.128 netmask 255.255.255.128 { range 192.168.1.129 192.168.1.254; default-lease-time 86400; max-lease-time 86400; option routers 192.168.1.1; option ip-forwarding off; option domain-name-servers 208.67.222.222, 208.67.220.220; option broadcast-address 192.168.1.255; option subnet-mask 255.255.255.128; } This is what is showing in the log Apr 10 18:09:58 inspiron8600 dhcpd: DHCPDISCOVER from 00:00:00:00:00:00 (inspiron8600) via eth1 Apr 10 18:09:58 inspiron8600 dhcpd: DHCPOFFER on 192.168.1.131 to 00:00:00:00:00:00 (inspiron8600) via eth1 Apr 10 18:10:01 inspiron8600 dhcpcd[3832]: eth1: adding IP address 169.254.153.6/16 This is happening spuriously, and the log gets filled up with nonsense..so my question is this: How do I stop this from happening? And why would it be trying to give itself a lease? I am sure I have missed something but cannot see it and would appreciate a pair of eyes from the community to spot the obvious flaw!

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