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  • DNS delegation on same server with DDNS and second slave server

    - by Austin
    I have two servers running BIND, the first is setup as the master of two zones and the second as a slave for those zones. The zones are example.com and ddns.example.com. I have DDNS running and thousands of device entries are dynamically created in ddns.example.com. I wanted to keep DDNS separate from the main example.com, so I created a separate zone that the DHCP servers update. Considering these zones are hosted on the same server, is it possible to have delegation working from example.com to ddns.example.com? For example if my workstation's search domain is example.com and pointed towards 10.1.10.1 for its DNS provider, I would like to be able to resolve hostname.ddns. As it is, I can resolve hostname.ddns.example.com, but would like to be able to resolve just hostname.ddns. Alternatively, if the workstation's search domain is ddns.example.com, what settings do I need to be able to change to be able to resolve web, ftp, etc, which are all hosts in the parent, example.com zone? Does the ddns.example.com zone need to forward to the example.com zone? Again, all the zones are setup on the same server with a second server setup as a slave. named.conf: zone "example.com" IN { type master; file "example.com"; allow-update { none; }; } zone "ddns.example.com" IN { type master; file "ddns.example.com"; allow-update { key dhcp-update; }; } example.com zone file: $ORIGIN . $TTL 86400 example.com IN SOA ns1.example.com. hostmaster.example.com. ( serial, refresh, retry, etc. ) NS ns1.example.com. NS ns2.example.com. $ORIGIN example.com. ns1 A 10.1.10.1 ns2 A 10.1.10.2 web A 10.1.15.30 ftp A 10.1.15.31 host3 A 10.1.15.32 $ORIGIN ddns.example.com NS ns1 NS ns2 ns1 A 10.1.10.1 ns2 A 10.1.10.2

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  • How to kill slave kernel securely?

    - by Alexey Popkov
    Hello, LinkClose[link] "does not necessarily terminate the program at the other end of the connection" as it is said in the Documentation. Is there a way to kill the process of the slave kernel securely? EDIT: In really I need a function in Mathematica that returns only when the process of the slave kernel has already killed and its memory has already released. Both LinkInterrupt[link, 1] and LinkClose[link] do not wait while the slave kernel exits. At this moment the only such function is seemed to be killProc[procID] function I had showed in one of answers at this page. But is there a built-in analog?

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  • Benchmarking MySQL Replication with Multi-Threaded Slaves

    - by Mat Keep
    0 0 1 1145 6530 Homework 54 15 7660 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} The objective of this benchmark is to measure the performance improvement achieved when enabling the Multi-Threaded Slave enhancement delivered as a part MySQL 5.6. As the results demonstrate, Multi-Threaded Slaves delivers 5x higher replication performance based on a configuration with 10 databases/schemas. For real-world deployments, higher replication performance directly translates to: · Improved consistency of reads from slaves (i.e. reduced risk of reading "stale" data) · Reduced risk of data loss should the master fail before replicating all events in its binary log (binlog) The multi-threaded slave splits processing between worker threads based on schema, allowing updates to be applied in parallel, rather than sequentially. This delivers benefits to those workloads that isolate application data using databases - e.g. multi-tenant systems deployed in cloud environments. Multi-Threaded Slaves are just one of many enhancements to replication previewed as part of the MySQL 5.6 Development Release, which include: · Global Transaction Identifiers coupled with MySQL utilities for automatic failover / switchover and slave promotion · Crash Safe Slaves and Binlog · Optimized Row Based Replication · Replication Event Checksums · Time Delayed Replication These and many more are discussed in the “MySQL 5.6 Replication: Enabling the Next Generation of Web & Cloud Services” Developer Zone article  Back to the benchmark - details are as follows. Environment The test environment consisted of two Linux servers: · one running the replication master · one running the replication slave. Only the slave was involved in the actual measurements, and was based on the following configuration: - Hardware: Oracle Sun Fire X4170 M2 Server - CPU: 2 sockets, 6 cores with hyper-threading, 2930 MHz. - OS: 64-bit Oracle Enterprise Linux 6.1 - Memory: 48 GB Test Procedure Initial Setup: Two MySQL servers were started on two different hosts, configured as replication master and slave. 10 sysbench schemas were created, each with a single table: CREATE TABLE `sbtest` (    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,    `k` int(10) unsigned NOT NULL DEFAULT '0',    `c` char(120) NOT NULL DEFAULT '',    `pad` char(60) NOT NULL DEFAULT '',    PRIMARY KEY (`id`),    KEY `k` (`k`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 10,000 rows were inserted in each of the 10 tables, for a total of 100,000 rows. When the inserts had replicated to the slave, the slave threads were stopped. The slave data directory was copied to a backup location and the slave threads position in the master binlog noted. 10 sysbench clients, each configured with 10 threads, were spawned at the same time to generate a random schema load against each of the 10 schemas on the master. Each sysbench client executed 10,000 "update key" statements: UPDATE sbtest set k=k+1 WHERE id = <random row> In total, this generated 100,000 update statements to later replicate during the test itself. Test Methodology: The number of slave workers to test with was configured using: SET GLOBAL slave_parallel_workers=<workers> Then the slave IO thread was started and the test waited for all the update queries to be copied over to the relay log on the slave. The benchmark clock was started and then the slave SQL thread was started. The test waited for the slave SQL thread to finish executing the 100k update queries, doing "select master_pos_wait()". When master_pos_wait() returned, the benchmark clock was stopped and the duration calculated. The calculated duration from the benchmark clock should be close to the time it took for the SQL thread to execute the 100,000 update queries. The 100k queries divided by this duration gave the benchmark metric, reported as Queries Per Second (QPS). Test Reset: The test-reset cycle was implemented as follows: · the slave was stopped · the slave data directory replaced with the previous backup · the slave restarted with the slave threads replication pointer repositioned to the point before the update queries in the binlog. The test could then be repeated with identical set of queries but a different number of slave worker threads, enabling a fair comparison. The Test-Reset cycle was repeated 3 times for 0-24 number of workers and the QPS metric calculated and averaged for each worker count. MySQL Configuration The relevant configuration settings used for MySQL are as follows: binlog-format=STATEMENT relay-log-info-repository=TABLE master-info-repository=TABLE As described in the test procedure, the slave_parallel_workers setting was modified as part of the test logic. The consequence of changing this setting is: 0 worker threads:    - current (i.e. single threaded) sequential mode    - 1 x IO thread and 1 x SQL thread    - SQL thread both reads and executes the events 1 worker thread:    - sequential mode    - 1 x IO thread, 1 x Coordinator SQL thread and 1 x Worker thread    - coordinator reads the event and hands it to the worker who executes 2+ worker threads:    - parallel execution    - 1 x IO thread, 1 x Coordinator SQL thread and 2+ Worker threads    - coordinator reads events and hands them to the workers who execute them Results Figure 1 below shows that Multi-Threaded Slaves deliver ~5x higher replication performance when configured with 10 worker threads, with the load evenly distributed across our 10 x schemas. This result is compared to the current replication implementation which is based on a single SQL thread only (i.e. zero worker threads). Figure 1: 5x Higher Performance with Multi-Threaded Slaves The following figure shows more detailed results, with QPS sampled and reported as the worker threads are incremented. The raw numbers behind this graph are reported in the Appendix section of this post. Figure 2: Detailed Results As the results above show, the configuration does not scale noticably from 5 to 9 worker threads. When configured with 10 worker threads however, scalability increases significantly. The conclusion therefore is that it is desirable to configure the same number of worker threads as schemas. Other conclusions from the results: · Running with 1 worker compared to zero workers just introduces overhead without the benefit of parallel execution. · As expected, having more workers than schemas adds no visible benefit. Aside from what is shown in the results above, testing also demonstrated that the following settings had a very positive effect on slave performance: relay-log-info-repository=TABLE master-info-repository=TABLE For 5+ workers, it was up to 2.3 times as fast to run with TABLE compared to FILE. Conclusion As the results demonstrate, Multi-Threaded Slaves deliver significant performance increases to MySQL replication when handling multiple schemas. This, and the other replication enhancements introduced in MySQL 5.6 are fully available for you to download and evaluate now from the MySQL Developer site (select Development Release tab). You can learn more about MySQL 5.6 from the documentation  Please don’t hesitate to comment on this or other replication blogs with feedback and questions. Appendix – Detailed Results

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  • What is the best resizable circular byte buffer available in Java?

    - by Wouter Lievens
    I need a byte buffer class in Java for single-threaded use. I should be able to insert data at the back of the buffer and read data at the front, with an amortized cost of O(1). The buffer should resize when it's full, rather than throw an exception or something. I could write one myself, but I'd be very surprised if this didn't exist yet in a standard Java package, and if it doesn't, I'd expect it to exist in some well-tested public library. What would you recommend?

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  • "Slave" user accounts in GNU/Linux

    - by Vi
    How to make one user account to be like root for some other user account, e.g. to be able to read, write, chmod all it's files, chown from this account to master and back, kill/ptrace all it's processes and to all thinks root can, but limited only to that particular slave account? Now I'm simulating this by allowing "master" user to "sudo -u slaveuser" and setting setfacl -dRm u:masteruser:rwx ~slaveuser. It is useful as I run most desktop programs in separate user accounts, but need to move files between them sometimes. If it requires some simple kernel patch it is OK.

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  • Magento hosting on a budget

    - by spa
    I have to do a setup for Magento. My constraint is primarily ease of setup and fault tolerance/fail over. Furthermore costs are an issue. I have three identical physical servers to get the job done. Each server node has an i7 quad core, 16GB RAM, and 2x3TB HD in a software RAID 1 configuration. Each node runs Ubuntu 12.04. right now. I have an additional IP address which can be routed to any of these nodes. The Magento shop has max. 1000 products, 50% of it are bundle products. I would estimate that max. 100 users are active at once. This leads me to the conclusion, that performance is not top priority here. My first setup idea One node (lb) runs nginx as a load balancer. The additional IP is used with domain name and routed to this node by default. Nginx distributes the load equally to the other two nodes (shop1, shop2). Shop1 and shop2 are configured equally: each server runs Apache2 and MySQL. The Mysqls are configured with master/slave replication. My failover strategy: Lb fails = Route IP to shop1 (MySQL master), continue. Shop1 fails = Lb will handle that automatically, promote MySQL slave on shop2 to master, reconfigure Magento to use shop2 for writes, continue. Shop2 fails = Lb will handle that automatically, continue. Is this a sane strategy? Has anyone done a similar setup with Magento? My second setup idea Another way to do it would be to use drbd for storing the MySQL data files on shop1 and shop2. I understand that in this scenario only one node/MySQL instance can be active and the other is used as hot standby. So in case shop1 fails, I would start up MySQL on shop2, route the IP to shop2, and continue. I like that as the MySQL setup is easier and the nodes can be configured 99% identical. So in this case the load balancer becomes useless and I have a spare server. My third setup idea The third way might be master-master replication of MySQL databases. However, in my optinion this might be tricky, as Magento isn't build for this scenario (e.g. conflicting ids for new rows). I would not do that until I have heard of a working example. Could you give me an advice which route to follow? There seems not one "good" way to do it. E.g. I read blog posts which describe a MySQL master/slave setup for Magento, but elsewhere I read, that data might get duplicated when the slave lags behind the master (e.g. when an order is placed, a customer might get created twice). I'm kind of lost here.

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  • Read varbinary data in java

    - by masoud farahani
    I made a Java application which reads some files from SQL server. Those files are saved to a varbinary(MAX) field in SQL Server by a third party web service. My problem is that when I want to read those files with my Java application, those binary data show different content in the Java application. In fact, I read data byte by byte and I figured out that some bytes did not show the real values which were saved in the database. I found out what the problem is, but I couldn’t find a solution yet. I found out that in the web service every varbinary data is saved to database as byte data (in .Net each byte takes 0 to 255). But, when I want to read the binary data in Java, it takes different values and cause an exception with some values, because in Java a byte value takes -127 to 127. In my Java application I want to write those data to a file by OutputStream.write(byte[]) method. How can I solve this problem? I think that I have to find a way to convert c# byte[] to a Java byte[] (or binary data), but how can I do that?

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  • temporary tables within stored procedures on slave servers with readonly set

    - by lau
    Hi, We have set up a replication scheme master/slave and we've had problems lately because some users wrote directly on the slave instead of the master, making the whole setup inconsistent. To prevent these problems from happening again, we've decided to remove the insert, delete, update, etc... rights from the users accessing the slave. Problems is that some stored procedure (for reading) require temporary tables. I read that changing the global variable read_only to true would do what I want and allow the stored procedures to work correctly ( http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_read_only ) but I keep getting the error : The MySQL server is running with the --read-only option so it cannot execute this statement (1290) The stored procedure that I used (for testing purpose) is this one : DELIMITER $$ DROP PROCEDURE IF EXISTS test_readonly $$ CREATE DEFINER=dbuser@% PROCEDURE test_readonly() BEGIN CREATE TEMPORARY TABLE IF NOT EXISTS temp ( BT_INDEX int(11), BT_DESC VARCHAR(10) ); INSERT INTO temp (BT_INDEX, BT_DESC) VALUES (222,'walou'), (111,'bidouille'); DROP TABLE temp; END $$ DELIMITER ; The create temporary table and the drop table work fine with the readonly flag - if I comment the INSERT line, it runs fine- but whenever I want to insert or delete from that temporary table, I get the error message. I use Mysql 5.1.29-rc. My default storage engine is InnoDB. Thanks in advance, this problem is really driving me crazy.

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  • How Byte loading/storing is implemented By the CPU?

    - by AlexDan
    I know that in 32bit machine, cpu read from memory 32bits at a time. since the registers in this case is 32bit in size too, I can understand how this works. What I don't understand is how the cpu implement load instructions of 1 byte. does it load the whole word where the single byte is located to the register, then perform some kind of "byte shifting", or does the cpu can load a single byte, in this case when does the byte masking happen, is it until the byte got loaded in the register, or it happen when byte is send through the data bus ? P.S. The cpu Im using is MIPS, the instructions Im talking about are: lb or lbu

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  • emacs hexl-mode insert or delete a byte

    - by Oleg Pavliv
    How can I insert or delete a byte in hexl-mode? Suppose I have a 3-byte file "123" which is displayed as "3132 33" in hexl-mode. How can I add a byte to get "1234"? How can I remove a byte to get "12"? Using C-M-x and similar shortcuts I can replace a byte, but I want to insert and delete.

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  • How to calculate Least Signficant Byte in Ruby

    - by Seth Archer
    I'm sending a byte array to a piece of hardware. The first 7 bytes contain data and the 8th byte is a checksum. The 8th byte is the Least Significant Byte of the sum of the first 7 bytes. Examples that include the correct checksum. The last byte of each of these is the checksum 200-30-7-5-1-2-0-245 42-0-0-1-176-0-148-39 42-0-0-3-177-0-201-118 How do I calculate the checksum? Thanks, Seth

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  • Representing a number in a byte array (java programming)

    - by Mark Roberts
    I'm trying to represent the port number 9876 (or 0x2694 in hex) in a two byte array: class foo { public static void main (String args[]) { byte[] sendData = new byte[1]; sendData[0] = 0x26; sendData[1] = 0x94; } } But I get a warning about possible loss of precision: foo.java:5: possible loss of precision found : int required: byte sendData[1] = 0x94; ^ 1 error How can I represent the number 9876 in a two byte array without losing precision?

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  • Error "Input length must be multiple of 8 when decrypting with padded cipher"

    - by Ross Peoples
    I am trying to move a project from C# to Java for a learning exercise. I am still very new to Java, but I have a TripleDES class in C# that encrypts strings and returns a string value of the encrypted byte array. Here is my C# code: using System; using System.IO; using System.Collections.Generic; using System.Security.Cryptography; using System.Text; namespace tDocc.Classes { /// <summary> /// Triple DES encryption class /// </summary> public static class TripleDES { private static byte[] key = { 110, 32, 73, 24, 125, 66, 75, 18, 79, 150, 211, 122, 213, 14, 156, 136, 171, 218, 119, 240, 81, 142, 23, 4 }; private static byte[] iv = { 25, 117, 68, 23, 99, 78, 231, 219 }; /// <summary> /// Encrypt a string to an encrypted byte array /// </summary> /// <param name="plainText">Text to encrypt</param> /// <returns>Encrypted byte array</returns> public static byte[] Encrypt(string plainText) { UTF8Encoding utf8encoder = new UTF8Encoding(); byte[] inputInBytes = utf8encoder.GetBytes(plainText); TripleDESCryptoServiceProvider tdesProvider = new TripleDESCryptoServiceProvider(); ICryptoTransform cryptoTransform = tdesProvider.CreateEncryptor(key, iv); MemoryStream encryptedStream = new MemoryStream(); CryptoStream cryptStream = new CryptoStream(encryptedStream, cryptoTransform, CryptoStreamMode.Write); cryptStream.Write(inputInBytes, 0, inputInBytes.Length); cryptStream.FlushFinalBlock(); encryptedStream.Position = 0; byte[] result = new byte[encryptedStream.Length]; encryptedStream.Read(result, 0, (int)encryptedStream.Length); cryptStream.Close(); return result; } /// <summary> /// Decrypt a byte array to a string /// </summary> /// <param name="inputInBytes">Encrypted byte array</param> /// <returns>Decrypted string</returns> public static string Decrypt(byte[] inputInBytes) { UTF8Encoding utf8encoder = new UTF8Encoding(); TripleDESCryptoServiceProvider tdesProvider = new TripleDESCryptoServiceProvider(); ICryptoTransform cryptoTransform = tdesProvider.CreateDecryptor(key, iv); MemoryStream decryptedStream = new MemoryStream(); CryptoStream cryptStream = new CryptoStream(decryptedStream, cryptoTransform, CryptoStreamMode.Write); cryptStream.Write(inputInBytes, 0, inputInBytes.Length); cryptStream.FlushFinalBlock(); decryptedStream.Position = 0; byte[] result = new byte[decryptedStream.Length]; decryptedStream.Read(result, 0, (int)decryptedStream.Length); cryptStream.Close(); UTF8Encoding myutf = new UTF8Encoding(); return myutf.GetString(result); } /// <summary> /// Decrypt an encrypted string /// </summary> /// <param name="text">Encrypted text</param> /// <returns>Decrypted string</returns> public static string DecryptText(string text) { if (text == "") { return text; } return Decrypt(Convert.FromBase64String(text)); } /// <summary> /// Encrypt a string /// </summary> /// <param name="text">Unencrypted text</param> /// <returns>Encrypted string</returns> public static string EncryptText(string text) { if (text == "") { return text; } return Convert.ToBase64String(Encrypt(text)); } } /// <summary> /// Random number generator /// </summary> public static class RandomGenerator { /// <summary> /// Generate random number /// </summary> /// <param name="length">Number of randomizations</param> /// <returns>Random number</returns> public static int GenerateNumber(int length) { byte[] randomSeq = new byte[length]; new RNGCryptoServiceProvider().GetBytes(randomSeq); int code = Environment.TickCount; foreach (byte b in randomSeq) { code += (int)b; } return code; } } /// <summary> /// Hash generator class /// </summary> public static class Hasher { /// <summary> /// Hash type /// </summary> public enum eHashType { /// <summary> /// MD5 hash. Quick but collisions are more likely. This should not be used for anything important /// </summary> MD5 = 0, /// <summary> /// SHA1 hash. Quick and secure. This is a popular method for hashing passwords /// </summary> SHA1 = 1, /// <summary> /// SHA256 hash. Slower than SHA1, but more secure. Used for encryption keys /// </summary> SHA256 = 2, /// <summary> /// SHA348 hash. Even slower than SHA256, but offers more security /// </summary> SHA348 = 3, /// <summary> /// SHA512 hash. Slowest but most secure. Probably overkill for most applications /// </summary> SHA512 = 4, /// <summary> /// Derrived from MD5, but only returns 12 digits /// </summary> Digit12 = 5 } /// <summary> /// Hashes text using a specific hashing method /// </summary> /// <param name="text">Input text</param> /// <param name="hash">Hash method</param> /// <returns>Hashed text</returns> public static string GetHash(string text, eHashType hash) { if (text == "") { return text; } if (hash == eHashType.MD5) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA1) { SHA1Managed hasher = new SHA1Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA256) { SHA256Managed hasher = new SHA256Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA348) { SHA384Managed hasher = new SHA384Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA512) { SHA512Managed hasher = new SHA512Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.Digit12) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); string newHash = ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); return newHash.Substring(0, 12); } return ""; } /// <summary> /// Generates a hash based on a file's contents. Used for detecting changes to a file and testing for duplicate files /// </summary> /// <param name="info">FileInfo object for the file to be hashed</param> /// <param name="hash">Hash method</param> /// <returns>Hash string representing the contents of the file</returns> public static string GetHash(FileInfo info, eHashType hash) { FileStream hashStream = new FileStream(info.FullName, FileMode.Open, FileAccess.Read); string hashString = ""; if (hash == eHashType.MD5) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA1) { SHA1Managed hasher = new SHA1Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA256) { SHA256Managed hasher = new SHA256Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA348) { SHA384Managed hasher = new SHA384Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA512) { SHA512Managed hasher = new SHA512Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } hashStream.Close(); hashStream.Dispose(); hashStream = null; return hashString; } /// <summary> /// Converts a byte array to a hex string /// </summary> /// <param name="data">Byte array</param> /// <returns>Hex string</returns> public static string ByteToHex(byte[] data) { StringBuilder builder = new StringBuilder(); foreach (byte hashByte in data) { builder.Append(string.Format("{0:X1}", hashByte)); } return builder.ToString(); } /// <summary> /// Converts a hex string to a byte array /// </summary> /// <param name="hexString">Hex string</param> /// <returns>Byte array</returns> public static byte[] HexToByte(string hexString) { byte[] returnBytes = new byte[hexString.Length / 2]; for (int i = 0; i <= returnBytes.Length - 1; i++) { returnBytes[i] = byte.Parse(hexString.Substring(i * 2, 2), System.Globalization.NumberStyles.HexNumber); } return returnBytes; } } } And her is what I've got for Java code so far, but I'm getting the error "Input length must be multiple of 8 when decrypting with padded cipher" when I run the test on this: import java.security.InvalidAlgorithmParameterException; import java.security.InvalidKeyException; import javax.crypto.Cipher; import javax.crypto.NoSuchPaddingException; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import com.tdocc.utils.Base64; public class TripleDES { private static byte[] keyBytes = { 110, 32, 73, 24, 125, 66, 75, 18, 79, (byte)150, (byte)211, 122, (byte)213, 14, (byte)156, (byte)136, (byte)171, (byte)218, 119, (byte)240, 81, (byte)142, 23, 4 }; private static byte[] ivBytes = { 25, 117, 68, 23, 99, 78, (byte)231, (byte)219 }; public static String encryptText(String plainText) { try { if (plainText.isEmpty()) return plainText; return Base64.decode(TripleDES.encrypt(plainText)).toString(); } catch (Exception e) { e.printStackTrace(); } return null; } public static byte[] encrypt(String plainText) throws InvalidKeyException, InvalidAlgorithmParameterException, NoSuchPaddingException { try { final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(ivBytes); final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, key, iv); final byte[] plainTextBytes = plainText.getBytes("utf-8"); final byte[] cipherText = cipher.doFinal(plainTextBytes); return cipherText; } catch (Exception e) { e.printStackTrace(); } return null; } public static String decryptText(String message) { try { if (message.isEmpty()) return message; else return TripleDES.decrypt(message.getBytes()); } catch (Exception e) { e.printStackTrace(); } return null; } public static String decrypt(byte[] message) { try { final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(ivBytes); final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, key, iv); final byte[] plainText = cipher.doFinal(message); return plainText.toString(); } catch (Exception e) { e.printStackTrace(); } return null; } }

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  • JAVA image transfer problem

    - by user579098
    Hi, I have a school assignment, to send a jpg image,split it into groups of 100 bytes, corrupt it, use a CRC check to locate the errors and re-transmit until it eventually is built back into its original form. It's practically ready, however when I check out the new images, they appear with errors.. I would really appreciate if someone could look at my code below and maybe locate this logical mistake as I can't understand what the problem is because everything looks ok :S For the file with all the data needed including photos and error patterns one could download it from this link:http://rapidshare.com/#!download|932tl2|443122762|Data.zip|739 Thanks in advance, Stefan p.s dont forget to change the paths in the code for the image and error files package networks; import java.io.*; // for file reader import java.util.zip.CRC32; // CRC32 IEEE (Ethernet) public class Main { /** * Reads a whole file into an array of bytes. * @param file The file in question. * @return Array of bytes containing file data. * @throws IOException Message contains why it failed. */ public static byte[] readFileArray(File file) throws IOException { InputStream is = new FileInputStream(file); byte[] data=new byte[(int)file.length()]; is.read(data); is.close(); return data; } /** * Writes (or overwrites if exists) a file with data from an array of bytes. * @param file The file in question. * @param data Array of bytes containing the new file data. * @throws IOException Message contains why it failed. */ public static void writeFileArray(File file, byte[] data) throws IOException { OutputStream os = new FileOutputStream(file,false); os.write(data); os.close(); } /** * Converts a long value to an array of bytes. * @param data The target variable. * @return Byte array conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static byte[] toByta(long data) { return new byte[] { (byte)((data >> 56) & 0xff), (byte)((data >> 48) & 0xff), (byte)((data >> 40) & 0xff), (byte)((data >> 32) & 0xff), (byte)((data >> 24) & 0xff), (byte)((data >> 16) & 0xff), (byte)((data >> 8) & 0xff), (byte)((data >> 0) & 0xff), }; } /** * Converts a an array of bytes to long value. * @param data The target variable. * @return Long value conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static long toLong(byte[] data) { if (data == null || data.length != 8) return 0x0; return (long)( // (Below) convert to longs before shift because digits // are lost with ints beyond the 32-bit limit (long)(0xff & data[0]) << 56 | (long)(0xff & data[1]) << 48 | (long)(0xff & data[2]) << 40 | (long)(0xff & data[3]) << 32 | (long)(0xff & data[4]) << 24 | (long)(0xff & data[5]) << 16 | (long)(0xff & data[6]) << 8 | (long)(0xff & data[7]) << 0 ); } public static byte[] nextNoise(){ byte[] result=new byte[100]; // copy a frame's worth of data (or remaining data if it is less than frame length) int read=Math.min(err_data.length-err_pstn, 100); System.arraycopy(err_data, err_pstn, result, 0, read); // if read data is less than frame length, reset position and add remaining data if(read<100){ err_pstn=100-read; System.arraycopy(err_data, 0, result, read, err_pstn); }else // otherwise, increase position err_pstn+=100; // return noise segment return result; } /** * Given some original data, it is purposefully corrupted according to a * second data array (which is read from a file). In pseudocode: * corrupt = original xor corruptor * @param data The original data. * @return The new (corrupted) data. */ public static byte[] corruptData(byte[] data){ // get the next noise sequence byte[] noise = nextNoise(); // finally, xor data with noise and return result for(int i=0; i<100; i++)data[i]^=noise[i]; return data; } /** * Given an array of data, a packet is created. In pseudocode: * frame = corrupt(data) + crc(data) * @param data The original frame data. * @return The resulting frame data. */ public static byte[] buildFrame(byte[] data){ // pack = [data]+crc32([data]) byte[] hash = new byte[8]; // calculate crc32 of data and copy it to byte array CRC32 crc = new CRC32(); crc.update(data); hash=toByta(crc.getValue()); // create a byte array holding the final packet byte[] pack = new byte[data.length+hash.length]; // create the corrupted data byte[] crpt = new byte[data.length]; crpt = corruptData(data); // copy corrupted data into pack System.arraycopy(crpt, 0, pack, 0, crpt.length); // copy hash into pack System.arraycopy(hash, 0, pack, data.length, hash.length); // return pack return pack; } /** * Verifies frame contents. * @param frame The frame data (data+crc32). * @return True if frame is valid, false otherwise. */ public static boolean verifyFrame(byte[] frame){ // allocate hash and data variables byte[] hash=new byte[8]; byte[] data=new byte[frame.length-hash.length]; // read frame into hash and data variables System.arraycopy(frame, frame.length-hash.length, hash, 0, hash.length); System.arraycopy(frame, 0, data, 0, frame.length-hash.length); // get crc32 of data CRC32 crc = new CRC32(); crc.update(data); // compare crc32 of data with crc32 of frame return crc.getValue()==toLong(hash); } /** * Transfers a file through a channel in frames and reconstructs it into a new file. * @param jpg_file File name of target file to transfer. * @param err_file The channel noise file used to simulate corruption. * @param out_file The name of the newly-created file. * @throws IOException */ public static void transferFile(String jpg_file, String err_file, String out_file) throws IOException { // read file data into global variables jpg_data = readFileArray(new File(jpg_file)); err_data = readFileArray(new File(err_file)); err_pstn = 0; // variable that will hold the final (transfered) data byte[] out_data = new byte[jpg_data.length]; // holds the current frame data byte[] frame_orig = new byte[100]; byte[] frame_sent = new byte[100]; // send file in chunks (frames) of 100 bytes for(int i=0; i<Math.ceil(jpg_data.length/100); i++){ // copy jpg data into frame and init first-time switch System.arraycopy(jpg_data, i*100, frame_orig, 0, 100); boolean not_first=false; System.out.print("Packet #"+i+": "); // repeat getting same frame until frame crc matches with frame content do { if(not_first)System.out.print("F"); frame_sent=buildFrame(frame_orig); not_first=true; }while(!verifyFrame(frame_sent)); // usually, you'd constrain this by time to prevent infinite loops (in // case the channel is so wacked up it doesn't get a single packet right) // copy frame to image file System.out.println("S"); System.arraycopy(frame_sent, 0, out_data, i*100, 100); } System.out.println("\nDone."); writeFileArray(new File(out_file),out_data); } // global variables for file data and pointer public static byte[] jpg_data; public static byte[] err_data; public static int err_pstn=0; public static void main(String[] args) throws IOException { // list of jpg files String[] jpg_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo1.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo2.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo3.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo4.jpg" }; // list of error patterns String[] err_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 1.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 2.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 3.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 4.DAT" }; // loop through all jpg/channel combinations and run tests for(int x=0; x<jpg_file.length; x++){ for(int y=0; y<err_file.length; y++){ System.out.println("Transfering photo"+(x+1)+".jpg using Pattern "+(y+1)+"..."); transferFile(jpg_file[x],err_file[y],jpg_file[x].replace("photo","CH#"+y+"_photo")); } } } }

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  • How do I disable touchpad tap to click?

    - by AWE
    You've heard this a million times but the "tap to click" is a pain in the behind and I want to disable it. There is no touchpad in gpointing-device-settings and neither in mouse and touchpad in system settings. I've tried some commands in terminal but it's all crap. Dconf-editor doesn't react. How about solving this once and for all? xinput list: ? Virtual core pointer id=2 [master pointer (3)] ? ? Virtual core XTEST pointer id=4 [slave pointer (2)] ? ? PS/2 Generic Mouse id=13 [slave pointer (2)] ? Virtual core keyboard id=3 [master keyboard (2)] ? Virtual core XTEST keyboard id=5 [slave keyboard (3)] ? Power Button id=6 [slave keyboard (3)] ? Video Bus id=7 [slave keyboard (3)] ? Video Bus id=8 [slave keyboard (3)] ? Power Button id=9 [slave keyboard (3)] ? Sleep Button id=10 [slave keyboard (3)] ? Laptop_Integrated_Webcam_HD id=11 [slave keyboard (3)] ? AT Translated Set 2 keyboard id=12 [slave keyboard (3)] ? Dell WMI hotkeys id=14 [slave keyboard (3)]

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  • Disable touchpad tap to click on Oneiric ocelot

    - by AWE
    You've heard this a million times but the "tap to click" is a pain in the behind and I want to disable it. There is no touchpad in gpointing-device-settings and neither in mouse and touchpad in system settings. I've tried some commands in terminal but it's all crap. Dconf-editor doesn't react. How about solving this once and for all? xinput list: ? Virtual core pointer id=2 [master pointer (3)] ? ? Virtual core XTEST pointer id=4 [slave pointer (2)] ? ? PS/2 Generic Mouse id=13 [slave pointer (2)] ? Virtual core keyboard id=3 [master keyboard (2)] ? Virtual core XTEST keyboard id=5 [slave keyboard (3)] ? Power Button id=6 [slave keyboard (3)] ? Video Bus id=7 [slave keyboard (3)] ? Video Bus id=8 [slave keyboard (3)] ? Power Button id=9 [slave keyboard (3)] ? Sleep Button id=10 [slave keyboard (3)] ? Laptop_Integrated_Webcam_HD id=11 [slave keyboard (3)] ? AT Translated Set 2 keyboard id=12 [slave keyboard (3)] ? Dell WMI hotkeys id=14 [slave keyboard (3)]

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  • Explain this C# code: byte* p = (byte*) (void*) Scan0;

    - by qulzam
    I found the code from the net in which i cant understand this line:- byte* p = (byte*)(void*)Scan0; There Scan0 is System.IntPtr. It is code of C#.Net. Plz Explain the above line. The complete code is given below. this is code to convert a image in grayscale. public static Image GrayScale(Bitmap b) { BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); int stride = bmData.Stride; System.IntPtr Scan0 = bmData.Scan0; unsafe { byte* p = (byte*)(void*)Scan0; int nOffset = stride - b.Width * 3; byte red, green, blue; for (int y = 0; y < b.Height; ++y) { for (int x = 0; x < b.Width; ++x) { blue = p[0]; green = p[1]; red = p[2]; p[0] = p[1] = p[2] = (byte)(.299 * red + .587 * green + .114 * blue); p += 3; } p += nOffset; } } b.UnlockBits(bmData); return (Image)b; } I understand all the code but only have the problem on this line. byte* p = (byte*)(void*)Scan0;

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  • error: a NUL byte in commit log message not allowed [migrated]

    - by James
    I'm trying to commit some files in my Git repository, and I'm receiving this error. This all started when I ran git rm -rf folder and git rm -rf file and tried to commit the changes. I've since been able to commit and push without these files being deleted from my remote repository, however I'm now completely stuck. The full error is: error: a NUL byte in commit log message not allowed. fatal: failed to write commit object What can I do to fix this? My Google-fu has let me down on this one. Edit: I've just checked out these deleted files, and attempted to commit again, but it's still giving me the same error. Has my Git repo been corrupted or something?

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  • Mounting NFS directory causes creating Zero byte files

    - by Alaa
    I have two Servers, Server X (IP 192.168.1.1) and Server Y (IP 192.168.1.2), both of them are ubuntu 9.1 i have created varnish load balancer on them for my drupal website (pressflow 6.22) I have mounted a directory of imagecache from server X to Y as below @X:/etc/exports == /var/www/proj/htdocs/sites/default/files/images 192.168.1.2(rw,async,no_subtree_check) @Y:/etc/fstab == 192.168.1.1:/var/www/proj/htdocs/sites/default/files/images var/www/proj/htdocs/sites/default/files/images nfs defaults 0 0 also i made this on server X X:/var/www/proj/htdocs/sites/default/files$ chmod -R 777 images i tried to touch, rm, vim, and cat files in images directory that has been mounted on Y and everything went fine. now, ALWAYS when server Y's imagecache tries to create an image in images directory, the image is created with ZERO byte file size. anyone face the same before? any idea of how to fix this problem or what might cause it? Thanks for your help

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  • Erlang: starting slave node

    - by Zim
    Hi, I'm trying to start erlang slave node on cluster and I receive "bash: erl: command not found" message. Though I have alias for erl. Here is what I actually do: [user@n001 ~]$ erl -rsh ssh -sname n001 Eshell V5.7.5 (abort with ^G) (n001@n001)1> slave:start_link("user@n002", n002, "-rsh ssh"). bash: erl: command not found {error,timeout} (n001@n001)2> Maybe, there is something wrong? Thanks.

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  • How do you access byte level information in JavaScript?

    - by JustSmith
    The generally accepted answer is that you can't. However there is mounting evidence that this is not true based on the existence of projects that read in types of data that are not basic HTML types. Some projects that do this are the JavaScript version of ProtoBuf and Smokescreen. Smokescreen is a flash interpreter written in JS so if it is not possible to get at the bytes directly how are these projects working around this? The source to Smokescreen can be found here. I have looked it over but with JS not being my primary language right now the solution eludes me.

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  • Mesos slave not 'Running' multiple executors simultaneously

    - by user3084164
    I am using Mesos to distribute a bunch of tasks to different machines (mesos-slaves). Here is what happens: 1. My scheduler gets resource offers and accepts it. 2. Mesos stages multiple executors on the same mesos-slaves (each slave has 4 cpus) 3. Only ONE executor enters the 'Running' state on each of the slaves while the others are shown in 'Staging' state. 4. Only after the current executor finishes execution the other executor starts running. Given that I have 4 CPUs on each machine, shouldn't each slave be running 4 executors simultaneously? Each executor requires 1 CPU.

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  • Configuring Multi-Tap on Synaptics Touchpad

    - by nunos
    I am having a hard time configuring my notebook's touchpad. The touchpad already works. It successfully responds to one-finger tap, two-finger tap and two-finger vertical scrolling. What I want to accomplish: change two-finger tap action from right-mouse click to middle-mouse click add three-finger tap functionality to yield right-mouse click action (i have checked that the three-finger tap is supported by my laptop's touchpad since it works on Windows) I read on a forum to use this as a guide. I have successfully accomplished point 1 with synclient TapButton2=2. However, I have to do it everytime I log in. I have tried to put that command on /etc/rc.local but the computer always boots and logins with the default configuration. Regarding point 2, I have tried synclient TapButton3=3 but it doesn't do anything when I three-finger tap the touchpad. I am running Ubuntu 11.10 on an Asus N82JV. /etc/X11/xorg.conf: nuno@mozart:~$ cat /etc/X11/xorg.conf Section "InputClass" Identifier "touchpad catchall" Driver "synaptics" MatchIsTouchpad "on" MatchDevicePath "/dev/input/event*" Option "TapButton1" "1" Option "TapButton2" "2" Option "TapButton3" "3" EndSection /usr/share/X11/xorg.conf.d/50-synaptics.conf: nuno@mozart:~$ cat /usr/share/X11/xorg.conf.d/50-synaptics.conf # Example xorg.conf.d snippet that assigns the touchpad driver # to all touchpads. See xorg.conf.d(5) for more information on # InputClass. # DO NOT EDIT THIS FILE, your distribution will likely overwrite # it when updating. Copy (and rename) this file into # /etc/X11/xorg.conf.d first. # Additional options may be added in the form of # Option "OptionName" "value" # Section "InputClass" Identifier "touchpad catchall" Driver "synaptics" MatchIsTouchpad "on" MatchDevicePath "/dev/input/event*" Option "TapButton1" "1" Option "TapButton2" "2" Option "TapButton3" "3" EndSection xinput list: nuno@mozart:~$ xinput list ? Virtual core pointer id=2 [master pointer (3)] ? ? Virtual core XTEST pointer id=4 [slave pointer (2)] ? ? Microsoft Microsoft® Nano Transceiver v2.0 id=12 [slave pointer (2)] ? ? Microsoft Microsoft® Nano Transceiver v2.0 id=13 [slave pointer (2)] ? ? ETPS/2 Elantech Touchpad id=16 [slave pointer (2)] ? Virtual core keyboard id=3 [master keyboard (2)] ? Virtual core XTEST keyboard id=5 [slave keyboard (3)] ? Power Button id=6 [slave keyboard (3)] ? Video Bus id=7 [slave keyboard (3)] ? Video Bus id=8 [slave keyboard (3)] ? Sleep Button id=9 [slave keyboard (3)] ? USB2.0 2.0M UVC WebCam id=10 [slave keyboard (3)] ? Microsoft Microsoft® Nano Transceiver v2.0 id=11 [slave keyboard (3)] ? Asus Laptop extra buttons id=14 [slave keyboard (3)] ? AT Translated Set 2 keyboard id=15 [slave keyboard (3)]

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  • Configuring Multi-Tap on Synpaptics Touchpad

    - by nunos
    I am having a hard time configuring my notebook's touchpad. The touchpad already works. It succesfully responds to one-finger tap, two-finger tap and two-finger vertical scrolling. What I want to accomplish: change two-finger tap action from right-mouse click to middle-mouse click add three-finger tap functionality to yield right-mouse click action I read on a forum to use this as a guide. I have succesfully accomplished point 1 with synclient TapButton2=2. However, I have to do it everytime I log in. I have tried to put that command on /etc/rc.local but the computer always boots and logins with the default configuration. Regarding point 2, I have tried synclient TapButton3=3 but it doesn't do anything when I three-finger tap the touchpad. I am running Ubuntu 11.10 on an Asus N82JV. /etc/X11/xorg.conf: nuno@mozart:~$ cat /etc/X11/xorg.conf Section "InputClass" Identifier "touchpad catchall" Driver "synaptics" MatchIsTouchpad "on" MatchDevicePath "/dev/input/event*" Option "TapButton1" "1" Option "TapButton2" "2" Option "TapButton3" "3" EndSection /usr/share/X11/xorg.conf.d/50-synaptics.conf: nuno@mozart:~$ cat /usr/share/X11/xorg.conf.d/50-synaptics.conf # Example xorg.conf.d snippet that assigns the touchpad driver # to all touchpads. See xorg.conf.d(5) for more information on # InputClass. # DO NOT EDIT THIS FILE, your distribution will likely overwrite # it when updating. Copy (and rename) this file into # /etc/X11/xorg.conf.d first. # Additional options may be added in the form of # Option "OptionName" "value" # Section "InputClass" Identifier "touchpad catchall" Driver "synaptics" MatchIsTouchpad "on" MatchDevicePath "/dev/input/event*" Option "TapButton1" "1" Option "TapButton2" "2" Option "TapButton3" "3" EndSection xinput list: nuno@mozart:~$ xinput list ? Virtual core pointer id=2 [master pointer (3)] ? ? Virtual core XTEST pointer id=4 [slave pointer (2)] ? ? Microsoft Microsoft® Nano Transceiver v2.0 id=12 [slave pointer (2)] ? ? Microsoft Microsoft® Nano Transceiver v2.0 id=13 [slave pointer (2)] ? ? ETPS/2 Elantech Touchpad id=16 [slave pointer (2)] ? Virtual core keyboard id=3 [master keyboard (2)] ? Virtual core XTEST keyboard id=5 [slave keyboard (3)] ? Power Button id=6 [slave keyboard (3)] ? Video Bus id=7 [slave keyboard (3)] ? Video Bus id=8 [slave keyboard (3)] ? Sleep Button id=9 [slave keyboard (3)] ? USB2.0 2.0M UVC WebCam id=10 [slave keyboard (3)] ? Microsoft Microsoft® Nano Transceiver v2.0 id=11 [slave keyboard (3)] ? Asus Laptop extra buttons id=14 [slave keyboard (3)] ? AT Translated Set 2 keyboard id=15 [slave keyboard (3)]

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