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• Possibility of initiating playback of flash video on headless server through the terminal

  - by brendan morrison

  Hey so I have a website which has video's gathered from places around the web, primarily youtube but a few other's as well. Now I am wondering if there is some way to check link's to make sure they are still available through a unix shell. (My idea is to run a cron to check videos are still available and if not delete them.) I am aware i could use user to do this but it always bothered me and was wondering if there is somehow to check the playback of a flash video though the terminal . Any insight into this would be awesome as I haven't found much on the web. Also note ideally the tech. will work on all video type's including html5. update So it's occured to me that through the you tube api, I could check the status of the video's coming from youtube (which is a start). But I would love to know if there's something else that is not player specific but rather just calls the video to play similar to how a user would.

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• Oracle sort Solaris 11.1 et Solaris Cluster 4.1, l'OS Unix apporte plus de 300 nouvelles fonctionnalités et étend ses capacités Cloud

  Oracle Solaris 11.1 étend ses capacités Cloud le système d'exploitation Unix sort avec plus de 300 nouvelles fonctionnalités Oracle vient de présenter Solaris 11.1, la nouvelle mise à jour majeure de son système d'exploitation Unix. Cette mouture apporte plus de 300 nouvelles fonctionnalités et améliorations à la famille des produits Oracle Solaris 11. Oracle Solaris 11 est un système d'exploitation particulièrement optimisé pour la ligne des serveurs Oracle SPARC T-Series, Oracle SPARC SuperCluster T4-4, les machines Oracle Exadata Database et la solution de Cloud Oracle Exalogic Elastic Cloud engineered systems. Oracle Solaris 11 mise essentiellement sur le Cloud ...

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• Oracle Solaris 11.1 étend ses capacités Cloud, le système d'exploitation Unix sort avec plus de 300 nouvelles fonctionnalités

  Oracle Solaris 11.1 étend ses capacités Cloud le système d'exploitation Unix sort avec plus de 300 nouvelles fonctionnalités Oracle vient d'annoncer la sortie de Solaris 11.1, la nouvelle mise à jour majeure de son système d'exploitation Unix. Cette mouture apporte plus de 300 nouvelles fonctionnalités et améliorations à la famille des produits Oracle Solaris 11. Oracle Solaris 11 est un système d'exploitation particulièrement optimisé pour la ligne des serveurs Oracle SPARC T-Series, Oracle SPARC SuperCluster T4-4, les machines Oracle Exadata Database et la solution de Cloud Oracle Exalogic Elastic Cloud engineered systems. Oracle Solaris 11 mise essentiellement su...

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• how could installations/configurations be easier in linux?

  - by ajsie

  although you can do anything in linux it tends to require a lot of tweaking in config files and reading a lot of manuals/tutorials before you can have it running in your way. i know that it gets a lot easier by time, and the apt-get installations with ubuntu/debian is heading the right way. but how can linux be more userfriendly for us in the future? i thought that if more is automated like an IDE environment, eg. typing svn will give us all the commands and description about each command when you move between commands with your keyboard. that would be great. but that's just one example. another is the navigation in the terminal between folders. now you have to type a lot just to jump from/to different folders. would be great with some more automatization here too. i know that these extra features will slow down the server, but its 2010 now, and these features are not that heavy for the cpu, but makes it more userfriendly and encourage maintainance of a server, not frighten u off. what do you think about this? should/could we have more user friendly linux environment in servers, something that has annoyed you a lot? a lot of things are done in the unix way, but maybe we should reinvent the wheel in some areas, cause apparently, its so...repeatingly today and difficult to do easy tasks. it should be easier i think..

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• What is the difference between AF_INET and PF_INET constants?

  - by Denilson Sá

  Looking at examples about socket programming, we can see that some people use AF_INET while others use PF_INET. In addition, sometimes both of them are used at the same example. The question is: Is there any difference between them? Which one should we use? If you can answer that, another question would be... Why there are these two similar (but equal) constants? What I've discovered, so far: The socket manpage In (Unix) socket programming, we have the socket() function that receives the following parameters: int socket(int domain, int type, int protocol); The manpage says: The domain argument specifies a communication domain; this selects the protocol family which will be used for communication. These families are defined in <sys/socket.h>. And the manpage cites AF_INET as well as some other AF_ constants for the domain parameter. Also, at the NOTES section of the same manpage, we can read: The manifest constants used under 4.x BSD for protocol families are PF_UNIX, PF_INET, etc., while AF_UNIX etc. are used for address families. However, already the BSD man page promises: "The protocol family generally is the same as the address family", and subsequent standards use AF_* everywhere. The C headers The sys/socket.h does not actually define those constants, but instead includes bits/socket.h. This file defines around 38 AF_ constants and 38 PF_ constants like this: #define PF_INET 2 /* IP protocol family. */ #define AF_INET PF_INET Python The Python socket module is very similar to the C API. However, there are many AF_ constants but only one PF_ constant (PF_PACKET). Thus, in Python we have no choice but use AF_INET. I think this decision to include only the AF_ constants follows one of the guiding principles: "There should be one-- and preferably only one --obvious way to do it." (The Zen of Python)

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• How to make new file permission inherit from the parent directory?

  - by Wai Yip Tung

  I have a directory called data. Then I am running a script under the user id 'robot'. robot writes to the data directory and update files inside. The idea is data is open for both me and robot to update. So I setup the permission and owner group like this drwxrwxr-x 2 me robot-grp 4096 Jun 11 20:50 data where both me and robot belongs to the 'robot-grp'. I change the permission and the owner group recursively like the parent directory. I regularly upload new files into the data directory using rsync. Unfortunately, new files uploaded does not inherit the parent directory's permission as I hope. Instead it looks like this -rw-r--r-- 1 me users 6 Jun 11 20:50 new-file.txt When robot tries to update new-file.txt, it fails due to lack of file permission. I'm not sure if setting umask helps. In anycase the new files does not really follow it. $ umask -S u=rwx,g=rx,o=rx I'm often confounded by Unix file permission. Do I even have a right plan? I'm using Debian lenny.

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• what webserver / mod / technique should I use to serve everything from memory?

  - by reinier

  I've lots of lookuptables from which I'll generate my webresponse. I think IIS with Asp.net enables me to keep static lookuptables in memory which I can use to serve up my responses very fast. Are there however also non .net solutions which can do the same? I've looked at fastcgi, but I think this starts X processes, of which anyone can handle Y requests. But the processes are by definition shielded from eachother. I could configure fastcgi to use just 1 process, but does this have scalability implications? anything using PHP or any other interpreted language won't fly because it is also cgi or fastcgi bound right? I understand memcache could be an option, though this would require another (local) socket connection which I'd rather avoid since everything in memory would be much faster. The solution can work under WIndows or Unix... it doesn't matter too much. The only thing which matters is that there will be a lot of requests (100/sec now and growing to 500/sec in a year), and I want to reduce the amount of webservers needed to process it. The current solution is done using PHP and memcache (and the occasional hit to the SQL server backend). Although it is fast (for php anyway), Apache has real problems when the 50/sec is passed. I've put a bounty on this question since I've not seen enough responses to make a wise choice. At the moment I'm considering either Asp.net or fastcgi with C(++).

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• confusing fork system call

  - by benjamin button

  Hi, i was just checking the behaviour of fork system call and i found it very confusing. i saw in a website that Unix will make an exact copy of the parent's address space and give it to the child. Therefore, the parent and child processes have separate address spaces #include <stdio.h> #include <sys/types.h> int main(void) { pid_t pid; char y='Y'; char *ptr; ptr=&y; pid = fork(); if (pid == 0) { y='Z'; printf(" *** Child process ***\n"); printf(" Address is %p\n",ptr); printf(" char value is %c\n",y); sleep(5); } else { sleep(5); printf("\n ***parent process ***\n",&y); printf(" Address is %p\n",ptr); printf(" char value is %c\n",y); } } the output of the above program is : *** Child process *** Address is 69002894 char value is Z ***parent process *** Address is 69002894 char value is Y so from the above mentioned statement it seems that child and parent have separet address spaces.this is the reason why char value is printed separately and why am i seeing the address of the variable as same in both child and parent processes.? Please help me understand this!

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• how could application installations/configurations be easier in linux? [closed]

  - by ajsie

  although you can do anything in linux it tends to require a lot of tweaking in config files and reading a lot of manuals/tutorials before you can have it running in your way. i know that it gets a lot easier by time, and the apt-get installations with ubuntu/debian is heading the right way. but how can linux be more userfriendly for us in the future? i thought that if more is automated like an IDE environment, eg. typing svn will give us all the commands and description about each command when you move between commands with your keyboard. that would be great. but that's just one example. another is the navigation in the terminal between folders. now you have to type a lot just to jump from/to different folders. would be great with some more automatization here too. i know that these extra features will slow down the server, but its 2010 now, and these features are not that heavy for the cpu, but makes it more userfriendly and encourage maintainance of a server, not frighten u off. what do you think about this? should/could we have more user friendly linux environment in servers, something that has annoyed you a lot? a lot of things are done in the unix way, but maybe we should reinvent the wheel in some areas, cause apparently, its so...repeatingly today and difficult to do easy tasks. it should be easier i think..

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• How can I obtain the local TCP port and IP Address of my client program?

  - by Dr Dork

  Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain the local IP address and dynamically assigned TCP port of the client. The function I've found to do this is getsockname()... //setup the socket if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("client: socket"); continue; } //Retrieve the locally-bound name of the specified socket and store it in the sockaddr structure sa_len = sizeof(sa); getsock_check = getsockname(sockfd,(struct sockaddr *)&sa,(socklen_t *)&sa_len) ; if (getsock_check== -1) { perror("getsockname"); exit(1); } printf("Local IP address is: %s\n", inet_ntoa(sa.sin_addr)); printf("Local port is: %d\n", (int) ntohs(sa.sin_port)); but the output is always zero... Local IP address is: 0.0.0.0 Local port is: 0 does anyone see anything I might be or am definitely doing wrong? Thanks so much in advance for all your help!

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• What does it mean for an OS to "execute within user processes"? Do any modern OS's use that approach

  - by Chris Cooper

  I have recently become interested in operating system, and a friend of mine lent me a book called Operating Systems: Internals and Design Principles (I have the third edition), published in 1998. It's been a very interesting book so far, but I have come to the part dealing with process control, and it's using UNIX System V as one of its examples of an operating system that executes within user processes. This concept has struck me as a little strange. First of all, does this mean that OS instructions and data are stored in each user of the processes? Probably not, because that would be an absurdly redundant scheme. But if not, then what does it mean to "execute within" a user process? Do any modern operating systems use this approach? It seems much more logical to have the operating system execute as its own process, or even independently of all processes, if you're short on memory. All the inter-accessiblilty of process data required for this layout seems to greatly complicate things. (But maybe that's just because I don't quite get the concept ;D) Here is what the book says: "Execution within User Processes: An alternative that is common with operation systems on smaller machines is to execute virtually all operating system software in the context of a user process. ... "

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• BASH: How to count all the human readable files?

  - by user1687406

  I'm taking an intro course to UNIX and have a homework question that follows: How many files in the previous question are text files? A text file is any file containing human-readable content. (TRICK QUESTION. Run the file command on a file to see whether the file is a text file or a binary data file! If you simply count the number of files with the ".txt" extension you will get no points for this question.) The previous question simply asked how many regular files there were, which was easy to figure out by doing find . -type f | wc -l I'm just having trouble determining what "human readable content" is, since I'm assuming it means anything besides binary/assembly, but I thought that's what -type f displays. Maybe that's what the professor meant by saying "trick question"? This question has a follow up later that also asks "What text files contain the string "csc" in any mix of upper and lower case?". Obviously "text" is referring to more than just .txt files, but I need to figure out the first question to determine this!

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• Extracting word from file using grep or sed

  - by Marco

  Hi, I have a file in the format below: File : \\dvtbbnkapp115\nautilus\030db28a-f241-4054-a0e3-9bfa7e002535.dip was processed. Entries Found : 0 Unarchived Documents : 1 File Size : 1 K Error : The following line could not be processed. Bad Document Type. Error : Marketing and Contact preference change update||7000003735||078ef1f3-db6b-46a8-bb0d-c40bb2296ab5.pdf File : \\dvtbbnkapp115\nautilus\078ef1f3-db6b-46a8-bb0d-c40bb2296ab5.dip was processed. Entries Found : 0 Unarchived Documents : 1 File Size : 1 K Error : The following line could not be processed. Bad Document Type. Error : Declined - Bureau Data (process)||7000003723|252204|2f1d71f4-052c-49f1-95cf-9ca9b4268f0c.pdf File : \\dvtbbnkapp115\nautilus\2f1d71f4-052c-49f1-95cf-9ca9b4268f0c.dip was processed. Entries Found : 0 Unarchived Documents : 1 File Size : 1 K Error : The following line could not be processed. Bad Document Type. Error : Unable to call - please contact|40640510016710|7000003180||3e6a792f-c136-4a4b-a654-37f4476ccef8.pdf I require to extract just the pdf file names after the double pipe and write them to a file. I am a novice when it comes to unix/sed/grep commands, i have tried but no luck? any ideas or examples i could use to extract the information above? thanks

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• How do I cover unintuitive code blocks?

  - by naivedeveloper

  For some reason, I'm having a hard time trying to cover the block of code below. This code is an excerpt from the UNIX uniq command. I'm trying to write test cases to cover all blocks, but can't seem to reach this block: if (nfiles == 2) { // Generic error routine } In context: int main (int argc, char **argv) { int optc = 0; bool posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL); int nfiles = 0; char const *file[2]; file[0] = file[1] = "-"; program_name = argv[0]; skip_chars = 0; skip_fields = 0; check_chars = SIZE_MAX; for (;;) { /* Parse an operand with leading "+" as a file after "--" was seen; or if pedantic and a file was seen; or if not obsolete. */ if (optc == -1 || (posixly_correct && nfiles != 0) || ((optc = getopt_long (argc, argv, "-0123456789Dcdf:is:uw:", longopts, NULL)) == -1)) { if (optind == argc) break; if (nfiles == 2) { // Handle errors } file[nfiles++] = argv[optind++]; } else switch (optc) { case 1: { unsigned long int size; if (optarg[0] == '+' && posix2_version () < 200112 && xstrtoul (optarg, NULL, 10, &size, "") == LONGINT_OK && size <= SIZE_MAX) skip_chars = size; else if (nfiles == 2) { // Handle error } else file[nfiles++] = optarg; } break; } } } Any help would be greatly appreciated. Thanks.

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• What can cause a spontaneous EPIPE error without either end calling close() or crashing?

  - by Hongli

  I have an application that consists of two processes (let's call them A and B), connected to each other through Unix domain sockets. Most of the time it works fine, but some users report the following behavior: A sends a request to B. This works. A now starts reading the reply from B. B sends a reply to A. The corresponding write() call returns an EPIPE error, and as a result B close() the socket. However, A did not close() the socket, nor did it crash. A's read() call returns 0, indicating end-of-file. A thinks that B prematurely closed the connection. Users have also reported variations of this behavior, e.g.: A sends a request to B. This works partially, but before the entire request is sent A's write() call returns EPIPE, and as a result A close() the socket. However B did not close() the socket, nor did it crash. B reads a partial request and then suddenly gets an EOF. The problem is I cannot reproduce this behavior locally at all. I've tried OS X and Linux. The users are on a variety of systems, mostly OS X and Linux. Things that I've already tried and considered: Double close() bugs (close() is called twice on the same file descriptor): probably not as that would result in EBADF errors, but I haven't seen them. Increasing the maximum file descriptor limit. One user reported that this worked for him, the rest reported that it did not. What else can possibly cause behavior like this? I know for certain that neither A nor B close() the socket prematurely, and I know for certain that neither of them have crashed because both A and B were able to report the error. It is as if the kernel suddenly decided to pull the plug from the socket for some reason.

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• Commons VFS and IBM MVS System

  - by Liming

  Hello All, I'm using Apache Commons VFS / SFTP, we are trying to download files from the IBM MVS system. The download part is all good, however, we can not open up the zipped files after downloading. Seems like the zip file was compressed using a different algorithm or something Anyone has any pointers? *Note, the same function works fine if we connect to a regular unix/linux SFTP server. Below is an example of what we did String defaultHost = "[my sftp ip address]"; String host = defaultHost; String defaultRemotePath = "//__root.dir1.dir2."; String remotePath = defaultRemotePath; String user = "test"; String password = "test"; String remoteFileName = "Blah.ZIP.BLAH"; log.info("FtpPojo() begin instantiation"); FileObject localFileObject = fsManager.resolveFile("C:/Work/Blah.ZIP.BLAH"); log.debug("local file name is :"+localFileObject.getName().getBaseName()); log.debug("FtpPojo() instantiated and fsManager created"); String uri = createSftpUri(host, user, password) + ":322"+remotePath+remoteFileName; remoteRepo = fsManager.resolveFile(uri, fsOptions); remoteRepo.copyFrom(localFileObject, Selectors.SELECT_ALL);

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• Utility that helps in file locking - expert tips wanted

  - by maix

  I've written a subclass of file that a) provides methods to conveniently lock it (using fcntl, so it only supports unix, which is however OK for me atm) and b) when reading or writing asserts that the file is appropriately locked. Now I'm not an expert at such stuff (I've just read one paper [de] about it) and would appreciate some feedback: Is it secure, are there race conditions, are there other things that could be done better … Here is the code: from fcntl import flock, LOCK_EX, LOCK_SH, LOCK_UN, LOCK_NB class LockedFile(file): """ A wrapper around `file` providing locking. Requires a shared lock to read and a exclusive lock to write. Main differences: * Additional methods: lock_ex, lock_sh, unlock * Refuse to read when not locked, refuse to write when not locked exclusivly. * mode cannot be `w` since then the file would be truncated before it could be locked. You have to lock the file yourself, it won't be done for you implicitly. Only you know what lock you need. Example usage:: def get_config(): f = LockedFile(CONFIG_FILENAME, 'r') f.lock_sh() config = parse_ini(f.read()) f.close() def set_config(key, value): f = LockedFile(CONFIG_FILENAME, 'r+') f.lock_ex() config = parse_ini(f.read()) config[key] = value f.truncate() f.write(make_ini(config)) f.close() """ def __init__(self, name, mode='r', *args, **kwargs): if 'w' in mode: raise ValueError('Cannot open file in `w` mode') super(LockedFile, self).__init__(name, mode, *args, **kwargs) self.locked = None def lock_sh(self, **kwargs): """ Acquire a shared lock on the file. If the file is already locked exclusively, do nothing. :returns: Lock status from before the call (one of 'sh', 'ex', None). :param nonblocking: Don't wait for the lock to be available. """ if self.locked == 'ex': return # would implicitly remove the exclusive lock return self._lock(LOCK_SH, **kwargs) def lock_ex(self, **kwargs): """ Acquire an exclusive lock on the file. :returns: Lock status from before the call (one of 'sh', 'ex', None). :param nonblocking: Don't wait for the lock to be available. """ return self._lock(LOCK_EX, **kwargs) def unlock(self): """ Release all locks on the file. Flushes if there was an exclusive lock. :returns: Lock status from before the call (one of 'sh', 'ex', None). """ if self.locked == 'ex': self.flush() return self._lock(LOCK_UN) def _lock(self, mode, nonblocking=False): flock(self, mode | bool(nonblocking) * LOCK_NB) before = self.locked self.locked = {LOCK_SH: 'sh', LOCK_EX: 'ex', LOCK_UN: None}[mode] return before def _assert_read_lock(self): assert self.locked, "File is not locked" def _assert_write_lock(self): assert self.locked == 'ex', "File is not locked exclusively" def read(self, *args): self._assert_read_lock() return super(LockedFile, self).read(*args) def readline(self, *args): self._assert_read_lock() return super(LockedFile, self).readline(*args) def readlines(self, *args): self._assert_read_lock() return super(LockedFile, self).readlines(*args) def xreadlines(self, *args): self._assert_read_lock() return super(LockedFile, self).xreadlines(*args) def __iter__(self): self._assert_read_lock() return super(LockedFile, self).__iter__() def next(self): self._assert_read_lock() return super(LockedFile, self).next() def write(self, *args): self._assert_write_lock() return super(LockedFile, self).write(*args) def writelines(self, *args): self._assert_write_lock() return super(LockedFile, self).writelines(*args) def flush(self): self._assert_write_lock() return super(LockedFile, self).flush() def truncate(self, *args): self._assert_write_lock() return super(LockedFile, self).truncate(*args) def close(self): self.unlock() return super(LockedFile, self).close() (the example in the docstring is also my current use case for this) Thanks for having read until down here, and possibly even answering :)

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• Any socket programmers out there? How can I obtain the IPv4 address of the client?

  - by Dr Dork

  Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code setup to listen for incoming TCP connection requests from clients after the parent socket has been created and is set to listen... int sockfd, newfd; unsigned int len; socklen_t sin_size; char msg[]="Test message sent"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char ip[INET6_ADDRSTRLEN]; . . //parent socket creation and listen code omitted for simplicity . //wait for connection requests from clients while(1) { //Returns the socketID and address of client connecting to socket if( ( newfd = accept(sockfd, (struct sockaddr *)&client, &len) ) == -1 ){ perror("Accept"); exit(-1); } if( (rv = recv(newfd, buf, MAXLEN-1, 0 )) == -1) { perror("Recv"); exit(-1); } struct sockaddr_in *clientAddr = ( struct sockaddr_in *) get_in_addr((struct sockaddr *)&client); inet_ntop(client.ss_family, clientAddr, ip, sizeof ip); printf("Receive from %s: query type is %s\n", ip, buf); if( ( st = send(newfd, msg, strlen(msg), 0)) == -1 ) { perror("Send"); exit(-1); } //ntohs is used to avoid big-endian and little endian compatibility issues printf("Send %d byte to port %d\n", ntohs(clientAddr->sin_port) ); close(newfd); } } I found the get_in_addr function online and placed it at the top of my code and use it to obtain the IP address of the client connecting... // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); } return &(((struct sockaddr_in6*)sa)->sin6_addr); } but the function always returns the IPv6 IP address since thats what the sa_family property is set as. My question is, is the IPv4 IP address stored anywhere in the data I'm using and, if so, how can I access it? Thanks so much in advance for all your help!

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• printf anomaly after "fork()"

  - by pechenie

  OS: Linux, Language: pure C I'm moving forward in learning C progpramming in general, and C programming under UNIX in a special case :D So, I detected a strange (as for me) behaviour of the printf() function after using a fork() call. Let's take a look at simple test program: #include <stdio.h> #include <system.h> int main() { int pid; printf( "Hello, my pid is %d", getpid() ); pid = fork(); if( pid == 0 ) { printf( "\nI was forked! :D" ); sleep( 3 ); } else { waitpid( pid, NULL, 0 ); printf( "\n%d was forked!", pid ); } return 0; } In this case the output looks like: Hello, my pid is 1111 I was forked! :DHello, my pid is 1111 2222 was forked! Why the second "Hello" string occured in the child's output? Yes, it is exactly what the parent printed on it's start, with the parent's pid. But! If we place '\n' character in the end of each string we got the expected output: #include <stdio.h> #include <system.h> int main() { int pid; printf( "Hello, my pid is %d\n", getpid() ); // SIC!! pid = fork(); if( pid == 0 ) { printf( "I was forked! :D" ); //removed the '\n', no matter sleep( 3 ); } else { waitpid( pid, NULL, 0 ); printf( "\n%d was forked!", pid ); } return 0; } And the output looks like: Hello, my pid is 1111 I was forked! :D 2222 was forked! Why does it happen? Is it ... ummm ... correct behaviour? Or it's a kind of the 'bug'?

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• How can I obtain the IPv4 address of the client?

  - by Dr Dork

  Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code setup to listen for incoming TCP connection requests from clients after the parent socket has been created and is set to listen... int sockfd, newfd; unsigned int len; socklen_t sin_size; char msg[]="Test message sent"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char ip[INET6_ADDRSTRLEN]; . . //parent socket creation and listen code omitted for simplicity . //wait for connection requests from clients while(1) { //Returns the socketID and address of client connecting to socket if( ( newfd = accept(sockfd, (struct sockaddr *)&client, &len) ) == -1 ){ perror("Accept"); exit(-1); } if( (rv = recv(newfd, buf, MAXLEN-1, 0 )) == -1) { perror("Recv"); exit(-1); } struct sockaddr_in *clientAddr = ( struct sockaddr_in *) get_in_addr((struct sockaddr *)&client); inet_ntop(client.ss_family, clientAddr, ip, sizeof ip); printf("Receive from %s: query type is %s\n", ip, buf); if( ( st = send(newfd, msg, strlen(msg), 0)) == -1 ) { perror("Send"); exit(-1); } //ntohs is used to avoid big-endian and little endian compatibility issues printf("Send %d byte to port %d\n", ntohs(clientAddr->sin_port) ); close(newfd); } } I found the get_in_addr function online and placed it at the top of my code and use it to obtain the IP address of the client connecting... // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); } return &(((struct sockaddr_in6*)sa)->sin6_addr); } but the function always returns the IPv6 IP address since thats what the sa_family property is set as. My question is, is the IPv4 IP address stored anywhere in the data I'm using and, if so, how can I access it? Thanks so much in advance for all your help!

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• How can I obtain the IP address of my server program?

  - by Dr Dork

  Hello! This question is related to another question I just posted. I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain my server program's IP address. Here's the code I currently have to do this, but it's not working... int sockfd; unsigned int len; socklen_t sin_size; char msg[]="test message"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char s[INET6_ADDRSTRLEN]; char ip[INET6_ADDRSTRLEN]; //zero struct memset(&hints,0,sizeof(hints)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_PASSIVE; //get the server info if((rv = getaddrinfo(NULL, SERVERPORT, &hints, &serverinfo ) != 0)){ perror("getaddrinfo"); exit(-1); } // loop through all the results and bind to the first we can for( p = serverinfo; p != NULL; p = p->ai_next) { //Setup the socket if( (sockfd = socket( p->ai_family, p->ai_socktype, p->ai_protocol )) == -1 ) { perror("socket"); continue; } //Associate a socket id with an address to which other processes can connect if(bind(sockfd, p->ai_addr, p->ai_addrlen) == -1){ close(sockfd); perror("bind"); continue; } break; } if( p == NULL ){ perror("Fail to bind"); } inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof(s)); printf("Server has TCP Port %s and IP Address %s\n", SERVERPORT, s); and the output for the IP is always empty... server has TCP Port 21412 and IP Address :: any ideas for what I'm missing? thanks in advance for your help! this stuff is really complicated at first.

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• How should I clean up hung grandchild processes when an alarm trips in Perl?

  - by brian d foy

  I have a parallelized automation script which needs to call many other scripts, some of which hang because they (incorrectly) wait for standard input. That's not a big deal because I catch those with alarm. The trick is to shut down those hung grandchild processes when the child shuts down. I thought various incantations of SIGCHLD, waiting, and process groups could do the trick, but they all block and the grandchildren aren't reaped. My solution, which works, just doesn't seem like it is the right solution. I'm not especially interested in the Windows solution just yet, but I'll eventually need that too. Mine only works for Unix, which is fine for now. I wrote a small script that takes the number of simultaneous parallel children to run and the total number of forks: $ fork_bomb <parallel jobs> <number of forks> $ fork_bomb 8 500 This will probably hit the per-user process limit within a couple of minutes. Many solutions I've found just tell you to increase the per-user process limit, but I need this to run about 300,000 times, so that isn't going to work. Similarly, suggestions to re-exec and so on to clear the process table aren't what I need. I'd like to actually fix the problem instead of slapping duct tape over it. I crawl the process table looking for the child processes and shut down the hung processes individually in the SIGALRM handler, which needs to die because the rest of real code has no hope of success after that. The kludgey crawl through the process table doesn't bother me from a performance perspective, but I wouldn't mind not doing it: use Parallel::ForkManager; use Proc::ProcessTable; my $pm = Parallel::ForkManager->new( $ARGV[0] ); my $alarm_sub = sub { kill 9, map { $_->{pid} } grep { $_->{ppid} == $$ } @{ Proc::ProcessTable->new->table }; die "Alarm rang for $$!\n"; }; foreach ( 0 .. $ARGV[1] ) { print "."; print "\n" unless $count++ % 50; my $pid = $pm->start and next; local $SIG{ALRM} = $alarm_sub; eval { alarm( 2 ); system "$^X -le '<STDIN>'"; # this will hang alarm( 0 ); }; $pm->finish; } If you want to run out of processes, take out the kill. I thought that setting a process group would work so I could kill everything together, but that blocks: my $alarm_sub = sub { kill 9, -$$; # blocks here die "Alarm rang for $$!\n"; }; foreach ( 0 .. $ARGV[1] ) { print "."; print "\n" unless $count++ % 50; my $pid = $pm->start and next; setpgrp(0, 0); local $SIG{ALRM} = $alarm_sub; eval { alarm( 2 ); system "$^X -le '<STDIN>'"; # this will hang alarm( 0 ); }; $pm->finish; } The same thing with POSIX's setsid didn't work either, and I think that actually broke things in a different way since I'm not really daemonizing this. Curiously, Parallel::ForkManager's run_on_finish happens too late for the same clean-up code: the grandchildren are apparently already disassociated from the child processes at that point.

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• Someone please help google create instuctions that windows users understand. googles "instructions"

  - by nathan

  Below are the only instructions i managed to find from google on how to install the android NDK, it is written as if we all run Linux and presumes we all understand what these obscure tools are. My comments and questions appear in Italics if somone who knows unix and windows would translate for google that would be great! Android NDK Installation Introduction: Please read docs/OVERVIEW.TXT to understand what the Android NDK is and is not. This file gives instructions on how to properly setup your NDK. I. Requirements: The Android NDK currently requires a Linux, OS X or Windows host operating system. Windows users will need to install Cygwin (http://www.cygwin.com) to use it. Note that running the NDK under MSys is not supported. You will need to have the Android SDK and its dependencies installed. The NDK cannot generate final application packages (.apk files), only the shared library files that can go into them. IMPORTANT: The Android NDK can only be used to target system images using the Cupcake (1.5) or later releases of the platform. This is due to subtle toolchain and ABI related changed that make it incompatible with 1.0 and 1.1 system images. The NDK requires GNU Make 3.81 or later being available on your development system. Earlier versions of GNU Make might work but have not been tested. You can check this by running 'make -v' from the command-line. The output should look like: GNU Make 3.81 Copyright (C) 2006 Free Software Foundation, Inc. ... On certain systems, GNU Make might be available through a different command like 'gmake' or 'gnumake'. For these systems, replace 'make' by the appropriate command when invoking the NDK build system as described in the documentation. Great some strange thing called gnu make.. if your not going to tell me what it does maybe you then at least you could give me a URL to it? The NDK also requires a Nawk or GNU Awk executable being available on your development system. Note that the original 'awk' program doesn't implement the 'match' and 'substr' functions used by the NDK build system. Ok another tool, with 1 of 2 possible names, but not the third... and again where should i download this?? On Windows, you will need to install a recent release of Cygwin to use the NDK. See http://www.cygwin.com for instructions. Woohoo a URL! download took about a day because these install instructions do not specify what parts to download. II. Preparing your installation prebuilt cross-toolchain binaries: After installing and unarchiving the NDK, you will need to run the following command from the root folder: build/host-setup.sh hello? windows dont run nothing but .exe .com or .dll, just tell me how you want me to run it.. This will test your setup and make sure the NDK can work properly. Nothing is said about where any of these things need to be installed to (what directory)

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• How do I maximize code coverage?

  - by naivedeveloper

  Hey all, the following is a snippet of code taken from the unix ptx utility. I'm attempting to maximize code coverage on this utility, but I am unable to reach the indicated portion of code. Admittedly, I'm not as strong in my C skills as I used to be. The portion of code is indicated with comments, but it is towards the bottom of the block. if (used_length == allocated_length) { allocated_length += (1 << SWALLOW_REALLOC_LOG); block->start = (char *) xrealloc (block->start, allocated_length); } Any help interpreting the indicated portion in order to cover that block would be greatly appreciated. /* Reallocation step when swallowing non regular files. The value is not the actual reallocation step, but its base two logarithm. */ #define SWALLOW_REALLOC_LOG 12 static void swallow_file_in_memory (const char *file_name, BLOCK *block) { int file_handle; /* file descriptor number */ struct stat stat_block; /* stat block for file */ size_t allocated_length; /* allocated length of memory buffer */ size_t used_length; /* used length in memory buffer */ int read_length; /* number of character gotten on last read */ /* As special cases, a file name which is NULL or "-" indicates standard input, which is already opened. In all other cases, open the file from its name. */ bool using_stdin = !file_name || !*file_name || strcmp (file_name, "-") == 0; if (using_stdin) file_handle = STDIN_FILENO; else if ((file_handle = open (file_name, O_RDONLY)) < 0) error (EXIT_FAILURE, errno, "%s", file_name); /* If the file is a plain, regular file, allocate the memory buffer all at once and swallow the file in one blow. In other cases, read the file repeatedly in smaller chunks until we have it all, reallocating memory once in a while, as we go. */ if (fstat (file_handle, &stat_block) < 0) error (EXIT_FAILURE, errno, "%s", file_name); if (S_ISREG (stat_block.st_mode)) { size_t in_memory_size; block->start = (char *) xmalloc ((size_t) stat_block.st_size); if ((in_memory_size = read (file_handle, block->start, (size_t) stat_block.st_size)) != stat_block.st_size) { error (EXIT_FAILURE, errno, "%s", file_name); } block->end = block->start + in_memory_size; } else { block->start = (char *) xmalloc ((size_t) 1 << SWALLOW_REALLOC_LOG); used_length = 0; allocated_length = (1 << SWALLOW_REALLOC_LOG); while (read_length = read (file_handle, block->start + used_length, allocated_length - used_length), read_length > 0) { used_length += read_length; /* Cannot cover from this point...*/ if (used_length == allocated_length) { allocated_length += (1 << SWALLOW_REALLOC_LOG); block->start = (char *) xrealloc (block->start, allocated_length); } /* ...to this point. */ } if (read_length < 0) error (EXIT_FAILURE, errno, "%s", file_name); block->end = block->start + used_length; } /* Close the file, but only if it was not the standard input. */ if (! using_stdin && close (file_handle) != 0) error (EXIT_FAILURE, errno, "%s", file_name); }

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• Internal Server Error with mod_wsgi [django] on windows xp

  - by sacabuche

  when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order allow,deny Allow from all </Directory> Alias /codevents/media C:/django/projects/CODEvents/html <Directory "C:/django/projects/CODEvents/html"> Order allow,deny Allow from all </Directory> in CODEvents.wsgi import os, sys sys.path.append('C:\\Python26\\Lib\\site-packages\\django') sys.path.append('C:\\django\\projects') sys.path.append('C:\\django\\apps') sys.path.append('C:\\django\\projects\\CODEvents') os.environ['DJANGO_SETTINGS_MODULE'] = 'CODEvents.settings' import django.core.handlers.wsgi application = django.core.handlers.wsgi.WSGIHandler() and in my error_log it said: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] mod_wsgi (pid=1848): Exception occurred processing WSGI script 'C:/django/apache/CODEvents.wsgi'. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Traceback (most recent call last): [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\wsgi.py", line 241, in __call__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] response = self.get_response(request) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 142, in get_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.handle_uncaught_exception(request, resolver, exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 166, in handle_uncaught_exception [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return debug.technical_500_response(request, *exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 58, in technical_500_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] html = reporter.get_traceback_html() [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 137, in get_traceback_html [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return t.render(c) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 173, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self._render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 167, in _render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.nodelist.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 796, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] bits.append(self.render_node(node, context)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 72, in render_node [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] result = node.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 89, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] output = self.filter_expression.resolve(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 579, in resolve [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] new_obj = func(obj, *arg_vals) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\defaultfilters.py", line 693, in date [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return format(value, arg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 281, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return df.format(format_string) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 187, in r [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.format('D, j M Y H:i:s O') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\encoding.py", line 66, in force_unicode [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] s = unicode(s) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 206, in __unicode_cast [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.__func(*self.__args, **self.__kw) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 55, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return real_ugettext(message) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 55, in _curried [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 36, in delayed_loader [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return getattr(trans, real_name)(*args, **kwargs) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 276, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return do_translate(message, 'ugettext') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 266, in do_translate [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] _default = translation(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 176, in translation [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] default_translation = _fetch(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 159, in _fetch [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] app = import_module(appname) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\importlib.py", line 35, in import_module [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] __import__(name) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\__init__.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.contrib.admin.helpers import ACTION_CHECKBOX_NAME [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\helpers.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django import forms [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\__init__.py", line 17, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from models import * [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\models.py", line 6, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.db import connections [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\__init__.py", line 75, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] connection = connections[DEFAULT_DB_ALIAS] [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 91, in __getitem__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] backend = load_backend(db['ENGINE']) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 49, in load_backend [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] raise ImproperlyConfigured(error_msg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] TemplateSyntaxError: Caught ImproperlyConfigured while rendering: 'django.db.backends.postgresql_psycopg2' isn't an available database backend. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Try using django.db.backends.XXX, where XXX is one of: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] 'dummy', 'mysql', 'oracle', 'postgresql', 'postgresql_psycopg2', 'sqlite3' [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Error was: cannot import name utils please help me!!

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