Error Reading From Socket Interrupted System Call
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Snmpd Read Interrupted System Call
Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million waitpid error interrupted system call programmers, just like you, helping each other. Join them; it only takes a minute: Sign up c / interrupted system call / fork vs. thread up vote 4 down vote favorite 1 I discovered an issue with
Interrupted System Call Linux
thread implementation, that is strange to me. Maybe some of you can explain it to me, would be great. I am working on something like a proxy, a program (running on different machines) that receives packets over eth0 and sends it through ath0 (wireless) to another machine which is doing the exactly same thing. Actually I am not at all sure what is causing my problem, that's because I am new to everything, linux interrupted system call in unix and c programming. I start two threads, one is listening (socket) on eth0 for incoming packets and sends it out through ath0 (also socket) and the other thread is listening on ath0 and sends through eth0. If I use threads, I get an error like that: sh-2.05b# ./socketex Failed to send network header packet. : Interrupted system call If I use fork(), the program works as expected. Can someone explain that behaviour to me? Just to show the sender implementation here comes its code snippet: while(keep_going) { memset(&buffer[0], '\0', sizeof(buffer)); recvlen = recvfrom(sockfd_in, buffer, BUFLEN, 0, (struct sockaddr *) &incoming, &ilen); if(recvlen < 0) { perror("something went wrong / incoming\n"); exit(-1); } strcpy(msg, buffer); buflen = strlen(msg); sentlen = ath_sendto(sfd, &btpinfo, &addrnwh, &nwh, buflen, msg, &selpv2, &depv); if(sentlen == E_ERR) { perror("Failed to send network header packet.\n"); exit(-1); } } UPDATE: my main file, starting either threads or processes (fork) int main(void) { port_config pConfig; memset(&pConfig, 0, sizeof(pConfig)); pConfig.inPort = 2002; pConfig.outPort = 2003; pid_t retval = fork(); if(retval == 0) { // child process pc2wsuThread((void *) &pConfig); } else if (retval < 0) { perror("fork not successful\n"); } else { // parent process wsu2pcThread((void *) &pConfig); } /* wint8 rc1, rc2 = 0; pthread_t pc2wsu; pthread_t wsu2pc; rc1 = pthread_create(&pc2wsu, NULL, pc2wsuThread, (void *) &pConfig); rc2 = pthread
point about the behavior of the Unix (socket API) connect() system call when it is interrupted by a signal. It points out how obscure the Single Unix Specification is, and notes that many existing Unix implementations seem to have f*cked this up somehow. The
Interrupted System Call Errno
question is this: if a blocking connect() (on a blocking stream socket, that is) is
Interrupted System Call Recv
interrupted by a signal, returning EINTR, in what state is the socket left, and is it permissible to restart the system call? interrupted system call c What happens if a second connect() with the same arguments is attempted immediately after one failed with EINTR? The reference for connect() (hereafter, “the Spec”) is part of the Open Group's Single Unix Specification, version3 (note: you may http://stackoverflow.com/questions/6030310/c-interrupted-system-call-fork-vs-thread need to register to read this; see also here). Here is the relevant part of it: If the initiating socket is connection-mode, then connect() shall attempt to establish a connection to the address specified by the address argument. If the connection cannot be established immediately and O_NONBLOCK is not set for the file descriptor for the socket, connect() shall block for up to an unspecified timeout interval until the connection is established. If the timeout http://www.madore.org/~david/computers/connect-intr.html interval expires before the connection is established, connect() shall fail and the connection attempt shall be aborted. If connect() is interrupted by a signal that is caught while blocked waiting to establish a connection, connect() shall fail and set connect() to [EINTR], but the connection request shall not be aborted, and the connection shall be established asynchronously. If the connection cannot be established immediately and O_NONBLOCK is set for the file descriptor for the socket, connect() shall fail and set errno to [EINPROGRESS], but the connection request shall not be aborted, and the connection shall be established asynchronously. Subsequent calls to connect() for the same socket, before the connection is established, shall fail and set errno to [EALREADY]. When the connection has been established asynchronously, select() and poll() shall indicate that the file descriptor for the socket is ready for writing. Later on, when listing possible error codes for connect(), the Spec mentions: The connect() function shall fail if: […] [EALREADY] A connection request is already in progress for the specified socket. How does this answer the question above? That is, what is supposed to happen, according to the Spec, when a second connect() is attempted (with the same arguments) just after one which returned EINTR (on a blocking stream socket)? To me it seems that the Spec is contradictory. On the o
socket - UNIX Programming Hello, I have a server application and a client one which communicate with sockets and SSH tunneling (ssh -N -f -L8888:localhost:3333 userlocalhost). I have to use ssh tunneling because of firewalls. My problem is that the read in the client has http://www.justskins.com/forums/interrupted-system-call-read-235357.html the "Interrupted system call" error even if I put this while(-1==(nr=read(DIST,ptr,nl))) { if(errno!=EINTR) break; } and it appears randomly. If I do not use ssh tunneling, it works. If someone has an idea ... Thanks, Karim.... Thread Tools Show Printable Version Email this Page… Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode January 9th,07:19 PM #1 "Interrupted system call", read and socket Hello, I have a server application and a interrupted system client one which communicate with sockets and SSH tunneling (ssh -N -f -L8888:localhost:3333 userlocalhost). I have to use ssh tunneling because of firewalls. My problem is that the read in the client has the "Interrupted system call" error even if I put this while(-1==(nr=read(DIST,ptr,nl))) { if(errno!=EINTR) break; } and it appears randomly. If I do not use ssh tunneling, it works. If someone has an idea ... Thanks, Karim. karim Guest January 10th,09:29 AM #2 Re: "Interrupted system interrupted system call call", read and socket karim bernardet wrote: No idea. Typically, you will receive this error when the syscall blocks and a signal is delivered. However why bother, just resume read(). E.g.: int readn(int fd, void* data, size_t size) { for (;;) { ssize_t n = read(fd, data, size); if (n == -1) { if (errno == EINTR) continue; // Resume. return errno; } if (!(size -= n)) return 0; data = (char*)data + n; } } /FAU Frank Guest January 11th,03:22 PM #3 Re: "Interrupted system call", read and socket Hello Karim, [/ref] So basically, you resume the read() and you still get an "Interrupted system call"? Whether your loop construct is wrong (doesn't look like to me. Though I prefer Frank's construct which is somewhat nicier to read)... Or it's not the read() call that got interrupted... Regards, Loic. Loic Guest « Help: how to change indent character in VI? | Finding Skeleton Daemon Code » Similar Threads How to call the operation-system "Save As" DialogueBox By fighttodeath in forum Macromedia Flex General Discussion Replies: 7 Last Post: June 2nd, 07:35 PM CALL TO ACTION: Photoshop GURU's help solve "BULGEGATE"... please read By political commentator in forum Adobe Flash, Flex & Director Replies: 4 Last Post: October 29th, 01:10 AM Help with "A specified file does not support the ioctl system call." in cron By Todd H. in forum