Date: Sat, 5 Mar 2005 18:50:12 -0800 (PST) From: =?ISO-8859-1?Q?Mikko_Ty=F6l=E4j=E4rvi?= <mbsd@pacbell.net> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/78478: Writing to closed socket does not generate SIGPIPE Message-ID: <20050305184839.N693@antec.home> Resent-Message-ID: <200503060250.j262oHSg075539@freefall.freebsd.org>
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>Number: 78478 >Category: kern >Synopsis: writing to closed socket does not generate SIGPIPE >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Mar 06 02:50:17 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Mikko Tyolajarvi >Release: FreeBSD 6.0-CURRENT i386 >Organization: >Environment: System: FreeBSD sotec.home 6.0-CURRENT FreeBSD 6.0-CURRENT #28: Sat Mar 5 16:58:15 PST 2005 mikko@sotec.home:/usr/obj/usr/src/sys/SOTEC i386 5.3-RELEASE, 5-STABLE, 6-CURRENT all behave the same. >Description: Using write(2) to write to a connected socket, IP or unix domain, where the other end has closed the connection should result in a SIGPIPE signal being generated, and does so on FreeBSD 4.11 (as well as Solaris 2.6, 8 & 10, HPUX 11.00 & 11.22, Linux 2.4 & 2.6 etc). Using send(2) instead of write(2) does produce the signal, as does write(2) to a pipe. It is only the combination of write(2) and a stream socket that does not work. >How-To-Repeat: #include <sys/types.h> #include <sys/socket.h> #include <sys/time.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <arpa/inet.h> #include <errno.h> #include <unistd.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> static void gotpipe(int sig) { printf("SIGPIPE\n"); exit(0); } int main(int argc, char *argv[]) { char data[32 * 1024]; int sock, lsock, asock; socklen_t len; int i, use_send, set_nosigpipe; struct sockaddr_in ia; use_send = (argc > 1 && strchr(argv[1], 's')); set_nosigpipe = (argc > 1 && strchr(argv[1], 'n')); signal(SIGPIPE, gotpipe); lsock = socket(AF_INET, SOCK_STREAM, 0); memset(&ia, 0, sizeof(ia)); ia.sin_addr.s_addr = htonl(INADDR_LOOPBACK); bind(lsock, (struct sockaddr *)&ia, sizeof(ia)); listen(lsock, 5); len = sizeof(ia); if (getsockname(lsock, (struct sockaddr *)&ia, &len) < 0) { perror("getsockname"); return 1; } sock = socket(AF_INET, SOCK_STREAM, 0); if (connect(sock, (struct sockaddr *)&ia, sizeof(ia)) < 0) { perror("connect"); return 1; } asock = accept(lsock, NULL, NULL); close(lsock); close(asock); #ifdef SO_NOSIGPIPE if (set_nosigpipe) { i = 1; if (setsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, &i, sizeof(i)) < 0) { perror("setsockopt"); } } len = sizeof(i); if (getsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, &i, &len) < 0) { perror("getsockopt"); return 1; } printf("SO_NOSIGPIPE is %d\n", i); #else printf("SO_NOSIGPIPE not supported\n"); #endif for (i = 0; i < 4; i++) { if (use_send) { if (send(sock, data, sizeof(data), 0) < 0) { perror("send"); } } else { if (write(sock, data, sizeof(data)) < 0) { perror("write"); } } } printf("No sigpipe\n"); return 1; } >Fix: This seems to be one way to solve the problem: Index: sys_socket.c =================================================================== RCS file: /home/ncvs/src/sys/kern/sys_socket.c,v retrieving revision 1.67 diff -b -u -r1.67 sys_socket.c --- sys_socket.c 6 Jan 2005 23:35:39 -0000 1.67 +++ sys_socket.c 6 Mar 2005 02:44:58 -0000 @@ -39,8 +39,11 @@ #include <sys/file.h> #include <sys/filedesc.h> #include <sys/mac.h> +#include <sys/proc.h> #include <sys/protosw.h> #include <sys/sigio.h> +#include <sys/signal.h> +#include <sys/signalvar.h> #include <sys/socket.h> #include <sys/socketvar.h> #include <sys/filio.h> /* XXX */ @@ -115,6 +118,13 @@ error = so->so_proto->pr_usrreqs->pru_sosend(so, 0, uio, 0, 0, 0, uio->uio_td); NET_UNLOCK_GIANT(); + + /* Generation of SIGPIPE can be controlled per socket */ + if (error == EPIPE && !(so->so_options & SO_NOSIGPIPE)) { + PROC_LOCK(td->td_proc); + psignal(td->td_proc, SIGPIPE); + PROC_UNLOCK(td->td_proc); + } return (error); } >Release-Note: >Audit-Trail: >Unformatted:
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