Date: Sat, 8 Apr 2000 10:31:35 -0700 From: Alfred Perlstein <bright@wintelcom.net> To: Sean Peck <speck@news1.newsindex.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD 3.3 fork/Exec bug? Message-ID: <20000408103135.Z4381@fw.wintelcom.net> In-Reply-To: <Pine.BSI.3.95.1000408122156.882A-100000@news1.newsindex.com>; from speck@news1.newsindex.com on Sat, Apr 08, 2000 at 12:38:20PM -0400 References: <20000408084711.W4381@fw.wintelcom.net> <Pine.BSI.3.95.1000408122156.882A-100000@news1.newsindex.com>
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* Sean Peck <speck@news1.newsindex.com> [000408 09:47] wrote:
> Alfred,
>
> Here is the code being used.
ew. :P There seems to be some problems in your tcp connect library...
> while((result !=1)&&(result!=TCP_CONNECT_NONE)&&(timeout!=10)){
> result = tcp_get_conn(localhostname,port1,10,&sock1);
> if(result==TCP_CONNECT_TIMEOUT){timeout++;}
> }
> printf("result %d\n",result); //This is coming back 1 in both the
> // fork/execlp and in direct from shell
> // running
> printf("ERRNO %d\n",errno); // this is coming back 36 in both shell and
> // fork/execlp
36 is EINPROGRESS, somehow your connect function isn't handling non-blocking
connects properly.
> Here is the tcp_get_connection() code
>
> /*
> * given a HOST name and service PORT number, return connected TCP
> * socket to the requested service at the requested host. It will
> * timeout after SECS (if < 0 then hang). Passes back socket in SOCKP
> * and returns error codes.
> */
>
> /* tcp_get_conn return codes */
> #define TCP_NO_ERROR 1 /* no error */
> #define TCP_NOT_FOUND 2 /* host not found */
> #define TCP_SOCKET_FAILURE 3 /* socket create failure
> */
> #define TCP_CONNECT_ERROR 4 /* socket connect error */
> #define TCP_CONNECT_TIMEOUT 5 /* socket connect timeout
> */
> #define TCP_CONNECT_NONE 6 /* socket didn't connect
> */
> #define TCP_TRANSFER_ERROR 7 /* read/write error */
>
> EXPORT int tcp_get_conn(const char * host, const int port,
> const int secs, int * sockp)
> {
> struct sockaddr_in sadr;
> struct hostent *hostp;
> struct timeval timeout, *timeoutp;
> fd_set fds;
> char **addrp, okay = 0;
> int sock, ret;
> #ifdef __osf__
> struct itimerval timer;
> #endif
>
> /* locate host */
> hostp = gethostbyname(host);
> if (hostp == NULL)
> return TCP_NOT_FOUND;
>
> /* setup internet port */
> sadr.sin_family = (u_short)AF_INET;
> sadr.sin_port = htons(port);
>
> sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
> if (sock < 0)
> return TCP_SOCKET_FAILURE;
>
> #ifndef __osf__
> /* make the fd non-blocking */
> (void)fcntl(sock, F_SETFL, fcntl(sock, F_GETFL, 0) | O_NONBLOCK);
> #endif
>
> if (secs < 0)
> timeoutp = 0L;
> else
> timeoutp = &timeout;
> FD_ZERO(&fds);
>
> /* try to connect to the remote server */
> for (addrp = hostp->h_addr_list; *addrp != NULL; addrp++) {
> (void)memcpy((void *)&sadr.sin_addr, *addrp, sizeof(sadr.sin_addr));
>
> #ifdef __osf__
> /* set the timer */
> timer.it_interval = timeout;
> setitimer(ITIMER_REAL, &timer, NULL);
> (void)signal(SIGALRM, catch_alarm);
> alarm_caught = FALSE;
> #endif
>
> /* connect or start the connection */
> ret = connect(sock, (void *)&sadr, sizeof(sadr));
>
> #ifdef __osf__
> /* disable the timer */
> timer.it_value.tv_sec = 0;
> timer.it_value.tv_usec = 0;
> setitimer(ITIMER_REAL, &timer, NULL);
> (void)signal(SIGALRM, SIG_IGN);
> #endif
>
> if (ret == 0) {
> okay = 1;
> break;
> }
>
> #ifdef __osf__
> (void)close(sock);
>
> if (alarm_caught)
> return TCP_CONNECT_TIMEOUT;
> else
> return TCP_CONNECT_ERROR;
> #endif
>
> /* not waiting for connection? */
>
> if (errno != EINPROGRESS && errno != EWOULDBLOCK) {
> /* connection refused? */
>
> if (errno == ECONNREFUSED)
> continue;
>
> /* otherwise error */
> (void)close(sock);
> return TCP_CONNECT_ERROR;
> }
>
> for (;;) {
FD_ZERO here?
> FD_SET(sock, &fds);
> if (secs >= 0) {
> timeout.tv_sec = secs;
> timeout.tv_usec = 0;
> }
>
> ret = select(sock + 1, 0L, &fds, 0L, timeoutp);
0L -> NULL please :)
> if (ret > 0 && FD_ISSET(sock, &fds)) {
> okay = 1;
> break;
> }
> if (ret == 0) {
> (void)close(sock);
> return TCP_CONNECT_TIMEOUT;
> }
> if (ret < 0 && errno != EINTR) {
> (void)close(sock);
> return TCP_CONNECT_ERROR;
> }
> }
>
> if (okay)
> break;
> }
>
> /* connection made? */
> if (okay) {
> #ifndef __osf__
> /* turn off non-blocking */
> (void)fcntl(sock, F_SETFL, fcntl(sock, F_GETFL, 0) & ~O_NONBLOCK);
> #endif
> *sockp = sock;
> return TCP_NO_ERROR;
> }
>
> (void)close(sock);
> return TCP_CONNECT_NONE;
> }
>
Pick up a copy of Unix Netork Programming vol I, see page 411, it
has a very good example on how to do non-blocking connects properly.
--
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."
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