Annotation of 43BSD/old/talk/ctl_transact.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1983 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #ifndef lint
        !             8: static char sccsid[] = "@(#)ctl_transact.c     5.1 (Berkeley) 6/6/85";
        !             9: #endif not lint
        !            10: 
        !            11: #include "talk_ctl.h"
        !            12: #include <sys/time.h>
        !            13: 
        !            14: #define CTL_WAIT 2     /* time to wait for a response, in seconds */
        !            15: 
        !            16: /*
        !            17:  * SOCKDGRAM is unreliable, so we must repeat messages if we have
        !            18:  * not recieved an acknowledgement within a reasonable amount
        !            19:  * of time
        !            20:  */
        !            21: ctl_transact(target, msg, type, response)
        !            22:        struct in_addr target;
        !            23:        CTL_MSG msg;
        !            24:        int type;
        !            25:        CTL_RESPONSE *response;
        !            26: {
        !            27:        struct sockaddr junk;
        !            28:        int read_mask;
        !            29:        int ctl_mask;
        !            30:        int nready;
        !            31:        int cc;
        !            32:        int junk_size;
        !            33:        struct timeval wait;
        !            34: 
        !            35:        msg.type = type;
        !            36:        daemon_addr.sin_addr = target;
        !            37:        daemon_addr.sin_port = daemon_port;
        !            38:        ctl_mask = 1 << ctl_sockt;
        !            39: 
        !            40:        /*
        !            41:         * keep sending the message until a response of the right
        !            42:         * type is obtained
        !            43:         */
        !            44:        do {
        !            45:                wait.tv_sec = CTL_WAIT;
        !            46:                wait.tv_usec = 0;
        !            47: 
        !            48:                /* keep sending the message until a response is obtained */
        !            49:                do {
        !            50:                        cc = sendto(ctl_sockt, (char *)&msg, sizeof(CTL_MSG), 0,
        !            51:                                &daemon_addr, sizeof(daemon_addr));
        !            52:                        if (cc != sizeof(CTL_MSG)) {
        !            53:                                if (errno == EINTR)
        !            54:                                        continue;
        !            55:                                p_error("Error on write to talk daemon");
        !            56:                        }
        !            57:                        read_mask = ctl_mask;
        !            58:                        if ((nready = select(32, &read_mask, 0, 0, &wait)) < 0) {
        !            59:                                if (errno == EINTR)
        !            60:                                        continue;
        !            61:                                p_error("Error waiting for daemon response");
        !            62:                        }
        !            63:                } while (nready == 0);
        !            64:                /* keep reading while there are queued messages 
        !            65:                   (this is not necessary, it just saves extra
        !            66:                   request/acknowledgements being sent)
        !            67:                 */
        !            68:                do {
        !            69:                        junk_size = sizeof(junk);
        !            70:                        cc = recvfrom(ctl_sockt, (char *)response,
        !            71:                            sizeof (CTL_RESPONSE), 0, &junk, &junk_size);
        !            72:                        if (cc < 0) {
        !            73:                                if (errno == EINTR)
        !            74:                                        continue;
        !            75:                                p_error("Error on read from talk daemon");
        !            76:                        }
        !            77:                        read_mask = ctl_mask;
        !            78:                        /* an immediate poll */
        !            79:                        timerclear(&wait);
        !            80:                        nready = select(32, &read_mask, 0, 0, &wait);
        !            81:                } while (nready > 0 && response->type != type);
        !            82:        } while (response->type != type);
        !            83: }

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