Date: Wed, 22 Apr 2020 17:32:21 +0000 From: bugzilla-noreply@freebsd.org To: doc@FreeBSD.org Subject: [Bug 245817] sendto() can return ENOTCONN on SOCK_STREAM unix socket, which is not documented Message-ID: <bug-245817-9-zRZizdWGdg@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-245817-9@https.bugs.freebsd.org/bugzilla/> References: <bug-245817-9@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=245817 --- Comment #2 from Mark Johnston <markj@FreeBSD.org> --- I see. The SOCK_STREAM/SEQPACKET unix socket protocol descriptions set PR_CONNREQUIRED, which effectively disables sendto()/sendmsg() on unconnected unix sockets. That is surprising since uipc_send() has explicit handling for that: 1137 case SOCK_SEQPACKET: 1138 case SOCK_STREAM: 1139 if ((so->so_state & SS_ISCONNECTED) == 0) { 1140 if (nam != NULL) { 1141 error = connect_internal(so, nam, td); 1142 if (error != 0) 1143 break; 1144 } else { 1145 error = ENOTCONN; 1146 break; 1147 } 1148 } else { 1149 UNP_PCB_LOCK(unp); 1150 } I think we can probably just clear PR_CONNREQUIRED for unix sockets. Though, I think we should indeed document ENOTCONN as a possible error for sendto() and sendmsg(). It is documented here for instance: https://pubs.opengroup.org/onlinepubs/009695399/functions/sendto.html Also weird is this fragment in sosend_generic(): 1626 /* 1627 * `sendto' and `sendmsg' is allowed on a connection- 1628 * based socket if it supports implied connect. 1629 * Return ENOTCONN if not connected and no address is 1630 * supplied. 1631 */ 1632 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) && 1633 (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) { 1634 if ((so->so_state & SS_ISCONFIRMING) == 0 && 1635 !(resid == 0 && clen != 0)) { 1636 SOCKBUF_UNLOCK(&so->so_snd); 1637 error = ENOTCONN; 1638 goto release; 1639 } Specifically, the !(resid == 0 && clen != 0) check: we only return an error if we are trying to send data and there is no control message. So, we *can* send control messages over unconnected stream sockets even if CONNREQUIRED is set. Does any protocol except PF_LOCAL handle control messages to begin with? -- You are receiving this mail because: You are on the CC list for the bug.help
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