rework sosend: no EWOULDBLOCK after partial write; allow zero-length

datagrams; eliminate goto's and untwist loop; simplify space calculation
(still wrong, but won't send partial datagrams!)

SCCS-vsn: sys/kern/uipc_socket.c 6.3

diff --git a/usr/src/sys/kern/uipc_socket.c b/usr/src/sys/kern/uipc_socket.c
index ea5bf11..17a669a 100644 (file)
--- a/usr/src/sys/kern/uipc_socket.c
+++ b/usr/src/sys/kern/uipc_socket.c
@@ -1,4 +1,4 @@
-/*     uipc_socket.c   6.2     83/09/29        */
+/*     uipc_socket.c   6.3     84/04/24        */

 
 #include "../h/param.h"
 #include "../h/systm.h"
 
 #include "../h/param.h"
 #include "../h/systm.h"


@@ -268,6 +268,7 @@ bad:
  * Lock against other senders.
  * If must go all at once and not enough room now, then
  * inform user that this would block and do nothing.
  * Lock against other senders.
  * If must go all at once and not enough room now, then
  * inform user that this would block and do nothing.

+ * Otherwise, if nonblocking, send as much as possible.

  */
 sosend(so, nam, uio, flags, rights)
        register struct socket *so;
  */
 sosend(so, nam, uio, flags, rights)
        register struct socket *so;


@@ -277,40 +278,92 @@ sosend(so, nam, uio, flags, rights)
        struct mbuf *rights;
 {
        struct mbuf *top = 0;
        struct mbuf *rights;
 {
        struct mbuf *top = 0;

-       register struct mbuf *m, **mp = ⊤
+       register struct mbuf *m, **mp;

        register int space;
        register int space;

-       int len, error = 0, s, dontroute;
-       struct sockbuf sendtempbuf;
+       int len, error = 0, s, dontroute, first = 1;

 
        if (sosendallatonce(so) && uio->uio_resid > so->so_snd.sb_hiwat)
                return (EMSGSIZE);
        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
            (so->so_proto->pr_flags & PR_ATOMIC);
 
        if (sosendallatonce(so) && uio->uio_resid > so->so_snd.sb_hiwat)
                return (EMSGSIZE);
        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
            (so->so_proto->pr_flags & PR_ATOMIC);

-restart:
-       sblock(&so->so_snd);
+       u.u_ru.ru_msgsnd++;

 #define        snderr(errno)   { error = errno; splx(s); goto release; }
 
 #define        snderr(errno)   { error = errno; splx(s); goto release; }
 

-       u.u_ru.ru_msgsnd++;
-again:
-       s = splnet();
-       if (so->so_state & SS_CANTSENDMORE) {
-               psignal(u.u_procp, SIGPIPE);
-               snderr(EPIPE);
-       }
-       if (so->so_error) {
-               error = so->so_error;
-               so->so_error = 0;                               /* ??? */
+restart:
+       sblock(&so->so_snd);
+       do {
+               s = splnet();
+               if (so->so_state & SS_CANTSENDMORE) {
+                       psignal(u.u_procp, SIGPIPE);
+                       snderr(EPIPE);
+               }
+               if (so->so_error) {
+                       error = so->so_error;
+                       so->so_error = 0;                       /* ??? */
+                       splx(s);
+                       goto release;
+               }
+               if ((so->so_state & SS_ISCONNECTED) == 0) {
+                       if (so->so_proto->pr_flags & PR_CONNREQUIRED)
+                               snderr(ENOTCONN);
+                       if (nam == 0)
+                               snderr(EDESTADDRREQ);
+               }
+               if (flags & MSG_OOB)
+                       space = 1024;
+               else {
+                       space = sbspace(&so->so_snd);
+                       if (space <= 0 ||
+                           sosendallatonce(so) && space < uio->uio_resid) {
+                               if (so->so_state & SS_NBIO) {
+                                       if (first)
+                                               error = EWOULDBLOCK;
+                                       splx(s);
+                                       goto release;
+                               }
+                               sbunlock(&so->so_snd);
+                               sbwait(&so->so_snd);
+                               splx(s);
+                               goto restart;
+                       }
+               }

                splx(s);
                splx(s);

-               goto release;
-       }
-       if ((so->so_state & SS_ISCONNECTED) == 0) {
-               if (so->so_proto->pr_flags & PR_CONNREQUIRED)
-                       snderr(ENOTCONN);
-               if (nam == 0)
-                       snderr(EDESTADDRREQ);
-       }
-       if (top) {
+               mp = &top;
+               while (uio->uio_resid > 0 && space > 0) {
+                       register struct iovec *iov = uio->uio_iov;
+
+                       if (iov->iov_len == 0) {
+                               uio->uio_iov++;
+                               uio->uio_iovcnt--;
+                               if (uio->uio_iovcnt < 0)
+                                       panic("sosend");
+                               continue;
+                       }
+                       MGET(m, M_WAIT, MT_DATA);
+                       if (m == NULL) {
+                               error = ENOBUFS;                /* SIGPIPE? */
+                               goto release;
+                       }
+                       if (iov->iov_len >= CLBYTES && space >= CLBYTES) {
+                               register struct mbuf *p;
+                               MCLGET(p, 1);
+                               if (p == 0)
+                                       goto nopages;
+                               m->m_off = (int)p - (int)m;
+                               len = CLBYTES;
+                       } else {
+nopages:
+                               len = MIN(MLEN, iov->iov_len);
+                       }
+                       error = uiomove(mtod(m, caddr_t), len, UIO_WRITE, uio);
+                       m->m_len = len;
+                       *mp = m;
+                       if (error)
+                               goto release;
+                       mp = &m->m_next;
+                       space -= len;
+               }

                if (dontroute)
                        so->so_options |= SO_DONTROUTE;
                error = (*so->so_proto->pr_usrreq)(so,
                if (dontroute)
                        so->so_options |= SO_DONTROUTE;
                error = (*so->so_proto->pr_usrreq)(so,


@@ -319,77 +372,10 @@ again:
                if (dontroute)
                        so->so_options &= ~SO_DONTROUTE;
                top = 0;
                if (dontroute)
                        so->so_options &= ~SO_DONTROUTE;
                top = 0;

-               if (error) {
-                       splx(s);
-                       goto release;
-               }
-               mp = &top;
-       }
-       if (uio->uio_resid == 0) {
-               splx(s);
-               goto release;
-       }
-       if (flags & MSG_OOB)
-               space = 1024;
-       else {
-               space = sbspace(&so->so_snd);
-               if (space <= 0 ||
-                   sosendallatonce(so) && space < uio->uio_resid) {
-                       if (so->so_state & SS_NBIO)
-                               snderr(EWOULDBLOCK);
-                       sbunlock(&so->so_snd);
-                       sbwait(&so->so_snd);
-                       splx(s);
-                       goto restart;
-               }
-       }
-       splx(s);
-       /*
-        * Temporary kludge-- don't want to update so_snd in this loop
-        * (will be done when sent), but need to recalculate
-        * space on each iteration.  For now, copy so_snd into a tmp.
-        */
-       sendtempbuf = so->so_snd;
-       while (uio->uio_resid > 0 && space > 0) {
-               register struct iovec *iov = uio->uio_iov;
-
-               if (iov->iov_len == 0) {
-                       uio->uio_iov++;
-                       uio->uio_iovcnt--;
-                       if (uio->uio_iovcnt < 0)
-                               panic("sosend");
-                       continue;
-               }
-               MGET(m, M_WAIT, MT_DATA);
-               if (m == NULL) {
-                       error = ENOBUFS;                        /* SIGPIPE? */
-                       goto release;
-               }
-               if (iov->iov_len >= CLBYTES && space >= CLBYTES) {
-                       register struct mbuf *p;
-                       MCLGET(p, 1);
-                       if (p == 0)
-                               goto nopages;
-                       m->m_off = (int)p - (int)m;
-                       len = CLBYTES;
-               } else {
-nopages:
-                       len = MIN(MLEN, iov->iov_len);
-               }
-               error = uiomove(mtod(m, caddr_t), len, UIO_WRITE, uio);
-               m->m_len = len;
-               *mp = m;
+               first = 0;

                if (error)
                if (error)

-                       goto release;
-               mp = &m->m_next;
-               if (flags & MSG_OOB)
-                       space -= len;
-               else {
-                       sballoc(&sendtempbuf, m);
-                       space = sbspace(&sendtempbuf);
-               }
-       }
-       goto again;
+                       break;
+       } while (uio->uio_resid);

 
 release:
        sbunlock(&so->so_snd);
 
 release:
        sbunlock(&so->so_snd);