Fixed sys_socket() plumbing

[Martin Pieuchot]

I found my mistake in the previous diff.  `SS_NBIO' was never set on
non blocking sockets.  Diff below fixes that by checking `nonblock'
like it is done in sys_socketpair().

Tests & oks welcome :)

Index: kern/uipc_syscalls.c
===================================================================
RCS file: /cvs/src/sys/kern/uipc_syscalls.c,v
retrieving revision 1.164
diff -u -p -r1.164 uipc_syscalls.c
--- kern/uipc_syscalls.c        11 Feb 2018 21:53:57 -0000      1.164
+++ kern/uipc_syscalls.c        12 Feb 2018 08:19:30 -0000
@@ -83,7 +83,7 @@ sys_socket(struct proc *p, void *v, regi
        struct file *fp;
        int type = SCARG(uap, type);
        int domain = SCARG(uap, domain);
-       int fd, error;
+       int fd, cloexec, nonblock, fflag, error;
        unsigned int ss = 0;
 
        if ((type & SOCK_DNS) && !(domain == AF_INET || domain == AF_INET6))
@@ -95,24 +95,25 @@ sys_socket(struct proc *p, void *v, regi
        if (error)
                return (error);
 
-       fdplock(fdp);
-       error = falloc(p, (type & SOCK_CLOEXEC) ? UF_EXCLOSE : 0, &fp, &fd);
-       fdpunlock(fdp);
+       type &= ~(SOCK_CLOEXEC | SOCK_NONBLOCK | SOCK_DNS);
+       cloexec = (SCARG(uap, type) & SOCK_CLOEXEC) ? UF_EXCLOSE : 0;
+       nonblock = SCARG(uap, type) & SOCK_NONBLOCK;
+       fflag = FREAD | FWRITE | (nonblock ? FNONBLOCK : 0);
+
+       error = socreate(SCARG(uap, domain), &so, type, SCARG(uap, protocol));
        if (error != 0)
                goto out;
 
-       fp->f_flag = FREAD | FWRITE | (type & SOCK_NONBLOCK ? FNONBLOCK : 0);
-       fp->f_type = DTYPE_SOCKET;
-       fp->f_ops = &socketops;
-       error = socreate(SCARG(uap, domain), &so,
-           type & ~(SOCK_CLOEXEC | SOCK_NONBLOCK | SOCK_DNS), SCARG(uap, 
protocol));
+       fdplock(fdp);
+       error = falloc(p, cloexec, &fp, &fd);
+       fdpunlock(fdp);
        if (error) {
-               fdplock(fdp);
-               fdremove(fdp, fd);
-               closef(fp, p);
-               fdpunlock(fdp);
+               soclose(so);
        } else {
-               if (type & SOCK_NONBLOCK)
+               fp->f_flag = fflag;
+               fp->f_type = DTYPE_SOCKET;
+               fp->f_ops = &socketops;
+               if (nonblock)
                        so->so_state |= SS_NBIO;
                so->so_state |= ss;
                fp->f_data = so;
@@ -451,7 +452,7 @@ sys_socketpair(struct proc *p, void *v, 
 
        type  = SCARG(uap, type) & ~(SOCK_CLOEXEC | SOCK_NONBLOCK);
        cloexec = (SCARG(uap, type) & SOCK_CLOEXEC) ? UF_EXCLOSE : 0;
-       nonblock = SCARG(uap, type) &  SOCK_NONBLOCK;
+       nonblock = SCARG(uap, type) & SOCK_NONBLOCK;
        fflag = FREAD | FWRITE | (nonblock ? FNONBLOCK : 0);
 
        error = socreate(SCARG(uap, domain), &so1, type, SCARG(uap, protocol));