[Qemu-devel] [PATCH v6 1/5] sockets: change inet_connect() to support nonblock socket

[Amos Kong]

Add a bool argument to inet_connect() to assign if set socket
to block/nonblock, and delete original argument 'socktype'
that is unused.

Retry to connect when following errors are got:
  -EINTR
  -EWOULDBLOCK (win32)
Connect's successful for nonblock socket when following
errors are got, user should wait for connecting by select():
  -EINPROGRESS
  -WSAEALREADY (win32)

Change nbd, vnc to use new interface.

Signed-off-by: Amos Kong <address@hidden>
---
 nbd.c          |    2 +-
 qemu-sockets.c |   58 +++++++++++++++++++++++++++++++++++++++++++-------------
 qemu_socket.h  |    2 +-
 ui/vnc.c       |    2 +-
 4 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/nbd.c b/nbd.c
index 406e555..b4e68a9 100644
--- a/nbd.c
+++ b/nbd.c
@@ -146,7 +146,7 @@ int tcp_socket_outgoing(const char *address, uint16_t port)
 
 int tcp_socket_outgoing_spec(const char *address_and_port)
 {
-    return inet_connect(address_and_port, SOCK_STREAM);
+    return inet_connect(address_and_port, true);
 }
 
 int tcp_socket_incoming(const char *address, uint16_t port)
diff --git a/qemu-sockets.c b/qemu-sockets.c
index 6bcb8e3..e886195 100644
--- a/qemu-sockets.c
+++ b/qemu-sockets.c
@@ -51,6 +51,9 @@ static QemuOptsList dummy_opts = {
         },{
             .name = "ipv6",
             .type = QEMU_OPT_BOOL,
+        },{
+            .name = "block",
+            .type = QEMU_OPT_BOOL,
         },
         { /* end if list */ }
     },
@@ -201,7 +204,8 @@ int inet_connect_opts(QemuOpts *opts)
     const char *port;
     char uaddr[INET6_ADDRSTRLEN+1];
     char uport[33];
-    int sock,rc;
+    int sock, rc, err;
+    bool block;
 
     memset(&ai,0, sizeof(ai));
     ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
@@ -210,6 +214,7 @@ int inet_connect_opts(QemuOpts *opts)
 
     addr = qemu_opt_get(opts, "host");
     port = qemu_opt_get(opts, "port");
+    block = qemu_opt_get_bool(opts, "block", 0);
     if (addr == NULL || port == NULL) {
         fprintf(stderr, "inet_connect: host and/or port not specified\n");
         return -1;
@@ -241,21 +246,44 @@ int inet_connect_opts(QemuOpts *opts)
             continue;
         }
         setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(void*)&on,sizeof(on));
-
+        if (!block) {
+            socket_set_nonblock(sock);
+        }
         /* connect to peer */
-        if (connect(sock,e->ai_addr,e->ai_addrlen) < 0) {
-            if (NULL == e->ai_next)
-                fprintf(stderr, "%s: connect(%s,%s,%s,%s): %s\n", __FUNCTION__,
-                        inet_strfamily(e->ai_family),
-                        e->ai_canonname, uaddr, uport, strerror(errno));
-            closesocket(sock);
-            continue;
+        do {
+            err = 0;
+            if (connect(sock, e->ai_addr, e->ai_addrlen) < 0) {
+                err = -socket_error();
+            }
+#ifndef _WIN32
+        } while (err == -EINTR || err == -EWOULDBLOCK);
+#else
+        } while (err == -EINTR);
+#endif
+
+        if (err >= 0) {
+            goto success;
+        } else if (!block && err == -EINPROGRESS) {
+            goto success;
+#ifdef _WIN32
+        } else if (!block && err == -WSAEALREADY) {
+            goto success;
+#endif
         }
-        freeaddrinfo(res);
-        return sock;
+
+        if (NULL == e->ai_next) {
+            fprintf(stderr, "%s: connect(%s,%s,%s,%s): %s\n", __FUNCTION__,
+                    inet_strfamily(e->ai_family),
+                    e->ai_canonname, uaddr, uport, strerror(errno));
+        }
+        closesocket(sock);
     }
     freeaddrinfo(res);
     return -1;
+
+success:
+    freeaddrinfo(res);
+    return sock;
 }
 
 int inet_dgram_opts(QemuOpts *opts)
@@ -449,14 +477,18 @@ int inet_listen(const char *str, char *ostr, int olen,
     return sock;
 }
 
-int inet_connect(const char *str, int socktype)
+int inet_connect(const char *str, bool block)
 {
     QemuOpts *opts;
     int sock = -1;
 
     opts = qemu_opts_create(&dummy_opts, NULL, 0);
-    if (inet_parse(opts, str) == 0)
+    if (inet_parse(opts, str) == 0) {
+        if (block) {
+            qemu_opt_set(opts, "block", "on");
+        }
         sock = inet_connect_opts(opts);
+    }
     qemu_opts_del(opts);
     return sock;
 }
diff --git a/qemu_socket.h b/qemu_socket.h
index a5d0a84..f73e26d 100644
--- a/qemu_socket.h
+++ b/qemu_socket.h
@@ -41,7 +41,7 @@ int inet_listen_opts(QemuOpts *opts, int port_offset);
 int inet_listen(const char *str, char *ostr, int olen,
                 int socktype, int port_offset);
 int inet_connect_opts(QemuOpts *opts);
-int inet_connect(const char *str, int socktype);
+int inet_connect(const char *str, bool block);
 int inet_dgram_opts(QemuOpts *opts);
 const char *inet_strfamily(int family);
 
diff --git a/ui/vnc.c b/ui/vnc.c
index deb9ecd..4a96153 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -3068,7 +3068,7 @@ int vnc_display_open(DisplayState *ds, const char 
*display)
         if (strncmp(display, "unix:", 5) == 0)
             vs->lsock = unix_connect(display+5);
         else
-            vs->lsock = inet_connect(display, SOCK_STREAM);
+            vs->lsock = inet_connect(display, true);
         if (-1 == vs->lsock) {
             g_free(vs->display);
             vs->display = NULL;