[Qemu-devel] [PATCH v12 2/4] sockets: change inet_connect() to support nonblock socket

[Amos Kong <akong@redhat.com>]

Add a bool argument to inet_connect() to assign if set socket
to block/nonblock, and delete original argument 'socktype'
that is unused.
Add a new argument to inet_connect()/inet_connect_opts(),
to pass back connect error by error class.

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

Change nbd, vnc to use new interface.

Signed-off-by: Amos Kong <akong@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 nbd.c          |    2 +-
 qemu-char.c    |    2 +-
 qemu-sockets.c |   43 +++++++++++++++++++++++++++++++++++++------
 qemu_socket.h  |    6 ++++--
 ui/vnc.c       |    2 +-
 5 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/nbd.c b/nbd.c
index 153709f..bebfc49 100644
--- a/nbd.c
+++ b/nbd.c
@@ -162,7 +162,7 @@ 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, NULL);
 }
 
 int tcp_socket_incoming(const char *address, uint16_t port)
diff --git a/qemu-char.c b/qemu-char.c
index a9fc504..060bf9d 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2446,7 +2446,7 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
         if (is_listen) {
             fd = inet_listen_opts(opts, 0);
         } else {
-            fd = inet_connect_opts(opts);
+            fd = inet_connect_opts(opts, NULL);
         }
     }
     if (fd < 0) {
diff --git a/qemu-sockets.c b/qemu-sockets.c
index 6bcb8e3..ce3f06c 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 */ }
     },
@@ -194,7 +197,7 @@ listen:
     return slisten;
 }
 
-int inet_connect_opts(QemuOpts *opts)
+int inet_connect_opts(QemuOpts *opts, Error **errp)
 {
     struct addrinfo ai,*res,*e;
     const char *addr;
@@ -202,6 +205,7 @@ int inet_connect_opts(QemuOpts *opts)
     char uaddr[INET6_ADDRSTRLEN+1];
     char uport[33];
     int sock,rc;
+    bool block;
 
     memset(&ai,0, sizeof(ai));
     ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
@@ -210,8 +214,10 @@ 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");
+        error_set(errp, QERR_SOCKET_CREATE_FAILED);
         return -1;
     }
 
@@ -224,6 +230,7 @@ int inet_connect_opts(QemuOpts *opts)
     if (0 != (rc = getaddrinfo(addr, port, &ai, &res))) {
         fprintf(stderr,"getaddrinfo(%s,%s): %s\n", addr, port,
                 gai_strerror(rc));
+        error_set(errp, QERR_SOCKET_CREATE_FAILED);
 	return -1;
     }
 
@@ -241,19 +248,37 @@ 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) {
+        do {
+            rc = 0;
+            if (connect(sock, e->ai_addr, e->ai_addrlen) < 0) {
+                rc = -socket_error();
+            }
+        } while (rc == -EINTR);
+
+  #ifdef _WIN32
+        if (!block && (rc == -EINPROGRESS || rc == -EWOULDBLOCK
+                       || rc == -WSAEALREADY)) {
+  #else
+        if (!block && (rc == -EINPROGRESS)) {
+  #endif
+            error_set(errp, QERR_SOCKET_CONNECT_IN_PROGRESS);
+        } else if (rc < 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);
+            sock = -1;
             continue;
         }
         freeaddrinfo(res);
         return sock;
     }
+    error_set(errp, QERR_SOCKET_CONNECT_FAILED);
     freeaddrinfo(res);
     return -1;
 }
@@ -449,14 +474,20 @@ 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, Error **errp)
 {
     QemuOpts *opts;
     int sock = -1;
 
     opts = qemu_opts_create(&dummy_opts, NULL, 0);
-    if (inet_parse(opts, str) == 0)
-        sock = inet_connect_opts(opts);
+    if (inet_parse(opts, str) == 0) {
+        if (block) {
+            qemu_opt_set(opts, "block", "on");
+        }
+        sock = inet_connect_opts(opts, errp);
+    } else {
+        error_set(errp, QERR_SOCKET_CREATE_FAILED);
+    }
     qemu_opts_del(opts);
     return sock;
 }
diff --git a/qemu_socket.h b/qemu_socket.h
index a5d0a84..26998ef 100644
--- a/qemu_socket.h
+++ b/qemu_socket.h
@@ -27,6 +27,8 @@ int inet_aton(const char *cp, struct in_addr *ia);
 #endif /* !_WIN32 */
 
 #include "qemu-option.h"
+#include "error.h"
+#include "qerror.h"
 
 /* misc helpers */
 int qemu_socket(int domain, int type, int protocol);
@@ -40,8 +42,8 @@ int send_all(int fd, const void *buf, int len1);
 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_opts(QemuOpts *opts, Error **errp);
+int inet_connect(const char *str, bool block, Error **errp);
 int inet_dgram_opts(QemuOpts *opts);
 const char *inet_strfamily(int family);
 
diff --git a/ui/vnc.c b/ui/vnc.c
index deb9ecd..3ae7704 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, NULL);
         if (-1 == vs->lsock) {
             g_free(vs->display);
             vs->display = NULL;