[Qemu-devel] [PATCH 0/2] net: clean up net/socket.c

[Qemu-devel] [PATCH 0/2] net: clean up net/socket.c

[Stefan Hajnoczi]

There is no consistent policy on closing the socket file descriptor when
net/socket.c initialization fails.  This has been on my TODO list for a while
and I had a few minutes to fix it now.

Stefan Hajnoczi (2):
  net: expand tabs in net/socket.c
  net: take ownership of fd in socket init functions

 net/socket.c |   88 ++++++++++++++++++++++++++++++---------------------------
 1 files changed, 46 insertions(+), 42 deletions(-)

-- 
1.7.7.3

[Qemu-devel] [PATCH 1/2] net: expand tabs in net/socket.c

[Stefan Hajnoczi]

In order to make later patches sane, expand the tab characters and
conform to QEMU coding style now.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 net/socket.c |   79 ++++++++++++++++++++++++++++++----------------------------
 1 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index e9ef128..613a7ef 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -161,10 +161,11 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
 #endif
 
     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
-	fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) does not contain a multicast address\n",
-		inet_ntoa(mcastaddr->sin_addr),
+        fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) "
+                "does not contain a multicast address\n",
+                inet_ntoa(mcastaddr->sin_addr),
                 (int)ntohl(mcastaddr->sin_addr.s_addr));
-	return -1;
+        return -1;
 
     }
     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
@@ -177,8 +178,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     ret=setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
                    (const char *)&val, sizeof(val));
     if (ret < 0) {
-	perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
-	goto fail;
+        perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
+        goto fail;
     }
 
     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
@@ -198,8 +199,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                      (const char *)&imr, sizeof(struct ip_mreq));
     if (ret < 0) {
-	perror("setsockopt(IP_ADD_MEMBERSHIP)");
-	goto fail;
+        perror("setsockopt(IP_ADD_MEMBERSHIP)");
+        goto fail;
     }
 
     /* Force mcast msgs to loopback (eg. several QEMUs in same host */
@@ -207,8 +208,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     ret=setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
                    (const char *)&loop, sizeof(loop));
     if (ret < 0) {
-	perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
-	goto fail;
+        perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
+        goto fail;
     }
 
     /* If a bind address is given, only send packets from that address */
@@ -260,37 +261,38 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
      */
 
     if (is_connected) {
-	if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
-	    /* must be bound */
-	    if (saddr.sin_addr.s_addr==0) {
-		fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, cannot setup multicast dst addr\n",
-			fd);
-		return NULL;
-	    }
-	    /* clone dgram socket */
-	    newfd = net_socket_mcast_create(&saddr, NULL);
-	    if (newfd < 0) {
-		/* error already reported by net_socket_mcast_create() */
-		close(fd);
-		return NULL;
-	    }
-	    /* clone newfd to fd, close newfd */
-	    dup2(newfd, fd);
-	    close(newfd);
-
-	} else {
-	    fprintf(stderr, "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
-		    fd, strerror(errno));
-	    return NULL;
-	}
+        if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
+            /* must be bound */
+            if (saddr.sin_addr.s_addr == 0) {
+                fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
+                        "cannot setup multicast dst addr\n", fd);
+                return NULL;
+            }
+            /* clone dgram socket */
+            newfd = net_socket_mcast_create(&saddr, NULL);
+            if (newfd < 0) {
+                /* error already reported by net_socket_mcast_create() */
+                close(fd);
+                return NULL;
+            }
+            /* clone newfd to fd, close newfd */
+            dup2(newfd, fd);
+            close(newfd);
+
+        } else {
+            fprintf(stderr,
+                    "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
+                    fd, strerror(errno));
+            return NULL;
+        }
     }
 
     nc = qemu_new_net_client(&net_dgram_socket_info, vlan, NULL, model, name);
 
     snprintf(nc->info_str, sizeof(nc->info_str),
-	    "socket: fd=%d (%s mcast=%s:%d)",
-	    fd, is_connected ? "cloned" : "",
-	    inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+            "socket: fd=%d (%s mcast=%s:%d)",
+            fd, is_connected ? "cloned" : "",
+            inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
 
     s = DO_UPCAST(NetSocketState, nc, nc);
 
@@ -349,8 +351,9 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
 
     if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
         (socklen_t *)&optlen)< 0) {
-	fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n", fd);
-	return NULL;
+        fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
+                fd);
+        return NULL;
     }
     switch(so_type) {
     case SOCK_DGRAM:
@@ -509,7 +512,7 @@ static int net_socket_mcast_init(VLANState *vlan,
 
     fd = net_socket_mcast_create(&saddr, param_localaddr);
     if (fd < 0)
-	return -1;
+        return -1;
 
     s = net_socket_fd_init(vlan, model, name, fd, 0);
     if (!s)
-- 
1.7.7.3

[Qemu-devel] [PATCH 2/2] net: take ownership of fd in socket init functions

[Stefan Hajnoczi]

Today net/socket.c has no consistent policy for closing the socket file
descriptor when initialization fails.  This means we leak the file
descriptor in some cases or we could also try to close it twice.

Make error paths consistent by taking ownership of the file descriptor
and closing it on error.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 net/socket.c |   17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 613a7ef..f999c26 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -266,14 +266,13 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
             if (saddr.sin_addr.s_addr == 0) {
                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
                         "cannot setup multicast dst addr\n", fd);
-                return NULL;
+                goto err;
             }
             /* clone dgram socket */
             newfd = net_socket_mcast_create(&saddr, NULL);
             if (newfd < 0) {
                 /* error already reported by net_socket_mcast_create() */
-                close(fd);
-                return NULL;
+                goto err;
             }
             /* clone newfd to fd, close newfd */
             dup2(newfd, fd);
@@ -283,7 +282,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
             fprintf(stderr,
                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
                     fd, strerror(errno));
-            return NULL;
+            goto err;
         }
     }
 
@@ -304,6 +303,10 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
     if (is_connected) s->dgram_dst=saddr;
 
     return s;
+
+err:
+    closesocket(fd);
+    return NULL;
 }
 
 static void net_socket_connect(void *opaque)
@@ -353,6 +356,7 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
         (socklen_t *)&optlen)< 0) {
         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
                 fd);
+        closesocket(fd);
         return NULL;
     }
     switch(so_type) {
@@ -386,9 +390,7 @@ static void net_socket_accept(void *opaque)
         }
     }
     s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1);
-    if (!s1) {
-        closesocket(fd);
-    } else {
+    if (s1) {
         snprintf(s1->nc.info_str, sizeof(s1->nc.info_str),
                  "socket: connection from %s:%d",
                  inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
@@ -549,7 +551,6 @@ int net_init_socket(QemuOpts *opts,
         }
 
         if (!net_socket_fd_init(vlan, "socket", name, fd, 1)) {
-            close(fd);
             return -1;
         }
     } else if (qemu_opt_get(opts, "listen")) {
-- 
1.7.7.3

Re: [Qemu-devel] [PATCH 1/2] net: expand tabs in net/socket.c

[Zhi Yong Wu]

On Wed, Dec 7, 2011 at 11:01 PM, Stefan Hajnoczi
<stefanha@linux.vnet.ibm.com> wrote:
> In order to make later patches sane, expand the tab characters and
> conform to QEMU coding style now.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  net/socket.c |   79 ++++++++++++++++++++++++++++++----------------------------
>  1 files changed, 41 insertions(+), 38 deletions(-)
>
> diff --git a/net/socket.c b/net/socket.c
> index e9ef128..613a7ef 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -161,10 +161,11 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
>  #endif
>
>     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
> -       fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) does not contain a multicast address\n",
> -               inet_ntoa(mcastaddr->sin_addr),
> +        fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) "
> +                "does not contain a multicast address\n",
> +                inet_ntoa(mcastaddr->sin_addr),
>                 (int)ntohl(mcastaddr->sin_addr.s_addr));
> -       return -1;
> +        return -1;
>
>     }
>     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
> @@ -177,8 +178,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
>     ret=setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
>                    (const char *)&val, sizeof(val));
>     if (ret < 0) {
> -       perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
> -       goto fail;
> +        perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
> +        goto fail;
>     }
>
>     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
> @@ -198,8 +199,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
>     ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
>                      (const char *)&imr, sizeof(struct ip_mreq));
>     if (ret < 0) {
> -       perror("setsockopt(IP_ADD_MEMBERSHIP)");
> -       goto fail;
> +        perror("setsockopt(IP_ADD_MEMBERSHIP)");
> +        goto fail;
>     }
>
>     /* Force mcast msgs to loopback (eg. several QEMUs in same host */
> @@ -207,8 +208,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
>     ret=setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
>                    (const char *)&loop, sizeof(loop));
>     if (ret < 0) {
> -       perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
> -       goto fail;
> +        perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
> +        goto fail;
>     }
>
>     /* If a bind address is given, only send packets from that address */
> @@ -260,37 +261,38 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>      */
>
>     if (is_connected) {
> -       if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
> -           /* must be bound */
> -           if (saddr.sin_addr.s_addr==0) {
> -               fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, cannot setup multicast dst addr\n",
> -                       fd);
> -               return NULL;
> -           }
> -           /* clone dgram socket */
> -           newfd = net_socket_mcast_create(&saddr, NULL);
> -           if (newfd < 0) {
> -               /* error already reported by net_socket_mcast_create() */
> -               close(fd);
> -               return NULL;
> -           }
> -           /* clone newfd to fd, close newfd */
> -           dup2(newfd, fd);
> -           close(newfd);
> -
> -       } else {
> -           fprintf(stderr, "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
> -                   fd, strerror(errno));
> -           return NULL;
> -       }
> +        if (getsockname(fd, (struct sockaddr *) &saddr, &saddr_len) == 0) {
> +            /* must be bound */
> +            if (saddr.sin_addr.s_addr == 0) {
> +                fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
> +                        "cannot setup multicast dst addr\n", fd);
> +                return NULL;
> +            }
> +            /* clone dgram socket */
> +            newfd = net_socket_mcast_create(&saddr, NULL);
> +            if (newfd < 0) {
> +                /* error already reported by net_socket_mcast_create() */
> +                close(fd);
> +                return NULL;
> +            }
> +            /* clone newfd to fd, close newfd */
> +            dup2(newfd, fd);
> +            close(newfd);
> +
The above white line should be removed.
> +        } else {
> +            fprintf(stderr,
> +                    "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
> +                    fd, strerror(errno));
> +            return NULL;
> +        }
>     }
>
>     nc = qemu_new_net_client(&net_dgram_socket_info, vlan, NULL, model, name);
>
>     snprintf(nc->info_str, sizeof(nc->info_str),
> -           "socket: fd=%d (%s mcast=%s:%d)",
> -           fd, is_connected ? "cloned" : "",
> -           inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
> +            "socket: fd=%d (%s mcast=%s:%d)",
> +            fd, is_connected ? "cloned" : "",
> +            inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
>
>     s = DO_UPCAST(NetSocketState, nc, nc);
>
> @@ -349,8 +351,9 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
>
>     if(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&so_type,
>         (socklen_t *)&optlen)< 0) {
> -       fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n", fd);
> -       return NULL;
> +        fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
> +                fd);
> +        return NULL;
>     }
>     switch(so_type) {
>     case SOCK_DGRAM:
> @@ -509,7 +512,7 @@ static int net_socket_mcast_init(VLANState *vlan,
>
>     fd = net_socket_mcast_create(&saddr, param_localaddr);
>     if (fd < 0)
> -       return -1;
> +        return -1;
>
>     s = net_socket_fd_init(vlan, model, name, fd, 0);
>     if (!s)
> --
> 1.7.7.3
>
>



-- 
Regards,

Zhi Yong Wu

Re: [Qemu-devel] [PATCH 2/2] net: take ownership of fd in socket init functions

[Zhi Yong Wu]

On Wed, Dec 7, 2011 at 11:01 PM, Stefan Hajnoczi
<stefanha@linux.vnet.ibm.com> wrote:
> Today net/socket.c has no consistent policy for closing the socket file
> descriptor when initialization fails.  This means we leak the file
> descriptor in some cases or we could also try to close it twice.
>
> Make error paths consistent by taking ownership of the file descriptor
> and closing it on error.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  net/socket.c |   17 +++++++++--------
>  1 files changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/net/socket.c b/net/socket.c
> index 613a7ef..f999c26 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -266,14 +266,13 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>             if (saddr.sin_addr.s_addr == 0) {
>                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
>                         "cannot setup multicast dst addr\n", fd);
> -                return NULL;
> +                goto err;
>             }
>             /* clone dgram socket */
>             newfd = net_socket_mcast_create(&saddr, NULL);
>             if (newfd < 0) {
>                 /* error already reported by net_socket_mcast_create() */
> -                close(fd);
> -                return NULL;
> +                goto err;
>             }
>             /* clone newfd to fd, close newfd */
>             dup2(newfd, fd);
> @@ -283,7 +282,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>             fprintf(stderr,
>                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
>                     fd, strerror(errno));
> -            return NULL;
> +            goto err;
>         }
>     }
>
> @@ -304,6 +303,10 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>     if (is_connected) s->dgram_dst=saddr;
>
>     return s;
> +
> +err:
> +    closesocket(fd);
> +    return NULL;
>  }
>
>  static void net_socket_connect(void *opaque)
> @@ -353,6 +356,7 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
>         (socklen_t *)&optlen)< 0) {
>         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
>                 fd);
> +        closesocket(fd);
>         return NULL;
>     }
>     switch(so_type) {
> @@ -386,9 +390,7 @@ static void net_socket_accept(void *opaque)
>         }
>     }
>     s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1);
> -    if (!s1) {
> -        closesocket(fd);
> -    } else {
Why is it not handled when s1 is NULL?
> +    if (s1) {
>         snprintf(s1->nc.info_str, sizeof(s1->nc.info_str),
>                  "socket: connection from %s:%d",
>                  inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
> @@ -549,7 +551,6 @@ int net_init_socket(QemuOpts *opts,
>         }
>
>         if (!net_socket_fd_init(vlan, "socket", name, fd, 1)) {
> -            close(fd);
>             return -1;
>         }
>     } else if (qemu_opt_get(opts, "listen")) {
> --
> 1.7.7.3
>
>



-- 
Regards,

Zhi Yong Wu

Re: [Qemu-devel] [PATCH 2/2] net: take ownership of fd in socket init functions

[Stefan Hajnoczi]

On Thu, Dec 8, 2011 at 12:29 PM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
> On Wed, Dec 7, 2011 at 11:01 PM, Stefan Hajnoczi
> <stefanha@linux.vnet.ibm.com> wrote:
>> Today net/socket.c has no consistent policy for closing the socket file
>> descriptor when initialization fails.  This means we leak the file
>> descriptor in some cases or we could also try to close it twice.
>>
>> Make error paths consistent by taking ownership of the file descriptor
>> and closing it on error.
>>
>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>> ---
>>  net/socket.c |   17 +++++++++--------
>>  1 files changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/net/socket.c b/net/socket.c
>> index 613a7ef..f999c26 100644
>> --- a/net/socket.c
>> +++ b/net/socket.c
>> @@ -266,14 +266,13 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>             if (saddr.sin_addr.s_addr == 0) {
>>                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
>>                         "cannot setup multicast dst addr\n", fd);
>> -                return NULL;
>> +                goto err;
>>             }
>>             /* clone dgram socket */
>>             newfd = net_socket_mcast_create(&saddr, NULL);
>>             if (newfd < 0) {
>>                 /* error already reported by net_socket_mcast_create() */
>> -                close(fd);
>> -                return NULL;
>> +                goto err;
>>             }
>>             /* clone newfd to fd, close newfd */
>>             dup2(newfd, fd);
>> @@ -283,7 +282,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>             fprintf(stderr,
>>                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
>>                     fd, strerror(errno));
>> -            return NULL;
>> +            goto err;
>>         }
>>     }
>>
>> @@ -304,6 +303,10 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>     if (is_connected) s->dgram_dst=saddr;
>>
>>     return s;
>> +
>> +err:
>> +    closesocket(fd);
>> +    return NULL;
>>  }
>>
>>  static void net_socket_connect(void *opaque)
>> @@ -353,6 +356,7 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
>>         (socklen_t *)&optlen)< 0) {
>>         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
>>                 fd);
>> +        closesocket(fd);
>>         return NULL;
>>     }
>>     switch(so_type) {
>> @@ -386,9 +390,7 @@ static void net_socket_accept(void *opaque)
>>         }
>>     }
>>     s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1);
>> -    if (!s1) {
>> -        closesocket(fd);
>> -    } else {
> Why is it not handled when s1 is NULL?

The point of the patch is to introduce consistent error behavior -
net_socket_fd_init() will close the socket on error so we no longer
have to do that.  If you look at net_socket_accept() there is nothing
else to do on failure it was possible to just remove the if (!s1)
check.

Stefan

Re: [Qemu-devel] [PATCH 2/2] net: take ownership of fd in socket init functions

[Zhi Yong Wu]

On Thu, Dec 8, 2011 at 8:57 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Thu, Dec 8, 2011 at 12:29 PM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
>> On Wed, Dec 7, 2011 at 11:01 PM, Stefan Hajnoczi
>> <stefanha@linux.vnet.ibm.com> wrote:
>>> Today net/socket.c has no consistent policy for closing the socket file
>>> descriptor when initialization fails.  This means we leak the file
>>> descriptor in some cases or we could also try to close it twice.
>>>
>>> Make error paths consistent by taking ownership of the file descriptor
>>> and closing it on error.
>>>
>>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>>> ---
>>>  net/socket.c |   17 +++++++++--------
>>>  1 files changed, 9 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/net/socket.c b/net/socket.c
>>> index 613a7ef..f999c26 100644
>>> --- a/net/socket.c
>>> +++ b/net/socket.c
>>> @@ -266,14 +266,13 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>>             if (saddr.sin_addr.s_addr == 0) {
>>>                 fprintf(stderr, "qemu: error: init_dgram: fd=%d unbound, "
>>>                         "cannot setup multicast dst addr\n", fd);
>>> -                return NULL;
>>> +                goto err;
>>>             }
>>>             /* clone dgram socket */
>>>             newfd = net_socket_mcast_create(&saddr, NULL);
>>>             if (newfd < 0) {
>>>                 /* error already reported by net_socket_mcast_create() */
>>> -                close(fd);
>>> -                return NULL;
>>> +                goto err;
>>>             }
>>>             /* clone newfd to fd, close newfd */
>>>             dup2(newfd, fd);
>>> @@ -283,7 +282,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>>             fprintf(stderr,
>>>                     "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
>>>                     fd, strerror(errno));
>>> -            return NULL;
>>> +            goto err;
>>>         }
>>>     }
>>>
>>> @@ -304,6 +303,10 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan,
>>>     if (is_connected) s->dgram_dst=saddr;
>>>
>>>     return s;
>>> +
>>> +err:
>>> +    closesocket(fd);
>>> +    return NULL;
>>>  }
>>>
>>>  static void net_socket_connect(void *opaque)
>>> @@ -353,6 +356,7 @@ static NetSocketState *net_socket_fd_init(VLANState *vlan,
>>>         (socklen_t *)&optlen)< 0) {
>>>         fprintf(stderr, "qemu: error: getsockopt(SO_TYPE) for fd=%d failed\n",
>>>                 fd);
>>> +        closesocket(fd);
>>>         return NULL;
>>>     }
>>>     switch(so_type) {
>>> @@ -386,9 +390,7 @@ static void net_socket_accept(void *opaque)
>>>         }
>>>     }
>>>     s1 = net_socket_fd_init(s->vlan, s->model, s->name, fd, 1);
>>> -    if (!s1) {
>>> -        closesocket(fd);
>>> -    } else {
>> Why is it not handled when s1 is NULL?
>
> The point of the patch is to introduce consistent error behavior -
> net_socket_fd_init() will close the socket on error so we no longer
> have to do that.  If you look at net_socket_accept() there is nothing
> else to do on failure it was possible to just remove the if (!s1)
> check.
You are right, thanks.
>
> Stefan



-- 
Regards,

Zhi Yong Wu

Re: [Qemu-devel] [PATCH 0/2] net: clean up net/socket.c

[Anthony Liguori]

On 12/07/2011 09:01 AM, Stefan Hajnoczi wrote:
> There is no consistent policy on closing the socket file descriptor when
> net/socket.c initialization fails.  This has been on my TODO list for a while
> and I had a few minutes to fix it now.

Applied all.  Thanks.

Regards,

Anthony Liguori

>
> Stefan Hajnoczi (2):
>    net: expand tabs in net/socket.c
>    net: take ownership of fd in socket init functions
>
>   net/socket.c |   88 ++++++++++++++++++++++++++++++---------------------------
>   1 files changed, 46 insertions(+), 42 deletions(-)
>