[Qemu-devel] [PATCH v6 0/4] Improve error reporting

[Qemu-devel] [PATCH v6 0/4] Improve error reporting

[Mao Zhongyi]

v6:
* PATCH 02
  -rename the subject
  -drop the "qemu: error: " prefix.
  -correct inappropriate error information settings.
* PATCH 03,04
  -correct inappropriate error information settings.    [Markus Armbruster]

v5:
* PATCH 01 make the commit message more exact about the actual function.    [Markus Armbruster]
* PATCH 02, 03, 04 still retains the original function, but specific
           content and order of each patch has been adjusted substantially, 
           so that ensure each patch is a completed fix.    [Markus Armbruster]

v4: 
* PATCH 01 is redoing previous patch 1, replace the fprintf() with error_report()
		     in the 'default' case of net_socket_fd_init() [Markus Armbruster]

v3:
* PATCH 01 is suggested by Markus and Daniel that removes the dubious 'default' case
           in the net_socket_fd_init(). Jason agreed.
* PATCH 02 is redoing previous patch 4.
* PATCH 04 is redoing previous patch 2, improves sort of error messages. 

v2:
* PATCH 02 reworking of patch 2 following Markus's suggestion that convert error_report()
           in the function called by net_socket_*_init() to Error. Also add many error 
           handling information.
* PATCH 03 net_socket_mcast_create(), net_socket_fd_init_dgram() and net_socket_fd_init() 
           use the function such as fprintf, perror to report an error message. Convert it 
           to Error.
* PATCH 04 parse_host_port() may fail without reporting an error. Now, fix it to set an
           error when it fails.


Cc: jasowang@redhat.com
Cc: armbru@redhat.com
Cc: berrange@redhat.com
Cc: kraxel@redhat.com
Cc: pbonzini@redhat.com

Mao Zhongyi (4):
  net/socket: Don't treat odd socket type as SOCK_STREAM
  net/socket: Convert several helper functions to Error
  net/net: Convert parse_host_port() to Error
  net/socket: Improve -net socket error reporting

 include/qemu/sockets.h |   3 +-
 net/net.c              |  23 ++++++--
 net/socket.c           | 146 ++++++++++++++++++++++++++++---------------------
 3 files changed, 105 insertions(+), 67 deletions(-)

-- 
2.9.4

[Qemu-devel] [PATCH v6 1/4] net/socket: Don't treat odd socket type as SOCK_STREAM

[Mao Zhongyi]

In net_socket_fd_init(), the 'default' case is odd: it warns,
then continues as if the socket type was SOCK_STREAM. The
comment explains "this could be a eg. a pty", but that makes
no sense. If @fd really was a pty, getsockopt() would fail
with ENOTSOCK. If @fd was a socket, but neither SOCK_DGRAM nor
SOCK_STREAM. It should not be treated as if it was SOCK_STREAM.

Turn this case into an Error. If there is a genuine reason to
support something like SOCK_RAW, it should be explicitly
handled.

Cc: jasowang@redhat.com
Cc: armbru@redhat.com
Cc: berrange@redhat.com
Cc: armbru@redhat.com
Suggested-by: Markus Armbruster <armbru@redhat.com>
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
---
 net/socket.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index dcae1ae..53765bd 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -449,9 +449,9 @@ static NetSocketState *net_socket_fd_init(NetClientState *peer,
     case SOCK_STREAM:
         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
     default:
-        /* who knows ... this could be a eg. a pty, do warn and continue as stream */
-        fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
-        return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
+        error_report("qemu: error: socket type=%d for fd=%d is not"
+                " SOCK_DGRAM or SOCK_STREAM", so_type, fd);
+        closesocket(fd);
     }
     return NULL;
 }
-- 
2.9.4

[Qemu-devel] [PATCH v6 2/4] net/socket: Convert several helper functions to Error

[Mao Zhongyi]

Currently, net_socket_mcast_create(), net_socket_fd_init_dgram() and
net_socket_fd_init() use the function such as fprintf(), perror() to
report an error message.

Now, convert these functions to Error.

Cc: jasowang@redhat.com
Cc: armbru@redhat.com
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
---
 net/socket.c | 75 +++++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 47 insertions(+), 28 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 53765bd..b6bacf4 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -209,7 +209,9 @@ static void net_socket_send_dgram(void *opaque)
     }
 }
 
-static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr *localaddr)
+static int net_socket_mcast_create(struct sockaddr_in *mcastaddr,
+                                   struct in_addr *localaddr,
+                                   Error **errp)
 {
     struct ip_mreq imr;
     int fd;
@@ -221,8 +223,8 @@ 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",
+        error_setg(errp, "specified mcastaddr %s (0x%08x) "
+                "does not contain a multicast address",
                 inet_ntoa(mcastaddr->sin_addr),
                 (int)ntohl(mcastaddr->sin_addr.s_addr));
         return -1;
@@ -230,7 +232,7 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     }
     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
     if (fd < 0) {
-        perror("socket(PF_INET, SOCK_DGRAM)");
+        error_setg_errno(errp, errno, "failed to create datagram socket");
         return -1;
     }
 
@@ -242,13 +244,15 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     val = 1;
     ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
     if (ret < 0) {
-        perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
+        error_setg_errno(errp, errno, "set the socket 'SO_REUSEADDR'"
+                         " attribute failed");
         goto fail;
     }
 
     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
     if (ret < 0) {
-        perror("bind");
+        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
+                         inet_ntoa(mcastaddr->sin_addr));
         goto fail;
     }
 
@@ -263,7 +267,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                           &imr, sizeof(struct ip_mreq));
     if (ret < 0) {
-        perror("setsockopt(IP_ADD_MEMBERSHIP)");
+        error_setg_errno(errp, errno, "add socket to multicast group %s"
+                         " failed", inet_ntoa(imr.imr_multiaddr));
         goto fail;
     }
 
@@ -272,7 +277,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
     ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP,
                           &loop, sizeof(loop));
     if (ret < 0) {
-        perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
+        error_setg_errno(errp, errno, "force multicast message to loopback"
+                         " failed");
         goto fail;
     }
 
@@ -281,7 +287,8 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
         ret = qemu_setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF,
                               localaddr, sizeof(*localaddr));
         if (ret < 0) {
-            perror("setsockopt(IP_MULTICAST_IF)");
+            error_setg_errno(errp, errno, "set the default network send "
+                             "interface failed");
             goto fail;
         }
     }
@@ -320,7 +327,8 @@ static NetClientInfo net_dgram_socket_info = {
 static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
                                                 const char *model,
                                                 const char *name,
-                                                int fd, int is_connected)
+                                                int fd, int is_connected,
+                                                Error **errp)
 {
     struct sockaddr_in saddr;
     int newfd;
@@ -337,14 +345,13 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
         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);
+                error_setg(errp, "init_dgram: fd=%d unbound, "
+                        "cannot setup multicast dst addr", fd);
                 goto err;
             }
             /* clone dgram socket */
-            newfd = net_socket_mcast_create(&saddr, NULL);
+            newfd = net_socket_mcast_create(&saddr, NULL, errp);
             if (newfd < 0) {
-                /* error already reported by net_socket_mcast_create() */
                 goto err;
             }
             /* clone newfd to fd, close newfd */
@@ -352,8 +359,8 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
             close(newfd);
 
         } else {
-            fprintf(stderr,
-                    "qemu: error: init_dgram: fd=%d failed getsockname(): %s\n",
+            error_setg(errp,
+                    "init_dgram: fd=%d failed getsockname(): %s",
                     fd, strerror(errno));
             goto err;
         }
@@ -432,24 +439,26 @@ static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
 
 static NetSocketState *net_socket_fd_init(NetClientState *peer,
                                           const char *model, const char *name,
-                                          int fd, int is_connected)
+                                          int fd, int is_connected,
+                                          Error **errp)
 {
     int so_type = -1, optlen=sizeof(so_type);
 
     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",
+        error_setg(errp, "getsockopt(SO_TYPE) for fd=%d failed",
                 fd);
         closesocket(fd);
         return NULL;
     }
     switch(so_type) {
     case SOCK_DGRAM:
-        return net_socket_fd_init_dgram(peer, model, name, fd, is_connected);
+        return net_socket_fd_init_dgram(peer, model, name, fd, is_connected,
+                                        errp);
     case SOCK_STREAM:
         return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
     default:
-        error_report("qemu: error: socket type=%d for fd=%d is not"
+        error_setg(errp, "socket type=%d for fd=%d is not"
                 " SOCK_DGRAM or SOCK_STREAM", so_type, fd);
         closesocket(fd);
     }
@@ -536,6 +545,7 @@ static int net_socket_connect_init(NetClientState *peer,
     NetSocketState *s;
     int fd, connected, ret;
     struct sockaddr_in saddr;
+    Error *err = NULL;
 
     if (parse_host_port(&saddr, host_str) < 0)
         return -1;
@@ -567,9 +577,11 @@ static int net_socket_connect_init(NetClientState *peer,
             break;
         }
     }
-    s = net_socket_fd_init(peer, model, name, fd, connected);
-    if (!s)
+    s = net_socket_fd_init(peer, model, name, fd, connected, &err);
+    if (!s) {
+        error_report_err(err);
         return -1;
+    }
     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
              "socket: connect to %s:%d",
              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
@@ -586,6 +598,7 @@ static int net_socket_mcast_init(NetClientState *peer,
     int fd;
     struct sockaddr_in saddr;
     struct in_addr localaddr, *param_localaddr;
+    Error *err = NULL;
 
     if (parse_host_port(&saddr, host_str) < 0)
         return -1;
@@ -598,13 +611,17 @@ static int net_socket_mcast_init(NetClientState *peer,
         param_localaddr = NULL;
     }
 
-    fd = net_socket_mcast_create(&saddr, param_localaddr);
-    if (fd < 0)
+    fd = net_socket_mcast_create(&saddr, param_localaddr, &err);
+    if (fd < 0) {
+        error_report_err(err);
         return -1;
+    }
 
-    s = net_socket_fd_init(peer, model, name, fd, 0);
-    if (!s)
+    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
+    if (!s) {
+        error_report_err(err);
         return -1;
+    }
 
     s->dgram_dst = saddr;
 
@@ -624,6 +641,7 @@ static int net_socket_udp_init(NetClientState *peer,
     NetSocketState *s;
     int fd, ret;
     struct sockaddr_in laddr, raddr;
+    Error *err = NULL;
 
     if (parse_host_port(&laddr, lhost) < 0) {
         return -1;
@@ -652,8 +670,9 @@ static int net_socket_udp_init(NetClientState *peer,
     }
     qemu_set_nonblock(fd);
 
-    s = net_socket_fd_init(peer, model, name, fd, 0);
+    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
     if (!s) {
+        error_report_err(err);
         return -1;
     }
 
@@ -696,7 +715,7 @@ int net_init_socket(const Netdev *netdev, const char *name,
             return -1;
         }
         qemu_set_nonblock(fd);
-        if (!net_socket_fd_init(peer, "socket", name, fd, 1)) {
+        if (!net_socket_fd_init(peer, "socket", name, fd, 1, errp)) {
             return -1;
         }
         return 0;
-- 
2.9.4

[Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Mao Zhongyi]

Cc: berrange@redhat.com
Cc: kraxel@redhat.com
Cc: pbonzini@redhat.com
Cc: jasowang@redhat.com
Cc: armbru@redhat.com
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
---
 include/qemu/sockets.h |  3 ++-
 net/net.c              | 23 ++++++++++++++++++-----
 net/socket.c           | 19 ++++++++++++++-----
 3 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
index 5c326db..78e2b30 100644
--- a/include/qemu/sockets.h
+++ b/include/qemu/sockets.h
@@ -53,7 +53,8 @@ void socket_listen_cleanup(int fd, Error **errp);
 int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp);
 
 /* Old, ipv4 only bits.  Don't use for new code. */
-int parse_host_port(struct sockaddr_in *saddr, const char *str);
+int parse_host_port(struct sockaddr_in *saddr, const char *str,
+                    Error **errp);
 int socket_init(void);
 
 /**
diff --git a/net/net.c b/net/net.c
index 6235aab..29cc7df 100644
--- a/net/net.c
+++ b/net/net.c
@@ -100,7 +100,8 @@ static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
     return 0;
 }
 
-int parse_host_port(struct sockaddr_in *saddr, const char *str)
+int parse_host_port(struct sockaddr_in *saddr, const char *str,
+                    Error **errp)
 {
     char buf[512];
     struct hostent *he;
@@ -108,24 +109,36 @@ int parse_host_port(struct sockaddr_in *saddr, const char *str)
     int port;
 
     p = str;
-    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0)
+    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0) {
+        error_setg(errp, "host address '%s' doesn't contain ':' "
+                   "separating host from port", str);
         return -1;
+    }
     saddr->sin_family = AF_INET;
     if (buf[0] == '\0') {
         saddr->sin_addr.s_addr = 0;
     } else {
         if (qemu_isdigit(buf[0])) {
-            if (!inet_aton(buf, &saddr->sin_addr))
+            if (!inet_aton(buf, &saddr->sin_addr)) {
+                error_setg(errp, "host address '%s' is not a valid "
+                           "IPv4 address", buf);
                 return -1;
+            }
         } else {
-            if ((he = gethostbyname(buf)) == NULL)
+            he = gethostbyname(buf);
+            if (he == NULL) {
+                error_setg(errp, "can't resolve host address '%s': "
+                           "unknown host", buf);
                 return - 1;
+            }
             saddr->sin_addr = *(struct in_addr *)he->h_addr;
         }
     }
     port = strtol(p, (char **)&r, 0);
-    if (r == p)
+    if (r == p) {
+        error_setg(errp, "port number '%s' is invalid", p);
         return -1;
+    }
     saddr->sin_port = htons(port);
     return 0;
 }
diff --git a/net/socket.c b/net/socket.c
index b6bacf4..90dd4c0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -500,9 +500,12 @@ static int net_socket_listen_init(NetClientState *peer,
     NetSocketState *s;
     struct sockaddr_in saddr;
     int fd, ret;
+    Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str) < 0)
+    if (parse_host_port(&saddr, host_str, &err) < 0) {
+        error_report_err(err);
         return -1;
+    }
 
     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
     if (fd < 0) {
@@ -547,8 +550,10 @@ static int net_socket_connect_init(NetClientState *peer,
     struct sockaddr_in saddr;
     Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str) < 0)
+    if (parse_host_port(&saddr, host_str, &err) < 0) {
+        error_report_err(err);
         return -1;
+    }
 
     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
     if (fd < 0) {
@@ -600,8 +605,10 @@ static int net_socket_mcast_init(NetClientState *peer,
     struct in_addr localaddr, *param_localaddr;
     Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str) < 0)
+    if (parse_host_port(&saddr, host_str, &err) < 0) {
+        error_report_err(err);
         return -1;
+    }
 
     if (localaddr_str != NULL) {
         if (inet_aton(localaddr_str, &localaddr) == 0)
@@ -643,11 +650,13 @@ static int net_socket_udp_init(NetClientState *peer,
     struct sockaddr_in laddr, raddr;
     Error *err = NULL;
 
-    if (parse_host_port(&laddr, lhost) < 0) {
+    if (parse_host_port(&laddr, lhost, &err) < 0) {
+        error_report_err(err);
         return -1;
     }
 
-    if (parse_host_port(&raddr, rhost) < 0) {
+    if (parse_host_port(&raddr, rhost, &err) < 0) {
+        error_report_err(err);
         return -1;
     }
 
-- 
2.9.4

[Qemu-devel] [PATCH v6 4/4] net/socket: Improve -net socket error reporting

[Mao Zhongyi]

When -net socket fails, it first reports a specific error, then
a generic one, like this:

    $ qemu-system-x86_64 -net socket,
    qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
    qemu-system-x86_64: -net socket: Device 'socket' could not be initialized

Convert net_socket_*_init() to Error to get rid of the superfluous second
error message. After the patch, the effect like this:

    $ qemu-system-x86_64 -net socket,
    qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required

At the same time, add many explicit error handling message when it fails.

Cc: jasowang@redhat.com
Cc: armbru@redhat.com
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
---
 net/socket.c | 92 +++++++++++++++++++++++++++++-------------------------------
 1 file changed, 44 insertions(+), 48 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 90dd4c0..47e6706 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -494,22 +494,21 @@ static void net_socket_accept(void *opaque)
 static int net_socket_listen_init(NetClientState *peer,
                                   const char *model,
                                   const char *name,
-                                  const char *host_str)
+                                  const char *host_str,
+                                  Error **errp)
 {
     NetClientState *nc;
     NetSocketState *s;
     struct sockaddr_in saddr;
     int fd, ret;
-    Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str, &err) < 0) {
-        error_report_err(err);
+    if (parse_host_port(&saddr, host_str, errp) < 0) {
         return -1;
     }
 
     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
     if (fd < 0) {
-        perror("socket");
+        error_setg_errno(errp, errno, "failed to create stream socket");
         return -1;
     }
     qemu_set_nonblock(fd);
@@ -518,13 +517,14 @@ static int net_socket_listen_init(NetClientState *peer,
 
     ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
     if (ret < 0) {
-        perror("bind");
+        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
+                         inet_ntoa(saddr.sin_addr));
         closesocket(fd);
         return -1;
     }
     ret = listen(fd, 0);
     if (ret < 0) {
-        perror("listen");
+        error_setg_errno(errp, errno, "listen socket failed");
         closesocket(fd);
         return -1;
     }
@@ -543,21 +543,20 @@ static int net_socket_listen_init(NetClientState *peer,
 static int net_socket_connect_init(NetClientState *peer,
                                    const char *model,
                                    const char *name,
-                                   const char *host_str)
+                                   const char *host_str,
+                                   Error **errp)
 {
     NetSocketState *s;
     int fd, connected, ret;
     struct sockaddr_in saddr;
-    Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str, &err) < 0) {
-        error_report_err(err);
+    if (parse_host_port(&saddr, host_str, errp) < 0) {
         return -1;
     }
 
     fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
     if (fd < 0) {
-        perror("socket");
+        error_setg_errno(errp, errno, "failed to create stream socket");
         return -1;
     }
     qemu_set_nonblock(fd);
@@ -573,7 +572,7 @@ static int net_socket_connect_init(NetClientState *peer,
                        errno == EINVAL) {
                 break;
             } else {
-                perror("connect");
+                error_setg_errno(errp, errno, "connection failed");
                 closesocket(fd);
                 return -1;
             }
@@ -582,9 +581,8 @@ static int net_socket_connect_init(NetClientState *peer,
             break;
         }
     }
-    s = net_socket_fd_init(peer, model, name, fd, connected, &err);
+    s = net_socket_fd_init(peer, model, name, fd, connected, errp);
     if (!s) {
-        error_report_err(err);
         return -1;
     }
     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
@@ -597,36 +595,36 @@ static int net_socket_mcast_init(NetClientState *peer,
                                  const char *model,
                                  const char *name,
                                  const char *host_str,
-                                 const char *localaddr_str)
+                                 const char *localaddr_str,
+                                 Error **errp)
 {
     NetSocketState *s;
     int fd;
     struct sockaddr_in saddr;
     struct in_addr localaddr, *param_localaddr;
-    Error *err = NULL;
 
-    if (parse_host_port(&saddr, host_str, &err) < 0) {
-        error_report_err(err);
+    if (parse_host_port(&saddr, host_str, errp) < 0) {
         return -1;
     }
 
     if (localaddr_str != NULL) {
-        if (inet_aton(localaddr_str, &localaddr) == 0)
+        if (inet_aton(localaddr_str, &localaddr) == 0) {
+            error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
+                       localaddr_str);
             return -1;
+        }
         param_localaddr = &localaddr;
     } else {
         param_localaddr = NULL;
     }
 
-    fd = net_socket_mcast_create(&saddr, param_localaddr, &err);
+    fd = net_socket_mcast_create(&saddr, param_localaddr, errp);
     if (fd < 0) {
-        error_report_err(err);
         return -1;
     }
 
-    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
+    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
     if (!s) {
-        error_report_err(err);
         return -1;
     }
 
@@ -643,45 +641,45 @@ static int net_socket_udp_init(NetClientState *peer,
                                  const char *model,
                                  const char *name,
                                  const char *rhost,
-                                 const char *lhost)
+                                 const char *lhost,
+                                 Error **errp)
 {
     NetSocketState *s;
     int fd, ret;
     struct sockaddr_in laddr, raddr;
-    Error *err = NULL;
 
-    if (parse_host_port(&laddr, lhost, &err) < 0) {
-        error_report_err(err);
+    if (parse_host_port(&laddr, lhost, errp) < 0) {
         return -1;
     }
 
-    if (parse_host_port(&raddr, rhost, &err) < 0) {
-        error_report_err(err);
+    if (parse_host_port(&raddr, rhost, errp) < 0) {
         return -1;
     }
 
     fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
     if (fd < 0) {
-        perror("socket(PF_INET, SOCK_DGRAM)");
+        error_setg_errno(errp, errno, "failed to create datagram socket");
         return -1;
     }
 
     ret = socket_set_fast_reuse(fd);
     if (ret < 0) {
+        error_setg_errno(errp, errno, "set the socket 'SO_REUSEADDR'"
+                         " attribute failed");
         closesocket(fd);
         return -1;
     }
     ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
     if (ret < 0) {
-        perror("bind");
+        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
+                         inet_ntoa(laddr.sin_addr));
         closesocket(fd);
         return -1;
     }
     qemu_set_nonblock(fd);
 
-    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
+    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
     if (!s) {
-        error_report_err(err);
         return -1;
     }
 
@@ -696,8 +694,6 @@ static int net_socket_udp_init(NetClientState *peer,
 int net_init_socket(const Netdev *netdev, const char *name,
                     NetClientState *peer, Error **errp)
 {
-    /* FIXME error_setg(errp, ...) on failure */
-    Error *err = NULL;
     const NetdevSocketOptions *sock;
 
     assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
@@ -705,22 +701,21 @@ int net_init_socket(const Netdev *netdev, const char *name,
 
     if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
         sock->has_udp != 1) {
-        error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
+        error_setg(errp, "exactly one of fd=, listen=, connect=, mcast= or udp="
                      " is required");
         return -1;
     }
 
     if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
-        error_report("localaddr= is only valid with mcast= or udp=");
+        error_setg(errp, "localaddr= is only valid with mcast= or udp=");
         return -1;
     }
 
     if (sock->has_fd) {
         int fd;
 
-        fd = monitor_fd_param(cur_mon, sock->fd, &err);
+        fd = monitor_fd_param(cur_mon, sock->fd, errp);
         if (fd == -1) {
-            error_report_err(err);
             return -1;
         }
         qemu_set_nonblock(fd);
@@ -731,15 +726,16 @@ int net_init_socket(const Netdev *netdev, const char *name,
     }
 
     if (sock->has_listen) {
-        if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
+        if (net_socket_listen_init(peer, "socket", name,
+            sock->listen, errp) == -1) {
             return -1;
         }
         return 0;
     }
 
     if (sock->has_connect) {
-        if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
-            -1) {
+        if (net_socket_connect_init(peer, "socket", name,
+            sock->connect, errp) == -1) {
             return -1;
         }
         return 0;
@@ -748,8 +744,8 @@ int net_init_socket(const Netdev *netdev, const char *name,
     if (sock->has_mcast) {
         /* if sock->localaddr is missing, it has been initialized to "all bits
          * zero" */
-        if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
-            sock->localaddr) == -1) {
+        if (net_socket_mcast_init(peer, "socket", name,
+            sock->mcast, sock->localaddr, errp) == -1) {
             return -1;
         }
         return 0;
@@ -757,11 +753,11 @@ int net_init_socket(const Netdev *netdev, const char *name,
 
     assert(sock->has_udp);
     if (!sock->has_localaddr) {
-        error_report("localaddr= is mandatory with udp=");
+        error_setg(errp, "localaddr= is mandatory with udp=");
         return -1;
     }
-    if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
-        -1) {
+    if (net_socket_udp_init(peer, "socket", name,
+        sock->udp, sock->localaddr, errp) == -1) {
         return -1;
     }
     return 0;
-- 
2.9.4

Re: [Qemu-devel] [PATCH v6 1/4] net/socket: Don't treat odd socket type as SOCK_STREAM

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:08:47PM +0800, Mao Zhongyi wrote:
> In net_socket_fd_init(), the 'default' case is odd: it warns,
> then continues as if the socket type was SOCK_STREAM. The
> comment explains "this could be a eg. a pty", but that makes
> no sense. If @fd really was a pty, getsockopt() would fail
> with ENOTSOCK. If @fd was a socket, but neither SOCK_DGRAM nor
> SOCK_STREAM. It should not be treated as if it was SOCK_STREAM.
> 
> Turn this case into an Error. If there is a genuine reason to
> support something like SOCK_RAW, it should be explicitly
> handled.
> 
> Cc: jasowang@redhat.com
> Cc: armbru@redhat.com
> Cc: berrange@redhat.com
> Cc: armbru@redhat.com
> Suggested-by: Markus Armbruster <armbru@redhat.com>
> Suggested-by: Daniel P. Berrange <berrange@redhat.com>
> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> ---
>  net/socket.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/socket.c b/net/socket.c
> index dcae1ae..53765bd 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -449,9 +449,9 @@ static NetSocketState *net_socket_fd_init(NetClientState *peer,
>      case SOCK_STREAM:
>          return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
>      default:
> -        /* who knows ... this could be a eg. a pty, do warn and continue as stream */
> -        fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
> -        return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
> +        error_report("qemu: error: socket type=%d for fd=%d is not"
> +                " SOCK_DGRAM or SOCK_STREAM", so_type, fd);

Please drop the 'qemu: error: ' prefix on the message

Also, rather than 'is not' I suggest 'must be either'


> +        closesocket(fd);
>      }
>      return NULL;
>  }


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [Qemu-devel] [PATCH v6 2/4] net/socket: Convert several helper functions to Error

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:08:48PM +0800, Mao Zhongyi wrote:
> Currently, net_socket_mcast_create(), net_socket_fd_init_dgram() and
> net_socket_fd_init() use the function such as fprintf(), perror() to
> report an error message.
> 
> Now, convert these functions to Error.
> 
> Cc: jasowang@redhat.com
> Cc: armbru@redhat.com
> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
> ---
>  net/socket.c | 75 +++++++++++++++++++++++++++++++++++++-----------------------
>  1 file changed, 47 insertions(+), 28 deletions(-)

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:08:49PM +0800, Mao Zhongyi wrote:
> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
> index 5c326db..78e2b30 100644
> --- a/include/qemu/sockets.h
> +++ b/include/qemu/sockets.h

>          if (qemu_isdigit(buf[0])) {
> -            if (!inet_aton(buf, &saddr->sin_addr))
> +            if (!inet_aton(buf, &saddr->sin_addr)) {
> +                error_setg(errp, "host address '%s' is not a valid "
> +                           "IPv4 address", buf);
>                  return -1;
> +            }
>          } else {
> -            if ((he = gethostbyname(buf)) == NULL)
> +            he = gethostbyname(buf);
> +            if (he == NULL) {
> +                error_setg(errp, "can't resolve host address '%s': "
> +                           "unknown host", buf);
>                  return - 1;
> +            }

gethostbyname sets  'h_errno' on failure, so you should pass that
into error_setg_errno, instead of hardcoding 'unknown host' as a
message


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [Qemu-devel] [PATCH v6 4/4] net/socket: Improve -net socket error reporting

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:08:50PM +0800, Mao Zhongyi wrote:
> When -net socket fails, it first reports a specific error, then
> a generic one, like this:
> 
>     $ qemu-system-x86_64 -net socket,
>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
>     qemu-system-x86_64: -net socket: Device 'socket' could not be initialized

This second line of error message comes from net/net.c in the
net_client_init1 method:

        /* FIXME drop when all init functions store an Error */
        if (errp && !*errp) {
            error_setg(errp, QERR_DEVICE_INIT_FAILED,
                       NetClientDriver_lookup[netdev->type]);
        }


hopefully your patch could drop this code too ?

In fact this is the only use of QERR_DEVICE_INIT_FAILED in the
whole tree, so the QERR constant could possibly be killed too.


> 
> Convert net_socket_*_init() to Error to get rid of the superfluous second
> error message. After the patch, the effect like this:
> 
>     $ qemu-system-x86_64 -net socket,
>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
> 
> At the same time, add many explicit error handling message when it fails.
> 
> Cc: jasowang@redhat.com
> Cc: armbru@redhat.com
> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
> ---
>  net/socket.c | 92 +++++++++++++++++++++++++++++-------------------------------
>  1 file changed, 44 insertions(+), 48 deletions(-)
> 
> diff --git a/net/socket.c b/net/socket.c
> index 90dd4c0..47e6706 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -494,22 +494,21 @@ static void net_socket_accept(void *opaque)
>  static int net_socket_listen_init(NetClientState *peer,
>                                    const char *model,
>                                    const char *name,
> -                                  const char *host_str)
> +                                  const char *host_str,
> +                                  Error **errp)
>  {
>      NetClientState *nc;
>      NetSocketState *s;
>      struct sockaddr_in saddr;
>      int fd, ret;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>      if (fd < 0) {
> -        perror("socket");
> +        error_setg_errno(errp, errno, "failed to create stream socket");
>          return -1;
>      }
>      qemu_set_nonblock(fd);
> @@ -518,13 +517,14 @@ static int net_socket_listen_init(NetClientState *peer,
>  
>      ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
>      if (ret < 0) {
> -        perror("bind");
> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
> +                         inet_ntoa(saddr.sin_addr));
>          closesocket(fd);
>          return -1;
>      }
>      ret = listen(fd, 0);
>      if (ret < 0) {
> -        perror("listen");
> +        error_setg_errno(errp, errno, "listen socket failed");
>          closesocket(fd);
>          return -1;
>      }
> @@ -543,21 +543,20 @@ static int net_socket_listen_init(NetClientState *peer,
>  static int net_socket_connect_init(NetClientState *peer,
>                                     const char *model,
>                                     const char *name,
> -                                   const char *host_str)
> +                                   const char *host_str,
> +                                   Error **errp)
>  {
>      NetSocketState *s;
>      int fd, connected, ret;
>      struct sockaddr_in saddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>      if (fd < 0) {
> -        perror("socket");
> +        error_setg_errno(errp, errno, "failed to create stream socket");
>          return -1;
>      }
>      qemu_set_nonblock(fd);
> @@ -573,7 +572,7 @@ static int net_socket_connect_init(NetClientState *peer,
>                         errno == EINVAL) {
>                  break;
>              } else {
> -                perror("connect");
> +                error_setg_errno(errp, errno, "connection failed");
>                  closesocket(fd);
>                  return -1;
>              }
> @@ -582,9 +581,8 @@ static int net_socket_connect_init(NetClientState *peer,
>              break;
>          }
>      }
> -    s = net_socket_fd_init(peer, model, name, fd, connected, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, connected, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>      snprintf(s->nc.info_str, sizeof(s->nc.info_str),
> @@ -597,36 +595,36 @@ static int net_socket_mcast_init(NetClientState *peer,
>                                   const char *model,
>                                   const char *name,
>                                   const char *host_str,
> -                                 const char *localaddr_str)
> +                                 const char *localaddr_str,
> +                                 Error **errp)
>  {
>      NetSocketState *s;
>      int fd;
>      struct sockaddr_in saddr;
>      struct in_addr localaddr, *param_localaddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>          return -1;
>      }
>  
>      if (localaddr_str != NULL) {
> -        if (inet_aton(localaddr_str, &localaddr) == 0)
> +        if (inet_aton(localaddr_str, &localaddr) == 0) {
> +            error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
> +                       localaddr_str);
>              return -1;
> +        }
>          param_localaddr = &localaddr;
>      } else {
>          param_localaddr = NULL;
>      }
>  
> -    fd = net_socket_mcast_create(&saddr, param_localaddr, &err);
> +    fd = net_socket_mcast_create(&saddr, param_localaddr, errp);
>      if (fd < 0) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> @@ -643,45 +641,45 @@ static int net_socket_udp_init(NetClientState *peer,
>                                   const char *model,
>                                   const char *name,
>                                   const char *rhost,
> -                                 const char *lhost)
> +                                 const char *lhost,
> +                                 Error **errp)
>  {
>      NetSocketState *s;
>      int fd, ret;
>      struct sockaddr_in laddr, raddr;
> -    Error *err = NULL;
>  
> -    if (parse_host_port(&laddr, lhost, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&laddr, lhost, errp) < 0) {
>          return -1;
>      }
>  
> -    if (parse_host_port(&raddr, rhost, &err) < 0) {
> -        error_report_err(err);
> +    if (parse_host_port(&raddr, rhost, errp) < 0) {
>          return -1;
>      }
>  
>      fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
>      if (fd < 0) {
> -        perror("socket(PF_INET, SOCK_DGRAM)");
> +        error_setg_errno(errp, errno, "failed to create datagram socket");
>          return -1;
>      }
>  
>      ret = socket_set_fast_reuse(fd);
>      if (ret < 0) {
> +        error_setg_errno(errp, errno, "set the socket 'SO_REUSEADDR'"
> +                         " attribute failed");
>          closesocket(fd);
>          return -1;
>      }
>      ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
>      if (ret < 0) {
> -        perror("bind");
> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
> +                         inet_ntoa(laddr.sin_addr));
>          closesocket(fd);
>          return -1;
>      }
>      qemu_set_nonblock(fd);
>  
> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>      if (!s) {
> -        error_report_err(err);
>          return -1;
>      }
>  
> @@ -696,8 +694,6 @@ static int net_socket_udp_init(NetClientState *peer,
>  int net_init_socket(const Netdev *netdev, const char *name,
>                      NetClientState *peer, Error **errp)
>  {
> -    /* FIXME error_setg(errp, ...) on failure */
> -    Error *err = NULL;
>      const NetdevSocketOptions *sock;
>  
>      assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
> @@ -705,22 +701,21 @@ int net_init_socket(const Netdev *netdev, const char *name,
>  
>      if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
>          sock->has_udp != 1) {
> -        error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
> +        error_setg(errp, "exactly one of fd=, listen=, connect=, mcast= or udp="
>                       " is required");
>          return -1;
>      }
>  
>      if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
> -        error_report("localaddr= is only valid with mcast= or udp=");
> +        error_setg(errp, "localaddr= is only valid with mcast= or udp=");
>          return -1;
>      }
>  
>      if (sock->has_fd) {
>          int fd;
>  
> -        fd = monitor_fd_param(cur_mon, sock->fd, &err);
> +        fd = monitor_fd_param(cur_mon, sock->fd, errp);
>          if (fd == -1) {
> -            error_report_err(err);
>              return -1;
>          }
>          qemu_set_nonblock(fd);
> @@ -731,15 +726,16 @@ int net_init_socket(const Netdev *netdev, const char *name,
>      }
>  
>      if (sock->has_listen) {
> -        if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
> +        if (net_socket_listen_init(peer, "socket", name,
> +            sock->listen, errp) == -1) {
>              return -1;
>          }
>          return 0;
>      }
>  
>      if (sock->has_connect) {
> -        if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
> -            -1) {
> +        if (net_socket_connect_init(peer, "socket", name,
> +            sock->connect, errp) == -1) {
>              return -1;
>          }
>          return 0;
> @@ -748,8 +744,8 @@ int net_init_socket(const Netdev *netdev, const char *name,
>      if (sock->has_mcast) {
>          /* if sock->localaddr is missing, it has been initialized to "all bits
>           * zero" */
> -        if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
> -            sock->localaddr) == -1) {
> +        if (net_socket_mcast_init(peer, "socket", name,
> +            sock->mcast, sock->localaddr, errp) == -1) {
>              return -1;
>          }
>          return 0;
> @@ -757,11 +753,11 @@ int net_init_socket(const Netdev *netdev, const char *name,
>  
>      assert(sock->has_udp);
>      if (!sock->has_localaddr) {
> -        error_report("localaddr= is mandatory with udp=");
> +        error_setg(errp, "localaddr= is mandatory with udp=");
>          return -1;
>      }
> -    if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
> -        -1) {
> +    if (net_socket_udp_init(peer, "socket", name,
> +        sock->udp, sock->localaddr, errp) == -1) {
>          return -1;
>      }
>      return 0;
> -- 
> 2.9.4
> 
> 
> 
> 

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [Qemu-devel] [PATCH v6 1/4] net/socket: Don't treat odd socket type as SOCK_STREAM

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1524 bytes --]

On 06/28/2017 08:18 AM, Daniel P. Berrange wrote:
> On Wed, Jun 28, 2017 at 09:08:47PM +0800, Mao Zhongyi wrote:
>> In net_socket_fd_init(), the 'default' case is odd: it warns,
>> then continues as if the socket type was SOCK_STREAM. The
>> comment explains "this could be a eg. a pty", but that makes
>> no sense. If @fd really was a pty, getsockopt() would fail
>> with ENOTSOCK. If @fd was a socket, but neither SOCK_DGRAM nor
>> SOCK_STREAM. It should not be treated as if it was SOCK_STREAM.
>>
>> Turn this case into an Error. If there is a genuine reason to
>> support something like SOCK_RAW, it should be explicitly
>> handled.
>>

>>      default:
>> -        /* who knows ... this could be a eg. a pty, do warn and continue as stream */
>> -        fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
>> -        return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
>> +        error_report("qemu: error: socket type=%d for fd=%d is not"
>> +                " SOCK_DGRAM or SOCK_STREAM", so_type, fd);
> 
> Please drop the 'qemu: error: ' prefix on the message
> 
> Also, rather than 'is not' I suggest 'must be either'

Indentation is also off; we prefer that the second line starts right
after the ( of the first line, as in:

error_report("part 1"
             "part 2")


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

Re: [Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1374 bytes --]

On 06/28/2017 08:23 AM, Daniel P. Berrange wrote:
> On Wed, Jun 28, 2017 at 09:08:49PM +0800, Mao Zhongyi wrote:
>> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
>> index 5c326db..78e2b30 100644
>> --- a/include/qemu/sockets.h
>> +++ b/include/qemu/sockets.h
> 
>>          if (qemu_isdigit(buf[0])) {
>> -            if (!inet_aton(buf, &saddr->sin_addr))
>> +            if (!inet_aton(buf, &saddr->sin_addr)) {
>> +                error_setg(errp, "host address '%s' is not a valid "
>> +                           "IPv4 address", buf);
>>                  return -1;
>> +            }
>>          } else {
>> -            if ((he = gethostbyname(buf)) == NULL)
>> +            he = gethostbyname(buf);
>> +            if (he == NULL) {
>> +                error_setg(errp, "can't resolve host address '%s': "
>> +                           "unknown host", buf);
>>                  return - 1;
>> +            }
> 
> gethostbyname sets  'h_errno' on failure, so you should pass that
> into error_setg_errno, instead of hardcoding 'unknown host' as a
> message

'man gethostbyname' says it is deprecated, and that applications should
use getaddrinfo/getnameinfo instead.  What's our story here?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

Re: [Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Daniel P. Berrange]

On Wed, Jun 28, 2017 at 09:24:58AM -0500, Eric Blake wrote:
> On 06/28/2017 08:23 AM, Daniel P. Berrange wrote:
> > On Wed, Jun 28, 2017 at 09:08:49PM +0800, Mao Zhongyi wrote:
> >> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
> >> index 5c326db..78e2b30 100644
> >> --- a/include/qemu/sockets.h
> >> +++ b/include/qemu/sockets.h
> > 
> >>          if (qemu_isdigit(buf[0])) {
> >> -            if (!inet_aton(buf, &saddr->sin_addr))
> >> +            if (!inet_aton(buf, &saddr->sin_addr)) {
> >> +                error_setg(errp, "host address '%s' is not a valid "
> >> +                           "IPv4 address", buf);
> >>                  return -1;
> >> +            }
> >>          } else {
> >> -            if ((he = gethostbyname(buf)) == NULL)
> >> +            he = gethostbyname(buf);
> >> +            if (he == NULL) {
> >> +                error_setg(errp, "can't resolve host address '%s': "
> >> +                           "unknown host", buf);
> >>                  return - 1;
> >> +            }
> > 
> > gethostbyname sets  'h_errno' on failure, so you should pass that
> > into error_setg_errno, instead of hardcoding 'unknown host' as a
> > message
> 
> 'man gethostbyname' says it is deprecated, and that applications should
> use getaddrinfo/getnameinfo instead.  What's our story here?

The real story is to get net/socket.c converted to QIOChannelSocket
and kill this parse_host_port() method in sockets.c It is already
broken by design since it takes a 'struct sockdddr_in' and thus
can't do IPv6.

This patch doesn't make the existing situation worse, so I think
its fine to add this error reporting cleanup now, and not force
immediate conversion to QIOChannelSocket today.  The net/sockets.c
code needs a further refactor before that conversion can be done
in the right way - we've already reverted the wrong way twice ;-)

Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

Re: [Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Mao Zhongyi]

Hi, Daniel

On 06/28/2017 09:23 PM, Daniel P. Berrange wrote:
> On Wed, Jun 28, 2017 at 09:08:49PM +0800, Mao Zhongyi wrote:
>> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
>> index 5c326db..78e2b30 100644
>> --- a/include/qemu/sockets.h
>> +++ b/include/qemu/sockets.h
>
>>          if (qemu_isdigit(buf[0])) {
>> -            if (!inet_aton(buf, &saddr->sin_addr))
>> +            if (!inet_aton(buf, &saddr->sin_addr)) {
>> +                error_setg(errp, "host address '%s' is not a valid "
>> +                           "IPv4 address", buf);
>>                  return -1;
>> +            }
>>          } else {
>> -            if ((he = gethostbyname(buf)) == NULL)
>> +            he = gethostbyname(buf);
>> +            if (he == NULL) {
>> +                error_setg(errp, "can't resolve host address '%s': "
>> +                           "unknown host", buf);
>>                  return - 1;
>> +            }
>
> gethostbyname sets  'h_errno' on failure, so you should pass that
> into error_setg_errno, instead of hardcoding 'unknown host' as a
> message

Yes, 'h_errno' will be seted detailed error message when gethostbyname() failed,
but the value of 'h_errno', as far as I know, can be print by hstrerror(),
herror() and gai_strerror(). I'm not sure 'h_errno' can be parsed correctly
by error_setg_errno(), so I test it like this:

herror("----herror----");
error_report("----hstrerror----%s", hstrerror(h_errno));
error_report("----gai_strerror----%s", gai_strerror(h_errno));
error_setg_errno(errp, h_errno, "can't resolve host address '%s'" ,buf);


result:

----herror----: Unknown host
qemu-system-x86_64: -net socket,listen=hostname:: ----hstrerror----Unknown host
qemu-system-x86_64: -net socket,listen=hostname:: ----gai_strerror----Unknown error
qemu-system-x86_64: -net socket,listen=hostname:: can't resolve host address 'hostname': Operation not permitted


 From the results, obviously the error message is different.
error_setg_errno() prints a uncertain message like "Operation not
permitted", I think that the value of 'h_errno' is treated as a
standard error code for errno. Although they have the same value,
the information contained may not be same.

so is it really appropriate to pass 'h_errno' to error_setg_errno()?

Thanks,
Mao


> Regards,
> Daniel
>

Re: [Qemu-devel] [PATCH v6 4/4] net/socket: Improve -net socket error reporting

[Mao Zhongyi]

Hi, Daniel

On 06/28/2017 09:27 PM, Daniel P. Berrange wrote:
> On Wed, Jun 28, 2017 at 09:08:50PM +0800, Mao Zhongyi wrote:
>> When -net socket fails, it first reports a specific error, then
>> a generic one, like this:
>>
>>     $ qemu-system-x86_64 -net socket,
>>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
>>     qemu-system-x86_64: -net socket: Device 'socket' could not be initialized
>
> This second line of error message comes from net/net.c in the
> net_client_init1 method:
>
>         /* FIXME drop when all init functions store an Error */
>         if (errp && !*errp) {
>             error_setg(errp, QERR_DEVICE_INIT_FAILED,
>                        NetClientDriver_lookup[netdev->type]);
>         }
>
>
> hopefully your patch could drop this code too ?
>
> In fact this is the only use of QERR_DEVICE_INIT_FAILED in the
> whole tree, so the QERR constant could possibly be killed too.
>

OK, I will. :)

Thanks,
Mao

>
>>
>> Convert net_socket_*_init() to Error to get rid of the superfluous second
>> error message. After the patch, the effect like this:
>>
>>     $ qemu-system-x86_64 -net socket,
>>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
>>
>> At the same time, add many explicit error handling message when it fails.
>>
>> Cc: jasowang@redhat.com
>> Cc: armbru@redhat.com
>> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
>> ---
>>  net/socket.c | 92 +++++++++++++++++++++++++++++-------------------------------
>>  1 file changed, 44 insertions(+), 48 deletions(-)
>>
>> diff --git a/net/socket.c b/net/socket.c
>> index 90dd4c0..47e6706 100644
>> --- a/net/socket.c
>> +++ b/net/socket.c
>> @@ -494,22 +494,21 @@ static void net_socket_accept(void *opaque)
>>  static int net_socket_listen_init(NetClientState *peer,
>>                                    const char *model,
>>                                    const char *name,
>> -                                  const char *host_str)
>> +                                  const char *host_str,
>> +                                  Error **errp)
>>  {
>>      NetClientState *nc;
>>      NetSocketState *s;
>>      struct sockaddr_in saddr;
>>      int fd, ret;
>> -    Error *err = NULL;
>>
>> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
>> -        error_report_err(err);
>> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>>          return -1;
>>      }
>>
>>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>      if (fd < 0) {
>> -        perror("socket");
>> +        error_setg_errno(errp, errno, "failed to create stream socket");
>>          return -1;
>>      }
>>      qemu_set_nonblock(fd);
>> @@ -518,13 +517,14 @@ static int net_socket_listen_init(NetClientState *peer,
>>
>>      ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
>>      if (ret < 0) {
>> -        perror("bind");
>> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
>> +                         inet_ntoa(saddr.sin_addr));
>>          closesocket(fd);
>>          return -1;
>>      }
>>      ret = listen(fd, 0);
>>      if (ret < 0) {
>> -        perror("listen");
>> +        error_setg_errno(errp, errno, "listen socket failed");
>>          closesocket(fd);
>>          return -1;
>>      }
>> @@ -543,21 +543,20 @@ static int net_socket_listen_init(NetClientState *peer,
>>  static int net_socket_connect_init(NetClientState *peer,
>>                                     const char *model,
>>                                     const char *name,
>> -                                   const char *host_str)
>> +                                   const char *host_str,
>> +                                   Error **errp)
>>  {
>>      NetSocketState *s;
>>      int fd, connected, ret;
>>      struct sockaddr_in saddr;
>> -    Error *err = NULL;
>>
>> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
>> -        error_report_err(err);
>> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>>          return -1;
>>      }
>>
>>      fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>      if (fd < 0) {
>> -        perror("socket");
>> +        error_setg_errno(errp, errno, "failed to create stream socket");
>>          return -1;
>>      }
>>      qemu_set_nonblock(fd);
>> @@ -573,7 +572,7 @@ static int net_socket_connect_init(NetClientState *peer,
>>                         errno == EINVAL) {
>>                  break;
>>              } else {
>> -                perror("connect");
>> +                error_setg_errno(errp, errno, "connection failed");
>>                  closesocket(fd);
>>                  return -1;
>>              }
>> @@ -582,9 +581,8 @@ static int net_socket_connect_init(NetClientState *peer,
>>              break;
>>          }
>>      }
>> -    s = net_socket_fd_init(peer, model, name, fd, connected, &err);
>> +    s = net_socket_fd_init(peer, model, name, fd, connected, errp);
>>      if (!s) {
>> -        error_report_err(err);
>>          return -1;
>>      }
>>      snprintf(s->nc.info_str, sizeof(s->nc.info_str),
>> @@ -597,36 +595,36 @@ static int net_socket_mcast_init(NetClientState *peer,
>>                                   const char *model,
>>                                   const char *name,
>>                                   const char *host_str,
>> -                                 const char *localaddr_str)
>> +                                 const char *localaddr_str,
>> +                                 Error **errp)
>>  {
>>      NetSocketState *s;
>>      int fd;
>>      struct sockaddr_in saddr;
>>      struct in_addr localaddr, *param_localaddr;
>> -    Error *err = NULL;
>>
>> -    if (parse_host_port(&saddr, host_str, &err) < 0) {
>> -        error_report_err(err);
>> +    if (parse_host_port(&saddr, host_str, errp) < 0) {
>>          return -1;
>>      }
>>
>>      if (localaddr_str != NULL) {
>> -        if (inet_aton(localaddr_str, &localaddr) == 0)
>> +        if (inet_aton(localaddr_str, &localaddr) == 0) {
>> +            error_setg(errp, "localaddr '%s' is not a valid IPv4 address",
>> +                       localaddr_str);
>>              return -1;
>> +        }
>>          param_localaddr = &localaddr;
>>      } else {
>>          param_localaddr = NULL;
>>      }
>>
>> -    fd = net_socket_mcast_create(&saddr, param_localaddr, &err);
>> +    fd = net_socket_mcast_create(&saddr, param_localaddr, errp);
>>      if (fd < 0) {
>> -        error_report_err(err);
>>          return -1;
>>      }
>>
>> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
>> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>>      if (!s) {
>> -        error_report_err(err);
>>          return -1;
>>      }
>>
>> @@ -643,45 +641,45 @@ static int net_socket_udp_init(NetClientState *peer,
>>                                   const char *model,
>>                                   const char *name,
>>                                   const char *rhost,
>> -                                 const char *lhost)
>> +                                 const char *lhost,
>> +                                 Error **errp)
>>  {
>>      NetSocketState *s;
>>      int fd, ret;
>>      struct sockaddr_in laddr, raddr;
>> -    Error *err = NULL;
>>
>> -    if (parse_host_port(&laddr, lhost, &err) < 0) {
>> -        error_report_err(err);
>> +    if (parse_host_port(&laddr, lhost, errp) < 0) {
>>          return -1;
>>      }
>>
>> -    if (parse_host_port(&raddr, rhost, &err) < 0) {
>> -        error_report_err(err);
>> +    if (parse_host_port(&raddr, rhost, errp) < 0) {
>>          return -1;
>>      }
>>
>>      fd = qemu_socket(PF_INET, SOCK_DGRAM, 0);
>>      if (fd < 0) {
>> -        perror("socket(PF_INET, SOCK_DGRAM)");
>> +        error_setg_errno(errp, errno, "failed to create datagram socket");
>>          return -1;
>>      }
>>
>>      ret = socket_set_fast_reuse(fd);
>>      if (ret < 0) {
>> +        error_setg_errno(errp, errno, "set the socket 'SO_REUSEADDR'"
>> +                         " attribute failed");
>>          closesocket(fd);
>>          return -1;
>>      }
>>      ret = bind(fd, (struct sockaddr *)&laddr, sizeof(laddr));
>>      if (ret < 0) {
>> -        perror("bind");
>> +        error_setg_errno(errp, errno, "bind ip=%s to socket failed",
>> +                         inet_ntoa(laddr.sin_addr));
>>          closesocket(fd);
>>          return -1;
>>      }
>>      qemu_set_nonblock(fd);
>>
>> -    s = net_socket_fd_init(peer, model, name, fd, 0, &err);
>> +    s = net_socket_fd_init(peer, model, name, fd, 0, errp);
>>      if (!s) {
>> -        error_report_err(err);
>>          return -1;
>>      }
>>
>> @@ -696,8 +694,6 @@ static int net_socket_udp_init(NetClientState *peer,
>>  int net_init_socket(const Netdev *netdev, const char *name,
>>                      NetClientState *peer, Error **errp)
>>  {
>> -    /* FIXME error_setg(errp, ...) on failure */
>> -    Error *err = NULL;
>>      const NetdevSocketOptions *sock;
>>
>>      assert(netdev->type == NET_CLIENT_DRIVER_SOCKET);
>> @@ -705,22 +701,21 @@ int net_init_socket(const Netdev *netdev, const char *name,
>>
>>      if (sock->has_fd + sock->has_listen + sock->has_connect + sock->has_mcast +
>>          sock->has_udp != 1) {
>> -        error_report("exactly one of fd=, listen=, connect=, mcast= or udp="
>> +        error_setg(errp, "exactly one of fd=, listen=, connect=, mcast= or udp="
>>                       " is required");
>>          return -1;
>>      }
>>
>>      if (sock->has_localaddr && !sock->has_mcast && !sock->has_udp) {
>> -        error_report("localaddr= is only valid with mcast= or udp=");
>> +        error_setg(errp, "localaddr= is only valid with mcast= or udp=");
>>          return -1;
>>      }
>>
>>      if (sock->has_fd) {
>>          int fd;
>>
>> -        fd = monitor_fd_param(cur_mon, sock->fd, &err);
>> +        fd = monitor_fd_param(cur_mon, sock->fd, errp);
>>          if (fd == -1) {
>> -            error_report_err(err);
>>              return -1;
>>          }
>>          qemu_set_nonblock(fd);
>> @@ -731,15 +726,16 @@ int net_init_socket(const Netdev *netdev, const char *name,
>>      }
>>
>>      if (sock->has_listen) {
>> -        if (net_socket_listen_init(peer, "socket", name, sock->listen) == -1) {
>> +        if (net_socket_listen_init(peer, "socket", name,
>> +            sock->listen, errp) == -1) {
>>              return -1;
>>          }
>>          return 0;
>>      }
>>
>>      if (sock->has_connect) {
>> -        if (net_socket_connect_init(peer, "socket", name, sock->connect) ==
>> -            -1) {
>> +        if (net_socket_connect_init(peer, "socket", name,
>> +            sock->connect, errp) == -1) {
>>              return -1;
>>          }
>>          return 0;
>> @@ -748,8 +744,8 @@ int net_init_socket(const Netdev *netdev, const char *name,
>>      if (sock->has_mcast) {
>>          /* if sock->localaddr is missing, it has been initialized to "all bits
>>           * zero" */
>> -        if (net_socket_mcast_init(peer, "socket", name, sock->mcast,
>> -            sock->localaddr) == -1) {
>> +        if (net_socket_mcast_init(peer, "socket", name,
>> +            sock->mcast, sock->localaddr, errp) == -1) {
>>              return -1;
>>          }
>>          return 0;
>> @@ -757,11 +753,11 @@ int net_init_socket(const Netdev *netdev, const char *name,
>>
>>      assert(sock->has_udp);
>>      if (!sock->has_localaddr) {
>> -        error_report("localaddr= is mandatory with udp=");
>> +        error_setg(errp, "localaddr= is mandatory with udp=");
>>          return -1;
>>      }
>> -    if (net_socket_udp_init(peer, "socket", name, sock->udp, sock->localaddr) ==
>> -        -1) {
>> +    if (net_socket_udp_init(peer, "socket", name,
>> +        sock->udp, sock->localaddr, errp) == -1) {
>>          return -1;
>>      }
>>      return 0;
>> --
>> 2.9.4
>>
>>
>>
>>
>
> Regards,
> Daniel
>

Re: [Qemu-devel] [PATCH v6 1/4] net/socket: Don't treat odd socket type as SOCK_STREAM

[Mao Zhongyi]

Hi, Eric

On 06/28/2017 10:23 PM, Eric Blake wrote:
> On 06/28/2017 08:18 AM, Daniel P. Berrange wrote:
>> On Wed, Jun 28, 2017 at 09:08:47PM +0800, Mao Zhongyi wrote:
>>> In net_socket_fd_init(), the 'default' case is odd: it warns,
>>> then continues as if the socket type was SOCK_STREAM. The
>>> comment explains "this could be a eg. a pty", but that makes
>>> no sense. If @fd really was a pty, getsockopt() would fail
>>> with ENOTSOCK. If @fd was a socket, but neither SOCK_DGRAM nor
>>> SOCK_STREAM. It should not be treated as if it was SOCK_STREAM.
>>>
>>> Turn this case into an Error. If there is a genuine reason to
>>> support something like SOCK_RAW, it should be explicitly
>>> handled.
>>>
>
>>>      default:
>>> -        /* who knows ... this could be a eg. a pty, do warn and continue as stream */
>>> -        fprintf(stderr, "qemu: warning: socket type=%d for fd=%d is not SOCK_DGRAM or SOCK_STREAM\n", so_type, fd);
>>> -        return net_socket_fd_init_stream(peer, model, name, fd, is_connected);
>>> +        error_report("qemu: error: socket type=%d for fd=%d is not"
>>> +                " SOCK_DGRAM or SOCK_STREAM", so_type, fd);
>>
>> Please drop the 'qemu: error: ' prefix on the message
>>
>> Also, rather than 'is not' I suggest 'must be either'
>
> Indentation is also off; we prefer that the second line starts right
> after the ( of the first line, as in:
>
> error_report("part 1"
>              "part 2")

OK, I will. :)

Thanks,
Mao

>
>

Re: [Qemu-devel] [PATCH v6 3/4] net/net: Convert parse_host_port() to Error

[Markus Armbruster]

"Daniel P. Berrange" <berrange@redhat.com> writes:

> On Wed, Jun 28, 2017 at 09:24:58AM -0500, Eric Blake wrote:
>> On 06/28/2017 08:23 AM, Daniel P. Berrange wrote:
>> > On Wed, Jun 28, 2017 at 09:08:49PM +0800, Mao Zhongyi wrote:
>> >> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
>> >> index 5c326db..78e2b30 100644
>> >> --- a/include/qemu/sockets.h
>> >> +++ b/include/qemu/sockets.h
>> > 
>> >>          if (qemu_isdigit(buf[0])) {
>> >> -            if (!inet_aton(buf, &saddr->sin_addr))
>> >> +            if (!inet_aton(buf, &saddr->sin_addr)) {
>> >> +                error_setg(errp, "host address '%s' is not a valid "
>> >> +                           "IPv4 address", buf);
>> >>                  return -1;
>> >> +            }
>> >>          } else {
>> >> -            if ((he = gethostbyname(buf)) == NULL)
>> >> +            he = gethostbyname(buf);
>> >> +            if (he == NULL) {
>> >> +                error_setg(errp, "can't resolve host address '%s': "
>> >> +                           "unknown host", buf);
>> >>                  return - 1;
>> >> +            }
>> > 
>> > gethostbyname sets  'h_errno' on failure, so you should pass that
>> > into error_setg_errno, instead of hardcoding 'unknown host' as a
>> > message

'unknown host' is misleading when h_errno != HOST_NOT_FOUND.

>> 'man gethostbyname' says it is deprecated, and that applications should
>> use getaddrinfo/getnameinfo instead.  What's our story here?
>
> The real story is to get net/socket.c converted to QIOChannelSocket
> and kill this parse_host_port() method in sockets.c It is already
> broken by design since it takes a 'struct sockdddr_in' and thus
> can't do IPv6.
>
> This patch doesn't make the existing situation worse, so I think
> its fine to add this error reporting cleanup now, and not force
> immediate conversion to QIOChannelSocket today.  The net/sockets.c
> code needs a further refactor before that conversion can be done
> in the right way - we've already reverted the wrong way twice ;-)

Until then, let's go with a generic error message, as I requested in my
review of v5.  Just drop the misleading ": unknown host" part.

Re: [Qemu-devel] [PATCH v6 4/4] net/socket: Improve -net socket error reporting

[Markus Armbruster]

Mao Zhongyi <maozy.fnst@cn.fujitsu.com> writes:

> Hi, Daniel
>
> On 06/28/2017 09:27 PM, Daniel P. Berrange wrote:
>> On Wed, Jun 28, 2017 at 09:08:50PM +0800, Mao Zhongyi wrote:
>>> When -net socket fails, it first reports a specific error, then
>>> a generic one, like this:
>>>
>>>     $ qemu-system-x86_64 -net socket,
>>>     qemu-system-x86_64: -net socket: exactly one of fd=, listen=, connect=, mcast= or udp= is required
>>>     qemu-system-x86_64: -net socket: Device 'socket' could not be initialized
>>
>> This second line of error message comes from net/net.c in the
>> net_client_init1 method:
>>
>>         /* FIXME drop when all init functions store an Error */
>>         if (errp && !*errp) {
>>             error_setg(errp, QERR_DEVICE_INIT_FAILED,
>>                        NetClientDriver_lookup[netdev->type]);
>>         }
>>
>>
>> hopefully your patch could drop this code too ?
>>
>> In fact this is the only use of QERR_DEVICE_INIT_FAILED in the
>> whole tree, so the QERR constant could possibly be killed too.
>>
>
> OK, I will. :)

You can do that only when *all* init functions stor an Error!  We're not
there, yet:

    $ grep 'FIXME error_setg' net/*
    net/l2tpv3.c:    /* FIXME error_setg(errp, ...) on failure */
    net/slirp.c:    /* FIXME error_setg(errp, ...) on failure */
    net/socket.c:    /* FIXME error_setg(errp, ...) on failure */
    net/tap-win32.c:    /* FIXME error_setg(errp, ...) on failure */
    net/vde.c:    /* FIXME error_setg(errp, ...) on failure */