net: Improve parameter error reporting

As host network devices can also be instantiated via the monitor, errors
should then be reported to the related monitor instead of stderr. This
requires larger refactoring, so this patch starts small with introducing
a helper to catch both cases and convert net_client_init as well as
net_slirp_redir.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>

1 files changed, 69 insertions, 62 deletions

diff --git a/net.c b/net.c
index 2594ed7..7f7616b 100644
--- a/net.c
+++ b/net.c
@@ -532,6 +532,21 @@ ssize_t qemu_sendv_packet(VLANClientState *sender, const struct iovec *iov,
     return max_len;
 }
 
+static void config_error(Monitor *mon, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    if (mon) {
+        monitor_vprintf(mon, fmt, ap);
+    } else {
+        fprintf(stderr, "qemu: ");
+        vfprintf(stderr, fmt, ap);
+        exit(1);
+    }
+    va_end(ap);
+}
+
 #if defined(CONFIG_SLIRP)
 
 /* slirp network adapter */
@@ -674,7 +689,7 @@ void net_slirp_redir(Monitor *mon, const char *redir_str, const char *redir_opt2
 {
     int is_udp;
     char buf[256], *r;
-    const char *p, *errmsg;
+    const char *p;
     struct in_addr guest_addr;
     int host_port, guest_port;
 
@@ -723,20 +738,12 @@ void net_slirp_redir(Monitor *mon, const char *redir_str, const char *redir_opt2
         goto fail_syntax;
 
     if (slirp_redir(is_udp, host_port, guest_addr, guest_port) < 0) {
-        errmsg = "could not set up redirection\n";
-        goto fail;
+        config_error(mon, "could not set up redirection '%s'\n", redir_str);
     }
     return;
 
  fail_syntax:
-    errmsg = "invalid redirection format\n";
- fail:
-    if (mon) {
-        monitor_printf(mon, "%s", errmsg);
-    } else {
-        fprintf(stderr, "qemu: %s", errmsg);
-        exit(1);
-    }
+    config_error(mon, "invalid redirection format '%s'\n", redir_str);
 }
 
 #ifndef _WIN32
@@ -1784,7 +1791,7 @@ static void net_dump_cleanup(VLANClientState *vc)
     qemu_free(s);
 }
 
-static int net_dump_init(VLANState *vlan, const char *device,
+static int net_dump_init(Monitor *mon, VLANState *vlan, const char *device,
                          const char *name, const char *filename, int len)
 {
     struct pcap_file_hdr hdr;
@@ -1794,7 +1801,7 @@ static int net_dump_init(VLANState *vlan, const char *device,
 
     s->fd = open(filename, O_CREAT | O_WRONLY, 0644);
     if (s->fd < 0) {
-        fprintf(stderr, "-net dump: can't open %s\n", filename);
+        config_error(mon, "-net dump: can't open %s\n", filename);
         return -1;
     }
 
@@ -1809,7 +1816,7 @@ static int net_dump_init(VLANState *vlan, const char *device,
     hdr.linktype = 1;
 
     if (write(s->fd, &hdr, sizeof(hdr)) < sizeof(hdr)) {
-        perror("-net dump write error");
+        config_error(mon, "-net dump write error: %s\n", strerror(errno));
         close(s->fd);
         qemu_free(s);
         return -1;
@@ -1884,7 +1891,7 @@ void qemu_check_nic_model_list(NICInfo *nd, const char * const *models,
     exit(exit_status);
 }
 
-int net_client_init(const char *device, const char *p)
+int net_client_init(Monitor *mon, const char *device, const char *p)
 {
     static const char * const fd_params[] = {
         "vlan", "name", "fd", NULL
@@ -1901,7 +1908,7 @@ int net_client_init(const char *device, const char *p)
     vlan = qemu_find_vlan(vlan_id);
 
     if (get_param_value(buf, sizeof(buf), "name", p)) {
-        name = strdup(buf);
+        name = qemu_strdup(buf);
     }
     if (!strcmp(device, "nic")) {
         static const char * const nic_params[] = {
@@ -1912,12 +1919,12 @@ int net_client_init(const char *device, const char *p)
         int idx = nic_get_free_idx();
 
         if (check_params(buf, sizeof(buf), nic_params, p) < 0) {
-            fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                    buf, p);
-            return -1;
+            config_error(mon, "invalid parameter '%s' in '%s'\n", buf, p);
+            ret = -1;
+            goto out;
         }
         if (idx == -1 || nb_nics >= MAX_NICS) {
-            fprintf(stderr, "Too Many NICs\n");
+            config_error(mon, "Too Many NICs\n");
             ret = -1;
             goto out;
         }
@@ -1932,7 +1939,7 @@ int net_client_init(const char *device, const char *p)
 
         if (get_param_value(buf, sizeof(buf), "macaddr", p)) {
             if (parse_macaddr(macaddr, buf) < 0) {
-                fprintf(stderr, "invalid syntax for ethernet address\n");
+                config_error(mon, "invalid syntax for ethernet address\n");
                 ret = -1;
                 goto out;
             }
@@ -1950,8 +1957,9 @@ int net_client_init(const char *device, const char *p)
     } else
     if (!strcmp(device, "none")) {
         if (*p != '\0') {
-            fprintf(stderr, "qemu: 'none' takes no parameters\n");
-            return -1;
+            config_error(mon, "'none' takes no parameters\n");
+            ret = -1;
+            goto out;
         }
         /* does nothing. It is needed to signal that no network cards
            are wanted */
@@ -1963,9 +1971,9 @@ int net_client_init(const char *device, const char *p)
             "vlan", "name", "hostname", "restrict", "ip", NULL
         };
         if (check_params(buf, sizeof(buf), slirp_params, p) < 0) {
-            fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                    buf, p);
-            return -1;
+            config_error(mon, "invalid parameter '%s' in '%s'\n", buf, p);
+            ret = -1;
+            goto out;
         }
         if (get_param_value(buf, sizeof(buf), "hostname", p)) {
             pstrcpy(slirp_hostname, sizeof(slirp_hostname), buf);
@@ -1986,7 +1994,7 @@ int net_client_init(const char *device, const char *p)
         port = strtol(p, &devname, 10);
         devname++;
         if (port < 1 || port > 65535) {
-            fprintf(stderr, "vmchannel wrong port number\n");
+            config_error(mon, "vmchannel wrong port number\n");
             ret = -1;
             goto out;
         }
@@ -1994,8 +2002,8 @@ int net_client_init(const char *device, const char *p)
         snprintf(name, 20, "vmchannel%ld", port);
         vmc->hd = qemu_chr_open(name, devname, NULL);
         if (!vmc->hd) {
-            fprintf(stderr, "qemu: could not open vmchannel device"
-                    "'%s'\n", devname);
+            config_error(mon, "could not open vmchannel device '%s'\n",
+                         devname);
             ret = -1;
             goto out;
         }
@@ -2014,12 +2022,12 @@ int net_client_init(const char *device, const char *p)
         char ifname[64];
 
         if (check_params(buf, sizeof(buf), tap_params, p) < 0) {
-            fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                    buf, p);
-            return -1;
+            config_error(mon, "invalid parameter '%s' in '%s'\n", buf, p);
+            ret = -1;
+            goto out;
         }
         if (get_param_value(ifname, sizeof(ifname), "ifname", p) <= 0) {
-            fprintf(stderr, "tap: no interface name\n");
+            config_error(mon, "tap: no interface name\n");
             ret = -1;
             goto out;
         }
@@ -2035,9 +2043,9 @@ int net_client_init(const char *device, const char *p)
         vlan->nb_host_devs++;
         if (get_param_value(buf, sizeof(buf), "fd", p) > 0) {
             if (check_params(chkbuf, sizeof(chkbuf), fd_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             fd = strtol(buf, NULL, 0);
             fcntl(fd, F_SETFL, O_NONBLOCK);
@@ -2048,9 +2056,9 @@ int net_client_init(const char *device, const char *p)
                 "vlan", "name", "ifname", "script", "downscript", NULL
             };
             if (check_params(chkbuf, sizeof(chkbuf), tap_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             if (get_param_value(ifname, sizeof(ifname), "ifname", p) <= 0) {
                 ifname[0] = '\0';
@@ -2070,9 +2078,9 @@ int net_client_init(const char *device, const char *p)
         if (get_param_value(buf, sizeof(buf), "fd", p) > 0) {
             int fd;
             if (check_params(chkbuf, sizeof(chkbuf), fd_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             fd = strtol(buf, NULL, 0);
             ret = -1;
@@ -2083,9 +2091,9 @@ int net_client_init(const char *device, const char *p)
                 "vlan", "name", "listen", NULL
             };
             if (check_params(chkbuf, sizeof(chkbuf), listen_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             ret = net_socket_listen_init(vlan, device, name, buf);
         } else if (get_param_value(buf, sizeof(buf), "connect", p) > 0) {
@@ -2093,9 +2101,9 @@ int net_client_init(const char *device, const char *p)
                 "vlan", "name", "connect", NULL
             };
             if (check_params(chkbuf, sizeof(chkbuf), connect_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             ret = net_socket_connect_init(vlan, device, name, buf);
         } else if (get_param_value(buf, sizeof(buf), "mcast", p) > 0) {
@@ -2103,13 +2111,13 @@ int net_client_init(const char *device, const char *p)
                 "vlan", "name", "mcast", NULL
             };
             if (check_params(chkbuf, sizeof(chkbuf), mcast_params, p) < 0) {
-                fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                        chkbuf, p);
-                return -1;
+                config_error(mon, "invalid parameter '%s' in '%s'\n", chkbuf, p);
+                ret = -1;
+                goto out;
             }
             ret = net_socket_mcast_init(vlan, device, name, buf);
         } else {
-            fprintf(stderr, "Unknown socket options: %s\n", p);
+            config_error(mon, "Unknown socket options: %s\n", p);
             ret = -1;
             goto out;
         }
@@ -2124,9 +2132,9 @@ int net_client_init(const char *device, const char *p)
 	int vde_port, vde_mode;
 
         if (check_params(buf, sizeof(buf), vde_params, p) < 0) {
-            fprintf(stderr, "qemu: invalid parameter '%s' in '%s'\n",
-                    buf, p);
-            return -1;
+            config_error(mon, "invalid parameter '%s' in '%s'\n", buf, p);
+            ret = -1;
+            goto out;
         }
         vlan->nb_host_devs++;
         if (get_param_value(vde_sock, sizeof(vde_sock), "sock", p) <= 0) {
@@ -2157,18 +2165,17 @@ int net_client_init(const char *device, const char *p)
         if (!get_param_value(buf, sizeof(buf), "file", p)) {
             snprintf(buf, sizeof(buf), "qemu-vlan%d.pcap", vlan_id);
         }
-        ret = net_dump_init(vlan, device, name, buf, len);
+        ret = net_dump_init(mon, vlan, device, name, buf, len);
     } else {
-        fprintf(stderr, "Unknown network device: %s\n", device);
+        config_error(mon, "Unknown network device: %s\n", device);
         ret = -1;
         goto out;
     }
     if (ret < 0) {
-        fprintf(stderr, "Could not initialize device '%s'\n", device);
+        config_error(mon, "Could not initialize device '%s'\n", device);
     }
 out:
-    if (name)
-        free(name);
+    qemu_free(name);
     return ret;
 }
 
@@ -2206,7 +2213,7 @@ void net_host_device_add(Monitor *mon, const char *device, const char *opts)
         monitor_printf(mon, "invalid host network device %s\n", device);
         return;
     }
-    if (net_client_init(device, opts ? opts : "") < 0) {
+    if (net_client_init(mon, device, opts ? opts : "") < 0) {
         monitor_printf(mon, "adding host network device %s failed\n", device);
     }
 }
@@ -2252,7 +2259,7 @@ int net_client_parse(const char *str)
     if (*p == ',')
         p++;
 
-    return net_client_init(device, p);
+    return net_client_init(NULL, device, p);
 }
 
 void do_info_network(Monitor *mon)