virstat: fix signature of virstat helper

In preparation to the code move to virnetdevtap.c, this change:

* renames virNetInterfaceStats to virNetDevTapInterfaceStats
* changes 'path' to 'ifname', to use the same vocable as other
  method in virnetdevtap.c.
* Add the attributes checker

src/libvirt_private.syms

@@ -2397,7 +2397,7 @@ virSocketAddrSetIPv6AddrNetOrder;
 virSocketAddrSetPort;
 
 # util/virstats.h
-virNetInterfaceStats;
+virNetDevTapInterfaceStats;
 
 # util/virstorageencryption.h
 virStorageEncryptionFormat;

src/libxl/libxl_driver.c

@@ -4985,7 +4985,7 @@ libxlDomainInterfaceStats(virDomainPtr dom,
     }
 
     if (ret == 0)
-        ret = virNetInterfaceStats(path, stats);
+        ret = virNetDevTapInterfaceStats(path, stats);
     else
         virReportError(VIR_ERR_INVALID_ARG,
                        _("'%s' is not a known interface"), path);

src/lxc/lxc_driver.c

@@ -2896,7 +2896,7 @@ lxcDomainInterfaceStats(virDomainPtr dom,
     }
 
     if (ret == 0)
-        ret = virNetInterfaceStats(path, stats);
+        ret = virNetDevTapInterfaceStats(path, stats);
     else
         virReportError(VIR_ERR_INVALID_ARG,
                        _("Invalid path, '%s' is not a known interface"), path);

src/openvz/openvz_driver.c

@@ -2027,7 +2027,7 @@ openvzDomainInterfaceStats(virDomainPtr dom,
     }
 
     if (ret == 0)
-        ret = virNetInterfaceStats(path, stats);
+        ret = virNetDevTapInterfaceStats(path, stats);
     else
         virReportError(VIR_ERR_INVALID_ARG,
                        _("invalid path, '%s' is not a known interface"), path);

src/qemu/qemu_driver.c

@@ -11009,7 +11009,7 @@ qemuDomainInterfaceStats(virDomainPtr dom,
         if (virNetDevOpenvswitchInterfaceStats(path, stats) < 0)
             goto cleanup;
     } else {
-        if (virNetInterfaceStats(path, stats) < 0)
+        if (virNetDevTapInterfaceStats(path, stats) < 0)
             goto cleanup;
     }
 
@@ -19204,7 +19204,7 @@ qemuDomainGetStatsInterface(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
                 continue;
             }
         } else {
-            if (virNetInterfaceStats(dom->def->nets[i]->ifname, &tmp) < 0) {
+            if (virNetDevTapInterfaceStats(dom->def->nets[i]->ifname, &tmp) < 0) {
                 virResetLastError();
                 continue;
             }

src/util/virstats.c

@@ -50,10 +50,10 @@
  */
 #ifdef __linux__
 int
-virNetInterfaceStats(const char *path,
+virNetDevTapInterfaceStats(const char *ifname,
                            virDomainInterfaceStatsPtr stats)
 {
-    int path_len;
+    int ifname_len;
     FILE *fp;
     char line[256], *colon;
 
@@ -64,7 +64,7 @@ virNetInterfaceStats(const char *path,
         return -1;
     }
 
-    path_len = strlen(path);
+    ifname_len = strlen(ifname);
 
     while (fgets(line, sizeof(line), fp)) {
         long long dummy;
@@ -84,8 +84,8 @@ virNetInterfaceStats(const char *path,
         colon = strchr(line, ':');
         if (!colon) continue;
         *colon = '\0';
-        if (colon-path_len >= line &&
+        if (colon - ifname_len >= line &&
-            STREQ(colon-path_len, path)) {
+            STREQ(colon - ifname_len, ifname)) {
             /* IMPORTANT NOTE!
              * /proc/net/dev vif<domid>.nn sees the network from the point
              * of view of dom0 / hypervisor.  So bytes TRANSMITTED by dom0
@@ -121,7 +121,7 @@ virNetInterfaceStats(const char *path,
 }
 #elif defined(HAVE_GETIFADDRS) && defined(AF_LINK)
 int
-virNetInterfaceStats(const char *path,
+virNetDevTapInterfaceStats(const char *ifname,
                            virDomainInterfaceStatsPtr stats)
 {
     struct ifaddrs *ifap, *ifa;
@@ -138,7 +138,7 @@ virNetInterfaceStats(const char *path,
         if (ifa->ifa_addr->sa_family != AF_LINK)
             continue;
 
-        if (STREQ(ifa->ifa_name, path)) {
+        if (STREQ(ifa->ifa_name, ifname)) {
             ifd = (struct if_data *)ifa->ifa_data;
             stats->tx_bytes = ifd->ifi_ibytes;
             stats->tx_packets = ifd->ifi_ipackets;
@@ -167,7 +167,7 @@ virNetInterfaceStats(const char *path,
 }
 #else
 int
-virNetInterfaceStats(const char *path ATTRIBUTE_UNUSED,
+virNetDevTapInterfaceStats(const char *ifname ATTRIBUTE_UNUSED,
                            virDomainInterfaceStatsPtr stats ATTRIBUTE_UNUSED)
 {
     virReportError(VIR_ERR_OPERATION_INVALID, "%s",

src/util/virstats.h

@@ -25,7 +25,8 @@
 
 # include "internal.h"
 
-int virNetInterfaceStats(const char *path,
+int virNetDevTapInterfaceStats(const char *ifname,
-                         virDomainInterfaceStatsPtr stats);
+                               virDomainInterfaceStatsPtr stats)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
 
 #endif /* __STATS_LINUX_H__ */

src/xen/xen_hypervisor.c

@@ -1466,7 +1466,7 @@ xenHypervisorDomainInterfaceStats(virDomainDefPtr def,
         return -1;
     }
 
-    return virNetInterfaceStats(path, stats);
+    return virNetDevTapInterfaceStats(path, stats);
 #else
     virReportError(VIR_ERR_OPERATION_INVALID, "%s",
                    _("/proc/net/dev: Interface not found"));