libxl: a couple of MAC address patches

diff -r 6a40e32738e7 -r b85fcaaf73a9 tools/libxl/libxl_internal.c
@@ -277,6 +277,23 @@ int libxl__file_reference_unmap(libxl_fi
 	return ERROR_FAIL;
 }
 
+_hidden int libxl__parse_mac(const char *s, libxl_mac mac)
+{
+    const char *tok;
+    char *endptr;
+    int i;
+
+    for (i = 0, tok = s; *tok && (i < 6); ++i, tok += 3) {
+        mac[i] = strtol(tok, &endptr, 16);
+        if (endptr != (tok + 2) || (*endptr != '\0' && *endptr != ':') )
+            return ERROR_INVAL;
+    }
+    if ( i != 6 )
+        return ERROR_INVAL;
+
+    return 0;
+}
+
 int libxl__fd_set_cloexec(int fd)
 {
     int flags = 0;

diff -r 6a40e32738e7 -r b85fcaaf73a9 tools/libxl/libxl_internal.h
@@ -426,6 +426,8 @@ _hidden int libxl__fd_set_cloexec(int fd
 
 _hidden int libxl__e820_alloc(libxl__gc *gc, uint32_t domid, libxl_domain_config *d_config);
 
+_hidden int libxl__parse_mac(const char *s, libxl_mac mac);
+
 #define STRINGIFY(x) #x
 #define TOSTRING(x) STRINGIFY(x)
 

diff -r 6a40e32738e7 -r b85fcaaf73a9 tools/libxl/libxl_utils.c
@@ -452,22 +452,19 @@ int libxl_mac_to_device_nic(libxl_ctx *c
                             const char *mac, libxl_device_nic *nic)
 {
     libxl_nicinfo *nics;
-    unsigned int nb, i;
+    unsigned int nb, rc, i;
     int found;
-    uint8_t mac_n[6];
+    libxl_mac mac_n;
     uint8_t *a, *b;
-    const char *tok;
-    char *endptr;
+
+    rc = libxl__parse_mac(mac, mac_n);
+    if (rc)
+	    return rc;
 
     nics = libxl_list_nics(ctx, domid, &nb);
     if (!nics)
         return ERROR_FAIL;
 
-    for (i = 0, tok = mac; *tok && (i < 6); ++i, tok += 3) {
-        mac_n[i] = strtol(tok, &endptr, 16);
-        if (endptr != (tok + 2))
-            return ERROR_INVAL;
-    }
     memset(nic, 0, sizeof (libxl_device_nic));
     found = 0;
     for (i = 0; i < nb; ++i) {

@@ -494,9 +491,8 @@ int libxl_devid_to_device_nic(libxl_ctx 
                               const char *devid, libxl_device_nic *nic)
 {
     libxl__gc gc = LIBXL_INIT_GC(ctx);
-    char *tok, *val;
+    char *val;
     char *dompath, *nic_path_fe, *nic_path_be;
-    unsigned int i;
     int rc = ERROR_FAIL;
 
     memset(nic, 0, sizeof (libxl_device_nic));

@@ -515,10 +511,10 @@ int libxl_devid_to_device_nic(libxl_ctx 
     nic->devid = strtoul(devid, NULL, 10);
 
     val = libxl__xs_read(&gc, XBT_NULL, libxl__sprintf(&gc, "%s/mac", nic_path_fe));
-    for (i = 0, tok = strtok(val, ":"); tok && (i < 6);
-         ++i, tok = strtok(NULL, ":")) {
-        nic->mac[i] = strtoul(tok, NULL, 16);
-    }
+    rc = libxl__parse_mac(val, nic->mac);
+    if (rc)
+	    goto out;
+
     nic->script = xs_read(ctx->xsh, XBT_NULL, libxl__sprintf(&gc, "%s/script", nic_path_be), NULL);
     rc = 0;
 out:

diff -r b85fcaaf73a9 -r 88486538d739 tools/libxl/libxl_internal.c
@@ -294,6 +294,18 @@ _hidden int libxl__parse_mac(const char 
     return 0;
 }
 
+_hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b)
+{
+    int i;
+
+    for (i = 0; i<6; i++) {
+        if ((*a)[i] != (*b)[i])
+            return (*a)[i] - (*b)[i];
+    }
+
+    return 0;
+}
+
 int libxl__fd_set_cloexec(int fd)
 {
     int flags = 0;

diff -r b85fcaaf73a9 -r 88486538d739 tools/libxl/libxl_internal.h
@@ -426,7 +426,10 @@ _hidden int libxl__fd_set_cloexec(int fd
 
 _hidden int libxl__e820_alloc(libxl__gc *gc, uint32_t domid, libxl_domain_config *d_config);
 
+/* parse the string @s as a sequence of 6 colon separated bytes in to @mac */
 _hidden int libxl__parse_mac(const char *s, libxl_mac mac);
+/* compare mac address @a and @b. 0 if the same, -ve if a<b and +ve if a>b */
+_hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b);
 
 #define STRINGIFY(x) #x
 #define TOSTRING(x) STRINGIFY(x)

diff -r b85fcaaf73a9 -r 88486538d739 tools/libxl/libxl_utils.c
@@ -453,9 +453,7 @@ int libxl_mac_to_device_nic(libxl_ctx *c
 {
     libxl_nicinfo *nics;
     unsigned int nb, rc, i;
-    int found;
     libxl_mac mac_n;
-    uint8_t *a, *b;
 
     rc = libxl__parse_mac(mac, mac_n);
     if (rc)

@@ -466,17 +464,15 @@ int libxl_mac_to_device_nic(libxl_ctx *c
         return ERROR_FAIL;
 
     memset(nic, 0, sizeof (libxl_device_nic));
-    found = 0;
+
+    rc = ERROR_INVAL;
     for (i = 0; i < nb; ++i) {
-        for (i = 0, a = nics[i].mac, b = mac_n;
-             (b < mac_n + 6) && (*a == *b); ++a, ++b)
-            ;
-        if ((b >= mac_n + 6) && (*a == *b)) {
+        if (!libxl__compare_macs(&mac_n, &nics[i].mac)) {
             nic->backend_domid = nics[i].backend_id;
             nic->devid = nics[i].devid;
             memcpy(nic->mac, nics[i].mac, sizeof (nic->mac));
             nic->script = strdup(nics[i].script);
-            found = 1;
+            rc = 0;
             break;
         }
     }

@@ -484,7 +480,7 @@ int libxl_mac_to_device_nic(libxl_ctx *c
     for (i=0; i<nb; i++)
         libxl_nicinfo_destroy(&nics[i]);
     free(nics);
-    return found;
+    return rc;
 }
 
 int libxl_devid_to_device_nic(libxl_ctx *ctx, uint32_t domid,