qdev: Improve diagnostics for bad property values

Property "vlan" reports "failed to parse" even when the value parses
just fine, but the result doesn't name an existing VLAN.

Similarly, properties "drive", "chr" and "netdev" misleadingly report
"failed to parse" when the value doesn't name an existing host device.

Change PropertyInfo method parse to return an error code, so that
qdev_prop_parse() can report the error more accurately.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/qdev-properties.c

@@ -44,7 +44,7 @@ static int parse_bit(DeviceState *dev, Property *prop, const char *str)
     else if (!strncasecmp(str, "off", 3))
         bit_prop_set(dev, prop, false);
     else
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -72,7 +72,7 @@ static int parse_uint8(DeviceState *dev, Property *prop, const char *str)
     /* accept both hex and decimal */
     fmt = strncasecmp(str, "0x",2) == 0 ? "%" PRIx8 : "%" PRIu8;
     if (sscanf(str, fmt, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -100,7 +100,7 @@ static int parse_uint16(DeviceState *dev, Property *prop, const char *str)
     /* accept both hex and decimal */
     fmt = strncasecmp(str, "0x",2) == 0 ? "%" PRIx16 : "%" PRIu16;
     if (sscanf(str, fmt, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -128,7 +128,7 @@ static int parse_uint32(DeviceState *dev, Property *prop, const char *str)
     /* accept both hex and decimal */
     fmt = strncasecmp(str, "0x",2) == 0 ? "%" PRIx32 : "%" PRIu32;
     if (sscanf(str, fmt, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -151,7 +151,7 @@ static int parse_int32(DeviceState *dev, Property *prop, const char *str)
     int32_t *ptr = qdev_get_prop_ptr(dev, prop);
 
     if (sscanf(str, "%" PRId32, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -176,7 +176,7 @@ static int parse_hex32(DeviceState *dev, Property *prop, const char *str)
     uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
 
     if (sscanf(str, "%" PRIx32, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -204,7 +204,7 @@ static int parse_uint64(DeviceState *dev, Property *prop, const char *str)
     /* accept both hex and decimal */
     fmt = strncasecmp(str, "0x",2) == 0 ? "%" PRIx64 : "%" PRIu64;
     if (sscanf(str, fmt, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -229,7 +229,7 @@ static int parse_hex64(DeviceState *dev, Property *prop, const char *str)
     uint64_t *ptr = qdev_get_prop_ptr(dev, prop);
 
     if (sscanf(str, "%" PRIx64, ptr) != 1)
-        return -1;
+        return -EINVAL;
     return 0;
 }
 
@@ -283,7 +283,7 @@ static int parse_drive(DeviceState *dev, Property *prop, const char *str)
 
     *ptr = drive_get_by_id(str);
     if (*ptr == NULL)
-        return -1;
+        return -ENOENT;
     return 0;
 }
 
@@ -309,7 +309,7 @@ static int parse_chr(DeviceState *dev, Property *prop, const char *str)
 
     *ptr = qemu_chr_find(str);
     if (*ptr == NULL)
-        return -1;
+        return -ENOENT;
     return 0;
 }
 
@@ -340,7 +340,7 @@ static int parse_netdev(DeviceState *dev, Property *prop, const char *str)
 
     *ptr = qemu_find_netdev(str);
     if (*ptr == NULL)
-        return -1;
+        return -ENOENT;
     return 0;
 }
 
@@ -371,10 +371,10 @@ static int parse_vlan(DeviceState *dev, Property *prop, const char *str)
     int id;
 
     if (sscanf(str, "%d", &id) != 1)
-        return -1;
+        return -EINVAL;
     *ptr = qemu_find_vlan(id, 1);
     if (*ptr == NULL)
-        return -1;
+        return -ENOENT;
     return 0;
 }
 
@@ -427,15 +427,15 @@ static int parse_mac(DeviceState *dev, Property *prop, const char *str)
 
     for (i = 0, pos = 0; i < 6; i++, pos += 3) {
         if (!qemu_isxdigit(str[pos]))
-            return -1;
+            return -EINVAL;
         if (!qemu_isxdigit(str[pos+1]))
-            return -1;
+            return -EINVAL;
         if (i == 5) {
             if (str[pos+2] != '\0')
-                return -1;
+                return -EINVAL;
         } else {
             if (str[pos+2] != ':' && str[pos+2] != '-')
-                return -1;
+                return -EINVAL;
         }
         mac->a[i] = strtol(str+pos, &p, 16);
     }
@@ -472,13 +472,13 @@ static int parse_pci_devfn(DeviceState *dev, Property *prop, const char *str)
     if (sscanf(str, "%x.%x%n", &slot, &fn, &n) != 2) {
         fn = 0;
         if (sscanf(str, "%x%n", &slot, &n) != 1) {
-            return -1;
+            return -EINVAL;
         }
     }
     if (str[n] != '\0')
-        return -1;
+        return -EINVAL;
     if (fn > 7)
-        return -1;
+        return -EINVAL;
     *ptr = slot << 3 | fn;
     return 0;
 }
@@ -541,6 +541,7 @@ int qdev_prop_exists(DeviceState *dev, const char *name)
 int qdev_prop_parse(DeviceState *dev, const char *name, const char *value)
 {
     Property *prop;
+    int ret;
 
     prop = qdev_prop_find(dev, name);
     if (!prop) {
@@ -553,9 +554,19 @@ int qdev_prop_parse(DeviceState *dev, const char *name, const char *value)
                 dev->info->name, name);
         return -1;
     }
-    if (prop->info->parse(dev, prop, value) != 0) {
-        fprintf(stderr, "property \"%s.%s\": failed to parse \"%s\"\n",
-                dev->info->name, name, value);
+    ret = prop->info->parse(dev, prop, value);
+    if (ret < 0) {
+        switch (ret) {
+        default:
+        case -EINVAL:
+            fprintf(stderr, "property \"%s.%s\": failed to parse \"%s\"\n",
+                    dev->info->name, name, value);
+            break;
+        case -ENOENT:
+            fprintf(stderr, "property \"%s.%s\": could not find \"%s\"\n",
+                    dev->info->name, name, value);
+            break;
+        }
         return -1;
     }
     return 0;