inspect: recognize the Void Linux distribution

Since Void Linux provides only an /etc/os-release with no VERSION_ID
field, then special-case it to avoid that the os-release parsing ignore
it.

This provides basic distro identification, and icon.

generator/actions.ml

@@ -1183,6 +1183,10 @@ Ubuntu.
 
 The distro could not be determined.
 
+=item \"voidlinux\"
+
+Void Linux.
+
 =item \"windows\"
 
 Windows does not have distributions.  This string is

inspector/virt-inspector.rng

@@ -108,6 +108,7 @@
         <value>suse-based</value>
         <value>ttylinux</value>
         <value>ubuntu</value>
+        <value>voidlinux</value>
         <value>windows</value>
         <!-- "unknown" is intentionally left out -->
       </choice>

src/guestfs-internal.h

@@ -569,6 +569,7 @@ enum inspect_os_distro {
   OS_DISTRO_ALTLINUX,
   OS_DISTRO_FRUGALWARE,
   OS_DISTRO_PLD_LINUX,
+  OS_DISTRO_VOID_LINUX,
 };
 
 enum inspect_os_package_format {

src/inspect-fs-unix.c

@@ -216,6 +216,8 @@ parse_os_release (guestfs_h *g, struct inspect_fs *fs, const char *filename)
         distro = OS_DISTRO_SLES;
       else if (VALUE_IS ("ubuntu"))
         distro = OS_DISTRO_UBUNTU;
+      else if (VALUE_IS ("void"))
+        distro = OS_DISTRO_VOID_LINUX;
     } else if (STRPREFIX (line, "PRETTY_NAME=")) {
       free (product_name);
       product_name = safe_strndup (g, value, value_len);
@@ -229,10 +231,18 @@ parse_os_release (guestfs_h *g, struct inspect_fs *fs, const char *filename)
   }
 
   /* If we haven't got all the fields, exit right away. */
-  if (distro == OS_DISTRO_UNKNOWN || product_name == NULL ||
-      version.v_major == -1 || version.v_minor == -1)
+  if (distro == OS_DISTRO_UNKNOWN || product_name == NULL)
     return 0;
 
+  if (version.v_major == -1 || version.v_minor == -1) {
+    /* Void Linux has no VERSION_ID (yet), but since it's a rolling
+     * distro and has no other version/release-like file. */
+    if (distro == OS_DISTRO_VOID_LINUX)
+      version_init_null (&version);
+    else
+      return 0;
+  }
+
   /* Apparently, os-release in Debian and CentOS does not provide the full
    * version number in VERSION_ID, but just the "major" part of it.
    * Hence, if version.v_minor is 0, act as there was no information in

src/inspect-fs.c

@@ -499,6 +499,7 @@ guestfs_int_check_package_format (guestfs_h *g, struct inspect_fs *fs)
   case OS_DISTRO_OPENBSD:
   case OS_DISTRO_FRUGALWARE:
   case OS_DISTRO_PLD_LINUX:
+  case OS_DISTRO_VOID_LINUX:
   case OS_DISTRO_UNKNOWN:
     fs->package_format = OS_PACKAGE_FORMAT_UNKNOWN;
     break;
@@ -583,6 +584,7 @@ guestfs_int_check_package_management (guestfs_h *g, struct inspect_fs *fs)
   case OS_DISTRO_OPENBSD:
   case OS_DISTRO_FRUGALWARE:
   case OS_DISTRO_PLD_LINUX:
+  case OS_DISTRO_VOID_LINUX:
   case OS_DISTRO_UNKNOWN:
     fs->package_management = OS_PACKAGE_MANAGEMENT_UNKNOWN;
     break;

src/inspect-icon.c

@@ -61,6 +61,7 @@ static char *icon_opensuse (guestfs_h *g, struct inspect_fs *fs, size_t *size_r)
 #if CAN_DO_CIRROS
 static char *icon_cirros (guestfs_h *g, struct inspect_fs *fs, size_t *size_r);
 #endif
+static char *icon_voidlinux (guestfs_h *g, struct inspect_fs *fs, size_t *size_r);
 #if CAN_DO_WINDOWS
 static char *icon_windows (guestfs_h *g, struct inspect_fs *fs, size_t *size_r);
 #endif
@@ -158,6 +159,10 @@ guestfs_impl_inspect_get_icon (guestfs_h *g, const char *root, size_t *size_r,
 #endif
       break;
 
+    case OS_DISTRO_VOID_LINUX:
+      r = icon_voidlinux (g, fs, &size);
+      break;
+
       /* These are just to keep gcc warnings happy. */
     case OS_DISTRO_ARCHLINUX:
     case OS_DISTRO_BUILDROOT:
@@ -420,6 +425,14 @@ icon_cirros (guestfs_h *g, struct inspect_fs *fs, size_t *size_r)
 
 #endif /* CAN_DO_CIRROS */
 
+#define VOIDLINUX_ICON "/usr/share/void-artwork/void-logo.png"
+
+static char *
+icon_voidlinux (guestfs_h *g, struct inspect_fs *fs, size_t *size_r)
+{
+  return get_png (g, fs, VOIDLINUX_ICON, size_r, 20480);
+}
+
 #if CAN_DO_WINDOWS
 
 /* Windows, as usual, has to be much more complicated and stupid than

src/inspect.c

@@ -291,6 +291,7 @@ guestfs_impl_inspect_get_distro (guestfs_h *g, const char *root)
   case OS_DISTRO_TTYLINUX: ret = safe_strdup (g, "ttylinux"); break;
   case OS_DISTRO_WINDOWS: ret = safe_strdup (g, "windows"); break;
   case OS_DISTRO_UBUNTU: ret = safe_strdup (g, "ubuntu"); break;
+  case OS_DISTRO_VOID_LINUX: ret = safe_strdup (g, "voidlinux"); break;
   case OS_DISTRO_UNKNOWN: ret = safe_strdup (g, "unknown"); break;
   }