dracut-install: Support the compressed firmware files correctly

The compressed firmware support was supposed to be already
implemented, but it didn't work as expected in the end, because dracut
moved to use dracut-install binary.  This patch adds the support of
XZ-compressed firmware installation to dracut-install for fixing the
missing piece.

At best the firmware files should be uncompressed in initrd, but this
patch simply copies the compressed file as-is, as a quick workaround.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1146769
Signed-off-by: Takashi Iwai <tiwai@suse.de>

install/dracut-install.c

@@ -1151,6 +1151,8 @@ static int install_firmware(struct kmod_module *mod)
                 ret = -1;
                 STRV_FOREACH(q, firmwaredirs) {
                         _cleanup_free_ char *fwpath = NULL;
+                        _cleanup_free_ char *fwpath_xz = NULL;
+                        const char *fw;
                         struct stat sb;
                         int r;
 
@@ -1160,12 +1162,21 @@ static int install_firmware(struct kmod_module *mod)
                                 exit(EXIT_FAILURE);
                         }
 
+                        fw = fwpath;
                         if (stat(fwpath, &sb) != 0) {
-                                log_debug("stat(%s) != 0", fwpath);
-                                continue;
+                                r = asprintf(&fwpath_xz, "%s.xz", fwpath);
+                                if (r < 0) {
+                                        log_error("Out of memory!");
+                                        exit(EXIT_FAILURE);
+                                }
+                                if (stat(fwpath_xz, &sb) != 0) {
+                                        log_debug("stat(%s) != 0", fwpath);
+                                        continue;
+                                }
+                                fw = fwpath_xz;
                         }
 
-                        ret = dracut_install(fwpath, fwpath, false, false, true);
+                        ret = dracut_install(fw, fw, false, false, true);
                         if (ret == 0)
                                 log_debug("dracut_install '%s' OK", fwpath);
                 }