tests/qtest: Move mkimg() and have_qemu_img() from libqos to libqtest

These two functions can be useful for other qtests beside the
qos-test, too, so move them to libqtest instead.

Message-Id: <20230704071655.75381-3-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/qtest/libqtest.c

@@ -1742,3 +1742,55 @@ bool qtest_qom_get_bool(QTestState *s, const char *path, const char *property)
 
     return b;
 }
+
+bool have_qemu_img(void)
+{
+    char *rpath;
+    const char *path = getenv("QTEST_QEMU_IMG");
+    if (!path) {
+        return false;
+    }
+
+    rpath = realpath(path, NULL);
+    if (!rpath) {
+        return false;
+    } else {
+        free(rpath);
+        return true;
+    }
+}
+
+bool mkimg(const char *file, const char *fmt, unsigned size_mb)
+{
+    gchar *cli;
+    bool ret;
+    int rc;
+    GError *err = NULL;
+    char *qemu_img_path;
+    gchar *out, *out2;
+    char *qemu_img_abs_path;
+
+    qemu_img_path = getenv("QTEST_QEMU_IMG");
+    if (!qemu_img_path) {
+        return false;
+    }
+    qemu_img_abs_path = realpath(qemu_img_path, NULL);
+    if (!qemu_img_abs_path) {
+        return false;
+    }
+
+    cli = g_strdup_printf("%s create -f %s %s %uM", qemu_img_abs_path,
+                          fmt, file, size_mb);
+    ret = g_spawn_command_line_sync(cli, &out, &out2, &rc, &err);
+    if (err || !g_spawn_check_exit_status(rc, &err)) {
+        fprintf(stderr, "%s\n", err->message);
+        g_error_free(err);
+    }
+
+    g_free(out);
+    g_free(out2);
+    g_free(cli);
+    free(qemu_img_abs_path);
+
+    return ret && !err;
+}