Merge pull request #1091 from vojtechtrefny/master_lvm-config-get

lvm: Add support for reading lvm.conf

docs/libblockdev-sections.txt

@@ -388,6 +388,7 @@ bd_lvm_set_devices_filter
 bd_lvm_writecache_attach
 bd_lvm_writecache_create_cached_lv
 bd_lvm_writecache_detach
+bd_lvm_config_get
 BDLVMTech
 BDLVMTechMode
 bd_lvm_is_tech_avail

src/lib/plugin_apis/lvm.api

@@ -737,6 +737,7 @@ typedef enum {
     BD_LVM_TECH_WRITECACHE,
     BD_LVM_TECH_DEVICES,
     BD_LVM_TECH_SHARED,
+    BD_LVM_TECH_CONFIG,
 } BDLVMTech;
 
 typedef enum {
@@ -2026,4 +2027,21 @@ gboolean bd_lvm_devices_add (const gchar *device, const gchar *devices_file, con
  */
 gboolean bd_lvm_devices_delete (const gchar *device, const gchar *devices_file, const BDExtraArg **extra, GError **error);
 
+/**
+ * bd_lvm_config_get:
+ * @section: (nullable): LVM config section, e.g. 'global' or %NULL to print the entire config
+ * @setting: (nullable): name of the specific setting, e.g. 'umask' or %NULL to print the entire @section
+ * @type: type of the config, e.g. 'full' or 'current'
+ * @values_only: whether to include only values without keys in the output
+ * @global_config: whether to include our internal global config in the call or not
+ * @extra: (nullable) (array zero-terminated=1): extra options for the lvmconfig command
+ *                                               (just passed to LVM as is)
+ * @error: (out) (optional): place to store error (if any)
+ *
+ * Returns: (transfer full): Requested LVM config @section and @setting configuration or %NULL in case of error.
+ *
+ * Tech category: %BD_LVM_TECH_CONFIG no mode (it is ignored)
+ */
+gchar* bd_lvm_config_get (const gchar *section, const gchar *setting, const gchar *type, gboolean values_only, gboolean global_config, const BDExtraArg **extra, GError **error);
+
 #endif  /* BD_LVM_API */

src/plugins/lvm-dbus.c

@@ -293,11 +293,14 @@ static GMutex deps_check_lock;
 #define DEPS_LVM_MASK (1 << DEPS_LVM)
 #define DEPS_LVMDEVICES 1
 #define DEPS_LVMDEVICES_MASK (1 << DEPS_LVMDEVICES)
-#define DEPS_LAST 2
+#define DEPS_LVMCONFIG 2
+#define DEPS_LVMCONFIG_MASK (1 << DEPS_LVMCONFIG)
+#define DEPS_LAST 3
 
 static const UtilDep deps[DEPS_LAST] = {
     {"lvm", LVM_MIN_VERSION, "version", "LVM version:\\s+([\\d\\.]+)"},
     {"lvmdevices", NULL, NULL, NULL},
+    {"lvmconfig", NULL, NULL, NULL},
 };
 
 #define DBUS_DEPS_LVMDBUSD 0
@@ -415,6 +418,8 @@ gboolean bd_lvm_is_tech_avail (BDLVMTech tech, guint64 mode, GError **error) {
                check_features (&avail_features, FEATURES_WRITECACHE_MASK, features, FEATURES_LAST, &deps_check_lock, error);
     case BD_LVM_TECH_DEVICES:
         return check_deps (&avail_deps, DEPS_LVMDEVICES_MASK, deps, DEPS_LAST, &deps_check_lock, error);
+    case BD_LVM_TECH_CONFIG:
+        return check_deps (&avail_deps, DEPS_LVMCONFIG_MASK, deps, DEPS_LAST, &deps_check_lock, error);
     default:
         /* everything is supported by this implementation of the plugin */
         return check_dbus_deps (&avail_dbus_deps, DBUS_DEPS_LVMDBUSD_MASK, dbus_deps, DBUS_DEPS_LAST, &deps_check_lock, error);
@@ -4917,3 +4922,58 @@ gboolean bd_lvm_devices_delete (const gchar *device, const gchar *devices_file,
 
     return bd_utils_exec_and_report_error (args, extra, error);
 }
+
+/**
+ * bd_lvm_config_get:
+ * @section: (nullable): LVM config section, e.g. 'global' or %NULL to print the entire config
+ * @setting: (nullable): name of the specific setting, e.g. 'umask' or %NULL to print the entire @section
+ * @type: type of the config, e.g. 'full' or 'current'
+ * @values_only: whether to include only values without keys in the output
+ * @global_config: whether to include our internal global config in the call or not
+ * @extra: (nullable) (array zero-terminated=1): extra options for the lvmconfig command
+ *                                               (just passed to LVM as is)
+ * @error: (out) (optional): place to store error (if any)
+ *
+ * Returns: Requested LVM config @section and @setting configuration or %NULL in case of error.
+ *
+ * Tech category: (transfer full): %BD_LVM_TECH_CONFIG no mode (it is ignored)
+ */
+gchar* bd_lvm_config_get (const gchar *section, const gchar *setting, const gchar *type, gboolean values_only, gboolean global_config, const BDExtraArg **extra, GError **error) {
+    g_autofree gchar *conf_spec = NULL;
+    g_autofree gchar *config_arg = NULL;
+    const gchar *args[7] = {"lvmconfig", "--typeconfig", NULL, NULL, NULL, NULL, NULL};
+    guint next_arg = 2;
+    gchar *output = NULL;
+    gboolean success = FALSE;
+
+    if (!section && setting) {
+        g_set_error (error, BD_LVM_ERROR, BD_LVM_ERROR_FAIL,
+                     "Specifying setting without section is not supported.");
+        return NULL;
+    }
+
+    if (section)
+        if (setting)
+            conf_spec = g_strdup_printf ("%s/%s", section, setting);
+        else
+            conf_spec = g_strdup (section);
+    else
+        conf_spec = NULL;
+
+    args[next_arg++] = type;
+    args[next_arg++] = conf_spec;
+    if (values_only)
+        args[next_arg++] = "--valuesonly";
+
+    g_mutex_lock (&global_config_lock);
+    if (global_config && global_config_str) {
+        config_arg = g_strdup_printf ("--config=%s", global_config_str);
+        args[next_arg++] = config_arg;
+    }
+    g_mutex_unlock (&global_config_lock);
+
+    success = bd_utils_exec_and_capture_output (args, extra, &output, error);
+    if (!success)
+        return NULL;
+    return g_strchomp (output);
+}

src/plugins/lvm.c

@@ -3970,3 +3970,58 @@ gboolean bd_lvm_devices_delete (const gchar *device, const gchar *devices_file,
 
     return bd_utils_exec_and_report_error (args, extra, error);
 }
+
+/**
+ * bd_lvm_config_get:
+ * @section: (nullable): LVM config section, e.g. 'global' or %NULL to print the entire config
+ * @setting: (nullable): name of the specific setting, e.g. 'umask' or %NULL to print the entire @section
+ * @type: type of the config, e.g. 'full' or 'current'
+ * @values_only: whether to include only values without keys in the output
+ * @global_config: whether to include our internal global config in the call or not
+ * @extra: (nullable) (array zero-terminated=1): extra options for the lvmconfig command
+ *                                               (just passed to LVM as is)
+ * @error: (out) (optional): place to store error (if any)
+ *
+ * Returns: (transfer full): Requested LVM config @section and @setting configuration or %NULL in case of error.
+ *
+ * Tech category: %BD_LVM_TECH_CONFIG no mode (it is ignored)
+ */
+gchar* bd_lvm_config_get (const gchar *section, const gchar *setting, const gchar *type, gboolean values_only, gboolean global_config, const BDExtraArg **extra, GError **error) {
+    g_autofree gchar *conf_spec = NULL;
+    g_autofree gchar *config_arg = NULL;
+    const gchar *args[7] = {"lvmconfig", "--typeconfig", NULL, NULL, NULL, NULL, NULL};
+    guint next_arg = 2;
+    gchar *output = NULL;
+    gboolean success = FALSE;
+
+    if (!section && setting) {
+        g_set_error (error, BD_LVM_ERROR, BD_LVM_ERROR_FAIL,
+                     "Specifying setting without section is not supported.");
+        return NULL;
+    }
+
+    if (section)
+        if (setting)
+            conf_spec = g_strdup_printf ("%s/%s", section, setting);
+        else
+            conf_spec = g_strdup (section);
+    else
+        conf_spec = NULL;
+
+    args[next_arg++] = type;
+    args[next_arg++] = conf_spec;
+    if (values_only)
+        args[next_arg++] = "--valuesonly";
+
+    g_mutex_lock (&global_config_lock);
+    if (global_config && global_config_str) {
+        config_arg = g_strdup_printf ("--config=%s", global_config_str);
+        args[next_arg++] = config_arg;
+    }
+    g_mutex_unlock (&global_config_lock);
+
+    success = bd_utils_exec_and_capture_output (args, extra, &output, error);
+    if (!success)
+        return NULL;
+    return g_strchomp (output);
+}

src/plugins/lvm.h

@@ -201,6 +201,7 @@ typedef enum {
     BD_LVM_TECH_WRITECACHE,
     BD_LVM_TECH_DEVICES,
     BD_LVM_TECH_SHARED,
+    BD_LVM_TECH_CONFIG,
 } BDLVMTech;
 
 typedef enum {
@@ -330,4 +331,6 @@ GHashTable* bd_lvm_vdo_get_stats_full (const gchar *vg_name, const gchar *pool_n
 gboolean bd_lvm_devices_add (const gchar *device, const gchar *devices_file, const BDExtraArg **extra, GError **error);
 gboolean bd_lvm_devices_delete (const gchar *device, const gchar *devices_file, const BDExtraArg **extra, GError **error);
 
+gchar* bd_lvm_config_get (const gchar *section, const gchar *setting, const gchar *type, gboolean values_only, gboolean global_config, const BDExtraArg **extra, GError **error);
+
 #endif /* BD_LVM */

src/python/gi/overrides/BlockDev.py

@@ -1016,6 +1016,13 @@ def lvm_devices_delete(device, devices_file=None, extra=None, **kwargs):
     return _lvm_devices_delete(device, devices_file, extra)
 __all__.append("lvm_devices_delete")
 
+_lvm_config_get = BlockDev.lvm_config_get
+@override(BlockDev.lvm_config_get)
+def lvm_config_get(section=None, setting=None, type="full", values_only=True, global_config=True, extra=None, **kwargs):
+    extra = _get_extra(extra, kwargs)
+    return _lvm_config_get(section, setting, type, values_only, global_config, extra)
+__all__.append("lvm_config_get")
+
 
 _md_get_superblock_size = BlockDev.md_get_superblock_size
 @override(BlockDev.md_get_superblock_size)

tests/lvm_dbus_tests.py

@@ -83,6 +83,7 @@ def setUpClass(cls):
     def tearDownClass(cls):
         # reset back to default
         BlockDev.utils_set_log_level(BlockDev.UTILS_LOG_WARNING)
+        BlockDev.lvm_set_global_config(None)
 
         super(LvmNoDevTestCase, cls).tearDownClass()
 
@@ -338,6 +339,52 @@ def test_cache_mode_bijection(self):
         with self.assertRaises(GLib.GError):
             BlockDev.lvm_cache_get_mode_from_str("bla")
 
+    @tag_test(TestTags.NOSTORAGE)
+    def test_lvm_config(self):
+        """Verify that we can correctly read from LVM config"""
+
+        # should be always available, "lvmconfig" command is just alias for "lvm config"
+        succ = BlockDev.lvm_is_tech_avail(BlockDev.LVMTech.CONFIG, 0)
+        self.assertTrue(succ)
+
+        with self.assertRaises(GLib.GError):
+            BlockDev.lvm_config_get(None, "dir")
+
+        # get entire config
+        conf = BlockDev.lvm_config_get()
+        self.assertTrue(conf)
+        self.assertTrue(conf.startswith("config"))
+
+        # get just the "devices" section
+        conf = BlockDev.lvm_config_get("devices")
+        self.assertTrue(conf)
+        self.assertTrue(conf.startswith("devices"))
+
+        # let's be brave and assume devices/dir is set everywhere ti /dev
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full", values_only=False)
+        self.assertEqual(devdir, "dir=\"/dev\"")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "default")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        # let's try to override some results with --config
+        BlockDev.lvm_set_global_config("devices/dir=/test")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full")
+        self.assertEqual(devdir, "\"/test\"")
+
+        # "default" config should not be affected by --config
+        devdir = BlockDev.lvm_config_get("devices", "dir", "default")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        # disable global config
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full", global_config=False)
+        self.assertEqual(devdir, "\"/dev\"")
+
+
 @unittest.skipUnless(lvm_dbus_running, "LVM DBus not running")
 class LvmPVonlyTestCase(LVMTestCase):
 

tests/lvm_test.py

@@ -82,6 +82,7 @@ def setUpClass(cls):
     def tearDownClass(cls):
         # reset back to default
         BlockDev.utils_set_log_level(BlockDev.UTILS_LOG_WARNING)
+        BlockDev.lvm_set_global_config(None)
 
         super(LvmNoDevTestCase, cls).tearDownClass()
 
@@ -332,6 +333,48 @@ def test_cache_mode_bijection(self):
         with self.assertRaises(GLib.GError):
             BlockDev.lvm_cache_get_mode_from_str("bla")
 
+    @tag_test(TestTags.NOSTORAGE)
+    def test_lvm_config(self):
+        """Verify that we can correctly read from LVM config"""
+
+        with self.assertRaises(GLib.GError):
+            BlockDev.lvm_config_get(None, "dir")
+
+        # get entire config
+        conf = BlockDev.lvm_config_get()
+        self.assertTrue(conf)
+        self.assertTrue(conf.startswith("config"))
+
+        # get just the "devices" section
+        conf = BlockDev.lvm_config_get("devices")
+        self.assertTrue(conf)
+        self.assertTrue(conf.startswith("devices"))
+
+        # let's be brave and assume devices/dir is set everywhere ti /dev
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full", values_only=False)
+        self.assertEqual(devdir, "dir=\"/dev\"")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "default")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        # let's try to override some results with --config
+        BlockDev.lvm_set_global_config("devices/dir=/test")
+
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full")
+        self.assertEqual(devdir, "\"/test\"")
+
+        # "default" config should not be affected by --config
+        devdir = BlockDev.lvm_config_get("devices", "dir", "default")
+        self.assertEqual(devdir, "\"/dev\"")
+
+        # disable global config
+        devdir = BlockDev.lvm_config_get("devices", "dir", "full", global_config=False)
+        self.assertEqual(devdir, "\"/dev\"")
+
+
 class LvmPVonlyTestCase(LVMTestCase):
 
     _sparse_size = 1024**3