1 files changed, 45 insertions, 0 deletions
diff --git a/src/shared/dm-util.c b/src/shared/dm-util.c
new file mode 100644
index 0000000..b48b9b5
--- /dev/null
+++ b/src/shared/dm-util.c
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <linux/dm-ioctl.h>
+#include <sys/ioctl.h>
+
+#include "dm-util.h"
+#include "fd-util.h"
+#include "string-util.h"
+
+int dm_deferred_remove_cancel(const char *name) {
+        _cleanup_close_ int fd = -1;
+        struct message {
+                struct dm_ioctl dm_ioctl;
+                struct dm_target_msg dm_target_msg;
+                char msg_text[STRLEN("@cancel_deferred_remove") + 1];
+        } _packed_ message = {
+                .dm_ioctl = {
+                        .version = {
+                                DM_VERSION_MAJOR,
+                                DM_VERSION_MINOR,
+                                DM_VERSION_PATCHLEVEL
+                        },
+                        .data_size = sizeof(struct message),
+                        .data_start = sizeof(struct dm_ioctl),
+                },
+                .msg_text = "@cancel_deferred_remove",
+        };
+
+        assert(name);
+
+        if (strlen(name) >= sizeof(message.dm_ioctl.name))
+                return -ENODEV; /* A device with a name longer than this cannot possibly exist */
+
+        strncpy_exact(message.dm_ioctl.name, name, sizeof(message.dm_ioctl.name));
+
+        fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        if (ioctl(fd, DM_TARGET_MSG, &message))
+                return -errno;
+
+        return 0;
+}