1 files changed, 108 insertions, 0 deletions
diff --git a/commands/findmnt.c b/commands/findmnt.c
new file mode 100644
index 0000000000..da8f58835f
--- /dev/null
+++ b/commands/findmnt.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: © 2022 Ahmad Fatoum, Pengutronix
+
+#include <common.h>
+#include <command.h>
+#include <fs.h>
+#include <errno.h>
+#include <getopt.h>
+
+static void print_header(bool *header_printed)
+{
+	if (*header_printed)
+		return;
+	printf("%-20s%-25s%-10s%-20s\n", "TARGET", "SOURCE", "FSTYPE", "OPTIONS");
+	*header_printed = true;
+}
+
+static void report_findmnt(const struct fs_device *fsdev)
+{
+	const char *backingstore;
+
+	backingstore = fsdev->backingstore ?: cdev_name(fsdev->cdev) ?: "none";
+
+	printf("%-20s%-25s%-10s%-20s\n", fsdev->path, backingstore,
+	       fsdev->driver->drv.name, fsdev->options);
+}
+
+static int do_findmnt(int argc, char *argv[])
+{
+	bool header_printed = false;
+	struct fs_device *target = NULL;
+	char *device = NULL;
+	int opt, dirfd = AT_FDCWD;
+
+	while ((opt = getopt(argc, argv, "T:")) > 0) {
+		switch(opt) {
+		case 'T':
+			target = get_fsdevice_by_path(dirfd, optarg);
+			if (!target)
+				return COMMAND_ERROR;
+			break;
+		default:
+			return COMMAND_ERROR_USAGE;
+		}
+	}
+
+	argv += optind;
+	argc -= optind;
+
+	if ((target && argc > 0) || (!target && argc > 1))
+		return COMMAND_ERROR_USAGE;
+
+	if (target) {
+		print_header(&header_printed);
+		report_findmnt(target);
+		return 0;
+	}
+
+	if (argv[0]) {
+		device = canonicalize_path(dirfd, argv[0]);
+		if (!device)
+			return COMMAND_ERROR;
+	}
+
+	for_each_fs_device(target) {
+		if (!device || streq_ptr(target->path, device) ||
+		    streq_ptr(target->backingstore, device)) {
+			print_header(&header_printed);
+			report_findmnt(target);
+		} else {
+			const char *backingstore;
+			struct cdev *cdev;
+
+			cdev = cdev_by_name(devpath_to_name(device));
+			if (!cdev)
+				continue;
+
+			backingstore = target->backingstore;
+			backingstore += str_has_prefix(backingstore, "/dev/");
+
+			if (streq_ptr(backingstore, cdev->name)) {
+				print_header(&header_printed);
+				report_findmnt(target);
+			}
+		}
+	}
+
+	free(device);
+
+	return header_printed ? 0 : COMMAND_ERROR;
+}
+
+BAREBOX_CMD_HELP_START(findmnt)
+BAREBOX_CMD_HELP_TEXT("findmnt will list all mounted filesystems or search")
+BAREBOX_CMD_HELP_TEXT("for a filesystem when given the mountpoint or the")
+BAREBOX_CMD_HELP_TEXT("source device as an argument")
+BAREBOX_CMD_HELP_TEXT("")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT ("-T",  "mount target file path")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(findmnt)
+	.cmd		= do_findmnt,
+	BAREBOX_CMD_DESC("find a file system")
+	BAREBOX_CMD_OPTS("[ DEVICE | -T FILE ]")
+	BAREBOX_CMD_GROUP(CMD_GRP_FILE)
+	BAREBOX_CMD_HELP(cmd_findmnt_help)
+BAREBOX_CMD_END