[PATCH v3 1/2] xfs_io: add fsuuid command

[Catherine Hoang <catherine.hoang@xxxxxxxxxx>]

Add support for the fsuuid command to retrieve the UUID of a mounted
filesystem.

Signed-off-by: Catherine Hoang <catherine.hoang@xxxxxxxxxx>
Reviewed-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 io/Makefile       |  6 +++---
 io/fsuuid.c       | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 io/init.c         |  1 +
 io/io.h           |  1 +
 man/man8/xfs_io.8 |  3 +++
 5 files changed, 57 insertions(+), 3 deletions(-)
 create mode 100644 io/fsuuid.c

diff --git a/io/Makefile b/io/Makefile
index 498174cf..53fef09e 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -10,12 +10,12 @@ LSRCFILES = xfs_bmap.sh xfs_freeze.sh xfs_mkfile.sh
 HFILES = init.h io.h
 CFILES = init.c \
 	attr.c bmap.c bulkstat.c crc32cselftest.c cowextsize.c encrypt.c \
-	file.c freeze.c fsync.c getrusage.c imap.c inject.c label.c link.c \
-	mmap.c open.c parent.c pread.c prealloc.c pwrite.c reflink.c \
+	file.c freeze.c fsuuid.c fsync.c getrusage.c imap.c inject.c label.c \
+	link.c mmap.c open.c parent.c pread.c prealloc.c pwrite.c reflink.c \
 	resblks.c scrub.c seek.c shutdown.c stat.c swapext.c sync.c \
 	truncate.c utimes.c
 
-LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBFROG) $(LIBPTHREAD)
+LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBFROG) $(LIBPTHREAD) $(LIBUUID)
 LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE) $(LIBFROG)
 LLDFLAGS = -static-libtool-libs
 
diff --git a/io/fsuuid.c b/io/fsuuid.c
new file mode 100644
index 00000000..af2f87a2
--- /dev/null
+++ b/io/fsuuid.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Oracle.
+ * All Rights Reserved.
+ */
+
+#include "libxfs.h"
+#include "command.h"
+#include "init.h"
+#include "io.h"
+#include "libfrog/fsgeom.h"
+#include "libfrog/logging.h"
+
+static cmdinfo_t fsuuid_cmd;
+
+static int
+fsuuid_f(
+	int			argc,
+	char			**argv)
+{
+	struct xfs_fsop_geom	fsgeo;
+	int			ret;
+	char			bp[40];
+
+	ret = -xfrog_geometry(file->fd, &fsgeo);
+
+	if (ret) {
+		xfrog_perror(ret, "XFS_IOC_FSGEOMETRY");
+		exitcode = 1;
+	} else {
+		platform_uuid_unparse((uuid_t *)fsgeo.uuid, bp);
+		printf("UUID = %s\n", bp);
+	}
+
+	return 0;
+}
+
+void
+fsuuid_init(void)
+{
+	fsuuid_cmd.name = "fsuuid";
+	fsuuid_cmd.cfunc = fsuuid_f;
+	fsuuid_cmd.argmin = 0;
+	fsuuid_cmd.argmax = 0;
+	fsuuid_cmd.flags = CMD_FLAG_ONESHOT | CMD_NOMAP_OK;
+	fsuuid_cmd.oneline = _("get mounted filesystem UUID");
+
+	add_command(&fsuuid_cmd);
+}
diff --git a/io/init.c b/io/init.c
index 033ed67d..104cd2c1 100644
--- a/io/init.c
+++ b/io/init.c
@@ -56,6 +56,7 @@ init_commands(void)
 	flink_init();
 	freeze_init();
 	fsmap_init();
+	fsuuid_init();
 	fsync_init();
 	getrusage_init();
 	help_init();
diff --git a/io/io.h b/io/io.h
index 64b7a663..fe474faf 100644
--- a/io/io.h
+++ b/io/io.h
@@ -94,6 +94,7 @@ extern void		encrypt_init(void);
 extern void		file_init(void);
 extern void		flink_init(void);
 extern void		freeze_init(void);
+extern void		fsuuid_init(void);
 extern void		fsync_init(void);
 extern void		getrusage_init(void);
 extern void		help_init(void);
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 223b5152..ef7087b3 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -1455,6 +1455,9 @@ This option is not compatible with the
 flag.
 .RE
 .PD
+.TP
+.B fsuuid
+Print the mounted filesystem UUID.
 
 
 .SH OTHER COMMANDS
-- 
2.25.1