umount: add -R, --recursive option

This allows unmounting of an entire tree of filesystems, which might be
of particular interest for a shutdown initramfs.

[kzak@redhat.com: - always return MOUNT_EX_* codes
                  - cosmetic changes on coding style]

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 81 insertions, 4 deletions

diff --git a/sys-utils/umount.c b/sys-utils/umount.c
index 38a2fc8f2..196a511ba 100644
--- a/sys-utils/umount.c
+++ b/sys-utils/umount.c
@@ -35,6 +35,7 @@
 #include "optutils.h"
 #include "exitcodes.h"
 #include "closestream.h"
+#include "pathnames.h"
 
 static int table_parser_errcb(struct libmnt_table *tb __attribute__((__unused__)),
 			const char *filename, int line)
@@ -88,6 +89,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 	" -l, --lazy              detach the filesystem now, and cleanup all later\n"));
 	fprintf(out, _(
 	" -O, --test-opts <list>  limit the set of filesystems (use with -a)\n"
+	" -R, --recursive         recursively unmount a target with all its children\n"
 	" -r, --read-only         In case unmounting fails, try to remount read-only\n"
 	" -t, --types <list>      limit the set of filesystem types\n"
 	" -v, --verbose           say what is being done\n"));
@@ -300,9 +302,75 @@ static int umount_one(struct libmnt_context *cxt, const char *spec)
 	return rc;
 }
 
+static int umount_do_recurse(struct libmnt_context *cxt,
+		struct libmnt_table *tb, struct libmnt_fs *parent)
+{
+	int rc;
+	struct libmnt_fs *child;
+	const char *target = mnt_fs_get_target(parent);
+	struct libmnt_iter *itr = mnt_new_iter(MNT_ITER_BACKWARD);
+
+	if (!itr)
+		err(MOUNT_EX_SYSERR, _("libmount iterator allocation failed"));
+	/*
+	 * umount all childern
+	 */
+	for (;;) {
+		rc = mnt_table_next_child_fs(tb, itr, parent, &child);
+		if (rc < 0) {
+			warnx(_("failed to get child fs of %s"), target);
+			rc = MOUNT_EX_SOFTWARE;
+			goto done;
+		} else if (rc == 1)
+			break;		/* no more children */
+
+		rc = umount_do_recurse(cxt, tb, child);
+		if (rc != MOUNT_EX_SUCCESS)
+			goto done;
+	}
+
+	rc = umount_one(cxt, target);
+done:
+	mnt_free_iter(itr);
+	return rc;
+}
+
+static int umount_recursive(struct libmnt_context *cxt, const char *spec)
+{
+	struct libmnt_table *tb;
+	int rc;
+
+	tb = mnt_new_table();
+	if (!tb)
+		err(MOUNT_EX_SYSERR, _("libmount table allocation failed"));
+	/*
+	 * Don't use mtab here. The recursive umount depends on child-parent
+	 * relationship defined by mountinfo file.
+	 */
+	if (mnt_table_parse_file(tb, _PATH_PROC_MOUNTINFO)) {
+		warn(_("failed to parse %s"), _PATH_PROC_MOUNTINFO);
+		rc = MOUNT_EX_SOFTWARE;
+	} else {
+		struct libmnt_fs *fs;
+
+		fs = mnt_table_find_target(tb, spec, MNT_ITER_BACKWARD);
+		if (fs)
+			rc = umount_do_recurse(cxt, tb, fs);
+		else {
+			rc = MOUNT_EX_USAGE;
+			warnx(access(spec, F_OK) == 0 ?
+					_("%s: not mounted") :
+					_("%s: not found"), spec);
+		}
+	}
+
+	mnt_free_table(tb);
+	return rc;
+}
+
 int main(int argc, char **argv)
 {
-	int c, rc = 0, all = 0;
+	int c, rc = 0, all = 0, recursive = 0;
 	struct libmnt_context *cxt;
 	char *types = NULL;
 
@@ -321,6 +389,7 @@ int main(int argc, char **argv)
 		{ "no-canonicalize", 0, 0, 'c' },
 		{ "no-mtab", 0, 0, 'n' },
 		{ "read-only", 0, 0, 'r' },
+		{ "recursive", 0, 0, 'R' },
 		{ "test-opts", 1, 0, 'O' },
 		{ "types", 1, 0, 't' },
 		{ "verbose", 0, 0, 'v' },
@@ -341,7 +410,7 @@ int main(int argc, char **argv)
 
 	mnt_context_set_tables_errcb(cxt, table_parser_errcb);
 
-	while ((c = getopt_long(argc, argv, "acdfhilnrO:t:vV",
+	while ((c = getopt_long(argc, argv, "acdfhilnRrO:t:vV",
 					longopts, NULL)) != -1) {
 
 
@@ -380,6 +449,9 @@ int main(int argc, char **argv)
 		case 'r':
 			mnt_context_enable_rdonly_umount(cxt, TRUE);
 			break;
+		case 'R':
+			recursive = TRUE;
+			break;
 		case 'O':
 			if (mnt_context_set_options_pattern(cxt, optarg))
 				err(MOUNT_EX_SYSERR, _("failed to set options pattern"));
@@ -412,8 +484,13 @@ int main(int argc, char **argv)
 	} else if (argc < 1) {
 		usage(stderr);
 
-	} else while (argc--)
-		rc += umount_one(cxt, *argv++);
+	} else if (recursive) {
+		while (argc--)
+			rc += umount_recursive(cxt, *argv++);
+	} else {
+		while (argc--)
+			rc += umount_one(cxt, *argv++);
+	}
 
 	mnt_free_context(cxt);
 	return rc;