findmnt: make xalloc use mroe robust

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1807003
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index a4b7a1b3a9cf10c854de304699fb6a6f19159e45..53f647fc1a8bb672e2f1093f79815f38092ca2ba 100644 (file)
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -533,22 +533,28 @@ static char *get_data(struct libmnt_fs *fs, int num)
                break;
        }
        case COL_TARGET:
-               str = xstrdup(mnt_fs_get_target(fs));
+               if (mnt_fs_get_target(fs))
+                       str = xstrdup(mnt_fs_get_target(fs));
                break;
        case COL_FSTYPE:
-               str = xstrdup(mnt_fs_get_fstype(fs));
+               if (mnt_fs_get_fstype(fs))
+                       str = xstrdup(mnt_fs_get_fstype(fs));
                break;
        case COL_OPTIONS:
-               str = xstrdup(mnt_fs_get_options(fs));
+               if (mnt_fs_get_options(fs))
+                       str = xstrdup(mnt_fs_get_options(fs));
                break;
        case COL_VFS_OPTIONS:
-               str = xstrdup(mnt_fs_get_vfs_options(fs));
+               if (mnt_fs_get_vfs_options(fs))
+                       str = xstrdup(mnt_fs_get_vfs_options(fs));
                break;
        case COL_FS_OPTIONS:
-               str = xstrdup(mnt_fs_get_fs_options(fs));
+               if (mnt_fs_get_fs_options(fs))
+                       str = xstrdup(mnt_fs_get_fs_options(fs));
                break;
        case COL_OPT_FIELDS:
-               str = xstrdup(mnt_fs_get_optional_fields(fs));
+               if (mnt_fs_get_optional_fields(fs))
+                       str = xstrdup(mnt_fs_get_optional_fields(fs));
                break;
        case COL_UUID:
                str = get_tag(fs, "UUID", col_id);
@@ -582,7 +588,8 @@ static char *get_data(struct libmnt_fs *fs, int num)
                str = get_vfs_attr(fs, col_id);
                break;
        case COL_FSROOT:
-               str = xstrdup(mnt_fs_get_root(fs));
+               if (mnt_fs_get_root(fs))
+                       str = xstrdup(mnt_fs_get_root(fs));
                break;
        case COL_TID:
                if (mnt_fs_get_tid(fs))
@@ -659,12 +666,14 @@ static char *get_tabdiff_data(struct libmnt_fs *old_fs,
                break;
        case COL_OLD_OPTIONS:
                if (old_fs && (change == MNT_TABDIFF_REMOUNT ||
-                              change == MNT_TABDIFF_UMOUNT))
+                              change == MNT_TABDIFF_UMOUNT)
+                          && mnt_fs_get_options(old_fs))
                        str = xstrdup(mnt_fs_get_options(old_fs));
                break;
        case COL_OLD_TARGET:
                if (old_fs && (change == MNT_TABDIFF_MOVE ||
-                              change == MNT_TABDIFF_UMOUNT))
+                              change == MNT_TABDIFF_UMOUNT)
+                          && mnt_fs_get_target(old_fs))
                        str = xstrdup(mnt_fs_get_target(old_fs));
                break;
        default: