[PATCH 0/3] mdadm: Fix some building errors

[Xiao Ni <xni@redhat.com>]

There are some error buildings in Fedora release 26 (Rawhide)
The gcc version is gcc (GCC) 7.0.1 20170211 (Red Hat 7.0.1-0.8)

There are three types of errors:
1. Fall through 
mdadm.c:149:28: error: this statement may fall through [-Werror=implicit-fallthrough=]
    if (mode == ASSEMBLE || mode == BUILD ||
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        mode == CREATE || mode == GROW ||
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        mode == INCREMENTAL || mode == MANAGE)
        ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
mdadm.c:151:3: note: here
   case Brief:
   ^~~~
2. format-overflow
Detail.c: In function ‘Detail’:
Detail.c:584:31: error: ‘%s’ directive writing up to 255 bytes into a region of size 189 [-Werror=format-overflow=]
     sprintf(path, "/sys/block/%s/md/metadata_version",
                               ^~
Detail.c:584:5: note: ‘sprintf’ output between 32 and 287 bytes into a destination of size 200
     sprintf(path, "/sys/block/%s/md/metadata_version",
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      de->d_name);
      ~~~~~~~~~~~
3. format-truncation
super-intel.c: In function ‘examine_super_imsm’:
super-intel.c:1815:30: error: ‘%s’ directive output may be truncated writing up to 31 bytes into a region of size 24 [-Werror=format-truncation=]
  snprintf(str, MPB_SIG_LEN, "%s", mpb->sig);
                              ^~
super-intel.c:1815:2: note: ‘snprintf’ output between 1 and 32 bytes into a destination of size 24
  snprintf(str, MPB_SIG_LEN, "%s", mpb->sig);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Xiao Ni (3):
  Replace snprintf with strncpy at some places to avoid truncation
  Add Wimplicit-fallthrough=0 in Makefile
  Specify enough length when write to buffer

 Detail.c      |  2 +-
 Makefile      |  5 +++++
 super-intel.c | 11 +++++++----
 super0.c      |  2 +-
 util.c        |  2 +-
 5 files changed, 15 insertions(+), 7 deletions(-)

-- 
2.7.4