Fix possible NULL dereference in super_by_fd

[thirdparty/mdadm.git] / util.c

diff --git a/util.c b/util.c
index dbe46404c89ae1d00d649b6ecb02292709e5b879..1ad6fd0dc3b5d266b17b0cd92c093a2de17439eb 100644 (file)
--- a/util.c
+++ b/util.c
@@ -757,7 +757,8 @@ struct supertype *super_by_fd(int fd)
 
        if (sra)
                sysfs_free(sra);
-       st->sb = NULL;
+       if (st)
+               st->sb = NULL;
        return st;
 }
 
@@ -862,6 +863,46 @@ void get_one_disk(int mdfd, mdu_array_info_t *ainf, mdu_disk_info_t *disk)
                if (ioctl(mdfd, GET_DISK_INFO, disk) == 0)
                        return;
 }
+
+static int dev2major(int d)
+{
+       if (d >= 0)
+               return MD_MAJOR;
+       else
+               return get_mdp_major();
+}
+
+static int dev2minor(int d)
+{
+       if (d >= 0)
+               return d;
+       return (-1-d) << MdpMinorShift;
+}
+
+int find_free_devnum(int use_partitions)
+{
+       int devnum;
+       for (devnum = 127; devnum != 128;
+            devnum = devnum ? devnum-1 : (1<<22)-1) {
+               char *dn;
+               int _devnum;
+
+               _devnum = use_partitions ? (-1-devnum) : devnum;
+               if (mddev_busy(_devnum))
+                       continue;
+               /* make sure it is new to /dev too, at least as a
+                * non-standard */
+               dn = map_dev(dev2major(_devnum), dev2minor(_devnum), 0);
+               if (dn && ! is_standard(dn, NULL))
+                       continue;
+               break;
+       }
+       if (devnum == 128)
+               return NoMdDev;
+       return use_partitions ? (-1-devnum) : devnum;
+}
+
+
 #ifdef __TINYC__
 /* tinyc doesn't optimize this check in ioctl.h out ... */
 unsigned int __invalid_size_argument_for_IOC = 0;