lib/memcat_p.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/slab.h>
   4
   5 /*
   6  * Merge two NULL-terminated pointer arrays into a newly allocated
   7  * array, which is also NULL-terminated. Nomenclature is inspired by
   8  * memset_p() and memcat() found elsewhere in the kernel source tree.
   9  */
  10 void **__memcat_p(void **a, void **b)
  11 {
  12         void **p = a, **new;
  13         int nr;
  14
  15         /* count the elements in both arrays */
  16         for (nr = 0, p = a; *p; nr++, p++)
  17                 ;
  18         for (p = b; *p; nr++, p++)
  19                 ;
  20         /* one for the NULL-terminator */
  21         nr++;
  22
  23         new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL);
  24         if (!new)
  25                 return NULL;
  26
  27         /* nr -> last index; p points to NULL in b[] */
  28         for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1)
  29                 new[nr] = *p;
  30
  31         return new;
  32 }
  33 EXPORT_SYMBOL_GPL(__memcat_p);
  34