Truct group_info init_groups = {.
Usage = ATOMIC_INIT (2)} ;
struct group_info * groups_alloc (int gidsetsize) { struct group_info * group_info ; int nblocks ; int i ; nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK ; / * Asegúrese de que siempre asignemos al menos un puntero de bloque indirecto * / nblocks = nblocks?
: 1 ; group_info = kmalloc (sizeof ( * group_info) + nblocks * sizeof (gid_t * ), GFP_USER) ; if (!
Group_info) devuelve NULL ; group_info - > ngroups = gidsetsize ; group_info - > nblocks = nblocks ; atomic_set (& group_info - > use, 1) ; if (gidsetsize blocks [0] = group_info - > small_block ; else { for (i = 0 ; i blocks [i] = b ; } } devolver group_info ;
out_undo_partial_alloc : while ( - - i> = 0) { free_page ((sin signo largo) group_info - > blocks [i]) ; } kfree (group_info) ; devuelve NULL ;
}
EXPORT_SYMBOL (groups_alloc) ;
void groups_free (struct group_info * group_info)
{ if (group_info - > blocks [0]!
= group_info - > small_block) { int i ; para (i = 0 ; i nblocks ; i + + ) free_page ((sin signo largo) group_info - > bloques [i]) ; } kfree (group_info) ;
}
EXPORT_SYMBOL (groups_free) ; / * exportar group_info a una matriz de espacio de usuario * /
static int groups_to_user (gid_t __user * grouplist, const struct group_info * group_info)
{ int i ; unsigned int count = group_info - > ngroups ; for (i = 0 ; i nblocks ; i + + ) { unsigned int cp_count = min (NGROUPS_PER_BLOCK, cuenta) ; unsigned int len = cp_count * sizeof ( * grouplist) ; if (copy_to_user (grouplist, group_info - > blocks [i], len)) return - EFAULT ; grouplist + = NGROUPS_PER_BLOCK ; count - = cp_count ; } devuelve 0 ;
} / * rellene un group_info desde una matriz de espacio de usuario : ya debe estar asignado * /
static int groups_from_user (struct group_info * group_info, gid_t __user * grouplist)
{ int i ; unsigned int count = group_info - > ngroups ; for (i = 0 ; i nblocks ; i + + ) { unsigned int cp_count = min (NGROUPS_PER_BLOCK, cuenta) ; unsigned int len = cp_count * sizeof ( * grouplist.