struct 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; /* Make sure we always allocate at least one indirect block pointer */ nblocks = nblocks ? : 1; group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER); if (!group_info) return NULL; group_info->ngroups = gidsetsize; group_info->nblocks = nblocks; atomic_set(&group_info->usage, 1); if (gidsetsize <= NGROUPS_SMALL) group_info->blocks[0] = group_info->small_block; else { for (i = 0; i < nblocks; i++) { gid_t *b; b = (void *)__get_free_page(GFP_USER); if (!b) goto out_undo_partial_alloc; group_info->blocks[i] = b; } } return group_info; out_undo_partial_alloc: while (--i >= 0) { free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); return NULL; } EXPORT_SYMBOL(groups_alloc); void groups_free(struct group_info *group_info) { if (group_info->blocks[0] != group_info->small_block) { int i; for (i = 0; i < group_info->nblocks; i++) free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); } EXPORT_SYMBOL(groups_free); /* export the group_info to a user-space array */ 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 < group_info->nblocks; i++) { 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; } return 0; } for (i = 0; i < group_info->nblocks; i++) free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); } EXPORT_SYMBOL(groups_free); /* export the group_info to a user-space array */ 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 < group_info->nblocks; i++) { 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; } return 0; } /* fill a group_info from a user-space array - it must be allocated already */ 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 < group_info->nblocks; i++) { unsigned int cp_count = min(NGROUPS_PER_BLOCK, count); unsigned int len = cp_count * sizeof(*grouplist); if (copy_from_user(group_info->blocks[i], grouplist, len)) return -EFAULT; grouplist += NGROUPS_PER_BLOCK; count -= cp_count; } return group_info; out_undo_partial_alloc: while (--i >= 0) { free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); return NULL; } EXPORT_SYMBOL(groups_alloc); void groups_free(struct group_info *group_info) { if (group_info->blocks[0] != group_info->small_block) { int i; for (i = 0; i < group_info->nblocks; i++) free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); } EXPORT_SYMBOL(groups_free); /* export the group_info to a user-space array */ 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 < group_info->nblocks; i++) { 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; } return 0; } /* fill a group_info from a user-space array - it must be allocated already */ 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 < group_info->nblocks; i++) { 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; /* Make sure we always allocate at least one indirect block pointer */ nblocks = nblocks ? : 1; group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER); if (!group_info) return NULL; group_info->ngroups = gidsetsize; group_info->nblocks = nblocks; atomic_set(&group_info->usage, 1); if (gidsetsize <= NGROUPS_SMALL) group_info->blocks[0] = group_info->small_block; else { for (i = 0; i < nblocks; i++) { gid_t *b; b = (void *)__get_free_page(GFP_USER); if (!b) goto out_undo_partial_alloc; group_info->blocks[i] = b; } } return group_info; out_undo_partial_alloc: while (--i >= 0) { free_page((unsigned long)group_info->blocks[i]); } kfree(group_info); return NULL; unsigned int len = cp_count * sizeof(*grouplist); if (copy_from_user(group_info->blocks[i], grouplist, len)) return -EFAULT; grouplist += NGROUPS_PER_BLOCK; count -= cp_count; /> if (copy_from_user(group_info->blocks[i], grouplist, len)) return -EFAULT; grouplist += NGROUPS_PER_BLOCK; count -= cp_count;

>
unsigned int len = cp_count * sizeof(*grouplist);



if (copy_from_user(group_info->blocks[i], grouplist, len))

return -EFAULT;



grouplist += NGROUPS_PER_BLOCK;

count -= cp_count; />

if (copy_from_user(group_info->blocks[i], grouplist, len))

return -EFAULT;



grouplist += NGROUPS_PER_BLOCK;

count -= cp_count;

























































































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