100 строки
2.3 KiB
C
100 строки
2.3 KiB
C
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/*
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* linux/fs/xattr_acl.c
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*
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* Almost all from linux/fs/ext2/acl.c:
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* Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/posix_acl_xattr.h>
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/*
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* Convert from extended attribute to in-memory representation.
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*/
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struct posix_acl *
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posix_acl_from_xattr(const void *value, size_t size)
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{
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posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
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posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
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int count;
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struct posix_acl *acl;
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struct posix_acl_entry *acl_e;
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if (!value)
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return NULL;
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if (size < sizeof(posix_acl_xattr_header))
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return ERR_PTR(-EINVAL);
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if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
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return ERR_PTR(-EOPNOTSUPP);
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count = posix_acl_xattr_count(size);
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if (count < 0)
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return ERR_PTR(-EINVAL);
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if (count == 0)
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return NULL;
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acl = posix_acl_alloc(count, GFP_KERNEL);
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if (!acl)
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return ERR_PTR(-ENOMEM);
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acl_e = acl->a_entries;
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for (end = entry + count; entry != end; acl_e++, entry++) {
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acl_e->e_tag = le16_to_cpu(entry->e_tag);
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acl_e->e_perm = le16_to_cpu(entry->e_perm);
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switch(acl_e->e_tag) {
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case ACL_USER_OBJ:
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case ACL_GROUP_OBJ:
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case ACL_MASK:
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case ACL_OTHER:
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acl_e->e_id = ACL_UNDEFINED_ID;
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break;
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case ACL_USER:
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case ACL_GROUP:
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acl_e->e_id = le32_to_cpu(entry->e_id);
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break;
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default:
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goto fail;
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}
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}
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return acl;
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fail:
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posix_acl_release(acl);
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return ERR_PTR(-EINVAL);
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}
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EXPORT_SYMBOL (posix_acl_from_xattr);
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/*
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* Convert from in-memory to extended attribute representation.
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*/
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int
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posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size)
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{
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posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
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posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
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int real_size, n;
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real_size = posix_acl_xattr_size(acl->a_count);
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if (!buffer)
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return real_size;
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if (real_size > size)
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return -ERANGE;
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ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
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for (n=0; n < acl->a_count; n++, ext_entry++) {
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ext_entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
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ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
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ext_entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
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}
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return real_size;
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}
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EXPORT_SYMBOL (posix_acl_to_xattr);
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