313 lines
6.8 KiB
C
313 lines
6.8 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2006 NEC Corporation
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*
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* Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/time.h>
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#include <linux/crc32.h>
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#include <linux/jffs2.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/mtd/mtd.h>
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#include "nodelist.h"
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static size_t jffs2_acl_size(int count)
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{
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if (count <= 4) {
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return sizeof(struct jffs2_acl_header)
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+ count * sizeof(struct jffs2_acl_entry_short);
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} else {
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return sizeof(struct jffs2_acl_header)
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+ 4 * sizeof(struct jffs2_acl_entry_short)
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+ (count - 4) * sizeof(struct jffs2_acl_entry);
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}
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}
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static int jffs2_acl_count(size_t size)
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{
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size_t s;
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size -= sizeof(struct jffs2_acl_header);
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if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
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if (size % sizeof(struct jffs2_acl_entry_short))
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return -1;
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return size / sizeof(struct jffs2_acl_entry_short);
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} else {
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s = size - 4 * sizeof(struct jffs2_acl_entry_short);
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if (s % sizeof(struct jffs2_acl_entry))
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return -1;
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return s / sizeof(struct jffs2_acl_entry) + 4;
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}
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}
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static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
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{
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void *end = value + size;
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struct jffs2_acl_header *header = value;
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struct jffs2_acl_entry *entry;
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struct posix_acl *acl;
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uint32_t ver;
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int i, count;
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if (!value)
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return NULL;
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if (size < sizeof(struct jffs2_acl_header))
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return ERR_PTR(-EINVAL);
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ver = je32_to_cpu(header->a_version);
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if (ver != JFFS2_ACL_VERSION) {
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JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
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return ERR_PTR(-EINVAL);
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}
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value += sizeof(struct jffs2_acl_header);
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count = jffs2_acl_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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for (i=0; i < count; i++) {
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entry = value;
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if (value + sizeof(struct jffs2_acl_entry_short) > end)
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goto fail;
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acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
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acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
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switch (acl->a_entries[i].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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value += sizeof(struct jffs2_acl_entry_short);
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break;
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case ACL_USER:
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value += sizeof(struct jffs2_acl_entry);
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if (value > end)
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goto fail;
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acl->a_entries[i].e_uid =
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make_kuid(&init_user_ns,
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je32_to_cpu(entry->e_id));
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break;
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case ACL_GROUP:
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value += sizeof(struct jffs2_acl_entry);
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if (value > end)
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goto fail;
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acl->a_entries[i].e_gid =
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make_kgid(&init_user_ns,
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je32_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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if (value != end)
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goto fail;
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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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static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
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{
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struct jffs2_acl_header *header;
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struct jffs2_acl_entry *entry;
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void *e;
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size_t i;
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*size = jffs2_acl_size(acl->a_count);
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header = kmalloc(struct_size(header, a_entries, acl->a_count),
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GFP_KERNEL);
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if (!header)
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return ERR_PTR(-ENOMEM);
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header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
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e = header + 1;
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for (i=0; i < acl->a_count; i++) {
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const struct posix_acl_entry *acl_e = &acl->a_entries[i];
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entry = e;
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entry->e_tag = cpu_to_je16(acl_e->e_tag);
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entry->e_perm = cpu_to_je16(acl_e->e_perm);
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switch(acl_e->e_tag) {
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case ACL_USER:
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entry->e_id = cpu_to_je32(
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from_kuid(&init_user_ns, acl_e->e_uid));
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e += sizeof(struct jffs2_acl_entry);
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break;
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case ACL_GROUP:
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entry->e_id = cpu_to_je32(
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from_kgid(&init_user_ns, acl_e->e_gid));
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e += sizeof(struct jffs2_acl_entry);
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break;
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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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e += sizeof(struct jffs2_acl_entry_short);
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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 header;
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fail:
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kfree(header);
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return ERR_PTR(-EINVAL);
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}
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struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu)
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{
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struct posix_acl *acl;
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char *value = NULL;
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int rc, xprefix;
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if (rcu)
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return ERR_PTR(-ECHILD);
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switch (type) {
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case ACL_TYPE_ACCESS:
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xprefix = JFFS2_XPREFIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
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break;
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default:
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BUG();
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}
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rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
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if (rc > 0) {
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value = kmalloc(rc, GFP_KERNEL);
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if (!value)
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return ERR_PTR(-ENOMEM);
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rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
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}
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if (rc > 0) {
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acl = jffs2_acl_from_medium(value, rc);
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} else if (rc == -ENODATA || rc == -ENOSYS) {
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acl = NULL;
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} else {
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acl = ERR_PTR(rc);
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}
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kfree(value);
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return acl;
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}
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static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
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{
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char *value = NULL;
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size_t size = 0;
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int rc;
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if (acl) {
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value = jffs2_acl_to_medium(acl, &size);
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if (IS_ERR(value))
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return PTR_ERR(value);
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}
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rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
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if (!value && rc == -ENODATA)
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rc = 0;
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kfree(value);
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return rc;
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}
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int jffs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
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struct posix_acl *acl, int type)
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{
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int rc, xprefix;
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switch (type) {
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case ACL_TYPE_ACCESS:
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xprefix = JFFS2_XPREFIX_ACL_ACCESS;
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if (acl) {
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umode_t mode;
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rc = posix_acl_update_mode(&init_user_ns, inode, &mode,
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&acl);
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if (rc)
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return rc;
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if (inode->i_mode != mode) {
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struct iattr attr;
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attr.ia_valid = ATTR_MODE | ATTR_CTIME;
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attr.ia_mode = mode;
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attr.ia_ctime = current_time(inode);
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rc = jffs2_do_setattr(inode, &attr);
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if (rc < 0)
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return rc;
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}
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}
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break;
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case ACL_TYPE_DEFAULT:
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xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EACCES : 0;
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break;
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default:
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return -EINVAL;
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}
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rc = __jffs2_set_acl(inode, xprefix, acl);
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if (!rc)
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set_cached_acl(inode, type, acl);
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return rc;
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}
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int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
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{
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struct posix_acl *default_acl, *acl;
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int rc;
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cache_no_acl(inode);
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rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
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if (rc)
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return rc;
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if (default_acl) {
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set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
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posix_acl_release(default_acl);
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}
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if (acl) {
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set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
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posix_acl_release(acl);
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}
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return 0;
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}
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int jffs2_init_acl_post(struct inode *inode)
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{
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int rc;
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if (inode->i_default_acl) {
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rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
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if (rc)
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return rc;
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}
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if (inode->i_acl) {
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rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
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if (rc)
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return rc;
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}
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return 0;
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}
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