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312 lines
6.8 KiB
312 lines
6.8 KiB
/* |
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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 <[email protected]> |
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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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