forked from rrcarlosr/Jetpack
327 lines
7.3 KiB
C
327 lines
7.3 KiB
C
/*
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* linux/fs/readdir.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*/
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/time.h>
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#include <linux/mm.h>
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#include <linux/errno.h>
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#include <linux/stat.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/fsnotify.h>
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#include <linux/dirent.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/unistd.h>
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#include <asm/uaccess.h>
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int iterate_dir(struct file *file, struct dir_context *ctx)
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{
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struct inode *inode = file_inode(file);
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bool shared = false;
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int res = -ENOTDIR;
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if (file->f_op->iterate_shared)
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shared = true;
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else if (!file->f_op->iterate)
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goto out;
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res = security_file_permission(file, MAY_READ);
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if (res)
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goto out;
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if (shared) {
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inode_lock_shared(inode);
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} else {
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res = down_write_killable(&inode->i_rwsem);
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if (res)
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goto out;
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}
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res = -ENOENT;
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if (!IS_DEADDIR(inode)) {
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ctx->pos = file->f_pos;
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if (shared)
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res = file->f_op->iterate_shared(file, ctx);
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else
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res = file->f_op->iterate(file, ctx);
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file->f_pos = ctx->pos;
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fsnotify_access(file);
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file_accessed(file);
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}
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if (shared)
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inode_unlock_shared(inode);
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else
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inode_unlock(inode);
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out:
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return res;
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}
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EXPORT_SYMBOL(iterate_dir);
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/*
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* Traditional linux readdir() handling..
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*
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* "count=1" is a special case, meaning that the buffer is one
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* dirent-structure in size and that the code can't handle more
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* anyway. Thus the special "fillonedir()" function for that
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* case (the low-level handlers don't need to care about this).
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*/
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#ifdef __ARCH_WANT_OLD_READDIR
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struct old_linux_dirent {
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unsigned long d_ino;
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unsigned long d_offset;
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unsigned short d_namlen;
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char d_name[1];
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};
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struct readdir_callback {
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struct dir_context ctx;
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struct old_linux_dirent __user * dirent;
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int result;
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};
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static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct readdir_callback *buf =
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container_of(ctx, struct readdir_callback, ctx);
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struct old_linux_dirent __user * dirent;
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unsigned long d_ino;
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if (buf->result)
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return -EINVAL;
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d_ino = ino;
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if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
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buf->result = -EOVERFLOW;
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return -EOVERFLOW;
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}
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buf->result++;
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dirent = buf->dirent;
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if (!access_ok(VERIFY_WRITE, dirent,
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(unsigned long)(dirent->d_name + namlen + 1) -
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(unsigned long)dirent))
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goto efault;
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if ( __put_user(d_ino, &dirent->d_ino) ||
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__put_user(offset, &dirent->d_offset) ||
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__put_user(namlen, &dirent->d_namlen) ||
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__copy_to_user(dirent->d_name, name, namlen) ||
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__put_user(0, dirent->d_name + namlen))
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goto efault;
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return 0;
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efault:
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buf->result = -EFAULT;
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return -EFAULT;
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}
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SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
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struct old_linux_dirent __user *, dirent, unsigned int, count)
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{
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int error;
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struct fd f = fdget_pos(fd);
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struct readdir_callback buf = {
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.ctx.actor = fillonedir,
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.dirent = dirent
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};
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if (!f.file)
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return -EBADF;
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error = iterate_dir(f.file, &buf.ctx);
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if (buf.result)
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error = buf.result;
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fdput_pos(f);
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return error;
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}
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#endif /* __ARCH_WANT_OLD_READDIR */
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/*
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* New, all-improved, singing, dancing, iBCS2-compliant getdents()
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* interface.
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*/
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struct linux_dirent {
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unsigned long d_ino;
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unsigned long d_off;
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unsigned short d_reclen;
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char d_name[1];
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};
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struct getdents_callback {
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struct dir_context ctx;
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struct linux_dirent __user * current_dir;
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struct linux_dirent __user * previous;
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int count;
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int error;
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};
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static int filldir(struct dir_context *ctx, const char *name, int namlen,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct linux_dirent __user * dirent;
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struct getdents_callback *buf =
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container_of(ctx, struct getdents_callback, ctx);
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unsigned long d_ino;
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int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
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sizeof(long));
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buf->error = -EINVAL; /* only used if we fail.. */
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if (reclen > buf->count)
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return -EINVAL;
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d_ino = ino;
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if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
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buf->error = -EOVERFLOW;
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return -EOVERFLOW;
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}
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dirent = buf->previous;
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if (dirent) {
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if (signal_pending(current))
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return -EINTR;
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if (__put_user(offset, &dirent->d_off))
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goto efault;
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}
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dirent = buf->current_dir;
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if (__put_user(d_ino, &dirent->d_ino))
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goto efault;
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if (__put_user(reclen, &dirent->d_reclen))
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goto efault;
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if (copy_to_user(dirent->d_name, name, namlen))
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goto efault;
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if (__put_user(0, dirent->d_name + namlen))
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goto efault;
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if (__put_user(d_type, (char __user *) dirent + reclen - 1))
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goto efault;
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buf->previous = dirent;
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dirent = (void __user *)dirent + reclen;
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buf->current_dir = dirent;
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buf->count -= reclen;
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return 0;
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efault:
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buf->error = -EFAULT;
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return -EFAULT;
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}
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SYSCALL_DEFINE3(getdents, unsigned int, fd,
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struct linux_dirent __user *, dirent, unsigned int, count)
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{
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struct fd f;
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struct linux_dirent __user * lastdirent;
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struct getdents_callback buf = {
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.ctx.actor = filldir,
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.count = count,
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.current_dir = dirent
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};
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int error;
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if (!access_ok(VERIFY_WRITE, dirent, count))
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return -EFAULT;
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f = fdget_pos(fd);
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if (!f.file)
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return -EBADF;
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error = iterate_dir(f.file, &buf.ctx);
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if (error >= 0)
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error = buf.error;
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lastdirent = buf.previous;
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if (lastdirent) {
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if (put_user(buf.ctx.pos, &lastdirent->d_off))
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error = -EFAULT;
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else
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error = count - buf.count;
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}
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fdput_pos(f);
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return error;
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}
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struct getdents_callback64 {
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struct dir_context ctx;
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struct linux_dirent64 __user * current_dir;
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struct linux_dirent64 __user * previous;
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int count;
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int error;
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};
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static int filldir64(struct dir_context *ctx, const char *name, int namlen,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct linux_dirent64 __user *dirent;
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struct getdents_callback64 *buf =
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container_of(ctx, struct getdents_callback64, ctx);
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int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
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sizeof(u64));
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buf->error = -EINVAL; /* only used if we fail.. */
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if (reclen > buf->count)
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return -EINVAL;
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dirent = buf->previous;
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if (dirent) {
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if (signal_pending(current))
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return -EINTR;
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if (__put_user(offset, &dirent->d_off))
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goto efault;
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}
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dirent = buf->current_dir;
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if (__put_user(ino, &dirent->d_ino))
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goto efault;
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if (__put_user(0, &dirent->d_off))
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goto efault;
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if (__put_user(reclen, &dirent->d_reclen))
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goto efault;
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if (__put_user(d_type, &dirent->d_type))
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goto efault;
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if (copy_to_user(dirent->d_name, name, namlen))
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goto efault;
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if (__put_user(0, dirent->d_name + namlen))
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goto efault;
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buf->previous = dirent;
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dirent = (void __user *)dirent + reclen;
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buf->current_dir = dirent;
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buf->count -= reclen;
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return 0;
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efault:
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buf->error = -EFAULT;
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return -EFAULT;
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}
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SYSCALL_DEFINE3(getdents64, unsigned int, fd,
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struct linux_dirent64 __user *, dirent, unsigned int, count)
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{
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struct fd f;
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struct linux_dirent64 __user * lastdirent;
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struct getdents_callback64 buf = {
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.ctx.actor = filldir64,
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.count = count,
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.current_dir = dirent
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};
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int error;
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if (!access_ok(VERIFY_WRITE, dirent, count))
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return -EFAULT;
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f = fdget_pos(fd);
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if (!f.file)
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return -EBADF;
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error = iterate_dir(f.file, &buf.ctx);
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if (error >= 0)
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error = buf.error;
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lastdirent = buf.previous;
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if (lastdirent) {
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typeof(lastdirent->d_off) d_off = buf.ctx.pos;
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if (__put_user(d_off, &lastdirent->d_off))
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error = -EFAULT;
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else
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error = count - buf.count;
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}
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fdput_pos(f);
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return error;
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}
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