![Al Viro](/assets/img/avatar_default.png)
New flag for open(2) - O_PATH. Semantics: * pathname is resolved, but the file itself is _NOT_ opened as far as filesystem is concerned. * almost all operations on the resulting descriptors shall fail with -EBADF. Exceptions are: 1) operations on descriptors themselves (i.e. close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD), fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD), fcntl(fd, F_SETFD, ...)) 2) fcntl(fd, F_GETFL), for a common non-destructive way to check if descriptor is open 3) "dfd" arguments of ...at(2) syscalls, i.e. the starting points of pathname resolution * closing such descriptor does *NOT* affect dnotify or posix locks. * permissions are checked as usual along the way to file; no permission checks are applied to the file itself. Of course, giving such thing to syscall will result in permission checks (at the moment it means checking that starting point of ....at() is a directory and caller has exec permissions on it). fget() and fget_light() return NULL on such descriptors; use of fget_raw() and fget_raw_light() is needed to get them. That protects existing code from dealing with those things. There are two things still missing (they come in the next commits): one is handling of symlinks (right now we refuse to open them that way; see the next commit for semantics related to those) and another is descriptor passing via SCM_RIGHTS datagrams. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
854 lines
19 KiB
C
854 lines
19 KiB
C
/*
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* linux/fs/fcntl.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/syscalls.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/capability.h>
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#include <linux/dnotify.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/pipe_fs_i.h>
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#include <linux/security.h>
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#include <linux/ptrace.h>
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#include <linux/signal.h>
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#include <linux/rcupdate.h>
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#include <linux/pid_namespace.h>
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#include <asm/poll.h>
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#include <asm/siginfo.h>
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#include <asm/uaccess.h>
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void set_close_on_exec(unsigned int fd, int flag)
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{
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struct files_struct *files = current->files;
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struct fdtable *fdt;
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spin_lock(&files->file_lock);
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fdt = files_fdtable(files);
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if (flag)
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FD_SET(fd, fdt->close_on_exec);
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else
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FD_CLR(fd, fdt->close_on_exec);
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spin_unlock(&files->file_lock);
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}
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static int get_close_on_exec(unsigned int fd)
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{
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struct files_struct *files = current->files;
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struct fdtable *fdt;
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int res;
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rcu_read_lock();
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fdt = files_fdtable(files);
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res = FD_ISSET(fd, fdt->close_on_exec);
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rcu_read_unlock();
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return res;
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}
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SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
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{
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int err = -EBADF;
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struct file * file, *tofree;
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struct files_struct * files = current->files;
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struct fdtable *fdt;
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if ((flags & ~O_CLOEXEC) != 0)
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return -EINVAL;
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if (unlikely(oldfd == newfd))
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return -EINVAL;
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spin_lock(&files->file_lock);
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err = expand_files(files, newfd);
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file = fcheck(oldfd);
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if (unlikely(!file))
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goto Ebadf;
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if (unlikely(err < 0)) {
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if (err == -EMFILE)
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goto Ebadf;
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goto out_unlock;
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}
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/*
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* We need to detect attempts to do dup2() over allocated but still
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* not finished descriptor. NB: OpenBSD avoids that at the price of
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* extra work in their equivalent of fget() - they insert struct
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* file immediately after grabbing descriptor, mark it larval if
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* more work (e.g. actual opening) is needed and make sure that
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* fget() treats larval files as absent. Potentially interesting,
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* but while extra work in fget() is trivial, locking implications
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* and amount of surgery on open()-related paths in VFS are not.
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* FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
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* deadlocks in rather amusing ways, AFAICS. All of that is out of
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* scope of POSIX or SUS, since neither considers shared descriptor
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* tables and this condition does not arise without those.
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*/
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err = -EBUSY;
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fdt = files_fdtable(files);
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tofree = fdt->fd[newfd];
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if (!tofree && FD_ISSET(newfd, fdt->open_fds))
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goto out_unlock;
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get_file(file);
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rcu_assign_pointer(fdt->fd[newfd], file);
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FD_SET(newfd, fdt->open_fds);
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if (flags & O_CLOEXEC)
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FD_SET(newfd, fdt->close_on_exec);
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else
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FD_CLR(newfd, fdt->close_on_exec);
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spin_unlock(&files->file_lock);
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if (tofree)
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filp_close(tofree, files);
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return newfd;
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Ebadf:
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err = -EBADF;
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out_unlock:
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spin_unlock(&files->file_lock);
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return err;
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}
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SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
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{
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if (unlikely(newfd == oldfd)) { /* corner case */
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struct files_struct *files = current->files;
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int retval = oldfd;
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rcu_read_lock();
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if (!fcheck_files(files, oldfd))
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retval = -EBADF;
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rcu_read_unlock();
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return retval;
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}
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return sys_dup3(oldfd, newfd, 0);
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}
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SYSCALL_DEFINE1(dup, unsigned int, fildes)
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{
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int ret = -EBADF;
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struct file *file = fget_raw(fildes);
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if (file) {
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ret = get_unused_fd();
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if (ret >= 0)
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fd_install(ret, file);
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else
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fput(file);
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}
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return ret;
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}
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#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
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static int setfl(int fd, struct file * filp, unsigned long arg)
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{
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struct inode * inode = filp->f_path.dentry->d_inode;
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int error = 0;
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/*
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* O_APPEND cannot be cleared if the file is marked as append-only
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* and the file is open for write.
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*/
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if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
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return -EPERM;
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/* O_NOATIME can only be set by the owner or superuser */
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if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
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if (!is_owner_or_cap(inode))
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return -EPERM;
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/* required for strict SunOS emulation */
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if (O_NONBLOCK != O_NDELAY)
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if (arg & O_NDELAY)
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arg |= O_NONBLOCK;
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if (arg & O_DIRECT) {
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if (!filp->f_mapping || !filp->f_mapping->a_ops ||
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!filp->f_mapping->a_ops->direct_IO)
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return -EINVAL;
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}
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if (filp->f_op && filp->f_op->check_flags)
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error = filp->f_op->check_flags(arg);
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if (error)
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return error;
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/*
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* ->fasync() is responsible for setting the FASYNC bit.
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*/
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if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op &&
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filp->f_op->fasync) {
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error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
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if (error < 0)
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goto out;
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if (error > 0)
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error = 0;
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}
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spin_lock(&filp->f_lock);
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filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
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spin_unlock(&filp->f_lock);
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out:
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return error;
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}
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static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
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int force)
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{
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write_lock_irq(&filp->f_owner.lock);
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if (force || !filp->f_owner.pid) {
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put_pid(filp->f_owner.pid);
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filp->f_owner.pid = get_pid(pid);
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filp->f_owner.pid_type = type;
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if (pid) {
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const struct cred *cred = current_cred();
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filp->f_owner.uid = cred->uid;
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filp->f_owner.euid = cred->euid;
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}
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}
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write_unlock_irq(&filp->f_owner.lock);
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}
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int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
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int force)
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{
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int err;
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err = security_file_set_fowner(filp);
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if (err)
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return err;
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f_modown(filp, pid, type, force);
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return 0;
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}
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EXPORT_SYMBOL(__f_setown);
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int f_setown(struct file *filp, unsigned long arg, int force)
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{
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enum pid_type type;
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struct pid *pid;
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int who = arg;
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int result;
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type = PIDTYPE_PID;
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if (who < 0) {
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type = PIDTYPE_PGID;
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who = -who;
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}
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rcu_read_lock();
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pid = find_vpid(who);
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result = __f_setown(filp, pid, type, force);
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rcu_read_unlock();
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return result;
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}
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EXPORT_SYMBOL(f_setown);
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void f_delown(struct file *filp)
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{
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f_modown(filp, NULL, PIDTYPE_PID, 1);
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}
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pid_t f_getown(struct file *filp)
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{
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pid_t pid;
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read_lock(&filp->f_owner.lock);
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pid = pid_vnr(filp->f_owner.pid);
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if (filp->f_owner.pid_type == PIDTYPE_PGID)
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pid = -pid;
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read_unlock(&filp->f_owner.lock);
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return pid;
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}
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static int f_setown_ex(struct file *filp, unsigned long arg)
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{
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struct f_owner_ex * __user owner_p = (void * __user)arg;
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struct f_owner_ex owner;
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struct pid *pid;
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int type;
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int ret;
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ret = copy_from_user(&owner, owner_p, sizeof(owner));
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if (ret)
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return -EFAULT;
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switch (owner.type) {
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case F_OWNER_TID:
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type = PIDTYPE_MAX;
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break;
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case F_OWNER_PID:
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type = PIDTYPE_PID;
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break;
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case F_OWNER_PGRP:
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type = PIDTYPE_PGID;
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break;
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default:
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return -EINVAL;
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}
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rcu_read_lock();
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pid = find_vpid(owner.pid);
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if (owner.pid && !pid)
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ret = -ESRCH;
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else
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ret = __f_setown(filp, pid, type, 1);
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rcu_read_unlock();
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return ret;
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}
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static int f_getown_ex(struct file *filp, unsigned long arg)
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{
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struct f_owner_ex * __user owner_p = (void * __user)arg;
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struct f_owner_ex owner;
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int ret = 0;
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read_lock(&filp->f_owner.lock);
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owner.pid = pid_vnr(filp->f_owner.pid);
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switch (filp->f_owner.pid_type) {
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case PIDTYPE_MAX:
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owner.type = F_OWNER_TID;
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break;
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case PIDTYPE_PID:
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owner.type = F_OWNER_PID;
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break;
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case PIDTYPE_PGID:
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owner.type = F_OWNER_PGRP;
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break;
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default:
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WARN_ON(1);
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ret = -EINVAL;
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break;
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}
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read_unlock(&filp->f_owner.lock);
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if (!ret) {
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ret = copy_to_user(owner_p, &owner, sizeof(owner));
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if (ret)
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ret = -EFAULT;
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}
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return ret;
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}
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static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
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struct file *filp)
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{
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long err = -EINVAL;
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switch (cmd) {
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case F_DUPFD:
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case F_DUPFD_CLOEXEC:
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if (arg >= rlimit(RLIMIT_NOFILE))
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break;
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err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
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if (err >= 0) {
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get_file(filp);
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fd_install(err, filp);
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}
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break;
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case F_GETFD:
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err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
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break;
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case F_SETFD:
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err = 0;
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set_close_on_exec(fd, arg & FD_CLOEXEC);
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break;
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case F_GETFL:
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err = filp->f_flags;
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break;
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case F_SETFL:
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err = setfl(fd, filp, arg);
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break;
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case F_GETLK:
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err = fcntl_getlk(filp, (struct flock __user *) arg);
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break;
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case F_SETLK:
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case F_SETLKW:
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err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
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break;
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case F_GETOWN:
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/*
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* XXX If f_owner is a process group, the
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* negative return value will get converted
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* into an error. Oops. If we keep the
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* current syscall conventions, the only way
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* to fix this will be in libc.
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*/
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err = f_getown(filp);
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force_successful_syscall_return();
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break;
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case F_SETOWN:
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err = f_setown(filp, arg, 1);
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break;
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case F_GETOWN_EX:
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err = f_getown_ex(filp, arg);
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break;
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case F_SETOWN_EX:
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err = f_setown_ex(filp, arg);
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break;
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case F_GETSIG:
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err = filp->f_owner.signum;
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break;
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case F_SETSIG:
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/* arg == 0 restores default behaviour. */
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if (!valid_signal(arg)) {
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break;
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}
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err = 0;
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filp->f_owner.signum = arg;
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break;
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case F_GETLEASE:
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err = fcntl_getlease(filp);
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break;
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case F_SETLEASE:
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err = fcntl_setlease(fd, filp, arg);
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break;
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case F_NOTIFY:
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err = fcntl_dirnotify(fd, filp, arg);
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break;
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case F_SETPIPE_SZ:
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case F_GETPIPE_SZ:
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err = pipe_fcntl(filp, cmd, arg);
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break;
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default:
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break;
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}
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return err;
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}
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static int check_fcntl_cmd(unsigned cmd)
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{
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switch (cmd) {
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case F_DUPFD:
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case F_DUPFD_CLOEXEC:
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case F_GETFD:
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case F_SETFD:
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case F_GETFL:
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return 1;
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}
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return 0;
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}
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SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
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{
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struct file *filp;
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long err = -EBADF;
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filp = fget_raw(fd);
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if (!filp)
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goto out;
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if (unlikely(filp->f_mode & FMODE_PATH)) {
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if (!check_fcntl_cmd(cmd)) {
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fput(filp);
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goto out;
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}
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}
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err = security_file_fcntl(filp, cmd, arg);
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if (err) {
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fput(filp);
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return err;
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}
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err = do_fcntl(fd, cmd, arg, filp);
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fput(filp);
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out:
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return err;
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}
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#if BITS_PER_LONG == 32
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SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
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unsigned long, arg)
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{
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struct file * filp;
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long err;
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err = -EBADF;
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filp = fget_raw(fd);
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if (!filp)
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goto out;
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if (unlikely(filp->f_mode & FMODE_PATH)) {
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if (!check_fcntl_cmd(cmd)) {
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fput(filp);
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goto out;
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}
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}
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err = security_file_fcntl(filp, cmd, arg);
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if (err) {
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fput(filp);
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return err;
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}
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err = -EBADF;
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switch (cmd) {
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case F_GETLK64:
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err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
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break;
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case F_SETLK64:
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case F_SETLKW64:
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err = fcntl_setlk64(fd, filp, cmd,
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(struct flock64 __user *) arg);
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break;
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default:
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err = do_fcntl(fd, cmd, arg, filp);
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break;
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}
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fput(filp);
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out:
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return err;
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}
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#endif
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/* Table to convert sigio signal codes into poll band bitmaps */
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static const long band_table[NSIGPOLL] = {
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POLLIN | POLLRDNORM, /* POLL_IN */
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POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
|
|
POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
|
|
POLLERR, /* POLL_ERR */
|
|
POLLPRI | POLLRDBAND, /* POLL_PRI */
|
|
POLLHUP | POLLERR /* POLL_HUP */
|
|
};
|
|
|
|
static inline int sigio_perm(struct task_struct *p,
|
|
struct fown_struct *fown, int sig)
|
|
{
|
|
const struct cred *cred;
|
|
int ret;
|
|
|
|
rcu_read_lock();
|
|
cred = __task_cred(p);
|
|
ret = ((fown->euid == 0 ||
|
|
fown->euid == cred->suid || fown->euid == cred->uid ||
|
|
fown->uid == cred->suid || fown->uid == cred->uid) &&
|
|
!security_file_send_sigiotask(p, fown, sig));
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
static void send_sigio_to_task(struct task_struct *p,
|
|
struct fown_struct *fown,
|
|
int fd, int reason, int group)
|
|
{
|
|
/*
|
|
* F_SETSIG can change ->signum lockless in parallel, make
|
|
* sure we read it once and use the same value throughout.
|
|
*/
|
|
int signum = ACCESS_ONCE(fown->signum);
|
|
|
|
if (!sigio_perm(p, fown, signum))
|
|
return;
|
|
|
|
switch (signum) {
|
|
siginfo_t si;
|
|
default:
|
|
/* Queue a rt signal with the appropriate fd as its
|
|
value. We use SI_SIGIO as the source, not
|
|
SI_KERNEL, since kernel signals always get
|
|
delivered even if we can't queue. Failure to
|
|
queue in this case _should_ be reported; we fall
|
|
back to SIGIO in that case. --sct */
|
|
si.si_signo = signum;
|
|
si.si_errno = 0;
|
|
si.si_code = reason;
|
|
/* Make sure we are called with one of the POLL_*
|
|
reasons, otherwise we could leak kernel stack into
|
|
userspace. */
|
|
BUG_ON((reason & __SI_MASK) != __SI_POLL);
|
|
if (reason - POLL_IN >= NSIGPOLL)
|
|
si.si_band = ~0L;
|
|
else
|
|
si.si_band = band_table[reason - POLL_IN];
|
|
si.si_fd = fd;
|
|
if (!do_send_sig_info(signum, &si, p, group))
|
|
break;
|
|
/* fall-through: fall back on the old plain SIGIO signal */
|
|
case 0:
|
|
do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
|
|
}
|
|
}
|
|
|
|
void send_sigio(struct fown_struct *fown, int fd, int band)
|
|
{
|
|
struct task_struct *p;
|
|
enum pid_type type;
|
|
struct pid *pid;
|
|
int group = 1;
|
|
|
|
read_lock(&fown->lock);
|
|
|
|
type = fown->pid_type;
|
|
if (type == PIDTYPE_MAX) {
|
|
group = 0;
|
|
type = PIDTYPE_PID;
|
|
}
|
|
|
|
pid = fown->pid;
|
|
if (!pid)
|
|
goto out_unlock_fown;
|
|
|
|
read_lock(&tasklist_lock);
|
|
do_each_pid_task(pid, type, p) {
|
|
send_sigio_to_task(p, fown, fd, band, group);
|
|
} while_each_pid_task(pid, type, p);
|
|
read_unlock(&tasklist_lock);
|
|
out_unlock_fown:
|
|
read_unlock(&fown->lock);
|
|
}
|
|
|
|
static void send_sigurg_to_task(struct task_struct *p,
|
|
struct fown_struct *fown, int group)
|
|
{
|
|
if (sigio_perm(p, fown, SIGURG))
|
|
do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
|
|
}
|
|
|
|
int send_sigurg(struct fown_struct *fown)
|
|
{
|
|
struct task_struct *p;
|
|
enum pid_type type;
|
|
struct pid *pid;
|
|
int group = 1;
|
|
int ret = 0;
|
|
|
|
read_lock(&fown->lock);
|
|
|
|
type = fown->pid_type;
|
|
if (type == PIDTYPE_MAX) {
|
|
group = 0;
|
|
type = PIDTYPE_PID;
|
|
}
|
|
|
|
pid = fown->pid;
|
|
if (!pid)
|
|
goto out_unlock_fown;
|
|
|
|
ret = 1;
|
|
|
|
read_lock(&tasklist_lock);
|
|
do_each_pid_task(pid, type, p) {
|
|
send_sigurg_to_task(p, fown, group);
|
|
} while_each_pid_task(pid, type, p);
|
|
read_unlock(&tasklist_lock);
|
|
out_unlock_fown:
|
|
read_unlock(&fown->lock);
|
|
return ret;
|
|
}
|
|
|
|
static DEFINE_SPINLOCK(fasync_lock);
|
|
static struct kmem_cache *fasync_cache __read_mostly;
|
|
|
|
static void fasync_free_rcu(struct rcu_head *head)
|
|
{
|
|
kmem_cache_free(fasync_cache,
|
|
container_of(head, struct fasync_struct, fa_rcu));
|
|
}
|
|
|
|
/*
|
|
* Remove a fasync entry. If successfully removed, return
|
|
* positive and clear the FASYNC flag. If no entry exists,
|
|
* do nothing and return 0.
|
|
*
|
|
* NOTE! It is very important that the FASYNC flag always
|
|
* match the state "is the filp on a fasync list".
|
|
*
|
|
*/
|
|
int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
|
|
{
|
|
struct fasync_struct *fa, **fp;
|
|
int result = 0;
|
|
|
|
spin_lock(&filp->f_lock);
|
|
spin_lock(&fasync_lock);
|
|
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
|
|
if (fa->fa_file != filp)
|
|
continue;
|
|
|
|
spin_lock_irq(&fa->fa_lock);
|
|
fa->fa_file = NULL;
|
|
spin_unlock_irq(&fa->fa_lock);
|
|
|
|
*fp = fa->fa_next;
|
|
call_rcu(&fa->fa_rcu, fasync_free_rcu);
|
|
filp->f_flags &= ~FASYNC;
|
|
result = 1;
|
|
break;
|
|
}
|
|
spin_unlock(&fasync_lock);
|
|
spin_unlock(&filp->f_lock);
|
|
return result;
|
|
}
|
|
|
|
struct fasync_struct *fasync_alloc(void)
|
|
{
|
|
return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
|
|
}
|
|
|
|
/*
|
|
* NOTE! This can be used only for unused fasync entries:
|
|
* entries that actually got inserted on the fasync list
|
|
* need to be released by rcu - see fasync_remove_entry.
|
|
*/
|
|
void fasync_free(struct fasync_struct *new)
|
|
{
|
|
kmem_cache_free(fasync_cache, new);
|
|
}
|
|
|
|
/*
|
|
* Insert a new entry into the fasync list. Return the pointer to the
|
|
* old one if we didn't use the new one.
|
|
*
|
|
* NOTE! It is very important that the FASYNC flag always
|
|
* match the state "is the filp on a fasync list".
|
|
*/
|
|
struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
|
|
{
|
|
struct fasync_struct *fa, **fp;
|
|
|
|
spin_lock(&filp->f_lock);
|
|
spin_lock(&fasync_lock);
|
|
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
|
|
if (fa->fa_file != filp)
|
|
continue;
|
|
|
|
spin_lock_irq(&fa->fa_lock);
|
|
fa->fa_fd = fd;
|
|
spin_unlock_irq(&fa->fa_lock);
|
|
goto out;
|
|
}
|
|
|
|
spin_lock_init(&new->fa_lock);
|
|
new->magic = FASYNC_MAGIC;
|
|
new->fa_file = filp;
|
|
new->fa_fd = fd;
|
|
new->fa_next = *fapp;
|
|
rcu_assign_pointer(*fapp, new);
|
|
filp->f_flags |= FASYNC;
|
|
|
|
out:
|
|
spin_unlock(&fasync_lock);
|
|
spin_unlock(&filp->f_lock);
|
|
return fa;
|
|
}
|
|
|
|
/*
|
|
* Add a fasync entry. Return negative on error, positive if
|
|
* added, and zero if did nothing but change an existing one.
|
|
*/
|
|
static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
|
|
{
|
|
struct fasync_struct *new;
|
|
|
|
new = fasync_alloc();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* fasync_insert_entry() returns the old (update) entry if
|
|
* it existed.
|
|
*
|
|
* So free the (unused) new entry and return 0 to let the
|
|
* caller know that we didn't add any new fasync entries.
|
|
*/
|
|
if (fasync_insert_entry(fd, filp, fapp, new)) {
|
|
fasync_free(new);
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* fasync_helper() is used by almost all character device drivers
|
|
* to set up the fasync queue, and for regular files by the file
|
|
* lease code. It returns negative on error, 0 if it did no changes
|
|
* and positive if it added/deleted the entry.
|
|
*/
|
|
int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
|
|
{
|
|
if (!on)
|
|
return fasync_remove_entry(filp, fapp);
|
|
return fasync_add_entry(fd, filp, fapp);
|
|
}
|
|
|
|
EXPORT_SYMBOL(fasync_helper);
|
|
|
|
/*
|
|
* rcu_read_lock() is held
|
|
*/
|
|
static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
|
|
{
|
|
while (fa) {
|
|
struct fown_struct *fown;
|
|
unsigned long flags;
|
|
|
|
if (fa->magic != FASYNC_MAGIC) {
|
|
printk(KERN_ERR "kill_fasync: bad magic number in "
|
|
"fasync_struct!\n");
|
|
return;
|
|
}
|
|
spin_lock_irqsave(&fa->fa_lock, flags);
|
|
if (fa->fa_file) {
|
|
fown = &fa->fa_file->f_owner;
|
|
/* Don't send SIGURG to processes which have not set a
|
|
queued signum: SIGURG has its own default signalling
|
|
mechanism. */
|
|
if (!(sig == SIGURG && fown->signum == 0))
|
|
send_sigio(fown, fa->fa_fd, band);
|
|
}
|
|
spin_unlock_irqrestore(&fa->fa_lock, flags);
|
|
fa = rcu_dereference(fa->fa_next);
|
|
}
|
|
}
|
|
|
|
void kill_fasync(struct fasync_struct **fp, int sig, int band)
|
|
{
|
|
/* First a quick test without locking: usually
|
|
* the list is empty.
|
|
*/
|
|
if (*fp) {
|
|
rcu_read_lock();
|
|
kill_fasync_rcu(rcu_dereference(*fp), sig, band);
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(kill_fasync);
|
|
|
|
static int __init fcntl_init(void)
|
|
{
|
|
/*
|
|
* Please add new bits here to ensure allocation uniqueness.
|
|
* Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
|
|
* is defined as O_NONBLOCK on some platforms and not on others.
|
|
*/
|
|
BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
|
|
O_RDONLY | O_WRONLY | O_RDWR |
|
|
O_CREAT | O_EXCL | O_NOCTTY |
|
|
O_TRUNC | O_APPEND | /* O_NONBLOCK | */
|
|
__O_SYNC | O_DSYNC | FASYNC |
|
|
O_DIRECT | O_LARGEFILE | O_DIRECTORY |
|
|
O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
|
|
__FMODE_EXEC | O_PATH
|
|
));
|
|
|
|
fasync_cache = kmem_cache_create("fasync_cache",
|
|
sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
|
|
return 0;
|
|
}
|
|
|
|
module_init(fcntl_init)
|