-void set_close_on_exec(unsigned int fd, int flag)
-{
- struct files_struct *files = current->files;
- struct fdtable *fdt;
- spin_lock(&files->file_lock);
- fdt = files_fdtable(files);
- if (flag)
- __set_close_on_exec(fd, fdt);
- else
- __clear_close_on_exec(fd, fdt);
- spin_unlock(&files->file_lock);
-}
-
-static bool get_close_on_exec(unsigned int fd)
-{
- struct files_struct *files = current->files;
- struct fdtable *fdt;
- bool res;
- rcu_read_lock();
- fdt = files_fdtable(files);
- res = close_on_exec(fd, fdt);
- rcu_read_unlock();
- return res;
-}
-
-SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
-{
- int err = -EBADF;
- struct file * file, *tofree;
- struct files_struct * files = current->files;
- struct fdtable *fdt;
-
- if ((flags & ~O_CLOEXEC) != 0)
- return -EINVAL;
-
- if (unlikely(oldfd == newfd))
- return -EINVAL;
-
- if (newfd >= rlimit(RLIMIT_NOFILE))
- return -EMFILE;
-
- spin_lock(&files->file_lock);
- err = expand_files(files, newfd);
- file = fcheck(oldfd);
- if (unlikely(!file))
- goto Ebadf;
- if (unlikely(err < 0)) {
- if (err == -EMFILE)
- goto Ebadf;
- goto out_unlock;
- }
- /*
- * We need to detect attempts to do dup2() over allocated but still
- * not finished descriptor. NB: OpenBSD avoids that at the price of
- * extra work in their equivalent of fget() - they insert struct
- * file immediately after grabbing descriptor, mark it larval if
- * more work (e.g. actual opening) is needed and make sure that
- * fget() treats larval files as absent. Potentially interesting,
- * but while extra work in fget() is trivial, locking implications
- * and amount of surgery on open()-related paths in VFS are not.
- * FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
- * deadlocks in rather amusing ways, AFAICS. All of that is out of
- * scope of POSIX or SUS, since neither considers shared descriptor
- * tables and this condition does not arise without those.
- */
- err = -EBUSY;
- fdt = files_fdtable(files);
- tofree = fdt->fd[newfd];
- if (!tofree && fd_is_open(newfd, fdt))
- goto out_unlock;
- get_file(file);
- rcu_assign_pointer(fdt->fd[newfd], file);
- __set_open_fd(newfd, fdt);
- if (flags & O_CLOEXEC)
- __set_close_on_exec(newfd, fdt);
- else
- __clear_close_on_exec(newfd, fdt);
- spin_unlock(&files->file_lock);
-
- if (tofree)
- filp_close(tofree, files);
-
- return newfd;
-
-Ebadf:
- err = -EBADF;
-out_unlock:
- spin_unlock(&files->file_lock);
- return err;
-}
-
-SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
-{
- if (unlikely(newfd == oldfd)) { /* corner case */
- struct files_struct *files = current->files;
- int retval = oldfd;
-
- rcu_read_lock();
- if (!fcheck_files(files, oldfd))
- retval = -EBADF;
- rcu_read_unlock();
- return retval;
- }
- return sys_dup3(oldfd, newfd, 0);
-}
-
-SYSCALL_DEFINE1(dup, unsigned int, fildes)
-{
- int ret = -EBADF;
- struct file *file = fget_raw(fildes);
-
- if (file) {
- ret = get_unused_fd();
- if (ret >= 0)
- fd_install(ret, file);
- else
- fput(file);
- }
- return ret;
-}
-