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Commit fe17f22d authored by Al Viro's avatar Al Viro
Browse files

take purely descriptor-related stuff from fcntl.c to file.c 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6a6d27de

fs/fcntl.c

+3 −128
Original line number Diff line number Diff line
@@ -26,127 +26,6 @@ 
#include <asm/siginfo.h>

#include <asm/uaccess.h>



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;

}



#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)



static int setfl(int fd, struct file * filp, unsigned long arg)
@@ -376,14 +255,10 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, 


	switch (cmd) {

	case F_DUPFD:

	case F_DUPFD_CLOEXEC:

		if (arg >= rlimit(RLIMIT_NOFILE))

		err = f_dupfd(arg, filp, 0);

		break;

		err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);

		if (err >= 0) {

			get_file(filp);

			fd_install(err, filp);

		}

	case F_DUPFD_CLOEXEC:

		err = f_dupfd(arg, filp, FD_CLOEXEC);

		break;

	case F_GETFD:

		err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;

fs/file.c

+132 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 *  Manage the dynamic fd arrays in the process files_struct.

 */



#include <linux/syscalls.h>

#include <linux/export.h>

#include <linux/fs.h>

#include <linux/mm.h>
@@ -794,3 +795,134 @@ struct file *fget_raw_light(unsigned int fd, int *fput_needed) 


	return file;

}



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);

}



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 (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;

}



int f_dupfd(unsigned int from, struct file *file, unsigned flags)

{

	int err;

	if (from >= rlimit(RLIMIT_NOFILE))

		return -EINVAL;

	err = alloc_fd(from, flags);

	if (err >= 0) {

		get_file(file);

		fd_install(err, file);

	}

	return err;

}

include/linux/file.h

+2 −0
Original line number Diff line number Diff line
@@ -30,7 +30,9 @@ extern struct file *fget(unsigned int fd); 
extern struct file *fget_light(unsigned int fd, int *fput_needed);

extern struct file *fget_raw(unsigned int fd);

extern struct file *fget_raw_light(unsigned int fd, int *fput_needed);

extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);

extern void set_close_on_exec(unsigned int fd, int flag);

extern bool get_close_on_exec(unsigned int fd);

extern void put_filp(struct file *);

extern int alloc_fd(unsigned start, unsigned flags);

extern int get_unused_fd_flags(unsigned flags);