readdir: move compat syscalls from compat.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 165 insertions, 0 deletions

diff --git a/fs/readdir.c b/fs/readdir.c
index 0e8a7f355f7a..89659549c09d 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -18,6 +18,7 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/unistd.h>
+#include <linux/compat.h>
 
 #include <linux/uaccess.h>
 
@@ -324,3 +325,167 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
 	fdput_pos(f);
 	return error;
 }
+
+#ifdef CONFIG_COMPAT
+struct compat_old_linux_dirent {
+	compat_ulong_t	d_ino;
+	compat_ulong_t	d_offset;
+	unsigned short	d_namlen;
+	char		d_name[1];
+};
+
+struct compat_readdir_callback {
+	struct dir_context ctx;
+	struct compat_old_linux_dirent __user *dirent;
+	int result;
+};
+
+static int compat_fillonedir(struct dir_context *ctx, const char *name,
+			     int namlen, loff_t offset, u64 ino,
+			     unsigned int d_type)
+{
+	struct compat_readdir_callback *buf =
+		container_of(ctx, struct compat_readdir_callback, ctx);
+	struct compat_old_linux_dirent __user *dirent;
+	compat_ulong_t d_ino;
+
+	if (buf->result)
+		return -EINVAL;
+	d_ino = ino;
+	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+		buf->result = -EOVERFLOW;
+		return -EOVERFLOW;
+	}
+	buf->result++;
+	dirent = buf->dirent;
+	if (!access_ok(VERIFY_WRITE, dirent,
+			(unsigned long)(dirent->d_name + namlen + 1) -
+				(unsigned long)dirent))
+		goto efault;
+	if (	__put_user(d_ino, &dirent->d_ino) ||
+		__put_user(offset, &dirent->d_offset) ||
+		__put_user(namlen, &dirent->d_namlen) ||
+		__copy_to_user(dirent->d_name, name, namlen) ||
+		__put_user(0, dirent->d_name + namlen))
+		goto efault;
+	return 0;
+efault:
+	buf->result = -EFAULT;
+	return -EFAULT;
+}
+
+COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
+		struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
+{
+	int error;
+	struct fd f = fdget_pos(fd);
+	struct compat_readdir_callback buf = {
+		.ctx.actor = compat_fillonedir,
+		.dirent = dirent
+	};
+
+	if (!f.file)
+		return -EBADF;
+
+	error = iterate_dir(f.file, &buf.ctx);
+	if (buf.result)
+		error = buf.result;
+
+	fdput_pos(f);
+	return error;
+}
+
+struct compat_linux_dirent {
+	compat_ulong_t	d_ino;
+	compat_ulong_t	d_off;
+	unsigned short	d_reclen;
+	char		d_name[1];
+};
+
+struct compat_getdents_callback {
+	struct dir_context ctx;
+	struct compat_linux_dirent __user *current_dir;
+	struct compat_linux_dirent __user *previous;
+	int count;
+	int error;
+};
+
+static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
+		loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct compat_linux_dirent __user * dirent;
+	struct compat_getdents_callback *buf =
+		container_of(ctx, struct compat_getdents_callback, ctx);
+	compat_ulong_t d_ino;
+	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
+		namlen + 2, sizeof(compat_long_t));
+
+	buf->error = -EINVAL;	/* only used if we fail.. */
+	if (reclen > buf->count)
+		return -EINVAL;
+	d_ino = ino;
+	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+		buf->error = -EOVERFLOW;
+		return -EOVERFLOW;
+	}
+	dirent = buf->previous;
+	if (dirent) {
+		if (signal_pending(current))
+			return -EINTR;
+		if (__put_user(offset, &dirent->d_off))
+			goto efault;
+	}
+	dirent = buf->current_dir;
+	if (__put_user(d_ino, &dirent->d_ino))
+		goto efault;
+	if (__put_user(reclen, &dirent->d_reclen))
+		goto efault;
+	if (copy_to_user(dirent->d_name, name, namlen))
+		goto efault;
+	if (__put_user(0, dirent->d_name + namlen))
+		goto efault;
+	if (__put_user(d_type, (char  __user *) dirent + reclen - 1))
+		goto efault;
+	buf->previous = dirent;
+	dirent = (void __user *)dirent + reclen;
+	buf->current_dir = dirent;
+	buf->count -= reclen;
+	return 0;
+efault:
+	buf->error = -EFAULT;
+	return -EFAULT;
+}
+
+COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
+		struct compat_linux_dirent __user *, dirent, unsigned int, count)
+{
+	struct fd f;
+	struct compat_linux_dirent __user * lastdirent;
+	struct compat_getdents_callback buf = {
+		.ctx.actor = compat_filldir,
+		.current_dir = dirent,
+		.count = count
+	};
+	int error;
+
+	if (!access_ok(VERIFY_WRITE, dirent, count))
+		return -EFAULT;
+
+	f = fdget_pos(fd);
+	if (!f.file)
+		return -EBADF;
+
+	error = iterate_dir(f.file, &buf.ctx);
+	if (error >= 0)
+		error = buf.error;
+	lastdirent = buf.previous;
+	if (lastdirent) {
+		if (put_user(buf.ctx.pos, &lastdirent->d_off))
+			error = -EFAULT;
+		else
+			error = count - buf.count;
+	}
+	fdput_pos(f);
+	return error;
+}
+#endif