Initial import

1 files changed, 309 insertions, 0 deletions

diff --git a/fs/readdir.c b/fs/readdir.c
new file mode 100644
index 000000000..ced679179
--- /dev/null
+++ b/fs/readdir.c
@@ -0,0 +1,309 @@
+/*
+ *  linux/fs/readdir.c
+ *
+ *  Copyright (C) 1995  Linus Torvalds
+ */
+
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/time.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/dirent.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+
+#include <asm/uaccess.h>
+
+int iterate_dir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	int res = -ENOTDIR;
+	if (!file->f_op->iterate)
+		goto out;
+
+	res = security_file_permission(file, MAY_READ);
+	if (res)
+		goto out;
+
+	res = mutex_lock_killable(&inode->i_mutex);
+	if (res)
+		goto out;
+
+	res = -ENOENT;
+	if (!IS_DEADDIR(inode)) {
+		ctx->pos = file->f_pos;
+		res = file->f_op->iterate(file, ctx);
+		file->f_pos = ctx->pos;
+		fsnotify_access(file);
+		file_accessed(file);
+	}
+	mutex_unlock(&inode->i_mutex);
+out:
+	return res;
+}
+EXPORT_SYMBOL(iterate_dir);
+
+/*
+ * Traditional linux readdir() handling..
+ *
+ * "count=1" is a special case, meaning that the buffer is one
+ * dirent-structure in size and that the code can't handle more
+ * anyway. Thus the special "fillonedir()" function for that
+ * case (the low-level handlers don't need to care about this).
+ */
+
+#ifdef __ARCH_WANT_OLD_READDIR
+
+struct old_linux_dirent {
+	unsigned long	d_ino;
+	unsigned long	d_offset;
+	unsigned short	d_namlen;
+	char		d_name[1];
+};
+
+struct readdir_callback {
+	struct dir_context ctx;
+	struct old_linux_dirent __user * dirent;
+	int result;
+};
+
+static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
+		      loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct readdir_callback *buf =
+		container_of(ctx, struct readdir_callback, ctx);
+	struct old_linux_dirent __user * dirent;
+	unsigned long 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;
+}
+
+SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
+		struct old_linux_dirent __user *, dirent, unsigned int, count)
+{
+	int error;
+	struct fd f = fdget(fd);
+	struct readdir_callback buf = {
+		.ctx.actor = fillonedir,
+		.dirent = dirent
+	};
+
+	if (!f.file)
+		return -EBADF;
+
+	error = iterate_dir(f.file, &buf.ctx);
+	if (buf.result)
+		error = buf.result;
+
+	fdput(f);
+	return error;
+}
+
+#endif /* __ARCH_WANT_OLD_READDIR */
+
+/*
+ * New, all-improved, singing, dancing, iBCS2-compliant getdents()
+ * interface. 
+ */
+struct linux_dirent {
+	unsigned long	d_ino;
+	unsigned long	d_off;
+	unsigned short	d_reclen;
+	char		d_name[1];
+};
+
+struct getdents_callback {
+	struct dir_context ctx;
+	struct linux_dirent __user * current_dir;
+	struct linux_dirent __user * previous;
+	int count;
+	int error;
+};
+
+static int filldir(struct dir_context *ctx, const char *name, int namlen,
+		   loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct linux_dirent __user * dirent;
+	struct getdents_callback *buf =
+		container_of(ctx, struct getdents_callback, ctx);
+	unsigned long d_ino;
+	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
+		sizeof(long));
+
+	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 (__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;
+}
+
+SYSCALL_DEFINE3(getdents, unsigned int, fd,
+		struct linux_dirent __user *, dirent, unsigned int, count)
+{
+	struct fd f;
+	struct linux_dirent __user * lastdirent;
+	struct getdents_callback buf = {
+		.ctx.actor = filldir,
+		.count = count,
+		.current_dir = dirent
+	};
+	int error;
+
+	if (!access_ok(VERIFY_WRITE, dirent, count))
+		return -EFAULT;
+
+	f = fdget(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(f);
+	return error;
+}
+
+struct getdents_callback64 {
+	struct dir_context ctx;
+	struct linux_dirent64 __user * current_dir;
+	struct linux_dirent64 __user * previous;
+	int count;
+	int error;
+};
+
+static int filldir64(struct dir_context *ctx, const char *name, int namlen,
+		     loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct linux_dirent64 __user *dirent;
+	struct getdents_callback64 *buf =
+		container_of(ctx, struct getdents_callback64, ctx);
+	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
+		sizeof(u64));
+
+	buf->error = -EINVAL;	/* only used if we fail.. */
+	if (reclen > buf->count)
+		return -EINVAL;
+	dirent = buf->previous;
+	if (dirent) {
+		if (__put_user(offset, &dirent->d_off))
+			goto efault;
+	}
+	dirent = buf->current_dir;
+	if (__put_user(ino, &dirent->d_ino))
+		goto efault;
+	if (__put_user(0, &dirent->d_off))
+		goto efault;
+	if (__put_user(reclen, &dirent->d_reclen))
+		goto efault;
+	if (__put_user(d_type, &dirent->d_type))
+		goto efault;
+	if (copy_to_user(dirent->d_name, name, namlen))
+		goto efault;
+	if (__put_user(0, dirent->d_name + namlen))
+		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;
+}
+
+SYSCALL_DEFINE3(getdents64, unsigned int, fd,
+		struct linux_dirent64 __user *, dirent, unsigned int, count)
+{
+	struct fd f;
+	struct linux_dirent64 __user * lastdirent;
+	struct getdents_callback64 buf = {
+		.ctx.actor = filldir64,
+		.count = count,
+		.current_dir = dirent
+	};
+	int error;
+
+	if (!access_ok(VERIFY_WRITE, dirent, count))
+		return -EFAULT;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	error = iterate_dir(f.file, &buf.ctx);
+	if (error >= 0)
+		error = buf.error;
+	lastdirent = buf.previous;
+	if (lastdirent) {
+		typeof(lastdirent->d_off) d_off = buf.ctx.pos;
+		if (__put_user(d_off, &lastdirent->d_off))
+			error = -EFAULT;
+		else
+			error = count - buf.count;
+	}
+	fdput(f);
+	return error;
+}