/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2018 Nexenta Systems, Inc.  All rights reserved.
 */

/*
 * Support functions for smb2_ioctl/fsctl codes:
 * FSCTL_SET_SPARSE
 * FSCTL_SET_ZERO_DATA
 * FSCTL_QUERY_ALLOCATED_RANGES
 */

#include <smbsrv/smb2_kproto.h>
#include <smbsrv/smb_fsops.h>
#include <smb/winioctl.h>

/*
 * FSCTL_SET_SPARSE
 *
 * In args: one byte flag (optional: default TRUE)
 */
uint32_t
smb2_fsctl_set_sparse(smb_request_t *sr, smb_fsctl_t *fsctl)
{
	smb_attr_t attr;
	smb_ofile_t *ofile = sr->fid_ofile;
	cred_t *kcr;
	uint32_t amask;
	uint32_t status;
	uint8_t flag;
	int rc;

	rc = smb_mbc_decodef(fsctl->in_mbc, "b", &flag);
	if (rc != 0)
		flag = 0xff;

	if (!smb_node_is_file(ofile->f_node))
		return (NT_STATUS_INVALID_PARAMETER);

	/*
	 * Allow if we have any of FILE_WRITE_ATTRIBUTES,
	 * FILE_WRITE_DATA, FILE_APPEND_DATA
	 */
	amask = FILE_WRITE_ATTRIBUTES | FILE_WRITE_DATA | FILE_APPEND_DATA;
	if ((ofile->f_granted_access & amask) == 0)
		return (NT_STATUS_ACCESS_DENIED);

	/*
	 * Need the current DOS attributes
	 */
	bzero(&attr, sizeof (attr));
	attr.sa_mask = SMB_AT_DOSATTR;
	kcr = zone_kcred();
	status = smb_node_getattr(sr, ofile->f_node, kcr, ofile, &attr);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	if (flag != 0) {
		/* Set "sparse" */
		if (attr.sa_dosattr & FILE_ATTRIBUTE_SPARSE_FILE)
			return (0);
		attr.sa_dosattr |= FILE_ATTRIBUTE_SPARSE_FILE;
	} else {
		/* Clear "sparse" */
		if ((attr.sa_dosattr & FILE_ATTRIBUTE_SPARSE_FILE) == 0)
			return (0);
		attr.sa_dosattr &= ~FILE_ATTRIBUTE_SPARSE_FILE;
	}

	attr.sa_mask = SMB_AT_DOSATTR;
	status = smb_node_setattr(sr, ofile->f_node, kcr, ofile, &attr);
	return (status);
}

/*
 * FSCTL_SET_ZERO_DATA
 *
 * In args: uint64_t start_off, end_off
 */
uint32_t
smb2_fsctl_set_zero_data(smb_request_t *sr, smb_fsctl_t *fsctl)
{
	smb_attr_t attr;
	smb_ofile_t *ofile = sr->fid_ofile;
	uint64_t start_off, end_off, zero_len;
	uint32_t status;
	int rc;

	rc = smb_mbc_decodef(fsctl->in_mbc, "qq",
	    &start_off, &end_off);
	if (rc != 0)
		return (NT_STATUS_BUFFER_TOO_SMALL);

	/*
	 * The given offsets are actually int64_t (signed).
	 */
	if (start_off > INT64_MAX ||
	    end_off > INT64_MAX ||
	    start_off > end_off)
		return (NT_STATUS_INVALID_PARAMETER);

	if (!smb_node_is_file(ofile->f_node))
		return (NT_STATUS_INVALID_PARAMETER);

	/*
	 * This operation is effectively a write (of zeros)
	 */
	status = smb_ofile_access(ofile, ofile->f_cr, FILE_WRITE_DATA);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	/*
	 * Need the file size
	 */
	bzero(&attr, sizeof (attr));
	attr.sa_mask = SMB_AT_SIZE;
	status = smb_node_getattr(sr, ofile->f_node, ofile->f_cr,
	    ofile, &attr);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	/*
	 * Ignore any zero-ing beyond EOF
	 */
	if (end_off > attr.sa_vattr.va_size)
		end_off = attr.sa_vattr.va_size;
	if (start_off >= end_off)
		return (0);
	zero_len = end_off - start_off;

	/*
	 * Check for lock conflicting with the write.
	 */
	status = smb_lock_range_access(sr, ofile->f_node,
	    start_off, zero_len, B_TRUE);
	if (status != 0)
		return (status); /* == FILE_LOCK_CONFLICT */

	rc = smb_fsop_freesp(sr, ofile->f_cr, ofile,
	    start_off, zero_len);
	if (rc != 0)
		status = smb_errno2status(rc);

	return (status);
}

/*
 * FSCTL_QUERY_ALLOCATED_RANGES
 *
 * Incoming args: uint64_t start_off, end_off
 */
struct alloc_range {
	off64_t off;
	off64_t len;
};
uint32_t
smb2_fsctl_query_alloc_ranges(smb_request_t *sr, smb_fsctl_t *fsctl)
{
	smb_attr_t attr;
	cred_t *kcr;
	smb_ofile_t *ofile = sr->fid_ofile;
	struct alloc_range arg, res;
	off64_t cur_off, end_off;
	uint32_t status;
	int err, rc;

	/*
	 * Most ioctls return NT_STATUS_BUFFER_TOO_SMALL for
	 * short in/out buffers, but for this one, MS-FSA
	 * says short input returns invalid parameter.
	 */
	rc = smb_mbc_decodef(fsctl->in_mbc, "qq", &arg.off, &arg.len);
	if (rc != 0)
		return (NT_STATUS_INVALID_PARAMETER);

	/*
	 * The given offsets are actually int64_t (signed).
	 */
	end_off = arg.off + arg.len;
	if (arg.off > INT64_MAX || arg.len < 0 ||
	    end_off > INT64_MAX || end_off < arg.off)
		return (NT_STATUS_INVALID_PARAMETER);

	if (!smb_node_is_file(ofile->f_node))
		return (NT_STATUS_INVALID_PARAMETER);

	/*
	 * This operation is effectively a read
	 */
	status = smb_ofile_access(ofile, ofile->f_cr, FILE_READ_DATA);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	if (arg.len == 0) {
		/* MS-FSA says empty result for this. */
		return (0);
	}

	/*
	 * Need the file size and dosattr
	 */
	bzero(&attr, sizeof (attr));
	attr.sa_mask = SMB_AT_SIZE | SMB_AT_DOSATTR;
	kcr = zone_kcred();
	status = smb_node_getattr(sr, ofile->f_node, kcr, ofile, &attr);
	if (status != NT_STATUS_SUCCESS)
		return (status);
	if (end_off > attr.sa_vattr.va_size)
		end_off = attr.sa_vattr.va_size;

	/*
	 * Only sparse files should present un-allocated ranges.
	 * If non-sparse, MS-FSA says (just return one range).
	 */
	if ((attr.sa_dosattr & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {
		if (arg.off < end_off) {
			res.off = arg.off;
			res.len = end_off - arg.off;
			rc = smb_mbc_encodef(fsctl->out_mbc, "qq",
			    res.off, res.len);
			if (rc != 0)
				return (NT_STATUS_BUFFER_TOO_SMALL);
		}
		return (0);
	}

	cur_off = arg.off;
	while (cur_off < end_off) {
		off64_t data, hole;

		data = cur_off;
		err = smb_fsop_next_alloc_range(kcr, ofile->f_node,
		    &data, &hole);
		if (err != 0)
			break;

		/* sanity check data (ensure progress) */
		if (data < cur_off) {
			ASSERT(0);
			data = cur_off;
		}

		/* Normal termination */
		if (data >= end_off)
			break;

		/* sanity check hole (ensure progress) */
		if (hole <= data)
			hole = end_off;

		/* Trim this range as needed. */
		if (hole > end_off)
			hole = end_off;

		res.off = data;
		res.len = hole - data;

		if (res.len > 0) {
			rc = smb_mbc_encodef(fsctl->out_mbc, "qq",
			    res.off, res.len);
			if (rc != 0)
				return (NT_STATUS_BUFFER_TOO_SMALL);
		}

		cur_off = hole;
	}

	return (0);
}

/*
 * Copy a segment of a file, preserving sparseness.
 * Uses a caller-provided buffer for read/write.
 * Caller should already have checked for locks.
 *
 * On entry, *residp is the length to copy.
 * On return, it's the "resid" (amount not copied)
 *
 * If this gets an error from any I/O, return it, even if some data
 * have already been copied.  The caller should normally ignore an
 * error when some data have been copied.
 */
uint32_t
smb2_sparse_copy(
	smb_request_t *sr,
	smb_ofile_t *src_ofile, smb_ofile_t *dst_ofile,
	off64_t src_off, off64_t dst_off, uint32_t *residp,
	void *buffer, size_t bufsize)
{
	iovec_t iov;
	uio_t uio;
	off64_t data, hole;
	uint32_t xfer;
	uint32_t status = 0;
	int rc;

	while (*residp > 0) {

		data = src_off;
		rc = smb_fsop_next_alloc_range(src_ofile->f_cr,
		    src_ofile->f_node, &data, &hole);
		switch (rc) {
		case 0:
			/* Found data, hole */
			break;
		case ENXIO:
			/* No data after here (will skip below). */
			data = hole = (src_off + *residp);
			break;
		default:
			cmn_err(CE_NOTE,
			    "smb_fsop_next_alloc_range: rc=%d", rc);
			/* FALLTHROUGH */
		case ENOSYS:	/* FS does not support VOP_IOCTL... */
		case ENOTTY:	/* ... or _FIO_SEEK_DATA, _HOLE */
			data = src_off;
			hole = src_off + *residp;
			break;
		}

		/*
		 * Don't try to go past (src_off + *residp)
		 */
		if (hole > (src_off + *residp))
			hole = src_off + *residp;
		if (data > hole)
			data = hole;

		/*
		 * If there's a gap (src_off .. data)
		 * skip in src_ofile, zero in dst_ofile
		 */
		if (src_off < data) {
			off64_t skip = data - src_off;
			rc = smb_fsop_freesp(sr, dst_ofile->f_cr,
			    dst_ofile, dst_off, skip);
			if (rc == 0) {
				src_off += skip;
				dst_off += skip;
				*residp -= (uint32_t)skip;
			} else {
				/* Fall back to regular copy */
				data = src_off;
			}
		}
		ASSERT(src_off == data);

		/*
		 * Copy this segment: src_off .. hole
		 */
		while (src_off < hole) {
			ssize_t tsize = hole - src_off;
			if (tsize > bufsize)
				tsize = bufsize;

			/*
			 * Read src_ofile into buffer
			 */
			iov.iov_base = buffer;
			iov.iov_len  = tsize;
			bzero(&uio, sizeof (uio));
			uio.uio_iov = &iov;
			uio.uio_iovcnt = 1;
			uio.uio_resid = tsize;
			uio.uio_loffset = src_off;
			uio.uio_segflg = UIO_SYSSPACE;
			uio.uio_extflg = UIO_COPY_DEFAULT;

			rc = smb_fsop_read(sr, src_ofile->f_cr,
			    src_ofile->f_node, src_ofile, &uio, 0);
			if (rc != 0) {
				status = smb_errno2status(rc);
				return (status);
			}
			/* Note: Could be partial read. */
			tsize -= uio.uio_resid;
			ASSERT(tsize > 0);

			/*
			 * Write buffer to dst_ofile
			 */
			iov.iov_base = buffer;
			iov.iov_len  = tsize;
			bzero(&uio, sizeof (uio));
			uio.uio_iov = &iov;
			uio.uio_iovcnt = 1;
			uio.uio_resid = tsize;
			uio.uio_loffset = dst_off;
			uio.uio_segflg = UIO_SYSSPACE;
			uio.uio_extflg = UIO_COPY_DEFAULT;

			rc = smb_fsop_write(sr, dst_ofile->f_cr,
			    dst_ofile->f_node, dst_ofile, &uio, &xfer, 0);
			if (rc != 0) {
				status = smb_errno2status(rc);
				return (status);
			}
			ASSERT(xfer <= tsize);

			src_off += xfer;
			dst_off += xfer;
			*residp -= xfer;
		}
		ASSERT(src_off == hole);
	}

	return (status);
}

/*
 * Not sure what header this might go in.
 */
#define	FILE_REGION_USAGE_VALID_CACHED_DATA	1
#define	FILE_REGION_USAGE_VALID_NONCACHED_DATA	2
#define	FILE_REGION_USAGE_VALID__MASK		3

typedef struct _FILE_REGION_INFO {
	uint64_t off;
	uint64_t len;
	uint32_t usage;
	uint32_t reserved;
} FILE_REGION_INFO;


/*
 * FSCTL_QUERY_FILE_REGIONS
 *
 * [MS-FSCC] 2.3.39 FSCTL_QUERY_FILE_REGIONS Request
 * [MS-FSCC] 2.3.40.1 FILE_REGION_INFO
 *
 * Looks like Hyper-V uses this to query the "valid data length",
 * which to us is the beginning offset of the last "hole".
 * Similar logic as smb2_sparse_copy()
 */
uint32_t
smb2_fsctl_query_file_regions(smb_request_t *sr, smb_fsctl_t *fsctl)
{
	smb_attr_t attr;
	cred_t *kcr;
	smb_ofile_t *ofile = sr->fid_ofile;
	FILE_REGION_INFO arg;
	off64_t cur_off, end_off, eof;
	off64_t data, hole;
	uint32_t tot_regions, put_regions;
	uint32_t status;
	int rc;

	if (fsctl->InputCount == 0) {
		arg.off = 0;
		arg.len = INT64_MAX;
		arg.usage = FILE_REGION_USAGE_VALID_CACHED_DATA;
		arg.reserved = 0;
	} else {
		/* min size check: reserved is optional */
		rc = smb_mbc_decodef(fsctl->in_mbc, "qql",
		    &arg.off, &arg.len, &arg.usage);
		if (rc != 0)
			return (NT_STATUS_BUFFER_TOO_SMALL);

		/*
		 * The given offset and length are int64_t (signed).
		 */
		if (arg.off > INT64_MAX || arg.len > INT64_MAX)
			return (NT_STATUS_INVALID_PARAMETER);
		if ((arg.off + arg.len) > INT64_MAX)
			return (NT_STATUS_INVALID_PARAMETER);
		if ((arg.usage & FILE_REGION_USAGE_VALID__MASK) == 0)
			return (NT_STATUS_INVALID_PARAMETER);
		arg.reserved = 0;
	}

	if (fsctl->MaxOutputResp < (16 + sizeof (FILE_REGION_INFO)))
		return (NT_STATUS_BUFFER_TOO_SMALL);

	if (!smb_node_is_file(ofile->f_node))
		return (NT_STATUS_INVALID_PARAMETER);

	/*
	 * This operation is effectively a read
	 */
	status = smb_ofile_access(ofile, ofile->f_cr, FILE_READ_DATA);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	/*
	 * Need the file size and dosattr
	 */
	bzero(&attr, sizeof (attr));
	attr.sa_mask = SMB_AT_SIZE | SMB_AT_DOSATTR;
	kcr = zone_kcred();
	status = smb_node_getattr(sr, ofile->f_node, kcr, ofile, &attr);
	if (status != NT_STATUS_SUCCESS)
		return (status);

	cur_off = arg.off;
	end_off = arg.off + arg.len;
	eof = attr.sa_vattr.va_size;

	/*
	 * If (InputRegion.FileOffset > Eof) OR
	 * ((InputRegion.FileOffset == Eof) AND (Eof > 0)),
	 * the operation MUST return STATUS_SUCCESS, with
	 * BytesReturned set to 0 (empty data response)
	 */
	if ((arg.off > eof) || (arg.off == eof && eof > 0))
		return (NT_STATUS_SUCCESS);
	if (end_off > eof)
		end_off = eof;

	/*
	 * We're going to return at least one region.  Put place-holder
	 * data for the fixed part of the response.  Will overwrite this
	 * later, when we know how many regions there are and how many
	 * of those fit in the allowed response buffer space.  These are:
	 * Flags, TotalRegionEntryCount, RegionEntryCount, Reserved
	 */
	rc = smb_mbc_encodef(fsctl->out_mbc, "llll", 0, 0, 0, 0);
	if (rc != 0)
		return (NT_STATUS_BUFFER_TOO_SMALL);
	tot_regions = put_regions = 0;

	/*
	 * Get the first pair of (data, hole) offsets at or after
	 * the current offset (cur_off).
	 */
	data = hole = cur_off;
	rc = smb_fsop_next_alloc_range(ofile->f_cr,
	    ofile->f_node, &data, &hole);
	switch (rc) {
	case 0:
		/* Found (data, hole) */
		break;
	case ENXIO:
		/* No more data after cur_off. */
		break;
	default:
		cmn_err(CE_NOTE, "smb_fsop_next_alloc_range: rc=%d", rc);
		/* FALLTHROUGH */
	case ENOSYS:	/* FS does not support VOP_IOCTL... */
	case ENOTTY:	/* ... or _FIO_SEEK_DATA, _HOLE */
		data = cur_off;
		hole = eof;
		break;
	}
	DTRACE_PROBE2(range0, uint64_t, data, uint64_t, hole);

	/*
	 * Only sparse files should present un-allocated regions.
	 * If non-sparse, MS-FSA says to just return one region.
	 * There still can be a "hole" but only one, starting at
	 * "valid data length" (VDL) and ending at end of file.
	 * To determine VDL, find the last (data,hole) pair, then
	 * VDL is the last "hole" offset.  Note that the above
	 * smb_fsop_next_alloc_range may have set data somewhere
	 * above cur_off, so we we have to reset that here.
	 */
	if ((attr.sa_dosattr & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {
		/*
		 * This works, but it's rather inefficient, and
		 * usually just finds VDL==EOF.  Should look into
		 * whether there's a faster way to find the VDL.
		 */
#if 0
		off64_t next_data, next_hole;
		data = cur_off;
		do {
			next_data = next_hole = hole;
			rc = smb_fsop_next_alloc_range(ofile->f_cr,
			    ofile->f_node, &next_data, &next_hole);
			if (rc == 0) {
				hole = next_hole;
			}
		} while (rc == 0);
#else
		/* Assume no "holes" anywhere (VDL==EOF) */
		data = cur_off;
		hole = eof;
#endif
		DTRACE_PROBE2(range1, uint64_t, data, uint64_t, hole);
	}

	/*
	 * Loop terminates in the middle, continuing
	 * while (cur_off < end_off)
	 */
	for (;;) {
		/*
		 * We have a data region that covers (data, hole).
		 * It could be partially or entirely beyond the range
		 * the caller asked about (if so trim it).
		 */
		if (hole > end_off)
			hole = end_off;
		if (data > hole)
			data = hole;

		/*
		 * If cur_off < data encode a "hole" region
		 * (cur_off,data) and advance cur_off.
		 */
		if (cur_off < data) {
			rc = smb_mbc_encodef(fsctl->out_mbc, "qqll",
			    cur_off,
			    (data - cur_off),
			    0, // usage (hole)
			    0); // reserved
			cur_off = data;
			if (rc == 0)
				put_regions++;
			tot_regions++;
		}

		/*
		 * If cur_off < hole encode a "data" region
		 * (cur_off,hole) and advance cur_off.
		 */
		if (cur_off < hole) {
			rc = smb_mbc_encodef(fsctl->out_mbc, "qqll",
			    cur_off,
			    (hole - cur_off),
			    FILE_REGION_USAGE_VALID_CACHED_DATA,
			    0); // reserved
			cur_off = hole;
			if (rc == 0)
				put_regions++;
			tot_regions++;
		}

		/*
		 * Normal loop termination
		 */
		if (cur_off >= end_off)
			break;

		/*
		 * Get the next region (data, hole) starting on or after
		 * the current offset (cur_off).
		 */
		data = hole = cur_off;
		rc = smb_fsop_next_alloc_range(ofile->f_cr,
		    ofile->f_node, &data, &hole);
		switch (rc) {
		case 0:
			/* Found (data, hole) */
			break;
		case ENXIO:
			/*
			 * No more data after cur_off.
			 * Will encode one last hole.
			 */
			data = hole = eof;
			break;
		default:
			cmn_err(CE_NOTE, "smb_fsop_next_alloc_range: rc=%d",
			    rc);
			/* FALLTHROUGH */
		case ENOSYS:	/* FS does not support VOP_IOCTL... */
		case ENOTTY:	/* ... or _FIO_SEEK_DATA, _HOLE */
			data = cur_off;
			hole = eof;
			break;
		}
		DTRACE_PROBE2(range2, uint64_t, data, uint64_t, hole);
	}

	/*
	 * Overwrite the fixed part of the response with the
	 * final numbers of regions etc.
	 * Flags, TotalRegionEntryCount, RegionEntryCount, Reserved
	 */
	(void) smb_mbc_poke(fsctl->out_mbc, 0, "llll",
	    0, // flags
	    tot_regions,
	    put_regions,
	    0); // reserved

	if (put_regions < tot_regions)
		return (NT_STATUS_BUFFER_OVERFLOW);

	return (NT_STATUS_SUCCESS);
}