Nate Lawson c38b150ae4 New SCSI target emulator code
This code allows a user program to enable target mode on a SIM and
then emulate any number of devices (disks, tape drives, etc.)  All
decisions about device behavior (UA, CA, inquiry response) are left
to the usermode program and the kernel driver is merely a conduit
for CCBs.  This enables multiple concurrent target emulators, each
using its own backing store and IO model.

Also included is a user program that emulates a disk (RBC) using a
file as a backing store.  This provides functionality similar to
md(4) at the CAM layer.

Code has been tested on ahc(4) and should also work on isp(4) (and
other SIMs that gain target mode support).  It is a complete rewrite
of /sys/cam/scsi_target* and /usr/share/examples/scsi_target.

Design, comments from:	gibbs
Supported by:		Cryptography Research
Approved by:		re
2002-11-22 22:55:51 +00:00

665 lines
18 KiB
C

/*
* SCSI Disk Emulator
*
* Copyright (c) 2002 Nate Lawson.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification, immediately at the beginning of the file.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <stdio.h>
#include <stddef.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <aio.h>
#include <assert.h>
#include <sys/types.h>
#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_targetio.h>
#include "scsi_target.h"
typedef int targ_start_func(struct ccb_accept_tio *, struct ccb_scsiio *);
typedef void targ_done_func(struct ccb_accept_tio *, struct ccb_scsiio *,
io_ops);
struct targ_cdb_handlers {
u_int8_t cmd;
targ_start_func *start;
targ_done_func *done;
#define ILLEGAL_CDB 0xFF
};
static targ_start_func tcmd_inquiry;
static targ_start_func tcmd_req_sense;
static targ_start_func tcmd_rd_cap;
static targ_start_func tcmd_rdwr;
static targ_start_func tcmd_rdwr_decode;
static targ_done_func tcmd_rdwr_done;
static targ_start_func tcmd_null_ok;
static targ_start_func tcmd_illegal_req;
static int start_io(struct ccb_accept_tio *atio,
struct ccb_scsiio *ctio, int dir);
static int init_inquiry(u_int16_t req_flags, u_int16_t sim_flags);
static struct initiator_state *
tcmd_get_istate(u_int init_id);
static void cdb_debug(u_int8_t *cdb, const char *msg, ...);
static struct targ_cdb_handlers cdb_handlers[] = {
{ READ_10, tcmd_rdwr, tcmd_rdwr_done },
{ WRITE_10, tcmd_rdwr, tcmd_rdwr_done },
{ READ_6, tcmd_rdwr, tcmd_rdwr_done },
{ WRITE_6, tcmd_rdwr, tcmd_rdwr_done },
{ INQUIRY, tcmd_inquiry, NULL },
{ REQUEST_SENSE, tcmd_req_sense, NULL },
{ READ_CAPACITY, tcmd_rd_cap, NULL },
{ TEST_UNIT_READY, tcmd_null_ok, NULL },
{ START_STOP_UNIT, tcmd_null_ok, NULL },
{ SYNCHRONIZE_CACHE, tcmd_null_ok, NULL },
{ MODE_SENSE_6, tcmd_illegal_req, NULL },
{ MODE_SELECT_6, tcmd_illegal_req, NULL },
{ ILLEGAL_CDB, NULL, NULL }
};
static struct scsi_inquiry_data inq_data;
static struct initiator_state istates[MAX_INITIATORS];
extern int debug;
extern u_int32_t volume_size;
extern size_t sector_size;
extern size_t buf_size;
cam_status
tcmd_init(u_int16_t req_inq_flags, u_int16_t sim_inq_flags)
{
struct initiator_state *istate;
int i, ret;
/* Initialize our inquiry data */
ret = init_inquiry(req_inq_flags, sim_inq_flags);
if (ret != 0)
return (ret);
/* We start out life with a UA to indicate power-on/reset. */
for (i = 0; i < MAX_INITIATORS; i++) {
istate = tcmd_get_istate(i);
bzero(istate, sizeof(*istate));
istate->pending_ua = UA_POWER_ON;
}
return (0);
}
/* Caller allocates CTIO, sets its init_id
return 0 if done, 1 if more processing needed
on 0, caller sets SEND_STATUS */
int
tcmd_handle(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio, io_ops event)
{
static struct targ_cdb_handlers *last_cmd;
struct initiator_state *istate;
struct atio_descr *a_descr;
int ret;
warnx("tcmd_handle atio %p ctio %p atioflags %#x", atio, ctio,
atio->ccb_h.flags);
ret = 0;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
/* Do a full lookup if one-behind cache failed */
if (last_cmd == NULL || last_cmd->cmd != a_descr->cdb[0]) {
struct targ_cdb_handlers *h;
for (h = cdb_handlers; h->cmd != ILLEGAL_CDB; h++) {
if (a_descr->cdb[0] == h->cmd)
break;
}
last_cmd = h;
}
if (last_cmd->cmd == ILLEGAL_CDB) {
if (event != ATIO_WORK) {
warnx("no done func for %#x???", a_descr->cdb[0]);
abort();
}
/* Not found, return illegal request */
warnx("cdb %#x not handled", a_descr->cdb[0]);
tcmd_illegal_req(atio, ctio);
send_ccb((union ccb *)ctio, /*priority*/1);
return (0);
}
/* call completion and exit */
if (event != ATIO_WORK) {
if (last_cmd->done != NULL)
last_cmd->done(atio, ctio, event);
else
free_ccb((union ccb *)ctio);
return (1);
}
istate = tcmd_get_istate(ctio->init_id);
if (istate == NULL) {
tcmd_illegal_req(atio, ctio);
send_ccb((union ccb *)ctio, /*priority*/1);
return (0);
}
if (istate->pending_ca == 0 && istate->pending_ua != 0 &&
a_descr->cdb[0] != INQUIRY) {
tcmd_sense(ctio->init_id, ctio, SSD_KEY_UNIT_ATTENTION,
0x29, istate->pending_ua == UA_POWER_ON ? 1 : 2);
istate->pending_ca = CA_UNIT_ATTN;
if (debug) {
cdb_debug(a_descr->cdb, "UA active for %u: ",
atio->init_id);
}
send_ccb((union ccb *)ctio, /*priority*/1);
return (0);
}
/* Store current CA and UA for later */
istate->orig_ua = istate->pending_ua;
istate->orig_ca = istate->pending_ca;
/*
* As per SAM2, any command that occurs
* after a CA is reported, clears the CA. We must
* also clear the UA condition, if any, that caused
* the CA to occur assuming the UA is not for a
* persistent condition.
*/
istate->pending_ca = CA_NONE;
if (istate->orig_ca == CA_UNIT_ATTN)
istate->pending_ua = UA_NONE;
/* If we have a valid handler, call start or completion function */
if (last_cmd->cmd != ILLEGAL_CDB) {
ret = last_cmd->start(atio, ctio);
/* XXX hack */
if (last_cmd->start != tcmd_rdwr) {
a_descr->init_req += ctio->dxfer_len;
send_ccb((union ccb *)ctio, /*priority*/1);
}
}
return (ret);
}
static struct initiator_state *
tcmd_get_istate(u_int init_id)
{
if (init_id >= MAX_INITIATORS) {
warnx("illegal init_id %d, max %d", init_id, MAX_INITIATORS - 1);
return (NULL);
} else {
return (&istates[init_id]);
}
}
void
tcmd_sense(u_int init_id, struct ccb_scsiio *ctio, u_int8_t flags,
u_int8_t asc, u_int8_t ascq)
{
struct initiator_state *istate;
struct scsi_sense_data *sense;
/* Set our initiator's istate */
istate = tcmd_get_istate(init_id);
if (istate == NULL)
return;
istate->pending_ca |= CA_CMD_SENSE; /* XXX set instead of or? */
sense = &istate->sense_data;
bzero(sense, sizeof(*sense));
sense->error_code = SSD_CURRENT_ERROR;
sense->flags = flags;
sense->add_sense_code = asc;
sense->add_sense_code_qual = ascq;
sense->extra_len =
offsetof(struct scsi_sense_data, sense_key_spec[2]) -
offsetof(struct scsi_sense_data, extra_len);
/* Fill out the supplied CTIO */
if (ctio != NULL) {
/* No autosense yet
bcopy(sense, &ctio->sense_data, sizeof(*sense));
ctio->sense_len = sizeof(*sense); XXX
*/
ctio->ccb_h.flags &= ~CAM_DIR_MASK;
ctio->ccb_h.flags |= CAM_DIR_NONE | /* CAM_SEND_SENSE | */
CAM_SEND_STATUS;
ctio->dxfer_len = 0;
ctio->scsi_status = SCSI_STATUS_CHECK_COND;
}
}
void
tcmd_ua(u_int init_id, ua_types new_ua)
{
struct initiator_state *istate;
u_int start, end;
if (init_id == CAM_TARGET_WILDCARD) {
start = 0;
end = MAX_INITIATORS - 1;
} else {
start = end = init_id;
}
for (; start <= end; start++) {
istate = tcmd_get_istate(start);
if (istate == NULL)
break;
istate->pending_ua = new_ua;
}
}
static int
tcmd_inquiry(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
struct scsi_inquiry *inq;
struct atio_descr *a_descr;
struct initiator_state *istate;
struct scsi_sense_data *sense;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
inq = (struct scsi_inquiry *)a_descr->cdb;
if (debug)
cdb_debug(a_descr->cdb, "INQUIRY from %u: ", atio->init_id);
/*
* Validate the command. We don't support any VPD pages, so
* complain if EVPD or CMDDT is set.
*/
istate = tcmd_get_istate(ctio->init_id);
sense = &istate->sense_data;
if ((inq->byte2 & SI_EVPD) != 0) {
tcmd_illegal_req(atio, ctio);
sense->sense_key_spec[0] = SSD_SCS_VALID | SSD_FIELDPTR_CMD |
SSD_BITPTR_VALID | /*bit value*/1;
sense->sense_key_spec[1] = 0;
sense->sense_key_spec[2] =
offsetof(struct scsi_inquiry, byte2);
} else if (inq->page_code != 0) {
tcmd_illegal_req(atio, ctio);
sense->sense_key_spec[0] = SSD_SCS_VALID | SSD_FIELDPTR_CMD;
sense->sense_key_spec[1] = 0;
sense->sense_key_spec[2] =
offsetof(struct scsi_inquiry, page_code);
} else {
bcopy(&inq_data, ctio->data_ptr, sizeof(inq_data));
ctio->dxfer_len = inq_data.additional_length + 4;
ctio->dxfer_len = min(ctio->dxfer_len,
SCSI_CDB6_LEN(inq->length));
ctio->ccb_h.flags |= CAM_DIR_IN | CAM_SEND_STATUS;
ctio->scsi_status = SCSI_STATUS_OK;
}
return (0);
}
/* Initialize the inquiry response structure with the requested flags */
static int
init_inquiry(u_int16_t req_flags, u_int16_t sim_flags)
{
struct scsi_inquiry_data *inq;
inq = &inq_data;
bzero(inq, sizeof(*inq));
inq->device = T_DIRECT | (SID_QUAL_LU_CONNECTED << 5);
inq->version = SCSI_REV_SPC; /* was 2 */
/*
* XXX cpi.hba_inquiry doesn't support Addr16 so we give the
* user what they want if they ask for it.
*/
if ((req_flags & SID_Addr16) != 0) {
sim_flags |= SID_Addr16;
warnx("Not sure SIM supports Addr16 but enabling it anyway");
}
/* Advertise only what the SIM can actually support */
req_flags &= sim_flags;
scsi_ulto2b(req_flags, &inq->reserved[1]);
inq->response_format = 2; /* SCSI2 Inquiry Format */
inq->additional_length = SHORT_INQUIRY_LENGTH -
offsetof(struct scsi_inquiry_data, additional_length);
bcopy("FreeBSD ", inq->vendor, SID_VENDOR_SIZE);
bcopy("Emulated Disk ", inq->product, SID_PRODUCT_SIZE);
bcopy("0.1 ", inq->revision, SID_REVISION_SIZE);
return (0);
}
static int
tcmd_req_sense(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
struct scsi_request_sense *rsense;
struct scsi_sense_data *sense;
struct initiator_state *istate;
size_t dlen;
struct atio_descr *a_descr;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
rsense = (struct scsi_request_sense *)a_descr->cdb;
istate = tcmd_get_istate(ctio->init_id);
sense = &istate->sense_data;
if (debug) {
cdb_debug(a_descr->cdb, "REQ SENSE from %u: ", atio->init_id);
warnx("Sending sense: %#x %#x %#x", sense->flags,
sense->add_sense_code, sense->add_sense_code_qual);
}
if (istate->orig_ca == 0) {
tcmd_sense(ctio->init_id, NULL, SSD_KEY_NO_SENSE, 0, 0);
warnx("REQUEST SENSE from %u but no pending CA!",
ctio->init_id);
}
bcopy(sense, ctio->data_ptr, sizeof(struct scsi_sense_data));
dlen = offsetof(struct scsi_sense_data, extra_len) +
sense->extra_len + 1;
ctio->dxfer_len = min(dlen, SCSI_CDB6_LEN(rsense->length));
ctio->ccb_h.flags |= CAM_DIR_IN | CAM_SEND_STATUS;
ctio->scsi_status = SCSI_STATUS_OK;
return (0);
}
static int
tcmd_rd_cap(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
struct scsi_read_capacity_data *srp;
struct atio_descr *a_descr;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
srp = (struct scsi_read_capacity_data *)ctio->data_ptr;
if (debug) {
cdb_debug(a_descr->cdb, "READ CAP from %u (%u, %u): ",
atio->init_id, volume_size - 1, sector_size);
}
bzero(srp, sizeof(*srp));
scsi_ulto4b(volume_size - 1, srp->addr);
scsi_ulto4b(sector_size, srp->length);
ctio->dxfer_len = sizeof(*srp);
ctio->ccb_h.flags |= CAM_DIR_IN | CAM_SEND_STATUS;
ctio->scsi_status = SCSI_STATUS_OK;
return (0);
}
static int
tcmd_rdwr(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
struct atio_descr *a_descr;
struct ctio_descr *c_descr;
int ret;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
c_descr = (struct ctio_descr *)ctio->ccb_h.targ_descr;
/* Command needs to be decoded */
if ((a_descr->flags & CAM_DIR_MASK) == CAM_DIR_RESV) {
if (debug)
warnx("Calling rdwr_decode");
ret = tcmd_rdwr_decode(atio, ctio);
if (ret == 0) {
send_ccb((union ccb *)ctio, /*priority*/1);
return (0);
}
}
ctio->ccb_h.flags |= a_descr->flags;
/* Call appropriate work function */
if ((a_descr->flags & CAM_DIR_IN) != 0) {
ret = start_io(atio, ctio, CAM_DIR_IN);
if (debug)
warnx("Starting DIR_IN @%lld:%u", c_descr->offset,
a_descr->targ_req);
} else {
ret = start_io(atio, ctio, CAM_DIR_OUT);
if (debug)
warnx("Starting DIR_OUT @%lld:%u", c_descr->offset,
a_descr->init_req);
}
return (ret);
}
static int
tcmd_rdwr_decode(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
u_int32_t blkno, count;
struct atio_descr *a_descr;
u_int8_t *cdb;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
cdb = a_descr->cdb;
if (debug)
cdb_debug(cdb, "R/W from %u: ", atio->init_id);
if (cdb[0] == READ_6 || cdb[0] == WRITE_6) {
struct scsi_rw_6 *rw_6 = (struct scsi_rw_6 *)cdb;
blkno = scsi_3btoul(rw_6->addr);
count = rw_6->length;
} else {
struct scsi_rw_10 *rw_10 = (struct scsi_rw_10 *)cdb;
blkno = scsi_4btoul(rw_10->addr);
count = scsi_2btoul(rw_10->length);
}
if (blkno + count > volume_size) {
warnx("Attempt to access past end of volume");
tcmd_sense(ctio->init_id, ctio,
SSD_KEY_ILLEGAL_REQUEST, 0x21, 0);
return (0);
}
/* Get an (overall) data length and set direction */
a_descr->base_off = ((off_t)blkno) * sector_size;
a_descr->total_len = count * sector_size;
if (a_descr->total_len == 0) {
if (debug)
warnx("r/w 0 blocks @ blkno %u", blkno);
tcmd_null_ok(atio, ctio);
return (0);
} else if (cdb[0] == WRITE_6 || cdb[0] == WRITE_10) {
a_descr->flags |= CAM_DIR_OUT;
if (debug)
warnx("write %u blocks @ blkno %u", count, blkno);
} else {
a_descr->flags |= CAM_DIR_IN;
if (debug)
warnx("read %u blocks @ blkno %u", count, blkno);
}
return (1);
}
static int
start_io(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio, int dir)
{
struct atio_descr *a_descr;
struct ctio_descr *c_descr;
int ret;
/* Set up common structures */
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
c_descr = (struct ctio_descr *)ctio->ccb_h.targ_descr;
if (dir == CAM_DIR_IN) {
c_descr->offset = a_descr->base_off + a_descr->targ_req;
ctio->dxfer_len = a_descr->total_len - a_descr->targ_req;
} else {
c_descr->offset = a_descr->base_off + a_descr->init_req;
ctio->dxfer_len = a_descr->total_len - a_descr->init_req;
}
ctio->dxfer_len = min(ctio->dxfer_len, buf_size);
assert(ctio->dxfer_len >= 0);
c_descr->aiocb.aio_offset = c_descr->offset;
c_descr->aiocb.aio_nbytes = ctio->dxfer_len;
/* If DIR_IN, start read from target, otherwise begin CTIO xfer. */
ret = 1;
if (dir == CAM_DIR_IN) {
if (aio_read(&c_descr->aiocb) < 0)
err(1, "aio_read"); /* XXX */
a_descr->targ_req += ctio->dxfer_len;
if (a_descr->targ_req == a_descr->total_len) {
ctio->ccb_h.flags |= CAM_SEND_STATUS;
ctio->scsi_status = SCSI_STATUS_OK;
ret = 0;
}
} else {
if (a_descr->targ_ack == a_descr->total_len)
tcmd_null_ok(atio, ctio);
a_descr->init_req += ctio->dxfer_len;
if (a_descr->init_req == a_descr->total_len &&
ctio->dxfer_len > 0) {
/*
* If data phase done, remove atio from workq.
* The completion handler will call work_atio to
* send the final status.
*/
ret = 0;
}
send_ccb((union ccb *)ctio, /*priority*/1);
}
return (ret);
}
static void
tcmd_rdwr_done(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio,
io_ops event)
{
struct atio_descr *a_descr;
struct ctio_descr *c_descr;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
c_descr = (struct ctio_descr *)ctio->ccb_h.targ_descr;
switch (event) {
case AIO_DONE:
if (aio_return(&c_descr->aiocb) < 0) {
warn("aio_return error");
/* XXX */
tcmd_sense(ctio->init_id, ctio,
SSD_KEY_MEDIUM_ERROR, 0, 0);
send_ccb((union ccb *)ctio, /*priority*/1);
break;
}
a_descr->targ_ack += ctio->dxfer_len;
if ((a_descr->flags & CAM_DIR_IN) != 0) {
if (debug)
warnx("sending CTIO for AIO read");
a_descr->init_req += ctio->dxfer_len;
send_ccb((union ccb *)ctio, /*priority*/1);
} else {
/* Use work function to send final status */
if (a_descr->init_req == a_descr->total_len)
work_atio(atio);
if (debug)
warnx("AIO done freeing CTIO");
free_ccb((union ccb *)ctio);
}
break;
case CTIO_DONE:
if (ctio->ccb_h.status != CAM_REQ_CMP) {
/* XXX */
errx(1, "CTIO failed, status %#x", ctio->ccb_h.status);
}
a_descr->init_ack += ctio->dxfer_len;
if ((a_descr->flags & CAM_DIR_MASK) == CAM_DIR_OUT &&
ctio->dxfer_len > 0) {
if (debug)
warnx("sending AIO for CTIO write");
a_descr->targ_req += ctio->dxfer_len;
if (aio_write(&c_descr->aiocb) < 0)
err(1, "aio_write"); /* XXX */
} else {
if (debug)
warnx("CTIO done freeing CTIO");
free_ccb((union ccb *)ctio);
}
break;
default:
warnx("Unknown completion code %d", event);
abort();
/* NOTREACHED */
}
}
/* Simple ok message used by TUR, SYNC_CACHE, etc. */
static int
tcmd_null_ok(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
if (debug) {
struct atio_descr *a_descr;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
cdb_debug(a_descr->cdb, "Sending null ok to %u : ", atio->init_id);
}
ctio->dxfer_len = 0;
ctio->ccb_h.flags &= ~CAM_DIR_MASK;
ctio->ccb_h.flags |= CAM_DIR_NONE | CAM_SEND_STATUS;
ctio->scsi_status = SCSI_STATUS_OK;
return (0);
}
/* Simple illegal request message used by MODE SENSE, etc. */
static int
tcmd_illegal_req(struct ccb_accept_tio *atio, struct ccb_scsiio *ctio)
{
if (debug) {
struct atio_descr *a_descr;
a_descr = (struct atio_descr *)atio->ccb_h.targ_descr;
cdb_debug(a_descr->cdb, "Sending ill req to %u: ", atio->init_id);
}
tcmd_sense(atio->init_id, ctio, SSD_KEY_ILLEGAL_REQUEST,
/*asc*/0x24, /*ascq*/0);
return (0);
}
static void
cdb_debug(u_int8_t *cdb, const char *msg, ...)
{
char msg_buf[512];
int len;
va_list ap;
va_start(ap, msg);
vsnprintf(msg_buf, sizeof(msg_buf), msg, ap);
va_end(ap);
len = strlen(msg_buf);
scsi_cdb_string(cdb, msg_buf + len, sizeof(msg_buf) - len);
warnx("%s", msg_buf);
}