usr.sbin/autofs: Cleanup workaround code for a VFS bug
[dragonfly.git] / lib / libcam / cam_cdbparse.3
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1.\"
2.\" Copyright (c) 1998 Kenneth D. Merry.
3.\" All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
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8.\" 1. Redistributions of source code must retain the above copyright
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10.\" 2. Redistributions in binary form must reproduce the above copyright
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12.\" documentation and/or other materials provided with the distribution.
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14.\" derived from this software without specific prior written permission.
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17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26.\" SUCH DAMAGE.
27.\"
28.\" $FreeBSD: src/lib/libcam/cam_cdbparse.3,v 1.3.2.11 2002/12/29 16:35:35 schweikh Exp $
29.\"
30.\" This man page borrows heavily from the old scsi(3) man page, which had
31.\" the following copyright:
32.\"
33.\" Copyright (c) 1994 HD Associates (hd@world.std.com)
34.\" All rights reserved.
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36.\" Redistribution and use in source and binary forms, with or without
37.\" modification, are permitted provided that the following conditions
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53.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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56.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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62.\"
984263bc 63.Dd October 13, 1998
984263bc 64.Dt CAM_CDBPARSE 3
fb5b3747 65.Os
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66.Sh NAME
67.Nm csio_build ,
68.Nm csio_build_visit ,
69.Nm csio_decode ,
70.Nm csio_decode_visit ,
71.Nm buff_decode ,
72.Nm buff_decode_visit ,
73.Nm csio_encode ,
74.Nm csio_encode_visit ,
75.Nm buff_encode_visit
76.Nd CAM user library SCSI buffer parsing routines
77.Sh LIBRARY
78.Lb libcam
79.Sh SYNOPSIS
80.In stdio.h
81.In camlib.h
82.Ft int
83.Fo csio_build
84.Fa "struct ccb_scsiio *csio"
85.Fa "u_int8_t *data_ptr"
86.Fa "u_int32_t dxfer_len"
87.Fa "u_int32_t flags"
88.Fa "int retry_count"
89.Fa "int timeout"
5adc1304 90.Fa "const char *cmd_spec"
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91.Fa "..."
92.Fc
93.Ft int
94.Fo csio_build_visit
95.Fa "struct ccb_scsiio *csio"
96.Fa "u_int8_t *data_ptr"
97.Fa "u_int32_t dxfer_len"
98.Fa "u_int32_t flags"
99.Fa "int retry_count"
100.Fa "int timeout"
5adc1304 101.Fa "const char *cmd_spec"
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102.Fa "int (*arg_get)(void *hook, char *field_name)"
103.Fa "void *gethook"
104.Fc
105.Ft int
106.Fo csio_decode
107.Fa "struct ccb_scsiio *csio"
5adc1304 108.Fa "const char *fmt"
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109.Fa "..."
110.Fc
111.Ft int
112.Fo csio_decode_visit
113.Fa "struct ccb_scsiio *csio"
5adc1304 114.Fa "const char *fmt"
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115.Fa "void (*arg_put)(void *hook"
116.Fa "int letter"
117.Fa "void *val"
118.Fa "int count"
119.Fa "char *name)"
120.Fa "void *puthook"
121.Fc
122.Ft int
123.Fo buff_decode
124.Fa "u_int8_t *buff"
125.Fa "size_t len"
5adc1304 126.Fa "const char *fmt"
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127.Fa "..."
128.Fc
129.Ft int
130.Fo buff_decode_visit
131.Fa "u_int8_t *buff"
132.Fa "size_t len"
5adc1304 133.Fa "const char *fmt"
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134.Fa "void (*arg_put)(void *, int, void *, int, char *)"
135.Fa "void *puthook"
136.Fc
137.Ft int
138.Fo csio_encode
139.Fa "struct ccb_scsiio *csio"
5adc1304 140.Fa "const char *fmt"
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141.Fa "..."
142.Fc
143.Ft int
144.Fo csio_encode_visit
145.Fa "struct ccb_scsiio *csio"
5adc1304 146.Fa "const char *fmt"
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147.Fa "int (*arg_get)(void *hook, char *field_name)"
148.Fa "void *gethook"
149.Fc
150.Ft int
151.Fo buff_encode_visit
152.Fa "u_int8_t *buff"
153.Fa "size_t len"
5adc1304 154.Fa "const char *fmt"
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155.Fa "int (*arg_get)(void *hook, char *field_name)"
156.Fa "void *gethook"
157.Fc
158.Sh DESCRIPTION
159The CAM buffer/CDB encoding and decoding routines provide a relatively easy
160migration path for userland
161.Tn SCSI
162applications written with the similarly-named
163.Va scsireq_ Ns *
164functions from the old
165.Fx
166.Tn SCSI
167layer.
168.Pp
169These functions may be used in new applications, but users may find it
170easier to use the various SCSI CCB building functions included with the
171.Xr cam 3
172library. (e.g.\&
173.Fn cam_fill_csio ,
174.Fn scsi_start_stop ,
175and
176.Fn scsi_read_write )
177.Pp
178.Fn csio_build
179builds up a
180.Va ccb_scsiio
181structure based on the information provided in
182the variable argument list.
183It gracefully handles a NULL
184.Fa data_ptr
185argument passed to it.
186.Pp
187.Fa dxfer_len
188is the length of the data phase; the data transfer direction is
189determined by the
190.Fa flags
191argument.
192.Pp
193.Fa data_ptr
194is the data buffer used during the
195.Tn SCSI
196data phase. If no data is to be
197transferred for the
198.Tn SCSI
199command in question, this should be set to NULL. If there is data to
200transfer for the command, this buffer must be at least
201.Fa dxfer_len
202long.
203.Pp
204.Fa flags
205are the flags defined in
44cb301e 206.In bus/cam/cam_ccb.h :
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207.Bd -literal
208/* Common CCB header */
209/* CAM CCB flags */
210typedef enum {
211 CAM_CDB_POINTER = 0x00000001,/* The CDB field is a pointer */
212 CAM_QUEUE_ENABLE = 0x00000002,/* SIM queue actions are enabled */
213 CAM_CDB_LINKED = 0x00000004,/* CCB contains a linked CDB */
214 CAM_SCATTER_VALID = 0x00000010,/* Scatter/gather list is valid */
215 CAM_DIS_AUTOSENSE = 0x00000020,/* Disable autosense feature */
216 CAM_DIR_RESV = 0x00000000,/* Data direction (00:reserved) */
217 CAM_DIR_IN = 0x00000040,/* Data direction (01:DATA IN) */
218 CAM_DIR_OUT = 0x00000080,/* Data direction (10:DATA OUT) */
219 CAM_DIR_NONE = 0x000000C0,/* Data direction (11:no data) */
220 CAM_DIR_MASK = 0x000000C0,/* Data direction Mask */
221 CAM_SOFT_RST_OP = 0x00000100,/* Use Soft reset alternative */
222 CAM_ENG_SYNC = 0x00000200,/* Flush resid bytes on complete */
223 CAM_DEV_QFRZDIS = 0x00000400,/* Disable DEV Q freezing */
224 CAM_DEV_QFREEZE = 0x00000800,/* Freeze DEV Q on execution */
225 CAM_HIGH_POWER = 0x00001000,/* Command takes a lot of power */
226 CAM_SENSE_PTR = 0x00002000,/* Sense data is a pointer */
227 CAM_SENSE_PHYS = 0x00004000,/* Sense pointer is physical addr*/
228 CAM_TAG_ACTION_VALID = 0x00008000,/* Use the tag action in this ccb*/
229 CAM_PASS_ERR_RECOVER = 0x00010000,/* Pass driver does err. recovery*/
230 CAM_DIS_DISCONNECT = 0x00020000,/* Disable disconnect */
231 CAM_SG_LIST_PHYS = 0x00040000,/* SG list has physical addrs. */
232 CAM_MSG_BUF_PHYS = 0x00080000,/* Message buffer ptr is physical*/
233 CAM_SNS_BUF_PHYS = 0x00100000,/* Autosense data ptr is physical*/
234 CAM_DATA_PHYS = 0x00200000,/* SG/Buffer data ptrs are phys. */
235 CAM_CDB_PHYS = 0x00400000,/* CDB pointer is physical */
236 CAM_ENG_SGLIST = 0x00800000,/* SG list is for the HBA engine */
237
238/* Phase cognizant mode flags */
239 CAM_DIS_AUTOSRP = 0x01000000,/* Disable autosave/restore ptrs */
240 CAM_DIS_AUTODISC = 0x02000000,/* Disable auto disconnect */
241 CAM_TGT_CCB_AVAIL = 0x04000000,/* Target CCB available */
242 CAM_TGT_PHASE_MODE = 0x08000000,/* The SIM runs in phase mode */
243 CAM_MSGB_VALID = 0x20000000,/* Message buffer valid */
244 CAM_STATUS_VALID = 0x40000000,/* Status buffer valid */
245 CAM_DATAB_VALID = 0x80000000,/* Data buffer valid */
246
247/* Host target Mode flags */
248 CAM_TERM_IO = 0x20000000,/* Terminate I/O Message sup. */
249 CAM_DISCONNECT = 0x40000000,/* Disconnects are mandatory */
250 CAM_SEND_STATUS = 0x80000000,/* Send status after data phase */
251} ccb_flags;
252.Ed
253.Pp
254Multiple flags should be ORed together. Any of the CCB flags may be used,
255although it is worth noting several important ones here:
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256.Bl -tag -width CAM_PASS_ERR_RECOVER
257.It Dv CAM_DIR_IN
258This indicates that the operation in question is a read operation. i.e.,
259data is being read from the
260.Tn SCSI
261device to the user-supplied buffer.
262.It Dv CAM_DIR_OUT
263This indicates that the operation is a write operation. i.e. data is being
264written from the user-supplied buffer to the device.
265.It Dv CAM_DIR_NONE
266This indicates that there is no data to be transferred for this command.
267.It Dv CAM_DEV_QFRZDIS
268This flag disables device queue freezing as an error recovery mechanism.
269.It Dv CAM_PASS_ERR_RECOVER
270This flag tells the
271.Xr pass 4
272driver to enable error recovery. The default is to not perform error
273recovery, which means that the retry count won't be honored without this
274flag, among other things.
275.It Dv CAM_DATA_PHYS
276This indicates that the address contained in
277.Fa data_ptr
278is a physical address, not a virtual address.
279.El
280.Pp
281The
282.Fa retry_count
283tells the kernel how many times to retry the command in question. The
284retry count is ignored unless the
285.Xr pass 4
286driver is told to enable error recovery via the
287.Dv CAM_PASS_ERR_RECOVER
288flag.
289.Pp
290The
291.Fa timeout
292tells the kernel how long to wait for the given command to complete. If
293the timeout expires and the command hasn't completed, the CCB will be
294returned from the kernel with an appropriate error status.
295.Pp
296.Fa cmd_spec
297is a CDB format specifier used to build up the SCSI CDB.
298This text string is made up of a list of field specifiers. Field
299specifiers specify the value for each CDB field (including indicating
300that the value be taken from the next argument in the
301variable argument list), the width
302of the field in bits or bytes, and an optional name. White space is
303ignored, and the pound sign ('#') introduces a comment that ends at the
304end of the current line.
305.Pp
306The optional name is the first part of a field specifier and
307is in curly braces. The text in curly braces in this example are
308the names:
309.Dl "{PS} v:b1 {Reserved} 0:b1 {Page Code} v:b6 # Mode select page"
310.Pp
311This field specifier has two one bit fields and one six bit field.
312The second one bit field is the constant value 0 and the first
313one bit field and the six bit field are taken from the variable
314argument list.
315Multi byte fields are swapped into the SCSI byte order in the
316CDB and white space is ignored.
317.Pp
318When the field is a hex value or the letter v, (e.g.,
319.Fa "1A"
320or
321.Fa "v" )
322then a single byte value
323is copied to the next unused byte of the CDB.
324When the letter
325.Fa v
326is used the next integer argument is taken from the variable argument list
327and that value used.
328.Pp
329A constant hex value followed by a field width specifier or the letter
330.Fa v
331followed by a field width specifier (e.g.,
332.Fa 3:4 ,
333.Fa 3:b4 ,
334.Fa 3:i3 ,
335.Fa v:i3 )
336specifies a field of a given bit or byte width.
337Either the constant value or (for the V specifier) the next integer value from
338the variable argument list is copied to the next unused
339bits or bytes of the CDB.
340.Pp
341A decimal number or the letter
342.Fa b
343followed by a decimal number field width indicates a bit field of that width.
344The bit fields are packed as tightly as possible beginning with the
345high bit (so that it reads the same as the SCSI spec), and a new byte of
346the CDB is started whenever a byte fills completely or when an
347.Fa i
348field is encountered.
349.Pp
350A field width specifier consisting of the letter
351.Fa i
352followed by either
3531, 2, 3 or 4 indicates a 1, 2, 3 or 4 byte integral value that must
354be swapped into SCSI byte order (MSB first).
355.Pp
356For the
357.Fa v
358field specifier the next integer argument is taken from the variable argument
359list and that value is used swapped into SCSI byte order.
360.Pp
361.Fn csio_build_visit
362operates similarly to
363.Fn csio_build ,
364except that the values to substitute for variable arguments in
365.Fa cmd_spec
366are retrieved via the
367.Fn arg_get
368function passed in to
369.Fn csio_build_visit
370instead of via
371.Xr stdarg 3 .
372The
373.Fn arg_get
374function takes two arguments:
375.Bl -tag -width field_name
376.It Fa gethook
377is passed into the
378.Fn arg_get
379function at each invocation. This enables the
380.Fn arg_get
381function to keep some state in between calls without using global or static
382variables.
383.It Fa field_name
384is the field name supplied in
385.Fa fmt ,
386if any.
387.El
388.Pp
389.Fn csio_decode
390is used to decode information from the data in phase of the SCSI
391transfer.
392.Pp
393The decoding is similar to
394the command specifier processing of
395.Fn csio_build
396except that the data is extracted from the data pointed to by
397.Fa csio->data_ptr .
398The stdarg list should be pointers to integers instead of integer
399values.
400A seek field type and a suppression modifier are added.
401The
402.Fa *
403suppression modifier (e.g.,
404.Fa *i3
405or
406.Fa *b4 )
407suppresses assignment from the field and can be used to skip
408over bytes or bits in the data, without having to copy
409them to a dummy variable in the arg list.
410.Pp
411The seek field type
412.Fa s
413permits you to skip over data.
414This seeks to an absolute position
415.Pq Fa s3
416or a relative position
417.Pq Fa s+3
418in the data, based on whether or not the presence of the '+' sign.
419The seek value can be specified as
420.Fa v
421and the next integer value from the argument list will be
422used as the seek value.
423.Pp
424.Fn csio_decode_visit
425operates like
426.Fn csio_decode
427except that instead of placing the decoded contents of the buffer in
428variadic arguments, the decoded buffer contents are returned to the user
429via the
430.Fn arg_put
431function that is passed in.
432The
433.Fn arg_put
434function takes several arguments:
435.Bl -tag -width letter
436.It Fa hook
437The "hook" is a mechanism to allow the
438.Fn arg_put
439function to save state in between calls.
440.It Fa letter
441is the letter describing the format of the argument being passed into the
442function.
443.It Fa val
444is a void pointer to the value being passed into the function.
445.It Fa count
446is the size of the value being passed into the
447.Fn arg_put
448function. The argument format determines the unit of measure.
449.It Fa name
450This is a text description of the field, if one was provided in the
451.Fa fmt .
452.El
453.Pp
454.Fn buff_decode
455decodes an arbitrary data buffer using the method
456described above for
457.Fn csio_decode .
458.Pp
459.Fn buff_decode_visit
460decodes an arbitrary data buffer using the method described above for
461.Fn csio_decode_visit .
462.Pp
463.Fn csio_encode
464encodes the
465.Fa data_ptr
466portion (not the CDB!) of a
467.Va ccb_scsiio
468structure, using the method described above for
469.Fn csio_build .
470.Pp
471.Fn csio_encode_visit
472encodes the
473.Fa data_ptr
474portion (not the CDB!) of a
475.Va ccb_scsiio
476structure, using the method described above for
477.Fn csio_build_visit .
478.Pp
479.Fn buff_encode_visit
480encodes an arbitrary data pointer, using the method described
481above for
482.Fn csio_build_visit .
483.Sh RETURN VALUES
484.Fn csio_build ,
485.Fn csio_build_visit ,
486.Fn csio_encode ,
487.Fn csio_encode_visit ,
488and
489.Fn buff_encode_visit
490return the number of fields processed.
491.Pp
492.Fn csio_decode ,
493.Fn csio_decode_visit ,
494.Fn buff_decode ,
495and
496.Fn buff_decode_visit
497return the number of assignments performed.
498.Sh SEE ALSO
499.Xr cam 3 ,
500.Xr pass 4 ,
501.Xr camcontrol 8
502.Sh HISTORY
503The CAM versions of these functions are based upon similar functions
504implemented for the old
505.Fx
506.Tn SCSI
507layer. The encoding/decoding functions in the old
508.Tn SCSI
509code were written by Peter Dufault.
510.Pp
511Many systems have comparable interfaces to permit a user to construct a
512SCSI command in user space.
513.Pp
514The old
515.Va scsireq
516data structure was almost identical to the SGI /dev/scsi data
517structure. If anyone knows the name of the authors it should
518go here; Peter Dufault first read about it in a 1989 Sun Expert magazine.
519.Pp
520The new CCB data structures are derived from the CAM-2 and CAM-3
521specifications.
522.Pp
523.An Peter Dufault
524implemented a clone of SGI's interface in
525.Bx 386
526that
527led to the original
528.Fx
529.Tn SCSI
530library and the related kernel ioctl.
531If anyone needs that for compatibility contact dufault@hda.com.
532.Sh AUTHORS
533Kenneth Merry implemented the CAM versions of these encoding and decoding
534functions. This current work is based upon earlier work by Peter Dufault.
535.Sh BUGS
536There should probably be a function that encodes both the CDB and the data
537buffer portions of a
538.Tn SCSI
539CCB. I discovered this while implementing the arbitrary command execution
540code in
541.Xr camcontrol 8 ,
542but I haven't yet had time to implement such a function.
543.Pp
544Some of the CCB flag descriptions really don't belong here. Rather they
545belong in a generic CCB man page. Since that man page hasn't yet been
546written, the shorter descriptions here will have to suffice.