sys/sys/mount.h: Add fsidcmp()
[dragonfly.git] / lib / libcam / cam.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
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\" notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\" notice, this list of conditions and the following disclaimer in the
12.\" documentation and/or other materials provided with the distribution.
13.\" 3. The name of the author may not be used to endorse or promote products
14.\" derived from this software without specific prior written permission.
15.\"
16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.3,v 1.5.2.6 2001/12/17 10:08:28 ru Exp $
29.\"
30.Dd October 10, 1998
984263bc 31.Dt CAM 3
fb5b3747 32.Os
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33.Sh NAME
34.Nm cam_open_device ,
35.Nm cam_open_spec_device ,
36.Nm cam_open_btl ,
37.Nm cam_open_pass ,
38.Nm cam_close_device ,
39.Nm cam_close_spec_device ,
40.Nm cam_getccb ,
41.Nm cam_send_ccb ,
42.Nm cam_freeccb ,
43.Nm cam_path_string ,
44.Nm cam_device_dup ,
45.Nm cam_device_copy ,
46.Nm cam_get_device
47.Nd CAM user library
48.Sh LIBRARY
49.Lb libcam
50.Sh SYNOPSIS
51.In stdio.h
52.In camlib.h
53.Ft struct cam_device *
54.Fo cam_open_device
55.Fa "const char *path"
56.Fa "int flags"
57.Fc
58.Ft struct cam_device *
59.Fo cam_open_spec_device
60.Fa "const char *dev_name"
61.Fa "int unit"
62.Fa "int flags"
63.Fa "struct cam_device *device"
64.Fc
65.Ft struct cam_device *
66.Fo cam_open_btl
67.Fa "path_id_t path_id"
68.Fa "target_id_t target_id"
69.Fa "lun_id_t target_lun"
70.Fa "int flags"
71.Fa "struct cam_device *device"
72.Fc
73.Ft struct cam_device *
74.Fo cam_open_pass
75.Fa "const char *path"
76.Fa "int flags"
77.Fa "struct cam_device *device"
78.Fc
79.Ft void
80.Fo cam_close_device
81.Fa "struct cam_device *dev"
82.Fc
83.Ft void
84.Fo cam_close_spec_device
85.Fa "struct cam_device *dev"
86.Fc
87.Ft union ccb *
88.Fo cam_getccb
89.Fa "struct cam_device *dev"
90.Fc
91.Ft int
92.Fo cam_send_ccb
93.Fa "struct cam_device *device"
94.Fa "union ccb *ccb"
95.Fc
96.Ft void
97.Fo cam_freeccb
98.Fa "union ccb *ccb"
99.Fc
100.Ft char *
101.Fo cam_path_string
102.Fa "struct cam_device *dev"
103.Fa "char *str"
104.Fa "int len"
105.Fc
106.Ft struct cam_device *
107.Fo cam_device_dup
108.Fa "struct cam_device *device"
109.Fc
110.Ft void
111.Fo cam_device_copy
112.Fa "struct cam_device *src"
113.Fa "struct cam_device *dst"
114.Fc
115.Ft int
116.Fo cam_get_device
117.Fa "const char *path"
118.Fa "char *dev_name"
119.Fa "int devnamelen"
120.Fa "int *unit"
121.Fc
122.Sh DESCRIPTION
123The CAM library consists of a number of functions designed to aid in
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124programming with the CAM subsystem.
125This man page covers the basic set of library functions.
126More functions are documented in the man pages listed below.
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127.Pp
128Many of the CAM library functions use the
129.Va cam_device
130structure:
131.Bd -literal
132struct cam_device {
133 char device_path[MAXPATHLEN+1];/*
134 * Pathname of the
135 * device given by the
136 * user. This may be
137 * null if the user
138 * states the device
139 * name and unit number
140 * separately.
141 */
142 char given_dev_name[DEV_IDLEN+1];/*
143 * Device name given by
144 * the user.
145 */
146 u_int32_t given_unit_number; /*
147 * Unit number given by
148 * the user.
149 */
150 char device_name[DEV_IDLEN+1];/*
151 * Name of the device,
152 * e.g. 'pass'
153 */
154 u_int32_t dev_unit_num; /* Unit number of the passthrough
155 * device associated with this
156 * particular device.
157 */
158
159 char sim_name[SIM_IDLEN+1];/*
7efec73e 160 * Controller name, e.g.'ahci'
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161 */
162 u_int32_t sim_unit_number; /* Controller unit number */
163 u_int32_t bus_id; /* Controller bus number */
164 lun_id_t target_lun; /* Logical Unit Number */
165 target_id_t target_id; /* Target ID */
166 path_id_t path_id; /* System SCSI bus number */
167 u_int16_t pd_type; /* type of peripheral device */
168 struct scsi_inquiry_data inq_data; /* SCSI Inquiry data */
169 u_int8_t serial_num[252]; /* device serial number */
170 u_int8_t serial_num_len; /* length of the serial number */
171 u_int8_t sync_period; /* Negotiated sync period */
172 u_int8_t sync_offset; /* Negotiated sync offset */
173 u_int8_t bus_width; /* Negotiated bus width */
174 int fd; /* file descriptor for device */
175};
176.Ed
177.Pp
178.Fn cam_open_device
179takes as arguments a string describing the device it is to open, and
180.Ar flags
181suitable for passing to
182.Xr open 2 .
183The "path" passed in may actually be most any type of string that contains
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184a device name and unit number to be opened.
185The string will be parsed by
984263bc 186.Fn cam_get_device
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187into a device name and unit number.
188Once the device name and unit number
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189are determined, a lookup is performed to determine the passthrough device
190that corresponds to the given device.
191.Fn cam_open_device
192is rather simple to use, but it isn't really suitable for general use
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193because its behavior isn't necessarily deterministic.
194Programmers writing
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195new applications should make the extra effort to use one of the other open
196routines documented below.
197.Pp
198.Fn cam_open_spec_device
199opens the
200.Xr pass 4
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201device that corresponds to the device name and unit number passed in.
202The
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203.Ar flags
204should be flags suitable for passing to
205.Xr open 2 .
206The
207.Ar device
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208argument is optional.
209The user may supply pre-allocated space for the
984263bc 210.Va cam_device
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211structure.
212If the
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213.Ar device
214argument is
215.Va NULL ,
216.Fn cam_open_spec_device
217will allocate space for the
218.Va cam_device
219structure using
220.Xr malloc 3 .
221.Pp
222.Fn cam_open_btl
223is similar to
224.Fn cam_open_spec_device ,
225except that it takes a
226.Tn SCSI
227bus, target and logical unit instead of a device name and unit number as
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228arguments.
229The
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230.Va path_id
231argument is the CAM equivalent of a
232.Tn SCSI
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233bus number.
234It represents the logical bus number in the system.
235The
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236.Ar flags
237should be flags suitable for passing to
238.Xr open 2 .
239As with
240.Fn cam_open_spec_device ,
241the
242.Fa device
243argument is optional.
244.Pp
245.Fn cam_open_pass
246takes as an argument the
247.Fa path
248of a
249.Xr pass 4
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250device to open.
251No translation or lookup is performed, so the path passed
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252in must be that of a CAM
253.Xr pass 4
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254device.
255The
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256.Fa flags
257should be flags suitable for passing to
258.Xr open 2 .
259The
260.Fa device
261argument, as with
262.Fn cam_open_spec_device
263and
264.Fn cam_open_btl ,
265should be NULL if the user wants the CAM library to allocate space for the
266.Va cam_device
267structure.
268.Fn cam_close_device
269frees the
270.Va cam_device
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271structure allocated by one of the above
272.Fn open
273calls, and closes the file
274descriptor to the passthrough device.
275This routine should not be called if the user allocated space for the
984263bc 276.Va cam_device
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277structure.
278Instead, the user should call
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279.Fn cam_close_spec_device .
280.Pp
281.Fn cam_close_spec_device
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282merely closes the file descriptor opened in one of the
283.Fn open
284routines described above.
285This function should be called when the
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286.Va cam_device
287structure was allocated by the caller, rather than the CAM library.
288.Pp
289.Fn cam_getccb
290allocates a CCB
291using
292.Xr malloc 3
293and sets fields in the CCB header using values from the
294.Va cam_device
295structure.
296.Pp
297.Fn cam_send_ccb
298sends the given
299.Va ccb
300to the
301.Fa device
302described in the
303.Va cam_device
304structure.
305.Pp
306.Fn cam_freeccb
307frees CCBs allocated by
308.Fn cam_getccb .
309.Pp
310.Fn cam_path_string
311takes as arguments a
312.Va cam_device
313structure, and a string with length
314.Fa len .
315It creates a colon-terminated printing prefix string similar to the ones
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316used by the kernel, e.g.\&
317.Dq (cd0:ahc1:0:4:0): .
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318.Fn cam_path_string
319will place at most
320.Fa len Ns \-1
321characters into
322.Ar str .
323The
324.Ar len Ns 'th
325character will be the terminating
326.Ql \e0 .
327.Pp
328.Fn cam_device_dup
329operates in a fashion similar to
330.Xr strdup 3 .
331It allocates space for a
332.Va cam_device
333structure and copies the contents of the passed-in
334.Fa device
335structure to the newly allocated structure.
336.Pp
337.Fn cam_device_copy
338copies the
339.Fa src
340structure to
341.Fa dst .
342.Pp
343.Fn cam_get_device
344takes a
345.Fa path
346argument containing a string with a device name followed by a unit number.
347It then breaks the string down into a device name and unit number, and
348passes them back in
349.Fa dev_name
350and
351.Fa unit ,
352respectively.
353.Fn cam_get_device
354can handle strings of the following forms, at least:
355.Pp
356.Bl -tag -width 1234 -compact
357.It /dev/foo0a
358.It /dev/foo1s2c
359.It foo0
360.It foo0a
361.It nfoo0
362.El
363.Pp
364.Fn cam_get_device
365is provided as a convenience function for applications that need to provide
366functionality similar to
367.Fn cam_open_device .
368Programmers are encouraged to use more deterministic methods of obtaining
369device names and unit numbers if possible.
370.Sh RETURN VALUES
371.Fn cam_open_device ,
372.Fn cam_open_spec_device ,
373.Fn cam_open_btl ,
374and
375.Fn cam_open_pass
376return a pointer to a
377.Va cam_device
378structure, or NULL if there was an error.
379.Pp
380.Fn cam_getccb
381returns an allocated and partially initialized CCB, or NULL if allocation
382of the CCB failed.
383.Pp
384.Fn cam_send_ccb
3f625015 385returns a value of -1 if an error occurred, and
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386.Va errno
387is set to indicate the error.
388.Pp
389.Fn cam_path_string
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390returns a filled printing prefix string as a convenience.
391This is the same
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392.Fa str
393that is passed into
394.Fn cam_path_string .
395.Pp
396.Fn cam_device_dup
397returns a copy of the
398.Va device
399passed in, or NULL if an error occurred.
400.Pp
401.Fn cam_get_device
402returns 0 for success, and -1 to indicate failure.
403.Pp
404If an error is returned from one of the base CAM library functions
405described here, the reason for the error is generally printed in the global
406string
407.Va cam_errbuf
408which is
409.Dv CAM_ERRBUF_SIZE
410characters long.
411.Sh SEE ALSO
412.Xr cam_cdbparse 3 ,
413.Xr pass 4 ,
414.Xr camcontrol 8
415.Sh HISTORY
416The CAM library first appeared in
417.Fx 3.0 .
418.Sh AUTHORS
98b3d9ad 419.An Kenneth Merry Aq Mt ken@FreeBSD.org
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420.Sh BUGS
421.Fn cam_open_device
422doesn't check to see if the
423.Fa path
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424passed in is a symlink to something.
425It also doesn't check to see if the
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426.Fa path
427passed in is an actual
428.Xr pass 4
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429device.
430The former would be rather easy to implement, but the latter would
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431require a definitive way to identify a device node as a
432.Xr pass 4
433device.
434.Pp
435Some of the functions are possibly mis-named or poorly named.