Партнёры:
Хостинг:
cam_open_device cam_open_spec_device cam_open_btl cam_open_pass cam_close_device cam_close_spec_device cam_getccb cam_send_ccb cam_freeccb cam_path_string cam_device_dup cam_device_copy cam_get_device - CAM user library
Lb libcam
Many of the CAM library functions use the cam_device structure:
struct cam_device {
char device_path[MAXPATHLEN+1];/*
* Pathname of the
* device given by the
* user. This may be
* null if the user
* states the device
* name and unit number
* separately.
*/
char given_dev_name[DEV_IDLEN+1];/*
* Device name given by
* the user.
*/
u_int32_t given_unit_number; /*
* Unit number given by
* the user.
*/
char device_name[DEV_IDLEN+1];/*
* Name of the device,
* e.g. 'pass'
*/
u_int32_t dev_unit_num; /* Unit number of the passthrough
* device associated with this
* particular device.
*/
char sim_name[SIM_IDLEN+1];/*
* Controller name, e.g.'ahc'
*/
u_int32_t sim_unit_number; /* Controller unit number */
u_int32_t bus_id; /* Controller bus number */
lun_id_t target_lun; /* Logical Unit Number */
target_id_t target_id; /* Target ID */
path_id_t path_id; /* System SCSI bus number */
u_int16_t pd_type; /* type of peripheral device */
struct scsi_inquiry_data inq_data; /* SCSI Inquiry data */
u_int8_t serial_num[252]; /* device serial number */
u_int8_t serial_num_len; /* length of the serial number */
u_int8_t sync_period; /* Negotiated sync period */
u_int8_t sync_offset; /* Negotiated sync offset */
u_int8_t bus_width; /* Negotiated bus width */
int fd; /* file descriptor for device */
};
cam_open_device ();
takes as arguments a string describing the device it is to open, and
flags
suitable for passing to
open(2).
The "path" passed in may actually be most any type of string that contains
a device name and unit number to be opened.
The string will be parsed by
cam_get_device ();
into a device name and unit number.
Once the device name and unit number
are determined, a lookup is performed to determine the passthrough device
that corresponds to the given device.
cam_open_device ();
is rather simple to use, but it is not really suitable for general use
because its behavior is not necessarily deterministic.
Programmers writing
new applications should make the extra effort to use one of the other open
routines documented below.
cam_open_spec_device ();
opens the
pass(4)
device that corresponds to the device name and unit number passed in.
The
flags
should be flags suitable for passing to
open(2).
The
device
argument is optional.
The user may supply pre-allocated space for the
cam_device
structure.
If the
device
argument is
NULL
cam_open_spec_device ();
will allocate space for the
cam_device
structure using
malloc(3).
cam_open_btl ();
is similar to
cam_open_spec_device (,);
except that it takes a
SCSI
bus, target and logical unit instead of a device name and unit number as
arguments.
The
path_id
argument is the CAM equivalent of a
SCSI
bus number.
It represents the logical bus number in the system.
The
flags
should be flags suitable for passing to
open(2).
As with
cam_open_spec_device (,);
the
Fa device
argument is optional.
cam_open_pass ();
takes as an argument the
Fa path
of a
pass(4)
device to open.
No translation or lookup is performed, so the path passed
in must be that of a CAM
pass(4)
device.
The
Fa flags
should be flags suitable for passing to
open(2).
The
Fa device
argument, as with
cam_open_spec_device ();
and
cam_open_btl (,);
should be NULL if the user wants the CAM library to allocate space for the
cam_device
structure.
cam_close_device ();
frees the
cam_device
structure allocated by one of the above open() calls, and closes the file
descriptor to the passthrough device.
This routine should not be called if
the user allocated space for the
cam_device
structure.
Instead, the user should call
cam_close_spec_device (.);
cam_close_spec_device ();
merely closes the file descriptor opened in one of the open() routines
described above.
This function should be called when the
cam_device
structure was allocated by the caller, rather than the CAM library.
cam_getccb ();
allocates a CCB
using
malloc(3)
and sets fields in the CCB header using values from the
cam_device
structure.
cam_send_ccb ();
sends the given
ccb
to the
Fa device
described in the
cam_device
structure.
cam_freeccb ();
frees CCBs allocated by
cam_getccb (.);
cam_path_string ();
takes as arguments a
cam_device
structure, and a string with length
Fa len .
It creates a colon-terminated printing prefix string similar to the ones
used by the kernel.
e.g.: "(cd0:ahc1:0:4:0): ".
cam_path_string ();
will place at most
Fa len Ns -1
characters into
str
The
len 'th
character will be the terminating
`\0'
cam_device_dup ();
operates in a fashion similar to
strdup(3).
It allocates space for a
cam_device
structure and copies the contents of the passed-in
Fa device
structure to the newly allocated structure.
cam_device_copy ();
copies the
Fa src
structure to
Fa dst .
cam_get_device ();
takes a
Fa path
argument containing a string with a device name followed by a unit number.
It then breaks the string down into a device name and unit number, and
passes them back in
Fa dev_name
and
Fa unit ,
respectively.
cam_get_device ();
can handle strings of the following forms, at least:
cam_get_device ();
is provided as a convenience function for applications that need to provide
functionality similar to
cam_open_device (.);
Programmers are encouraged to use more deterministic methods of obtaining
device names and unit numbers if possible.
cam_getccb ();
returns an allocated and partially initialized CCB, or NULL if allocation
of the CCB failed.
cam_send_ccb ();
returns a value of -1 if an error occured, and
errno
is set to indicate the error.
cam_path_string ();
returns a filled printing prefix string as a convenience.
This is the same
Fa str
that is passed into
cam_path_string (.);
cam_device_dup ();
returns a copy of the
device
passed in, or NULL if an error occurred.
cam_get_device ();
returns 0 for success, and -1 to indicate failure.
If an error is returned from one of the base CAM library functions described here, the reason for the error is generally printed in the global string cam_errbuf which is CAM_ERRBUF_SIZE characters long.
Some of the functions are possibly mis-named or poorly named.
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