devid_get(3DEVID) Device ID Library Functions devid_get(3DEVID)NAME
devid_get, devid_compare, devid_deviceid_to_nmlist, devid_free,
devid_free_nmlist, devid_get_minor_name, devid_sizeof,
devid_str_decode, devid_str_free, devid_str_encode, devid_valid -
device ID interfaces for user applications
SYNOPSIS
cc [ flag... ] file... -ldevid [ library... ]
#include <devid.h>
int devid_get(int fd, ddi_devid_t *retdevid);
void devid_free(ddi_devid_t devid);
int devid_get_minor_name(int fd, char **retminor_name);
int devid_deviceid_to_nmlist(char *search_path, ddi_devid_t devid, char
*minor_name, devid_nmlist_t **retlist);
void devid_free_nmlist(devid_nmlist_t *list);
int devid_compare(ddi_devid_t devid1, ddi_devid_t devid2);
size_t devid_sizeof(ddi_devid_t devid);
int devid_valid(ddi_devid_t devid);
char *devid_str_encode(ddi_devid_t devid, char *minor_name);
int devid_str_decode(char *devidstr, ddi_devid_t *retdevid, char **ret‐
minor_name);
void devid_str_free(char *str);
DESCRIPTION
These functions provide unique identifiers (device IDs) for devices.
Applications and device drivers use these functions to identify and
locate devices, independent of the device's physical connection or its
logical device name or number.
The devid_get() function returns in retdevid the device ID for the
device associated with the open file descriptor fd, which refers to any
device. It returns an error if the device does not have an associated
device ID. The caller must free the memory allocated for retdevid using
the devid_free() function.
The devid_free() function frees the space that was allocated for the
returned devid by devid_get() and devid_str_decode().
The devid_get_minor_name() function returns the minor name, in retmi‐
nor_name, for the device associated with the open file descriptor fd.
This name is specific to the particular minor number, but is "instance
number" specific. The caller of this function must free the memory
allocated for the returned retminor_name string using devid_str_free().
The devid_deviceid_to_nmlist() function returns an array of
devid_nmlist structures, where each entry matches the devid and
minor_name passed in. If the minor_name specified is one of the special
values (DEVID_MINOR_NAME_ALL, DEVID_MINOR_NAME_ALL_CHR, or
DEVID_MINOR_NAME_ALL_BLK) , then all minor names associated with devid
which also meet the special minor_name filtering requirements are
returned. The devid_nmlist structure contains the device name and
device number. The last entry of the array contains a null pointer for
the devname and NODEV for the device number. This function traverses
the file tree, starting at search_path. For each device with a matching
device ID and minor name tuple, a device name and device number are
added to the retlist. If no matches are found, an error is returned.
The caller of this function must free the memory allocated for the
returned array with the devid_free_nmlist() function. This function may
take a long time to complete if called with the device ID of an unat‐
tached device.
The devid_free_nmlist() function frees the memory allocated by the
devid_deviceid_to_nmlist() function.
The devid_compare() function compares two device IDs and determines
both equality and sort order. The function returns an integer greater
than 0 if the device ID pointed to by devid1 is greater than the device
ID pointed to by devid2. It returns 0 if the device ID pointed to by
devid1 is equal to the device ID pointed to by devid2. It returns an
integer less than 0 if the device ID pointed to by devid1 is less than
the device ID pointed to by devid2. This function is the only valid
mechanism to determine the equality of two devids. This function may
indicate equality for arguments which by simple inspection appear dif‐
ferent.
The devid_sizeof() function returns the size of devid in bytes.
The devid_valid() function validates the format of a devid. It returns
1 if the format is valid, and 0 if invalid. This check may not be as
complete as the corresponding kernel function ddi_devid_valid() (see
ddi_devid_compare(9F)).
The devid_str_encode() function encodes a devid and minor_name into a
null-terminated ASCII string, returning a pointer to that string. To
avoid shell conflicts, the devid portion of the string is limited to
uppercase and lowercase letters, digits, and the plus (+), minus (-),
period (.), equals (=), underscore (_), tilde (~), and comma (,) char‐
acters. If there is an ASCII quote character in the binary form of a
devid, the string representation will be in hex_id form, not ascii_id
form. The comma (,) character is added for "id1," at the head of the
string devid. If both a devid and a minor_name are non-null, a slash
(/)is used to separate the devid from the minor_name in the encoded
string. If minor_name is null, only the devid is encoded. If the devid
is null then the special string "id0" is returned. Note that you cannot
compare the returned string against another string with strcmp(3C) to
determine devid equality. The string returned must be freed by calling
devid_str_free().
The devid_str_decode() function takes a string previously produced by
the devid_str_encode() or ddi_devid_str_encode() (see ddi_devid_com‐
pare(9F)) function and decodes the contained device ID and minor name,
allocating and returning pointers to the extracted parts via the retde‐
vid and retminor_name arguments. If the special devidstr "id0" was
specified, the returned device ID and minor name will both be null. A
non-null returned devid must be freed by the caller by the devid_free()
function. A non-null returned minor name must be freed by calling
devid_str_free().
The devid_str_free() function frees the character string returned by
devid_str_encode() and the retminor_name argument returned by
devid_str_decode().
RETURN VALUES
Upon successful completion, the devid_get(), devid_get_minor_name(),
devid_str_decode(), and devid_deviceid_to_nmlist() functions return 0.
Otherwise, they return −1.
The devid_compare() function returns the following values:
−1 The device ID pointed to by devid1 is less than the device ID
pointed to by devid2.
0 The device ID pointed to by devid1 is equal to the device ID
pointed to by devid2.
1 The device ID pointed to by devid1 is greater than the device
ID pointed to by devid2.
The devid_sizeof() function returns the size of devid in bytes. If
devid is null, the number of bytes that must be allocated and initial‐
ized to determine the size of a complete device ID is returned.
The devid_valid() function returns 1 if the devid is valid and 0 if the
devid is invalid.
The devid_str_encode() function returns NULL to indicate failure. Fail‐
ure may be caused by attempting to encode an invalid string. If the
return value is non-null, the caller must free the returned string by
using the devid_str_free() function.
EXAMPLES
Example 1: Using devid_get(), devid_get_minor_name(), and
devid_str_encode()
The following example shows the proper use of devid_get(),
devid_get_minor_name(), and devid_str_encode() to free the space allo‐
cated for devid, minor_name and encoded devid.
int fd;
ddi_devid_t devid;
char *minor_name, *devidstr;
if ((fd = open("/dev/dsk/c0t3d0s0", O_RDONLY|O_NDELAY)) < 0) {
...
}
if (devid_get(fd, &devid) != 0) {
...
}
if (devid_get_minor_name(fd, &minor_name) != 0) {
...
}
if ((devidstr = devid_str_encode(devid, minor_name)) == 0) {
...
}
printf("devid %s\n", devidstr);
devid_str_free(devidstr);
devid_free(devid);
devid_str_free(minor_name);
Example 2: Using devid_deviceid_to_nmlist() and devid_free_nmlist()
The following example shows the proper use of devid_devi‐
ceid_to_nmlist() and devid_free_nmlist():
devid_nmlist_t *list = NULL;
int err;
if (devid_deviceid_to_nmlist("/dev/rdsk", devid,
minor_name, &list))
return (-1);
/* loop through list and process device names and numbers */
devid_free_nmlist(list);
ATTRIBUTES
See attributes(5) for description of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT−Safe │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Stable │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOfree(3C), libdevid(3LIB), attributes(5), ddi_devid_compare(9F)SunOS 5.10 30 Nov 2001 devid_get(3DEVID)
