STREAMS

This section describes dcmds and walkers that are useful for kernel developers as well as developers of third-party STREAMS modules and drivers.

STREAMS Dcmds

address ::mblk2dblk

Given the address of an mblk_t, print the address of the corresponding dblk_t.

[address] ::mblk_verify

Verify the integrity of one or more message blocks. If an explicit message block address is specified, the integrity of this message block is checked. If no address is specified, the integrity of all active message blocks are checked. This dcmd produces output for any invalid message block state that is detected.

address ::queue [-v] [-f flag] [-F flag] [-s syncq]

Filter and display the specified queue_t data structure. With no options, various properties of the queue_t are shown. If the -v option is present, the queue flags are decoded in greater detail. If the -f, -F, or -m options are present, the queue is displayed only if it matches the criteria defined by the arguments to these options; in this way, the dcmd can be used as a filter for input from a pipeline. The -f option indicates that the specified flag (one of the Q flag names from <sys/stream.h>) must be present in the queue flags. The -F option indicates that the specified flag must be absent from the queue flags. The -m option indicates that the module name associated with the queue must match the specified modname. The -s option indicates that the syncq_t associated with the queue must match the specified syncq_t address.

address ::q2syncq

Given the address of a queue_t, print the address of the corresponding syncq_t data structure.

address ::q2otherq

Given the address of a queue_t, print the address of the peer read or write queue structure.

address ::q2rdq

Given the address of a queue_t, print the address of the corresponding read queue.

address ::q2wrq

Given the address of a queue_t, print the address of the corresponding write queue.

[ address ] ::stream

Display a visual picture of a kernel STREAM data structure, given the address of the stdata_t structure representing the STREAM head. The read and write queue pointers, byte count, and flags for each module are shown, and in some cases additional information for the specific queue is shown in the margin.

address ::syncq [-v] [-f flag] [-F flag] [-t type] [-T type]

Filter and display the specified syncq_t data structure. With no options, various properties of the syncq_t are shown. If the -v option is present, the syncq flags are decoded in greater detail. If the -f, -F, -t, or -T options are present, the syncq is displayed only if it matches the criteria defined by the arguments to these options; in this way, the dcmd can be used as a filter for input from a pipeline. The -f option indicates that the specified flag (one of the SQ_ flag names from <sys/strsubr.h>) must be present in the syncq flags. The -F option indicates that the specified flag must be absent from the syncq flags. The -t option indicates that the specified type (one of the SQ_CI or SQ_CO type names from <sys/strsubr.h>) must be present in the syncq type bits. The -T option indicates that the specified type must be absent from the syncq type bits.

address ::syncq2q

Given the address of a syncq_t, print the address of the corresponding queue_t data structure.

STREAMS Walkers

b_cont

Given the address of an mblk_t, iterate over the set of associated message structures by following the b_cont pointer. The b_cont pointer is used to link a given message block to the next associated message block that is the continuation of the same message. The message block is described in more detail in msgb(9S)

b_next

Given the address of an mblk_t, iterate over the set of associated message structures by following the b_next pointer. The b_next pointer is used to link a given message block to the next associated message block on a given queue. The message block is described in more detail in msgb(9S).

qlink

Given the address of a queue_t structure, walk the list of related queues using the q_link pointer. This structure is defined in <sys/stream.h>.

qnext

Given the address of a queue_t structure, walk the list of related queues using the q_next pointer. This structure is defined in <sys/stream.h>.

readq

Given the address of an stdata_t structure, walk the list of read-side queue structures.

writeq

Given the address of an stdata_t structure, walk the list of write-side queue structures.