UTRACE_ATTACH_TASK(9)						  utrace core API					     UTRACE_ATTACH_TASK(9)

NAME

       utrace_attach_task - attach new engine, or look up an attached engine

SYNOPSIS

       struct utrace_engine * utrace_attach_task(struct task_struct * target, int flags, const struct utrace_engine_ops * ops, void * data);

ARGUMENTS

       target
	   thread to attach to

       flags
	   flag bits combined with OR, see below

       ops
	   callback table for new engine

       data
	   engine private data pointer

DESCRIPTION

       The caller must ensure that the target thread does not get freed, i.e. hold a ref or be its parent. It is always safe to call this on
       current, or on the child pointer in a report_clone callback. For most other cases, it's easier to use utrace_attach_pid instead.

UTRACE_ATTACH_CREATE
       Create a new engine. If UTRACE_ATTACH_CREATE is not specified, you only look up an existing engine already attached to the thread.

UTRACE_ATTACH_EXCLUSIVE
       Attempting to attach a second (matching) engine fails with -EEXIST.

UTRACE_ATTACH_MATCH_OPS
       Only consider engines matching ops.

UTRACE_ATTACH_MATCH_DATA
       Only consider engines matching data.

       Calls with neither UTRACE_ATTACH_MATCH_OPS nor UTRACE_ATTACH_MATCH_DATA match the first among any engines attached to target. That means
       that UTRACE_ATTACH_EXCLUSIVE in such a call fails with -EEXIST if there are any engines on target at all.

Kernel Hackers Manual 2.6.					     July 2010						     UTRACE_ATTACH_TASK(9)