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

flags

ops

data

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.