task_pgrp

函数名称：Without tasklist or RCU lock it is not safe to dereference* the result of task_pgrp/task_session even if task == current,* we can race with another thread doing sys_setsid/sys_setpgid.

函数原型：static inline struct pid *task_pgrp(struct task_struct *task)

返回类型：struct pid

参数：

类型	参数	名称
struct task_struct *	task

**调用者**
名称	描述
copy_process	创建进程
will_become_orphaned_pgrp	Determine if a process group is "orphaned", according to the POSIX* definition in 2
is_current_pgrp_orphaned
kill_orphaned_pgrp	Check to see if any process groups have become orphaned as* a result of our exiting, and if they have any stopped jobs,* send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
kill_something_info	kill_something_info() interprets pid in interesting ways just like kill(2).* POSIX specifies that kill(-1,sig) is unspecified, but what we have* is probably wrong. Should make it like BSD or SYSV.
SYSCALL_DEFINE3
SYSCALL_DEFINE2	Ugh. To avoid negative return values, "getpriority()" will* not return the normal nice-value, but a negated value that* has been offset by 20 (ie it returns 40..1 instead of -20..19)* to stay compatible.
SYSCALL_DEFINE2	This needs some heavy checking
do_getpgid
set_special_pids
SYSCALL_DEFINE3
SYSCALL_DEFINE2

函数逻辑报告