linux內(nèi)核taskstruct結(jié)構(gòu)體字段分析課件

1、linux 內(nèi)核源碼分析進程管理（一）郭海林2012.9.29linux 內(nèi)核源碼分析進程管理（一）重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（1）結(jié)構(gòu)體定義：struct list_head struct list_head *next, *prev;list_headlist_headlist_headlist_headnextprevnextprevnextprevnextprev重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（1）結(jié)構(gòu)體定義：list_head重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（2）為什么要使用這種結(jié)構(gòu)？容器機制將對象嵌入到另一個對象中怎樣通過鏈表元素找到容器對象的實例？nextprevtask_structlist_headne

2、xtprevtask_structlist_headnextprevtask_structlist_head重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（2）為什么要使用這種結(jié)構(gòu)？next重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（3）./include/linux/list.hlist_entry(p, t, m) 已知類型為t的數(shù)據(jù)結(jié)構(gòu)包含了一個list_head字段，該字段的名字是m，地址為p，返回類型為t的數(shù)據(jù)結(jié)構(gòu)地址list_entry(0 x., struct task_struct, tasks)重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（3）./include/lin重要數(shù)據(jù)結(jié)構(gòu)散列表（1）結(jié)構(gòu)體定義表頭：struct hlist_head s

3、truct hlist_node *first;節(jié)點：struct hlist_node struct hlist_node *next, *pprev;重要數(shù)據(jù)結(jié)構(gòu)散列表（1）結(jié)構(gòu)體定義重要數(shù)據(jù)結(jié)構(gòu)散列表（2）pprevnexthlist_headhlist_nodenullfirstfirstfirsthlist_nodepprevnextpprevnexthlist_nodenull重要數(shù)據(jù)結(jié)構(gòu)散列表（2）pprevnexthlist_h為什么要這么定義？進程結(jié)構(gòu)體剖析（1）struct task_struct volatile long state;/* -1 unrunnable,

4、0 runnable, 0 stopped */.long exit_state;/.進程的狀態(tài)宏定義：#define TASK_RUNNING0#define TASK_INTERRUPTIBLE1#define TASK_UNINTERRUPTIBLE2#define _TASK_STOPPED4#define _TASK_TRACED8/* in tsk-exit_state */#define EXIT_ZOMBIE16#define EXIT_DEAD32/.為什么要這么定義？進程結(jié)構(gòu)體剖析（1）struct task進程結(jié)構(gòu)體剖析（2）struct task_struct /.st

5、ruct list_head tasks; /將系統(tǒng)中所有進程通過雙向鏈表鏈接起來！/.怎樣訪問所有的進程呢？#define for_each_process(p) for (p = &init_task ; (p = next_task(p) != &init_task ; )#define next_task(p) list_entry_rcu(p)-tasks.next, struct task_struct, tasks)給出全局pid號，怎么找到相應(yīng)進程的task_struct？進程結(jié)構(gòu)體剖析（2）struct task_struct 進程結(jié)構(gòu)體剖析（3）struct task_st

6、ruct /.pid_t pid; /進程標識符（線程）pid_t tgid; /線程組的領(lǐng)頭線程IDstruct task_struct *group_leader; / threadgroup leader/. 系統(tǒng)調(diào)用 getpid() 返回什么？進程結(jié)構(gòu)體剖析（3）struct task_struct 進程結(jié)構(gòu)體剖析（4.1）struct task_struct /.struct task_struct _rcu *real_parent; /* real parent process */struct task_struct _rcu *parent; /* recipient of

7、 SIGCHLD, wait4() reports */struct list_head children; /* list of my children */struct list_head sibling; /* linkage in my parents children list */.進程之間的關(guān)系：父子關(guān)系兄弟關(guān)系進程結(jié)構(gòu)體剖析（4.1）struct task_structchildrensiblingchildrensiblingchildrensiblingchildrensiblingchildrensiblingADCBEPNNPPPNNP進程結(jié)構(gòu)體剖析（4.2）假設(shè)現(xiàn)在有

8、進程A，生成三個子進程B、C、D，B進程又生成一個子進程E。五個task_struct怎么進行鏈接？childrensiblingchildrensibling進程結(jié)構(gòu)體剖析（5.1）struct task_struct /./* PID/PID hash table linkage. */struct pid_link pidsPIDTYPE_MAX;/.enum pid_typePIDTYPE_PID,PIDTYPE_PGID,PIDTYPE_SID,PIDTYPE_MAX;/進程PID/線程組領(lǐng)頭線程PID/會話領(lǐng)頭進程ID/類型個數(shù)pids0pids1pids2進程結(jié)構(gòu)體剖析（5.1）

9、struct task_struct關(guān)鍵結(jié)構(gòu)體struct upid int nr;struct pid_namespace *ns;struct hlist_node pid_chain;struct pid_link struct hlist_node node; struct pid *pid;struct pid atomic_t count; unsigned int level; struct hlist_head tasksPIDTYPE_MAX; struct rcu_head rcu; struct upid numbers1;countlevertask0task1task

10、2nrnodepidnodepidnspid_chain 關(guān)鍵結(jié)構(gòu)體struct upid struct pid_l213pid命名空間（1）123456781092131lever 0lever 1lever 2213pid命名空間（1）123456781092131lepid命名空間（2）struct nsproxy atomic_t count;struct uts_namespace *uts_ns;struct ipc_namespace *ipc_ns;struct mnt_namespace *mnt_ns;struct pid_namespace *pid_ns;struct

11、net *net_ns;struct pid_namespace /. unsigned int level; struct pid_namespace *parent; /.;pid命名空間（2）struct nsproxy stru結(jié)構(gòu)圖見板書.結(jié)構(gòu)圖見板書.重要函數(shù)（1）根據(jù)進程的命名空間ns以及局部PID號nr，怎么找到進程的task_struct?nr,ns - upid - pid - task_structstruct pid *find_pid_ns(int nr, struct pid_namespace *ns)struct task_struct *pid_task(struct pid *pid, enum pid_type type)重要函數(shù)（1）根據(jù)進程的命名空間ns以及局部PID號nr，怎重要函數(shù)（2）給出task_struct、ID類型、命名空間，怎么取得命名空間局部的ID號？task_struct - pid - upid - nrstruct pid *task_pid(struct task_struct *task)pid_t pid_nr_ns(struct pi