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1、單擊此處編輯母版標(biāo)題樣式,單擊此處編輯母版文本樣式,第二級(jí),第三級(jí),第四級(jí),第五級(jí),*,*,*,linux 內(nèi)核源碼分析,進(jìn)程管理（一）,郭海林,2012.9.29,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_head,list_head,list_head,list_head,next,prev,next,prev,next,prev,next,prev,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(jī)制,將對(duì)象嵌入到另一個(gè)對(duì)象中,怎樣通過(guò)鏈表元素找到容器對(duì)象的實(shí)例？,next,

2、prev,task_struct,list_head,next,prev,task_struct,list_head,next,prev,task_struct,list_head,重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（3）,./include/linux/list.h,list_entry(p,t,m),已知類型為t的數(shù)據(jù)結(jié)構(gòu)包含了一個(gè)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)散列表（1）,結(jié)構(gòu)體定義,表頭：,struct hlist_head,struct hlist_no

3、de*first;,;,節(jié)點(diǎn)：,struct hlist_node,struct hlist_node*next,*pprev;,;,重要數(shù)據(jù)結(jié)構(gòu)散列表（2）,pprev,next,hlist_head,hlist_node,null,first,first,first,hlist_node,pprev,next,pprev,next,hlist_node,null,為什么要這么定義？,進(jìn)程結(jié)構(gòu)體剖析（1）,struct task_struct,volatile long state;/*-1 unrunnable,0 runnable,0 stopped*/,/.,long exit_sta

4、te;,/.,進(jìn)程的狀態(tài)宏定義：,#define,TASK_RUNNING,0,#define,TASK_INTERRUPTIBLE,1,#define,TASK_UNINTERRUPTIBLE,2,#define,_TASK_STOPPED,4,#define,_TASK_TRACED,8,/*in tsk-exit_state*/,#define,EXIT_ZOMBIE,16,#define,EXIT_DEAD,32,/.,進(jìn)程結(jié)構(gòu)體剖析（2）,struct task_struct,/.,struct list_head tasks;,/,將系統(tǒng)中所有進(jìn)程通過(guò)雙向鏈表鏈接起來(lái)！,/.,怎樣

5、訪問(wèn)所有的進(jìn)程呢？,#define,for_each_process(p),for(p=),#define,next_task(p),list_entry_rcu(p)-tasks.next,struct task_struct,tasks),給出全局pid號(hào)，怎么找到相應(yīng)進(jìn)程的task_struct？,進(jìn)程結(jié)構(gòu)體剖析（3）,struct task_struct,/.,pid_t pid;,/進(jìn)程標(biāo)識(shí)符（線程）,pid_t tgid;,/線程組的領(lǐng)頭線程ID,struct task_struct*group_leader;,/threadgroup leader,/.,系統(tǒng)調(diào)用 getpid(

6、)返回什么？,進(jìn)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 SIGCHLD,wait4()reports*/,struct list_head,children,;/*list of my children*/,struct list_head,sibling,;/*linkage in my parents children list*/,/.,進(jìn)程之間的

7、關(guān)系：,父子關(guān)系,兄弟關(guān)系,children,sibling,children,sibling,children,sibling,children,sibling,children,sibling,A,D,C,B,E,P,N,N,P,P,P,N,N,P,進(jìn)程結(jié)構(gòu)體剖析（4.2）,假設(shè)現(xiàn)在有進(jìn)程A，生成三個(gè)子進(jìn)程B、C、D，B進(jìn)程又生成一個(gè)子進(jìn)程E。,五個(gè)task_struct怎么進(jìn)行鏈接？,進(jìn)程結(jié)構(gòu)體剖析（5.1）,struct task_struct,/.,/*PID/PID hash table linkage.*/,struct pid_link pidsPIDTYPE_MAX;,/.,

8、enum pid_type,PIDTYPE_PID,PIDTYPE_PGID,PIDTYPE_SID,PIDTYPE_MAX,;,/進(jìn)程PID,/線程組領(lǐng)頭線程PID,/會(huì)話領(lǐng)頭進(jìn)程ID,/類型個(gè)數(shù),pids0,pids1,pids2,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 le

9、vel;,struct hlist_head tasksPIDTYPE_MAX;,struct rcu_head rcu;,struct upid numbers1;,;,count,lever,task0,task1,task2,nr,node,pid,node,pid,ns,pid_chain,2,1,3,pid命名空間（1）,1,2,3,4,5,6,7,8,10,9,2,1,3,1,lever 0,lever 1,lever 2,pid命名空間（2）,struct nsproxy,atomic_t count;,struct uts_namespace,*uts_ns;,struct i

10、pc_namespace,*ipc_ns;,struct mnt_namespace*mnt_ns;,struct pid_namespace,*pid_ns;,struct net,*net_ns;,;,struct pid_namespace,/.,unsigned int,level,;,struct pid_namespace*,parent,;,/.,;,結(jié)構(gòu)圖,見(jiàn)板書(shū).,重要函數(shù)（1）,根據(jù)進(jìn)程的命名空間ns以及局部PID號(hào)nr，怎么找到進(jìn)程的task_struct?,nr,ns -upid -pid -task_struct,struct pid*find_pid_ns(int

11、nr,struct pid_namespace*ns),struct task_struct*pid_task(struct pid*pid,enum pid_type type),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(hào)？,task_struct -pid -upid -nr,struct pid*task_pid(struct task_struct*task),pid_t pid_nr_ns(struct pid*pid,struct pid_namespace*ns),重要函數(shù)（3）,對(duì)于一個(gè)新建的進(jìn)程，怎么在各個(gè)命名空間內(nèi)生成唯一的PID號(hào)？,struct pid*alloc_pid(struct pid_namespace*ns),(見(jiàn)源代碼),