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<a name='L125'> <b>continue</b>;
<a name='L126'> <b>if</b> (task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>]->pid != pid)
<a name='L127'> <b>continue</b>;
<a name='L128'> task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>]->signal |= (1 << (<a href='../S/39.html#L30' title='Defined at 30 in include/signal.h.'>SIGCHLD</a> - 1));
<a name='L129'> <b>return</b>;
<a name='L130'> <font color='red'>}</font>
<a name='L131'><i><font color='green'>/* if we don't find any fathers, we just release ourselves */</font></i>
<a name='L132'><i><font color='green'>/* This is not really OK. Must change it to make father 1 */</font></i>
<a name='L133'> <a href='../S/73.html#L30' title='Defined at 30 in kernel/printk.c.'>printk</a> ("BAD BAD - no father found\n\r");
<a name='L134'> <a href='../S/67.html#L22' title='Defined at 22 in kernel/exit.c.'>release</a> (current); <i><font color='green'>// 如果没有找到父进程，则自己释放。</font></i>
<a name='L135'><font color='red'>}</font>
<a name='L136'>
<a name='L137'><i><font color='green'>//// 程序退出处理程序。在系统调用的中断处理程序中被调用。</font></i>
<a name='L138'><b>int</b>
<a name='L139'><a href='../R/437.html' title='Multiple refered from 8 places.'>do_exit</a> (<b>long</b> code) <i><font color='green'>// code 是错误码。</font></i>
<a name='L140'><font color='red'>{</font>
<a name='L141'> <b>int</b> <a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>;
<a name='L142'>
<a name='L143'><i><font color='green'>// 释放当前进程代码段和数据段所占的内存页(free_page_tables()在mm/memory.c,105 行)。</font></i>
<a name='L144'> <a href='../S/94.html#L158' title='Defined at 158 in mm/memory.c.'>free_page_tables</a> (<a href='../S/36.html#L343' title='Defined at 343 in include/linux/sched.h.'>get_base</a> (current->ldt[1]), <a href='../S/36.html#L346' title='Defined at 346 in include/linux/sched.h.'>get_limit</a> (0x0f));
<a name='L145'> <a href='../S/94.html#L158' title='Defined at 158 in mm/memory.c.'>free_page_tables</a> (<a href='../S/36.html#L343' title='Defined at 343 in include/linux/sched.h.'>get_base</a> (current->ldt[2]), <a href='../S/36.html#L346' title='Defined at 346 in include/linux/sched.h.'>get_limit</a> (0x17));
<a name='L146'><i><font color='green'>// 如果当前进程有子进程，就将子进程的father 置为1(其父进程改为进程1)。如果该子进程已经</font></i>
<a name='L147'><i><font color='green'>// 处于僵死(ZOMBIE)状态，则向进程1 发送子进程终止信号SIGCHLD。</font></i>
<a name='L148'> <b>for</b> (<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a> = 0; <a href='../D/839.html' title='Multiple defined in 4 places.'>i</a> < <a href='../S/36.html#L4' title='Defined at 4 in include/linux/sched.h.'>NR_TASKS</a>; <a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>++)
<a name='L149'> <b>if</b> (task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>] && task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>]->father == current->pid)
<a name='L150'> <font color='red'>{</font>
<a name='L151'> task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>]->father = 1;
<a name='L152'> <b>if</b> (task[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>]->state == <a href='../S/36.html#L23' title='Defined at 23 in include/linux/sched.h.'>TASK_ZOMBIE</a>)
<a name='L153'><i><font color='green'>/* assumption task[1] is always init */</font></i>
<a name='L154'> (<b>void</b>) <a href='../S/67.html#L41' title='Defined at 41 in kernel/exit.c.'>send_sig</a> (<a href='../S/39.html#L30' title='Defined at 30 in include/signal.h.'>SIGCHLD</a>, task[1], 1);
<a name='L155'> <font color='red'>}</font>
<a name='L156'><i><font color='green'>// 关闭当前进程打开着的所有文件。</font></i>
<a name='L157'> <b>for</b> (<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a> = 0; <a href='../D/839.html' title='Multiple defined in 4 places.'>i</a> < <a href='../S/31.html#L59' title='Defined at 59 in include/linux/fs.h.'>NR_OPEN</a>; <a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>++)
<a name='L158'> <b>if</b> (current->filp[<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>])
<a name='L159'> <a href='../S/15.html#L299' title='Defined at 299 in fs/open.c.'>sys_close</a> (<a href='../D/839.html' title='Multiple defined in 4 places.'>i</a>);
<a name='L160'><i><font color='green'>// 对当前进程工作目录pwd、根目录root 以及运行程序的i 节点进行同步操作，并分别置空。</font></i>
<a name='L161'> <a href='../S/12.html#L221' title='Defined at 221 in fs/inode.c.'>iput</a> (current->pwd);
<a name='L162'> current->pwd = <a href='../D/261.html' title='Multiple defined in 12 places.'>NULL</a>;
<a name='L163'> <a href='../S/12.html#L221' title='Defined at 221 in fs/inode.c.'>iput</a> (current->root);
<a name='L164'> current->root = <a href='../D/261.html' title='Multiple defined in 12 places.'>NULL</a>;
<a name='L165'> <a href='../S/12.html#L221' title='Defined at 221 in fs/inode.c.'>iput</a> (current->executable);
<a name='L166'> current->executable = <a href='../D/261.html' title='Multiple defined in 12 places.'>NULL</a>;
<a name='L167'><i><font color='green'>// 如果当前进程是领头(leader)进程并且其有控制的终端，则释放该终端。</font></i>
<a name='L168'> <b>if</b> (current->leader && current-><a href='../S/7.html#L44' title='Defined at 44 in fs/char_dev.c.'>tty</a> >= 0)
<a name='L169'> tty_table[current-><a href='../S/7.html#L44' title='Defined at 44 in fs/char_dev.c.'>tty</a>].pgrp = 0;
<a name='L170'><i><font color='green'>// 如果当前进程上次使用过协处理器，则将last_task_used_math 置空。</font></i>
<a name='L171'> <b>if</b> (last_task_used_math == current)
<a name='L172'> last_task_used_math = <a href='../D/261.html' title='Multiple defined in 12 places.'>NULL</a>;
<a name='L173'><i><font color='green'>// 如果当前进程是leader 进程，则终止所有相关进程。</font></i>
<a name='L174'> <b>if</b> (current->leader)
<a name='L175'> <a href='../S/67.html#L57' title='Defined at 57 in kernel/exit.c.'>kill_session</a> ();
<a name='L176'><i><font color='green'>// 把当前进程置为僵死状态，并设置退出码。</font></i>
<a name='L177'> current->state = <a href='../S/36.html#L23' title='Defined at 23 in include/linux/sched.h.'>TASK_ZOMBIE</a>;
<a name='L178'> current->exit_code = code;
<a name='L179'><i><font color='green'>// 通知父进程，也即向父进程发送信号SIGCHLD -- 子进程将停止或终止。</font></i>
<a name='L180'> <a href='../S/67.html#L117' title='Defined at 117 in kernel/exit.c.'>tell_father</a> (current->father);
<a name='L181'> <a href='../S/74.html#L146' title='Defined at 146 in kernel/sched.c.'>schedule</a> (); <i><font color='green'>// 重新调度进程的运行。</font></i>
<a name='L182'> <b>return</b> (-1); <i><font color='green'>/* just to suppress warnings */</font></i>
<a name='L183'><font color='red'>}</font>
<a name='L184'>
<a name='L185'><i><font color='green'>//// 系统调用exit()。终止进程。</font></i>
<a name='L186'><b>int</b>
<a name='L187'><a href='../R/641.html' title='Multiple refered from 3 places.'>sys_exit</a> (<b>int</b> error_code)
<a name='L188'><font color='red'>{</font>
<a name='L189'> <b>return</b> <a href='../S/67.html#L139' title='Defined at 139 in kernel/exit.c.'>do_exit</a> ((error_code & 0xff) << 8);
<a name='L190'><font color='red'>}</font>
<a name='L191'>
<a name='L192'><i><font color='green'>//// 系统调用waitpid()。挂起当前进程，直到pid 指定的子进程退出（终止）或者收到要求终止</font></i>
<a name='L193'><i><font color='green'>// 该进程的信号，或者是需要调用一个信号句柄（信号处理程序）。如果pid 所指的子进程早已</font></i>
<a name='L194'><i><font color='green'>// 退出（已成所谓的僵死进程），则本调用将立刻返回。子进程使用的所有资源将释放。</font></i>
<a name='L195'><i><font color='green'>// 如果pid > 0, 表示等待进程号等于pid 的子进程。</font></i>
<a name='L196'><i><font color='green'>// 如果pid = 0, 表示等待进程组号等于当前进程的任何子进程。</font></i>
<a name='L197'><i><font color='green'>// 如果pid < -1, 表示等待进程组号等于pid 绝对值的任何子进程。</font></i>
<a name='L198'><i><font color='green'>// [ 如果pid = -1, 表示等待任何子进程。]</font></i>
<a name='L199'><i><font color='green'>// 若options = WUNTRACED，表示如果子进程是停止的，也马上返回。</font></i>
<a name='L200'><i><font color='green'>// 若options = WNOHANG，表示如果没有子进程退出或终止就马上返回。</font></i>
<a name='L201'><i><font color='green'>// 如果stat_addr 不为空，则就将状态信息保存到那里。</font></i>
<a name='L202'><b>int</b>
<a name='L203'><a href='../R/696.html' title='Multiple refered from 2 places.'>sys_waitpid</a> (<a href='../S/45.html#L23' title='Defined at 23 in include/sys/types.h.'>pid_t</a> pid, <b>unsigned</b> <b>long</b> *stat_addr, <b>int</b> options)
<a name='L204'><font color='red'>{</font>
<a name='L205'> <b>int</b> flag, code;
<a name='L206'> <b>struct</b> task_struct **p;
<a name='L207'>
<a name='L208'> <a href='../S/68.html#L34' title='Defined at 34 in kernel/fork.c.'>verify_area</a> (stat_addr, 4);
<a name='L209'>repeat:
<a name='L210'> flag = 0;
<a name='L211'> <b>for</b> (p = &<a href='../S/36.html#L8' title='Defined at 8 in include/linux/sched.h.'>LAST_TASK</a>; p > &<a href='../S/36.html#L7' title='Defined at 7 in include/linux/sched.h.'>FIRST_TASK</a>; --p)
<a name='L212'> <font color='red'>{</font> <i><font color='green'>// 从任务数组末端开始扫描所有任务。</font></i>
<a name='L213'> <b>if</b> (!*p || *p == current) <i><font color='green'>// 跳过空项和本进程项。</font></i>
<a name='L214'> <b>continue</b>;
<a name='L215'> <b>if</b> ((*p)->father != current->pid) <i><font color='green'>// 如果不是当前进程的子进程则跳过。</font></i>
<a name='L216'> <b>continue</b>;
<a name='L217'> <b>if</b> (pid > 0)
<a name='L218'> <font color='red'>{</font> <i><font color='green'>// 如果指定的pid>0，但扫描的进程pid</font></i>
<a name='L219'> <b>if</b> ((*p)->pid != pid) <i><font color='green'>// 与之不等，则跳过。</font></i>
<a name='L220'> <b>continue</b>;
<a name='L221'> <font color='red'>}</font>
<a name='L222'> <b>else</b> <b>if</b> (!pid)
<a name='L223'> <font color='red'>{</font> <i><font color='green'>// 如果指定的pid=0，但扫描的进程组号</font></i>
<a name='L224'> <b>if</b> ((*p)->pgrp != current->pgrp) <i><font color='green'>// 与当前进程的组号不等，则跳过。</font></i>
<a name='L225'> <b>continue</b>;
<a name='L226'> <font color='red'>}</font>
<a name='L227'> <b>else</b> <b>if</b> (pid != -1)
<a name='L228'> <font color='red'>{</font> <i><font color='green'>// 如果指定的pid<-1，但扫描的进程组</font></i>
<a name='L229'> 号if ((*p)->pgrp != -pid) <i><font color='green'>// 与其绝对值不等，则跳过。</font></i>
<a name='L230'> <b>continue</b>;
<a name='L231'> <font color='red'>}</font>
<a name='L232'> <b>switch</b> ((*p)->state)
<a name='L233'> <font color='red'>{</font>
<a name='L234'> <b>case</b> <a href='../S/36.html#L24' title='Defined at 24 in include/linux/sched.h.'>TASK_STOPPED</a>:
<a name='L235'> <b>if</b> (!(options & <a href='../S/47.html#L12' title='Defined at 12 in include/sys/wait.h.'>WUNTRACED</a>))
<a name='L236'> <b>continue</b>;
<a name='L237'> <a href='../S/24.html#L62' title='Defined at 62 in include/asm/segment.h.'>put_fs_long</a> (0x7f, stat_addr); <i><font color='green'>// 置状态信息为0x7f。</font></i>
<a name='L238'> <b>return</b> (*p)->pid; <i><font color='green'>// 退出，返回子进程的进程号。</font></i>
<a name='L239'> <b>case</b> <a href='../S/36.html#L23' title='Defined at 23 in include/linux/sched.h.'>TASK_ZOMBIE</a>:
<a name='L240'> current->cutime += (*p)->utime; <i><font color='green'>// 更新当前进程的子进程用户</font></i>
<a name='L241'> current->cstime += (*p)->stime; <i><font color='green'>// 态和核心态运行时间。</font></i>
<a name='L242'> flag = (*p)->pid;
<a name='L243'> code = (*p)->exit_code; <i><font color='green'>// 取子进程的退出码。</font></i>
<a name='L244'> <a href='../S/67.html#L22' title='Defined at 22 in kernel/exit.c.'>release</a> (*p); <i><font color='green'>// 释放该子进程。</font></i>
<a name='L245'> <a href='../S/24.html#L62' title='Defined at 62 in include/asm/segment.h.'>put_fs_long</a> (code, stat_addr); <i><font color='green'>// 置状态信息为退出码值。</font></i>
<a name='L246'> <b>return</b> flag; <i><font color='green'>// 退出，返回子进程的pid.</font></i>
<a name='L247'> <b>default</b>:
<a name='L248'> flag = 1; <i><font color='green'>// 如果子进程不在停止或僵死状态，则flag=1。</font></i>
<a name='L249'> <b>continue</b>;
<a name='L250'> <font color='red'>}</font>
<a name='L251'> <font color='red'>}</font>
<a name='L252'> <b>if</b> (flag)
<a name='L253'> <font color='red'>{</font> <i><font color='green'>// 如果子进程没有处于退出或僵死状态，</font></i>
<a name='L254'> <b>if</b> (options & <a href='../S/47.html#L11' title='Defined at 11 in include/sys/wait.h.'>WNOHANG</a>) <i><font color='green'>// 并且options = WNOHANG，则立刻返回。</font></i>
<a name='L255'> <b>return</b> 0;
<a name='L256'> current->state = <a href='../S/36.html#L21' title='Defined at 21 in include/linux/sched.h.'>TASK_INTERRUPTIBLE</a>; <i><font color='green'>// 置当前进程为可中断等待状态。</font></i>
<a name='L257'> <a href='../S/74.html#L146' title='Defined at 146 in kernel/sched.c.'>schedule</a> (); <i><font color='green'>// 重新调度。</font></i>
<a name='L258'> <b>if</b> (!(current->signal &= ~(1 << (<a href='../S/39.html#L30' title='Defined at 30 in include/signal.h.'>SIGCHLD</a> - 1)))) <i><font color='green'>// 又开始执行本进程时，</font></i>
<a name='L259'> <b>goto</b> repeat; <i><font color='green'>// 如果进程没有收到除SIGCHLD 的信号，则还是重复处理。</font></i>
<a name='L260'> <b>else</b>
<a name='L261'> <b>return</b> -<a href='../S/28.html#L33' title='Defined at 33 in include/errno.h.'>EINTR</a>; <i><font color='green'>// 退出，返回出错码。</font></i>
<a name='L262'> <font color='red'>}</font>
<a name='L263'> <b>return</b> -<a href='../S/28.html#L39' title='Defined at 39 in include/errno.h.'>ECHILD</a>;
<a name='L264'><font color='red'>}</font>
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