{"id":911,"date":"2019-11-12T16:09:20","date_gmt":"2019-11-12T08:09:20","guid":{"rendered":"http:\/\/149.129.74.185\/?p=911"},"modified":"2019-11-12T16:57:39","modified_gmt":"2019-11-12T08:57:39","slug":"%e6%93%8d%e4%bd%9c%e7%b3%bb%e7%bb%9fweek-9-note","status":"publish","type":"post","link":"http:\/\/www.magicmipamipa.com\/?p=911","title":{"rendered":"[\u64cd\u4f5c\u7cfb\u7edf]Week 9 Note"},"content":{"rendered":"

\u5b9e\u9a8c1\u30012\u8981\u4f20\u5230PAT\u4e0a\/\u6ce8\u610f\u7f16\u7801\u7684\u683c\u5f0f\u95ee\u9898<\/em><\/span><\/p>\n

Linux \u8fdb\u7a0b\u7ba1\u7406<\/span><\/strong><\/span><\/h2>\n

 <\/p>\n

Linux\u8fdb\u7a0b\u6982\u5ff5<\/span><\/strong><\/span><\/h3>\n
\n

\u00b7Linux\u8fdb\u7a0b\u4e0e\u4f20\u7edfUNIX\u8fdb\u7a0b\u7684\u6982\u5ff5\u6ca1\u6709\u591a\u5927\u533a\u522b\u3002 \u6ca1\u6709\u771f\u6b63\u610f\u4e49\u4e0a\u7684\u7ebf\u7a0b\u6982\u5ff5\u3002\u4f46Linux\u901a\u8fc7clone()\u7cfb\u7edf\u8c03\u7528\u652f\u6301\u8f7b\u91cf\u7ea7(Lightweight process)\u8fdb\u7a0b(\u7ebf\u7a0b)\u3002\u00b7<\/span>Linux\u8fd8\u652f\u6301\u5185\u6838\u7ebf\u7a0b\uff0c\u5185\u6838\u7ebf\u7a0b\u6c38\u8fdc\u5728\u5185\u6838\u6001\u8fd0\u884c\uff0c\u6ca1\u6709\u7528\u6237\u7a7a\u95f4\u3002<\/span><\/span><\/h3>\n

ps\u6307\u4ee4<\/span><\/strong><\/span><\/h4>\n

Linux\u4e2d\u8fd0\u884cps\u547d\u4ee4\uff0c\u4f60\u80fd\u5f97\u5230\u5f53\u524d\u7cfb\u7edf\u4e2d\u8fdb\u7a0b\u7684\u5217\u8868\uff0c\u6bd4\u5982\uff1a<\/span><\/p>\n

$ ps x<\/span>
\nPID TTY STAT TIME COMMAND<\/span>
\n1668 tty1 Ss 0:00 -bash<\/span>
\n3209 tty1 R 0:02 xterm<\/span>
\n3211 pts\/0 Ss 0:00 bash<\/span>
\n4400 pts\/0 R+ 0:00 ps x<\/span><\/p>\n

Linx\u8fdb\u7a0b\u72b6\u6001<\/span><\/strong><\/span><\/h3>\n
\n

task_struct<\/strong><\/span><\/p>\n

\uff5e\uff5eLinux\u7684PCB\u63a7\u5236\u5757<\/span><\/p>\n

\u7ed3\u6784\u4e2d\u5b9a\u4e49\uff1a<\/span><\/p>\n

volatile long state;<\/span><\/p>\n

int exit_state;<\/span><\/p>\n

    \n
  • \u7528\u4e8e\u8868\u793a\u8fdb\u7a0b\u7684\u72b6\u6001<\/span><\/li>\n
  • \u524d\u8005\u8868\u793a\u7528\u6765\u8868\u5f81\u8fdb\u7a0b\u7684\u53ef\u8fd0\u884c\u6027\uff0c<\/span><\/li>\n
  • \u540e\u8005\u8868\u5f81\u8fdb\u7a0b\u9000\u51fa\u65f6\u5019\u7684\u72b6\u6001\u3002\u00a0<\/span><\/li>\n<\/ul>\n

    do_fork()<\/span><\/strong><\/h3>\n
    \n

    do_fork()\u7684\u6267\u884c\u8fc7\u7a0b(\u6e90\u4ee3\u7801\u5728kernel\/fork.c\u6587\u4ef6\u4e2d)\uff1a <\/span><\/p>\n

    1. \u8c03\u7528alloc_task_struct()\u5206\u914d\u5b50\u8fdb\u7a0btask_struct\u7a7a\u95f4\u3002\u4e25\u683c\u5730\u8bb2\uff0c\u6b64\u65f6\u5b50\u8fdb \u7a0b\u8fd8\u672a\u751f\u6210\u3002<\/span><\/p>\n

    2. \u628a\u7236\u8fdb\u7a0btask_struct\u7684\u503c\u5168\u90e8\u8d4b\u7ed9\u5b50\u8fdb\u7a0btask_struct\u3002 <\/span><\/p>\n

    3. \u68c0\u67e5\u662f\u5426\u8d85\u8fc7\u4e86\u8d44\u6e90\u9650\u5236\uff0c\u5982\u679c\u662f\uff0c\u5219\u7ed3\u675f\u5e76\u8fd4\u56de\u51fa\u9519\u4fe1\u606f\u3002\u66f4\u6539\u4e00\u4e9b\u7edf \u8ba1\u91cf\u7684\u4fe1\u606f\u3002<\/span><\/p>\n

    4. \u4fee\u6539\u5b50\u8fdb\u7a0btask_struct\u7684\u67d0\u4e9b\u6210\u5458\u7684\u503c\u4f7f\u5176\u6b63\u786e\u53cd\u6620\u5b50\u8fdb\u7a0b\u7684\u72b6\u51b5\uff0c\u5982\u8fdb \u7a0b\u72b6\u6001\u88ab\u7f6e\u6210TASK_UNINTERRUPTIBLE\u3002 <\/span><\/p>\n

    5. \u8c03\u7528get_pid( )\u51fd\u6570\u4e3a\u5b50\u8fdb\u7a0b\u5f97\u5230\u4e00\u4e2apid\u53f7\u3002<\/span><\/p>\n

    EXE()<\/span><\/strong><\/span><\/h3>\n
    \n

    \u5728\u7cfb\u7edf\u4e2d\u521b\u5efa\u4e00\u4e2a\u8fdb\u7a0b\u7684\u76ee\u7684\u662f\u9700\u8981\u8be5\u8fdb\u7a0b\u5b8c\u6210\u4e00\u5b9a\u7684\u4efb\u52a1\uff0c\u9700\u8981\u8be5\u8fdb\u7a0b\u6267\u884c \u5b83\u7684\u7a0b\u5e8f\u4ee3\u7801\u3002 <\/span><\/p>\n

    \u5728Linux\u7cfb\u7edf\u4e2d\uff0c\u4f7f\u7a0b\u5e8f\u6267\u884c\u7684\u552f\u4e00\u65b9\u6cd5\u662f\u4f7f\u7528\u7cfb\u7edf\u8c03\u7528exec()\u3002 <\/span><\/p>\n

    \u7cfb\u7edf\u8c03\u7528exec()\u6709\u591a\u79cd\u4f7f\u7528\u5f62\u5f0f\uff0c\u79f0\u4e3aexec()\u65cf\uff0c\u5b83\u4eec\u53ea\u662f\u5728\u53c2\u6570\u4e0a\u4e0d\u540c\uff0c\u800c\u529f\u80fd\u662f\u76f8\u540c\u7684\u3002\u5982\uff1a int execl(const char * path, const char *arg0,…, const char *argn,(char*)0) <\/span><\/p>\n

      \n
    • path: \u8981\u6267\u884c\u7684\u7a0b\u5e8f\u6587\u4ef6\u7684\u5b8c\u6574\u8def\u5f84\u540d<\/span><\/li>\n
    • arg0: \u8981\u6267\u884c\u7a0b\u5e8f\u7684\u6587\u4ef6\u540d\u6216\u547d\u4ee4\u540d<\/span><\/li>\n
    • arg1,…,argn: \u6267\u884c\u7a0b\u5e8f\u6240\u9700\u7684\u53c2\u6570<\/span><\/li>\n<\/ul>\n

      exec()\u51fd\u6570\u8fd4\u503c\uff1a<\/strong><\/span><\/p>\n

        \n
      • \u8be5\u7cfb\u7edf\u8c03\u7528\u5c06\u5f15\u8d77\u53e6\u4e00\u4e2a\u7a0b\u5e8f\u7684\u6267\u884c\uff0c\u6210\u529f\u8c03\u7528\u540e\u5e76\u4e0d\u9700\u8981\u8fd4\u56de\u3002<\/span><\/li>\n
      • \u8c03\u7528\u5931\u8d25\u65f6\uff0c\u8fd4\u503c\u4e3a-1\u3002<\/span><\/li>\n<\/ul>\n

         <\/p>\n","protected":false},"excerpt":{"rendered":"

        \u5b9e\u9a8c1\u30012\u8981\u4f20\u5230PAT\u4e0a\/\u6ce8\u610f\u7f16\u7801\u7684\u683c\u5f0f\u95ee\u9898 Linux \u8fdb\u7a0b\u7ba1\u7406   Linux\u8fdb\u7a0b\u6982\u5ff5 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[16,20],"tags":[],"_links":{"self":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/911"}],"collection":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=911"}],"version-history":[{"count":6,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/911\/revisions"}],"predecessor-version":[{"id":925,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/911\/revisions\/925"}],"wp:attachment":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=911"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=911"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=911"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}