{"id":2103,"date":"2010-12-07T09:59:04","date_gmt":"2010-12-07T01:59:04","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=2103"},"modified":"2010-12-15T15:52:04","modified_gmt":"2010-12-15T07:52:04","slug":"fork%e7%b3%bb%e7%bb%9f%e8%b0%83%e7%94%a8%e5%88%86%e6%9e%901","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/2103","title":{"rendered":"fork\u7cfb\u7edf\u8c03\u7528\u5206\u6790(1)-\u51c6\u5907\u5de5\u4f5c"},"content":{"rendered":"

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\"\"<\/a><\/p>\n

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\u8fdb\u7a0b\u63cf\u8ff0\u7b26<\/h4>\n

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\"\"<\/a><\/p>\n

\u56fe1\uff08\u56fe\u7247\u6765\u81eaULK\uff09<\/strong><\/p>\n

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\u53ef\u8fd0\u884c\u72b6\u6001\uff08TASK_RUNNING\uff09<\/strong>
\n\u5982\u679c\u8fdb\u7a0b\u6b63\u5728CPU\u4e0a\u6267\u884c\u6216\u8005\u6b63\u5728\u7b49\u5f85\u88ab\u8c03\u5ea6\u7a0b\u5e8f\u6240\u8c03\u5ea6\uff0c\u90a3\u4e48\u5b83\u7684\u72b6\u6001\u5c31\u5904\u4e8e\u53ef\u8fd0\u884c\u72b6\u6001\u3002<\/p>\n

\u6682\u505c\u72b6\u6001\uff08TASK_STOPPED\uff09<\/strong>
\n\u8fdb\u7a0b\u7684\u6267\u884c\u88ab\u6682\u5b9a\uff0c\u4e5f\u5c31\u662f\u6211\u4eec\u5e38\u8bf4\u7684\u963b\u585e\u72b6\u6001\u548c\u7b49\u5f85\u72b6\u6001\u3002\u5f53\u8fdb\u7a0b\u63a5\u6536\u5230SIGSTOP\u3001SIGSTP\u7b49\u4fe1\u53f7\u65f6\uff0c\u5c31\u8fdb\u5165\u8be5\u72b6\u6001\u3002<\/p>\n

\u8ddf\u8e2a\u72b6\u6001\uff08TASK_TRACED\uff09<\/strong>
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fork\u7cfb\u7edf\u8c03\u7528<\/h4>\n

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\u4e0a\u8ff0\u4e09\u4e2a\u7cfb\u7edf\u8c03\u7528\u6240\u5bf9\u5e94\u7684\u7cfb\u7edf\u8c03\u7528\u53f7\u5728linux\/include\/asm-i386\/unistd.h\u4e2d\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n

   #define __NR_restart_syscall      0\r\n   #define __NR_exit                 1\r\n   #define __NR_fork                 2\r\n   \u2026\u2026 \u2026\u2026\r\n   #define __NR_clone              120\r\n   \u2026\u2026 \u2026\u2026\r\n   #define __NR_vfork              190\r\n   \u2026\u2026 \u2026\u2026<\/pre>\n
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\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u5185\u6838\u4e2d\u63d0\u4f9b\u4e86\u4e0a\u8ff0\u4e09\u79cd\u4e0d\u540c\u7684\u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n
1\uff0e \u5185\u6838\u91c7\u7528\u5199\u65f6\u590d\u5236\u6280\u672f\u5bf9\u4f20\u7edf\u7684fork\u51fd\u6570\u8fdb\u884c\u4e86\u4e0b\u9762\u7684\u4f18\u5316\u3002\u5373\u5b50\u8fdb\u7a0b\u521b\u5efa\u540e\uff0c\u7236\u5b50\u4ee5\u53ea\u8bfb\u7684\u65b9\u5f0f\u5171\u4eab\u7236\u8fdb\u7a0b\u7684\u8d44\u6e90\uff08\u5e76\u4e0d\u5305\u62ec\u7236\u8fdb\u7a0b\u7684\u9875\u8868\u9879\uff09\u3002\u5f53\u5b50\u8fdb\u7a0b\u9700\u8981\u4fee\u6539\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u7684\u67d0\u4e00\u9875\u65f6\uff0c\u624d\u4e3a\u5b50\u8fdb\u7a0b\u590d\u5236\u8be5\u9875\u3002\u91c7\u7528\u8fd9\u6837\u7684\u6280\u672f\u53ef\u4ee5\u907f\u514d\u5bf9\u7236\u8fdb\u7a0b\u4e2d\u67d0\u4e9b\u6570\u636e\u4e0d\u5fc5\u8981\u7684\u590d\u5236\u3002<\/p>\n
2\uff0e \u4f7f\u7528vfork\u51fd\u6570\u521b\u5efa\u7684\u5b50\u8fdb\u7a0b\u4f1a\u5b8c\u5168\u5171\u4eab\u7236\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4\uff0c\u751a\u81f3\u662f\u7236\u8fdb\u7a0b\u7684\u9875\u8868\u9879\u3002\u7236\u5b50\u8fdb\u7a0b\u4efb\u610f\u4e00\u65b9\u5bf9\u4efb\u4f55\u6570\u636e\u7684\u4fee\u6539\u4f7f\u5f97\u53e6\u4e00\u65b9\u90fd\u53ef\u4ee5\u611f\u77e5\u5230\u3002\u4e3a\u4e86\u4f7f\u5f97\u53cc\u65b9\u4e0d\u53d7\u8fd9\u79cd\u5f71\u54cd\uff0cvfork\u51fd\u6570\u521b\u5efa\u4e86\u5b50\u8fdb\u7a0b\u540e\uff0c\u7236\u8fdb\u7a0b\u4fbf\u88ab\u963b\u585e\u76f4\u81f3\u5b50\u8fdb\u7a0b\u8c03\u7528\u4e86exec()\u6216exit()\u3002\u7531\u4e8e\u73b0\u5728fork\u51fd\u6570\u5f15\u5165\u4e86\u5199\u65f6\u590d\u5236\u6280\u672f\uff0c\u5728\u4e0d\u8003\u8651\u590d\u5236\u7236\u8fdb\u7a0b\u9875\u8868\u9879\u7684\u60c5\u51b5\u4e0b\uff0cvfork\u51fd\u6570\u51e0\u4e4e\u4e0d\u4f1a\u88ab\u4f7f\u7528\u3002<\/p>\n
3\uff0e clone\u51fd\u6570\u521b\u5efa\u5b50\u8fdb\u7a0b\u65f6\u7075\u6d3b\u5ea6\u6bd4\u8f83\u5927\uff0c\u56e0\u4e3a\u5b83\u53ef\u4ee5\u901a\u8fc7\u4f20\u9012\u4e0d\u540c\u7684\u53c2\u6570\u6765\u9009\u62e9\u6027\u7684\u590d\u5236\u7236\u8fdb\u7a0b\u7684\u8d44\u6e90\u3002\u5177\u4f53\u53c2\u6570\u53ef\u53c2\u89c1\u88681<\/p>\n
\u5c31\u50cf\u4e00\u5f00\u59cb\u6240\u5206\u6790\u7684\u90a3\u6837\uff0c\u7528\u6237\u7a0b\u5e8f\u5e76\u4e0d\u76f4\u63a5\u4f7f\u7528\u7cfb\u7edf\u8c03\u7528\uff0c\u800c\u662f\u901a\u8fc7C\u5e93\u4e2d\u7684API\u3002\u800c\u7cfb\u7edf\u8c03\u7528\u5728\u5185\u6838\u4e2d\u4e5f\u5e76\u4e0d\u662f\u76f4\u63a5\u5b9e\u73b0\u7684\uff0c\u800c\u662f\u901a\u8fc7\u8c03\u7528\u5404\u81ea\u5bf9\u5e94\u7684\u670d\u52a1\u4f8b\u7a0b\u3002\u7cfb\u7edf\u8c03\u7528fork\u3001vfork\u548cclone\u5728\u5185\u6838\u4e2d\u5bf9\u5e94\u7684\u670d\u52a1\u4f8b\u7a0b\u5206\u522b\u4e3asys_fork()\uff0csys_vfork()\u548csys_clone()\u3002\u56e0\u6b64\uff0c\u60f3\u8981\u4e86\u89e3fork\u7b49\u7cfb\u7edf\u8c03\u7528\u7684\u8be6\u7ec6\u6267\u884c\u8fc7\u7a0b\uff0c\u5c31\u5fc5\u987b\u67e5\u770b\u5b83\u4eec\u6240\u5bf9\u5e94\u7684\u5185\u6838\u51fd\u6570\uff08\u4e5f\u5c31\u662f\u670d\u52a1\u4f8b\u7a0b\uff09\u662f\u5982\u4f55\u5b9e\u73b0\u7684\u3002\u4e0a\u8ff0\u4e09\u4e2a\u7cfb\u7edf\u8c03\u7528\u5bf9\u5e94\u7684\u670d\u52a1\u4f8b\u7a0b\u5206\u522b\u5b9a\u4e49\u5728linux\/arch\/i386\/kernel\/process.c \u4e2d\uff0c\u5177\u4f53\u5982\u4e0b\uff1a<\/p>\n
asmlinkage int sys_fork(struct pt_regs regs)\r\n{\r\n\treturn do_fork(SIGCHLD, regs.esp, \u00aes, 0, NULL, NULL);\r\n}\r\n\r\nasmlinkage int sys_clone(struct pt_regs regs)\r\n{\r\n\tunsigned long clone_flags;\r\n\tunsigned long newsp;\r\n\tint __user *parent_tidptr, *child_tidptr;\r\n\r\n\tclone_flags = regs.ebx;\r\n\tnewsp = regs.ecx;\r\n\tparent_tidptr = (int __user *)regs.edx;\r\n\tchild_tidptr = (int __user *)regs.edi;\r\n\tif (!newsp)\r\n\t\tnewsp = regs.esp;\r\n\treturn do_fork(clone_flags, newsp, \u00aes, 0, parent_tidptr, child_tidptr);\r\n}\r\n\r\nasmlinkage int sys_vfork(struct pt_regs regs)\r\n{\r\n\treturn do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, \u00aes, 0, NULL, NULL);\r\n}<\/pre>\n
\u53ef\u4ee5\u770b\u5230do_fork()\u5747\u88ab\u4e0a\u8ff0\u4e09\u4e2a\u670d\u52a1\u4f8b\u7a0b\u8c03\u7528\u3002\u800c\u5728do_fork()\u5185\u90e8\u53c8\u8c03\u7528\u4e86copy_process()\uff0c\u56e0\u6b64\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u56fe2\u6765\u7406\u89e3\u4e0a\u8ff0\u7684\u8c03\u7528\u5173\u7cfb\u3002<\/p>\n
\"\"<\/a>\u00a0<\/strong><\/p>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u56fe2<\/strong>
\n\u4ece\u4e0a\u9762\u7684\u5206\u6790\u4e2d\uff0c\u6211\u4eec\u5df2\u7ecf\u660e\u786e\u4e86do_fork()\u548ccopy_process()\u662f\u672c\u6587\u7684\u4e3b\u8981\u5206\u6790\u5bf9\u8c61\u3002\u4f46\u662f\u5728\u8fd9\u4e4b\u524d\uff0c\u6211\u4eec\u6709\u5fc5\u8981\u5148\u5206\u6790\u4e00\u4e0b\u7528\u6237\u8fdb\u7a0b\u8fdb\u5165\u7cfb\u7edf\u8c03\u7528\u7684\u8fc7\u7a0b\u3002\u8be6\u89c1\u4e0b\u6587\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a5\u4e0b\u6765\u7684\u51e0\u7bc7\u6587\u7ae0\u5c06\u4f1a\u5206\u6790fork\u7cfb\u7edf\u8c03\u7528\u5728\u5185\u6838\u4e2d\u7684\u5b9e\u73b0\uff0c\u4ee5\u4f5c\u4e3a\u672c\u5b66\u671flinux\u64cd\u4f5c\u7cfb\u7edf\u8bfe\u7a0b\u603b\u7684\u5206\u6790\u62a5\u544a\u3002\u672c\u6587\u6240 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[110],"tags":[180,161,179],"class_list":["post-2103","post","type-post","status-publish","format-standard","hentry","category-linux","tag-fork","tag-161","tag-179"],"views":10297,"_links":{"self":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/2103","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/comments?post=2103"}],"version-history":[{"count":0,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/2103\/revisions"}],"wp:attachment":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/media?parent=2103"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/categories?post=2103"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/tags?post=2103"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}