{"id":1220,"date":"2012-02-07T23:33:29","date_gmt":"2012-02-07T14:33:29","guid":{"rendered":"http:\/\/peta.okechan.net\/blog\/?p=1220"},"modified":"2013-02-01T13:32:18","modified_gmt":"2013-02-01T04:32:18","slug":"xv6%e3%82%bd%e3%83%bc%e3%82%b9%e3%82%b3%e3%83%bc%e3%83%89%e3%83%aa%e3%83%bc%e3%83%87%e3%82%a3%e3%83%b3%e3%82%b0-%e3%81%9d%e3%81%ae2","status":"publish","type":"post","link":"https:\/\/peta.okechan.net\/blog\/archives\/1220","title":{"rendered":"[xv6 #2] Chapter 0 – Operating system interfaces – Code: Processes and memory"},"content":{"rendered":"

\u30c6\u30ad\u30b9\u30c8\u306e8\u301c10\u30da\u30fc\u30b8<\/p>\n

\u6982\u8981<\/h3>\n

xv6\u306e\u30d7\u30ed\u30bb\u30b9\u306f\u3001\u547d\u4ee4\u3068\u30c7\u30fc\u30bf\u3068\u30b9\u30bf\u30c3\u30af\u3092\u7f6e\u304f\u305f\u3081\u306e\u30e6\u30fc\u30b6\u30fc\u7a7a\u9593\u306e\u30e1\u30e2\u30ea\u9818\u57df\u3068\u3001\u30ab\u30fc\u30cd\u30eb\u3067\u7ba1\u7406\u3055\u308c\u308b\u30d7\u30ed\u30bb\u30b9\u306e\u72b6\u614b\u304b\u3089\u6210\u308b\u3002
\nxv6\u306f\u30bf\u30a4\u30e0\u30b7\u30a7\u30a2\u30ea\u30f3\u30b0\u3092\u63d0\u4f9b\u3057\u3066\u3044\u3066\u3001\u305d\u308c\u306f\u5b9f\u884c\u3092\u5f85\u3063\u3066\u308b\u30d7\u30ed\u30bb\u30b9\u7fa4\u306e\u9593\u3067\u4f7f\u3048\u308bCPU\u3092\u81ea\u52d5\u7684\u306b\u5207\u308a\u66ff\u3048\u308b\u3002\u30d7\u30ed\u30bb\u30b9\u304c\u5b9f\u884c\u3055\u308c\u3066\u306a\u3044\u3068\u304d\u306f\u305d\u306e\u30ec\u30b8\u30b9\u30bf\u306e\u5185\u5bb9\u3092\u4fdd\u5b58\u3057\u3066\u3001\u6b21\u306b\u30d7\u30ed\u30bb\u30b9\u304c\u518d\u958b\u3055\u308c\u308b\u3068\u304d\u306b\u8aad\u307f\u8fbc\u3080\u3002
\n\u3069\u306e\u30d7\u30ed\u30bb\u30b9\u3082\u4e00\u610f\u306b\u8b58\u5225\u53ef\u80fd\u306a\u6b63\u306e\u6574\u6570\u304c\u3064\u3044\u3066\u3066\u3001\u305d\u308c\u306f\u30d7\u30ed\u30bb\u30b9ID\u3082\u3057\u304f\u306fpid\u3068\u547c\u3070\u308c\u308b\u3002<\/p>\n

\u3042\u308b\u30d7\u30ed\u30bb\u30b9\u306f\u3001fork\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u3092\u4f7f\u3063\u3066\u65b0\u3057\u3044\u30d7\u30ed\u30bb\u30b9\u3092\u751f\u6210\u3059\u308b\u3053\u3068\u304c\u51fa\u6765\u308b\u3002
\nfork\u306f\u65b0\u3057\u3044\u30d7\u30ed\u30bb\u30b9\uff08\u5b50\u30d7\u30ed\u30bb\u30b9\u3068\u547c\u3070\u308c\u308b\uff09\u3092\u751f\u6210\u3057\u3001\u305d\u306e\u30d7\u30ed\u30bb\u30b9\u306f\u5143\u306e\u30d7\u30ed\u30bb\u30b9\uff08\u89aa\u30d7\u30ed\u30bb\u30b9\uff09\u3068\u5168\u304f\u540c\u3058\u30e1\u30e2\u30ea\u306e\u5185\u5bb9\u3092\u6301\u3064\u3002
\nfork\u306f\u89aa\u30d7\u30ed\u30bb\u30b9\u3067\u3082\u5b50\u30d7\u30ed\u30bb\u30b9\u3067\u3082\u8fd4\u308a\u5024\u3092\u8fd4\u3059\u3002
\n\u89aa\u30d7\u30ed\u30bb\u30b9\u3067\u306f\u3001\u5b50\u30d7\u30ed\u30bb\u30b9\u306epid\u3092\u8fd4\u3059\u3002
\n\u5b50\u30d7\u30ed\u30bb\u30b9\u3067\u306f\u3001\u30bc\u30ed\u3092\u8fd4\u3059\u3002
\n\u6b21\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u65ad\u7247\u306b\u3064\u3044\u3066\u8003\u3048\u3066\u307f\u3088\u3046\u3002<\/p>\n

\r\nint pid;\r\npid = fork();\r\nif(pid > 0){\r\n  printf("parent: child=%d\\n", pid);\r\n  pid = wait();\r\n  printf("child %d is done\\n", pid);\r\n} else if(pid == 0){\r\n  printf("child: exiting\\n");\r\n  exit();\r\n} else {\r\n  printf("fork error\\n");\r\n}\r\n<\/pre>\n
exit\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u305d\u308c\u3092\u547c\u3093\u3060\u30d7\u30ed\u30bb\u30b9\u306e\u5b9f\u884c\u3092\u6b62\u3081\u3066\u3001\u30e1\u30e2\u30ea\u3084\u958b\u3044\u3066\u308b\u30d5\u30a1\u30a4\u30eb\u306a\u3069\u306e\u30ea\u30bd\u30fc\u30b9\u3092\u89e3\u653e\u3059\u308b\u3002
\nwait\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u73fe\u5728\u306e\u30d7\u30ed\u30bb\u30b9\u306e\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u7d42\u4e86\u3057\u305f\u3068\u304d\u306b\u305d\u306epid\u3092\u8fd4\u3059\u3002
\n\u307e\u3060\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u7d42\u4e86\u3057\u3066\u306a\u304b\u3063\u305f\u3089\u7d42\u4e86\u3059\u308b\u307e\u3067\u5f85\u3064\u3002
\n\u4e0a\u8a18\u306e\u4f8b\u306f\u307e\u305a\u6b21\u306e\u3088\u3046\u306a\u7d50\u679c\u3092\u5370\u5b57\u3059\u308b\u3002<\/p>\n
\r\nparent: child=1234\r\nchild: exiting\r\n<\/pre>\n
\u89aa\u304b\u5b50\u3001\u3069\u3061\u3089\u306eprintf\u304c\u5148\u306b\u547c\u3070\u308c\u305f\u304b\u306b\u3088\u308b\u306e\u3067\u9806\u756a\u306f\u4e0a\u8a18\u306e\u9650\u308a\u3067\u306f\u306a\u3044\u3002
\n\u3067\u3001\u305d\u306e\u4e8c\u3064\u306e\u5370\u5b57\u306e\u3042\u3068\u3001\u5b50\u30d7\u30ed\u30bb\u30b9\u306f\u7d42\u4e86\u3057\u3001\u89aa\u30d7\u30ed\u30bb\u30b9\u306ewait\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u304c\u8fd4\u3063\u3066\u304f\u308b\u3002
\n\u305d\u306e\u7d50\u679c\u3001\u89aa\u30d7\u30ed\u30bb\u30b9\u306f\u3055\u3089\u306b\u4e0b\u8a18\u3092\u5370\u5b57\u3059\u308b\u3002<\/p>\n
\r\nparent: child 1234 is done\r\n<\/pre>\n
\u89aa\u30d7\u30ed\u30bb\u30b9\u3068\u5b50\u30d7\u30ed\u30bb\u30b9\u306f\u5185\u5bb9\u306f\u540c\u3058\u306a\u308c\u3069\u9055\u3046\u30e1\u30e2\u30ea\u9818\u57df\u3001\u9055\u3046\u30ec\u30b8\u30b9\u30bf\u3067\u5b9f\u884c\u3055\u308c\u308b\u306e\u3067\u3001\u4e00\u65b9\u306e\u5909\u66f4\u304c\u3082\u3046\u4e00\u65b9\u306b\u5f71\u97ff\u3057\u306a\u3044\u3053\u3068\u306b\u6ce8\u610f\u3002<\/p>\n
exec\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u547c\u3073\u51fa\u3057\u5143\u306e\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u3092\u65b0\u3057\u3044\u30e1\u30e2\u30ea\u30a4\u30e1\u30fc\u30b8\uff08\u30d5\u30a1\u30a4\u30eb\u30b7\u30b9\u30c6\u30e0\u306b\u7f6e\u304b\u308c\u305f\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u8aad\u307f\u8fbc\u307e\u308c\u305f\u3082\u306e\uff09\u3067\u7f6e\u304d\u63db\u3048\u308b\u3002
\n\u305d\u306e\u30d5\u30a1\u30a4\u30eb\u306f\u3001\u3069\u306e\u90e8\u5206\u304c\u547d\u4ee4\u3067\u3001\u3069\u306e\u90e8\u5206\u304c\u30c7\u30fc\u30bf\u304b\u3001\u3055\u3089\u306b\u3069\u306e\u547d\u4ee4\u304b\u3089\u958b\u59cb\u3059\u308b\u304b\u7b49\u3092\u6307\u5b9a\u3059\u308b\u3001\u7279\u5b9a\u306e\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u306b\u5f93\u3063\u3066\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002
\nxv6\u306f\u305d\u306e\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u3068\u3057\u3066ELF\u3068\u547c\u3070\u308c\u308b\u3082\u306e\u3092\u4f7f\u3046\u3002\uff08\u305d\u306e\u8a73\u7d30\u306b\u3064\u3044\u3066\u306fChapter 1\u3067\uff09
\nexec\u304c\u6210\u529f\u3057\u305f\u3089\u3001\u547c\u3073\u51fa\u3057\u5143\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3078\u306f\u623b\u3089\u306a\u3044\u3002
\n\u305d\u306e\u4ee3\u308f\u308a\u3001\u8aad\u307f\u8fbc\u307e\u308c\u305f\u547d\u4ee4\u3092ELF\u30d8\u30c3\u30c0\u306b\u5b9a\u7fa9\u3055\u308c\u305f\u30a8\u30f3\u30c8\u30ea\u30dd\u30a4\u30f3\u30c8\u304b\u3089\u5b9f\u884c\u3059\u308b\u3002
\nexec\u306f\u4e8c\u3064\u306e\u5f15\u6570\uff08\u5b9f\u884c\u53ef\u80fd\u306a\u30d5\u30a1\u30a4\u30eb\u306e\u540d\u524d\u3068\u305d\u306e\u5f15\u6570\u306e\u914d\u5217\uff09\u3092\u53d7\u3051\u53d6\u308b\u3002
\n\u4f8b\u3048\u3070\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u611f\u3058\u3067\u3042\u308b\u3002<\/p>\n
\r\nchar *argv[3];\r\nargv[0] = "echo";\r\nargv[1] = "hello";\r\nargv[2] = 0;\r\nexec("\/bin\/echo", argv);\r\nprintf("exec error\\n");\r\n<\/pre>\n
\u3053\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u3001\u81ea\u5206\u81ea\u8eab\u3092\u3001\u5f15\u6570 echo hello \u3068\u5171\u306b\u5b9f\u884c\u3055\u308c\u308b \/bin\/echo \u3068\u3044\u3046\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u7f6e\u304d\u63db\u3048\u308b\u3002
\n\u591a\u304f\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u6700\u521d\u306e\u5f15\u6570\u3092\u7121\u8996\u3059\u308b\u3002
\n\u7fd2\u6163\u7684\u306b\u6700\u521d\u306e\u5f15\u6570\u306f\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u540d\u524d\u3067\u3042\u308b\u3002<\/p>\n
xv6\u306e\u30b7\u30a7\u30eb\u306f\u3001\u4ee5\u4e0a\u306e\u3088\u3046\u306a\u547c\u3073\u51fa\u3057\u3092\u4f7f\u3063\u3066\u3001\u30e6\u30fc\u30b6\u30fc\u306e\u4ee3\u308f\u308a\u306b\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u5b9f\u884c\u3059\u308b\u3002
\n\u30b7\u30a7\u30eb\u306e\u4e3b\u306a\u69cb\u9020\u306f\u30b7\u30f3\u30d7\u30eb\u3067\u3042\u308b\u3002\uff08sh.c\u306emain\u95a2\u6570\u53c2\u7167\u3002\u4ee5\u4e0b\u306b\u3068\u308a\u3042\u3048\u305a\u8f09\u305b\u3068\u304d\u307e\u3059\u3002\uff09<\/p>\n
\r\nint\r\nmain(void)\r\n{\r\n  static char buf[100];\r\n  int fd;\r\n  \r\n  \/\/ Assumes three file descriptors open.\r\n  while((fd = open("console", O_RDWR)) >= 0){\r\n    if(fd >= 3){\r\n      close(fd);\r\n      break;\r\n    }\r\n  }\r\n  \r\n  \/\/ Read and run input commands.\r\n  while(getcmd(buf, sizeof(buf)) >= 0){\r\n    if(buf[0] == 'c' && buf[1] == 'd' && buf[2] == ' '){\r\n      \/\/ Clumsy but will have to do for now.\r\n      \/\/ Chdir has no effect on the parent if run in the child.\r\n      buf[strlen(buf)-1] = 0;  \/\/ chop \\n\r\n      if(chdir(buf+3) < 0)\r\n        printf(2, "cannot cd %s\\n", buf+3);\r\n      continue;\r\n    }\r\n    if(fork1() == 0)\r\n      runcmd(parsecmd(buf));\r\n    wait();\r\n  }\r\n  exit();\r\n}\r\n<\/pre>\n
\u30e1\u30a4\u30f3\u306e\u30eb\u30fc\u30d7\u3067getcmd\u3092\u4f7f\u3063\u3066\u30b3\u30de\u30f3\u30c9\u30e9\u30a4\u30f3\u304b\u3089\u5165\u529b\u3092\u8aad\u307f\u53d6\u3063\u3066\u3044\u308b\u3002
\n\u305d\u3057\u3066fork\u3092\u547c\u3093\u3067\u3001\u5225\u306e\u30b7\u30a7\u30eb\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u751f\u6210\u3059\u308b\u3002
\n\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u30b3\u30de\u30f3\u30c9\u3092\u5b9f\u884c\u3057\u3066\u308b\u9593\u3001\u89aa\u306e\u30b7\u30a7\u30eb\uff08\u89aa\u30d7\u30ed\u30bb\u30b9\uff09\u306fwait\u3092\u547c\u3093\u3067\u5f85\u3064\u3002
\n\u4f8b\u3048\u3070\u3001\u3082\u3057\u30e6\u30fc\u30b6\u304c\u304c”echo hello”\u3068\u5165\u529b\u3057\u305f\u3089\u3001runcmd\u306f”echo hello”\u3092\u5f15\u6570\u3068\u3057\u3066\u547c\u3070\u308c\u308b\u3002
\nruncmd\u306f\u4ee5\u4e0b\u306e\u3068\u304a\u308a\u3002\uff08sh.c\u306eruncmd\u95a2\u6570\uff09<\/p>\n
\r\nvoid\r\nruncmd(struct cmd *cmd)\r\n{\r\n  int p[2];\r\n  struct backcmd *bcmd;\r\n  struct execcmd *ecmd;\r\n  struct listcmd *lcmd;\r\n  struct pipecmd *pcmd;\r\n  struct redircmd *rcmd;\r\n\r\n  if(cmd == 0)\r\n    exit();\r\n  \r\n  switch(cmd->type){\r\n  default:\r\n    panic("runcmd");\r\n\r\n  case EXEC:\r\n    ecmd = (struct execcmd*)cmd;\r\n    if(ecmd->argv[0] == 0)\r\n      exit();\r\n    exec(ecmd->argv[0], ecmd->argv);\r\n    printf(2, "exec %s failed\\n", ecmd->argv[0]);\r\n    break;\r\n\r\n  case REDIR:\r\n    rcmd = (struct redircmd*)cmd;\r\n    close(rcmd->fd);\r\n    if(open(rcmd->file, rcmd->mode) < 0){\r\n      printf(2, "open %s failed\\n", rcmd->file);\r\n      exit();\r\n    }\r\n    runcmd(rcmd->cmd);\r\n    break;\r\n\r\n  case LIST:\r\n    lcmd = (struct listcmd*)cmd;\r\n    if(fork1() == 0)\r\n      runcmd(lcmd->left);\r\n    wait();\r\n    runcmd(lcmd->right);\r\n    break;\r\n\r\n  case PIPE:\r\n    pcmd = (struct pipecmd*)cmd;\r\n    if(pipe(p) < 0)\r\n      panic("pipe");\r\n    if(fork1() == 0){\r\n      close(1);\r\n      dup(p[1]);\r\n      close(p[0]);\r\n      close(p[1]);\r\n      runcmd(pcmd->left);\r\n    }\r\n    if(fork1() == 0){\r\n      close(0);\r\n      dup(p[0]);\r\n      close(p[0]);\r\n      close(p[1]);\r\n      runcmd(pcmd->right);\r\n    }\r\n    close(p[0]);\r\n    close(p[1]);\r\n    wait();\r\n    wait();\r\n    break;\r\n    \r\n  case BACK:\r\n    bcmd = (struct backcmd*)cmd;\r\n    if(fork1() == 0)\r\n      runcmd(bcmd->cmd);\r\n    break;\r\n  }\r\n  exit();\r\n}\r\n<\/pre>\n
runcmd\u306f\u5b9f\u969b\u306e\u30b3\u30de\u30f3\u30c9\u3092\u5b9f\u884c\u3059\u308b\u3002
\n“echo hello”\u306e\u5834\u5408\u3001runcmd\u95a2\u6570\u306e\u4e2d\u306ecase EXEC:\u306e\u4e2d\u306eexec\u304c\u547c\u3070\u308c\u308b\u3002
\n\u3082\u3057exec\u304c\u6210\u529f\u3057\u305f\u3089\u3001\u305d\u306e\u5b50\u30d7\u30ed\u30bb\u30b9\u306fruncmd\u3092\u9014\u4e2d\u3067\u6295\u3052\u51fa\u3057\u3066echo\u306e\uff08\u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u8aad\u307f\u8fbc\u3093\u3060\uff09\u547d\u4ee4\u3092\u5b9f\u884c\u3059\u308b\u3002
\n\u305d\u3057\u3066\u3069\u3053\u304b\u306e\u6bb5\u968e\u3067echo\u306fexit\u3092\u547c\u3076\u3060\u308d\u3046\u3002
\n\u305d\u3046\u3059\u308b\u3053\u3068\u3067\u89aa\u30d7\u30ed\u30bb\u30b9\u306fmain\u95a2\u6570\u306ewait\u304b\u3089\u5fa9\u5e30\u3059\u308b\u4e8b\u304c\u51fa\u6765\u308b\u3002
\nfork\u3068exec\u304c\u306a\u305c\u4e00\u5ea6\u306e\u547c\u3073\u51fa\u3057\u3067\u884c\u3048\u306a\u3044\u304b\u4e0d\u601d\u8b70\u306b\u601d\u3046\u304b\u3082\u3057\u308c\u306a\u3044\u3002
\n\u30d7\u30ed\u30bb\u30b9\u306e\u751f\u6210\u3068\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30ed\u30fc\u30c9\u304c\u5206\u304b\u308c\u3066\u308b\u4e8b\u304c\u8ce2\u3044\u30c7\u30b6\u30a4\u30f3\u3060\u3068\u5f8c\u3067\u6c17\u3065\u304f\u3060\u308d\u3046\u3002<\/p>\n
xv6\u306f\u6697\u9ed9\u306e\u3046\u3061\u306b\u6700\u5927\u91cf\u306e\u30e6\u30fc\u30b6\u7a7a\u9593\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\nfork\u306f\u89aa\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u306e\u8907\u88fd\u306e\u305f\u3081\u306b\u5fc5\u8981\u3068\u306a\u308b\u5b50\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\n\u305d\u3057\u3066exec\u306f\u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u3092\u4fdd\u6301\u3059\u308b\u306e\u306b\u5341\u5206\u306a\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\n\uff08malloc\u306a\u3069\u3067\uff09\u5b9f\u884c\u4e2d\u306b\u30e1\u30e2\u30ea\u304c\u3055\u3089\u306b\u5fc5\u8981\u306b\u306a\u3063\u305f\u30d7\u30ed\u30bb\u30b9\u306f\u3001\u30c7\u30fc\u30bf\u30e1\u30e2\u30ea\u3092n\u30d0\u30a4\u30c8\u307e\u3067\u5897\u3084\u3059\u305f\u3081\u306bsbrk(n)\u3092\u547c\u3076\u3053\u3068\u304c\u3067\u304d\u308b\u3002
\nsbrk\u306f\u65b0\u3057\u3044\u30e1\u30e2\u30ea\u306e\u5834\u6240\u3092\u8fd4\u3059\u3002<\/p>\n
xv6\u306f\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u306f\u63d0\u4f9b\u3057\u306a\u3044\u306e\u3067\u3001\u30d5\u30a1\u30a4\u30eb\u3084\u30d7\u30ed\u30bb\u30b9\u306b\u30e6\u30fc\u30b6\u3092\u7d50\u3073\u3064\u3051\u3066\u4ed6\u306e\u30e6\u30fc\u30b6\u304b\u3089\u4fdd\u8b77\u3059\u308b\u3068\u3044\u3046\u4e8b\u306f\u51fa\u6765\u306a\u3044\u3002
\nUnix\u7684\u306b\u8a00\u3048\u3070\u3001\u5168\u3066\u306exv6\u306e\u30d7\u30ed\u30bb\u30b9\u306froot\u6a29\u9650\u3067\u5b9f\u884c\u3055\u308c\u308b\u3002<\/p>\n
\u611f\u60f3<\/h3>\n
\u610f\u5916\u3060\u306a\u3068\u601d\u3063\u305f\u306e\u304cexec\u306e\u52d5\u4f5c\u3067\u3059\u3002
\n\u547c\u3073\u51fa\u3057\u5143\u306e\u30e1\u30e2\u30ea\u8aad\u307f\u8fbc\u3093\u3060\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u5b9f\u884c\u30a4\u30e1\u30fc\u30b8\u3067\u201d\u7f6e\u304d\u63db\u3048\u308b\u201d\u30ef\u30b1\u3067\u3059\u306d\u3002
\n\u306a\u306e\u3067\u305d\u306e\u524d\u306bfork\u3057\u3066\u308b\u3068\u3002
\nexec\u3067\u305d\u306e\u307e\u307e\u5225\u306e\u30d7\u30ed\u30bb\u30b9\u3092\u958b\u59cb\u51fa\u6765\u308c\u3070fork\u3059\u308b\u5fc5\u8981\u3082\u306a\u3044\u3068\u601d\u3046\u3093\u3067\u3059\u304c\u3001\u30c6\u30ad\u30b9\u30c8\u306b\u3082fork\u3068exec\u304c\u5206\u304b\u308c\u3066\u308b\u306e\u306b\u306f\u7406\u7531\u304c\u3042\u308b\u3002\u305d\u308c\u306f\u5f8c\u307b\u3069\u4e5e\u3046\u3054\u671f\u5f85\u3068\u66f8\u3044\u3066\u3042\u308b\u306e\u3067\u8ffd\u3005\u5206\u304b\u3063\u3066\u304f\u308b\u306e\u3067\u3057\u3087\u3046\u3002<\/p>\n
\u30bd\u30fc\u30b9\u304c\u3061\u3087\u308d\u3063\u3068\u51fa\u3066\u304d\u307e\u3057\u305f\u3002
\n\u30b7\u30a7\u30eb\u306e\u30bd\u30fc\u30b9\u306e\u4e00\u90e8\u3067\u3059\u3002
\n\u524d\u56de\u3001\u30b7\u30a7\u30eb\u306f\u30e6\u30fc\u30b6\u7a7a\u9593\u3067\u5b9f\u884c\u3055\u308c\u308b\u901a\u5e38\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u3042\u308b\u3001\u3068\u66f8\u304b\u308c\u3066\u307e\u3057\u305f\u306e\u3067\u3001\u307e\u3060\u30ab\u30fc\u30cd\u30eb\u90e8\u5206\u3092\u8aad\u307f\u59cb\u3081\u308b\u3068\u3044\u3046\u3068\u3053\u308d\u307e\u3067\u306f\u81f3\u3063\u3066\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
\u3042\u3068\u3001xv6\u306b\u306f\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u304c\u306a\u3044\u3068\u66f8\u304b\u308c\u3066\u3044\u307e\u3059\u3002
\n\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u304c\u3042\u308b\u3068\u3001\u7ba1\u7406\u3084\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u306e\u305f\u3081\u306b\u8272\u3005\u306a\u6982\u5ff5\u3092\u5c0e\u5165\u305b\u3056\u308b\u3092\u5f97\u305a\u3001\u30bd\u30fc\u30b9\u304c\u8907\u96d1\u3067\u3088\u308a\u7406\u89e3\u3057\u3065\u3089\u3044\u3082\u306e\u306b\u306a\u308b\u306e\u3067\u3057\u3087\u3046\u3002
\n\u305d\u306e\u3078\u3093\u6c17\u306b\u3057\u306a\u304f\u3066\u3044\u3044\u3068\u3044\u3046\u3053\u3068\u306f\u3001\u3068\u308a\u3042\u3048\u305a\u8aad\u3080\u3068\u3044\u3046\u8eab\u306b\u3068\u3063\u3066\u306f\u3042\u308a\u304c\u305f\u3044\u3053\u3068\u3067\u3059\u3002<\/p>\n
sh.c\u306eruncmd\u95a2\u6570\u3092\u898b\u308b\u3068\u3001switch\u306e\u6700\u521d\u306bdefault\u3092\u7f6e\u3044\u3066\u3042\u308a\u307e\u3059\u3002
\ndefault\u3063\u3066\u6700\u521d\u3067\u3082\u3044\u3044\u306e\u304b\u30fc\uff01\u3063\u3066\u306e\u304c\u4eca\u56de\u4e00\u756a\u306e\u9a5a\u304d\u3067\u3059\u3002<\/p>\n
\u307b\u3068\u3093\u3069\u8a33\u3057\u3066\u3057\u307e\u3044\u307e\u3057\u305f\u3002
\n\u305f\u3076\u3093\u4eca\u56de\u306b\u9650\u3089\u305a\u3067\u3059\u304c\u3001\u7ffb\u8a33\u306f\u8d85\u9069\u5f53\u3067\u3059\u306e\u3067\u3054\u6ce8\u610f\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u30c6\u30ad\u30b9\u30c8\u306e8\u301c10\u30da\u30fc\u30b8<\/p>\n
\u6982\u8981<\/h3>\n
xv6\u306e\u30d7\u30ed\u30bb\u30b9\u306f\u3001\u547d\u4ee4\u3068\u30c7\u30fc\u30bf\u3068\u30b9\u30bf\u30c3\u30af\u3092\u7f6e\u304f\u305f\u3081\u306e\u30e6\u30fc\u30b6\u30fc\u7a7a\u9593\u306e\u30e1\u30e2\u30ea\u9818\u57df\u3068\u3001\u30ab\u30fc\u30cd\u30eb\u3067\u7ba1\u7406\u3055\u308c\u308b\u30d7\u30ed\u30bb\u30b9\u306e\u72b6\u614b\u304b\u3089\u6210\u308b\u3002
\nxv6\u306f\u30bf\u30a4\u30e0\u30b7\u30a7\u30a2\u30ea\u30f3\u30b0\u3092\u63d0\u4f9b\u3057\u3066\u3044\u3066\u3001\u305d\u308c\u306f\u5b9f\u884c\u3092\u5f85\u3063\u3066\u308b\u30d7\u30ed\u30bb\u30b9\u7fa4\u306e\u9593\u3067\u4f7f\u3048\u308bCPU\u3092\u81ea\u52d5\u7684\u306b\u5207\u308a\u66ff\u3048\u308b\u3002\u30d7\u30ed\u30bb\u30b9\u304c\u5b9f\u884c\u3055\u308c\u3066\u306a\u3044\u3068\u304d\u306f\u305d\u306e\u30ec\u30b8\u30b9\u30bf\u306e\u5185\u5bb9\u3092\u4fdd\u5b58\u3057\u3066\u3001\u6b21\u306b\u30d7\u30ed\u30bb\u30b9\u304c\u518d\u958b\u3055\u308c\u308b\u3068\u304d\u306b\u8aad\u307f\u8fbc\u3080\u3002
\n\u3069\u306e\u30d7\u30ed\u30bb\u30b9\u3082\u4e00\u610f\u306b\u8b58\u5225\u53ef\u80fd\u306a\u6b63\u306e\u6574\u6570\u304c\u3064\u3044\u3066\u3066\u3001\u305d\u308c\u306f\u30d7\u30ed\u30bb\u30b9ID\u3082\u3057\u304f\u306fpid\u3068\u547c\u3070\u308c\u308b\u3002<\/p>\n
\u3042\u308b\u30d7\u30ed\u30bb\u30b9\u306f\u3001fork\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u3092\u4f7f\u3063\u3066\u65b0\u3057\u3044\u30d7\u30ed\u30bb\u30b9\u3092\u751f\u6210\u3059\u308b\u3053\u3068\u304c\u51fa\u6765\u308b\u3002
\nfork\u306f\u65b0\u3057\u3044\u30d7\u30ed\u30bb\u30b9\uff08\u5b50\u30d7\u30ed\u30bb\u30b9\u3068\u547c\u3070\u308c\u308b\uff09\u3092\u751f\u6210\u3057\u3001\u305d\u306e\u30d7\u30ed\u30bb\u30b9\u306f\u5143\u306e\u30d7\u30ed\u30bb\u30b9\uff08\u89aa\u30d7\u30ed\u30bb\u30b9\uff09\u3068\u5168\u304f\u540c\u3058\u30e1\u30e2\u30ea\u306e\u5185\u5bb9\u3092\u6301\u3064\u3002
\nfork\u306f\u89aa\u30d7\u30ed\u30bb\u30b9\u3067\u3082\u5b50\u30d7\u30ed\u30bb\u30b9\u3067\u3082\u8fd4\u308a\u5024\u3092\u8fd4\u3059\u3002
\n\u89aa\u30d7\u30ed\u30bb\u30b9\u3067\u306f\u3001\u5b50\u30d7\u30ed\u30bb\u30b9\u306epid\u3092\u8fd4\u3059\u3002
\n\u5b50\u30d7\u30ed\u30bb\u30b9\u3067\u306f\u3001\u30bc\u30ed\u3092\u8fd4\u3059\u3002
\n\u6b21\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u65ad\u7247\u306b\u3064\u3044\u3066\u8003\u3048\u3066\u307f\u3088\u3046\u3002<\/p>\n
\r\nint pid;\r\npid = fork();\r\nif(pid > 0){\r\n  printf("parent: child=%d\\n", pid);\r\n  pid = wait();\r\n  printf("child %d is done\\n", pid);\r\n} else if(pid == 0){\r\n  printf("child: exiting\\n");\r\n  exit();\r\n} else {\r\n  printf("fork error\\n");\r\n}\r\n<\/pre>\n
exit\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u305d\u308c\u3092\u547c\u3093\u3060\u30d7\u30ed\u30bb\u30b9\u306e\u5b9f\u884c\u3092\u6b62\u3081\u3066\u3001\u30e1\u30e2\u30ea\u3084\u958b\u3044\u3066\u308b\u30d5\u30a1\u30a4\u30eb\u306a\u3069\u306e\u30ea\u30bd\u30fc\u30b9\u3092\u89e3\u653e\u3059\u308b\u3002
\nwait\u3068\u3044\u3046\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u73fe\u5728\u306e\u30d7\u30ed\u30bb\u30b9\u306e\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u7d42\u4e86\u3057\u305f\u3068\u304d\u306b\u305d\u306epid\u3092\u8fd4\u3059\u3002
\n\u307e\u3060\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u7d42\u4e86\u3057\u3066\u306a\u304b\u3063\u305f\u3089\u7d42\u4e86\u3059\u308b\u307e\u3067\u5f85\u3064\u3002
\n\u4e0a\u8a18\u306e\u4f8b\u306f\u307e\u305a\u6b21\u306e\u3088\u3046\u306a\u7d50\u679c\u3092\u5370\u5b57\u3059\u308b\u3002<\/p>\n
\r\nparent: child=1234\r\nchild: exiting\r\n<\/pre>\n
\u89aa\u304b\u5b50\u3001\u3069\u3061\u3089\u306eprintf\u304c\u5148\u306b\u547c\u3070\u308c\u305f\u304b\u306b\u3088\u308b\u306e\u3067\u9806\u756a\u306f\u4e0a\u8a18\u306e\u9650\u308a\u3067\u306f\u306a\u3044\u3002
\n\u3067\u3001\u305d\u306e\u4e8c\u3064\u306e\u5370\u5b57\u306e\u3042\u3068\u3001\u5b50\u30d7\u30ed\u30bb\u30b9\u306f\u7d42\u4e86\u3057\u3001\u89aa\u30d7\u30ed\u30bb\u30b9\u306ewait\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u304c\u8fd4\u3063\u3066\u304f\u308b\u3002
\n\u305d\u306e\u7d50\u679c\u3001\u89aa\u30d7\u30ed\u30bb\u30b9\u306f\u3055\u3089\u306b\u4e0b\u8a18\u3092\u5370\u5b57\u3059\u308b\u3002<\/p>\n
\r\nparent: child 1234 is done\r\n<\/pre>\n
\u89aa\u30d7\u30ed\u30bb\u30b9\u3068\u5b50\u30d7\u30ed\u30bb\u30b9\u306f\u5185\u5bb9\u306f\u540c\u3058\u306a\u308c\u3069\u9055\u3046\u30e1\u30e2\u30ea\u9818\u57df\u3001\u9055\u3046\u30ec\u30b8\u30b9\u30bf\u3067\u5b9f\u884c\u3055\u308c\u308b\u306e\u3067\u3001\u4e00\u65b9\u306e\u5909\u66f4\u304c\u3082\u3046\u4e00\u65b9\u306b\u5f71\u97ff\u3057\u306a\u3044\u3053\u3068\u306b\u6ce8\u610f\u3002<\/p>\n
exec\u30b7\u30b9\u30c6\u30e0\u30b3\u30fc\u30eb\u306f\u3001\u547c\u3073\u51fa\u3057\u5143\u306e\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u3092\u65b0\u3057\u3044\u30e1\u30e2\u30ea\u30a4\u30e1\u30fc\u30b8\uff08\u30d5\u30a1\u30a4\u30eb\u30b7\u30b9\u30c6\u30e0\u306b\u7f6e\u304b\u308c\u305f\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u8aad\u307f\u8fbc\u307e\u308c\u305f\u3082\u306e\uff09\u3067\u7f6e\u304d\u63db\u3048\u308b\u3002
\n\u305d\u306e\u30d5\u30a1\u30a4\u30eb\u306f\u3001\u3069\u306e\u90e8\u5206\u304c\u547d\u4ee4\u3067\u3001\u3069\u306e\u90e8\u5206\u304c\u30c7\u30fc\u30bf\u304b\u3001\u3055\u3089\u306b\u3069\u306e\u547d\u4ee4\u304b\u3089\u958b\u59cb\u3059\u308b\u304b\u7b49\u3092\u6307\u5b9a\u3059\u308b\u3001\u7279\u5b9a\u306e\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u306b\u5f93\u3063\u3066\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002
\nxv6\u306f\u305d\u306e\u30d5\u30a9\u30fc\u30de\u30c3\u30c8\u3068\u3057\u3066ELF\u3068\u547c\u3070\u308c\u308b\u3082\u306e\u3092\u4f7f\u3046\u3002\uff08\u305d\u306e\u8a73\u7d30\u306b\u3064\u3044\u3066\u306fChapter 1\u3067\uff09
\nexec\u304c\u6210\u529f\u3057\u305f\u3089\u3001\u547c\u3073\u51fa\u3057\u5143\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3078\u306f\u623b\u3089\u306a\u3044\u3002
\n\u305d\u306e\u4ee3\u308f\u308a\u3001\u8aad\u307f\u8fbc\u307e\u308c\u305f\u547d\u4ee4\u3092ELF\u30d8\u30c3\u30c0\u306b\u5b9a\u7fa9\u3055\u308c\u305f\u30a8\u30f3\u30c8\u30ea\u30dd\u30a4\u30f3\u30c8\u304b\u3089\u5b9f\u884c\u3059\u308b\u3002
\nexec\u306f\u4e8c\u3064\u306e\u5f15\u6570\uff08\u5b9f\u884c\u53ef\u80fd\u306a\u30d5\u30a1\u30a4\u30eb\u306e\u540d\u524d\u3068\u305d\u306e\u5f15\u6570\u306e\u914d\u5217\uff09\u3092\u53d7\u3051\u53d6\u308b\u3002
\n\u4f8b\u3048\u3070\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u611f\u3058\u3067\u3042\u308b\u3002<\/p>\n
\r\nchar *argv[3];\r\nargv[0] = "echo";\r\nargv[1] = "hello";\r\nargv[2] = 0;\r\nexec("\/bin\/echo", argv);\r\nprintf("exec error\\n");\r\n<\/pre>\n
\u3053\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u3001\u81ea\u5206\u81ea\u8eab\u3092\u3001\u5f15\u6570 echo hello \u3068\u5171\u306b\u5b9f\u884c\u3055\u308c\u308b \/bin\/echo \u3068\u3044\u3046\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u7f6e\u304d\u63db\u3048\u308b\u3002
\n\u591a\u304f\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u6700\u521d\u306e\u5f15\u6570\u3092\u7121\u8996\u3059\u308b\u3002
\n\u7fd2\u6163\u7684\u306b\u6700\u521d\u306e\u5f15\u6570\u306f\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u540d\u524d\u3067\u3042\u308b\u3002<\/p>\n
xv6\u306e\u30b7\u30a7\u30eb\u306f\u3001\u4ee5\u4e0a\u306e\u3088\u3046\u306a\u547c\u3073\u51fa\u3057\u3092\u4f7f\u3063\u3066\u3001\u30e6\u30fc\u30b6\u30fc\u306e\u4ee3\u308f\u308a\u306b\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u5b9f\u884c\u3059\u308b\u3002
\n\u30b7\u30a7\u30eb\u306e\u4e3b\u306a\u69cb\u9020\u306f\u30b7\u30f3\u30d7\u30eb\u3067\u3042\u308b\u3002\uff08sh.c\u306emain\u95a2\u6570\u53c2\u7167\u3002\u4ee5\u4e0b\u306b\u3068\u308a\u3042\u3048\u305a\u8f09\u305b\u3068\u304d\u307e\u3059\u3002\uff09<\/p>\n
\r\nint\r\nmain(void)\r\n{\r\n  static char buf[100];\r\n  int fd;\r\n  \r\n  \/\/ Assumes three file descriptors open.\r\n  while((fd = open("console", O_RDWR)) >= 0){\r\n    if(fd >= 3){\r\n      close(fd);\r\n      break;\r\n    }\r\n  }\r\n  \r\n  \/\/ Read and run input commands.\r\n  while(getcmd(buf, sizeof(buf)) >= 0){\r\n    if(buf[0] == 'c' && buf[1] == 'd' && buf[2] == ' '){\r\n      \/\/ Clumsy but will have to do for now.\r\n      \/\/ Chdir has no effect on the parent if run in the child.\r\n      buf[strlen(buf)-1] = 0;  \/\/ chop \\n\r\n      if(chdir(buf+3) < 0)\r\n        printf(2, "cannot cd %s\\n", buf+3);\r\n      continue;\r\n    }\r\n    if(fork1() == 0)\r\n      runcmd(parsecmd(buf));\r\n    wait();\r\n  }\r\n  exit();\r\n}\r\n<\/pre>\n
\u30e1\u30a4\u30f3\u306e\u30eb\u30fc\u30d7\u3067getcmd\u3092\u4f7f\u3063\u3066\u30b3\u30de\u30f3\u30c9\u30e9\u30a4\u30f3\u304b\u3089\u5165\u529b\u3092\u8aad\u307f\u53d6\u3063\u3066\u3044\u308b\u3002
\n\u305d\u3057\u3066fork\u3092\u547c\u3093\u3067\u3001\u5225\u306e\u30b7\u30a7\u30eb\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u751f\u6210\u3059\u308b\u3002
\n\u5b50\u30d7\u30ed\u30bb\u30b9\u304c\u30b3\u30de\u30f3\u30c9\u3092\u5b9f\u884c\u3057\u3066\u308b\u9593\u3001\u89aa\u306e\u30b7\u30a7\u30eb\uff08\u89aa\u30d7\u30ed\u30bb\u30b9\uff09\u306fwait\u3092\u547c\u3093\u3067\u5f85\u3064\u3002
\n\u4f8b\u3048\u3070\u3001\u3082\u3057\u30e6\u30fc\u30b6\u304c\u304c”echo hello”\u3068\u5165\u529b\u3057\u305f\u3089\u3001runcmd\u306f”echo hello”\u3092\u5f15\u6570\u3068\u3057\u3066\u547c\u3070\u308c\u308b\u3002
\nruncmd\u306f\u4ee5\u4e0b\u306e\u3068\u304a\u308a\u3002\uff08sh.c\u306eruncmd\u95a2\u6570\uff09<\/p>\n
\r\nvoid\r\nruncmd(struct cmd *cmd)\r\n{\r\n  int p[2];\r\n  struct backcmd *bcmd;\r\n  struct execcmd *ecmd;\r\n  struct listcmd *lcmd;\r\n  struct pipecmd *pcmd;\r\n  struct redircmd *rcmd;\r\n\r\n  if(cmd == 0)\r\n    exit();\r\n  \r\n  switch(cmd->type){\r\n  default:\r\n    panic("runcmd");\r\n\r\n  case EXEC:\r\n    ecmd = (struct execcmd*)cmd;\r\n    if(ecmd->argv[0] == 0)\r\n      exit();\r\n    exec(ecmd->argv[0], ecmd->argv);\r\n    printf(2, "exec %s failed\\n", ecmd->argv[0]);\r\n    break;\r\n\r\n  case REDIR:\r\n    rcmd = (struct redircmd*)cmd;\r\n    close(rcmd->fd);\r\n    if(open(rcmd->file, rcmd->mode) < 0){\r\n      printf(2, "open %s failed\\n", rcmd->file);\r\n      exit();\r\n    }\r\n    runcmd(rcmd->cmd);\r\n    break;\r\n\r\n  case LIST:\r\n    lcmd = (struct listcmd*)cmd;\r\n    if(fork1() == 0)\r\n      runcmd(lcmd->left);\r\n    wait();\r\n    runcmd(lcmd->right);\r\n    break;\r\n\r\n  case PIPE:\r\n    pcmd = (struct pipecmd*)cmd;\r\n    if(pipe(p) < 0)\r\n      panic("pipe");\r\n    if(fork1() == 0){\r\n      close(1);\r\n      dup(p[1]);\r\n      close(p[0]);\r\n      close(p[1]);\r\n      runcmd(pcmd->left);\r\n    }\r\n    if(fork1() == 0){\r\n      close(0);\r\n      dup(p[0]);\r\n      close(p[0]);\r\n      close(p[1]);\r\n      runcmd(pcmd->right);\r\n    }\r\n    close(p[0]);\r\n    close(p[1]);\r\n    wait();\r\n    wait();\r\n    break;\r\n    \r\n  case BACK:\r\n    bcmd = (struct backcmd*)cmd;\r\n    if(fork1() == 0)\r\n      runcmd(bcmd->cmd);\r\n    break;\r\n  }\r\n  exit();\r\n}\r\n<\/pre>\n
runcmd\u306f\u5b9f\u969b\u306e\u30b3\u30de\u30f3\u30c9\u3092\u5b9f\u884c\u3059\u308b\u3002
\n“echo hello”\u306e\u5834\u5408\u3001runcmd\u95a2\u6570\u306e\u4e2d\u306ecase EXEC:\u306e\u4e2d\u306eexec\u304c\u547c\u3070\u308c\u308b\u3002
\n\u3082\u3057exec\u304c\u6210\u529f\u3057\u305f\u3089\u3001\u305d\u306e\u5b50\u30d7\u30ed\u30bb\u30b9\u306fruncmd\u3092\u9014\u4e2d\u3067\u6295\u3052\u51fa\u3057\u3066echo\u306e\uff08\u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u304b\u3089\u8aad\u307f\u8fbc\u3093\u3060\uff09\u547d\u4ee4\u3092\u5b9f\u884c\u3059\u308b\u3002
\n\u305d\u3057\u3066\u3069\u3053\u304b\u306e\u6bb5\u968e\u3067echo\u306fexit\u3092\u547c\u3076\u3060\u308d\u3046\u3002
\n\u305d\u3046\u3059\u308b\u3053\u3068\u3067\u89aa\u30d7\u30ed\u30bb\u30b9\u306fmain\u95a2\u6570\u306ewait\u304b\u3089\u5fa9\u5e30\u3059\u308b\u4e8b\u304c\u51fa\u6765\u308b\u3002
\nfork\u3068exec\u304c\u306a\u305c\u4e00\u5ea6\u306e\u547c\u3073\u51fa\u3057\u3067\u884c\u3048\u306a\u3044\u304b\u4e0d\u601d\u8b70\u306b\u601d\u3046\u304b\u3082\u3057\u308c\u306a\u3044\u3002
\n\u30d7\u30ed\u30bb\u30b9\u306e\u751f\u6210\u3068\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30ed\u30fc\u30c9\u304c\u5206\u304b\u308c\u3066\u308b\u4e8b\u304c\u8ce2\u3044\u30c7\u30b6\u30a4\u30f3\u3060\u3068\u5f8c\u3067\u6c17\u3065\u304f\u3060\u308d\u3046\u3002<\/p>\n
xv6\u306f\u6697\u9ed9\u306e\u3046\u3061\u306b\u6700\u5927\u91cf\u306e\u30e6\u30fc\u30b6\u7a7a\u9593\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\nfork\u306f\u89aa\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u306e\u8907\u88fd\u306e\u305f\u3081\u306b\u5fc5\u8981\u3068\u306a\u308b\u5b50\u30d7\u30ed\u30bb\u30b9\u306e\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\n\u305d\u3057\u3066exec\u306f\u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u3092\u4fdd\u6301\u3059\u308b\u306e\u306b\u5341\u5206\u306a\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u3002
\n\uff08malloc\u306a\u3069\u3067\uff09\u5b9f\u884c\u4e2d\u306b\u30e1\u30e2\u30ea\u304c\u3055\u3089\u306b\u5fc5\u8981\u306b\u306a\u3063\u305f\u30d7\u30ed\u30bb\u30b9\u306f\u3001\u30c7\u30fc\u30bf\u30e1\u30e2\u30ea\u3092n\u30d0\u30a4\u30c8\u307e\u3067\u5897\u3084\u3059\u305f\u3081\u306bsbrk(n)\u3092\u547c\u3076\u3053\u3068\u304c\u3067\u304d\u308b\u3002
\nsbrk\u306f\u65b0\u3057\u3044\u30e1\u30e2\u30ea\u306e\u5834\u6240\u3092\u8fd4\u3059\u3002<\/p>\n
xv6\u306f\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u306f\u63d0\u4f9b\u3057\u306a\u3044\u306e\u3067\u3001\u30d5\u30a1\u30a4\u30eb\u3084\u30d7\u30ed\u30bb\u30b9\u306b\u30e6\u30fc\u30b6\u3092\u7d50\u3073\u3064\u3051\u3066\u4ed6\u306e\u30e6\u30fc\u30b6\u304b\u3089\u4fdd\u8b77\u3059\u308b\u3068\u3044\u3046\u4e8b\u306f\u51fa\u6765\u306a\u3044\u3002
\nUnix\u7684\u306b\u8a00\u3048\u3070\u3001\u5168\u3066\u306exv6\u306e\u30d7\u30ed\u30bb\u30b9\u306froot\u6a29\u9650\u3067\u5b9f\u884c\u3055\u308c\u308b\u3002<\/p>\n
\u611f\u60f3<\/h3>\n
\u610f\u5916\u3060\u306a\u3068\u601d\u3063\u305f\u306e\u304cexec\u306e\u52d5\u4f5c\u3067\u3059\u3002
\n\u547c\u3073\u51fa\u3057\u5143\u306e\u30e1\u30e2\u30ea\u8aad\u307f\u8fbc\u3093\u3060\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u5b9f\u884c\u30a4\u30e1\u30fc\u30b8\u3067\u201d\u7f6e\u304d\u63db\u3048\u308b\u201d\u30ef\u30b1\u3067\u3059\u306d\u3002
\n\u306a\u306e\u3067\u305d\u306e\u524d\u306bfork\u3057\u3066\u308b\u3068\u3002
\nexec\u3067\u305d\u306e\u307e\u307e\u5225\u306e\u30d7\u30ed\u30bb\u30b9\u3092\u958b\u59cb\u51fa\u6765\u308c\u3070fork\u3059\u308b\u5fc5\u8981\u3082\u306a\u3044\u3068\u601d\u3046\u3093\u3067\u3059\u304c\u3001\u30c6\u30ad\u30b9\u30c8\u306b\u3082fork\u3068exec\u304c\u5206\u304b\u308c\u3066\u308b\u306e\u306b\u306f\u7406\u7531\u304c\u3042\u308b\u3002\u305d\u308c\u306f\u5f8c\u307b\u3069\u4e5e\u3046\u3054\u671f\u5f85\u3068\u66f8\u3044\u3066\u3042\u308b\u306e\u3067\u8ffd\u3005\u5206\u304b\u3063\u3066\u304f\u308b\u306e\u3067\u3057\u3087\u3046\u3002<\/p>\n
\u30bd\u30fc\u30b9\u304c\u3061\u3087\u308d\u3063\u3068\u51fa\u3066\u304d\u307e\u3057\u305f\u3002
\n\u30b7\u30a7\u30eb\u306e\u30bd\u30fc\u30b9\u306e\u4e00\u90e8\u3067\u3059\u3002
\n\u524d\u56de\u3001\u30b7\u30a7\u30eb\u306f\u30e6\u30fc\u30b6\u7a7a\u9593\u3067\u5b9f\u884c\u3055\u308c\u308b\u901a\u5e38\u306e\u30d7\u30ed\u30b0\u30e9\u30e0\u3067\u3042\u308b\u3001\u3068\u66f8\u304b\u308c\u3066\u307e\u3057\u305f\u306e\u3067\u3001\u307e\u3060\u30ab\u30fc\u30cd\u30eb\u90e8\u5206\u3092\u8aad\u307f\u59cb\u3081\u308b\u3068\u3044\u3046\u3068\u3053\u308d\u307e\u3067\u306f\u81f3\u3063\u3066\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
\u3042\u3068\u3001xv6\u306b\u306f\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u304c\u306a\u3044\u3068\u66f8\u304b\u308c\u3066\u3044\u307e\u3059\u3002
\n\u30e6\u30fc\u30b6\u306e\u6982\u5ff5\u304c\u3042\u308b\u3068\u3001\u7ba1\u7406\u3084\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u306e\u305f\u3081\u306b\u8272\u3005\u306a\u6982\u5ff5\u3092\u5c0e\u5165\u305b\u3056\u308b\u3092\u5f97\u305a\u3001\u30bd\u30fc\u30b9\u304c\u8907\u96d1\u3067\u3088\u308a\u7406\u89e3\u3057\u3065\u3089\u3044\u3082\u306e\u306b\u306a\u308b\u306e\u3067\u3057\u3087\u3046\u3002
\n\u305d\u306e\u3078\u3093\u6c17\u306b\u3057\u306a\u304f\u3066\u3044\u3044\u3068\u3044\u3046\u3053\u3068\u306f\u3001\u3068\u308a\u3042\u3048\u305a\u8aad\u3080\u3068\u3044\u3046\u8eab\u306b\u3068\u3063\u3066\u306f\u3042\u308a\u304c\u305f\u3044\u3053\u3068\u3067\u3059\u3002<\/p>\n
sh.c\u306eruncmd\u95a2\u6570\u3092\u898b\u308b\u3068\u3001switch\u306e\u6700\u521d\u306bdefault\u3092\u7f6e\u3044\u3066\u3042\u308a\u307e\u3059\u3002
\ndefault\u3063\u3066\u6700\u521d\u3067\u3082\u3044\u3044\u306e\u304b\u30fc\uff01\u3063\u3066\u306e\u304c\u4eca\u56de\u4e00\u756a\u306e\u9a5a\u304d\u3067\u3059\u3002<\/p>\n
\u307b\u3068\u3093\u3069\u8a33\u3057\u3066\u3057\u307e\u3044\u307e\u3057\u305f\u3002
\n\u305f\u3076\u3093\u4eca\u56de\u306b\u9650\u3089\u305a\u3067\u3059\u304c\u3001\u7ffb\u8a33\u306f\u8d85\u9069\u5f53\u3067\u3059\u306e\u3067\u3054\u6ce8\u610f\u304f\u3060\u3055\u3044\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[405],"class_list":["post-1220","post","type-post","status-publish","format-standard","hentry","category-tech","tag-xv6"],"_links":{"self":[{"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/posts\/1220","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/comments?post=1220"}],"version-history":[{"count":0,"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/posts\/1220\/revisions"}],"wp:attachment":[{"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/media?parent=1220"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/categories?post=1220"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/peta.okechan.net\/blog\/wp-json\/wp\/v2\/tags?post=1220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}