{"id":1940,"date":"2010-11-09T15:40:43","date_gmt":"2010-11-09T07:40:43","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=1940"},"modified":"2010-11-11T18:18:59","modified_gmt":"2010-11-11T10:18:59","slug":"%e8%bf%9b%e7%a8%8b%e7%94%a8%e6%88%b7%e7%a9%ba%e9%97%b4%e7%9a%84%e4%bb%a3%e7%a0%81%e6%8f%8f%e8%bf%b0","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/1940","title":{"rendered":"\u8fdb\u7a0b\u7528\u6237\u7a7a\u95f4\u7684\u4ee3\u7801\u63cf\u8ff0"},"content":{"rendered":"

\u5728\u524d\u6587\u4e2d\uff0c\u6211\u4eec\u5bf9\u8fdb\u7a0b\u7684\u865a\u62df\u5730\u5740\u7a7a\u95f4\u8fdb\u884c\u4e86\u6982\u8ff0\u3002\u672c\u6587\u5c06\u4ece\u5185\u6838\u4ee3\u7801\u7684\u89d2\u5ea6\u6765\u5206\u6790\u8fdb\u7a0b\u7684\u7528\u6237\u7a7a\u95f4\u7684\u7684\u7ec4\u7ec7\u548c\u7ed3\u6784\u3002<\/p>\n

\u4e0a\u6587\u4e2d\u63d0\u5230\uff0c\u6bcf\u4e00\u4e2a\u8fdb\u7a0b\u90fd\u62e5\u67093GB\u5927\u5c0f\u7684\u7528\u6237\u7a7a\u95f4\uff0c\u800c\u8fde\u7eed\u7528\u6237\u7a7a\u95f4\u53c8\u6309\u7167\u5b58\u50a8\u5185\u5bb9\u7684\u4e0d\u540c\u88ab\u5212\u5206\u6210\u82e5\u5e72\u4e2a\u533a\u57df\u3002\u5728\u5185\u6838\u4e2d\uff0c\u4e3b\u8981\u901a\u8fc7mm_struct\u7ed3\u6784\u4f53\u548cvm_area_struct\u7ed3\u6784\u4f53\u5bf9\u8fdb\u7a0b\u7528\u6237\u7a7a\u95f4\u8fdb\u884c\u63cf\u8ff0\u3002\u524d\u8005\u662f\u5bf9\u8fdb\u7a0b\u7684\u7528\u6237\u7a7a\u95f4\u8fdb\u884c\u6574\u4f53\u7684\u63cf\u8ff0\uff1b\u800c\u540e\u8005\u5219\u662f\u5bf9\u7528\u6237\u7a7a\u95f4\u4e2d\u7684\u67d0\u4e2a\u533a\u57df\u8fdb\u884c\u63cf\u8ff0\u3002\u663e\u7136\uff0c\u6bcf\u4e00\u4e2a\u8fdb\u7a0b\u5bf9\u5e94\u7684\u6709\u4e00\u4e2amm_struct\u7ed3\u6784\u548c\u591a\u4e2avm_area_struct\u7ed3\u6784\u3002<\/p>\n

1.mm_struct\u7ed3\u6784<\/p>\n

\u6700\u65b0\u7248\u672c\u4e2d\u7684mm_struct\u7ed3\u6784\u5b57\u6bb5\u6bd4\u8f83\u591a\uff0c\u63a5\u4e0b\u6765\u53ea\u5bf9\u90e8\u5206\u5b57\u6bb5\u505a\u4ee5\u8bf4\u660e\u3002<\/p>\n

mmap<\/strong>\uff1avm_area_struct\u7ed3\u6784\u4f53\u7c7b\u578b\u7684\u6307\u9488\u3002\u6307\u5411\u8fdb\u7a0b\u7528\u6237\u7a7a\u95f4\u4e2d\u5404\u533a\u57df\u6240\u7ec4\u6210\u7684\u53cc\u94fe\u8868\u3002\u94fe\u8868\u65b9\u5f0f\u53ef\u4ee5\u9ad8\u6548\u7684\u904d\u5386\u6240\u6709\u5143\u7d20\uff1b
\n mm_rb<\/strong>\uff1arb_root\u7ed3\u6784\u4f53\u7c7b\u578b\u3002\u540c\u6837\u63cf\u8ff0\u5185\u5b58\u533a\u57df\u5757\uff0c\u53ea\u4e0d\u8fc7\u91c7\u7528\u7ea2\u9ed1\u6811\u6765\u8868\u793a\u3002\u7528\u7ea2\u9ed1\u6811\u53ef\u4ee5\u5feb\u901f\u7d22\u5f15\u5230\u6307\u5b9a\u7684\u5143\u7d20\uff1b
\n mm_users<\/strong>\uff1aatomic_t\u7c7b\u578b\u3002\u7528\u6765\u8bb0\u5f55\u6b63\u5728\u4f7f\u7528\u8be5\u5730\u5740\u7a7a\u95f4\u7684\u8fdb\u7a0b\u6570\u76ee\u3002\u6bd4\u5982\uff0c\u5f53\u524d\u67093\u4e2a\u8fdb\u7a0b\u6b63\u5728\u5171\u4eab\u8be5\u5730\u5740\u7a7a\u95f4\uff0c\u90a3\u4e48\u5176\u503c\u4e3a3\uff1b
\n mm_count<\/strong>\uff1aatomic_t\u7c7b\u578b\u3002\u8bb0\u5f55mm_struct\u7ed3\u6784\u4f53\u88ab\u5f15\u7528\u7684\u6b21\u6570\u3002\u5982\u679c\u5f53\u524d\u8be5\u5730\u5740\u7a7a\u95f4\u53ea\u88ab\u4e24\u4e2a\u8fdb\u7a0b\u6240\u5171\u4eab\uff0c\u90a3\u4e48\u8be5\u503c\u4e3a1\uff0cmm_users\u4e3a2\uff1b\u5f53\u8fd9\u4e24\u4e2a\u8fdb\u7a0b\u90fd\u9000\u51fa\u65f6\uff0c\u8be5\u503c\u4e3a0\uff0cmm_users\u4e5f\u4e3a0\u3002\u53e6\u5916\uff0c\u5185\u6838\u7ebf\u7a0b\u5e76\u4e0d\u9700\u8981\u8bbf\u95ee\u7528\u6237\u7684\u5185\u5b58\u7a7a\u95f4\uff0c\u4e5f\u5e76\u4e0d\u9700\u8981\u521b\u5efa\u9875\u8868\u3002\u5185\u6838\u7ebf\u7a0b\u4e00\u822c\u4f1a\u76f4\u63a5\u4f7f\u7528\u524d\u4e00\u4e2a\u8fdb\u7a0b\u7684mm_struct\u7ed3\u6784\u3002\u56e0\u6b64\u8be5\u5b57\u6bb5\u7684\u8ba1\u6570\u8fd8\u5305\u62ec\u5185\u6838\u7ebf\u7a0b\u5bf9\u8fd9\u4e2a\u7ed3\u6784\u7684\u5f15\u7528\u3002
\n map_count<\/strong>\uff1aint\u7c7b\u578b\u3002\u5185\u5b58\u533a\u57df\u7684\u4e2a\u6570\uff1b
\n pgd<\/strong>\uff1apgd_t\u7c7b\u578b\uff0c\u8be5\u7ed3\u6784\u4f53\u7c7b\u578b\u5185\u90e8\u5c01\u88c5\u7684\u662funsigned long\u7c7b\u578b\u7684\u6570\u636e\u3002pgd\u8868\u793a\u7684\u662f\u9875\u76ee\u5f55\u57fa\u5740\u3002\u5f53\u8c03\u5ea6\u7a0b\u5e8f\u8c03\u5ea6\u4e00\u4e2a\u8fdb\u7a0b\u8fd0\u884c\u65f6\uff0c\u5c31\u5c06\u8fd9\u4e2a\u7ebf\u6027\u5730\u5740\u8f6c\u5316\u4e3a\u7269\u7406\u5730\u5740\uff0c\u5e76\u5199\u5165CR3\u63a7\u5236\u5bc4\u5b58\u5668\u4e2d\uff1b
\n start_code, end_code, start_data, end_data<\/strong>\uff1aunsigned long\u7c7b\u578b\u3002\u8fdb\u7a0b\u4ee3\u7801\u6bb5\u548c\u6570\u636e\u6bb5\u7684\u8d77\u59cb\u5730\u5740\u548c\u7ec8\u6b62\u5730\u5740\uff1b
\n start_brk, brk, start_stack<\/strong>\uff1aunsigned long\u7c7b\u578b\u3002\u5206\u522b\u4e3a\u5806\u7684\u8d77\u59cb\u5730\u5740\u548c\u7ec8\u6b62\u5730\u5740\uff0c\u5806\u6808\u7684\u8d77\u59cb\u5730\u5740\u3002\u4e0a\u6587\u8bf4\u8fc7\uff0c\u8fdb\u7a0b\u7684\u5806\u6808\u6bb5\u662f\u6839\u636e\u9700\u6c42\u5411\u4e0b\uff08\u671d\u4f4e\u5730\u5740\u65b9\u5411\uff09\u5ef6\u4f38\u7684\uff0c\u56e0\u6b64\u8fd9\u91cc\u5e76\u6ca1\u6709\u5806\u6808\u6bb5\u7684\u7ec8\u6b62\u5730\u5740\uff1b
\n arg_start, arg_end, env_start, env_end<\/strong>\uff1aunsigned long\u7c7b\u578b\u3002\u547d\u4ee4\u884c\u53c2\u6570\u6240\u5728\u5185\u5b58\u7684\u8d77\u59cb\u5730\u5740\u548c\u7ec8\u6b62\u5730\u5740\uff0c\u73af\u5883\u53d8\u91cf\u6240\u5728\u5185\u5b58\u7684\u8d77\u59cb\u5730\u5740\u548c\u7ec8\u6b62\u5730\u5740\uff1b<\/p>\n

2.vm_area_struct\u7ed3\u6784<\/p>\n

\u4e0a\u9762\u6211\u4eec\u5df2\u7ecf\u77e5\u9053\uff0c\u8be5\u7ed3\u6784\u4f53\u63cf\u8ff0\u7684\u662f\u8fdb\u7a0b\u7528\u6237\u7a7a\u95f4\u4e2d\u7684\u4e00\u4e2a\u865a\u62df\u5185\u5b58\u533a\u95f4\uff08Virtual Memory Area\uff0cVMA\uff09\u3002
\n vm_mm<\/strong>\uff1amm_struct\u7ed3\u6784\u4f53\u7c7b\u578b\u6307\u9488\u3002\u6307\u5411\u8be5\u533a\u57df\u6240\u5c5e\u7684\u7528\u6237\u7a7a\u95f4\u5bf9\u5e94\u7684mm_struct\u7ed3\u6784\u4f53\u3002
\n vm_start\uff0cvm_end<\/strong>\uff1aunsigned long\u7c7b\u578b\u3002\u8be5\u865a\u5b58\u533a\u57df\u7684\u8d77\u59cb\u5730\u5740\u548c\u7ec8\u6b62\u5730\u5740\u3002
\n vm_next\uff0cvm_prev<\/strong>\uff1avm_area_struct\u7ed3\u6784\u4f53\u7c7b\u578b\u6307\u9488\u3002\u6784\u6210VMA\u53cc\u8054\u8868\u3002
\n vm_flags<\/strong>\uff1aunsigned long\u7c7b\u578b\u3002\u8be5\u865a\u5b58\u533a\u7684\u6807\u5fd7\u3002
\n vm_page_prot<\/strong>\uff1apgprot_t\u7ed3\u6784\u4f53\u7c7b\u578b\uff0c\u5185\u90e8\u5c01\u88c5\u4e86unsigned long\u7c7b\u578b\u3002\u8bbf\u95ee\u63a7\u5236\u6743\u9650\u3002
\n vm_ops<\/strong>\uff1avm_operations_struct\u7ed3\u6784\u4f53\u7c7b\u578b\u3002\u8be5\u865a\u5b58\u533a\u57df\u7684\u64cd\u4f5c\u51fd\u6570\u63a5\u53e3\uff0c\u8fd9\u4e9b\u51fd\u6570\u53ef\u4ee5\u5bf9\u865a\u5b58\u533a\u4e2d\u7684\u9875\u8fdb\u884c\u64cd\u4f5c\u3002<\/p>\n

3.\u6570\u636e\u7ed3\u6784\u7684\u5173\u7cfb<\/p>\n

\u4e86\u89e3\u4e86\u4e0a\u8ff0\u7ed3\u6784\u4f53\u7684\u5173\u952e\u5b57\u6bb5\uff0c\u5b83\u4eec\u4e0e\u8fdb\u7a0b\u4e4b\u95f4\u7684\u903b\u8f91\u5173\u7cfb\u4fbf\u662f\u6211\u4eec\u63a5\u4e0b\u6765\u8981\u5173\u5fc3\u7684\u91cd\u70b9\u3002\u6211\u4eec\u77e5\u9053\uff0c\u4e00\u4e2a\u8fdb\u7a0b\u5728\u5185\u6838\u4e2d\u4f7f\u7528task_struct\u7ed3\u6784\u5bf9\u5176\u8fdb\u884c\u63cf\u8ff0\u3002task_struct\u7ed3\u6784\u4e2d\u6709\u4e00\u4e2amm\u5b57\u6bb5\uff0c\u5b83\u6240\u6307\u5411\u7684\u4fbf\u662f\u4e0e\u8be5\u8fdb\u7a0b\u7528\u6237\u7a7a\u95f4\u6240\u5bf9\u5e94\u7684mm_struct\u7ed3\u6784\u4f53\u3002\u901a\u8fc7\u4e0a\u8ff0\u5206\u6790\uff0c\u6211\u4eec\u77e5\u9053mm_struct\u7ed3\u6784\u4e2d\u6709mmap\u5b57\u6bb5\uff0c\u5b83\u6307\u5411VMA\u53cc\u94fe\u8868\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u4f7f\u7528current->mm->mmap\u5c31\u53ef\u4ee5\u83b7\u5f97VMA\u94fe\u8868\u7684\u5934\u6307\u9488\u3002\u90a3\u4e48current->mm->mmap->vm->next\u5c31\u53ef\u4ee5\u83b7\u5f97\u6307\u5411\u8be5VMA\u53cc\u8054\u8868\u7684\u4e0b\u4e00\u4e2a\u7ed3\u70b9\u7684\u6307\u9488\u3002<\/p>\n

4.\u52a8\u624b\u67e5\u770b\u5185\u5b58\u533a\u57df<\/p>\n

\u4e0a\u8ff0\u6211\u4eec\u4ece\u4ee3\u7801\u89d2\u5ea6\u5206\u6790\u4e86\u7528\u6237\u5730\u5740\u7a7a\u95f4\u548c\u5185\u5b58\u533a\u57df\u3002\u90a3\u4e48\u5bf9\u4e8e\u4e00\u4e2a\u4efb\u610f\u7684\u8fdb\u7a0b\uff0c\u6211\u4eec\u5982\u4f55\u67e5\u770b\u5b83\u7684\u5185\u5b58\u7a7a\u95f4\u548c\u6240\u5212\u5206\u7684\u5185\u5b58\u533a\u57df\uff1f<\/p>\n

\u6211\u4eec\u5148\u770b\u4e00\u4e2a\u7b80\u5355\u7684\u6d4b\u8bd5\u7a0b\u5e8f\uff1a<\/p>\n

#include \r\n#include \r\n\r\nint main()\r\n{\r\n\tint i=1;\r\n\tchar *str=NULL;\r\n\tprintf(\"hello,world!\\n\");\r\n\tstr=(char *)malloc(sizeof(char)*1119);\r\n\r\n\tsleep(1000);\r\n\r\n\treturn 0;\r\n}<\/pre>\n
\u8fd9\u4e2a\u7a0b\u5e8f\u4e2d\u4f7f\u7528\u5230\u4e86malloc\u51fd\u6570\uff0c\u56e0\u6b64str\u53d8\u91cf\u5b58\u50a8\u4e8e\u5806\u4e2d\u3002\u6211\u4eec\u901a\u8fc7\u6253\u5370\/proc\/3530\/maps\u6587\u4ef6\uff0c\u5373\u53ef\u770b\u5230\u8be5\u8fdb\u7a0b\u7684\u5185\u5b58\u7a7a\u95f4\u5212\u5206\u3002\u5176\u4e2d3530\u662f\u8be5\u8fdb\u7a0b\u7684id\u3002<\/p>\n
edsionte@edsionte-desktop:~$ cat \/proc\/3530\/maps\r\n0014a000-00165000 r-xp 00000000 08:07 398276     \/lib\/ld-2.11.1.so\r\n00165000-00166000 r--p 0001a000 08:07 398276     \/lib\/ld-2.11.1.so\r\n00166000-00167000 rw-p 0001b000 08:07 398276     \/lib\/ld-2.11.1.so\r\n001d8000-0032b000 r-xp 00000000 08:07 421931     \/lib\/tls\/i686\/cmov\/libc-2.11.1.so\r\n0032b000-0032c000 ---p 00153000 08:07 421931     \/lib\/tls\/i686\/cmov\/libc-2.11.1.so\r\n0032c000-0032e000 r--p 00153000 08:07 421931     \/lib\/tls\/i686\/cmov\/libc-2.11.1.so\r\n0032e000-0032f000 rw-p 00155000 08:07 421931     \/lib\/tls\/i686\/cmov\/libc-2.11.1.so\r\n0032f000-00332000 rw-p 00000000 00:00 0\r\n00441000-00442000 r-xp 00000000 00:00 0          [vdso]\r\n08048000-08049000 r-xp 00000000 08:09 326401     \/home\/edsionte\/test\r\n08049000-0804a000 r--p 00000000 08:09 326401     \/home\/edsionte\/test\r\n0804a000-0804b000 rw-p 00001000 08:09 326401     \/home\/edsionte\/test\r\n08958000-08979000 rw-p 00000000 00:00 0          [heap]\r\nb78ce000-b78cf000 rw-p 00000000 00:00 0\r\nb78dd000-b78e0000 rw-p 00000000 00:00 0\r\nbfa6a000-bfa7f000 rw-p 00000000 00:00 0          [stack]<\/pre>\n
\u6bcf\u4e00\u884c\u4fe1\u606f\u4f9d\u6b21\u663e\u793a\u7684\u5185\u5bb9\u4e3a\u5185\u5b58\u533a\u57df\u5176\u5b9e\u5730\u5740-\u7ec8\u6b62\u5730\u5740\uff0c\u8bbf\u95ee\u6743\u9650\uff0c\u504f\u79fb\u91cf\uff0c\u4e3b\u8bbe\u5907\u53f7\uff1a\u6b21\u8bbe\u5907\u53f7\uff0cinode\uff0c\u6587\u4ef6\u3002<\/p>\n
\u4e0a\u9762\u7684\u4fe1\u606f\u4e0d\u4f46\u5305\u542b\u4e86test\u53ef\u6267\u884c\u5bf9\u8c61\u7684\u5404\u5185\u5b58\u533a\u57df\uff0c\u800c\u4e14\u8fd8\u5206\u522b\u663e\u793a\u4e86 \/lib\/ld-2.11.1.so\uff08\u52a8\u6001\u8fde\u63a5\u7a0b\u5e8f\uff09\u6587\u4ef6\u548c\/lib\/tls\/i686\/cmov\/libc-2.11.1.so\uff08C\u5e93\uff09\u6587\u4ef6\u7684\u5185\u5b58\u533a\u57df\u4fe1\u606f\u3002<\/p>\n
\u6211\u4eec\u4ece\u67d0\u4e2a\u5185\u5b58\u533a\u57df\u7684\u8bbf\u95ee\u6743\u9650\u4e0a\u53ef\u4ee5\u5927\u81f4\u5224\u65ad\u8be5\u533a\u57df\u7684\u7c7b\u578b\u3002\u5404\u4e2a\u5c5e\u6027\u7b26\u53f7\u7684\u610f\u4e49\u4e3a\uff1ar-read\uff0cw-write\uff0cx-execute\uff0cs-shared\uff0cp-private\u3002\u56e0\u6b64\uff0cr-x\u4e00\u822c\u4ee3\u8868\u7a0b\u5e8f\u7684\u4ee3\u7801\u6bb5\uff0c\u5373\u53ef\u8bfb\uff0c\u53ef\u6267\u884c\u3002rw-\u53ef\u80fd\u4ee3\u8868\u6570\u636e\u6bb5\uff0cBSS\u6bb5\u548c\u5806\u6808\u6bb5\u7b49\uff0c\u5373\u53ef\u8bfb\uff0c\u53ef\u5199\u3002\u5806\u6808\u6bb5\u4ece\u884c\u4fe1\u606f\u7684\u6587\u4ef6\u540d\u5c31\u53ef\u4ee5\u533a\u5206\uff1b\u5982\u679c\u67d0\u884c\u4fe1\u606f\u7684\u6587\u4ef6\u540d\u4e3a\u7a7a\uff0c\u90a3\u4e48\u53ef\u80fd\u662fBSS\u6bb5\u3002\u53e6\u5916\uff0c\u4e0a\u8ff0test\u8fdb\u7a0b\u5171\u4eab\u4e86\u5185\u6838\u52a8\u6001\u5e93\uff0c\u6240\u4ee5\u572800441000-00442000\u884c\u5904\u6587\u4ef6\u540d\u663e\u793a\u4e3avdso\uff08Virtual Dynamic Shared Object\uff09\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
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