{"id":8120,"date":"2023-12-19T11:54:29","date_gmt":"2023-12-19T03:54:29","guid":{"rendered":"https:\/\/yanjingang.com\/blog\/?p=8120"},"modified":"2023-12-29T12:03:34","modified_gmt":"2023-12-29T04:03:34","slug":"ebpf-%e4%bd%bf%e7%94%a8offset%e6%8e%a2%e6%b5%8b%e7%94%a8%e6%88%b7%e7%a8%8b%e5%ba%8f%e5%87%bd%e6%95%b0%e8%b0%83%e7%94%a8","status":"publish","type":"post","link":"https:\/\/yanjingang.com\/blog\/?p=8120","title":{"rendered":"eBPF\u2014\u4f7f\u7528\u7b26\u53f7\u8868offset\u63a2\u6d4b\u51fd\u6570\u8c03\u7528"},"content":{"rendered":"

\u4e0a\u4e00\u6b21\uff0c\u6211\u4eec\u901a\u8fc7uprobe\u5b9e\u73b0\u4e00\u4e2a\u5bf9\u7528\u6237\u7a7a\u95f4\u81ea\u5b9a\u4e49\u7a0b\u5e8f\u7684\u7279\u5b9a\u51fd\u6570\u51fa\u5165\u53e3\u8fdb\u884c\u4ee3\u7801\u6ce8\u5165\u548c\u63a2\u6d4b\u7684\u65b9\u6cd5\uff0c\u4f46\u5b83\u8fd8\u6709\u5f88\u591a\u4e0d\u5b8c\u5584\u7684\u5730\u65b9\uff0c\u6bd4\u5982\u9700\u8981\u63d0\u524d\u51c6\u5907\u597d\u7f16\u8bd1\u540e\u7684\u51fd\u6570\u7b26\u53f7\uff0c\u540c\u65f6\u751f\u4ea7\u73af\u5883\u4ea7\u51fa\u901a\u5e38\u4e5f\u4e0d\u5e26\u7b26\u53f7\u3001\u4ea7\u51fa\u7684\u90e8\u7f72\u4f4d\u7f6e\u901a\u5e38\u4e5f\u4e0d\u56fa\u5b9a\uff0c\u7ed9\u6211\u4eec\u5728\u5b9e\u9645\u573a\u666f\u4e2d\u4f7f\u7528\u5e26\u6765\u4e0d\u4fbf\u3002\u672c\u6587\u5c31\u8bb2\u89e3\u4e0b\u5982\u4f55\u901a\u8fc7\u5bfc\u51fa\u7b26\u53f7\u8868\u3001\u4ea7\u51fa\u53bb\u7b26\u53f7\uff0c\u901a\u8fc7\u7b26\u53f7\u8868\u7684offset\u3001\u7c7b\u51fd\u6570\u540d\u3001\u8fdb\u7a0bPID\u6765\u8fdb\u884c\u7528\u6237\u81ea\u5b9a\u4e49\u51fd\u6570\u8c03\u7528\u7684\u63a2\u6d4b\uff0c\u4ece\u800c\u66f4\u65b9\u4fbf\u76f4\u63a5\u5728\u751f\u4ea7\u73af\u5883\u4f7f\u7528\u3002<\/p>\n

\u4e00\u3001\u6982\u8ff0<\/h1>\n

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

1.\u7b26\u53f7<\/h4>\n

\u7b26\u53f7\uff08Symbol\uff09\u5e38\u7528\u6765\u8868\u793a\u4e00\u4e2a\u5730\u5740\uff0c\u8fd9\u4e2a\u5730\u5740\u53ef\u80fd\u662f\u4e00\u7aef\u7a0b\u5e8f\u7684\u8d77\u59cb\u5730\u5740\uff0c\u4e5f\u53ef\u80fd\u662f\u4e00\u4e2a\u53d8\u91cf\u7684\u8d77\u59cb\u5730\u5740\uff0c\u7b80\u800c\u8a00\u4e4b\uff0c\u5c06\u5b83\u5f53\u505a\u662f\u6807\u8bb0\u6216\u540d\u79f0\u5373\u53ef\u3002
\n\u7f16\u8bd1\u94fe\u63a5\u7684\u8fc7\u7a0b\uff0c\u5b9e\u8d28\u4e0a\u5c31\u662f\u5c06\u4e0d\u540c\u7684\u76ee\u6807\u6587\u4ef6\u6c47\u96c6\u5728\u4e00\u8d77\u3002\u94fe\u63a5\u6784\u6210\u4e2d\uff0c\u76ee\u6807\u6587\u4ef6\u7684\u76f8\u4e92\u62fc\u5408\u6c47\u96c6\uff0c\u5b9e\u9645\u4e0a\u662f\u76ee\u6807\u6587\u4ef6\u4e4b\u95f4\u5bf9\u5730\u5740\u7684\u5f15\u7528\u3002\u94fe\u63a5\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u5c06\u51fd\u6570\u548c\u53d8\u91cf\u7edf\u4e00\u79f0\u4f5c\u4e3a\u7b26\u53f7 \uff0c\u51fd\u6570\u540d\u4e0e\u53d8\u91cf\u540d\u79f0\u5c31\u662f\u7b26\u53f7\u540d \uff0c\u5176\u8bb0\u5f55\u7684\u5730\u5740\u4fe1\u606f\u5c31\u662f\u5176\u7b26\u53f7\u503c \u3002<\/p>\n

2.\u7b26\u53f7\u8868<\/h4>\n

\u94fe\u63a5\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u9700\u8981\u5bf9\u5404\u79cd\u7b26\u53f7\u8fdb\u884c\u7ba1\u7406\uff0c\u6bcf\u4e00\u4e2a\u76ee\u6807\u6587\u4ef6\u90fd\u4f1a\u6709\u4e00\u4e2a\u5bf9\u5e94\u7684\u7b26\u53f7\u8868 Symbol Table \uff0c\u7528\u6765\u8bb0\u5f55\u76ee\u6807\u6587\u4ef6\u4e2d\u6240\u6709\u7528\u5230\u7684\u7b26\u53f7\uff0c\u5728\u9759\u6001\u94fe\u63a5\u65f6\u5019\uff0c\u4f1a\u8fdb\u884c\u76f8\u540c\u6027\u8d28\u6bb5\u7684\u5408\u5e76\u3002<\/p>\n

\u7b26\u53f7\u8868\u5206\u7c7b\uff1a<\/p>\n

    \n
  • Symbol Table\uff1a \u6240\u6709\u7b26\u53f7\u8868\n
      \n
    • \u5b58\u50a8\u6240\u6709\u7684\u7b26\u53f7\u4fe1\u606f\uff0c\u5305\u542b\u52a8\u6001\u94fe\u63a5\u7b26\u53f7\u8868\u5185\u7684\u7b26\u53f7<\/li>\n<\/ul>\n<\/li>\n
    • Dynamic Symbol Table\uff1a\u52a8\u6001\u94fe\u63a5\u7b26\u53f7\u8868\uff0c\u95f4\u63a5\u7b26\u53f7\u8868\uff08Indirect Symbol\uff09\n
        \n
      • \u5b58\u50a8\u7740\u6240\u6709\u4f7f\u7528\u5230\u7684\u4f4d\u4e8e\u5176\u4ed6\u5916\u90e8\u52a8\u6001\u5e93\u4e2d\u7684\u7b26\u53f7\u4fe1\u606f\uff0c\u52a8\u6001\u94fe\u63a5\u65f6\u8fdb\u884c\u7ed1\u5b9a<\/li>\n<\/ul>\n<\/li>\n
      • String Table\uff1a\u7b26\u53f7\u7684\u540d\u79f0<\/li>\n<\/ul>\n

        \u8bfb\u53d6\u7b26\u53f7\u8868\u7684\u65b9\u6cd5\uff1a<\/p>\n

        $ readelf -s build\/utest\r\n\r\nSymbol table '.dynsym' contains 27 entries:\r\n   Num:    Value          Size Type    Bind   Vis      Ndx Name\r\n     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND \r\n     1: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZSt4endlIcSt11char_trait@GLIBCXX_3.4 (3)\r\n     2: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND sleep@GLIBC_2.2.5 (2)\r\n     3: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND __cxa_atexit@GLIBC_2.2.5 (2)\r\n     4: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZStlsISt11char_traitsIcE@GLIBCXX_3.4 (3)\r\n     5: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZNSolsEPFRSoS_E@GLIBCXX_3.4 (3)\r\n     6: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZNSt8ios_base4InitC1Ev@GLIBCXX_3.4 (3)\r\n     7: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZNSolsEi@GLIBCXX_3.4 (3)\r\n     8: 0000000000000000     0 NOTYPE  WEAK   DEFAULT  UND _ITM_deregisterTMCloneTab\r\n     9: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND __libc_start_main@GLIBC_2.2.5 (2)\r\n    10: 0000000000000000     0 NOTYPE  WEAK   DEFAULT  UND __gmon_start__\r\n    11: 0000000000000000     0 NOTYPE  WEAK   DEFAULT  UND _ITM_registerTMCloneTable\r\n    12: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND _ZNSt8ios_base4InitD1Ev@GLIBCXX_3.4 (3)\r\n    13: 0000000000004010     0 NOTYPE  GLOBAL DEFAULT   25 _edata\r\n    14: 00000000000011e9<\/span>    24 FUNC    GLOBAL DEFAULT   16 _Z9utest_addii<\/span>\r\n    15: 0000000000000000     0 FUNC    WEAK   DEFAULT  UND __cxa_finalize@GLIBC_2.2.5 (2)\r\n    16: 0000000000001201<\/span>    22 FUNC    GLOBAL DEFAULT   16 _Z9utest_subii<\/span>\r\n    17: 0000000000004000     0 NOTYPE  GLOBAL DEFAULT   25 __data_start\r\n    18: 0000000000004158     0 NOTYPE  GLOBAL DEFAULT   26 _end\r\n    19: 0000000000004000     0 NOTYPE  WEAK   DEFAULT   25 data_start\r\n    20: 0000000000002000     4 OBJECT  GLOBAL DEFAULT   18 _IO_stdin_used\r\n    21: 0000000000001217   134 FUNC    GLOBAL DEFAULT   16 main\r\n    22: 0000000000001100    47 FUNC    GLOBAL DEFAULT   16 _start\r\n    23: 0000000000004010     0 NOTYPE  GLOBAL DEFAULT   26 __bss_start\r\n    24: 0000000000001310   101 FUNC    GLOBAL DEFAULT   16 __libc_csu_init\r\n    25: 0000000000004040   272 OBJECT  GLOBAL DEFAULT   26 _ZSt4cout@GLIBCXX_3.4 (3)\r\n    26: 0000000000001380     5 FUNC    GLOBAL DEFAULT   16 __libc_csu_fini\r\n\r\nSymbol table '.symtab' contains 84 entries:\r\n   Num:    Value          Size Type    Bind   Vis      Ndx Name\r\n     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND \r\n     1: 0000000000000318     0 SECTION LOCAL  DEFAULT    1 \r\n     ...\r\n    59: 00000000000011e9    24 FUNC    GLOBAL DEFAULT   16 _Z9utest_addii\r\n    63: 0000000000001217   134 FUNC    GLOBAL DEFAULT   16 main\r\n    66: 0000000000001201    22 FUNC    GLOBAL DEFAULT   16 _Z9utest_subii\r\n    ...<\/code><\/pre>\n
         <\/p>\n
        \u4e8c\u3001\u7b26\u53f7\u8868\u5bfc\u51fa<\/h1>\n
        1.\u5b58\u50a8\u7b26\u53f7\u8868\u7684map<\/h4>\n
        vim symbol.proto\r\n\r\nsyntax = \"proto3\";\r\n\r\nmessage Symbol {\r\n    map<string, uint64> symbols = 1;\r\n};<\/code><\/pre>\n
        2.\u5bfc\u51fa\u7b26\u53f7\u8868\u7a0b\u5e8f<\/h4>\n
        \u5bfc\u51fa\u81ea\u5b9a\u4e49\u7a0b\u5e8f\u7684\u7b26\u53f7\u8868\uff0cmap\u7684key\u4f7f\u7528\u51fd\u6570\u540d\uff08\u5e26\u53c2\u6570\uff09\uff0c\u5b9e\u73b0\u65b9\u6cd5\u8f83\u591a\uff0c\u8fd9\u91cc\u4e0d\u518d\u8d58\u8ff0\u3002<\/p>\n
        3.\u7f16\u8bd1&\u5bfc\u51fa<\/h4>\n
        \u589e\u52a0proto\u7f16\u8bd1\u914d\u7f6e\uff1a<\/p>\n
        cmake_minimum_required(VERSION 3.16)\r\n\r\n# proto\r\nfind_package(Protobuf REQUIRED)\r\nFILE(GLOB protofiles \"${CMAKE_CURRENT_SOURCE_DIR}\/*.proto\")\r\nprotobuf_generate_cpp(PROTO_SRCS PROTO_HDRS ${protofiles})\r\nprotobuf_generate_python(PY_SOURCES ${protofiles})\r\n\r\nadd_library(symbol_proto STATIC ${PROTO_SRCS} ${PROTO_HDRS})\r\ntarget_link_libraries(symbol_proto ${PROTOBUF_LIBRARIES})<\/code><\/pre>\n
        \u4fee\u6539ebpf\u7a0b\u5e8f\u7684cmake\u7f16\u8bd1\u914d\u7f6e\uff1a<\/p>\n
        cmake_minimum_required(VERSION 3.16)\r\nproject(ebpf_test)\r\n\r\n# 1.symbol proto\r\nadd_subdirectory(proto)\r\n\r\n\r\n# 2.user space test app\r\nset(CMAKE_CXX_FLAGS \"${CMAKE_CXX_FLAGS} -Werror -ggdb -rdynamic\")   # debug\r\n# .h\r\ninclude_directories(\r\n    .\/\r\n    \/usr\/include\r\n    \/usr\/local\/include\r\n    ${PROTOBUF_INCLUDE_DIRS}\r\n    ${CMAKE_CURRENT_BINARY_DIR}\r\n)\r\n# utest exec\r\nadd_executable(utest utest\/utest.cc)\r\n# usymbol exec\r\nadd_executable(usymbol utest\/usymbol.cc)\r\ntarget_link_libraries(usymbol protobuf elf symbol_proto)\r\n\r\n\r\n# 3. ebpf\r\n...<\/code><\/pre>\n
        \u7f16\u8bd1\u5e76\u5bfc\u51fa\u7b26\u53f7\uff1a<\/p>\n
        # build\r\nmkdir build && cd build\r\ncmake ..\r\nmake\r\n\r\n# check symbol\r\nobjdump -T utest |grep utest_add\r\n    00000000000011e9 g DF .text 0000000000000018 Base _Z9utest_addii<\/span>\r\nobjdump -T utest |grep utest_sub\r\n    0000000000001201 g DF .text 0000000000000016 Base _Z9utest_subii<\/span>\r\n# dump\r\n.\/usymbol utest > symbols.txt\r\n\r\ncat symbols.txt \r\n  1130 : deregister_tm_clones\r\n  1201 : utest_sub(int, int)<\/span>\r\n  1380 : __libc_csu_fini\r\n  1388 : _fini\r\n  1217 : main\r\n  1310 : __libc_csu_init\r\n  11a0 : __do_global_dtors_aux\r\n  1000 : _init\r\n  11e0 : frame_dummy\r\n  1160 : register_tm_clones\r\n  1100 : _start\r\n  11e9 : utest_add(int, int)<\/span>\r\n  129d : __static_initialization_and_destruction_0(int, int)\r\n\r\n# dump proto map serialize file\r\ncat symbols.dump<\/code><\/pre>\n
        \u8fd9\u91cc\u53ef\u4ee5\u770b\u5230\u5bfc\u51fa\u7684\u7b26\u53f7\u8868\u6587\u4ef6\u91cc\uff0c\u6e05\u7406\u4e86\u4e4b\u524d_Z9<\/span>utest_addii<\/span>\u7684\u524d\u7f00\u548c\u540e\u7f00\uff0c\u5176\u4e2d_Z\u8868\u793a\u662f\u7528\u6237\u51fd\u6570\u6216\u5168\u5c40\u53d8\u91cf\u7b26\u53f7\uff0c9\u8868\u793a\u51fd\u6570\/\u53d8\u91cf\u540d\u7684\u957f\u5ea6\uff0c\u672b\u5c3e\u7684ii\u8868\u793a\u67092\u4e2a\u53c2\u6570\uff0c\u90fd\u662fint\u7c7b\u578b\u3002\u524d\u8fb9\u4fdd\u7559\u76841201\u300111e9\u5373\u4e3a\u7b26\u53f7\u7684offset\u504f\u79fb\u91cf\u3002<\/p>\n
        \u4e09\u3001\u4f7f\u7528offset\u548c\u51fd\u6570\u540d\u76f4\u63a5\u63a2\u6d4b<\/h1>\n
        1.\u4f7f\u7528offset\u63a2\u6d4b<\/h4>\n
        \u6211\u4eec\u5728\u4e0a\u6b21\u7528\u6237\u81ea\u5b9a\u4e49\u7a0b\u5e8f\u63a2\u6d4b\u7684\u57fa\u7840\u4e0a\u8fdb\u884c\u4fee\u6539\uff0c\u589e\u52a0\u7b26\u53f7\u8868\u52a0\u8f7d\u3001\u6839\u636e\u51fd\u6570\u540d\u83b7\u53d6offset\uff1a<\/p>\n
        vim uprobe_symbol.cc\r\n\r\n...\r\n#include \"proto\/symbol.pb.h\"\r\n\r\nint main(int argc, char **argv)\r\n{\r\n    ...\r\n\r\n    \/\/ \u52a0\u8f7dsymbols.dump\u6587\u4ef6\r\n    std::ifstream is(\".\/symbols.dump\", std::ios::binary);\r\n    auto symbol = new Symbol();\r\n    symbol->ParseFromIstream(&is);\r\n    is.close();\r\n    auto symbolMap = symbol->symbols();\r\n    \r\n    \/\/ \u83b7\u53d6\u51fd\u6570\u5bf9\u5e94\u7b26\u53f7\u8868\u7684offset\r\n    std::string func_name = \"utest_add(int, int)<\/span>\";\r\n    uint64_t func_offset = 0;\r\n    func_offset<\/span> = symbolMap[func_name];\r\n    std::cout << \"func_offset:\" << func_offset << std::endl;\r\n    if (!func_offset) {\r\n        std::cout << \"failed to find symbol!\" << std::endl;\r\n        return 0;\r\n    }\r\n\r\n    \/* \u9644\u52a0\u8ddf\u8e2a\u70b9\u5904\u7406 *\/\r\n    uprobe_opts.retprobe = false;\r\n    skel->links.utest_add = bpf_program__attach_uprobe_opts(\r\n        skel->progs.utest_add,\r\n        -1, \/\/ uprobe \u7684\u8fdb\u7a0b ID\uff0c0 \u8868\u793a\u81ea\u8eab\uff08\u81ea\u5df1\u7684\u8fdb\u7a0b\uff09\uff0c-1 \u8868\u793a\u6240\u6709\u8fdb\u7a0b\r\n        \"\/home\/work\/project\/libbpf-demo\/examples\/test\/build\/utest\",\r\n        func_offset<\/span>, \/\/ offset for function\r\n        &uprobe_opts);\r\n    ...\r\n\r\n}\r\n<\/code><\/pre>\n
        \u7f16\u8bd1\u8fd0\u884c\u6d4b\u8bd5\uff1a<\/p>\n
        # \u7f16\u8bd1\r\nmkdir build && cd build\r\ncmake ..\r\nmake\r\n\r\n# \u8fd0\u884c\u7528\u6237\u81ea\u5b9a\u4e49\u7a0b\u5e8f\r\npkill utest\r\nnohup .\/utest &\r\n\r\n# \u6e05\u9664\u7b26\u53f7\u8868\r\nstrip --strip-all utest\r\n# \u542f\u52a8\r\nsudo .\/uprobe_symbol \r\n\r\n# \u76d1\u542c\u5185\u6838log\r\nsudo cat \/sys\/kernel\/debug\/tracing\/trace_pipe\r\n    utest-289573  [001] d...1 4174234.966051: bpf_trace_printk: utest_add ENTRY: a = 0, b = 1\r\n    utest-289573  [001] d...1 4174234.966051: bpf_trace_printk: utest_add EXIT: return = 1\r\n    utest-289573  [001] d...1 4174234.966051: bpf_trace_printk: utest_sub ENTRY: a = 0, b = 0\r\n    utest-289573  [001] d...1 4174234.966051: bpf_trace_printk: utest_sub EXIT: return = 0\r\n\r\n<\/code><\/pre>\n
        2.\u7c7b\u51fd\u6570\u7684\u63a2\u6d4b<\/h4>\n
        \u524d\u8fb9\u6211\u4eec\u63a2\u6d4b\u7684\u90fd\u662f\u7b80\u5355\u7684\u793a\u4f8b\u51fd\u6570\uff0c\u4e3a\u4e86\u8d34\u8fd1\u5b9e\u9645\u573a\u666f\uff0c\u6211\u4eec\u8fd9\u91cc\u6539\u4e3a\u5e26namespace\u3001class\u7684\u51fd\u6570\u63a2\u6d4b\u3002<\/p>\n
        \u81ea\u5b9a\u4e49\u7a0b\u5e8f\uff1a<\/p>\n
        \/**\r\n * \u7528\u6237\u7a7a\u95f4\u81ea\u5b9a\u4e49\u7a0b\u5e8f\r\n*\/\r\n#include <iostream>\r\n#include <stdio.h>\r\n#include <unistd.h>\r\n\r\nnamespace test {\r\n\r\nclass UTest {\r\npublic:\r\n    UTest(){\r\n        std::cout << \"UTest constructor\" << std::endl;\r\n    }\r\n\r\n    int utest_add(int a, int b)\r\n    {\r\n        return a + b;\r\n    }\r\n\r\n    int utest_sub(int a, int b)\r\n    {\r\n        return a - b;\r\n    }\r\n};\r\n\r\n}  \/\/ namespace test<\/code><\/pre>\n
        main\u5165\u53e3\uff1a<\/p>\n
        \/**\r\n * \u7528\u6237\u7a7a\u95f4\u81ea\u5b9a\u4e49\u7a0b\u5e8f\r\n*\/\r\n#include <memory>\r\n#include \"utest_class.h\"\r\n\r\nusing namespace test;\r\n\r\nint main(int argc, char **argv)\r\n{\r\n    int err, i;\r\n    auto obj = std::make_shared<UTest>();\r\n\r\n    for (i = 0;; i++) {\r\n        obj->utest_add(i, i + 1);\r\n        obj->utest_sub(i * i, i);\r\n\r\n        std::cout << \"i = \" << i << std::endl;\r\n\r\n        sleep(1);\r\n    }\r\n}<\/code><\/pre>\n
        \u4fee\u6539ebpf\u63a2\u6d4b\u7a0b\u5e8f\uff0c\u4f7f\u7528\u6539\u4e3aclass\u51fd\u6570\uff0c\u540c\u65f6\u4f7f\u7528pid\u6765\u81ea\u52a8\u83b7\u53d6bin\u6587\u4ef6\u4f4d\u7f6e\uff1a<\/p>\n
        int main(int argc, char **argv)\r\n{\r\n    ...\r\n    if(argc < 2){\r\n        std::cout << \"usage: .\/uprobe_symbol <pid>\" << std::endl;\r\n        return 0;\r\n    }\r\n    std::string symbol_dump_file = \".\/symbols-utest_class.dump\";\r\n    std::string func_name = \"test::UTest::utest_add<\/span>(int, int)\";\r\n    uint64_t func_offset = 0;\r\n    char binary_path[PATH_MAX];\r\n    pid_t pid<\/span> = atoi(argv[1]);\r\n\r\n    \/\/ \u901a\u8fc7pid\u83b7\u53d6\u53ef\u6267\u884c\u6587\u4ef6\u8def\u5f84\r\n    if (!pid){\r\n        std::cout << \"param pid invalid!\" << std::endl;\r\n        return 0;\r\n    }\r\n    if(!get_binary_file_by_pid(pid, binary_path<\/span>, sizeof(binary_path)) == 0){\r\n        std::cout << \"failed to get binary file by pid!\" << std::endl;\r\n        return 0;\r\n    }\r\n    std::cout << \"binary_path: \" << binary_path << std::endl;\r\n    \/\/ \u52a0\u8f7dsymbols.dump\u6587\u4ef6\r\n    std::ifstream is(symbol_dump_file, std::ios::binary);\r\n    auto symbol = new Symbol();\r\n    symbol->ParseFromIstream(&is);\r\n    is.close();\r\n    auto symbolMap = symbol->symbols();\r\n\r\n    \/\/ \u83b7\u53d6\u51fd\u6570\u5bf9\u5e94\u7b26\u53f7\u8868\u7684offset\r\n    func_offset<\/span> = symbolMap[func_name];\r\n    std::cout << \"func_offset: [\" << func_offset << \"] \" << func_name << std::endl;\r\n    if (!func_offset) {\r\n        std::cout << \"failed to find symbol!\" << std::endl;\r\n        return 0;\r\n    }\r\n\r\n    ...\r\n\r\n    \/* \u9644\u52a0\u8ddf\u8e2a\u70b9\u5904\u7406 *\/\r\n    uprobe_opts.retprobe = false;\r\n    skel->links.utest_add = bpf_program__attach_uprobe_opts(\r\n        skel->progs.utest_add,\r\n        -1,    \/\/ uprobe \u7684\u8fdb\u7a0b ID\uff0c0 \u8868\u793a\u81ea\u8eab\uff08\u81ea\u5df1\u7684\u8fdb\u7a0b\uff09\uff0c-1 \u8868\u793a\u6240\u6709\u8fdb\u7a0b\r\n        binary_path<\/span>,\r\n        func_offset<\/span>,    \/\/ offset for function\r\n        &uprobe_opts\r\n    );\r\n    ...\r\n<\/code><\/pre>\n
        \u7f16\u8bd1\u8fd0\u884c\u6d4b\u8bd5\uff1a<\/p>\n
        # \u7f16\u8bd1\r\nmkdir build && cd build\r\ncmake ..\r\nmake\r\n\r\n# \u8fd0\u884c\u7528\u6237\u81ea\u5b9a\u4e49\u7a0b\u5e8f\r\npkill utest_class\r\nnohup .\/utest_class &\r\n\r\n# \u542f\u52a8\r\npid=$(ps -ef | grep utest_class | grep -v grep | awk '{print $2}')\r\nsudo .\/uprobe_symbol ${pid}\r\n\r\n# \u76d1\u542c\u5185\u6838log\r\nsudo cat \/sys\/kernel\/debug\/tracing\/trace_pipe\r\n    utest-289573  [001] d...1 4175146.217611: bpf_trace_printk: utest_add ENTRY: a = 0, b = 1\r\n    utest-289573  [001] d...1 4175146.217611: bpf_trace_printk: utest_add EXIT: return = 1\r\n    utest-289573  [001] d...1 4175146.217611: bpf_trace_printk: utest_sub ENTRY: a = 0, b = 0\r\n    utest-289573  [001] d...1 4175146.217611: bpf_trace_printk: utest_sub EXIT: return = 0s<\/code><\/pre>\n
        \u4e09\u3001\u603b\u7ed3<\/h1>\n
        \u4eca\u5929\u6211\u4eec\u5c1d\u8bd5\u4e86\u628a\u7528\u6237\u7a7a\u95f4\u81ea\u5b9a\u4e49\u51fd\u6570\u63a2\u6d4b\u8fdb\u884c\u4e86\u5b8c\u5584\uff0c\u4e3b\u8981\u5305\u62ec\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n
          \n
        1. \u9488\u5bf9\u6e05\u9664\u7b26\u53f7\u8868\u7684\u4ea7\u51fa\u65e0\u6cd5\u627e\u5230\u7b26\u53f7\u7684\u95ee\u9898\uff0c\u6539\u4e3a\u63d0\u524d\u5bfc\u51fa\u7b26\u53f7\u8868\uff0c\u4f7f\u7528offset\u6765\u8fdb\u884c\u63a2\u6d4b\uff1b<\/li>\n
        2. \u4e3a\u8d34\u5408\u5b9e\u9645\u573a\u666f\uff0c\u5bf9namespace\u3001class\u7684func\u8fdb\u884c\u63a2\u6d4b\uff1b<\/li>\n
        3. \u9488\u5bf9\u4e0d\u540c\u673a\u5668\u4e8c\u8fdb\u5236\u4ea7\u51fa\u4f4d\u7f6e\u4e0d\u540c\u7684\u95ee\u9898\uff0c\u6539\u4e3a\u6839\u636epid\u81ea\u52a8\u83b7\u53d6\u4e8c\u8fdb\u5236\u6587\u4ef6\u4f4d\u7f6e\uff1b<\/li>\n<\/ol>\n
          \u597d\u4e86\uff0c\u4eca\u5929\u5c31\u5148\u5230\u8fd9\u91cc\uff0c\u5982\u679c\u4f60\u5bf9\u54ea\u65b9\u9762\u5185\u5bb9\u611f\u5174\u8da3\uff0c\u5e0c\u671b\u91cd\u70b9\u8bb2\u89e3\uff0c\u6b22\u8fce\u7ed9\u6211\u7559\u8a00\u4ea4\u6d41\uff5e<\/p>\n
           <\/p>\n
          yan 23.12.19<\/p>\n
           <\/p>\n
          \u53c2\u8003\uff1a<\/p>\n
          https:\/\/hansimov.gitbook.io\/csapp\/part2\/ch07-linking\/7.5-symbols-and-symbol-tables<\/p>\n
          https:\/\/workerwork.github.io\/posts\/sub-bin\/<\/p>\n
           <\/p>\n","protected":false},"excerpt":{"rendered":"
          \u4e0a\u4e00\u6b21\uff0c\u6211\u4eec\u901a\u8fc7uprobe\u5b9e\u73b0\u4e00\u4e2a\u5bf9\u7528\u6237\u7a7a\u95f4\u81ea\u5b9a\u4e49\u7a0b\u5e8f\u7684\u7279\u5b9a\u51fd\u6570\u51fa\u5165\u53e3\u8fdb\u884c\u4ee3\u7801\u6ce8\u5165\u548c\u63a2\u6d4b\u7684\u65b9\u6cd5\uff0c\u4f46\u5b83\u8fd8\u6709\u5f88\u591a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1317],"tags":[877,1318,1333],"_links":{"self":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8120"}],"collection":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8120"}],"version-history":[{"count":4,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8120\/revisions"}],"predecessor-version":[{"id":8154,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8120\/revisions\/8154"}],"wp:attachment":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8120"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}