{"id":1318,"date":"2018-06-03T00:29:42","date_gmt":"2018-06-02T16:29:42","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1318"},"modified":"2018-06-03T00:29:42","modified_gmt":"2018-06-02T16:29:42","slug":"%e4%b8%89%e6%ad%a5%e4%b8%8a%e6%89%8b-gdb","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1318","title":{"rendered":"\u4e09\u6b65\u4e0a\u624b GDB"},"content":{"rendered":"

\u8c03\u8bd5 C \u7a0b\u5e8f\uff0c\u66fe\u8ba9\u6211\u5f88\u56f0\u6270\u3002\u7136\u800c\u5f53\u6211\u4e4b\u524d\u5728\u5199\u6211\u7684\u64cd\u4f5c\u7cfb\u7edf<\/a>\u65f6\uff0c\u6211\u6709\u5f88\u591a\u7684 Bug \u9700\u8981\u8c03\u8bd5\u3002\u6211\u5f88\u5e78\u8fd0\u7684\u4f7f\u7528\u4e0a\u4e86 qemu \u6a21\u62df\u5668\uff0c\u5b83\u5141\u8bb8\u6211\u5c06\u8c03\u8bd5\u5668\u9644\u52a0\u5230\u6211\u7684\u64cd\u4f5c\u7cfb\u7edf\u3002\u8fd9\u4e2a\u8c03\u8bd5\u5668\u5c31\u662f\u00a0gdb<\/code>\u3002<\/p>\n

\u6211\u5f97\u89e3\u91ca\u4e00\u4e0b\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u00a0gdb<\/code>\u00a0\u5148\u505a\u4e00\u4e9b\u5c0f\u4e8b\u60c5\uff0c\u56e0\u4e3a\u6211\u53d1\u73b0\u521d\u5b66\u5b83\u7684\u65f6\u5019\u771f\u7684\u5f88\u6df7\u4e71\u3002\u6211\u4eec\u63a5\u4e0b\u6765\u4f1a\u5728\u4e00\u4e2a\u5c0f\u7a0b\u5e8f\u4e2d\uff0c\u8bbe\u7f6e\u65ad\u70b9\uff0c\u67e5\u770b\u5185\u5b58\u3002<\/p>\n

1\u3001 \u8bbe\u65ad\u70b9<\/h3>\n

\u5982\u679c\u4f60\u66fe\u7ecf\u4f7f\u7528\u8fc7\u8c03\u8bd5\u5668\uff0c\u90a3\u4f60\u53ef\u80fd\u5df2\u7ecf\u4f1a\u8bbe\u7f6e\u65ad\u70b9\u4e86\u3002<\/p>\n

\u4e0b\u9762\u662f\u4e00\u4e2a\u6211\u4eec\u8981\u8c03\u8bd5\u7684\u7a0b\u5e8f\uff08\u867d\u7136\u6ca1\u6709\u4efb\u4f55 Bug\uff09:<\/p>\n

    \n
  1. #<\/span>include<\/span> <<\/span>stdio<\/span>.<\/span>h<\/span>><\/span><\/code><\/li>\n
  2. void<\/span> do_thing<\/span>()<\/span> {<\/span><\/code><\/li>\n
  3. printf<\/span>(<\/span>\"Hi!\\n\"<\/span>);<\/span><\/code><\/li>\n
  4. }<\/span><\/code><\/li>\n
  5. int<\/span> main<\/span>()<\/span> {<\/span><\/code><\/li>\n
  6. do_thing<\/span>();<\/span><\/code><\/li>\n
  7. }<\/span><\/code><\/li>\n<\/ol>\n

    \u53e6\u5b58\u4e3a\u00a0hello.c<\/code>. \u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u00a0dbg<\/code>\u00a0\u8c03\u8bd5\u5b83\uff0c\u50cf\u8fd9\u6837\uff1a<\/p>\n

      \n
    1. bork@kiwi <\/span>~><\/span> gcc<\/span> -<\/span>g hello<\/span>.<\/span>c <\/span>-<\/span>o hello<\/span><\/code><\/li>\n
    2. bork@kiwi <\/span>~><\/span> gdb<\/span> .\/<\/span>hello<\/span><\/code><\/li>\n<\/ol>\n

      \u4ee5\u4e0a\u662f\u5e26\u8c03\u8bd5\u4fe1\u606f\u7f16\u8bd1\u00a0hello.c<\/code>\uff08\u4e3a\u4e86\u00a0gdb<\/code>\u00a0\u53ef\u4ee5\u66f4\u597d\u5de5\u4f5c\uff09\uff0c\u5e76\u4e14\u5b83\u4f1a\u7ed9\u6211\u4eec\u9192\u76ee\u7684\u63d0\u793a\u7b26\uff0c\u5c31\u50cf\u8fd9\u6837\uff1a<\/p>\n

        \n
      1. (<\/span>gdb<\/span>)<\/span><\/code><\/li>\n<\/ol>\n

        \u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u00a0break<\/code>\u00a0\u547d\u4ee4\u8bbe\u7f6e\u65ad\u70b9\uff0c\u7136\u540e\u4f7f\u7528\u00a0run<\/code>\u00a0\u5f00\u59cb\u8c03\u8bd5\u7a0b\u5e8f\u3002<\/p>\n

          \n
        1. (<\/span>gdb<\/span>)<\/span> break<\/span> do_thing <\/span><\/code><\/li>\n
        2. Breakpoint<\/span> 1<\/span> at <\/span>0x4004f8<\/span><\/code><\/li>\n
        3. (<\/span>gdb<\/span>)<\/span> run<\/span><\/code><\/li>\n
        4. Starting<\/span> program<\/span>:<\/span> \/home\/<\/span>bork<\/span>\/<\/span>hello <\/span><\/code><\/li>\n
        5. <\/code><\/li>\n
        6. Breakpoint<\/span> 1<\/span>,<\/span> 0x00000000004004f8<\/span> in<\/span> do_thing <\/span>()<\/span><\/code><\/li>\n<\/ol>\n

          \u7a0b\u5e8f\u6682\u505c\u5728\u4e86\u00a0do_thing<\/code>\u00a0\u5f00\u59cb\u7684\u5730\u65b9\u3002<\/p>\n

          \u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u00a0where<\/code>\u00a0\u67e5\u770b\u6211\u4eec\u6240\u5728\u7684\u8c03\u7528\u6808\u3002<\/p>\n

            \n
          1. (<\/span>gdb<\/span>)<\/span> where<\/span><\/code><\/li>\n
          2. #<\/span>0<\/span> do_thing <\/span>()<\/span> at hello<\/span>.<\/span>c<\/span>:<\/span>3<\/span><\/code><\/li>\n
          3. #<\/span>1<\/span> 0x08050cdb<\/span> in<\/span> main <\/span>()<\/span> at hello<\/span>.<\/span>c<\/span>:<\/span>6<\/span><\/code><\/li>\n
          4. (<\/span>gdb<\/span>)<\/span> <\/code><\/li>\n<\/ol>\n

            2\u3001 \u9605\u8bfb\u6c47\u7f16\u4ee3\u7801<\/h3>\n

            \u4f7f\u7528\u00a0disassemble<\/code>\u00a0\u547d\u4ee4\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230\u8fd9\u4e2a\u51fd\u6570\u7684\u6c47\u7f16\u4ee3\u7801\u3002\u68d2\u7ea7\u4e86\uff0c\u8fd9\u662f x86 \u6c47\u7f16\u4ee3\u7801\u3002\u867d\u7136\u6211\u4e0d\u662f\u5f88\u61c2\u5b83\uff0c\u4f46\u662f\u00a0callq<\/code>\u00a0\u8fd9\u4e00\u884c\u662f\u00a0printf<\/code>\u00a0\u51fd\u6570\u8c03\u7528\u3002<\/p>\n

              \n
            1. (<\/span>gdb<\/span>)<\/span> disassemble do_thing<\/span><\/code><\/li>\n
            2. Dump<\/span> of assembler code <\/span>for<\/span> function<\/span> do_thing<\/span>:<\/span><\/code><\/li>\n
            3. 0x00000000004004f4<\/span> <+<\/span>0<\/span>>:<\/span> push <\/span>%<\/span>rbp<\/span><\/code><\/li>\n
            4. 0x00000000004004f5<\/span> <+<\/span>1<\/span>>:<\/span> mov <\/span>%<\/span>rsp<\/span>,%<\/span>rbp<\/span><\/code><\/li>\n
            5. =><\/span> 0x00000000004004f8<\/span> <+<\/span>4<\/span>>:<\/span> mov $0x40060c<\/span>,%<\/span>edi<\/span><\/code><\/li>\n
            6. 0x00000000004004fd<\/span> <+<\/span>9<\/span>>:<\/span> callq <\/span>0x4003f0<\/span> <\/code><\/li>\n
            7. 0x0000000000400502<\/span> <+<\/span>14<\/span>>:<\/span> pop <\/span>%<\/span>rbp<\/span><\/code><\/li>\n
            8. 0x0000000000400503<\/span> <+<\/span>15<\/span>>:<\/span> retq <\/span><\/code><\/li>\n<\/ol>\n

              \u4f60\u4e5f\u53ef\u4ee5\u4f7f\u7528\u00a0disassemble<\/code>\u00a0\u7684\u7f29\u5199\u00a0disas<\/code>\u3002<\/p>\n

              3\u3001 \u67e5\u770b\u5185\u5b58<\/h3>\n

              \u5f53\u8c03\u8bd5\u6211\u7684\u5185\u6838\u65f6\uff0c\u6211\u4f7f\u7528\u00a0gdb<\/code>\u00a0\u7684\u4e3b\u8981\u539f\u56e0\u662f\uff0c\u4ee5\u786e\u4fdd\u5185\u5b58\u5e03\u5c40\u662f\u5982\u6211\u6240\u60f3\u7684\u90a3\u6837\u3002\u68c0\u67e5\u5185\u5b58\u7684\u547d\u4ee4\u662f\u00a0examine<\/code>\uff0c\u6216\u8005\u4f7f\u7528\u7f29\u5199\u00a0x<\/code>\u3002\u6211\u4eec\u5c06\u4f7f\u7528x<\/code>\u3002<\/p>\n

              \u901a\u8fc7\u9605\u8bfb\u4e0a\u9762\u7684\u6c47\u7f16\u4ee3\u7801\uff0c\u4f3c\u4e4e\u00a00x40060c<\/code>\u00a0\u53ef\u80fd\u662f\u6211\u4eec\u6240\u8981\u6253\u5370\u7684\u5b57\u7b26\u4e32\u5730\u5740\u3002\u6211\u4eec\u6765\u8bd5\u4e00\u4e0b\u3002<\/p>\n

                \n
              1. (<\/span>gdb<\/span>)<\/span> x<\/span>\/<\/span>s <\/span>0x40060c<\/span><\/code><\/li>\n
              2. 0x40060c<\/span>:<\/span> \"Hi!\"<\/span><\/code><\/li>\n<\/ol>\n

                \u7684\u786e\u662f\u8fd9\u6837\u3002x\/s<\/code>\u00a0\u4e2d\u00a0\/s<\/code>\u00a0\u90e8\u5206\uff0c\u610f\u601d\u662f\u201c\u628a\u5b83\u4f5c\u4e3a\u5b57\u7b26\u4e32\u5c55\u793a\u201d\u3002\u6211\u4e5f\u53ef\u4ee5\u201c\u5c55\u793a 10 \u4e2a\u5b57\u7b26\u201d\uff0c\u50cf\u8fd9\u6837\uff1a<\/p>\n

                  \n
                1. (<\/span>gdb<\/span>)<\/span> x<\/span>\/<\/span>10c<\/span> 0x40060c<\/span><\/code><\/li>\n
                2. 0x40060c<\/span>:<\/span> 72<\/span> 'H'<\/span> 105<\/span> 'i'<\/span> 33<\/span> '!'<\/span> 0<\/span> '\\000'<\/span> 1<\/span> '\\001'<\/span> 27<\/span> '\\033'<\/span> 3<\/span> '\\003'<\/span> 59<\/span> ';'<\/span><\/code><\/li>\n
                3. 0x400614<\/span>:<\/span> 52<\/span> '4'<\/span> 0<\/span> '\\000'<\/span><\/code><\/li>\n<\/ol>\n

                  \u4f60\u53ef\u4ee5\u770b\u5230\u524d\u56db\u4e2a\u5b57\u7b26\u662f\u00a0H<\/code>\u3001i<\/code>\u3001!<\/code>\u00a0\u548c\u00a0\\0<\/code>\uff0c\u5e76\u4e14\u5b83\u4eec\u4e4b\u540e\u7684\u662f\u4e00\u4e9b\u4e0d\u76f8\u5173\u7684\u4e1c\u897f\u3002<\/p>\n

                  \u6211\u77e5\u9053\u00a0gdb<\/code>\u00a0\u5f88\u591a\u5176\u4ed6\u7684\u4e1c\u897f\uff0c\u4f46\u662f\u6211\u4ecd\u7136\u4e0d\u662f\u5f88\u4e86\u89e3\u5b83\uff0c\u5176\u4e2d\u00a0x<\/code>\u00a0\u548c\u00a0break<\/code>\u00a0\u8ba9\u6211\u83b7\u5f97\u5f88\u591a\u3002\u4f60\u8fd8\u53ef\u4ee5\u9605\u8bfb\u00a0do umentation for examining memory<\/a>\u3002<\/p>\n

                  \n

                  via:\u00a0https:\/\/jvns.ca\/blog\/2014\/02\/10\/three-steps-to-learning-gdb\/<\/a><\/p>\n

                  \u4f5c\u8005\uff1aJulia Evans<\/a>\u00a0\u8bd1\u8005\uff1aTorival<\/a>\u00a0\u6821\u5bf9\uff1awxy<\/a><\/p>\n

                  \u672c\u6587\u7531\u00a0LCTT<\/a>\u00a0\u539f\u521b\u7f16\u8bd1\uff0cLinux\u4e2d\u56fd<\/a>\u00a0\u8363\u8a89\u63a8\u51fa<\/p>\n","protected":false},"excerpt":{"rendered":"

                  \u8c03\u8bd5 C \u7a0b\u5e8f\uff0c\u66fe\u8ba9\u6211\u5f88\u56f0\u6270\u3002\u7136\u800c\u5f53\u6211\u4e4b<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[118],"class_list":["post-1318","post","type-post","status-publish","format-standard","hentry","tag-02-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1318","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=1318"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1318\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=1318"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=1318"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=1318"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}