{"id":5895,"date":"2021-12-20T21:05:35","date_gmt":"2021-12-20T13:05:35","guid":{"rendered":"http:\/\/43.154.99.198\/?p=5895"},"modified":"2024-03-07T19:56:02","modified_gmt":"2024-03-07T11:56:02","slug":"elf-file-structure","status":"publish","type":"post","link":"https:\/\/www.wangonc.com\/index.php\/2021\/12\/20\/elf-file-structure\/","title":{"rendered":"ELF\u6587\u4ef6\u7ed3\u6784"},"content":{"rendered":"<h1>\u4e00\u3001\u683c\u5f0f\u6982\u8ff0<\/h1>\n<h2>1.1 elf\u6587\u4ef6\u7c7b\u578b<\/h2>\n<p>elf\u6587\u4ef6\u6709\u4e09\u79cd\u7c7b\u578b\uff1a\u53ef\u91cd\u5b9a\u5411\u6587\u4ef6\u3001\u53ef\u6267\u884c\u6587\u4ef6\u548c\u5171\u4eab\u76ee\u6807\u6587\u4ef6<\/p>\n<p>\u9002\u4e8e\u8fde\u63a5\u7684<strong>\u53ef\u91cd\u5b9a\u4f4d\u6587\u4ef6<\/strong>(relocatable file)\uff1a\u8fd9\u79cd\u6587\u4ef6\u662f\u7531\u7f16\u8bd1\u5668\u7f16\u8bd1\u6210\u7684.o\u6587\u4ef6\uff0c\u53ef\u4e0e\u5176\u5b83\u76ee\u6807\u6587\u4ef6\u4e00\u8d77\u521b\u5efa\u53ef\u6267\u884c\u6587\u4ef6\u548c\u5171\u4eab\u76ee\u6807\u6587\u4ef6\u3002\u6b64\u5916\uff0c.ko \u6587\u4ef6\u4e5f\u662f\u53ef\u91cd\u5b9a\u4f4d\u6587\u4ef6<\/p>\n<p>\u9002\u4e8e\u6267\u884c\u7684<strong>\u53ef\u6267\u884c\u6587\u4ef6<\/strong>(executable file)\uff1a\u8fd9\u79cd\u6587\u4ef6\u662f\u53ef\u4ee5\u76f4\u63a5\u7528\u4e8e\u6267\u884c\u7684elf\u6587\u4ef6\uff08\u5982vim\u3001gdb\u7b49\uff09\uff0c\u7528\u4e8e\u63d0\u4f9b\u7a0b\u5e8f\u7684\u8fdb\u7a0b\u6620\u50cf\uff0c\u52a0\u8f7d\u7684\u5185\u5b58\u6267\u884c\u3002<\/p>\n<p><strong>\u5171\u4eab\u76ee\u6807\u6587\u4ef6<\/strong>(shared object file)\uff1a\u8fd9\u79cd\u6587\u4ef6\u5c31\u662f\u52a8\u6001\u5e93\u6587\u4ef6\uff0c\u5373.so\u6587\u4ef6\u3002\u8fde\u63a5\u5668\u53ef\u5c06\u5b83\u4e0e\u5176\u5b83\u53ef\u91cd\u5b9a\u4f4d\u6587\u4ef6\u548c\u5171\u4eab\u76ee\u6807\u6587\u4ef6\u8fde\u63a5\u6210\u5176\u5b83\u7684\u76ee\u6807\u6587\u4ef6\uff0c\u52a8\u6001\u8fde\u63a5\u5668\u53c8\u53ef\u5c06\u5b83\u4e0e\u53ef\u6267\u884c\u6587\u4ef6\u548c\u5176\u5b83\u5171\u4eab\u76ee\u6807\u6587\u4ef6\u7ed3\u5408\u8d77\u6765\u521b\u5efa\u4e00\u4e2a\u8fdb\u7a0b\u6620\u50cf\u3002<\/p>\n<h2>1.2 elf\u6587\u4ef6\u89c6\u56fe<\/h2>\n<p>\u56e0\u4e3aelf\u6587\u4ef6\u65e2\u8981\u53c2\u4e0e\u94fe\u63a5\u53c8\u8981\u53c2\u4e0e\u6267\u884c\uff0c\u6240\u4ee5elf\u6587\u4ef6\u63d0\u4f9b\u4e86\u94fe\u63a5\u89c6\u56fe\u548c\u6267\u884c\u89c6\u56fe\u4e24\u79cd\u89c6\u56fe\uff0c\u5176\u7ed3\u6784\u793a\u610f\u56fe\u5982\u4e0b<br \/>\n<div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/image-1640004490859.png'><img class=\"lazyload lazyload-style-3\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/image-1640004490859.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\" \/><\/div><\/p>\n<p><strong>\u94fe\u63a5\u89c6\u56fe<\/strong>\uff1a\u9759\u6001\u94fe\u63a5\u5668\u4f1a\u4ee5\u94fe\u63a5\u89c6\u56fe\u89e3\u6790elf\u3002\u4f7f\u7528\u94fe\u63a5\u89c6\u56fe\u65f6\u53ef\u4ee5\u6ca1\u6709\u7a0b\u5e8f\u5934\u8868<\/p>\n<p><strong>\u6267\u884c\u89c6\u56fe<\/strong>\uff1a\u52a8\u6001\u8fde\u63a5\u5668\uff08\u5373\u52a0\u8f7d\u5668\uff0c\u5982 x86 \u67b6\u6784 linux \u4e0b\u7684 \/lib\/ld-linux.so.2 \u6216\u8005\u5b89\u5353\u7cfb\u7edf\u4e0b\u7684 \/system\/linker\uff09\u4f1a\u4ee5\u6267\u884c\u89c6\u56fe\u89e3\u6790elf\u3002\u4f7f\u7528\u6267\u884c\u89c6\u56fe\u65f6\u53ef\u4ee5\u6ca1\u6709\u8282\u8868<\/p>\n<h1>\u4e8c\u3001ELF Header<\/h1>\n<p>ELF Header\u7ed3\u6784\u7ed9\u51fa\u4e86\u7a0b\u5e8f\u7684\u7c7b\u522b\u3001\u67b6\u6784\u3001\u5165\u53e3\u7b49\u57fa\u672c\u4fe1\u606f\u3002\u5728linux\u4e2d\u53ef\u4ee5\u4f7f\u7528readelf -h\u547d\u4ee4\u6765\u67e5\u770b\u4e00\u4e2aelf\u6587\u4ef6\u7684elf\u5934\uff0c\u5982\u4e0b\u56fe\u6240\u793a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/image-1640004508290.png'><img class=\"lazyload lazyload-style-3\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/image-1640004508290.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"file\/\" \/><\/div><\/p>\n<p>\u5bf9\u4e8e32\u4f4delf\u7a0b\u5e8f\u6765\u8bf4\uff0c\u5176\u957f\u5ea6\u56fa\u5b9a\u4e3a0x34\uff0c\u800c64\u4f4delf\u6587\u4ef6\u7684elf\u5934\u957f\u5ea6\u4e3a0x40\u30023\u3002\u4ee532\u4f4d\u4e3a\u4f8b\uff0c\u5176\u5982\u4e0b(\u8fd9\u4e2a\u7ed3\u6784\u7684\u5b9a\u4e49\u4f4d\u4e8e\/usr\/include\/elf.h\u4e2d)\uff0c\uff1a<\/p>\n<pre><code class=\"language-cpp\">#define EI_NIDENT (16)\ntypedef struct\n{\n  unsigned char e_ident[EI_NIDENT]; \/* Magic number and other info *\/\n  Elf32_Half    e_type;         \/* Object file type *\/\n  Elf32_Half    e_machine;      \/* Architecture *\/\n  Elf32_Word    e_version;      \/* Object file version *\/\n  Elf32_Addr    e_entry;        \/* Entry point virtual address *\/\n  Elf32_Off e_phoff;        \/* Program header table file offset *\/\n  Elf32_Off e_shoff;        \/* Section header table file offset *\/\n  Elf32_Word    e_flags;        \/* Processor-specific flags *\/\n  Elf32_Half    e_ehsize;       \/* ELF header size in bytes *\/\n  Elf32_Half    e_phentsize;        \/* Program header table entry size *\/\n  Elf32_Half    e_phnum;        \/* Program header table entry count *\/\n  Elf32_Half    e_shentsize;        \/* Section header table entry size *\/\n  Elf32_Half    e_shnum;        \/* Section header table entry count *\/\n  Elf32_Half    e_shstrndx;     \/* Section header string table index *\/\n} Elf32_Ehdr;<\/code><\/pre>\n<p>\u5176\u5404\u4e2a\u5b57\u6bb5\u7684\u542b\u4e49\u5982\u4e0b\uff08\u5176\u4e2a\u5b57\u6bb5\u53d6\u503c\u53ef\u4ee5\u67e5\u9605\/usr\/include\/elf.h\uff09\uff1a<\/p>\n<p>e_ident \uff1a ELF\u7684\u4e00\u4e9b\u6807\u8bc6\u4fe1\u606f<\/p>\n<p>e_type\uff1a\u7528\u4e8e\u6807\u8bb0\u6587\u4ef6\u7c7b\u522b\uff0c\u5373\u672c\u6587\u5f00\u5934\u6240\u8bf4\u7684\u4e09\u79cd\u4e09\u7c7b\u522b\uff1b\u9664\u6b64\u4e4b\u5916\uff0c\u8fd8\u6709\u5728linux\u7cfb\u7edf\u5f02\u5e38\u65f6\u4ea7\u751f\u7684coredump\u7c7b\u578b\u548c\u7528\u4e8e\u6807\u8bb0\u7279\u5b9a\u5904\u7406\u5668\u7684\u7c7b\u522b<\/p>\n<p>e_machine \uff1a \u6587\u4ef6\u7684\u76ee\u6807\u4f53\u7cfb\u67b6\u6784\uff0c\u6bd4\u5982ARM\u7b49<\/p>\n<p>e_version : \u76ee\u6807\u6587\u4ef6\u7684\u7248\u672c\uff0c0\u4e3a\u975e\u6cd5\u7248\u672c\uff0c1\u4e3a\u5f53\u524d\u7248\u672c<\/p>\n<p>e_entry \uff1a \u7a0b\u5e8f\u5165\u53e3\u7684\u865a\u62df\u5730\u5740\u3002\u5982\u679c\u7a0b\u5e8f\u6ca1\u6709\u5165\u53e3\uff0c\u8be5\u503c\u53ef\u4ee5\u4e3a0<\/p>\n<p>e_phoff \uff1a \u7a0b\u5e8f\u5934\u90e8\u8868\u504f\u79fb\u5730\u5740\u3002\u5982\u679c\u7a0b\u5e8f\u6ca1\u6709\u7a0b\u5e8f\u5934\u90e8\u8868\u683c,\u53ef\u4ee5\u4e3a0\uff0c\u5982\u679c\u6587\u4ef6\u6709\u7a0b\u5e8f\u5934\u90e8\u8868\uff0c\u90a3\u4e48\u4e00\u822c\u6765\u8bf4\uff0c\u8fd9\u4e2a\u503c\u7b49\u4e8eelf\u5934\u7684\u5927\u5c0f\u3002\u56e0\u4e3a\u5728elf\u5934\u4e4b\u540e\u7d27\u63a5\u7740\u5c31\u662f\u7a0b\u5e8f\u5934\u8868\u3002<\/p>\n<p>e_shoff \uff1a \u8282\u533a\u5934\u90e8\u8868\u504f\u79fb\u5730\u5740\u3002\u5982\u679c\u6587\u4ef6\u6ca1\u6709\u8282\u533a\u5934\u90e8\u8868\u683c,\u53ef\u4ee5\u4e3a0\u3002<\/p>\n<p>e_flags \uff1a\u4fdd\u5b58\u4e0e\u6587\u4ef6\u76f8\u5173\u7684\uff0c\u7279\u5b9a\u4e8e\u5904\u7406\u5668\u7684\u6807\u5fd7<\/p>\n<p>e_ehsize \uff1aELF\u5934\u7684\u5927\u5c0f\u3002\u4e00\u822c\u6765\u8bf4\uff0c32\u4f4d\u4e0belf\u5934\u5927\u5c0f\u4e3a0x34\uff0c64\u4f4d\u4e0b\u4e3a0x40<\/p>\n<p>e_phentsize \uff1a \u6bcf\u4e2a\u7a0b\u5e8f\u5934\u90e8\u8868\u8868\u9879\u7684\u5927\u5c0f\u3002\u4e00\u822c\u6765\u8bf4\uff0c32\u4f4d\u4e0b\u5176\u5927\u5c0f\u4e3a0x2A\uff0c64\u4f4d\u4e0b\u5176\u5927\u5c0f\u4e3a0x36\u3002<\/p>\n<p>e_phnum \uff1a\u7a0b\u5e8f\u5934\u90e8\u8868\u8868\u9879\u7684\u6570\u91cf<\/p>\n<p>e_shentsize\uff1a\u6bcf\u4e2a\u8282\u533a\u5934\u90e8\u8868\u8868\u9879\u7684\u5927\u5c0f\u3002\u4e00\u822c\u6765\u8bf4\uff0c32\u4f4d\u4e0b\u5176\u5927\u5c0f\u4e3a0x2E\uff0c64\u4f4d\u4e0b\u5176\u5927\u5c0f\u4e3a0x3A\u3002<\/p>\n<p>e_shnum \uff1a \u8282\u533a\u5934\u90e8\u8868\u8868\u9879\u7684\u6570\u91cf<\/p>\n<p>e_shstrndx\uff1a\u8282\u533a\u540d\u79f0\u8282\u8868\u7684\u4f4d\u7f6e\u3002\u5982\u679c\u6587\u4ef6\u6ca1\u6709\u8282\u533a\u540d\u79f0\u5b57\u7b26\u4e32\u8868,\u6b64\u53c2\u6570\u53ef\u4ee5\u4e3aSHN_UNDEF\uff1b\u5982\u679c\u6587\u4ef6\u5b58\u5728\u8282\u533a\u540d\u79f0\u8282\uff0c\u90a3\u4e48\u4e00\u822c\u6765\u8bf4\uff0c\u8fd9\u4e2a\u503c\u4e3ae_shnum &#8211; 1\uff0c\u5373\u6700\u540e\u4e00\u4e2a\u8282\u3002<\/p>\n<blockquote>\n<p>32\u4f4d\u7684elf header\u7ed3\u6784\uff08Elf32_Ehdr\uff09\u4e0e64\u4f4d\u7684elf header\uff08Elf64_Ehdr\uff09\u5b57\u6bb5\u5b8c\u5168\u76f8\u540c\uff0c\u5dee\u5f02\u5728\u4e8e\u7528\u4e8e\u5b58\u653e\u5730\u5740\u7684\u4e09\u4e2a\u5b57\u6bb5\u2014\u2014\u7a0b\u5e8f\u5165\u53e3\u5730\u5740\uff08e_entry\uff09\u3001\u7a0b\u5e8f\u5934\u504f\u79fb\uff08e_phoff\uff09\u548c\u8282\u5934\u504f\u79fb\uff08e_shoff\uff09\u7684\u4e09\u4e2a\u5b57\u6bb5\u572864\u4f4d\u4e2d\u957f\u5ea6\u4e3a8\u5b57\u8282\uff0c\u800c\u572832\u4f4d\u4e2d\u957f\u5ea6\u4e3a4\u5b57\u8282\u3002<\/p>\n<\/blockquote>\n<h2>2.1 e_ident<\/h2>\n<p>e_ident\u662f\u4e00\u4e2a\u7ed3\u6784\u4f53\uff0c\u5176\u5b58\u653e\u4e86elf\u8bf8\u5982\u6587\u4ef6\u7c7b\u578b\u3001\u7f16\u7801\u7c7b\u578b\u7b49\u7684\u6807\u8bc6\u6027\u4fe1\u606f\u3002\u8fd9\u4e2a\u7ed3\u6784\u572832\u4f4d\u548c64\u4f4delf\u4e2d\u90fd\u5b58\u5728\uff0c\u5e76\u4e14\u5b8c\u5168\u76f8\u540c\u3002\u5176\u8bfb\u53d6\u4e0d\u53d7\u7f16\u7801\u7c7b\u578b\u7b49\u4fe1\u606f\u7684\u5f71\u54cd\u3002\u5176\u5404\u4e2a\u5b57\u6bb5\u542b\u4e49\u53ca\u53d6\u503c\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u540d\u79f0<\/th>\n<th>\u5143\u7d20\u4e0b\u6807\u503c<\/th>\n<th>\u542b\u4e49<\/th>\n<th>\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>EI_MAG0<\/td>\n<td>0<\/td>\n<td>\u9b54\u6570(Magic Number)\u7684\u4e00\u90e8\u5206,\u6807\u5fd7\u6b64\u6587\u4ef6\u662f\u4e00\u4e2aELF \u76ee\u6807\u6587\u4ef6<\/td>\n<td>\u5982\u679c\u4e3aelf\u6587\u4ef6\uff0c\u6539\u5b57\u6bb5\u53d6\u503c\u4e3ae_ident[ET_MAG0]=0x7f<\/td>\n<\/tr>\n<tr>\n<td>EI_MAG1<\/td>\n<td>1<\/td>\n<td>\u9b54\u6570(Magic Number)\u7684\u4e00\u90e8\u5206,\u6807\u5fd7\u6b64\u6587\u4ef6\u662f\u4e00\u4e2aELF \u76ee\u6807\u6587\u4ef6<\/td>\n<td>\u5982\u679c\u4e3aelf\u6587\u4ef6\uff0c\u8be5\u5b57\u6bb5\u53d6\u503c\u4e3ae_ident[EI_MAGl]=\u2019E\u2019<\/td>\n<\/tr>\n<tr>\n<td>EI_MAG2<\/td>\n<td>2<\/td>\n<td>\u9b54\u6570(Magic Number)\u7684\u4e00\u90e8\u5206,\u6807\u5fd7\u6b64\u6587\u4ef6\u662f\u4e00\u4e2aELF \u76ee\u6807\u6587\u4ef6<\/td>\n<td>\u5982\u679c\u4e3aelf\u6587\u4ef6\uff0c\u8be5\u5b57\u6bb5\u53d6\u503c\u4e3ae_ident[EI_MAG2]=\u2019L\u2019<\/td>\n<\/tr>\n<tr>\n<td>EI_MAG3<\/td>\n<td>3<\/td>\n<td>\u9b54\u6570(Magic Number)\u7684\u4e00\u90e8\u5206,\u6807\u5fd7\u6b64\u6587\u4ef6\u662f\u4e00\u4e2aELF \u76ee\u6807\u6587\u4ef6<\/td>\n<td>\u5982\u679c\u4e3aelf\u6587\u4ef6\uff0c\u8be5\u5b57\u6bb5\u53d6\u503c\u4e3ae_ident[EI_MAG3]=\u2019F\u2019<\/td>\n<\/tr>\n<tr>\n<td>EI_CLASS<\/td>\n<td>4<\/td>\n<td>\u6807\u8bc6\u6587\u4ef6\u7684\u7c7b\u522b\uff0c\u537332\u4f4d\u8fd8\u662f64\u4f4d\u7b49<\/td>\n<td>\u5176\u5b8f\u5b9a\u4e49\u3001\u53d6\u503c\u548c\u542b\u4e49\u5982\u4e0b\uff1a<br \/> ELFCLASSNONE 0 \u975e\u6cd5\u7c7b\u522b <br \/>  ELFCLASS32 1 32 \u4f4d\u76ee\u6807 <br \/>  ELFCLASS64 2 64 \u4f4d\u76ee\u6807<\/td>\n<\/tr>\n<tr>\n<td>EI_DATA<\/td>\n<td>5<\/td>\n<td>\u6570\u636e\u7f16\u7801\u7c7b\u578b<\/td>\n<td>\u5176\u5b8f\u5b9a\u4e49\u3001\u53d6\u503c\u548c\u542b\u4e49\u5982\u4e0b\uff1a  <br \/> ELFDATANONE 0 \u975e\u6cd5\u7f16\u7801\u7c7b\u578b  <br \/> ELFDATA2LSB 1 \u5c0f\u7aef\u5e8f   <br \/>ELFDATA2MSB 2 \u5927\u7aef\u5e8f<\/td>\n<\/tr>\n<tr>\n<td>EI_VERSION<\/td>\n<td>6<\/td>\n<td>ELF\u5934\u7684\u7248\u672c\u6807\u8bb0<\/td>\n<td>\u5f53\u503c\u4e3a\u5b8f\u5b9a\u4e49E_CURRENT (1)\u65f6\u610f\u4e3a\u5f53\u524d\u7248\u672c\u6216\u7248\u672c\u53ef\u7528\uff0c\u4e3aE_NONE (0)\u65f6\u610f\u4e3a\u975e\u6cd5\u7248\u672c<\/td>\n<\/tr>\n<tr>\n<td>EI_PAD<\/td>\n<td>7<\/td>\n<td>\u8865\u9f50\u5b57\u8282\u5f00\u59cb\u5904<\/td>\n<td>\u8fd9\u6bb5\u5185\u5bb9\u662felf\u5934\u672a\u4f7f\u7528\u7684\u5b57\u8282\uff0c\u5176\u5185\u5bb9\u4e3a0<\/td>\n<\/tr>\n<tr>\n<td>EI_NIDENT<\/td>\n<td>16<\/td>\n<td>e_ident[]\u5927\u5c0f<\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>2.2 e_entry<\/h2>\n<p>e_entry\u5373\u7a0b\u5e8f\u7684\u5165\u53e3\u5730\u5740\uff0c\u5176\u6307\u5411\u7684\u662f\u52a0\u8f7d\u7a0b\u5e8f\u540e\u7a0b\u5e8f\u6240\u6267\u884c\u7684\u7b2c\u4e00\u884c\u4ee3\u7801\u3002\u4f46\u662f\u5bf9\u4e8e\u4e0d\u9700\u8981\u6267\u884c\u7684elf\u6587\u4ef6\uff0c\u4f8b\u5982\u53ef\u91cd\u5b9a\u4f4d\u6587\u4ef6\u6765\u8bf4\uff0c\u5176\u5165\u53e3\u5730\u5740\u53ef\u4ee5\u4e3a0\uff0c\u56e0\u4e3a\u5176\u53ea\u9700\u8981\u7528\u4e8e\u94fe\u63a5\u5373\u53ef\uff0c\u5e76\u4e0d\u9700\u8981\u6267\u884c\u3002<\/p>\n<p>\u5bf9\u4e8e\u5171\u4eab\u6587\u4ef6\u6765\u8bf4\uff0c\u901a\u8fc7\u7ed9\u52a8\u6001\u94fe\u63a5\u5e93\u7f16\u5199main\u51fd\u6570\u7684\u65b9\u5f0f\u53ef\u4ee5\u7ed9\u5176\u6dfb\u52a0\u5165\u53e3\u5730\u5740\uff0c\u4f46\u662f\u5e76\u4e0d\u4f1a\u5b9e\u9645\u6267\u884c\uff0c\u6240\u4ee5\u52a8\u6001\u94fe\u63a5\u5e93\u4e5f\u53ef\u4ee5\u6ca1\u6709\u5165\u53e3\u5730\u5740\u3002<\/p>\n<p>\u800c\u53ef\u6267\u884c\u6587\u4ef6\u662f\u4e00\u5b9a\u62e5\u6709\u5165\u53e3\u5730\u5740\u7684\uff0c\u5176\u5165\u53e3\u5730\u5740\u6307\u5411\u7684\u51fd\u6570\u662fstart\u51fd\u6570\uff08\u975emain\u51fd\u6570\uff09\u3002_start\u51fd\u6570\u7684\u4f5c\u7528\u5c31\u662f\u5728\u7a0b\u5e8f\u6267\u884c\u524d\u8fdb\u884c\u4e00\u4e9b\u521d\u59cb\u5316\u51fd\u6570\uff0c\u7136\u540e\u8c03\u7528main\u51fd\u6570\uff0c\u6700\u540e\u8fdb\u884c\u4e00\u4e9b\u6e05\u7406\u5de5\u4f5c\u3002<\/p>\n<p>\u6240\u4ee5\u53ef\u4ee5\u901a\u8fc7\u81ea\u5df1\u5b9e\u73b0start\u51fd\u6570\u7684\u65b9\u5f0f\u6765\u5b9a\u4e49\u51fd\u6570\u7684\u5165\u53e3\u3002\u4f7f\u7528<code>-nostartfiles<\/code>\u53c2\u6570\u6765\u544a\u77e5\u7f16\u8bd1\u5668\u4e0d\u94fe\u63a5\u6807\u51c6\u542f\u52a8\u6587\u4ef6\uff0c\u7136\u540e\u4f7f\u7528\u5982\u4e0b\u4ee3\u7801\u6765\u81ea\u5df1\u5b9e\u73b0_start\u51fd\u6570\uff0c\u8fd9\u6837\u7a0b\u5e8f\u7684\u5165\u53e3\u5730\u5740\u4f1a\u76f4\u63a5\u6307\u5411\u81ea\u5df1\u5b9e\u73b0\u7684_start\u51fd\u6570\u3002<\/p>\n<pre><code class=\"language-c\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\nint _start()\n{\n    printf(hello start);\n    exit(0);\n\n}<\/code><\/pre>\n<blockquote>\n<p>\u4e0a\u8ff0\u4ee3\u7801\u4e2d\u5fc5\u987b\u8981\u6dfb\u52a0exit(0)\uff0c\u8fd9\u662f\u56e0\u4e3a_start\u51fd\u6570\u6267\u884c\u7ed3\u675f\u540e\u7a0b\u5e8f\u5c31\u7ed3\u675f\u4e86\uff0c\u9700\u8981\u6267\u884cexit()\u51fd\u6570\u6765\u8fdb\u884c\u4e00\u4e9b\u6e05\u7406\u5de5\u4f5c\u3002<\/p>\n<\/blockquote>\n<h2>2.3 \u4e8c\u8fdb\u5236\u6587\u4ef6\u4e2d\u7684elf\u5934<\/h2>\n<p>elf\u6587\u4ef6\u53ef\u80fd\u7531\u4e8e\u52a0\u58f3\u7b49\u624b\u6bb5\u4f7f\u5f97elf\u7ed3\u6784\u906d\u5230\u7834\u574f\uff0c\u4ece\u800c\u4f7f\u5f97\u5206\u6790\u5de5\u5177\u65e0\u6cd5\u6b63\u5e38\u5206\u6790\uff0c\u8fd9\u662f\u5c31\u9700\u8981\u81ea\u5df1\u624b\u52a8\u6765\u5206\u6790\u4e8c\u8fdb\u5236\u6587\u4ef6\uff0c\u5e76\u5bf9\u5176\u8fdb\u884c\u4fee\u590d\uff0c\u6240\u4ee5\u53ef\u4ee5\u8bc6\u522belf\u7ed3\u6784\u5728\u4e8c\u8fdb\u5236\u6587\u4ef6\u4e2d\u7684\u72b6\u6001\u662f\u5f88\u6709\u5fc5\u8981\u7684\u3002\u4e0b\u9762\u662f32\u4f4delf\u6587\u4ef6\u7684elf\u5934\u7684\u793a\u4f8b\uff0864\u4f4d\u4ec5\u5730\u5740\u957f\u5ea6\u4e0d\u540c\uff09\uff1a<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/elf\u5934\u7ed3\u6784-1024x384.png'><img class=\"lazyload lazyload-style-3\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  decoding=\"async\" data-original=\"https:\/\/www.wangonc.com\/wp-content\/uploads\/2021\/12\/elf\u5934\u7ed3\u6784-1024x384.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h1>\u4e09\u3001\u8282\u533a\uff08Sections\uff09<\/h1>\n<p>\u8282\u533a\u4e2d\u5305\u542b\u4e86\u76ee\u6807\u6587\u4ef6\u7684\u9664ELF \u5934\u3001\u7a0b\u5e8f\u5934\u8868\u3001\u8282\u533a\u5934\u8868\u5728\u5185\u7684\u6240\u6709\u4fe1\u606f\u3002<\/p>\n<h2>3.1 section_header_table<\/h2>\n<p>\u8282\u533a\u5934\u8868\uff08SHT\uff09\u5b58\u653e\u4e86\u6240\u6709\u7684\u8282\u533a\u4fe1\u606f\uff0c\u5176\u51b3\u5b9a\u4e86\u76ee\u6807\u6587\u4ef6\u5185\u6709\u90a3\u4e9b\u8282\u533a\u3002\u5728elf\u5934\u4e2d\u5df2\u7ecf\u901a\u8fc7e_shnum\u5b57\u6bb5\u7ed9\u51fa\u76ee\u6807\u6587\u4ef6\u5185\u5171\u6709\u591a\u5c11\u8282\u533a\uff0c\u4e5f\u5c31\u662fSHT\u7684\u8868\u9879\u6570\u76ee\u3002SHT\u4e2d\u7684\u9879\u662f\u8282\u533a\u5934\u7ed3\u6784\u4f53\uff0c\u5176\u4ee3\u7801\u5982\u4e0b\uff08\u4ee532\u4f4d\u4e3a\u4f8b\uff09\uff1a<\/p>\n<pre><code class=\"language-cpp\">typedef struct\n{\n  Elf32_Word    sh_name;        \/* Section name (string tbl index) *\/\n  Elf32_Word    sh_type;        \/* Section type *\/\n  Elf32_Word    sh_flags;       \/* Section flags *\/\n  Elf32_Addr    sh_addr;        \/* Section virtual addr at execution *\/\n  Elf32_Off sh_offset;      \/* Section file offset *\/\n  Elf32_Word    sh_size;        \/* Section size in bytes *\/\n  Elf32_Word    sh_link;        \/* Link to another section *\/\n  Elf32_Word    sh_info;        \/* Additional section information *\/\n  Elf32_Word    sh_addralign;       \/* Section alignment *\/\n  Elf32_Word    sh_entsize;     \/* Entry size if section holds table *\/\n} Elf32_Shdr;<\/code><\/pre>\n<p>\u5176\u5b57\u6bb5\u89e3\u91ca\u548c\u8bf4\u660e\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u540d\u79f0<\/th>\n<th>\u542b\u4e49<\/th>\n<th>\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>sh_name<\/td>\n<td>\u5f53\u524d\u8282\u7684\u540d\u79f0\u5728\u8282\u540d\u79f0\u8868\u4e2d\u7684\u7d22\u5f15\u3002<\/td>\n<td>\u8282\u540d\u79f0\u8868\u5728\u8282\u533a\u7684\u7d22\u5f15\u4f1a\u88ab\u8bb0\u5f55\u5728elf\u5934\u7684e_shtrndx\u5b57\u6bb5\u4e2d\uff0c\u4f46\u662f\u76ee\u6807\u6587\u4ef6\u4e5f\u53ef\u4ee5\u6ca1\u6709\u8282\u533a\u540d\u79f0\u8868\u3002<\/td>\n<\/tr>\n<tr>\n<td>sh_type<\/td>\n<td>\u8282\u533a\u7684\u7c7b\u578b\uff0c\u7528\u4e8e\u6807\u8bb0\u4e0d\u540c\u4f5c\u7528\u548c\u5185\u5bb9\u7684\u8282\u533a\uff0c\u4f8b\u5982SHT_STRTAB\u7c7b\u578b\u7684\u8282\u533a\u610f\u5473\u7740\u5f53\u524d\u8282\u533a\u5b58\u653e\u4e86\u8282\u533a\u540d\u79f0\u8868\u3002<\/td>\n<td>\u8be6\u7ec6\u7c7b\u578b\u53ca\u8bf4\u660e\u89c1\u4e0b\u6587<\/td>\n<\/tr>\n<tr>\n<td>sh_flags<\/td>\n<td>\u7528\u4e8e\u8bb0\u5f55\u8282\u533a\u5185\u5bb9\u5185\u5b58\u5c5e\u6027\uff0c\u5373\u8be5\u8282\u533a\u7684\u6570\u636e\u662f\u5426\u53ef\u4ee5\u88ab\u8bfb\u5199\u6267\u884c\u3002\u5176\u5c5e\u6027\u5206\u4e3a\u57fa\u672c\u53ef\u5206\u4e3a\u8bfb\u5199\u6267\u884c\u4e09\u4e2a\u3002\u8be5\u5b57\u6bb5\u4f1a\u5c06\u76ee\u6807\u6587\u4ef6\u6240\u62e5\u6709\u7684\u57fa\u672c\u5c5e\u6027\u7684\u53d6\u503c\u8fdb\u884c\u6216\u64cd\u4f5c\u4f5c\u4e3a\u6700\u7ec8\u7684\u53d6\u503c\u3002\u4f8b\u5982\u67d0\u6587\u4ef6\u7684\u67d0\u5b57\u6bb5\u5177\u6709\u8bfb\u5199\u4e24\u79cd\u5c5e\u6027\uff0c\u8be5\u5b57\u6bb5\u503c\u5e94\u4e3a0x1 | 0x2\uff08\u53730b1 | 0b10\uff09<\/td>\n<td>\u8be5\u5b57\u6bb5\u53d6\u503c\u7684\u5b8f\u5b9a\u4e49\u548c\u542b\u4e49\u5982\u4e0b\uff1a <br \/> SHF_WRITE 0x1 \u6570\u636e\u53ef\u5199<br \/> SHF_ALLOC 0x2 \u6570\u636e\u53ef\u8bfb <br \/>SHF_EXECINSTR 0x4 \u6570\u636e\u53ef\u6267\u884c <br \/>SHF_MASKPROC 0xF0000000<\/td>\n<\/tr>\n<tr>\n<td>sh_addr<\/td>\n<td>\u5f53\u524d\u8282\u5728\u76ee\u6807\u6587\u4ef6\u6267\u884c\u65f6\u88ab\u6620\u5c04\u8fdb\u5185\u5b58\u65f6\u7684\u865a\u62df\u5730\u5740\u3002\u5982\u679c\u5f53\u524d\u8282\u5e76\u4e0d\u9700\u8981\u88ab\u6620\u5c04\uff0c\u8fd9\u4e2a\u503c\u4e3a0\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_offset<\/td>\n<td>\u5f53\u524d\u8282\u7684\u6570\u636e\u5728\u76ee\u6807\u6587\u4ef6\u4e2d\u7684\u504f\u79fb\u5730\u5740\u3002\u8fd9\u4e2a\u5b57\u6bb5\u548csh_addr\u5e76\u4e0d\u4e00\u5b9a\u76f8\u7b49\uff0c\u8fd9\u662f\u56e0\u4e3a\u76ee\u6807\u6587\u4ef6\u7684\u7ed3\u6784\u548c\u5176\u6620\u5c04\u5230\u5185\u5b58\u4e2d\u7684\u7ed3\u6784\u5e76\u4e0d\u5b8c\u5168\u76f8\u540c\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_size<\/td>\n<td>\u5f53\u524d\u8282\u533a\u6240\u5bf9\u5e94\u6570\u636e\u7684\u5927\u5c0f\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_link<\/td>\n<td>\u8be5\u5b57\u8282\u8868\u660e\u4e86\u5f53\u524d\u8282\u533a\u6240\u5173\u8054\u4f7f\u7528\u7684\u8868\u7684\u8282\u533a\u7684\u7d22\u5f15\uff0c\u4e3b\u8981\u4e0e\u94fe\u63a5\u6216\u91cd\u5b9a\u4f4d\u6709\u5173\u7684\u8282\u4f1a\u4f7f\u7528\u3002\u53d7\u8282\u7c7b\u578b\u5f71\u54cd\uff0c\u4f1a\u5177\u6709\u4e0d\u540c\u7684\u542b\u4e49\u3002\u4f8b\u5982SHT_DYNAMIC\u7c7b\u578b\u7684\u8282\u533a\u7684\u8be5\u5b57\u6bb5\u5c31\u53ef\u4ee5\u5b58\u653e\u5176\u6240\u9700\u8981\u7684\u52a8\u6001\u94fe\u63a5\u7b26\u53f7\u8868\u7684\u7d22\u5f15\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_info<\/td>\n<td>\u9644\u52a0\u4fe1\u606f\uff0c\u53d7\u8282\u7c7b\u578b\u7684\u5f71\u54cd\u5177\u6709\u4e0d\u540c\u7684\u542b\u4e49\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_addralign<\/td>\n<td>\u8be5\u503c\u8868\u660e\u4e86\u5730\u5740\u7684\u5bf9\u9f50\u503c\u3002\u8be5\u5b57\u6bb5\u76ee\u524d\u53ea\u80fd\u53d6\u503c0\u30011\u62162\u7684\u5e42\u3002\u5f53\u503c\u4e3a0\u62161\u65f6\uff0c\u8868\u660e\u8be5\u8282\u7684\u5730\u5740\u4e0d\u7528\u5bf9\u9f50\uff0c\u5426\u5219\u5219\u9700\u8981\u5411\u8fd9\u4e2a\u5b57\u6bb5\u7684\u503c\u5bf9\u9f50\u3002sh_addr\u7684\u503c\u5fc5\u987b\u5411\u8fd9\u4e2a\u5b57\u6bb5\u5bf9\u9f50\uff0c\u5373\u53ef\u4ee5\u88ab\u8fd9\u4e2a\u5b57\u6bb5\u6574\u9664\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>sh_entsize<\/td>\n<td>\u5982\u679c\u8282\u533a\u4e2d\u5305\u542b\u7c7b\u4f3c\u8868\u683c\u7684\u5927\u5c0f\u56fa\u5b9a\u7684\u6570\u636e\u9879\u76ee\uff0c\u8be5\u5b57\u6bb5\u5b58\u50a8\u4e86\u8868\u9879\u7684\u5927\u5c0f\uff1b\u5982\u679c\u4e0d\u5b58\u5728\u8fd9\u6837\u7684\u5b57\u6bb5\uff0c\u5219\u8be5\u5b57\u6bb5\u4e3a0\u3002<\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>SHT\u76840\u53f7\u9879\u4e5f\u662f\u5b58\u5728\u7684\uff0c\u4f46\u662f\u5176\u662f\u4e00\u4e2a\u7a7a\u7684\u8868\u9879\uff08\u6240\u4ee5sh_link\u4e3a0\u7684\u8868\u9879\u5b9e\u9645\u4e0a\u5c31\u662f\u65e0\u5173\u8054\u800c\u8282\uff09\uff0c\u5e76\u4e0d\u5177\u6709\u5b9e\u9645\u5185\u5bb9\uff0c\u5728\u6587\u4ef6\u4e2d\u7684\u5185\u5bb9\u4e5f\u662f\u56fa\u5b9a\u7684\uff0c\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u540d\u5b57<\/th>\n<th>\u503c<\/th>\n<th>\u610f\u4e49<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>sh_name<\/td>\n<td>0<\/td>\n<td>\u65e0\u540d\u5b57<\/td>\n<\/tr>\n<tr>\n<td>sh_type<\/td>\n<td>SHT_NULL<\/td>\n<td>\u975e\u6d3b\u52a8\u7c7b\u578b<\/td>\n<\/tr>\n<tr>\n<td>sh_flags<\/td>\n<td>0<\/td>\n<td>\u65e0\u6807\u5fd7<\/td>\n<\/tr>\n<tr>\n<td>sh_addr<\/td>\n<td>0<\/td>\n<td>\u65e0\u5730\u5740<\/td>\n<\/tr>\n<tr>\n<td>sh_offset<\/td>\n<td>0<\/td>\n<td>\u65e0\u6587\u4ef6\u5185\u504f\u79fb\u91cf<\/td>\n<\/tr>\n<tr>\n<td>sh_size<\/td>\n<td>0<\/td>\n<td>\u65e0\u5927\u5c0f<\/td>\n<\/tr>\n<tr>\n<td>sh_link<\/td>\n<td>SHN_UNDEF<\/td>\n<td>\u65e0\u8282\u5934\u8868\u5bf9\u5e94\u9879<\/td>\n<\/tr>\n<tr>\n<td>sh_info<\/td>\n<td>0<\/td>\n<td>\u65e0\u9644\u52a0\u4fe1\u606f<\/td>\n<\/tr>\n<tr>\n<td>sh_addralign<\/td>\n<td>0<\/td>\n<td>\u65e0\u5bf9\u9f50\u683c\u5f0f<\/td>\n<\/tr>\n<tr>\n<td>sh_entsize<\/td>\n<td>0<\/td>\n<td>\u65e0\u8868\u9879\u5927\u5c0f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>3.2 sh_type<\/h2>\n<p>sh_type\u5b57\u6bb5\u662felf\u8282\u533a\u7684\u79cd\u7c7b\uff0c\u5176\u79cd\u7c7b\u548c\u76f8\u5173\u8282\u533a\u53ca\u8bf4\u660e\u89c1\u4e0b\u8868\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th><strong>\u7c7b\u578b\u540d\u79f0<\/strong><\/th>\n<th><strong>\u5e38\u89c1\u8282\u533a\u540d\u79f0<\/strong><\/th>\n<th><strong>\u53d6\u503c<\/strong><\/th>\n<th><strong>\u8bf4\u660e<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>SHT_NULL<\/td>\n<td>\u2013<\/td>\n<td>0<\/td>\n<td>\u65e0\u5b9e\u9645\u5185\u5bb9\u7684\u8282\u533a\uff0c\u5982\u4e0a\u6587\u4ecb\u7ecd\u76840\u53f7\u8282\u533a\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_PROGBITS<\/td>\n<td>.comments<br \/>.data<br \/>.data1<br \/>.debug<br \/>.fini<br \/>.got<br \/>.init<br \/>.interp<br \/>.line<br \/>.pit<br \/>.rodata<br \/>.rodata1<br \/>.text<\/td>\n<td>1<\/td>\n<td>\u6b64\u8282\u533a\u5305\u542b\u7a0b\u5e8f\u9700\u8981\u7684\u5404\u79cd\u6570\u636e\uff0c\u4f8b\u5982\u4ee3\u7801\u3001\u53d8\u91cf\u7b49\uff0c\u5176\u683c\u5f0f\u548c\u542b\u4e49\u90fd\u7531\u7a0b\u5e8f\u6765\u89e3\u91ca\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_SYMTAB\/SHT_DYNSYM<\/td>\n<td>.dynstr <br \/>.symtab<\/td>\n<td>2(11)<\/td>\n<td>\u8fd9\u4e24\u79cd\u8282\u533a\u90fd\u5305\u542b\u7b26\u53f7\u8868\uff0c\u5176\u4e2dSHT_DYNSYM\u4e3a\u52a8\u6001\u94fe\u63a5\u7b26\u53f7\u8868<\/td>\n<\/tr>\n<tr>\n<td>SHT_STRTAB<\/td>\n<td>.shstrtab<\/td>\n<td>3<\/td>\n<td>\u6b64\u8282\u533a\u5305\u542b\u5b57\u7b26\u4e32\u8868\u3002\u76ee\u6807\u6587\u4ef6\u53ef\u80fd\u5305\u542b\u591a\u4e2a\u5b57\u7b26\u4e32\u8868\u8282\u533a\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_RELA<\/td>\n<td>.relaname<\/td>\n<td>4<\/td>\n<td>\u5b58\u653e\u91cd\u5b9a\u4f4d\u504f\u79fb\u4fe1\u606f\u7684\u8282\u533a<\/td>\n<\/tr>\n<tr>\n<td>SHT_HASH<\/td>\n<td>.hash<\/td>\n<td>5<\/td>\n<td>\u6b64\u8282\u533a\u5305\u542b\u7b26\u53f7\u5bf9\u5e94\u7684\u54c8\u5e0c\u8868\uff0c\u4e3b\u8981\u7528\u4e8e\u5feb\u901f\u68c0\u7d22\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_DYNAMIC<\/td>\n<td>.dynamic<\/td>\n<td>6<\/td>\n<td>\u6b64\u8282\u533a\u5305\u542b\u52a8\u6001\u94fe\u63a5\u7684\u4fe1\u606f\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_NOTE<\/td>\n<td>.note<\/td>\n<td>7<\/td>\n<td>\u6b64\u8282\u533a\u5305\u542b\u4ee5\u67d0\u79cd\u65b9\u5f0f\u6765\u6807\u8bb0\u6587\u4ef6\u7684\u4fe1\u606f\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_NOBITS<\/td>\n<td>.bss<\/td>\n<td>8<\/td>\n<td>\u8fd9\u79cd\u7c7b\u578b\u7684\u8282\u533a\u4e0d\u5360\u7528\u6587\u4ef6\u4e2d\u7684\u7a7a\u95f4\uff0c\u4f46\u662f\u4ecd\u7136\u5177\u6709offset\u7b49\u5b57\u6bb5\uff0c \u5176\u5f80\u5f80\u53ea\u4ee3\u8868\u903b\u8f91\u4e0a\u7684\u4f4d\u7f6e\u3002\u5176\u4ed6\u65b9\u9762\u548cSHT_PROGBITS \u76f8\u4f3c\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_REL<\/td>\n<td>.relname<\/td>\n<td>9<\/td>\n<td>\u8be5\u5b57\u8282\u5305\u542b\u4e86\u91cd\u5b9a\u4f4d\u4fe1\u606f<\/td>\n<\/tr>\n<tr>\n<td>SHT_SHLIB<\/td>\n<td><\/td>\n<td>10<\/td>\n<td>\u6b64\u8282\u533a\u88ab\u4fdd\u7559\uff0c\u4e0d\u8fc7\u5176\u8bed\u4e49\u662f\u672a\u89c4\u5b9a\u7684\u3002\u5305\u542b\u6b64\u7c7b\u578b\u8282\u533a\u7684\u7a0b\u5e8f\u4e0e ABI \u4e0d\u517c\u5bb9\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_LOPROC<\/td>\n<td><\/td>\n<td>0X70000000<\/td>\n<td>\u8fd9\u4e00\u6bb5\uff08\u5305\u62ec\u4e24\u4e2a\u8fb9\u754c\uff09\uff0c\u662f\u4fdd\u7559\u7ed9\u5904\u7406\u5668\u4e13\u7528\u8bed\u4e49\u7684\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_HIPROC<\/td>\n<td><\/td>\n<td>OX7FFFFFFF<\/td>\n<td>\u8fd9\u4e00\u6bb5\uff08\u5305\u62ec\u4e24\u4e2a\u8fb9\u754c\uff09\uff0c\u662f\u4fdd\u7559\u7ed9\u5904\u7406\u5668\u4e13\u7528\u8bed\u4e49\u7684\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_LOUSER<\/td>\n<td><\/td>\n<td>0X80000000<\/td>\n<td>\u6b64\u503c\u7ed9\u51fa\u4fdd\u7559\u7ed9\u5e94\u7528\u7a0b\u5e8f\u7684\u7d22\u5f15\u4e0b\u754c\u3002<\/td>\n<\/tr>\n<tr>\n<td>SHT_HIUSER<\/td>\n<td><\/td>\n<td>0X8FFFFFFF<\/td>\n<td>\u6b64\u503c\u7ed9\u51fa\u4fdd\u7559\u7ed9\u5e94\u7528\u7a0b\u5e8f\u7684\u7d22\u5f15\u4e0a\u754c\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>3.3 \u4e0d\u540c\u7c7b\u578b\u8282\u533a\u7684\u6570\u636e\u7ed3\u6784<\/h2>\n<p>\u4e0d\u540c\u7c7b\u578b\u7684\u8282\u533a\uff0c\u5176\u6570\u636e\u7684\u6570\u636e\u7ed3\u6784\u4e5f\u90fd\u4e0d\u76f8\u540c\u3002\u5176\u6570\u636e\u5927\u4f53\u5206\u4e3a\u4e24\u79cd\uff0c\u4e00\u79cd\u662f\u9700\u8981\u88ab\u52a0\u8f7d\u5668\u8fdb\u884c\u89e3\u6790\uff0c\u7ed9\u52a0\u8f7d\u8fc7\u7a0b\u63d0\u4f9b\u8f85\u52a9\u4fe1\u606f\uff1b\u53e6\u4e00\u79cd\u5c31\u662f\u7a0b\u5e8f\u4ee3\u7801\u548c\u6570\u636e\uff0c\u52a0\u8f7d\u5668\u76f4\u63a5\u5c06\u5176 copy \u5230\u5bf9\u5e94\u7684\u865a\u62df\u5730\u5740\u5373\u53ef\uff0c\u4e8c\u8fdb\u5236\u4ee3\u7801\u548c\u6570\u636e\u7531 CPU \u6267\u884c\u3002<\/p>\n<h3>3.3.1 SHT_SYMTAB<\/h3>\n<p>\u8be5\u7c7b\u578b\u7684\u8282\u533a\u5b58\u653e\u7684\u6570\u636e\u4e3a\u7b26\u53f7\u8868\uff0c\u5176\u4e3a\u4e00\u4e2a\u6570\u7ec4\uff0c\u6570\u7ec4\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20\u4e3a\u4e00\u4e2a\u7528\u4e8e\u63cf\u8ff0\u7b26\u53f7\u7684\u7ed3\u6784\u4f53\uff0c\u5176\u5b9a\u4e49\u5982\u4e0b\uff08\u4ee532\u4f4d\u4e3a\u4f8b\uff09\uff1a<\/p>\n<pre><code class=\"language-cpp\">typedef struct\n{\n  Elf32_Word    st_name;        \/* Symbol name (string tbl index) *\/\n  Elf32_Addr    st_value;       \/* Symbol value *\/\n  Elf32_Word    st_size;        \/* Symbol size *\/\n  unsigned char st_info;        \/* Symbol type and binding *\/\n  unsigned char st_other;       \/* Symbol visibility *\/\n  Elf32_Section st_shndx;       \/* Section index *\/\n} Elf32_Sym;<\/code><\/pre>\n<p>\u5404\u5b57\u6bb5\u548c\u5176\u542b\u4e49\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u540d\u79f0<\/th>\n<th>\u542b\u4e49<\/th>\n<th>\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>st_name<\/td>\n<td>\u7b26\u53f7\u7684\u540d\u79f0\uff0c\u8be5\u7b26\u53f7\u540d\u79f0\u5728\u5b57\u7b26\u4e32\u8868\uff08\u5373strtab\uff09\u4e2d\u7684\u504f\u79fb<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>st_value<\/td>\n<td>\u7b26\u53f7\u7684\u53d6\u503c\uff0c\u5373\u8be5\u7b26\u53f7\u6240\u5bf9\u5e94\u7684\u504f\u79fb\u503c\u3002<\/td>\n<td>\u5bf9\u4e8e\u7b26\u53f7_start\u6765\u8bf4\uff0c\u5176st_value\u503c\u5c31\u7b49\u4e8e\u7a0b\u5e8f\u7684\u5165\u53e3\u5730\u5740\uff0c\u800c\u5bf9\u4e8e\u4e00\u4e2a\u53d8\u91cf\u7b26\u53f7\u6765\u8bf4\uff0c\u5176\u503c\u5c31\u7b49\u4e8e\u8fd9\u4e2a\u53d8\u91cf\u7684\u6307\u9488<\/td>\n<\/tr>\n<tr>\n<td>st_size<\/td>\n<td>\u7b26\u53f7\u6240\u5360\u7528\u7684\u5927\u5c0f\u3002\u800c\u5bf9\u4e8e\u51fd\u6570\u6765\u8bf4\uff0c\u5176\u7b26\u53f7\u5360\u7528\u7684\u4e3a\u51fd\u6570\u7684\u5927\u5c0f\u3002<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>st_info<\/td>\n<td>\u7b26\u53f7\u7684\u7c7b\u578b\u548c\u7ed1\u5b9a\u5c5e\u6027\u3002\u8be5\u5b57\u8282\u7684\u9ad8\u56db\u4f4d\u7528\u4e8e\u63cf\u8ff0\u7ed1\u5b9a\u4fe1\u606f\uff0c\u4f4e\u56db\u4f4d\u8868\u793a\u7c7b\u578b\u3002<\/td>\n<td>\u5176\u7c7b\u578b\u5982\u4e0b\uff1a <br \/>\u5b8f\u5b9a\u4e49 \u53d6\u503c \u542b\u4e49 <br \/>STT_NOTYPE 0 \u672a\u6307\u5b9a\u7c7b\u578b. <br \/>STT_OBJECT 1 \u8be5\u7b26\u53f7\u662f\u4e00\u4e2a\u6570\u636e\u5bf9\u8c61 <br \/>STT_FUNC 2 \u8be5\u7b26\u53f7\u662f\u4e00\u4e2a\u4ee3\u7801\u5bf9\u8c61\uff0c\u867d\u7136\u540d\u79f0\u4e3a FUNC\uff0c\u4f46\u662f\u5b83\u4e5f\u53ef\u4ee5\u662f\u6c47\u7f16\u4ee3\u7801\u4e2d\u7684\u6807\u53f7\uff0c\u6bd4\u5982 _start\uff0c\u6240\u4ee5\u7528\u4ee3\u7801\u5bf9\u8c61\u63cf\u8ff0\u66f4\u5408\u9002 <br \/>STT_SECTION 3 \u4e0e section \u76f8\u5173\u8054\u7684\u7b26\u53f7 <br \/>STT_FILE 4 \u8be5\u7b26\u53f7\u662f\u6587\u4ef6\u540d <br \/>STT_COMMON 5 \u901a\u5e38\u662f weak \u7c7b\u578b\u7684\u7b26\u53f7(\u6bd4\u5982\u76ee\u6807\u6587\u4ef6\u4e2d\u672a\u521d\u59cb\u5316\u7684\u5168\u5c40\u53d8\u91cf) <br \/>STT_TLS 6 \u7ebf\u7a0b\u7684\u672c\u5730\u6570\u636e <br \/>STT_RELC 8 \u590d\u6742\u7684\u91cd\u5b9a\u4f4d\u8868\u8fbe\u5f0f  <\/p>\n<p>\u5176\u7ed1\u5b9a\u72b6\u6001\u5982\u4e0b\uff1a <br \/>\u5b8f\u5b9a\u4e49 \u53d6\u503c \u542b\u4e49 <br \/>STB_LOCAL 0 \u5185\u90e8\u7b26\u53f7\uff0c\u5916\u90e8\u4e0d\u53ef\u89c1 <br \/>STB_GLOBAL 1 \u5168\u5c40\u7b26\u53f7 <br \/>STB_WEAK 2 \u548c\u5168\u5c40\u53d8\u91cf\u4e00\u6837\uff0c\u4f18\u5148\u7ea7\u8f83\u4f4e<\/td>\n<\/tr>\n<tr>\n<td>st_other<\/td>\n<td>\u65e0\u610f\u4e49<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>st_shndx<\/td>\n<td>\u76f8\u5173\u8054\u7684 section \u7d22\u5f15\u3002\u6bd4\u5982 main \u51fd\u6570\u5bf9\u5e94\u7684 section \u4e3a .text\uff0c\u6240\u4ee5\u8be5\u5b57\u6bb5\u5c31\u662f .text \u7684\u7d22\u5f15\u3002<\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5176\u7ed1\u5b9a\u72b6\u6001\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u5b8f\u5b9a\u4e49<\/th>\n<th>\u53d6\u503c<\/th>\n<th>\u542b\u4e49<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>STB_LOCAL<\/td>\n<td>0<\/td>\n<td>\u5185\u90e8\u7b26\u53f7\uff0c\u5916\u90e8\u4e0d\u53ef\u89c1<\/td>\n<\/tr>\n<tr>\n<td>STB_GLOBAL<\/td>\n<td>1<\/td>\n<td>\u5168\u5c40\u7b26\u53f7<\/td>\n<\/tr>\n<tr>\n<td>STB_WEAK<\/td>\n<td>2<\/td>\n<td>\u548c\u5168\u5c40\u53d8\u91cf\u4e00\u6837\uff0c\u4f18\u5148\u7ea7\u8f83\u4f4e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<blockquote>\n<p>\u5bf9\u4e8e\u7b26\u53f7\u8868\uff0c\u867d\u7136\u5176\u5b58\u653e\u7684\u662f\u5730\u5740\uff0c\u4f46\u662f\u5728\u7a0b\u5e8f\u4e2d\uff0c\u5730\u5740\u4f1a\u76f4\u63a5\u88ab\u7f16\u8bd1\u8fdb\u6307\u4ee4\u4e2d\u3002\u6240\u4ee5\u5b9e\u9645\u7a0b\u5e8f\u8fd0\u884c\u7684\u65f6\u5019\u7528\u4e0d\u5230\u7b26\u53f7\u8868\u3002\u7b26\u53f7\u8868\u4e2d\u5b58\u653e\u7684\u5730\u5740\u7684\u4f5c\u7528\u662f\u5728\u94fe\u63a5\u8fc7\u7a0b\u7528\u4e8e\u91cd\u5b9a\u4f4d\uff0c\u5373\u5728\u7b26\u53f7\u6240\u5bf9\u5e94\u503c\u5728\u5185\u5b58\u4e2d\u5730\u5740\u8fd8\u672a\u786e\u5b9a\u7684\u65f6\u5019\u8f85\u52a9\u5176\u786e\u5b9a\u5728\u5185\u5b58\u4e2d\u7684\u5730\u5740\u3002<\/p>\n<\/blockquote>\n<h3>3.3.2 SHT_NOTE<\/h3>\n<p>SHT_NOTE \u7c7b\u578b\u7684\u8282\u533a\u7528\u4e8e\u6807\u8bb0\u6587\u4ef6\u7684\u76f8\u5173\u4fe1\u606f\uff0c\u5c5e\u4e8e\u5728\u52a0\u8f7d\u8fc7\u7a0b\u4e2d\u8d77\u5230\u8f85\u52a9\u4f5c\u7528\u7684\u8282\u533a\u3002\u5176\u6570\u636e\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<pre><code class=\"language-cpp\">typedef struct\n{\n  Elf32_Word n_namesz;          \/* Length of the note&#039;s name.  *\/\n  Elf32_Word n_descsz;          \/* Length of the note&#039;s descriptor.  *\/\n  Elf32_Word n_type;            \/* Type of the note.  *\/\n} Elf32_Nhdr;<\/code><\/pre>\n<p><strong>namesz<\/strong>\uff1aname \u7684\u957f\u5ea6<\/p>\n<p><strong>descsz<\/strong>\uff1adesc \u5373\u63cf\u8ff0\u90e8\u5206\u7684\u957f\u5ea6\u3002<\/p>\n<p><strong>type<\/strong>\uff1a desc \u90e8\u5206\u6570\u636e\u7684\u7c7b\u578b\uff0c\u5373\u5982\u4f55\u89e3\u6790\u5b83\u3002<\/p>\n<p>SHT_NOTE\u7684\u6570\u636e\u90e8\u5206\u957f\u5ea6\u662f\u4e0d\u56fa\u5b9a\u7684\uff0cnamez\u548cdescsz\u5b57\u6bb5\u51b3\u5b9a\u4e86\u5176\u957f\u5ea6\u3002\u56e0\u5176\u6570\u636e\u957f\u5ea6\u4e0d\u5b9a\uff0c\u6240\u4ee5\u6ca1\u6709\u76f4\u63a5\u5c06\u6570\u636e\u5b9a\u4e49\u5728\u7ed3\u6784\u4f53\u4e2d\uff0c\u4e0d\u8fc7\u5728elf\u4e2d\uff0c\u8fd9\u4e2a\u533a\u5757\u7684\u6570\u636e\u5c31\u5b58\u653e\u5728\u4e0a\u8ff0\u4e09\u4e2a\u7ed3\u6784\u4f53\u540e\u3002<\/p>\n<h2>3.4 sh_link \u548c sh_info<\/h2>\n<p>\u8fd9\u4e24\u4e2a\u5b57\u6bb5\u53d7\u5230\u5176\u8282\u533a\u7c7b\u578b\u7684\u5f71\u54cd\uff0c\u542b\u4e49\u4e5f\u4e0d\u540c\uff0c\u5176\u542b\u4e49\u548c\u7c7b\u578b\u5bf9\u7167\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>sh_type<\/th>\n<th>sh_link<\/th>\n<th>sh_info<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>SHT_DYNAMIC<\/td>\n<td>\u6b64\u8282\u533a\u4e2d\u6761\u76ee\u6240\u7528\u5230\u7684\u5b57\u7b26\u4e32\u8868\u683c\u7684\u8282\u533a\u5934\u90e8\u7d22\u5f15<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>SHT_HASH<\/td>\n<td>\u6b64\u54c8\u5e0c\u8868\u6240\u4f7f\u7528\u7684\u7b26\u53f7\u8868\u7684\u8282\u533a\u5934\u90e8\u7d22\u5f15<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>SHT_RELA<\/td>\n<td>\u76f8\u5173\u7b26\u53f7\u8868\u7684\u8282\u533a\u5934\u90e8\u7d22\u5f15<\/td>\n<td>\u91cd\u5b9a\u4f4d\u6240\u9002\u7528\u7684\u8282\u533a\u7684\u8282\u533a\u5934\u90e8\u7d22\u5f15<\/td>\n<\/tr>\n<tr>\n<td>SHT_DYNSYM<\/td>\n<td>\u76f8\u5173\u8054\u7684\u5b57\u7b26\u4e32\u8868\u7684\u8282\u533a\u5934\u90e8\u7d22\u5f15<\/td>\n<td>\u6700\u540e\u4e00\u4e2a\u5c40\u90e8\u7b26\u53f7\uff08\u7ed1\u5b9a STB_LOCAL\uff09\u7684\u7b26\u53f7\u8868\u7d22\u5f15\u503c\u52a0\u4e00<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001\u683c\u5f0f\u6982\u8ff0 1.1 elf\u6587\u4ef6\u7c7b\u578b elf\u6587\u4ef6\u6709\u4e09\u79cd\u7c7b\u578b\uff1a\u53ef\u91cd\u5b9a\u5411\u6587\u4ef6\u3001\u53ef\u6267\u884c\u6587\u4ef6\u548c\u5171\u4eab\u76ee\u6807\u6587\u4ef6 \u9002\u4e8e\u8fde\u63a5\u7684 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":5903,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,2],"tags":[15],"series":[],"class_list":["post-5895","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-so-reverse-engineering","category-study-notes","tag-elf"],"_links":{"self":[{"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/posts\/5895","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/comments?post=5895"}],"version-history":[{"count":11,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/posts\/5895\/revisions"}],"predecessor-version":[{"id":7414,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/posts\/5895\/revisions\/7414"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/media\/5903"}],"wp:attachment":[{"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/media?parent=5895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/categories?post=5895"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/tags?post=5895"},{"taxonomy":"series","embeddable":true,"href":"https:\/\/www.wangonc.com\/index.php\/wp-json\/wp\/v2\/series?post=5895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}