los_ld_elf_pri.h

/*
 * Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
 * Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 *    of conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _LOS_LD_ELH_PRI_H
#define _LOS_LD_ELH_PRI_H

#include "los_base.h"

#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */

/* Elf header */
#define LD_EI_NIDENT           16
/* 举例: shell elf 
root@5e3abe332c5a:/home/harmony/out/hispark_aries/ipcamera_hispark_aries/bin# readelf -h shell
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              DYN (Shared object file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x1000
  Start of program headers:          52 (bytes into file)
  Start of section headers:          25268 (bytes into file)
  Flags:                             0x5000200, Version5 EABI, soft-float ABI
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         11
  Size of section headers:           40 (bytes)
  Number of section headers:         27
  Section header string table index: 26
*/
typedef struct {
    UINT8       elfIdent[LD_EI_NIDENT]; /* Magic number and other info *///含前16个字节,又可细分成class、data、version等字段,具体含义不用太关心,只需知道前4个字节点包含`ELF`关键字,这样可以判断当前文件是否是ELF格式
    UINT16      elfType;                /* Object file type *///表示具体ELF类型,可重定位文件/可执行文件/共享库文件
    UINT16      elfMachine;             /* Architecture *///表示cpu架构
    UINT32      elfVersion;             /* Object file version *///表示文件版本号
    UINT32      elfEntry;               /* Entry point virtual address *///对应`Entry point address`,程序入口函数地址,通过进程虚拟地址空间地址表达
    UINT32      elfPhoff;               /* Program header table file offset *///对应`Start of program headers`,表示program header table在文件内的偏移位置
    UINT32      elfShoff;               /* Section header table file offset *///对应`Start of section headers`,表示section header table在文件内的偏移位置
    UINT32      elfFlags;               /* Processor-specific flags *///表示与CPU处理器架构相关的信息
    UINT16      elfHeadSize;            /* ELF header size in bytes *///对应`Size of this header`,表示本ELF header自身的长度
    UINT16      elfPhEntSize;           /* Program header table entry size *///对应`Size of program headers`,表示program header table中每个元素的大小
    UINT16      elfPhNum;               /* Program header table entry count *///对应`Number of program headers`,表示program header table中元素个数
    UINT16      elfShEntSize;           /* Section header table entry size *///对应`Size of section headers`,表示section header table中每个元素的大小
    UINT16      elfShNum;               /* Section header table entry count *///对应`Number of section headers`,表示section header table中元素的个数
    UINT16      elfShStrIndex;          /* Section header string table index *///对应`Section header string table index`,表示描述各section字符名称的string table在section header table中的下标
} LDElf32Ehdr;


typedef struct {
    UINT8       elfIdent[LD_EI_NIDENT]; /* Magic number and other info */
    UINT16      elfType;                /* Object file type */
    UINT16      elfMachine;             /* Architecture */
    UINT32      elfVersion;             /* Object file version */
    UINT64      elfEntry;               /* Entry point virtual address */
    UINT64      elfPhoff;               /* Program header table file offset */
    UINT64      elfShoff;               /* Section header table file offset */
    UINT32      elfFlags;               /* Processor-specific flags */
    UINT16      elfHeadSize;            /* ELF header size in bytes */
    UINT16      elfPhEntSize;           /* Program header table entry size */
    UINT16      elfPhNum;               /* Program header table entry count */
    UINT16      elfShEntSize;           /* Section header table entry size */
    UINT16      elfShNum;               /* Section header table entry count */
    UINT16      elfShStrIndex;          /* Section header string table index */
} LDElf64Ehdr;

#ifdef LOSCFG_AARCH64
#define LD_ELF_EHDR            LDElf64Ehdr
#else
#define LD_ELF_EHDR            LDElf32Ehdr
#endif

/* e_ident[] values */
#define LD_EI_MAG0             0
#define LD_EI_MAG1             1
#define LD_EI_MAG2             2
#define LD_EI_MAG3             3
#define LD_EI_CLASS            4
#define LD_EI_DATA             5
#define LD_EI_VERSION          6
#define LD_EI_PAD              7

#define LD_ELFMAG0             0x7f
#define LD_ELFMAG1             'E'
#define LD_ELFMAG2             'L'
#define LD_ELFMAG3             'F'
#define LD_ELFMAG              "\177ELF"
#define LD_SELFMAG             4

/* EI_CLASS */
#define LD_ELF_CLASS_NONE      0
#define LD_ELF_CLASS32         1
#define LD_ELF_CLASS64         2

#ifdef LOSCFG_AARCH64
#define LD_ELF_CLASS LD_ELF_CLASS64
#else
#define LD_ELF_CLASS LD_ELF_CLASS32
#endif

/* EI_DATA */
#define LD_ELF_DATA_NONE       0
#define LD_ELF_DATA2LSB        1
#define LD_ELF_DATA2MSB        2

/* e_type */
#define LD_ET_NONE             0	//未知文件类型
#define LD_ET_REL              1	//可重定向文件(Relocatable file)：文件保存着代码和适当的数据,用来和其他的目标文件一起来创建一个可执行文件或者是一个共享目标文件.
#define LD_ET_EXEC             2	//可执行文件(Executable file)：文件保存着一个用来执行的程序.（例如bash,gcc等）
#define LD_ET_DYN              3	//共享目标文件, https://my.oschina.net/weharmony/blog/5055124     例如: ./bin/weharmony 
#define LD_ET_CORE             4	//Core文件
#define LD_ET_LOPROC           0xff00	//特定处理器文件扩展下边界
#define LD_ET_HIPROC           0xffff	//特定处理器文件扩展上边界
//ET_LOPROC ~ ET_HIPROC (0xff00 ~ 0xffff)这一范围内的文件类型是为特定处理器而保留的,如果需要为某种处理器专门设定文件格式,可以从这一范围内选取一个做为标识.
/* e_machine */		//处理器体系结构
#define LD_EM_NONE             0     /* No machine */				//未知体系结构
#define LD_EM_M32              1     /* AT&T WE 32100 */			//AT&T WE 32100
#define LD_EM_SPARC            2     /* SPARC */					//SPARC
#define LD_EM_386              3     /* Intel 80386 */				//Intel Architecture
#define LD_EM_68K              4     /* Motorola 68000 */			//Motorola 68000
#define LD_EM_88K              5     /* Motorola 88000 */			//Motorola 88000
#define LD_EM_486              6     /* Intel 80486 */				//Intel 80486
#define LD_EM_860              7     /* Intel 80860 */				//Intel 80486
#define LD_EM_MIPS             8     /* MIPS RS3000 Big-Endian */
#define LD_EM_MIPS_RS4_BE      10    /* MIPS RS4000 Big-Endian */
#define LD_EM_PPC_OLD          17    /* PowerPC - old */
#define LD_EM_PPC              20    /* PowerPC */
#define LD_EM_RCE_OLD          25    /* RCE - old */
#define LD_EM_RCE              39    /* RCE */
#define LD_EM_MCORE            39    /* MCORE */
#define LD_EM_SH               42    /* SH */
#define LD_EM_M32R             36929 /* M32R */
#define LD_EM_NEC              36992 /* NEC 850 series */
#define LD_EM_NEC_830          36    /* NEC 830 series */
#define LD_EM_SC               58    /* SC */
#define LD_EM_ARM              40    /* ARM  */						//目前支持的方式
#define LD_EM_XTENSA           0x5E  /* XTENSA */
#define LD_EM_AARCH64          183   /* ARM AARCH64 */

#ifdef LOSCFG_AARCH64
#define  LD_EM_TYPE  LD_EM_AARCH64
#else
#define  LD_EM_TYPE  LD_EM_ARM
#endif

/* e_flags */	//此字段含有处理器特定的标志位.
#define LD_EF_PPC_EMB          0x80000000

#define LD_EF_MIPS_NOREORDER   0x00000001
#define LD_EF_MIPS_PIC         0x00000002
#define LD_EF_MIPS_CPIC        0x00000004
#define LD_EF_MIPS_ARCH        0xf0000000
#define LD_EF_MIPS_ARCH_MIPS_2 0x10000000
#define LD_EF_MIPS_ARCH_MIPS_3 0x20000000
//段类型
#define LD_PT_NULL             0	//表明本程序头是未使用的,本程序头内的其它成员值均无意义.具有此种类型的程序头应该被忽略.
#define LD_PT_LOAD             1	//此类型表明本程序头指向一个可装载的段.段的内容会被从文件中拷贝到内存中.如前所述,段在文件中的大小是p_filesz,在内存中的大小是p_memsz.如果p_memsz大于p_filesz,在内存中多出的存储空间应填0补充,也就是说,段在内存中可以比在文件中占用空间更大；而相反,p_filesz永远不应该比p_memsz大,因为这样的话,内存中就将无法完整地映射段的内容.在程序头表中,所有PT_LOAD类型的程序头按照p_vaddr的值做升序排列.
#define LD_PT_DYNAMIC          2	//描述了动态加载段
#define LD_PT_INTERP           3	//本段指向了一个以"null"结尾的字符串,这个字符串是一个ELF解析器的路径.这种段类型只对可执行程序有意义,当它出现在共享目标文件中时,是一个无意义的多余项.在一个ELF文件中它最多只能出现一次,而且必须出现在其它可装载段的表项之前
#define LD_PT_NOTE             4	//本段指向了一个以"null"结尾的字符串,这个字符串包含一些附加的信息
#define LD_PT_SHLIB            5	//该段类型是保留的,而且未定义语法.UNIX System V系统上的应用程序不会包含这种表项.
#define LD_PT_PHDR             6	//此类型的程序头如果存在的话,它表明的是其自身所在的程序头表在文件或内存中的位置和大小.这样的段在文件中可以不存在,只有当所在程序头表所覆盖的段只是整个程序的一部分时,才会出现一次这种表项,而且这种表项一定出现在其它可装载段的表项之前.
#define LD_PT_GNU_STACK        0x6474e551

/* e_version and EI_VERSION */
#define LD_EV_NONE             0
#define LD_EV_CURRENT          1

/* Program Header */
typedef struct {
    UINT32 type;     /* Segment type */	//段类型
    UINT32 offset;   /* Segment file offset */		//此数据成员给出本段内容在文件中的位置,即段内容的开始位置相对于文件开头的偏移量.
    UINT32 vAddr;    /* Segment virtual address */	//此数据成员给出本段内容的开始位置在进程空间中的虚拟地址.
    UINT32 phyAddr;  /* Segment physical address */	//此数据成员给出本段内容的开始位置在进程空间中的物理地址.对于目前大多数现代操作系统而言,应用程序中段的物理地址事先是不可知的,所以目前这个成员多数情况下保留不用,或者被操作系统改作它用.
    UINT32 fileSize; /* Segment size in file */		//此数据成员给出本段内容在文件中的大小,单位是字节,可以是0.
    UINT32 memSize;  /* Segment size in memory */	//此数据成员给出本段内容在内容镜像中的大小,单位是字节,可以是0.
    UINT32 flags;    /* Segment flags */			//此数据成员给出了本段内容的属性.
    UINT32 align;    /* Segment alignment */		//对于可装载的段来说,其p_vaddr和p_offset的值至少要向内存页面大小对齐.
} LDElf32Phdr;

typedef struct {
    UINT32 type;     /* Segment type */
    UINT32 flags;    /* Segment flags */
    UINT64 offset;   /* Segment file offset */
    UINT64 vAddr;    /* Segment virtual address */
    UINT64 phyAddr;  /* Segment physical address */
    UINT64 fileSize; /* Segment size in file */
    UINT64 memSize;  /* Segment size in memory */
    UINT64 align;    /* Segment alignment */
} LDElf64Phdr;

#ifdef LOSCFG_AARCH64
#define LD_ELF_PHDR            LDElf64Phdr
#else
#define LD_ELF_PHDR            LDElf32Phdr
#endif

/* Special section indexes */
#define LD_SHN_UNDEF           0
#define LD_SHN_LORESERVE       0xff00
#define LD_SHN_LOPROC          0xff00
#define LD_SHN_HIPROC          0xff1f
#define LD_SHN_ABS             0xfff1
#define LD_SHN_COMMON          0xfff2
#define LD_SHN_HIRESERVE       0xffff
#define LD_SHN_GHCOMMON        0xff00

/* Section header */
typedef struct {
    UINT32 shName;      /* Section name (string tbl index) *///表示每个区的名字
    UINT32 shType;      /* Section type *///表示每个区的功能
    UINT32 shFlags;     /* Section flags *///表示每个区的属性
    UINT32 shAddr;      /* Section virtual addr at execution *///表示每个区的进程映射地址
    UINT32 shOffset;    /* Section file offset *///表示文件内偏移
    UINT32 shSize;      /* Section size in bytes *///表示区的大小
    UINT32 shLink;      /* Link to another section *///Link和Info记录不同类型区的相关信息
    UINT32 shInfo;      /* Additional section information *///Link和Info记录不同类型区的相关信息
    UINT32 shAddrAlign; /* Section alignment *///表示区的对齐单位
    UINT32 shEntSize;   /* Entry size if section holds table *///表示区中每个元素的大小(如果该区为一个数组的话,否则该值为0)
} LDElf32Shdr;


typedef struct {
    UINT32 shName;      /* Section name (string tbl index) */
    UINT32 shType;      /* Section type */
    UINT64 shFlags;     /* Section flags */
    UINT64 shAddr;      /* Section virtual addr at execution */
    UINT64 shOffset;    /* Section file offset */
    UINT64 shSize;      /* Section size in bytes */
    UINT32 shLink;      /* Link to another section */
    UINT32 shInfo;      /* Additional section information */
    UINT64 shAddrAlign; /* Section alignment */
    UINT64 shEntSize;   /* Entry size if section holds table */
} LDElf64Shdr;

#ifdef LOSCFG_AARCH64
#define LD_ELF_SHDR            LDElf64Shdr
#else
#define LD_ELF_SHDR            LDElf32Shdr
#endif

/* sh_type */
#define LD_SHT_NULL            0U
#define LD_SHT_PROGBITS        1U
#define LD_SHT_SYMTAB          2U
#define LD_SHT_STRTAB          3U
#define LD_SHT_RELA            4U
#define LD_SHT_HASH            5U
#define LD_SHT_DYNAMIC         6U
#define LD_SHT_NOTE            7U
#define LD_SHT_NOBITS          8U
#define LD_SHT_REL             9U
#define LD_SHT_SHLIB           10U
#define LD_SHT_DYNSYM          11U
#define LD_SHT_COMDAT          12U
#define LD_SHT_LOPROC          0x70000000U
#define LD_SHT_HIPROC          0x7fffffffU
#define LD_SHT_LOUSER          0x80000000U
#define LD_SHT_HIUSER          0xffffffffU

/* sh_flags  */
#define LD_SHF_WRITE           0x1U
#define LD_SHF_ALLOC           0x2U
#define LD_SHF_EXECINSTR       0x4U
#define LD_SHF_MASKPROC        0xf0000000U

/* Symbol table */
typedef struct {
    UINT32 stName;  /* Symbol table name (string tbl index) *///表示符号对应的源码字符串,为对应String Table中的索引
    UINT32 stValue; /* Symbol table value *///表示符号对应的数值
    UINT32 stSize;  /* Symbol table size *///表示符号对应数值的空间占用大小
    UINT8 stInfo;   /* Symbol table type and binding *///表示符号的相关信息 如符号类型(变量符号、函数符号)
    UINT8 stOther;  /* Symbol table visibility */
    UINT16 stShndx; /* Section table index *///表示与该符号相关的区的索引,例如函数符号与对应的代码区相关
} LDElf32Sym;


typedef struct {
    UINT32 stName;  /* Symbol table name (string tbl index) */
    UINT8 stInfo;   /* Symbol table type and binding */
    UINT8 stOther;  /* Symbol table visibility */
    UINT16 stShndx; /* Section table index */
    UINT64 stValue; /* Symbol table value */
    UINT64 stSize;  /* Symbol table size */
} LDElf64Sym;

#ifdef LOSCFG_AARCH64
#define LD_ELF_SYM             LDElf64Sym
#else
#define LD_ELF_SYM             LDElf32Sym
#endif

#define LD_STN_UNDEF           0U

#define LD_STB_LOCAL           0U
#define LD_STB_GLOBAL          1U
#define LD_STB_WEAK            2U
#define LD_STB_LOPROC          13U
#define LD_STB_HIPROC          15U

#define LD_STT_NOTYPE          0U
#define LD_STT_OBJECT          1U
#define LD_STT_FUNC            2U
#define LD_STT_SECTION         3U
#define LD_STT_FILE            4U
#define LD_STT_LOPROC          13U
#define LD_STT_HIPROC          15U
#define LD_STT_THUMB           0x80U

#define LD_ELF_ST_BIND(info) ((info) >> 4) /* Obtain the binding information of the symbol table */
#define LD_ELF_ST_TYPE(info) ((info) & 0xFU) /* Obtain the type of the symbol table */
#define LD_ELF_ST_INFO(bind, type) (((bind) << 4) + ((type) & 0xFU))

/* Dynamic */
typedef struct {
    UINT32 dynTag;  /* Dynamic entry type */
    union {
        UINT32 val; /* Integer value */
        UINT32 ptr; /* Address value */
    } dyn;
} LDElf32Dyn;

typedef struct {
    UINT64 dynTag;  /* Dynamic entry type */
    union {
        UINT64 val; /* Integer value */
        UINT64 ptr; /* Address value */
    } dyn;
} LDElf64Dyn;

#ifdef LOSCFG_AARCH64
#define LD_ELF_DYN             LDElf64Dyn
#else
#define LD_ELF_DYN             LDElf32Dyn
#endif

/* This is the info that is needed to parse the dynamic section of the file */
#define LD_DT_NULL             0
#define LD_DT_NEEDED           1
#define LD_DT_PLTRELSZ         2
#define LD_DT_PLTGOT           3
#define LD_DT_HASH             4
#define LD_DT_STRTAB           5
#define LD_DT_SYMTAB           6
#define LD_DT_RELA             7
#define LD_DT_RELASZ           8
#define LD_DT_RELAENT          9
#define LD_DT_STRSZ            10
#define LD_DT_SYMENT           11
#define LD_DT_INIT             12
#define LD_DT_FINI             13
#define LD_DT_SONAME           14
#define LD_DT_RPATH            15
#define LD_DT_SYMBOLIC         16
#define LD_DT_REL              17
#define LD_DT_RELSZ            18
#define LD_DT_RELENT           19
#define LD_DT_PLTREL           20
#define LD_DT_DEBUG            21
#define LD_DT_TEXTREL          22
#define LD_DT_JMPREL           23
#define LD_DT_ENCODING         32

/* Relocation */
typedef struct {
    UINT32 offset; /* Address */
    UINT32 info;   /* Relocation type and symbol index */
} LDElf32Rel;

typedef struct {
    UINT32 offset; /* Address */
    UINT32 info;   /* Relocation type and symbol index */
    INT32 addend;  /* Addend */
} LDElf32Rela;

typedef struct {
    UINT64 offset; /* Address */
    UINT64 info;   /* Relocation type and symbol index */
} LDElf64Rel;

typedef struct {
    UINT64 offset; /* Address */
    UINT64 info;   /* Relocation type and symbol index */
    INT64 addend;  /* Addend */
} LDElf64Rela;

#ifdef LOSCFG_AARCH64
#define LD_ELF_REL             LDElf64Rel
#define LD_ELF_RELA            LDElf64Rela
#else
#define LD_ELF_REL             LDElf32Rel
#define LD_ELF_RELA            LDElf32Rela
#endif

#ifdef LOSCFG_AARCH64
#define LD_ELF_R_SYM(info) ((info) >> 32)
#define LD_ELF_R_TYPE(info) ((info) & 0xFFFFFFFFUL)
#define LD_ELF_R_INFO(sym, type) ((((UINT64)(sym)) << 32) + (type))
#else
#define LD_ELF_R_SYM(info) ((info) >> 8)
#define LD_ELF_R_TYPE(info) ((info) & 0xFFU)
#define LD_ELF_R_INFO(sym, type) (((sym) << 8) + (UINT8)(type))
#endif

#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */

#endif /* _LOS_LD_ELH_PRI_H */