/*

* Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <elfdefs.h>

#define MAXPATHNAMELENGTH 2000

#define MAXSYMBOLLENGTH 2000

#define writef(f, d, n, s) if ( 1 != fwrite(d, n, 1, f)) { croak(s); }

void croak(char * s)

{

  printf("GENSTUB ERROR: %s\n", s);

  exit(EXIT_FAILURE);

}

long codeSectionData [] = 

{

  0xe51ff004,    // LDR      pc,0x4

  0x00000000     // the pointer to the imported code

};

#define COMMENTSTRING "\tAndy's magic stub generator vsn 0.2\n"

char commentSectionData[] = // "\tAndy's magic stub generator vsn 0.2\n"

{ 

  '\t','A','n','d','y','\'','s',' ','m','a','g','i','c',' ',

  's','t','u','b',' ','g','e','n','e','r','a','t','o','r',' ',

  'v','s','n',' ','0','.','2','\n'

};

char directiveSectionData[] = // "#<SYMEDIT>\nIMPORT "

{

  '#','<','S','Y','M','E','D','I','T','>','\n',

  'I','M','P','O','R','T',' '

};

char strtabSectionData [] =

{

  0,'$','a',0,                                                          // $a

  '$','d',0,                                                            // $d

  'S','t','u','b','C','o','d','e',0,                                    // StubCode

  '.','d','i','r','e','c','t','i','v','e',0,                            // .directive

  't','h','e','I','m','p','o','r','t','e','d','S','y','m','b','o','l',0 // theImportSymbol

};

Elf32_Sym symtabSectionData[] =

{

  // undefined symbol

  {

    0, // st_name

    0, // st_value

    0, // st_size

    0, // st_info

    0, // st_other

    0  // stshndx

  },

  // $a

  {

    1, // st_name

    0, // st_value

    0, // st_size

    ELF32_ST_INFO(STB_LOCAL,STT_FUNC), // st_info

    0, // st_other

    1  // stshndx

  },

  // $d

  {

    4, // st_name

    4, // st_value

    0, // st_size

    ELF32_ST_INFO(STB_LOCAL,STT_OBJECT), // st_info

    0, // st_other

    1  // stshndx

  },

  // StubCode

  {

    7, // st_name

    0, // st_value

    sizeof(codeSectionData), // st_size

    ELF32_ST_INFO(STB_LOCAL,STT_SECTION), // st_info

    0, // st_other

    1  // stshndx

  },

  // .directive

#define DIRECTIVESYMNDX 4

  {

    16,// st_name

    0, // st_value

    0, // st_size - to be filled on

    ELF32_ST_INFO(STB_LOCAL,STT_SECTION), // st_info

    0, // st_other

    3  // stshndx

  },

  // theImportedSymbol

  {

    27, // st_name

    4, // st_value

    0, // st_size

    ELF32_ST_INFO(STB_LOCAL,STT_FUNC), // st_info

    0, // st_other

    1  // stshndx

  },

  // the exported symbol

#define EXPORTEDSYMBOLSTRNDX 45

  {

    EXPORTEDSYMBOLSTRNDX, // st_name

    0, // st_value

    0, // st_size

    ELF32_ST_INFO(STB_GLOBAL,STT_FUNC), // st_info

    0, // st_other

    1  // stshndx

  },

  // the imported symbol

#define IMPORTEDSYMBOLSYMNDX 7

  {

    0, // st_name - needs to be filled in = EXPORTEDSYMBOLSTRNDX + strlen(exportedSymbol) + 1

    0, // st_value

    0, // st_size

    ELF32_ST_INFO(STB_GLOBAL,STT_NOTYPE), // st_info

    0, // st_other

    SHN_UNDEF  // stshndx

  }

};

Elf32_Rel relocSectionData [] =

{

  {

    0x00000004, // r_offset

    ELF32_R_INFO(IMPORTEDSYMBOLSYMNDX, R_ARM_ABS32)

  }

};

char shstrtabSectionData []= 

{

  0,'S','t','u','b','C','o','d','e',0,                 // StubCode

  '.','r','e','l','S','t','u','b','C','o','d','e',0,   // .relStubCode

  '.','d','i','r','e','c','t','i','v','e',0,           // .directive

  '.','s','y','m','t','a','b',0,                       // .symtab

  '.','s','t','r','t','a','b',0,                       // .strtab

  '.','c','o','m','m','e','n','t',0,                  // .comment

  '.','s','h','s','t','r','t','a','b',0                // .shstrtab

};

Elf32_Shdr SectionHeaderTable[] = 

{

  // dummy section

  {

    0,             // sh_name - to be filled

    SHT_NULL,      // sh_type

    0,             // sh_flags

    0,             // sh_addr

    0,             // sh_offset - file offset of this section - to be filled in

    0,             // sh_size - to be filled in

    0,             // sh_link

    0,             // sh_info

    0,             // sh_addralign

    0              // sh_entsize

  },

  // StubCode section

#define CODEINDEX 1

#define CODEOFFSET (sizeof(Elf32_Ehdr) + (8 * sizeof(Elf32_Shdr)))

#define CODESIZE (sizeof(codeSectionData))

  {

    1,             // sh_name 

    SHT_PROGBITS,  // sh_type

    SHF_ALLOC + SHF_EXECINSTR, // sh_flags

    0,             // sh_addr

    CODEOFFSET,    // sh_offset 

    CODESIZE,      // sh_size

    SHN_UNDEF,     // sh_link

    0,             // sh_info

    4,             // sh_addralign

    0              // sh_entsize

  },

  // relocation data

#define RELOCINDEX 2

#define RELOCOFFSET (CODEOFFSET + CODESIZE)

#define RELOCSIZE (sizeof(relocSectionData))

  {

    10,            // sh_name - to be filled

    SHT_REL,       // sh_type

    0,             // sh_flags

    0,             // sh_addr

    RELOCOFFSET,   // sh_offset - file offset of this section - to be filled in

    RELOCSIZE,     // sh_size - there's only one of them

    3,             // sh_link - index of the symbol table we use

    1,             // sh_info - refers to section 1

    0,             // sh_addralign

    sizeof(Elf32_Rel) // sh_entsize

  },

  // .symtab

#define SYMTABINDEX 3

#define SYMTABOFFSET (RELOCOFFSET + RELOCSIZE)

#define SYMTABSIZE sizeof(symtabSectionData)

{

    34,            // sh_name 

    SHT_SYMTAB,    // sh_type

    0,             // sh_flags

    0,             // sh_addr

    SYMTABOFFSET,  // sh_offset

    SYMTABSIZE, // sh_size

    7,             // sh_link - .strtab - the string table section

    6,             // sh_info - last local symbol

    0,             // sh_addralign

    sizeof(Elf32_Sym)// sh_entsize

  },

  // .comment

#define COMMENTINDEX 4

#define COMMENTOFFSET (SYMTABOFFSET + SYMTABSIZE)

#define COMMENTSIZE (sizeof(commentSectionData))

{

    50,            // sh_name 

    SHT_PROGBITS,  // sh_type

    0,             // sh_flags

    0,             // sh_addr

    COMMENTOFFSET, // sh_offset

    COMMENTSIZE,   // sh_size - to be filled in

    SHN_UNDEF,     // sh_link

    0,             // sh_info

    0,             // sh_addralign

    0              // sh_entsize

  },

  // .shstrtab

#define SHSTRTABINDEX 5

#define SHSTRTABOFFSET (COMMENTOFFSET + COMMENTSIZE)

#define SHSTRTABSIZE sizeof(shstrtabSectionData)

  {

    59,            // sh_name 

    SHT_STRTAB,    // sh_type

    0,             // sh_flags

    0,             // sh_addr

    SHSTRTABOFFSET,// sh_offset

    SHSTRTABSIZE,  // sh_size - to be filled in

    SHN_UNDEF,     // sh_link

    0,             // sh_info

    0,             // sh_addralign

    0              // sh_entsize

      },

  // .directive section

#define DIRECTIVEINDEX 6

#define DIRECTIVEOFFSET SHSTRTABOFFSET + SHSTRTABSIZE

  {

    23,            // sh_name 

    SHT_PROGBITS,  // sh_type

    0,             // sh_flags

    0,             // sh_addr

    DIRECTIVEOFFSET,// sh_offset

    0,             // sh_size - to be filled in

    SHN_UNDEF,     // sh_link 

    0,             // sh_info 

    1,             // sh_addralign

    0              // sh_entsize

  },

  // .strtab

#define STRTABINDEX 7

  {

    42,            // sh_name

    SHT_STRTAB,    // sh_type

    0,             // sh_flags

    0,             // sh_addr

    0,             // sh_offset - to be filled in

    0,             // sh_size - to be filled in

    SHN_UNDEF,     // sh_link

    0,             // sh_info

    0,             // sh_addralign

    0              // sh_entsize

  }

};

#define ELFOBJECTFILEVERSION 1

#define EF_NONE 0x02000000

Elf32_Ehdr headerTemplate = 

{

  {0x7f, 'E', 'L', 'F', 

   ELFCLASS32, ELFDATA2LSB, ELFOBJECTFILEVERSION, 0,

   0, 0, 0, 0,

   0, 0, 0, 0},       // e_ident

  ET_REL,             // e_type

  EM_ARM,             // e_machine

  EV_CURRENT,         // e_version

  0x00000000,         // e_entry

  0,                  // e_phoff

  sizeof(Elf32_Ehdr), // e_shoff

  EF_ARM_EABI_VERSION,// e_flags

  sizeof(Elf32_Ehdr), // e_ehsize

  sizeof(Elf32_Phdr), // e_phentsize

  0,                  // e_phnum

  sizeof(Elf32_Shdr), // e_shentsize

#define SHNUM (sizeof(SectionHeaderTable)/sizeof(Elf32_Shdr))

  SHNUM,              // e_shnum 

  SHSTRTABINDEX       // e_shstrndx

};

void WriteElfHeader(FILE * file);

void WriteSectionHeaderTable(FILE * file);

void WriteCodeSection(FILE * file);

void WriteRelocationSection(FILE * file);

void WriteCommentSection(FILE * file);

void WriteSymtabSection(FILE * file);

void WriteShStrtabSection(FILE * file);

void WriteDirectiveSection(FILE * file, char * import);

void WriteStrtabSection(FILE * file, char * eexport, char * import);

void WriteStubFileX(FILE * file, char * eexport, char * import)

{

  int directiveSize = sizeof(directiveSectionData) + strlen(import) + 1; // terminated by a newline

  int strtabSize = sizeof(strtabSectionData) + strlen(eexport) + strlen(import) + 2; // strings are null terminated

  SectionHeaderTable[DIRECTIVEINDEX].sh_size = directiveSize;

  SectionHeaderTable[STRTABINDEX].sh_offset = DIRECTIVEOFFSET+ directiveSize;

  SectionHeaderTable[STRTABINDEX].sh_size = strtabSize;

  symtabSectionData[IMPORTEDSYMBOLSYMNDX].st_name  = EXPORTEDSYMBOLSTRNDX + strlen(eexport) + 1;

  WriteElfHeader(file);

  WriteSectionHeaderTable(file);

  WriteCodeSection(file);

  WriteRelocationSection(file);

  WriteSymtabSection(file);

  WriteCommentSection(file);

  WriteShStrtabSection(file);

  WriteDirectiveSection(file, import);

  WriteStrtabSection(file, eexport, import);

}

void WriteElfHeader(FILE * file)

{

  writef(file, &headerTemplate, sizeof(headerTemplate), "ELF header");

}

void WriteSectionHeaderTable(FILE * file)

{

  writef(file, &SectionHeaderTable, sizeof(SectionHeaderTable), "Section header table");

}

void CheckFileOffset(FILE * f, int i, char *s)

{

	int o = SectionHeaderTable[i].sh_offset;

	if (ftell(f)!= o) { croak(s); }

}

#define WriteSection(f, i, d, e1, e2) { CheckFileOffset(f, i, e1); writef(f, d, sizeof(d), e2); }

void WriteCodeSection(FILE * file)

{

  WriteSection(file, CODEINDEX, codeSectionData,"StubCode section offset incorrect", "StubCode section");

}

void WriteRelocationSection(FILE * file)

{

  WriteSection(file, RELOCINDEX, relocSectionData,".relStubCode section offset incorrect", ".relStubCode section");

}

void WriteCommentSection(FILE * file)

{

  WriteSection(file, COMMENTINDEX, commentSectionData,".comment section offset incorrect", ".comment section");

}

void WriteSymtabSection(FILE * file)

{

  WriteSection(file, SYMTABINDEX, symtabSectionData,".symtab section offset incorrect", ".symtab section");

}

void WriteShStrtabSection(FILE * file)

{

  WriteSection(file, SHSTRTABINDEX, shstrtabSectionData,".shstrtab section offset incorrect", ".shstrtab section");

}

void WriteDirectiveSection(FILE * file, char * import)

{

  WriteSection(file, DIRECTIVEINDEX, directiveSectionData,

	       ".directive section offset incorrect", ".directive section");

  fprintf(file, "%s\n", import);

}

void WriteStrtabSection(FILE * file, char * eexport, char * import)

{

  char n = 0;

  WriteSection(file, STRTABINDEX, strtabSectionData,".strtab section offset incorrect", ".strtab section");

  fprintf(file, eexport);

  fwrite(&n, sizeof(n), 1, file);

  fprintf(file, import);

  fwrite(&n, sizeof(n), 1, file);

}

void WriteStubFile(char * file, char * eexport, char * import)

{

  FILE * f = fopen(file, "wb");

  if (!f) croak("can't open output file");

  WriteStubFileX(f, eexport, import);

  fclose(f);

}

int  main (void)

{

  char file[MAXPATHNAMELENGTH], eexport[MAXSYMBOLLENGTH], import[MAXSYMBOLLENGTH];

  while (!feof(stdin) && !ferror(stdin)) {

    fscanf(stdin, "%s %s %s\n", file, eexport, import);

    WriteStubFile(file, eexport, import);

  }

  return EXIT_SUCCESS;

}