/*

* Copyright (c) 2006-2009 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 DEFAULT_VERSION 2

#define ELFADDR(rtype, p, o) (rtype *)(((char *)p) + o)

FILE *OUTFILE;

void croak(char * s)

{

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

	exit(EXIT_FAILURE);

}

void croak2(char * s1, char * s2)

{

	printf("GENINF ERROR: %s %s\n", s1, s2);

	exit(EXIT_FAILURE);

}

int GetFileSize(FILE * f, char * file)

{

	int r = fseek(f, 0, SEEK_END);

	if (r) croak2("can't seek to end of file:", file);

	r = ftell(f);

	rewind(f);

	return r;

}

void EnsureElf(Elf32_Ehdr* eh)

{

	if (!(eh->e_ident[EI_MAG0] == ELFMAG0 &&

	      eh->e_ident[EI_MAG1] == ELFMAG1 &&

	      eh->e_ident[EI_MAG2] == ELFMAG2 &&

	      eh->e_ident[EI_MAG3] == ELFMAG3)) 

		croak("Invalid ELF magic.\n");

	if (eh->e_ident[EI_CLASS] != ELFCLASS32) 

		croak("File is not a 32 bit ELF object file.\n");

	if (eh->e_ident[EI_DATA] != ELFDATA2LSB) 

		croak("File data encoding is not Little Endian.\n");

  	if (eh->e_machine != EM_ARM) 

		croak("File does not target ARM/THUMB processors.\n");

}

Elf32_Ehdr* OpenElfFile (char* file)

{

	Elf32_Ehdr* eh;

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

	if (!f)

		croak2("can't open file:", file);

	int fsize = GetFileSize(f, file);

	eh = (Elf32_Ehdr*)malloc(fsize);

	if (!eh)

		croak("Out of memory");

	if (fread(eh, fsize, 1, f) != 1)

		croak2("Can't read file", file);

	EnsureElf(eh);

	return eh;

}

typedef struct NameList 

{

	NameList * nl_next;

	char * nl_name;

	unsigned int nl_size;

} NameList;

static NameList * ExportedData = 0;

static NameList * ExportedCode = 0;

//Workaround  for compiler defect(To avoid export of static symbols)

static NameList * LocalSymbols = 0;

NameList* IsPresentInList(char * name, NameList * list)

{

	NameList * e = list;

	while (e) {

		if (!strcmp(name, e->nl_name))

			return e;

		else

			e = e->nl_next;

	}

	return 0;

}

NameList* IsExportedData(char * name) 

{

	return IsPresentInList(name,ExportedData);

}

NameList* IsExportedCode(char * name) 

{

	return IsPresentInList(name,ExportedCode);

}

//Workaround  for compiler defect(To avoid export of local symbols)

NameList* IsLocalSymbol(char * name) 

{

 	return IsPresentInList(name,LocalSymbols);

}

void AddToList(char * name, NameList *& list, unsigned int aSymSz)

{

	NameList * ed = new NameList;

	ed->nl_name = name;

	ed->nl_size = aSymSz;

	ed->nl_next = list;

	list = ed;

}

void AddExportedData(char * name, unsigned int aSymSz)

{

	AddToList(name, ExportedData, aSymSz);

}

void AddExportedCode(char * name, unsigned int aSymSz)

{

	AddToList(name, ExportedCode, aSymSz);

}

//Workaround  for compiler defect(To avoid export of local symbols)

void AddLocalSymbols(char * name)

{

	AddToList(name, LocalSymbols, 0);

}

void InitSymbolsLists(Elf32_Ehdr * eh,Elf32_Shdr * shdr,int shnum)

{

	Elf32_Sym * symtab = 0;

	int nSyms = 0;

	char * strtab = 0;

	int i = 0;

	for (i = 0; (i < shnum); i++) {

		if (shdr[i].sh_type == SHT_SYMTAB) {

			symtab = ELFADDR(Elf32_Sym, eh, shdr[i].sh_offset);

			nSyms = shdr[i].sh_size / shdr[i].sh_entsize;

			strtab = ELFADDR(char, eh, shdr[shdr[i].sh_link].sh_offset);

			break;

		}

	}

	for (i = 0; i < nSyms; i++) {

		if (symtab[i].st_info == ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT)) {

			char * name = ELFADDR(char, strtab, symtab[i].st_name);

			AddExportedData(name, symtab[i].st_size);

		} else if (symtab[i].st_info == ELF32_ST_INFO(STB_GLOBAL, STT_FUNC)) {

			char * name = ELFADDR(char, strtab, symtab[i].st_name);

			AddExportedCode(name, symtab[i].st_size);

		}

		else if (symtab[i].st_info == ELF32_ST_INFO(STB_LOCAL, STT_FUNC) || 

 			symtab[i].st_info == ELF32_ST_INFO(STB_LOCAL, STT_OBJECT)) {

		// Workaround for compiler defect to avoid export of local symbols

 			char * name = ELFADDR(char, strtab, symtab[i].st_name);

 			AddLocalSymbols(name);

 		}

	}

}

#define DIRECTIVE_TAG "#<SYMEDIT>#"

#define DIRECTIVE_TAG_SIZE (sizeof(DIRECTIVE_TAG) - 1)

#define EXPORT_DIRECTIVE "EXPORT "

#define EXPORT_DIRECTIVE_SIZE (sizeof(EXPORT_DIRECTIVE) - 1)

void PrintExportsFromSection(char * section, int size)

{

	if (strncmp(DIRECTIVE_TAG, section, DIRECTIVE_TAG_SIZE) != 0) 

		croak("Unrecognized .directive tag");

	section += (DIRECTIVE_TAG_SIZE + 1);

	size -= (DIRECTIVE_TAG_SIZE + 1);

	// The separator for the following entries is 0x0A (i.e. \n). 

	// We're only interested in lines starting with EXPORT

	char eolchar = '\n';

	NameList* aDataSymbol;

	while (size > 0) {

		char * eolp = (char *)memchr(section, eolchar, size);

		int linelength = (eolp - section) + 1;

		if (!strncmp(EXPORT_DIRECTIVE, section, EXPORT_DIRECTIVE_SIZE)) {

			char * symbol = section + EXPORT_DIRECTIVE_SIZE;

			int symbolsize = linelength - EXPORT_DIRECTIVE_SIZE - 1;

			// null-terminate the string - doesn't matter that we side effect the

			// section since we won't see it again and saves making a copy.

			symbol[symbolsize] = 0;

			if (IsExportedCode(symbol)) {

				fprintf(OUTFILE, " %s\n", symbol);

			} else if ( (aDataSymbol = IsExportedData(symbol)) != 0) {

				fprintf(OUTFILE, " %s DATA %d\n", symbol, aDataSymbol->nl_size);

			}

			else {

				//All those symbols included from static libs that are

				//treated as exported because of the dll_runtime compiler

				//option.Such symbols donot figure out in the symbol table.

				//Hence are handled separately here.

				//Workaround  for compiler defect - To avoid export of local symbols

				if(!IsLocalSymbol(symbol)) 

 				{																	

					fprintf(OUTFILE, " %s\n", symbol);								

				}

			}

		}

		size -= linelength;

		section += linelength;

	}

}

void PrintABIv1ExportSymbols (Elf32_Ehdr * eh)

{

  int shoff = eh->e_shoff;                      // offset of section header table

  if (shoff) {

    Elf32_Shdr * shdr = ELFADDR(Elf32_Shdr, eh, shoff);

    int shnum = eh->e_shnum;                    // number of section headers

	// e_shnum will be 0 if the number of sections is >= SHN_LORESERVE (0xff00)

	// If this is the case, sh_size contains the actual number of section headers.

	// If sh_size is 0, there really aren't any section headers.

	if (!shnum)

		shnum = shdr->sh_size;

    int shstrndx = eh->e_shstrndx;

	// If the section name string table index is >= SHN_LORESERVE (0xff00), shstrndx

	// contains SHN_XINDEX (0xffff).

	// If this is the case, sh_link contains the actual index of the section name string

	// table, otherwise sh_link is 0.

	if (shstrndx >= 65535)

		shstrndx = shdr->sh_link;

	// Initialize list of global data symbols

	InitSymbolsLists(eh,shdr,shnum);

    int snameoffset = shdr[shstrndx].sh_offset; // offset in file of sections' names

    char * sname = ELFADDR(char, eh, snameoffset);

    for (int i = 0; i < shnum; i++) {

      if (i != shstrndx) {

		if (!strcmp(".directive", &sname[shdr[i].sh_name])) {

			// we're in business. print the section to stdout

			char * data = ELFADDR(char, eh, shdr[i].sh_offset);

			int size = shdr[i].sh_size;

			PrintExportsFromSection(data, size);

		}

      }

    }

  }

}

void PrintABIv2ExportSymbols(Elf32_Ehdr *eh)

{

	int shoff = eh->e_shoff;                      // offset of section header table

	if (shoff) {

	Elf32_Shdr * shdr = ELFADDR(Elf32_Shdr, eh, shoff);

	int shnum = eh->e_shnum;                    // number of section headers

	// e_shnum will be 0 if the number of sections is >= SHN_LORESERVE (0xff00)

	// If this is the case, sh_size contains the actual number of section headers.

	// If sh_size is 0, there really aren't any section headers.

	if (!shnum)

		shnum = shdr->sh_size;

	int shstrndx = eh->e_shstrndx;

	// If the section name string table index is >= SHN_LORESERVE (0xff00), shstrndx

	// contains SHN_XINDEX (0xffff).

	// If this is the case, sh_link contains the actual index of the section name string

	// table, otherwise sh_link is 0.

	if (shstrndx >= 65535)

		shstrndx = shdr->sh_link;

	//Get the symbol table

	Elf32_Sym * symtab = 0;

	int nSyms = 0;

	char * strtab = 0;

	int i = 0;

	for (i = 0; (i < shnum); i++) {

		if (shdr[i].sh_type == SHT_DYNSYM) {

			symtab = ELFADDR(Elf32_Sym, eh, shdr[i].sh_offset);

			nSyms = shdr[i].sh_size / shdr[i].sh_entsize;

			strtab = ELFADDR(char, eh, shdr[shdr[i].sh_link].sh_offset);

			break;

		}

	}

	for (i = 0; i < nSyms; i++) {

		if (symtab[i].st_info == ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT)) {

			char * name = ELFADDR(char, strtab, symtab[i].st_name);

			char * CodeSection = ELFADDR(char, eh, shdr[symtab[i].st_shndx].sh_offset);

			Elf32_Word *aLocation = ELFADDR(Elf32_Word, CodeSection, symtab[i].st_value);

			int ordinal = *aLocation;

			fprintf(OUTFILE, "%s %d DATA %d %d\n",name, ordinal, symtab[i].st_size);

		} else if (symtab[i].st_info == ELF32_ST_INFO(STB_GLOBAL, STT_FUNC)) {

			char * name = ELFADDR(char, strtab, symtab[i].st_name);

			char * CodeSection = ELFADDR(char, eh, shdr[symtab[i].st_shndx].sh_offset);

			Elf32_Word *aLocation = ELFADDR(Elf32_Word, CodeSection, symtab[i].st_value);

			int ordinal = *aLocation;

			fprintf(OUTFILE, "%s %d \n",name, ordinal);

		}

	}

	}

}

void PrintSONAME(Elf32_Ehdr *eh)

{

	int shoff = eh->e_shoff;                      // offset of section header table

	if (shoff) {

		Elf32_Shdr * shdr = ELFADDR(Elf32_Shdr, eh, shoff);

		int shnum = eh->e_shnum;                    // number of section headers

		// e_shnum will be 0 if the number of sections is >= SHN_LORESERVE (0xff00)

		// If this is the case, sh_size contains the actual number of section headers.

		// If sh_size is 0, there really aren't any section headers.

		if (!shnum)

			shnum = shdr->sh_size;

		int shstrndx = eh->e_shstrndx;

		char *aSHdrStrTab = ELFADDR(char, eh, shdr[shstrndx].sh_offset);

		int i;

		Elf32_Verdef *aVerDef = 0;

		char *aStringTab = 0;

		for(i = 0; i < shnum; i++) {

			if(strcmp(aSHdrStrTab + shdr[i].sh_name, ".version_d") == 0) {

				aVerDef = ELFADDR(Elf32_Verdef,eh , shdr[i].sh_offset );

				aStringTab = ELFADDR(char, eh, shdr[shdr[i].sh_link].sh_offset);

				break;

			}

		}

		if(!aVerDef)

			return;

		char *aLinkAsName;

		while(aVerDef) {

			if(aVerDef->vd_ndx == DEFAULT_VERSION){

				Elf32_Verdaux *aVerAux = ELFADDR(Elf32_Verdaux, aVerDef, aVerDef->vd_aux);

				aLinkAsName = ELFADDR(char, aStringTab, aVerAux->vda_name);

				fprintf(OUTFILE, "%s \n", aLinkAsName);

				break;

			}

			aVerDef = ELFADDR(Elf32_Verdef, aVerDef, aVerDef->vd_next);

		}

	}

}

int main(int argc, char** argv)

{

	if( argc < 2 )

	{

		return EXIT_FAILURE;

	}

	char* file = argv[argc - 1];//The last arg is the file name

	int idx = 0;

	bool outFileOpt = false;

	bool proxyDso = false;

	bool soname = false;

	while(idx < argc )

	{

		if((stricmp(argv[idx], "-o") == 0) && ((idx + 1) < argc) )

		{

			idx++;

			char *outfilename = argv[idx];

			OUTFILE = fopen(outfilename, "wb");

			outFileOpt = true;

		}

		else if(stricmp(argv[idx], "-d") == 0)

		{

			proxyDso = true;

		}

		else if(stricmp(argv[idx], "-s") == 0)

		{

			soname = true;

		}

		idx++;

	}

	if(!outFileOpt)

	{

		OUTFILE = stdout;

	}

	Elf32_Ehdr * eh = OpenElfFile(file);

	if( soname ) {

		PrintSONAME(eh);

	}

	else if( !proxyDso ) {

		PrintABIv1ExportSymbols(eh);

	}

	else {

		PrintABIv2ExportSymbols(eh);

	}

	return EXIT_SUCCESS;

}