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/*
Package: dyncall
Library: dynload
File: dynload/dynload_syms_elf.c
Description:
License:
Copyright (c) 2007-2011 Daniel Adler <dadler@uni-goettingen.de>,
Tassilo Philipp <tphilipp@potion-studios.com>,
Olivier Chafik <olivier.chafik@gmail.com>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "../autovar/autovar_OS.h"
/*
dynamic symbol resolver for elf
*/
#include "dynload.h"
#if defined(OS_OpenBSD)
# include <stdint.h>
# include <elf_abi.h>
#elif defined(OS_SunOS)
# include <libelf.h>
#elif defined(OS_BeOS)
# include <elf32.h>
#else
# include <elf.h>
#endif
#if defined(__GLIBC__)
# define _GNU_SOURCE
# define __USE_GNU
#endif
#include "dynload_alloc.h"
#include <assert.h>
#include <fcntl.h>
#include <dlfcn.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
/* run-time configuration 64/32 */
#if defined(OS_OpenBSD)
#else
# include "../autovar/autovar_ABI.h"
# ifdef ABI_ELF64
typedef Elf64_Ehdr Elf_Ehdr;
typedef Elf64_Phdr Elf_Phdr;
typedef Elf64_Shdr Elf_Shdr;
typedef Elf64_Sym Elf_Sym;
# ifndef OS_SunOS
typedef Elf64_Dyn Elf_Dyn;
# endif
typedef Elf64_Sxword Elf_tag;
typedef Elf64_Addr Elf_Addr;
# else
# if defined(OS_BeOS)
typedef struct Elf32_Ehdr Elf_Ehdr;
typedef struct Elf32_Phdr Elf_Phdr;
typedef struct Elf32_Shdr Elf_Shdr;
typedef struct Elf32_Sym Elf_Sym;
typedef struct Elf32_Dyn Elf_Dyn;
typedef Elf32_Sword Elf_tag;
typedef Elf32_Addr Elf_Addr;
# else
typedef Elf32_Ehdr Elf_Ehdr;
typedef Elf32_Phdr Elf_Phdr;
typedef Elf32_Shdr Elf_Shdr;
typedef Elf32_Sym Elf_Sym;
# ifndef OS_SunOS
typedef Elf32_Dyn Elf_Dyn;
# endif
typedef Elf32_Sword Elf_tag;
typedef Elf32_Addr Elf_Addr;
# endif
# endif
#endif
struct DLSyms_
{
const char* pStrTab;
Elf_Sym* pSymTab;
size_t strTabSize;
size_t nSymbols;
Elf_Ehdr* pElf_Ehdr; /* pointer to elf header */
int file; /* fd of lib */
size_t fileSize; /* filesize of open lib */
};
DLSyms* dlSymsInit(const char* libPath)
{
unsigned char* pMem;
void* pSectionContent;
int i;
struct stat st;
Elf_Shdr* pS;
DLSyms* pSyms = (DLSyms*)dlAllocMem(sizeof(DLSyms));
memset(pSyms, 0, sizeof(DLSyms));
pSyms->file = open(libPath, O_RDONLY);
stat(libPath, &st);
pSyms->fileSize = st.st_size;
pSyms->pElf_Ehdr = (Elf_Ehdr*) mmap((void*) NULL, pSyms->fileSize, PROT_READ, MAP_SHARED, pSyms->file, 0);
#ifdef ABI_ELF32
assert(pSyms->pElf_Ehdr->e_ident[EI_CLASS] == ELFCLASS32);
#else
assert(pSyms->pElf_Ehdr->e_ident[EI_CLASS] == ELFCLASS64);
#endif
assert(pSyms->pElf_Ehdr->e_phoff > 0);
assert(pSyms->pElf_Ehdr->e_shoff > 0);
pMem = (unsigned char*)pSyms->pElf_Ehdr;
/* traverse section headers */
pS = (Elf_Shdr*) ( pMem + pSyms->pElf_Ehdr->e_shoff );
/* skip section 0 which is always zero due to the Elf standard. */
for (i = 1; i < pSyms->pElf_Ehdr->e_shnum; i++)
{
Elf_Shdr* pSection = &pS[i];
pSectionContent = ((char*)pMem) + pSection->sh_offset;
switch (pSection->sh_type)
{
case SHT_DYNSYM:
if (!pSyms->pSymTab) {
pSyms->pSymTab = (Elf_Sym*)pSectionContent;
pSyms->nSymbols = pSection->sh_size / pSection->sh_entsize;
}
break;
case SHT_STRTAB:
// Do not trust pSyms->pElf_Ehdr->e_shstrndx!
if (!pSyms->pStrTab) {
pSyms->pStrTab = (const char*)pSectionContent;
pSyms->strTabSize = pSection->sh_size;
}
break;
}
if (pSyms->pSymTab && pSyms->pStrTab)
break;
}
return pSyms;
}
void dlSymsCleanup(DLSyms* pSyms)
{
if(pSyms) {
munmap((void*) pSyms->pElf_Ehdr, pSyms->fileSize);
close(pSyms->file);
dlFreeMem(pSyms);
}
}
int dlSymsCount(DLSyms* pSyms)
{
if (!pSyms)
return 0;
return pSyms->nSymbols;
}
const char* dlSymsName(DLSyms* pSyms, int index)
{
int str_index;
if(!pSyms || !pSyms->pSymTab || index < 0 || index >= pSyms->nSymbols)
return NULL;
str_index = pSyms->pSymTab[index].st_name;
if (str_index < 0 || str_index >= pSyms->strTabSize)
return NULL;
return &pSyms->pStrTab[str_index];
}
const char* dlSymsNameFromValue(DLSyms* pSyms, void* value)
{
Dl_info info;
return (dladdr(value, &info) && (value == info.dli_saddr))
? info.dli_sname
: NULL;
}
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