/
elf.c
1475 lines (1236 loc) · 43.1 KB
/
elf.c
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/* $VER: vlink elf.c V0.14 (29.07.11)
*
* This file is part of vlink, a portable linker for multiple
* object formats.
* Copyright (c) 1997-2011 Frank Wille
*
* vlink is freeware and part of the portable and retargetable ANSI C
* compiler vbcc, copyright (c) 1995-2011 by Volker Barthelmann.
* vlink may be freely redistributed as long as no modifications are
* made and nothing is charged for it. Non-commercial usage is allowed
* without any restrictions.
* EVERY PRODUCT OR PROGRAM DERIVED DIRECTLY FROM MY SOURCE MAY NOT BE
* SOLD COMMERCIALLY WITHOUT PERMISSION FROM THE AUTHOR.
*/
#include "config.h"
#if defined(ELF32) || defined(ELF64)
#define ELF_C
#include "vlink.h"
#include "elfcommon.h"
#include "elf32std.h"
#include "elf64std.h"
/* global data for all ELF targets */
struct StrTabList elfstringlist = { {NULL,NULL,NULL},NULL,STRHTABSIZE,0 };
struct StrTabList elfdstrlist = { {NULL,NULL,NULL},NULL,DYNSTRHTABSIZE,0 };
struct StrTabList elfshstrlist = { {NULL,NULL,NULL},NULL,SHSTRHTABSIZE,0 };
struct SymTabList elfsymlist;
struct SymTabList elfdsymlist;
struct list shdrlist;
struct list elfdynsymlist;
struct Section *elfdynrelocs;
struct Section *elfpltrelocs;
uint32_t elfshdridx,elfsymtabidx,elfshstrtabidx,elfstrtabidx;
uint32_t elfoffset; /* current ELF file offset */
unsigned long elf_file_hdr_gap; /* gap between hdr and first segment */
int8_t elf_endianess = -1; /* used while creating output-file */
/* ELF section names */
const char note_name[] = ".note";
const char dyn_name[] = ".dynamic";
const char hash_name[] = ".hash";
const char dynsym_name[] = ".dynsym";
const char dynstr_name[] = ".dynstr";
const char *dynrel_name[2] = { ".rel.dyn",".rela.dyn" };
const char *pltrel_name[2] = { ".rel.plt",".rela.plt" };
/* local static data */
static struct list phdrlist;
static struct Section *gotsec = NULL;
static struct Section *pltsec = NULL;
static int secsyms; /* offset to find section symbols by shndx */
static char ELFid[4] = { /* identification for all ELF files */
0x7f,'E','L','F'
};
/* table to determine number of buckets in .hash */
static const size_t elf_buckets[] =
{
1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 1031, 2053, 4099, 8209,
16411, 32771, 0
};
/* common linker symbols */
static const char *elf_symnames[] = {
sdabase_name,sda2base_name,"__CTOR_LIST__","__DTOR_LIST__",
gotbase_name+1,pltbase_name+1,dynamic_name+1
};
/*****************************************************************/
/* Read ELF */
/*****************************************************************/
int elf_identify(struct FFFuncs *ff,char *name,void *p,
lword plen,unsigned char class,
unsigned char endian,uint16_t machine,uint32_t ver)
/* check a possible ELF file against the requirements, then */
/* return its type (object, library, shared object) */
{
bool arflag = FALSE;
bool be = (endian == ELFDATA2MSB);
struct Elf_CommonHdr *hdr;
struct ar_info ai;
if (plen < sizeof(struct Elf_CommonHdr))
return ID_UNKNOWN;
if (ar_init(&ai,(char *)p,plen,name)) {
/* library archive detected, extract 1st archive member */
arflag = TRUE;
if (!(ar_extract(&ai))) {
error(38,name); /* Empty archive ignored */
return ID_IGNORE;
}
hdr = (struct Elf_CommonHdr *)ai.data;
}
else
hdr = (struct Elf_CommonHdr *)p;
if ((class==ELFCLASS32 && plen < sizeof(struct Elf32_Ehdr)) ||
(class==ELFCLASS64 && plen < sizeof(struct Elf64_Ehdr)))
return ID_UNKNOWN;
if (!strncmp((char *)hdr->e_ident,ELFid,4)) {
/* ELF identification found */
if (hdr->e_ident[EI_CLASS]==class && hdr->e_ident[EI_DATA]==endian &&
hdr->e_ident[EI_VERSION]==(unsigned char)ver &&
read32(be,hdr->e_version)==ver && read16(be,hdr->e_machine)==machine) {
switch (read16(be,hdr->e_type)) {
case ET_REL:
return arflag ? ID_LIBARCH : ID_OBJECT;
case ET_EXEC:
if (arflag) /* no executables in library archives */
error(40,name,ff->tname);
return ID_EXECUTABLE;
case ET_DYN:
if (arflag) /* no shared objects in library archives */
error(39,name,ff->tname);
return ID_SHAREDOBJ;
default:
error(41,name,ff->tname); /* illegal fmt. / file corrupted */
break;
}
}
}
return ID_UNKNOWN;
}
void elf_check_ar_type(struct FFFuncs *ff,const char *name,void *p,
unsigned char class,unsigned char endian,
uint32_t ver,int nmach,...)
/* check all library archive members before conversion */
{
struct Elf_CommonHdr *ehdr = (struct Elf_CommonHdr *)p;
bool be = (endian == ELFDATA2MSB);
uint16_t m = read16(be,ehdr->e_machine);
va_list vl;
va_start(vl,nmach);
if (!strncmp((char *)ehdr->e_ident,ELFid,4)) {
/* ELF identification found */
if (ehdr->e_ident[EI_CLASS]==class && ehdr->e_ident[EI_DATA]==endian &&
ehdr->e_ident[EI_VERSION]==(unsigned char)ver &&
read32(be,ehdr->e_version)==ver && nmach>0) {
while (nmach--) {
if (va_arg(vl,int) == m)
m = 0;
}
if (m == 0) {
switch (read16(be,ehdr->e_type)) {
case ET_REL:
goto check_ar_exit;
case ET_EXEC: /* no executables in library archives */
error(40,name,ff->tname);
break;
case ET_DYN: /* no shared objects in library archives */
error(39,name,ff->tname);
break;
default: /* illegal fmt. / file corrupted */
break;
}
}
}
}
error(41,name,ff->tname);
check_ar_exit:
va_end(vl);
}
void elf_check_offset(struct LinkFile *lf,char *tabname,void *data,lword size)
{
uint8_t *p = (uint8_t *)data;
if ((p < lf->data) || (p + size) > (lf->data + lf->length))
error(51,lf->pathname,tabname,lf->objname);
}
struct Section *elf_add_section(struct GlobalVars *gv,struct ObjectUnit *ou,
char *name,uint8_t *data,lword size,
uint32_t shtype,uint64_t shflags,uint8_t align)
{
struct LinkFile *lf = ou->lnkfile;
uint8_t type=ST_DATA,flags=0,prot=SP_READ;
if (gv->strip_symbols>=STRIP_DEBUG &&
(!strncmp(name,".debug",6) || !strncmp(name,".line",5) ||
!strncmp(name,".stab",5)))
return NULL; /* ignore debugging sections when -S or -s is given */
if (shtype == SHT_NOBITS) {
data = NULL;
type = ST_UDATA;
flags |= SF_UNINITIALIZED;
}
else {
if (data+size > lf->data+lf->length) /* illegal section offset */
error(49,lf->pathname,name,lf->objname);
}
if ((shflags & SHF_EXECINSTR) && data!=NULL) {
type = ST_CODE;
prot |= SP_EXEC;
}
if (shflags & SHF_WRITE)
prot |= SP_WRITE;
if (shflags & SHF_ALLOC)
flags |= SF_ALLOC;
if (!strncmp(name,".gnu.linkonce",13))
flags |= SF_LINKONCE;
return add_section(ou,name,data,size,type,flags,prot,align,FALSE);
}
void elf_add_symbol(struct GlobalVars *gv,struct ObjectUnit *ou,
char *symname,uint8_t flags,int shndx,uint32_t shtype,
uint8_t sttype,uint8_t stbind,lword value,uint32_t size)
{
struct LinkFile *lf = ou->lnkfile;
struct Section *sec;
uint8_t type = 0;
if (flags & SYMF_SHLIB) {
/* don't import linker symbols from shared objects - we make our own */
int i;
for (i=0; i<(sizeof(elf_symnames)/sizeof(elf_symnames[0])); i++) {
if (!strcmp(elf_symnames[i],symname))
return;
}
}
switch (shndx) {
case SHN_UNDEF:
sec = NULL; /* ignore xrefs for now */
break;
/* assign a section for ABS and COMMON symbols */
case SHN_ABS:
sec = abs_section(ou);
type = SYM_ABS;
break;
case SHN_COMMON:
sec = common_section(gv,ou);
type = SYM_COMMON;
break;
/* reloc symbols have a definite section to which they belong */
default:
if (shtype == SHT_DYNSYM) {
/* just put dynamic symbols into the first section -
the section index might be wrong in .dynsym */
sec = abs_section(ou);
}
else if (!(sec = find_sect_id(ou,shndx))) {
/* a section with this index doesn't exist! */
if (sttype != STT_SECTION)
error(53,lf->pathname,symname,lf->objname,shndx);
}
type = SYM_RELOC;
break;
}
if (sttype == STT_SECTION)
sec = NULL; /* ignore section defines - will be reproduced */
if (sec) {
if (sttype > STT_FILE) {
/* illegal symbol type */
error(54,lf->pathname,(int)sttype,symname,lf->objname);
sttype = STT_NOTYPE;
}
switch (stbind) {
case STB_LOCAL:
stbind = SYMB_LOCAL;
break;
case STB_GLOBAL:
stbind = SYMB_GLOBAL;
break;
case STB_WEAK:
stbind = SYMB_WEAK;
break;
default: /* illegal binding type */
error(55,lf->pathname,symname,stbind,lf->objname);
stbind = SYMB_LOCAL;
break;
}
/* add a new symbol definition */
if (stbind == SYMB_LOCAL)
addlocsymbol(gv,sec,symname,NULL,value,type,flags,sttype,size);
else
addsymbol(gv,sec,symname,NULL,value,type,flags,sttype,stbind,size,TRUE);
}
}
/*****************************************************************/
/* Link ELF */
/*****************************************************************/
int elf_targetlink(struct GlobalVars *gv,struct LinkedSection *ls,
struct Section *s)
/* returns 1, if target requires the combination of the two sections, */
/* returns -1, if target doesn't want to combine them, */
/* returns 0, if target doesn't care - standard linking rules are used. */
{
return 0;
}
struct Symbol *elf_makelnksym(struct GlobalVars *gv,int idx)
{
struct Symbol *sym = addlnksymbol(gv,elf_symnames[idx],0,SYM_ABS,
SYMF_LNKSYM,SYMI_OBJECT,SYMB_GLOBAL,0);
sym->extra = idx; /* for easy ident. in elf_setlnksym */
switch (idx) {
case SDABASE:
case SDA2BASE:
sym->type = SYM_RELOC;
sym->value = (lword)fff[gv->dest_format]->baseoff;
break;
case GLOBOFFSTAB:
sym->value = fff[gv->dest_format]->gotoff;
gv->got_base_name = elf_symnames[idx];
break;
case PROCLINKTAB:
gv->plt_base_name = elf_symnames[idx];
break;
}
return sym;
}
struct Symbol *elf_lnksym(struct GlobalVars *gv,struct Section *sec,
struct Reloc *xref)
/* Check for common ELF linker symbols. */
{
int i;
if (!gv->dest_object) {
for (i=0; i<(sizeof(elf_symnames)/sizeof(elf_symnames[0])); i++) {
if (!strcmp(elf_symnames[i],xref->xrefname))
return elf_makelnksym(gv,i); /* new linker symbol created */
}
}
return NULL;
}
void elf_setlnksym(struct GlobalVars *gv,struct Symbol *xdef)
/* Initialize common ELF linker symbol structure during resolve_xref() */
{
if (xdef->flags & SYMF_LNKSYM) {
struct LinkedSection *ls;
switch (xdef->extra) {
case SDABASE:
if (!(ls = find_lnksec(gv,sdata_name,ST_DATA,0,0,0)))
if (!(ls = find_lnksec(gv,sbss_name,ST_UDATA,0,0,0)))
ls = smalldata_section(gv);
xdef->relsect = (struct Section *)ls->sections.first;
break;
case SDA2BASE:
if (!(ls = find_lnksec(gv,sdata2_name,ST_DATA,0,0,0)))
if (!(ls = find_lnksec(gv,sbss2_name,ST_UDATA,0,0,0)))
ls = smalldata_section(gv);
xdef->relsect = (struct Section *)ls->sections.first;
break;
case CTORS:
if (ls = find_lnksec(gv,ctors_name,0,0,0,0)) {
xdef->type = SYM_RELOC;
xdef->relsect = (struct Section *)ls->sections.first;
}
break;
case DTORS:
if (ls = find_lnksec(gv,dtors_name,0,0,0,0)) {
xdef->type = SYM_RELOC;
xdef->relsect = (struct Section *)ls->sections.first;
}
break;
case GLOBOFFSTAB:
if (ls = find_lnksec(gv,got_name,0,0,0,0)) {
xdef->type = SYM_RELOC;
xdef->relsect = (struct Section *)ls->sections.first;
}
break;
case PROCLINKTAB:
if (ls = find_lnksec(gv,plt_name,0,0,0,0)) {
xdef->type = SYM_RELOC;
xdef->relsect = (struct Section *)ls->sections.first;
}
break;
case DYNAMICSYM:
if (ls = find_lnksec(gv,dyn_name,0,0,0,0)) {
xdef->value = ls->base;
}
/* @@@ when .dynamic was not created _DYNAMIC stays NULL - ok? */
break;
}
xdef->flags &= ~SYMF_LNKSYM; /* do not init again */
}
}
struct Section *elf_dyntable(struct GlobalVars *gv,
unsigned long initial_size,
unsigned long initial_offset,
uint8_t sectype,uint8_t secflags,
uint8_t secprot,int type)
/* return got/plt section, create new when missing */
{
static const char fn[] = "elf_dyntable():";
static const char *secname[] = { NULL, got_name, plt_name };
struct Section *sec,**secp;
struct ObjectUnit *ou;
int symidx = -1;
switch (type) {
case GOT_ENTRY:
secp = &gotsec;
symidx = GLOBOFFSTAB;
break;
case PLT_ENTRY:
secp = &pltsec;
symidx = PROCLINKTAB;
break;
default:
ierror("%s wrong type: %d",fn,type);
break;
}
if (sec = *secp)
return sec;
if (gv->dynobj == NULL)
ierror("%s no dynobj",fn);
/* Section does not exist - create it.
The offset field is used for the next table entry offset. */
sec = add_section(gv->dynobj,(char *)secname[type],NULL,initial_size,
sectype,secflags,secprot,2,TRUE);
sec->offset = initial_offset;
*secp = sec;
/* create _GLOBAL_OFFSET_TABLE_ or _PROCEDURE_LINKAGE_TABLE_ linker symbol */
if (symidx >= 0) {
if (!findlnksymbol(gv,elf_symnames[symidx]))
elf_makelnksym(gv,symidx);
}
return sec;
}
void elf_adddynsym(struct Symbol *sym)
{
if (sym->flags & SYMF_DYNIMPORT) {
elf_addsym(&elfdsymlist,sym->name,0,0,STB_GLOBAL,STT_NOTYPE,SHN_UNDEF);
}
else if (sym->flags & SYMF_DYNEXPORT) {
struct DynSymNode *dsn = alloc(sizeof(struct DynSymNode));
/* section index and value need to be fixed later for these entries! */
dsn->idx = elf_addsym(&elfdsymlist,sym->name,0,sym->size,
elf_getbind(sym),elf_getinfo(sym),0);
dsn->sym = sym;
addtail(&elfdynsymlist,&dsn->n);
}
else
ierror("elf_adddynsym(): <%s> was not flagged as dynamic",sym->name);
}
void elf_dynreloc(struct ObjectUnit *ou,struct Reloc *r,int relafmt,
size_t elfrelsize)
{
const char *secname;
struct Section **secp;
uint8_t dynflag = SYMF_DYNIMPORT;
switch (r->rtype) {
case R_COPY:
dynflag = SYMF_DYNEXPORT;
/* fall through */
case R_GLOBDAT:
case R_LOADREL:
secp = &elfdynrelocs;
secname = dynrel_name[relafmt?1:0];
r->flags |= RELF_DYN;
break;
case R_JMPSLOT:
secp = &elfpltrelocs;
secname = pltrel_name[relafmt?1:0];
r->flags |= RELF_PLT;
break;
case R_ABS:
return;
default:
ierror("elf_dynreloc(): wrong rtype %s (%d)",
reloc_name[r->rtype],(int)r->rtype);
break;
}
/* make sure that dynamic relocation section exists */
if (*secp == NULL)
*secp = add_section(ou,secname,NULL,0,ST_DATA,SF_ALLOC,SP_READ,2,TRUE);
/* increase size for new entry */
(*secp)->size += elfrelsize;
/* allocate referenced symbol in .dynsym and .dynstr */
if (r->xrefname) {
struct Symbol *sym = r->relocsect.symbol;
if (!(sym->flags & SYMF_DYNLINK)) {
/* add symbol to .dynsym symbol list, if not already present */
sym->flags |= dynflag;
elf_adddynsym(sym);
}
}
}
struct Section *elf_initdynlink(struct GlobalVars *gv)
{
struct ObjectUnit *ou = gv->dynobj;
struct Symbol *sym;
struct Section *dynsec;
/* set endianess for output file */
elf_endianess = fff[gv->dest_format]->endianess;
/* init dynamic symbol list */
initlist(&elfdynsymlist);
/* allocate .interp section for dynamically linked executables only */
if (!gv->dest_sharedobj)
add_section(ou,".interp",(uint8_t *)gv->interp_path,
strlen(gv->interp_path)+1,ST_DATA,SF_ALLOC,SP_READ,0,TRUE);
/* .hash, .dynsym, .dynstr and .dynamic are always present.
Set them to an initial size. They will grow with dynamic symbols added. */
add_section(ou,hash_name,NULL,0,ST_DATA,SF_ALLOC,SP_READ,2,TRUE);
add_section(ou,dynsym_name,NULL,0,ST_DATA,SF_ALLOC,SP_READ,2,TRUE);
add_section(ou,dynstr_name,NULL,0,ST_DATA,SF_ALLOC,SP_READ,0,TRUE);
dynsec = add_section(ou,dyn_name,NULL,0,ST_DATA,SF_ALLOC,
SP_READ|SP_WRITE,2,TRUE);
/* assign symbol _DYNAMIC the address of the .dynamic section */
sym = elf_makelnksym(gv,DYNAMICSYM);
sym->flags |= SYMF_DYNEXPORT;
elf_adddynsym(sym);
return dynsec;
}
struct Symbol *elf_pltgotentry(struct GlobalVars *gv,struct Section *sec,
DynArg a,uint8_t entrysymtype,
unsigned long offsadd,unsigned long sizeadd,
int etype,bool relaflag,
size_t relocsize,size_t addrsize)
/* Make a table entry for indirectly accessing a location from an external
symbol defintion (GOT_ENTRY/PLT_ENTRY) or a local relocation (GOT_LOCAL).
The entry has a size of offsadd bytes, while the table section sec will
become sizeadd bytes larger per entry. */
{
const char *fn = "elf_pltgotentry():";
char entryname[MAXLEN];
struct Symbol *tabsym;
struct Section *refsec;
unsigned long refoffs;
/* determine reference section and offset of ext. symbol or local reloc */
if (etype == GOT_LOCAL) {
refsec = a.rel->relocsect.ptr;
refoffs = a.rel->offset;
}
else {
refsec = a.sym->relsect;
refoffs = (unsigned long)a.sym->value;
}
/* generate internal symbol name for this reference */
snprintf(entryname,MAXLEN," %s@%lx@%lx",
sec->name,(unsigned long)refsec,refoffs);
/* create internal symbol, or return old one, when already present */
tabsym = addsymbol(gv,sec,allocstring(entryname),NULL,(lword)sec->offset,
SYM_RELOC,0,entrysymtype,SYMB_LOCAL,offsadd,FALSE);
/* tabsym is NULL when it was just created, otherwise we already got it */
if (tabsym == NULL) {
static uint8_t dyn_reloc_types[] = { R_NONE,R_GLOBDAT,R_JMPSLOT,R_COPY };
struct Reloc *r;
uint8_t rtype;
tabsym = findlocsymbol(gv,sec->obj,entryname);
if (tabsym == NULL) {
ierror("%s %s-symbol refering to %s+%lx disappeared",
fn,sec->name,refsec->name,refoffs);
}
/* create a relocation for the new entry */
if (etype == GOT_LOCAL) {
/* local symbol: GOT relocation can be resolved now */
r = newreloc(gv,sec,NULL,refsec,0,sec->offset,R_ABS,(lword)refoffs);
}
else {
/* we need a dynamic linker relocation at the entry's offset */
r = newreloc(gv,sec,a.sym->name,NULL,0,sec->offset,
dyn_reloc_types[etype],0);
r->relocsect.symbol = a.sym; /* resolve with external symbol */
/* Possible enhancement: Find out whether referenced symbol resides
in an uninitialized section, without a relocation, then we don't
need an R_COPY relocation either! */
}
addreloc(sec,r,0,addrsize,-1); /* size,mask only important for R_ABS */
elf_dynreloc(gv->dynobj,r,relaflag,relocsize);
/* increase offset and size counters of table-section */
sec->offset += offsadd;
sec->size += sizeadd;
}
return tabsym;
}
struct Symbol *elf_bssentry(struct GlobalVars *gv,const char *secname,
struct Symbol *xdef,bool relaflag,
size_t relocsize,size_t addrsize)
/* Allocate space for a copy-object in a .bss or .sbss section and create
a R_COPY relocation to the original symbol in the shared object. */
{
struct Symbol *newxdef;
if (gv->dynobj == NULL)
ierror("elf_bssentry(): no dynobj");
newxdef = bss_entry(gv->dynobj,secname,xdef);
if (newxdef) {
/* entry in BSS was done, so we need a R_COPY relocation */
struct Reloc *r;
xdef = newxdef;
r = newreloc(gv,xdef->relsect,xdef->name,NULL,0,0,R_COPY,0);
r->relocsect.symbol = xdef;
addreloc(xdef->relsect,r,0,addrsize,-1); /* mask/size irrel. for R_COPY */
elf_dynreloc(xdef->relsect->obj,r,relaflag,relocsize);
}
return xdef;
}
size_t elf_num_buckets(size_t symcount)
/* determine optimal number of buckets in dynamic symbol hash table */
{
int i;
size_t best_num;
for (i=0; elf_buckets[i]; i++) {
best_num = elf_buckets[i];
if (symcount < elf_buckets[i+1])
break;
}
return best_num;
}
void elf_putsymtab(uint8_t *p,struct SymTabList *sl)
/* write all SymTabList nodes sequentially into memory */
{
size_t sz = sl->elfsymsize;
struct SymbolNode *sym;
while (sym = (struct SymbolNode *)remhead(&sl->l)) {
memcpy(p,sym->elfsym,sz);
p += sz;
}
}
/*****************************************************************/
/* Write ELF */
/*****************************************************************/
unsigned long elf_numsegments(struct GlobalVars *gv)
{
int segcnt = 0;
struct Phdr *p = gv->phdrlist;
while (p) {
if (p->flags & PHDR_USED)
segcnt++;
p = p->next;
}
return segcnt;
}
uint8_t elf_getinfo(struct Symbol *sym)
{
uint8_t type = STT_NOTYPE;
switch (sym->info) {
case SYMI_NOTYPE:
break; /* @@@ Is this allowed? */
case SYMI_OBJECT:
type = STT_OBJECT;
break;
case SYMI_FUNC:
type = STT_FUNC;
break;
case SYMI_SECTION:
ierror("elf_getinfo(): STT_SECTION symbol detected");
type = STT_SECTION;
break;
case SYMI_FILE:
type = STT_FILE;
break;
default:
ierror("elf_getinfo(): Illegal symbol info: %d",(int)sym->info);
break;
}
return type;
}
uint8_t elf_getbind(struct Symbol *sym)
{
uint8_t bind = STB_GLOBAL;
switch (sym->bind) {
case SYMB_LOCAL:
bind = STB_LOCAL;
break;
case SYMB_GLOBAL:
bind = STB_GLOBAL;
break;
case SYMB_WEAK:
bind = STB_WEAK;
break;
default:
ierror("elf_getbind(): Illegal symbol binding: %d",(int)sym->bind);
break;
}
return bind;
}
uint16_t elf_getshndx(struct GlobalVars *gv,
struct Symbol *sym,uint8_t symtype)
{
uint16_t shndx = SHN_UNDEF;
switch (sym->type) {
case SYM_INDIR:
/* can't reproduce unsupported symbol type */
error(33,fff[gv->dest_format]->tname,sym->name,sym_bind[sym->bind],
sym_type[sym->type],sym_info[sym->info]);
case SYM_UNDEF:
shndx = SHN_UNDEF;
break;
case SYM_ABS:
shndx = SHN_ABS;
break;
case SYM_RELOC:
if (symtype > STT_FUNC)
ierror("elf_getshndx(): %s is relocatable, but not a "
"function or object (type %d)",sym->name,(int)symtype);
shndx = (uint16_t)sym->relsect->lnksec->index;
break;
case SYM_COMMON:
shndx = SHN_COMMON;
break;
default:
ierror("elf_getshndx(): Illegal symbol type: %d",(int)sym->type);
break;
}
return shndx;
}
void elf_putstrtab(uint8_t *p,struct StrTabList *sl)
/* write all StrTabList nodes sequentially into memory */
{
struct StrTabNode *stn;
while (stn = (struct StrTabNode *)remhead(&sl->l)) {
const char *s;
char c;
s = stn->str;
do {
c = *s++;
*p++ = c;
} while (c);
}
}
uint32_t elf_addstrlist(struct StrTabList *sl,const char *s)
/* add a new string to an ELF string table and return its index */
{
struct StrTabNode **chain,*sn;
if (sl->hashtab == NULL) {
/* initialize an unused string list */
initlist(&sl->l);
sl->hashtab = alloczero(sl->htabsize * sizeof(struct StrTabNode *));
elf_addstrlist(sl,noname);
}
chain = &sl->hashtab[elf_hash(s) % sl->htabsize];
/* search string in hash table */
while (sn = *chain) {
if (!strcmp(s,sn->str))
return sn->index; /* it's already in, return index */
chain = &sn->hashchain;
}
/* new string table entry */
*chain = sn = alloc(sizeof(struct StrTabNode));
sn->hashchain = NULL;
sn->str = s;
sn->index = sl->nextindex;
addtail(&sl->l,&sn->n);
sl->nextindex += (uint32_t)strlen(s) + 1;
return sn->index;
}
uint32_t elf_addshdrstr(const char *s)
{
return elf_addstrlist(&elfshstrlist,s);
}
uint32_t elf_addstr(const char *s)
{
return elf_addstrlist(&elfstringlist,s);
}
uint32_t elf_adddynstr(const char *s)
{
return elf_addstrlist(&elfdstrlist,s);
}
uint32_t elf_addsym(struct SymTabList *sl,const char *name,uint64_t value,
uint64_t size,uint8_t bind,uint8_t type,uint16_t shndx)
{
struct SymbolNode **chain,*sn;
void *sym;
if (name == NULL) /* do nothing, return first index */
return 0;
chain = &sl->hashtab[elf_hash(name) % sl->htabsize];
while (sn = *chain)
chain = &sn->hashchain;
/* new symbol table entry */
*chain = sn = alloc(sizeof(struct SymbolNode));
sn->hashchain = NULL;
sn->name = name;
sn->index = sl->nextindex++;
sn->shndx = shndx;
sn->elfsym = sym = alloc(sl->elfsymsize);
addtail(&sl->l,&sn->n);
/* initialize ELF symbol */
sl->initsym(sym,elf_addstrlist(sl->strlist,name),value,size,
bind,type,shndx,elf_endianess==_BIG_ENDIAN_);
return sn->index;
}
void elf_initsymlist(struct SymTabList *sl,struct StrTabList *strl,
size_t tabsize,size_t symsize,
void (*init)(void *,uint32_t,uint64_t,uint64_t,
uint8_t,uint8_t,uint16_t,bool))
{
initlist(&sl->l);
sl->htabsize = tabsize;
sl->hashtab = alloczero(tabsize * sizeof(struct SymbolNode *));
sl->strlist = strl;
sl->elfsymsize = symsize;
sl->initsym = init;
sl->nextindex = sl->globalindex = 0;
elf_addsym(sl,noname,0,0,0,0,SHN_UNDEF);
}
struct SymbolNode *elf_findSymNode(struct SymTabList *sl,const char *name)
/* Find an ELF symbol node by its name.
Return pointer to it, or NULL when not found. */
{
struct SymbolNode **chain = &sl->hashtab[elf_hash(name) % sl->htabsize];
struct SymbolNode *sym;
while (sym = *chain) {
if (!strcmp(name,sym->name))
return sym;
chain = &sym->hashchain;
}
return NULL;
}
static uint32_t elf_findsymidx(struct SymTabList *sl,const char *name,
uint16_t shndx)
/* find an ELF symbol by its name and shndx */
/* return its symbol table index, index=0 means 'not found' */
{
struct SymbolNode **chain = &sl->hashtab[elf_hash(name) % sl->htabsize];
struct SymbolNode *sym;
while (sym = *chain) {
if (!strcmp(name,sym->name) && sym->shndx==shndx)
return sym->index;
chain = &sym->hashchain;
}
return 0;
}
uint32_t elf_extsymidx(struct SymTabList *sl,const char *name)
/* return index of external symbol with name from SymTabList */
{
uint32_t symidx;
if (!(symidx = elf_findsymidx(sl,name,SHN_COMMON)))
if (!(symidx = elf_findsymidx(sl,name,SHN_UNDEF)))
symidx = elf_addsym(sl,name,0,0,STB_GLOBAL,STT_NOTYPE,SHN_UNDEF);
return symidx;
}
void elf_ident(void *p,bool be,uint8_t class,uint16_t type,uint16_t mach)
{
struct Elf_CommonHdr *hdr = (struct Elf_CommonHdr *)p;
strncpy((char *)hdr->e_ident,ELFid,4);
hdr->e_ident[EI_CLASS] = class;
hdr->e_ident[EI_DATA] = be ? ELFDATA2MSB : ELFDATA2LSB;
hdr->e_ident[EI_VERSION] = ELF_VER;
memset(&hdr->e_ident[EI_PAD],0,EI_NIDENT-EI_PAD);
write16(be,hdr->e_type,type);
write16(be,hdr->e_machine,mach);
write32(be,hdr->e_version,ELF_VER);
}
void elf_addsymlist(struct GlobalVars *gv,struct SymTabList *sl,
uint8_t bind,uint8_t type)
/* add all symbols with specified bind and type to the ELF symbol list */
{
struct LinkedSection *ls = (struct LinkedSection *)gv->lnksec.first;
struct LinkedSection *nextls;
struct Symbol *nextsym,*sym;
while (nextls = (struct LinkedSection *)ls->n.next) {
sym = (struct Symbol *)ls->symbols.first;
while (nextsym = (struct Symbol *)sym->n.next) {
uint8_t symtype = elf_getinfo(sym);
uint8_t symbind = elf_getbind(sym);
if (symbind == bind && (!type || (symtype == type))) {
if (!discard_symbol(gv,sym)) {
remnode(&sym->n);
elf_addsym(sl,sym->name,sym->value,sym->size,symbind,symtype,
elf_getshndx(gv,sym,symtype));
}
}
sym = nextsym;
}