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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// PE (Portable Executable) file writing
// http://www.microsoft.com/whdc/system/platform/firmware/PECOFF.mspx
#include "l.h"
#include "../ld/lib.h"
#include "../ld/pe.h"
#include "../ld/dwarf.h"
// DOS stub that prints out
// "This program cannot be run in DOS mode."
static char dosstub[] =
{
0x4d, 0x5a, 0x90, 0x00, 0x03, 0x00, 0x04, 0x00,
0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00,
0x8b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00,
0x0e, 0x1f, 0xba, 0x0e, 0x00, 0xb4, 0x09, 0xcd,
0x21, 0xb8, 0x01, 0x4c, 0xcd, 0x21, 0x54, 0x68,
0x69, 0x73, 0x20, 0x70, 0x72, 0x6f, 0x67, 0x72,
0x61, 0x6d, 0x20, 0x63, 0x61, 0x6e, 0x6e, 0x6f,
0x74, 0x20, 0x62, 0x65, 0x20, 0x72, 0x75, 0x6e,
0x20, 0x69, 0x6e, 0x20, 0x44, 0x4f, 0x53, 0x20,
0x6d, 0x6f, 0x64, 0x65, 0x2e, 0x0d, 0x0d, 0x0a,
0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
// Note: currently only up to 8 chars plus \0.
static char *symlabels[] = {
"symtab", "esymtab", "pclntab", "epclntab"
};
static Sym *rsrcsym;
static char symnames[256];
static int nextsymoff;
int32 PESECTHEADR;
int32 PEFILEHEADR;
static int pe64;
static int nsect;
static int nextsectoff;
static int nextfileoff;
static int textsect;
static IMAGE_FILE_HEADER fh;
static IMAGE_OPTIONAL_HEADER oh;
static PE64_IMAGE_OPTIONAL_HEADER oh64;
static IMAGE_SECTION_HEADER sh[16];
static IMAGE_DATA_DIRECTORY* dd;
#define set(n, v) (pe64 ? (oh64.n = v) : (oh.n = v))
#define put(v) (pe64 ? vputl(v) : lputl(v))
typedef struct Imp Imp;
struct Imp {
Sym* s;
uvlong off;
Imp* next;
};
typedef struct Dll Dll;
struct Dll {
char* name;
uvlong nameoff;
uvlong thunkoff;
Imp* ms;
Dll* next;
};
static Dll* dr;
static Sym *dexport[1024];
static int nexport;
static IMAGE_SECTION_HEADER*
addpesection(char *name, int sectsize, int filesize)
{
IMAGE_SECTION_HEADER *h;
if(nsect == 16) {
diag("too many sections");
errorexit();
}
h = &sh[nsect++];
strncpy((char*)h->Name, name, sizeof(h->Name));
h->VirtualSize = sectsize;
h->VirtualAddress = nextsectoff;
nextsectoff = rnd(nextsectoff+sectsize, PESECTALIGN);
h->PointerToRawData = nextfileoff;
if(filesize > 0) {
h->SizeOfRawData = rnd(filesize, PEFILEALIGN);
nextfileoff += h->SizeOfRawData;
}
return h;
}
static void
chksectoff(IMAGE_SECTION_HEADER *h, vlong off)
{
if(off != h->PointerToRawData) {
diag("%s.PointerToRawData = %#llux, want %#llux", (char *)h->Name, (vlong)h->PointerToRawData, off);
errorexit();
}
}
static void
chksectseg(IMAGE_SECTION_HEADER *h, Segment *s)
{
if(s->vaddr-PEBASE != h->VirtualAddress) {
diag("%s.VirtualAddress = %#llux, want %#llux", (char *)h->Name, (vlong)h->VirtualAddress, (vlong)(s->vaddr-PEBASE));
errorexit();
}
if(s->fileoff != h->PointerToRawData) {
diag("%s.PointerToRawData = %#llux, want %#llux", (char *)h->Name, (vlong)h->PointerToRawData, (vlong)(s->fileoff));
errorexit();
}
}
void
peinit(void)
{
int32 l;
switch(thechar) {
// 64-bit architectures
case '6':
pe64 = 1;
l = sizeof(oh64);
dd = oh64.DataDirectory;
break;
// 32-bit architectures
default:
l = sizeof(oh);
dd = oh.DataDirectory;
break;
}
PEFILEHEADR = rnd(sizeof(dosstub)+sizeof(fh)+l+sizeof(sh), PEFILEALIGN);
PESECTHEADR = rnd(PEFILEHEADR, PESECTALIGN);
nextsectoff = PESECTHEADR;
nextfileoff = PEFILEHEADR;
}
static void
pewrite(void)
{
cseek(0);
cwrite(dosstub, sizeof dosstub);
strnput("PE", 4);
// TODO: This code should not assume that the
// memory representation is little-endian or
// that the structs are packed identically to
// their file representation.
cwrite(&fh, sizeof fh);
if(pe64)
cwrite(&oh64, sizeof oh64);
else
cwrite(&oh, sizeof oh);
cwrite(sh, nsect * sizeof sh[0]);
}
static void
strput(char *s)
{
int n;
for(n=0; *s; n++)
cput(*s++);
cput('\0');
n++;
// string must be padded to even size
if(n%2)
cput('\0');
}
static Dll*
initdynimport(void)
{
Imp *m;
Dll *d;
Sym *s, *dynamic;
dr = nil;
m = nil;
for(s = allsym; s != S; s = s->allsym) {
if(!s->reachable || !s->dynimpname || s->dynexport)
continue;
for(d = dr; d != nil; d = d->next) {
if(strcmp(d->name,s->dynimplib) == 0) {
m = mal(sizeof *m);
break;
}
}
if(d == nil) {
d = mal(sizeof *d);
d->name = s->dynimplib;
d->next = dr;
dr = d;
m = mal(sizeof *m);
}
m->s = s;
m->next = d->ms;
d->ms = m;
}
dynamic = lookup(".windynamic", 0);
dynamic->reachable = 1;
dynamic->type = SWINDOWS;
for(d = dr; d != nil; d = d->next) {
for(m = d->ms; m != nil; m = m->next) {
m->s->type = SWINDOWS | SSUB;
m->s->sub = dynamic->sub;
dynamic->sub = m->s;
m->s->value = dynamic->size;
dynamic->size += PtrSize;
}
dynamic->size += PtrSize;
}
return dr;
}
static void
addimports(IMAGE_SECTION_HEADER *datsect)
{
IMAGE_SECTION_HEADER *isect;
uvlong n, oftbase, ftbase;
vlong startoff, endoff;
Imp *m;
Dll *d;
Sym* dynamic;
startoff = cpos();
dynamic = lookup(".windynamic", 0);
// skip import descriptor table (will write it later)
n = 0;
for(d = dr; d != nil; d = d->next)
n++;
cseek(startoff + sizeof(IMAGE_IMPORT_DESCRIPTOR) * (n + 1));
// write dll names
for(d = dr; d != nil; d = d->next) {
d->nameoff = cpos() - startoff;
strput(d->name);
}
// write function names
for(d = dr; d != nil; d = d->next) {
for(m = d->ms; m != nil; m = m->next) {
m->off = nextsectoff + cpos() - startoff;
wputl(0); // hint
strput(m->s->dynimpname);
}
}
// write OriginalFirstThunks
oftbase = cpos() - startoff;
n = cpos();
for(d = dr; d != nil; d = d->next) {
d->thunkoff = cpos() - n;
for(m = d->ms; m != nil; m = m->next)
put(m->off);
put(0);
}
// add pe section and pad it at the end
n = cpos() - startoff;
isect = addpesection(".idata", n, n);
isect->Characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA|
IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE;
chksectoff(isect, startoff);
strnput("", isect->SizeOfRawData - n);
endoff = cpos();
// write FirstThunks (allocated in .data section)
ftbase = dynamic->value - datsect->VirtualAddress - PEBASE;
cseek(datsect->PointerToRawData + ftbase);
for(d = dr; d != nil; d = d->next) {
for(m = d->ms; m != nil; m = m->next)
put(m->off);
put(0);
}
// finally write import descriptor table
cseek(startoff);
for(d = dr; d != nil; d = d->next) {
lputl(isect->VirtualAddress + oftbase + d->thunkoff);
lputl(0);
lputl(0);
lputl(isect->VirtualAddress + d->nameoff);
lputl(datsect->VirtualAddress + ftbase + d->thunkoff);
}
lputl(0); //end
lputl(0);
lputl(0);
lputl(0);
lputl(0);
// update data directory
dd[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress = isect->VirtualAddress;
dd[IMAGE_DIRECTORY_ENTRY_IMPORT].Size = isect->VirtualSize;
dd[IMAGE_DIRECTORY_ENTRY_IAT].VirtualAddress = dynamic->value - PEBASE;
dd[IMAGE_DIRECTORY_ENTRY_IAT].Size = dynamic->size;
cseek(endoff);
}
static int
scmp(const void *p1, const void *p2)
{
Sym *s1, *s2;
s1 = *(Sym**)p1;
s2 = *(Sym**)p2;
return strcmp(s1->dynimpname, s2->dynimpname);
}
static void
initdynexport(void)
{
Sym *s;
nexport = 0;
for(s = allsym; s != S; s = s->allsym) {
if(!s->reachable || !s->dynimpname || !s->dynexport)
continue;
if(nexport+1 > sizeof(dexport)/sizeof(dexport[0])) {
diag("pe dynexport table is full");
errorexit();
}
dexport[nexport] = s;
nexport++;
}
qsort(dexport, nexport, sizeof dexport[0], scmp);
}
void
addexports(void)
{
IMAGE_SECTION_HEADER *sect;
IMAGE_EXPORT_DIRECTORY e;
int size, i, va, va_name, va_addr, va_na, v;
size = sizeof e + 10*nexport + strlen(outfile) + 1;
for(i=0; i<nexport; i++)
size += strlen(dexport[i]->dynimpname) + 1;
if (nexport == 0)
return;
sect = addpesection(".edata", size, size);
sect->Characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_READ;
chksectoff(sect, cpos());
va = sect->VirtualAddress;
dd[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress = va;
dd[IMAGE_DIRECTORY_ENTRY_EXPORT].Size = sect->VirtualSize;
va_name = va + sizeof e + nexport*4;
va_addr = va + sizeof e;
va_na = va + sizeof e + nexport*8;
e.Characteristics = 0;
e.MajorVersion = 0;
e.MinorVersion = 0;
e.NumberOfFunctions = nexport;
e.NumberOfNames = nexport;
e.Name = va + sizeof e + nexport*10; // Program names.
e.Base = 1;
e.AddressOfFunctions = va_addr;
e.AddressOfNames = va_name;
e.AddressOfNameOrdinals = va_na;
// put IMAGE_EXPORT_DIRECTORY
for (i=0; i<sizeof(e); i++)
cput(((char*)&e)[i]);
// put EXPORT Address Table
for(i=0; i<nexport; i++)
lputl(dexport[i]->value - PEBASE);
// put EXPORT Name Pointer Table
v = e.Name + strlen(outfile)+1;
for(i=0; i<nexport; i++) {
lputl(v);
v += strlen(dexport[i]->dynimpname)+1;
}
// put EXPORT Ordinal Table
for(i=0; i<nexport; i++)
wputl(i);
// put Names
strnput(outfile, strlen(outfile)+1);
for(i=0; i<nexport; i++)
strnput(dexport[i]->dynimpname, strlen(dexport[i]->dynimpname)+1);
strnput("", sect->SizeOfRawData - size);
}
void
dope(void)
{
Sym *rel;
/* relocation table */
rel = lookup(".rel", 0);
rel->reachable = 1;
rel->type = SELFROSECT;
initdynimport();
initdynexport();
}
/*
* For more than 8 characters section names, name contains a slash (/) that is
* followed by an ASCII representation of a decimal number that is an offset into
* the string table.
* reference: pecoff_v8.docx Page 24.
* <http://www.microsoft.com/whdc/system/platform/firmware/PECOFFdwn.mspx>
*/
IMAGE_SECTION_HEADER*
newPEDWARFSection(char *name, vlong size)
{
IMAGE_SECTION_HEADER *h;
char s[8];
if(size == 0)
return nil;
if(nextsymoff+strlen(name)+1 > sizeof(symnames)) {
diag("pe string table is full");
errorexit();
}
strcpy(&symnames[nextsymoff], name);
sprint(s, "/%d\0", nextsymoff+4);
nextsymoff += strlen(name);
symnames[nextsymoff] = 0;
nextsymoff ++;
h = addpesection(s, size, size);
h->Characteristics = IMAGE_SCN_MEM_READ|
IMAGE_SCN_MEM_DISCARDABLE;
return h;
}
static void
addsymtable(void)
{
IMAGE_SECTION_HEADER *h;
int i, size;
Sym *s;
fh.NumberOfSymbols = sizeof(symlabels)/sizeof(symlabels[0]);
size = nextsymoff + 4 + 18*fh.NumberOfSymbols;
h = addpesection(".symtab", size, size);
h->Characteristics = IMAGE_SCN_MEM_READ|
IMAGE_SCN_MEM_DISCARDABLE;
chksectoff(h, cpos());
fh.PointerToSymbolTable = cpos();
// put COFF symbol table
for (i=0; i<fh.NumberOfSymbols; i++) {
s = rlookup(symlabels[i], 0);
strnput(s->name, 8);
lputl(datoff(s->value));
wputl(textsect);
wputl(0x0308); // "array of structs"
cput(2); // storage class: external
cput(0); // no aux entries
}
// put COFF string table
lputl(nextsymoff + 4);
for (i=0; i<nextsymoff; i++)
cput(symnames[i]);
strnput("", h->SizeOfRawData - size);
}
void
setpersrc(Sym *sym)
{
if(rsrcsym != nil)
diag("too many .rsrc sections");
rsrcsym = sym;
}
void
addpersrc(void)
{
IMAGE_SECTION_HEADER *h;
uchar *p;
uint32 val;
Reloc *r;
if(rsrcsym == nil)
return;
h = addpesection(".rsrc", rsrcsym->size, rsrcsym->size);
h->Characteristics = IMAGE_SCN_MEM_READ|
IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_INITIALIZED_DATA;
chksectoff(h, cpos());
// relocation
for(r=rsrcsym->r; r<rsrcsym->r+rsrcsym->nr; r++) {
p = rsrcsym->p + r->off;
val = h->VirtualAddress + r->add;
// 32-bit little-endian
p[0] = val;
p[1] = val>>8;
p[2] = val>>16;
p[3] = val>>24;
}
cwrite(rsrcsym->p, rsrcsym->size);
strnput("", h->SizeOfRawData - rsrcsym->size);
// update data directory
dd[IMAGE_DIRECTORY_ENTRY_RESOURCE].VirtualAddress = h->VirtualAddress;
dd[IMAGE_DIRECTORY_ENTRY_RESOURCE].Size = h->VirtualSize;
}
static void
addexcept(IMAGE_SECTION_HEADER *text)
{
IMAGE_SECTION_HEADER *pdata, *xdata;
vlong startoff;
uvlong n;
Sym *sym;
if(thechar != '6')
return;
// write unwind info
sym = lookup("runtime.sigtramp", 0);
startoff = cpos();
lputl(9); // version=1, flags=UNW_FLAG_EHANDLER, rest 0
lputl(sym->value - PEBASE);
lputl(0);
n = cpos() - startoff;
xdata = addpesection(".xdata", n, n);
xdata->Characteristics = IMAGE_SCN_MEM_READ|
IMAGE_SCN_CNT_INITIALIZED_DATA;
chksectoff(xdata, startoff);
strnput("", xdata->SizeOfRawData - n);
// write a function table entry for the whole text segment
startoff = cpos();
lputl(text->VirtualAddress);
lputl(text->VirtualAddress + text->VirtualSize);
lputl(xdata->VirtualAddress);
n = cpos() - startoff;
pdata = addpesection(".pdata", n, n);
pdata->Characteristics = IMAGE_SCN_MEM_READ|
IMAGE_SCN_CNT_INITIALIZED_DATA;
chksectoff(pdata, startoff);
strnput("", pdata->SizeOfRawData - n);
dd[IMAGE_DIRECTORY_ENTRY_EXCEPTION].VirtualAddress = pdata->VirtualAddress;
dd[IMAGE_DIRECTORY_ENTRY_EXCEPTION].Size = pdata->VirtualSize;
}
void
asmbpe(void)
{
IMAGE_SECTION_HEADER *t, *d;
switch(thechar) {
default:
diag("unknown PE architecture");
errorexit();
case '6':
fh.Machine = IMAGE_FILE_MACHINE_AMD64;
break;
case '8':
fh.Machine = IMAGE_FILE_MACHINE_I386;
break;
}
t = addpesection(".text", segtext.len, segtext.len);
t->Characteristics = IMAGE_SCN_CNT_CODE|
IMAGE_SCN_CNT_INITIALIZED_DATA|
IMAGE_SCN_MEM_EXECUTE|IMAGE_SCN_MEM_READ;
chksectseg(t, &segtext);
textsect = nsect;
d = addpesection(".data", segdata.len, segdata.filelen);
d->Characteristics = IMAGE_SCN_CNT_INITIALIZED_DATA|
IMAGE_SCN_MEM_READ|IMAGE_SCN_MEM_WRITE;
chksectseg(d, &segdata);
if(!debug['s'])
dwarfaddpeheaders();
cseek(nextfileoff);
addimports(d);
addexports();
addsymtable();
addpersrc();
addexcept(t);
fh.NumberOfSections = nsect;
fh.TimeDateStamp = time(0);
fh.Characteristics = IMAGE_FILE_RELOCS_STRIPPED|
IMAGE_FILE_EXECUTABLE_IMAGE|IMAGE_FILE_DEBUG_STRIPPED;
if (pe64) {
fh.SizeOfOptionalHeader = sizeof(oh64);
fh.Characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE;
set(Magic, 0x20b); // PE32+
} else {
fh.SizeOfOptionalHeader = sizeof(oh);
fh.Characteristics |= IMAGE_FILE_32BIT_MACHINE;
set(Magic, 0x10b); // PE32
oh.BaseOfData = d->VirtualAddress;
}
set(MajorLinkerVersion, 3);
set(MinorLinkerVersion, 0);
set(SizeOfCode, t->SizeOfRawData);
set(SizeOfInitializedData, d->SizeOfRawData);
set(SizeOfUninitializedData, 0);
set(AddressOfEntryPoint, entryvalue()-PEBASE);
set(BaseOfCode, t->VirtualAddress);
set(ImageBase, PEBASE);
set(SectionAlignment, PESECTALIGN);
set(FileAlignment, PEFILEALIGN);
set(MajorOperatingSystemVersion, 4);
set(MinorOperatingSystemVersion, 0);
set(MajorImageVersion, 1);
set(MinorImageVersion, 0);
set(MajorSubsystemVersion, 4);
set(MinorSubsystemVersion, 0);
set(SizeOfImage, nextsectoff);
set(SizeOfHeaders, PEFILEHEADR);
if(strcmp(headstring, "windowsgui") == 0)
set(Subsystem, IMAGE_SUBSYSTEM_WINDOWS_GUI);
else
set(Subsystem, IMAGE_SUBSYSTEM_WINDOWS_CUI);
// Disable stack growth as we don't want Windows to
// fiddle with the thread stack limits, which we set
// ourselves to circumvent the stack checks in the
// Windows exception dispatcher.
// Commit size must be strictly less than reserve
// size otherwise reserve will be rounded up to a
// larger size, as verified with VMMap.
set(SizeOfStackReserve, 0x00010000);
set(SizeOfStackCommit, 0x0000ffff);
set(SizeOfHeapReserve, 0x00100000);
set(SizeOfHeapCommit, 0x00001000);
set(NumberOfRvaAndSizes, 16);
pewrite();
}