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/****************************************************************/
/* mdso: midipix dso scavenger */
/* Copyright (C) 2015--2021 SysDeer Technologies, LLC */
/* Released under GPLv2 and GPLv3; see COPYING.MDSO. */
/****************************************************************/
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <mdso/mdso.h>
#include <mdso/mdso_specs.h>
#include "mdso_object_impl.h"
#include "mdso_errinfo_impl.h"
#include "perk_consts.h"
#include "perk_structs.h"
struct mdso_symfn_refs {
unsigned char refs[16];
};
struct mdso_symentry_object {
struct pe_raw_coff_object_hdr hdr;
struct pe_raw_sec_hdr sec[2];
struct mdso_symfn_refs ref[1];
struct pe_raw_coff_reloc rel[2];
struct pe_raw_coff_symbol sym[9];
struct pe_raw_coff_strtbl cst;
};
int mdso_objgen_symentry(
const struct mdso_driver_ctx * dctx,
const char * sym,
struct mdso_object * vobj)
{
struct mdso_symentry_object * syment;
struct pe_raw_coff_symbol * symrec;
void * addr;
void * mark;
char * ch;
char * strtbl;
struct pe_raw_aux_rec_section * aux;
size_t liblen;
uint32_t symlen;
size_t cstlen;
uint32_t objlen;
uint32_t aattr;
uint32_t sattr;
uint32_t rattr;
uint16_t oattr;
uint16_t machine;
uint16_t reltype;
uint32_t relrva;
uint32_t refoff;
uint32_t reloff;
uint32_t symoff;
uint32_t uscore;
uint32_t stroff;
uint32_t stroff_cstdata;
uint32_t stroff_file;
uint32_t stroff_dsosyms;
uint32_t stroff_dsostrs;
uint32_t stroff_symstr;
uint32_t stroff_impsym;
uint32_t stroff_libname;
uint32_t stroff_null;
if ((symlen = (uint32_t)strlen(sym)) > 1024*1024)
return MDSO_CUSTOM_ERROR(dctx,MDSO_ERR_INVALID_DATA);
if ((liblen = strlen(dctx->cctx->libname)) > 1024*1024)
return MDSO_CUSTOM_ERROR(dctx,MDSO_ERR_INVALID_DATA);
stroff_cstdata = offsetof(struct pe_raw_coff_strtbl,cst_data);
stroff_file = stroff_cstdata;
stroff_dsosyms = stroff_file + 13 + symlen; /* .foo_symentry.s */
stroff_dsostrs = stroff_dsosyms + 10 + symlen; /* .dsosyms$foo */
stroff_symstr = stroff_dsostrs + 10 + symlen; /* .dsostrs$foo */
stroff_impsym = stroff_symstr + 9 + symlen; /* .symstr_foo */
stroff_libname = stroff_impsym + 8 + symlen; /* __imp__foo */
stroff_null = stroff_libname + 10 + liblen; /* .dsometa_libname */
stroff = offsetof(struct mdso_symentry_object,cst) + stroff_null;
stroff += 0xf;
stroff |= 0xf;
stroff ^= 0xf;
cstlen = stroff_null;
objlen = stroff + symlen + 1;
uscore = !(dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR);
if (vobj->addr && (vobj->size < objlen))
return MDSO_BUFFER_ERROR(dctx);
if ((addr = vobj->addr)) {
(void)0;
} else {
vobj->size = objlen;
vobj->mapstrsnum = 1;
vobj->mapstrslen = 7 + uscore + symlen;
if (!vobj->name)
return 0;
else if (mdso_create_object(dctx,vobj) < 0)
return MDSO_NESTED_ERROR(dctx);
}
syment = (struct mdso_symentry_object *)vobj->addr;
if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
aattr = PE_IMAGE_SCN_ALIGN_16BYTES;
machine = PE_IMAGE_FILE_MACHINE_AMD64;
reltype = PE_IMAGE_REL_AMD64_ADDR32NB;
relrva = 8;
} else {
aattr = PE_IMAGE_SCN_ALIGN_4BYTES;
machine = PE_IMAGE_FILE_MACHINE_I386;
reltype = PE_IMAGE_REL_I386_DIR32NB;
relrva = 4;
}
sattr = PE_IMAGE_SCN_ALIGN_1BYTES;
sattr |= PE_IMAGE_SCN_MEM_READ;
sattr |= PE_IMAGE_SCN_CNT_INITIALIZED_DATA;
sattr |= PE_IMAGE_SCN_LNK_COMDAT;
rattr = aattr;
rattr |= PE_IMAGE_SCN_MEM_READ;
rattr |= PE_IMAGE_SCN_CNT_INITIALIZED_DATA;
rattr |= PE_IMAGE_SCN_LNK_COMDAT;
oattr = PE_IMAGE_FILE_LINE_NUMS_STRIPPED;
refoff = offsetof(struct mdso_symentry_object,ref);
reloff = offsetof(struct mdso_symentry_object,rel);
symoff = offsetof(struct mdso_symentry_object,sym);
/* coff object header */
mdso_obj_write_short(syment->hdr.cfh_machine,machine);
mdso_obj_write_short(syment->hdr.cfh_num_of_sections,2);
mdso_obj_write_long(syment->hdr.cfh_ptr_to_sym_tbl,symoff);
mdso_obj_write_long(syment->hdr.cfh_num_of_syms,9);
mdso_obj_write_short(syment->hdr.cfh_characteristics,oattr);
/* .dsostrs section header */
sprintf((char *)syment->sec[0].sh_name,"/%d",stroff_dsostrs);
mdso_obj_write_long(syment->sec[0].sh_size_of_raw_data,symlen+1);
mdso_obj_write_long(syment->sec[0].sh_ptr_to_raw_data,stroff);
mdso_obj_write_long(syment->sec[0].sh_characteristics,sattr);
/* .dsosyms section header */
sprintf((char *)syment->sec[1].sh_name,"/%d",stroff_dsosyms);
mdso_obj_write_long(syment->sec[1].sh_size_of_raw_data,2*relrva);
mdso_obj_write_long(syment->sec[1].sh_ptr_to_raw_data,refoff);
mdso_obj_write_long(syment->sec[1].sh_ptr_to_relocs,reloff);
mdso_obj_write_short(syment->sec[1].sh_num_of_relocs,2);
mdso_obj_write_long(syment->sec[1].sh_characteristics,rattr);
/* .dsosyms relocation record: .symstr */
mdso_obj_write_long(syment->rel[0].rel_sym,6);
mdso_obj_write_long(syment->rel[0].rel_rva,0);
mdso_obj_write_short(syment->rel[0].rel_type,reltype);
/* .dsosyms relocation record: .dsometa_libname */
mdso_obj_write_long(syment->rel[1].rel_sym,8);
mdso_obj_write_long(syment->rel[1].rel_rva,relrva);
mdso_obj_write_short(syment->rel[1].rel_type,reltype);
/* coff string table */
mdso_obj_write_long(syment->cst.cst_size,cstlen);
mark = &syment->cst;
strtbl = mark;
/* coff symbol table */
symrec = syment->sym;
/* coff symbol: .file */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_FILE;
symrec[0].cs_num_of_aux_symbols[0] = 1;
mdso_obj_write_short(&symrec[0].cs_section_number[0],PE_IMAGE_SYM_DEBUG);
mdso_obj_write_long(&symrec[1].cs_name[4],stroff_file);
memcpy(symrec[0].cs_name,".file",5);
sprintf(&strtbl[stroff_file],".%s_symentry.s",sym);
symrec += 2;
/* coff symbol: .dsostrs */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
symrec[0].cs_num_of_aux_symbols[0] = 1;
mdso_obj_write_short(symrec[0].cs_section_number,1);
mdso_obj_write_long(&symrec[0].cs_name[4],stroff_dsostrs);
sprintf(&strtbl[stroff_dsostrs],"%s$%s",MDSO_STRS_SECTION,sym);
aux = (struct pe_raw_aux_rec_section *)&symrec[1];
mdso_obj_write_long(aux->aux_size,symlen+1);
mdso_obj_write_short(aux->aux_num_of_relocs,0);
symrec += 2;
/* coff symbol: .dsosyms */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
symrec[0].cs_num_of_aux_symbols[0] = 1;
mdso_obj_write_short(symrec[0].cs_section_number,2);
mdso_obj_write_long(&symrec[0].cs_name[4],stroff_dsosyms);
sprintf(&strtbl[stroff_dsosyms],"%s$%s",MDSO_SYMS_SECTION,sym);
aux = (struct pe_raw_aux_rec_section *)&symrec[1];
mdso_obj_write_long(aux->aux_size,2*relrva);
mdso_obj_write_short(aux->aux_num_of_relocs,2);
symrec += 2;
/* coff symbol: .symstr */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
symrec[0].cs_num_of_aux_symbols[0] = 0;
mdso_obj_write_short(symrec[0].cs_section_number,1);
mdso_obj_write_long(&symrec[0].cs_name[4],stroff_symstr);
sprintf(&strtbl[stroff_symstr],".symstr_%s",sym);
symrec += 1;
/* coff symbol: __imp_sym */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_EXTERNAL;
symrec[0].cs_num_of_aux_symbols[0] = 0;
mdso_obj_write_short(symrec[0].cs_section_number,2);
mdso_obj_write_long(&symrec[0].cs_name[4],stroff_impsym);
sprintf(&strtbl[stroff_impsym],"__imp_%s%s",uscore ? "_" : "", sym);
symrec += 1;
/* archive symbol map */
if (vobj->mapstrs)
strcpy(vobj->mapstrs,&strtbl[stroff_impsym]);
/* coff symbol: .dsometa_libname */
symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_EXTERNAL;
symrec[0].cs_num_of_aux_symbols[0] = 0;
mdso_obj_write_short(symrec[0].cs_section_number,0);
mdso_obj_write_long(&symrec[0].cs_name[4],stroff_libname);
sprintf(&strtbl[stroff_libname],"%s_%s",
MDSO_META_SECTION,
dctx->cctx->libname);
/* .symstr */
mark = syment;
ch = mark;
memcpy(&ch[stroff],sym,symlen);
/* fs object unmap */
if (!addr)
munmap(vobj->addr,vobj->size);
/* tada */
return 0;
}
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