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-rw-r--r--src/object/mdso_objgen_symfn.c226
1 files changed, 226 insertions, 0 deletions
diff --git a/src/object/mdso_objgen_symfn.c b/src/object/mdso_objgen_symfn.c
new file mode 100644
index 0000000..5644f4c
--- /dev/null
+++ b/src/object/mdso_objgen_symfn.c
@@ -0,0 +1,226 @@
+/****************************************************************/
+/* mdso: midipix dso scavenger */
+/* Copyright (C) 2015--2017 Z. Gilboa */
+/* Released under GPLv2 and GPLv3; see COPYING.MDSO. */
+/****************************************************************/
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <mdso/mdso.h>
+#include "mdso_object_impl.h"
+#include "mdso_errinfo_impl.h"
+#include "perk_consts.h"
+#include "perk_structs.h"
+
+static const unsigned char jmp_code_i386[16] = {
+ 0xff,0x25,
+ 0x0,0x0,0x0,0x0,
+ 0x90,0x90,
+ 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0
+};
+
+static const unsigned char jmp_code_amd64[16] = {
+ 0xff,0x24,0x25,
+ 0x0,0x0,0x0,0x0,
+ 0x90,
+ 0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90
+};
+
+struct mdso_symfn_code {
+ unsigned char code[16];
+};
+
+struct mdso_symfn_object {
+ struct pe_raw_coff_object_hdr hdr;
+ struct pe_raw_sec_hdr sec[1];
+ struct mdso_symfn_code cod[1];
+ struct pe_raw_coff_reloc rel[1];
+ struct pe_raw_coff_symbol sym[7];
+ struct pe_raw_coff_strtbl cst;
+};
+
+int mdso_objgen_symfn(
+ const struct mdso_driver_ctx * dctx,
+ const char * sym,
+ FILE * fout,
+ struct mdso_object * vobj)
+{
+ struct mdso_symfn_object * symfn;
+ struct pe_raw_coff_symbol * symrec;
+ const unsigned char * code;
+ unsigned char * mark;
+ struct pe_aux_rec_section * aux;
+ size_t buflen;
+ uint32_t symlen;
+ uint32_t cstlen;
+ uint32_t objlen;
+ uint32_t aattr;
+ uint32_t sattr;
+ uint16_t oattr;
+ uint16_t machine;
+ uint16_t reltype;
+ uint32_t relrva;
+ uint32_t reloff;
+ uint32_t symoff;
+ uint32_t cstoff;
+ uint32_t codoff;
+ uint32_t datoff;
+
+ if ((buflen = strlen(sym)) > 1024*1024)
+ return MDSO_CUSTOM_ERROR(dctx,MDSO_ERR_INVALID_DATA);
+
+ symlen = (uint32_t)buflen;
+ cstlen = (3 * symlen) + 32;
+ objlen = sizeof(*symfn) + cstlen;
+
+ if (vobj && vobj->addr && (vobj->size < objlen))
+ return MDSO_BUFFER_ERROR(dctx);
+
+ if (vobj && !vobj->addr) {
+ vobj->size = objlen;
+ return 0;
+ }
+
+ if (vobj)
+ symfn = (struct mdso_symfn_object *)vobj->addr;
+
+ else if (!(symfn = calloc(1,objlen)))
+ return MDSO_SYSTEM_ERROR(dctx);
+
+ if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
+ code = jmp_code_amd64;
+ aattr = PE_IMAGE_SCN_ALIGN_16BYTES;
+ machine = PE_IMAGE_FILE_MACHINE_AMD64;
+ reltype = PE_IMAGE_REL_AMD64_ADDR32;
+ relrva = 3;
+ } else {
+ code = jmp_code_i386;
+ aattr = PE_IMAGE_SCN_ALIGN_4BYTES;
+ machine = PE_IMAGE_FILE_MACHINE_I386;
+ reltype = PE_IMAGE_REL_I386_DIR32;
+ relrva = 2;
+ }
+
+ sattr = aattr;
+ sattr |= PE_IMAGE_SCN_MEM_READ;
+ sattr |= PE_IMAGE_SCN_MEM_EXECUTE;
+ sattr |= PE_IMAGE_SCN_CNT_CODE;
+
+ oattr = PE_IMAGE_FILE_LINE_NUMS_STRIPPED;
+ reloff = offsetof(struct mdso_symfn_object,rel);
+ symoff = offsetof(struct mdso_symfn_object,sym);
+ codoff = offsetof(struct mdso_symfn_object,cod);
+ cstoff = offsetof(struct pe_raw_coff_strtbl,cst_data);
+ datoff = 0;
+
+ /* coff object header */
+ mdso_obj_write_short(symfn->hdr.cfh_machine,machine);
+ mdso_obj_write_short(symfn->hdr.cfh_num_of_sections,1);
+ mdso_obj_write_long(symfn->hdr.cfh_ptr_to_sym_tbl,symoff);
+ mdso_obj_write_long(symfn->hdr.cfh_num_of_syms,7);
+ mdso_obj_write_short(symfn->hdr.cfh_characteristics,oattr);
+
+ /* .text section header */
+ memcpy(symfn->sec[0].sh_name,".text",5);
+ mdso_obj_write_long(symfn->sec[0].sh_size_of_raw_data,16);
+ mdso_obj_write_long(symfn->sec[0].sh_ptr_to_raw_data,codoff);
+ mdso_obj_write_long(symfn->sec[0].sh_ptr_to_relocs,reloff);
+ mdso_obj_write_short(symfn->sec[0].sh_num_of_relocs,1);
+ mdso_obj_write_long(symfn->sec[0].sh_characteristics,sattr);
+
+ /* .text section content */
+ memcpy(symfn->cod,code,16);
+
+ /* .text relocation record */
+ mdso_obj_write_long(symfn->rel[0].rel_sym,6);
+ mdso_obj_write_long(symfn->rel[0].rel_rva,relrva);
+ mdso_obj_write_short(symfn->rel[0].rel_type,reltype);
+
+ /* coff string table */
+ mdso_obj_write_long(symfn->cst.cst_size,cstlen);
+
+ /* coff symbol table */
+ symrec = symfn->sym;
+ mark = symfn->cst.cst_data;
+
+ /* 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],cstoff+datoff);
+
+ memcpy(symrec[0].cs_name,".file",5);
+ memcpy(&mark[0],"__",2);
+ memcpy(&mark[2],sym,symlen);
+ memcpy(&mark[2+symlen],"_sym_fn.s",9);
+
+ datoff += 12 + symlen;
+ mark += 12 + symlen;
+ symrec += 2;
+
+ /* coff symbol: .text */
+ 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);
+ memcpy(symrec[0].cs_name,".text",5);
+
+ aux = (struct pe_aux_rec_section *)&symrec[1];
+ mdso_obj_write_long(aux->aux_size,relrva+4);
+ mdso_obj_write_short(aux->aux_num_of_relocs,1);
+
+ datoff += 0;
+ mark += 0;
+ symrec += 2;
+
+ /* coff symbol: sym */
+ symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_EXTERNAL;
+ symrec[0].cs_num_of_aux_symbols[0] = 1;
+
+ mdso_obj_write_short(symrec[0].cs_type,PE_IMAGE_SYM_DTYPE_FUNCTION<<8);
+ mdso_obj_write_short(symrec[0].cs_section_number,1);
+ mdso_obj_write_long(&symrec[0].cs_name[4],cstoff+datoff);
+
+ if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
+ memcpy(&mark[0],sym,symlen);
+ } else {
+ memcpy(&mark[1],sym,symlen);
+ mark[0] = '_';
+ datoff++;
+ mark++;
+ }
+
+ datoff += 1 + symlen;
+ mark += 1 + symlen;
+ symrec += 2;
+
+ /* 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,0);
+ mdso_obj_write_long(&symrec[0].cs_name[4],cstoff+datoff);
+
+ if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
+ memcpy(&mark[0],"__imp_",6);
+ memcpy(&mark[6],sym,symlen);
+ } else {
+ memcpy(&mark[0],"__imp_",6);
+ memcpy(&mark[7],sym,symlen);
+ mark[6] = '_';
+ datoff++;
+ mark++;
+ }
+
+ /* tada */
+ if (fout)
+ if (fwrite(symfn,objlen,1,fout) == 0)
+ return MDSO_FILE_ERROR(dctx);
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 23:29:22 +0000