mirror of
https://github.com/jart/cosmopolitan.git
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f4f4caab0e
I wanted a tiny scriptable meltdown proof way to run userspace programs and visualize how program execution impacts memory. It helps to explain how things like Actually Portable Executable works. It can show you how the GCC generated code is going about manipulating matrices and more. I didn't feel fully comfortable with Qemu and Bochs because I'm not smart enough to understand them. I wanted something like gVisor but with much stronger levels of assurances. I wanted a single binary that'll run, on all major operating systems with an embedded GPL barrier ZIP filesystem that is tiny enough to transpile to JavaScript and run in browsers too. https://justine.storage.googleapis.com/emulator625.mp4
228 lines
9 KiB
C
228 lines
9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/safemacros.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/stat.h"
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#include "libc/conv/conv.h"
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#include "libc/nt/struct/imagentheaders.h"
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#include "libc/nt/struct/imageoptionalheader.h"
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#include "libc/pe.h"
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#include "libc/stdio/stdio.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/prot.h"
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#include "third_party/xed/x86.h"
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#include "tool/decode/lib/asmcodegen.h"
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#include "tool/decode/lib/flagger.h"
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#include "tool/decode/lib/peidnames.h"
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#include "tool/decode/lib/titlegen.h"
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/**
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* @fileoverview Portable executable metadata disassembler.
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* @see https://www.aldeid.com/wiki/PE-Portable-executable
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*/
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static const char *path;
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static struct NtImageDosHeader *mz;
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static size_t mzsize;
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static struct XedDecodedInst *ildreal(void *addr) {
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static struct XedDecodedInst xedd;
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if (xed_instruction_length_decode(
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xed_decoded_inst_zero_set_mode(&xedd, XED_MACHINE_MODE_REAL), addr,
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XED_MAX_INSTRUCTION_BYTES) != XED_ERROR_NONE ||
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!xedd.length) {
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xedd.length = 1;
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}
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return &xedd;
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}
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static void startfile(void) {
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showtitle("αcτµαlly pδrταblε εxεcµταblε", "tool/decode/pe", NULL, NULL,
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&kModelineAsm);
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printf("#include \"libc/pe.h\"\n\n", path);
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}
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static void showmzheader(void) {
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showtitle(basename(path), "dos", "mz header",
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"\tMZ = Mark 'Zibo' Joseph Zbikowski\n"
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"\te_cblp: bytes on last page\n"
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"\te_cp: 512-byte pages in file\n"
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"\te_crlc: reloc table entry count\n"
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"\te_cparhdr: data segment file offset / 16\n"
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"\te_{min,max}alloc: lowers upper bound load / 16\n"
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"\te_ss: lower bound on stack segment\n"
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"\te_sp: initialize stack pointer\n"
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"\te_csum: ∑bₙ checksum don't bother\n"
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"\te_ip: initial ip value\n"
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"\te_cs: increases cs load lower bound\n"
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"\te_lfarlc: reloc table offset\n"
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"\te_ovno: overlay number\n"
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"\te_lfanew: portable executable header rva",
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NULL);
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printf("\n");
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show(".ascii", format(b1, "%`'.*s", 2, (const char *)&mz->e_magic),
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"mz->e_magic");
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showshorthex(mz->e_cblp);
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showshorthex(mz->e_cp);
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showshorthex(mz->e_crlc);
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showshorthex(mz->e_cparhdr);
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showshorthex(mz->e_minalloc);
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showshorthex(mz->e_maxalloc);
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showshorthex(mz->e_ss);
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showshorthex(mz->e_sp);
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showshorthex(mz->e_csum);
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showshorthex(mz->e_ip);
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showshorthex(mz->e_cs);
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showshorthex(mz->e_lfarlc);
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showshorthex(mz->e_ovno);
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show(".short",
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format(b1, "%hn,%hn,%hn,%hn", mz->e_res[0], mz->e_res[1], mz->e_res[2],
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mz->e_res[3]),
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"mz->e_res");
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showshorthex(mz->e_oemid);
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showshorthex(mz->e_oeminfo);
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show(".short",
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format(b1, "%hn,%hn,%hn,%hn,%hn,%hn,%hn,%hn,%hn,%hn", mz->e_res2[0],
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mz->e_res2[1], mz->e_res2[2], mz->e_res2[3], mz->e_res2[4],
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mz->e_res2[5], mz->e_res2[6], mz->e_res2[7], mz->e_res2[8],
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mz->e_res2[9]),
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"mz->e_res2");
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showinthex(mz->e_lfanew);
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printf("\n");
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}
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static void showdosstub(void) {
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unsigned char *p = (unsigned char *)mz + sizeof(struct NtImageDosHeader);
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unsigned char *pe = (mz->e_lfanew ? p + mz->e_lfanew : p + mzsize);
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pe = min(pe, p + mzsize - XED_MAX_INSTRUCTION_BYTES);
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while (p < pe) {
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struct XedDecodedInst *inst = ildreal(p);
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if (p + inst->length > pe) break;
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printf("\t.byte\t");
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for (unsigned i = 0; i < inst->length; ++i) {
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if (i) printf(",");
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printf("%#hhx", inst->bytes[i]);
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}
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printf("\n");
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p += inst->length;
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}
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printf("\n");
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}
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static void showpeoptionalheader(struct NtImageOptionalHeader *opt) {
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showtitle(basename(path), "windows", "pe \"optional\" header", NULL, NULL);
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printf("\n");
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show(".short",
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firstnonnull(findnamebyid(kNtPeOptionalHeaderMagicNames, opt->Magic),
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format(b1, "%#hx", opt->Magic)),
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"opt->Magic");
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showint(opt->MajorLinkerVersion);
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showint(opt->MinorLinkerVersion);
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showinthex(opt->SizeOfCode);
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showinthex(opt->SizeOfInitializedData);
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showinthex(opt->SizeOfUninitializedData);
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showinthex(opt->AddressOfEntryPoint);
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showinthex(opt->BaseOfCode);
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showint64hex(opt->ImageBase);
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showinthex(opt->SectionAlignment);
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showinthex(opt->FileAlignment);
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showshort(opt->MajorOperatingSystemVersion);
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showshort(opt->MinorOperatingSystemVersion);
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showshort(opt->MajorImageVersion);
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showshort(opt->MinorImageVersion);
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showshort(opt->MajorSubsystemVersion);
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showshort(opt->MinorSubsystemVersion);
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showint(opt->Win32VersionValue);
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showinthex(opt->SizeOfImage);
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showinthex(opt->SizeOfHeaders);
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showinthex(opt->CheckSum);
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show(".short",
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firstnonnull(findnamebyid(kNtImageSubsystemNames, opt->Subsystem),
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format(b1, "%#hx", opt->Subsystem)),
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"opt->Subsystem");
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show(".short",
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firstnonnull(RecreateFlags(kNtImageDllcharacteristicNames,
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opt->DllCharacteristics),
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format(b1, "%#hx", opt->DllCharacteristics)),
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"opt->DllCharacteristics");
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showint64hex(opt->SizeOfStackReserve);
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showint64hex(opt->SizeOfStackCommit);
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showint64hex(opt->SizeOfHeapReserve);
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showint64hex(opt->SizeOfHeapCommit);
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showinthex(opt->LoaderFlags);
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showinthex(opt->NumberOfRvaAndSizes);
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}
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static void showpeheader(struct NtImageNtHeaders *pe) {
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showtitle(basename(path), "windows", "pe header", NULL, NULL);
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printf("\n");
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showorg(mz->e_lfanew);
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show(".ascii", format(b1, "%`'.*s", 4, (const char *)&pe->Signature),
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"pe->Signature");
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show(".short",
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firstnonnull(
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findnamebyid(kNtImageFileMachineNames, pe->FileHeader.Machine),
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format(b1, "%#hx", pe->FileHeader.Machine)),
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"pe->FileHeader.Machine");
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showshort(pe->FileHeader.NumberOfSections);
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showinthex(pe->FileHeader.TimeDateStamp);
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showinthex(pe->FileHeader.PointerToSymbolTable);
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showint(pe->FileHeader.NumberOfSymbols);
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showshort(pe->FileHeader.SizeOfOptionalHeader);
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show(".short",
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firstnonnull(RecreateFlags(kNtImageCharacteristicNames,
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pe->FileHeader.Characteristics),
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format(b1, "%#hx", pe->FileHeader.Characteristics)),
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"pe->FileHeader.Characteristics");
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printf("\n");
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showpeoptionalheader(pecheckaddress(mz, mzsize, &pe->OptionalHeader,
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pe->FileHeader.SizeOfOptionalHeader));
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}
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static void showall(void) {
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startfile();
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showmzheader();
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showdosstub();
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if (mz->e_lfanew) {
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showpeheader(pecomputerva(mz, mzsize, mz->e_lfanew,
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sizeof(struct NtImageFileHeader)));
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}
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}
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int main(int argc, char *argv[]) {
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int64_t fd;
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struct stat st[1];
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if (argc != 2) fprintf(stderr, "usage: %s FILE\n", argv[0]), exit(1);
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if ((fd = open((path = argv[1]), O_RDONLY)) == -1 || fstat(fd, st) == -1 ||
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(mz = mmap(NULL, (mzsize = st->st_size), PROT_READ, MAP_SHARED, fd, 0)) ==
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MAP_FAILED) {
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fprintf(stderr, "error: %'s %m\n", path);
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exit(1);
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}
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if (mz->e_magic != kNtImageDosSignature) {
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fprintf(stderr, "error: %'s not a dos executable\n", path);
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exit(1);
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}
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showall();
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munmap(mz, mzsize);
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close(fd);
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return 0;
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}
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