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Add x86_64-linux-gnu emulator

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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
This commit is contained in:
Justine Tunney 2020-08-25 04:23:25 -07:00
parent 467504308a
commit f4f4caab0e
1052 changed files with 65667 additions and 7825 deletions
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21
tool/build/package.c
View file

@ -22,12 +22,11 @@
#include "libc/alg/bisect.h"
#include "libc/alg/bisectcarleft.h"
#include "libc/assert.h"
#include "libc/bits/bits.h"
#include "libc/bits/bswap.h"
#include "libc/bits/safemacros.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/conv/conv.h"
#include "libc/conv/sizemultiply.h"
#include "libc/elf/def.h"
#include "libc/elf/elf.h"
#include "libc/elf/struct/rela.h"
@ -143,7 +142,7 @@ struct Packages {
size_t i, n;
struct Op {
int32_t offset;
uint8_t decoded_length;
uint8_t length;
uint8_t pos_disp;
uint16_t __pad;
} * p;
@ -243,7 +242,7 @@ void GetOpts(struct Package *pkg, struct Packages *deps, int argc,
exit(1);
}
}
CHECK_NE(-1, pkg->path);
CHECK_NE(-1, pkg->path, "no packages passed to package.com");
CHECK_LT(optind, argc,
"no objects passed to package.com; "
"is your foo.mk $(FOO_OBJS) glob broken?");
@ -290,17 +289,16 @@ void IndexSections(struct Object *obj) {
}
if (shdr->sh_flags & SHF_EXECINSTR) {
CHECK_NOTNULL((code = getelfsectionaddress(obj->elf, obj->size, shdr)));
for (op.offset = 0; op.offset < shdr->sh_size;
op.offset += op.decoded_length) {
for (op.offset = 0; op.offset < shdr->sh_size; op.offset += op.length) {
if (xed_instruction_length_decode(
xed_decoded_inst_zero_set_mode(&xedd, XED_MACHINE_MODE_LONG_64),
&code[op.offset],
min(shdr->sh_size - op.offset, XED_MAX_INSTRUCTION_BYTES)) ==
XED_ERROR_NONE) {
op.decoded_length = xedd.decoded_length;
op.pos_disp = xedd.operands.pos_disp;
op.length = xedd.length;
op.pos_disp = xedd.op.pos_disp;
} else {
op.decoded_length = 1;
op.length = 1;
op.pos_disp = 0;
}
CHECK_NE(-1, append(&sect.ops, &op));
@ -484,11 +482,11 @@ void OptimizeRelocations(struct Package *pkg, struct Packages *deps,
op = &obj->sections.p[shdr->sh_info].ops.p[bisectcarleft(
(const int32_t(*)[2])obj->sections.p[shdr->sh_info].ops.p,
obj->sections.p[shdr->sh_info].ops.i, rela->r_offset)];
CHECK_GT(op->decoded_length, 4);
CHECK_GT(op->length, 4);
CHECK_GT(op->pos_disp, 0);
rela->r_info = ELF64_R_INFO(ELF64_R_SYM(rela->r_info), R_X86_64_32S);
rela->r_addend = -IMAGE_BASE_VIRTUAL + rela->r_addend +
(op->decoded_length - op->pos_disp);
(op->length - op->pos_disp);
code[rela->r_offset - 1] = ChangeRipToRbx(code[rela->r_offset - 1]);
}
#endif
@ -658,6 +656,7 @@ void Package(int argc, char *argv[], struct Package *pkg,
int main(int argc, char *argv[]) {
struct Package pkg;
struct Packages deps;
showcrashreports();
memset(&pkg, 0, sizeof(pkg));
memset(&deps, 0, sizeof(deps));
Package(argc, argv, &pkg, &deps);