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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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13
libc/runtime/piro.c
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@@ -33,17 +33,16 @@
╠──────────────────────────────────────────────────────▌▀▄─▐──▀▄─▐▄─▐▄▐▄─▐▄─▐▄─│
│ αcτµαlly pδrταblε εxεcµταblε § post-initialization read-only │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/bits/safemacros.h"
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/dce.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/prot.h"
#define getaddr(section) ((intptr_t)weakaddr(section))
static textstartup void __piro_protect(intptr_t start, intptr_t end, int prot) {
static textstartup void _piro_protect(intptr_t start, intptr_t end, int prot) {
ssize_t len = end - start;
if (len > 0 && start && start % PAGESIZE == 0 && len % PAGESIZE == 0) {
if (mprotect((void *)(unsigned long)start, len, prot) == -1) abort();
@@ -62,10 +61,10 @@ static textstartup void __piro_protect(intptr_t start, intptr_t end, int prot) {
* @see ape/ape.lds
* @see libc/_start.S
*/
textstartup void __piro(int prot) {
textstartup void _piro(int prot) {
if (getaddr("main") < getaddr("__test_start")) {
__piro_protect(getaddr("__test_start"), getaddr("__test_end"), PROT_NONE);
_piro_protect(getaddr("__test_start"), getaddr("__test_end"), PROT_NONE);
}
__piro_protect(getaddr("__ro"), getaddr("_etext"), PROT_READ);
__piro_protect(getaddr("__piro_start"), getaddr("__piro_end"), prot);
_piro_protect(getaddr("__ro"), getaddr("_etext"), PROT_READ);
_piro_protect(getaddr("__piro_start"), getaddr("__piro_end"), prot);
}