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Get fork() working on Windows

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This is done without using Microsoft's internal APIs. MAP_PRIVATE
mappings are copied to the subprocess via a pipe, since Microsoft
doesn't want us to have proper COW pages. MAP_SHARED mappings are
remapped without needing to do any copying. Global variables need
copying along with the stack and the whole heap of anonymous mem.
This actually improves the reliability of the redbean http server
although one shouldn't expect 10k+ connections on a home computer
that isn't running software built to serve like Linux or FreeBSD.
This commit is contained in:
Justine Tunney 2020-11-13 01:27:49 -08:00
parent aea89fe832
commit db33973e0a
105 changed files with 1476 additions and 912 deletions
Download patch file Download diff file Expand all files Collapse all files

106
libc/runtime/winmain.greg.c
View file

@ -20,7 +20,10 @@
#include "libc/bits/bits.h"
#include "libc/bits/pushpop.h"
#include "libc/bits/weaken.h"
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/fmt/fmt.h"
#include "libc/macros.h"
#include "libc/nt/console.h"
#include "libc/nt/enum/consolemodeflags.h"
#include "libc/nt/enum/filetype.h"
@ -34,8 +37,21 @@
#include "libc/nt/struct/teb.h"
#include "libc/runtime/getdosenviron.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/memtrack.h"
#include "libc/runtime/missioncritical.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/winmain.h"
#include "libc/sock/internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
struct WinArgs {
char *argv[512];
char *envp[512];
long auxv[1][2];
char argblock[ARG_MAX];
char envblock[ENV_MAX];
};
static struct CmdExe {
bool result;
@ -46,13 +62,7 @@ static struct CmdExe {
} oldin, oldout;
} g_cmdexe;
static textwindows void MitigateDriveByDownloads(void) {
unsigned wrote;
if (!SetDefaultDllDirectories(kNtLoadLibrarySearchSearchSystem32)) {
WriteFile(GetStdHandle(kNtStdErrorHandle), "nodll\n", 6, &wrote, NULL);
ExitProcess(1);
}
}
struct WinMain g_winmain;
static textwindows void RestoreCmdExe(void) {
if (g_cmdexe.oldin.handle) {
@ -104,6 +114,53 @@ static textwindows void NormalizeCmdExe(void) {
}
}
static textwindows char *AllocateMemory(void *addr, size_t size, int64_t *h) {
return MapViewOfFileExNuma(
(*h = CreateFileMappingNuma(-1, NULL, pushpop(kNtPageReadwrite), 0, size,
NULL, kNtNumaNoPreferredNode)),
kNtFileMapRead | kNtFileMapWrite, 0, 0, size, addr,
kNtNumaNoPreferredNode);
}
static textwindows noreturn void WinMainNew(int64_t hInstance,
int64_t hPrevInstance,
const char *lpCmdLine,
int nCmdShow) {
int64_t h;
size_t size;
int i, count;
uint64_t data;
struct WinArgs *wa;
const char16_t *env16;
g_winmain.nCmdShow = nCmdShow;
g_winmain.hInstance = hInstance;
g_winmain.hPrevInstance = hPrevInstance;
NormalizeCmdExe();
*(/*unconst*/ int *)&hostos = WINDOWS;
size = ROUNDUP(STACKSIZE + sizeof(struct WinArgs), FRAMESIZE);
data = 0x777000000000;
data = (intptr_t)AllocateMemory((char *)data, size, &_mmi.p[0].h);
_mmi.p[0].x = data >> 16;
_mmi.p[0].y = (data >> 16) + ((size >> 16) - 1);
_mmi.p[0].prot = PROT_READ | PROT_WRITE;
_mmi.p[0].flags = MAP_PRIVATE | MAP_ANONYMOUS;
_mmi.i = pushpop(1L);
wa = (struct WinArgs *)(data + size - sizeof(struct WinArgs));
count = GetDosArgv(GetCommandLine(), wa->argblock, ARG_MAX, wa->argv, 512);
for (i = 0; wa->argv[0][i]; ++i) {
if (wa->argv[0][i] == '\\') {
wa->argv[0][i] = '/';
}
}
env16 = GetEnvironmentStrings();
GetDosEnviron(env16, wa->envblock, ENV_MAX, wa->envp, 512);
FreeEnvironmentStrings(env16);
wa->auxv[0][0] = pushpop(0L);
wa->auxv[0][1] = pushpop(0L);
_jmpstack((char *)data + STACKSIZE, _executive, count, wa->argv, wa->envp,
wa->auxv);
}
/**
* Main function on Windows NT.
*
@ -130,30 +187,15 @@ static textwindows void NormalizeCmdExe(void) {
* the downloads folder. Since we don't even use dynamic linking,
* we've cargo culted some API calls, that may harden against it.
*
* 6. Finally, we need fork. Microsoft designed Windows to prevent us
* from having fork() so we pass pipe handles in an environment
* variable literally copy all the memory.
*
*/
textwindows int WinMain(void *hInstance, void *hPrevInstance,
const char *lpCmdLine, int nCmdShow) {
char *stack;
int i, count;
const char16_t *cmd16, *env16;
char *argv[512], *envp[512];
char argblock[ARG_MAX], envblock[ENV_MAX];
long auxv[][2] = {{pushpop(0L), pushpop(0L)}};
MitigateDriveByDownloads();
NormalizeCmdExe();
*(/*unconst*/ int *)&hostos = WINDOWS;
cmd16 = GetCommandLine();
env16 = GetEnvironmentStrings();
count = GetDosArgv(cmd16, argblock, ARG_MAX, argv, 512);
for (i = 0; argv[0][i]; ++i) {
if (argv[0][i] == '\\') argv[0][i] = '/';
}
GetDosEnviron(env16, envblock, ENV_MAX, envp, 512);
FreeEnvironmentStrings(env16);
stack = MapViewOfFileExNuma(
CreateFileMappingNuma(-1, NULL, pushpop(kNtPageReadwrite), 0, STACKSIZE,
NULL, kNtNumaNoPreferredNode),
kNtFileMapRead | kNtFileMapWrite, 0, 0, STACKSIZE,
(char *)0x777000000000 - STACKSIZE, kNtNumaNoPreferredNode);
return _setstack(stack + STACKSIZE, _executive, count, argv, envp, auxv);
textwindows int64_t WinMain(int64_t hInstance, int64_t hPrevInstance,
const char *lpCmdLine, int nCmdShow) {
SetDefaultDllDirectories(kNtLoadLibrarySearchSearchSystem32);
if (weaken(winsockinit)) weaken(winsockinit)();
if (weaken(WinMainForked)) weaken(WinMainForked)();
WinMainNew(hInstance, hPrevInstance, lpCmdLine, nCmdShow);
}