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Get fork() working on Windows

Browse source 
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

146
libc/stdio/system.c
View file

@ -19,126 +19,12 @@
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/mem/mem.h"
#include "libc/nt/accounting.h"
#include "libc/nt/enum/startf.h"
#include "libc/nt/enum/status.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/processinformation.h"
#include "libc/nt/synchronization.h"
#include "libc/calls/hefty/spawn.h"
#include "libc/dce.h"
#include "libc/paths.h"
#include "libc/runtime/missioncritical.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/fileno.h"
#include "libc/sysv/errfuns.h"
#define SHELL_BIN "/bin/sh"
#define SHELL_ARG "-c"
#define CMD_C "CMD /C "
static int system$sysv(const char *cmdline) {
int rc, n, wstatus;
struct mem {
char shell[sizeof(SHELL_BIN)];
char arg[sizeof(SHELL_ARG)];
char *args[4];
char cmdline[];
} * mem;
if (cmdline != NULL) {
mem = malloc(sizeof(struct mem) + (strlen(cmdline) + 1));
if (!mem) return enomem();
strcpy(mem->shell, SHELL_BIN);
strcpy(mem->arg, SHELL_ARG);
mem->args[0] = mem->shell;
mem->args[1] = mem->arg;
mem->args[2] = mem->cmdline;
mem->args[3] = NULL;
strcpy(mem->cmdline, cmdline);
if ((rc = vfork()) != -1) {
if (rc == 0) {
execve$sysv(mem->shell, mem->args, environ);
abort();
}
if ((rc = wait4$sysv(rc, &wstatus, 0, NULL)) != -1) {
rc = wstatus;
}
}
free(mem);
return rc;
} else {
return fileexists(SHELL_BIN);
}
}
static textwindows noinline int system$nt(const char *cmdline) {
char *mem;
int rc, status;
uint32_t dwExitCode;
struct NtStartupInfo startinfo;
struct NtProcessInformation *info;
uint16_t *cmdline16, *quotedcmdline16;
unsigned len, dosquotemultiplier, cmdline16bytes, quotedcmdline16bytes;
if (cmdline != NULL) {
rc = -1;
dosquotemultiplier = 2;
len = strlen(cmdline);
cmdline16bytes = (len + 1) * sizeof(uint16_t);
quotedcmdline16bytes =
strlen(CMD_C) * sizeof(uint16_t) + cmdline16bytes * dosquotemultiplier;
if (!(mem = malloc(sizeof(struct NtProcessInformation) + cmdline16bytes +
quotedcmdline16bytes))) {
return enomem();
}
info = (struct NtProcessInformation *)mem;
cmdline16 = (uint16_t *)(mem + sizeof(struct NtProcessInformation));
quotedcmdline16 = (uint16_t *)(mem + sizeof(struct NtProcessInformation) +
cmdline16bytes);
strcpyzbw(cmdline16, cmdline);
strcpyzbw(quotedcmdline16, CMD_C);
if (escapedos(quotedcmdline16 + strlen(CMD_C), len * dosquotemultiplier,
cmdline16, len)) {
memset(&startinfo, 0, sizeof(startinfo));
startinfo.cb = sizeof(struct NtStartupInfo);
startinfo.dwFlags = kNtStartfUsestdhandles;
startinfo.hStdInput = STDIN_FILENO;
startinfo.hStdOutput = STDOUT_FILENO;
startinfo.hStdError = STDERR_FILENO;
if (CreateProcess(
/* lpApplicationName */ NULL,
/* lpCommandLine */ quotedcmdline16,
/* lpProcessAttributes */ NULL,
/* lpThreadAttributes */ NULL,
/* bInheritHandles */ true,
/* dwCreationFlags */ kNtCreateNoWindow,
/* lpEnvironment */ NULL,
/* lpCurrentDirectory */ NULL,
/* lpStartupInfo */ &startinfo,
/* lpProcessInformation */ info)) {
dwExitCode = kNtStillActive;
do {
WaitForSingleObject(info->hProcess, 0xffffffff);
} while ((status = GetExitCodeProcess(info->hProcess, &dwExitCode)) &&
dwExitCode == kNtStillActive);
if (weaken(fflush)) {
weaken(fflush)(*weaken(stderr));
}
rc = (dwExitCode & 0xff) << 8; /* @see WEXITSTATUS() */
CloseHandle(info->hProcess);
CloseHandle(info->hThread);
} else {
rc = winerr();
}
} else {
rc = einval();
}
free(mem);
return rc;
} else {
/* how could cmd.exe not exist? */
return true;
}
}
/**
* Launches program with system command interpreter.
@ -148,12 +34,24 @@ static textwindows noinline int system$nt(const char *cmdline) {
* status that can be accessed using macros like WEXITSTATUS(s)
*/
int system(const char *cmdline) {
int rc;
const char *prog, *arg;
int rc, wstatus, fds[3];
if (weaken(fflush)) weaken(fflush)(NULL);
if (!IsWindows()) {
rc = system$sysv(cmdline);
if (cmdline) {
prog = !IsWindows() ? _PATH_BSHELL : "cmd";
arg = !IsWindows() ? "-c" : "/C";
fds[0] = 0;
fds[1] = 1;
fds[2] = 2;
if ((rc = spawnlp(0, fds, prog, prog, arg, cmdline, NULL)) != -1) {
if ((rc = wait4(rc, &wstatus, 0, NULL)) != -1) {
rc = wstatus;
}
}
return rc;
} else if (IsWindows()) {
return true;
} else {
rc = system$nt(cmdline);
return fileexists(_PATH_BSHELL);
}
return rc;
}