mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-26 14:28:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Make execve() linger when it can't spoof parent

Browse source 
It's now possible to use execve() when the parent process isn't built by
cosmo. In such cases, the current process will kill all threads and then
linger around, waiting for the newly created process to die, and then we
propagate its exit code to the parent. This should help bazel and others

Allocating private anonymous memory is now 5x faster on Windows. This is
thanks to VirtualAlloc() which is faster than the file mapping APIs. The
fork() function also now goes 30% faster, since we are able to avoid the
VirtualProtect() calls on mappings in most cases now.

Fixes #1253
This commit is contained in:
Justine Tunney 2025-01-04 21:11:53 -08:00
parent c97a858470
commit 42a3bb729a
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
40 changed files with 612 additions and 656 deletions
Download patch file Download diff file Expand all files Collapse all files

43
libc/proc/fork-nt.c
View file

@ -46,6 +46,7 @@
#include "libc/nt/winsock.h"
#include "libc/proc/proc.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/symbols.internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
@ -211,8 +212,6 @@ textwindows static int sys_fork_nt_parent(uint32_t dwCreationFlags) {
// let's go
bool ok = true;
uint32_t child_old_protect;
uint32_t parent_old_protect;
// copy memory manager maps
for (struct MapSlab *slab =
@ -225,11 +224,12 @@ textwindows static int sys_fork_nt_parent(uint32_t dwCreationFlags) {
}
// copy private memory maps
int alloc_prot = -1;
for (struct Map *map = __maps_first(); map; map = __maps_next(map)) {
if ((map->flags & MAP_TYPE) == MAP_SHARED)
continue;
continue; // shared memory doesn't need to be copied to subprocess
if ((map->flags & MAP_NOFORK) && (map->flags & MAP_TYPE) != MAP_FILE)
continue;
continue; // ignore things like signal worker stack memory
if (__maps_isalloc(map)) {
size_t allocsize = map->size;
for (struct Map *m2 = __maps_next(map); m2; m2 = __maps_next(m2)) {
@ -240,22 +240,41 @@ textwindows static int sys_fork_nt_parent(uint32_t dwCreationFlags) {
}
}
if ((map->flags & MAP_NOFORK) && (map->flags & MAP_TYPE) == MAP_FILE) {
ok = ok && !!VirtualProtectEx(procinfo.hProcess, map->addr, allocsize,
kNtPageReadwrite, &child_old_protect);
// portable executable segment
if (!(map->prot & PROT_WRITE)) {
uint32_t child_old_protect;
ok = ok && !!VirtualProtectEx(procinfo.hProcess, map->addr, allocsize,
kNtPageReadwrite, &child_old_protect);
alloc_prot = PROT_READ | PROT_WRITE;
} else {
alloc_prot = map->prot;
}
} else {
// private mapping
uint32_t page_flags;
if (!(alloc_prot & PROT_WRITE)) {
page_flags = kNtPageReadwrite;
alloc_prot = PROT_READ | PROT_WRITE;
} else {
page_flags = __prot2nt(alloc_prot, false);
}
ok = ok && !!VirtualAllocEx(procinfo.hProcess, map->addr, allocsize,
kNtMemReserve | kNtMemCommit,
kNtPageExecuteReadwrite);
kNtMemReserve | kNtMemCommit, page_flags);
}
}
uint32_t parent_old_protect;
if (!(map->prot & PROT_READ))
ok = ok && !!VirtualProtect(map->addr, map->size, kNtPageReadwrite,
&parent_old_protect);
ok = ok && !!WriteProcessMemory(procinfo.hProcess, map->addr, map->addr,
map->size, 0);
ok = ok &&
!!VirtualProtectEx(procinfo.hProcess, map->addr, map->size,
__prot2nt(map->prot, false), &child_old_protect);
!!WriteProcessMemory(procinfo.hProcess, map->addr, map->addr,
(map->size + __pagesize - 1) & -__pagesize, 0);
if (map->prot != alloc_prot) {
uint32_t child_old_protect;
ok = ok &&
!!VirtualProtectEx(procinfo.hProcess, map->addr, map->size,
__prot2nt(map->prot, false), &child_old_protect);
}
if (!(map->prot & PROT_READ))
ok = ok && !!VirtualProtect(map->addr, map->size, parent_old_protect,
&parent_old_protect);