mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-23 04:48:31 +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

44
libc/proc/fork.c
View file

@ -20,6 +20,7 @@
#include "libc/calls/internal.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/struct/metasigaltstack.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/struct/timespec.h"
#include "libc/calls/syscall-nt.internal.h"
@ -43,6 +44,7 @@
#include "libc/runtime/syslib.internal.h"
#include "libc/stdio/internal.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/ss.h"
#include "libc/thread/itimer.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
@ -120,8 +122,7 @@ static void fork_prepare(void) {
if (_weaken(__dlopen_lock))
_weaken(__dlopen_lock)();
if (IsWindows())
if (_weaken(__proc_lock))
_weaken(__proc_lock)();
__proc_lock();
if (_weaken(cosmo_stack_lock))
_weaken(cosmo_stack_lock)();
__cxa_lock();
@ -155,8 +156,7 @@ static void fork_parent(void) {
if (_weaken(cosmo_stack_unlock))
_weaken(cosmo_stack_unlock)();
if (IsWindows())
if (_weaken(__proc_unlock))
_weaken(__proc_unlock)();
__proc_unlock();
if (_weaken(__dlopen_unlock))
_weaken(__dlopen_unlock)();
if (_weaken(__localtime_unlock))
@ -167,7 +167,7 @@ static void fork_parent(void) {
_pthread_mutex_unlock(&supreme_lock);
}
static void fork_child(void) {
static void fork_child(int ppid_win32, int ppid_cosmo) {
if (_weaken(__rand64_wipe))
_weaken(__rand64_wipe)();
_pthread_mutex_wipe_np(&__fds_lock_obj);
@ -194,6 +194,8 @@ static void fork_child(void) {
_pthread_mutex_wipe_np(&__sig_worker_lock);
if (_weaken(__sig_init))
_weaken(__sig_init)();
if (_weaken(sys_getppid_nt_wipe))
_weaken(sys_getppid_nt_wipe)(ppid_win32, ppid_cosmo);
}
if (_weaken(_pthread_onfork_child))
_weaken(_pthread_onfork_child)();
@ -202,8 +204,9 @@ static void fork_child(void) {
int _fork(uint32_t dwCreationFlags) {
struct Dll *e;
int ax, dx, tid, parent;
parent = __pid;
int ax, dx, tid, ppid_win32, ppid_cosmo;
ppid_win32 = IsWindows() ? GetCurrentProcessId() : 0;
ppid_cosmo = __pid;
BLOCK_SIGNALS;
fork_prepare();
if (!IsWindows()) {
@ -223,7 +226,7 @@ int _fork(uint32_t dwCreationFlags) {
// get new thread id
struct CosmoTib *tib = __get_tls();
struct PosixThread *pt = (struct PosixThread *)tib->tib_pthread;
struct PosixThread *me = (struct PosixThread *)tib->tib_pthread;
tid = IsLinux() || IsXnuSilicon() ? dx : sys_gettid();
atomic_init(&tib->tib_ctid, tid);
atomic_init(&tib->tib_ptid, tid);
@ -243,10 +246,10 @@ int _fork(uint32_t dwCreationFlags) {
// turn other threads into zombies
// we can't free() them since we're monopolizing all locks
// we assume the operating system already reclaimed system handles
dll_remove(&_pthread_list, &pt->list);
dll_remove(&_pthread_list, &me->list);
struct Dll *old_threads = _pthread_list;
_pthread_list = 0;
dll_make_first(&_pthread_list, &pt->list);
dll_make_first(&_pthread_list, &me->list);
atomic_init(&_pthread_count, 1);
// get new system thread handle
@ -264,25 +267,38 @@ int _fork(uint32_t dwCreationFlags) {
atomic_init(&tib->tib_sigpending, 0);
// we can't be canceled if the canceler no longer exists
atomic_init(&pt->pt_canceled, false);
atomic_init(&me->pt_canceled, false);
// forget locks
bzero(tib->tib_locks, sizeof(tib->tib_locks));
// xnu fork() doesn't preserve sigaltstack()
if (IsXnu() && me->tib->tib_sigstack_addr) {
struct sigaltstack_bsd ss;
ss.ss_sp = me->tib->tib_sigstack_addr;
ss.ss_size = me->tib->tib_sigstack_size;
ss.ss_flags = me->tib->tib_sigstack_flags;
if (IsXnuSilicon()) {
__syslib->__sigaltstack(&ss, 0);
} else {
sys_sigaltstack(&ss, 0);
}
}
// run user fork callbacks
fork_child();
fork_child(ppid_win32, ppid_cosmo);
// free threads
if (_weaken(_pthread_free)) {
while ((e = dll_first(old_threads))) {
pt = POSIXTHREAD_CONTAINER(e);
struct PosixThread *pt = POSIXTHREAD_CONTAINER(e);
atomic_init(&pt->tib->tib_syshand, 0);
dll_remove(&old_threads, e);
_weaken(_pthread_free)(pt);
}
}
STRACE("fork() → 0 (child of %d)", parent);
STRACE("fork() → 0 (child of %d)", ppid_cosmo);
} else {
// this is the parent process
fork_parent();