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

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

ape/ape.lds

@@ -596,7 +596,7 @@ ape_stack_offset = 0;
 ape_stack_vaddr = DEFINED(ape_stack_vaddr) ? ape_stack_vaddr : 0x700000000000;
 ape_stack_paddr = ape_ram_paddr + ape_ram_filesz;
 ape_stack_filesz = 0;
-ape_stack_memsz = DEFINED(ape_stack_memsz) ? ape_stack_memsz : 8 * 1024 * 1024;
+ape_stack_memsz = DEFINED(ape_stack_memsz) ? ape_stack_memsz : 4 * 1024 * 1024;
 
 ape_note_offset = ape_cod_offset + (ape_note - ape_cod_vaddr);
 ape_note_filesz = ape_note_end - ape_note;

libc/calls/metalfile.c

@@ -67,10 +67,9 @@ textstartup void InitializeMetalFile(void) {
     size_t size = ROUNDUP(_ezip - __executable_start, 4096);
     // TODO(jart): Restore support for ZIPOS on metal.
     void *copied_base;
-    struct DirectMap dm;
+    void *addr = sys_mmap_metal(NULL, size, PROT_READ | PROT_WRITE,
-    dm = sys_mmap_metal(NULL, size, PROT_READ | PROT_WRITE,
                                 MAP_SHARED_linux | MAP_ANONYMOUS_linux, -1, 0);
-    copied_base = dm.addr;
+    copied_base = addr;
     npassert(copied_base != (void *)-1);
     memcpy(copied_base, (void *)(BANE + IMAGE_BASE_PHYSICAL), size);
     __ape_com_base = copied_base;

libc/calls/openat-metal.c

@@ -49,11 +49,9 @@ int sys_openat_metal(int dirfd, const char *file, int flags, unsigned mode) {
   if ((fd = __reservefd(-1)) == -1)
     return -1;
   if (!_weaken(calloc) || !_weaken(free)) {
-    struct DirectMap dm;
+    state = sys_mmap_metal(NULL, ROUNDUP(sizeof(struct MetalFile), 4096),
-    dm = sys_mmap_metal(NULL, ROUNDUP(sizeof(struct MetalFile), 4096),
+                           PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS,
-                        PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1,
+                           -1, 0);
-                        0);
-    state = dm.addr;
     if (state == (void *)-1)
       return -1;
   } else {

libc/calls/syscall-nt.internal.h

@@ -2,6 +2,9 @@
 #define COSMOPOLITAN_LIBC_CALLS_SYSCALL_NT_INTERNAL_H_
 COSMOPOLITAN_C_START_
 
+extern int sys_getppid_nt_cosmo;
+extern int sys_getppid_nt_win32;
+
 bool32 sys_isatty(int);
 int sys_chdir_nt(const char *);
 int sys_dup_nt(int, int, int, int);
@@ -37,6 +40,7 @@ int sys_unlinkat_nt(int, const char *, int);
 int64_t sys_lseek_nt(int, int64_t, int);
 ssize_t sys_read_nt_impl(int, void *, size_t, int64_t);
 ssize_t sys_readlinkat_nt(int, const char *, char *, size_t);
+void sys_getppid_nt_wipe(int, int);
 
 COSMOPOLITAN_C_END_
 #endif /* COSMOPOLITAN_LIBC_CALLS_SYSCALL_NT_INTERNAL_H_ */

libc/intrin/clock_gettime-nt.c

@@ -59,7 +59,7 @@ textwindows int sys_clock_gettime_nt(int clock, struct timespec *ts) {
       //                     —Quoth MSDN § Windows Time
       //
       QueryUnbiasedInterruptTimePrecise(&hectons);
-      *ts = timespec_fromnanos(hectons * 100);
+      *ts = WindowsDurationToTimeSpec(hectons);
       return 0;
     case _CLOCK_MONOTONIC_COARSE:
       //
@@ -83,7 +83,7 @@ textwindows int sys_clock_gettime_nt(int clock, struct timespec *ts) {
       //                     —Quoth MSDN § QueryUnbiasedInterruptTimePrecise
       //
       QueryUnbiasedInterruptTime(&hectons);
-      *ts = timespec_fromnanos(hectons * 100);
+      *ts = WindowsDurationToTimeSpec(hectons);
       return 0;
     case _CLOCK_BOOTTIME:
       //
@@ -95,7 +95,7 @@ textwindows int sys_clock_gettime_nt(int clock, struct timespec *ts) {
       //                     —Quoth MSDN § Interrupt Time
       //
       QueryInterruptTimePrecise(&hectons);
-      *ts = timespec_fromnanos(hectons * 100);
+      *ts = WindowsDurationToTimeSpec(hectons);
       return 0;
     case _CLOCK_PROCESS_CPUTIME_ID:
       GetProcessTimes(GetCurrentProcess(), &ftCreation, &ftExit, &ftKernel,

libc/intrin/describeallocationtype.c

@@ -0,0 +1,32 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/intrin/describeflags.h"
+#include "libc/macros.h"
+#include "libc/nt/enum/memflags.h"
+
+static const struct DescribeFlags kNtAllocationTypeFlags[] = {
+    {kNtMemCommit, "Commit"},    //
+    {kNtMemReserve, "Reserve"},  //
+    {kNtMemReset, "Reset"},      //
+};
+
+const char *_DescribeNtAllocationType(char buf[48], uint32_t x) {
+  return _DescribeFlags(buf, 48, kNtAllocationTypeFlags,
+                        ARRAYLEN(kNtAllocationTypeFlags), "kNtMem", x);
+}

libc/intrin/describeflags.h

@@ -29,6 +29,7 @@ const char *_DescribeMapping(char[8], int, int) libcesque;
 const char *_DescribeMremapFlags(char[30], int) libcesque;
 const char *_DescribeMsg(char[16], int) libcesque;
 const char *_DescribeMsyncFlags(char[48], int) libcesque;
+const char *_DescribeNtAllocationType(char[48], uint32_t);
 const char *_DescribeNtConsoleInFlags(char[256], uint32_t) libcesque;
 const char *_DescribeNtConsoleOutFlags(char[128], uint32_t) libcesque;
 const char *_DescribeNtCreationDisposition(uint32_t) libcesque;
@@ -87,6 +88,7 @@ const char *_DescribeWhichPrio(char[12], int) libcesque;
 #define DescribeMremapFlags(x)       _DescribeMremapFlags(alloca(30), x)
 #define DescribeMsg(x)               _DescribeMsg(alloca(16), x)
 #define DescribeMsyncFlags(x)        _DescribeMsyncFlags(alloca(48), x)
+#define DescribeNtAllocationType(x)  _DescribeNtAllocationType(alloca(48), x)
 #define DescribeNtConsoleInFlags(x)  _DescribeNtConsoleInFlags(alloca(256), x)
 #define DescribeNtConsoleOutFlags(x) _DescribeNtConsoleOutFlags(alloca(128), x)
 #define DescribeNtFileAccessFlags(x) _DescribeNtFileAccessFlags(alloca(512), x)

libc/intrin/directmap-metal.c

@@ -19,7 +19,6 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/metalfile.internal.h"
-#include "libc/intrin/directmap.h"
 #include "libc/macros.h"
 #include "libc/runtime/pc.internal.h"
 #include "libc/str/str.h"
@@ -32,19 +31,11 @@
 
 static uint64_t sys_mmap_metal_break;
 
-static struct DirectMap bad_mmap(void) {
+void *sys_mmap_metal(void *vaddr, size_t size, int prot, int flags, int fd,
-  struct DirectMap res;
+                     int64_t off) {
-  res.addr = (void *)-1;
-  res.maphandle = -1;
-  return res;
-}
-
-struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot, int flags,
-                                int fd, int64_t off) {
   /* asan runtime depends on this function */
   size_t i;
   struct mman *mm;
-  struct DirectMap res;
   uint64_t addr, faddr = 0, page, e, *pte, *fdpte, *pml4t;
   mm = __get_mm();
   pml4t = __get_pml4t();
@@ -54,18 +45,18 @@ struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot, int flags,
     struct Fd *sfd;
     struct MetalFile *file;
     if (off < 0 || fd < 0 || fd >= g_fds.n)
-      return bad_mmap();
+      return MAP_FAILED;
     sfd = &g_fds.p[fd];
     if (sfd->kind != kFdFile)
-      return bad_mmap();
+      return MAP_FAILED;
     file = (struct MetalFile *)sfd->handle;
     /* TODO: allow mapping partial page at end of file, if file size not
      * multiple of page size */
     if (off > file->size || size > file->size - off)
-      return bad_mmap();
+      return MAP_FAILED;
     faddr = (uint64_t)file->base + off;
     if (faddr % 4096 != 0)
-      return bad_mmap();
+      return MAP_FAILED;
   }
   if (!(flags & MAP_FIXED_linux)) {
     if (!addr) {
@@ -88,7 +79,7 @@ struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot, int flags,
       if ((flags & MAP_ANONYMOUS_linux)) {
         page = __new_page(mm);
         if (!page)
-          return bad_mmap();
+          return MAP_FAILED;
         __clear_page(BANE + page);
         e = page | PAGE_RSRV | PAGE_U;
         if ((prot & PROT_WRITE))
@@ -114,9 +105,7 @@ struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot, int flags,
       break;
     }
   }
-  res.addr = (void *)addr;
+  return (void *)addr;
-  res.maphandle = -1;
-  return res;
 }
 
 #endif /* __x86_64__ */

libc/intrin/directmap-nt.c

@@ -1,122 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/assert.h"
-#include "libc/calls/internal.h"
-#include "libc/calls/state.internal.h"
-#include "libc/errno.h"
-#include "libc/intrin/directmap.h"
-#include "libc/nt/enum/filemapflags.h"
-#include "libc/nt/enum/pageflags.h"
-#include "libc/nt/errors.h"
-#include "libc/nt/memory.h"
-#include "libc/nt/runtime.h"
-#include "libc/nt/struct/processmemorycounters.h"
-#include "libc/nt/struct/securityattributes.h"
-#include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/o.h"
-#include "libc/sysv/consts/prot.h"
-
-textwindows struct DirectMap sys_mmap_nt(void *addr, size_t size, int prot,
-                                         int flags, int fd, int64_t off) {
-
-  int64_t handle;
-  if (flags & MAP_ANONYMOUS) {
-    handle = kNtInvalidHandleValue;
-  } else {
-    handle = g_fds.p[fd].handle;
-  }
-
-  // mark map handle as inheritable if fork might need it
-  const struct NtSecurityAttributes *mapsec;
-  if ((flags & MAP_TYPE) == MAP_SHARED) {
-    mapsec = &kNtIsInheritable;
-  } else {
-    mapsec = 0;
-  }
-
-  // nt will whine under many circumstances if we change the execute bit
-  // later using mprotect(). the workaround is to always request execute
-  // and then virtualprotect() it away until we actually need it. please
-  // note that open-nt.c always requests an kNtGenericExecute accessmask
-  int iscow = false;
-  struct ProtectNt fl;
-  if (handle != -1) {
-    if ((flags & MAP_TYPE) != MAP_SHARED) {
-      // windows has cow pages but they can't propagate across fork()
-      // that means we only get copy-on-write for the root process :(
-      fl = (struct ProtectNt){kNtPageExecuteWritecopy,
-                              kNtFileMapCopy | kNtFileMapExecute};
-      iscow = true;
-    } else {
-      if ((g_fds.p[fd].flags & O_ACCMODE) == O_RDONLY) {
-        fl = (struct ProtectNt){kNtPageExecuteRead,
-                                kNtFileMapRead | kNtFileMapExecute};
-      } else {
-        fl = (struct ProtectNt){kNtPageExecuteReadwrite,
-                                kNtFileMapWrite | kNtFileMapExecute};
-      }
-    }
-  } else {
-    unassert(flags & MAP_ANONYMOUS);
-    fl = (struct ProtectNt){kNtPageExecuteReadwrite,
-                            kNtFileMapWrite | kNtFileMapExecute};
-  }
-
-  int e = errno;
-  struct DirectMap dm;
-TryAgain:
-  if ((dm.maphandle = CreateFileMapping(handle, mapsec, fl.flags1,
-                                        (size + off) >> 32, (size + off), 0))) {
-    if ((dm.addr = MapViewOfFileEx(dm.maphandle, fl.flags2, off >> 32, off,
-                                   size, addr))) {
-      uint32_t oldprot;
-      if (VirtualProtect(dm.addr, size, __prot2nt(prot, iscow), &oldprot))
-        return dm;
-      UnmapViewOfFile(dm.addr);
-    }
-    CloseHandle(dm.maphandle);
-  } else if (!(prot & PROT_EXEC) &&              //
-             (fl.flags2 & kNtFileMapExecute) &&  //
-             GetLastError() == kNtErrorAccessDenied) {
-    // your file needs to have been O_CREAT'd with exec `mode` bits in
-    // order to be mapped with executable permission. we always try to
-    // get execute permission if the kernel will give it to us because
-    // win32 would otherwise forbid mprotect() from elevating later on
-    fl.flags2 &= ~kNtFileMapExecute;
-    switch (fl.flags1) {
-      case kNtPageExecuteWritecopy:
-        fl.flags1 = kNtPageWritecopy;
-        break;
-      case kNtPageExecuteReadwrite:
-        fl.flags1 = kNtPageReadwrite;
-        break;
-      case kNtPageExecuteRead:
-        fl.flags1 = kNtPageReadonly;
-        break;
-      default:
-        __builtin_unreachable();
-    }
-    errno = e;
-    goto TryAgain;
-  }
-
-  dm.maphandle = kNtInvalidHandleValue;
-  dm.addr = (void *)(intptr_t)-1;
-  return dm;
-}

libc/intrin/directmap.c

@@ -1,67 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/directmap.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/syscall-sysv.internal.h"
-#include "libc/dce.h"
-#include "libc/errno.h"
-#include "libc/intrin/describebacktrace.h"
-#include "libc/intrin/describeflags.h"
-#include "libc/intrin/strace.h"
-#include "libc/nt/runtime.h"
-#include "libc/runtime/memtrack.internal.h"
-#include "libc/runtime/runtime.h"
-#include "libc/runtime/syslib.internal.h"
-#include "libc/sysv/errfuns.h"
-
-/**
- * Obtains memory mapping directly from system.
- *
- * The mmap() function needs to track memory mappings in order to
- * support Windows NT and Address Sanitizer. That memory tracking can be
- * bypassed by calling this function. However the caller is responsible
- * for passing the magic memory handle on Windows NT to CloseHandle().
- *
- * @asyncsignalsafe
- */
-struct DirectMap sys_mmap(void *addr, size_t size, int prot, int flags, int fd,
-                          int64_t off) {
-  struct DirectMap d;
-  if ((__virtualsize += size) >= __virtualmax) {
-    d.maphandle = kNtInvalidHandleValue;
-    d.addr = (void *)enomem();
-  } else if (IsXnuSilicon()) {
-    long p = _sysret(__syslib->__mmap(addr, size, prot, flags, fd, off));
-    d.maphandle = kNtInvalidHandleValue;
-    d.addr = (void *)p;
-  } else if (!IsWindows() && !IsMetal()) {
-    d.addr = __sys_mmap(addr, size, prot, flags, fd, off, off);
-    d.maphandle = kNtInvalidHandleValue;
-  } else if (IsMetal()) {
-    d = sys_mmap_metal(addr, size, prot, flags, fd, off);
-  } else {
-    d = sys_mmap_nt(addr, size, prot, flags, fd, off);
-  }
-  if (d.addr == MAP_FAILED)
-    __virtualsize -= size;
-  KERNTRACE("sys_mmap(%.12p, %'zu, %s, %s, %d, %'ld) → {%.12p, %p}% m", addr,
-            size, DescribeProtFlags(prot), DescribeMapFlags(flags), fd, off,
-            d.addr, d.maphandle);
-  return d;
-}

libc/intrin/directmap.h

@@ -2,19 +2,7 @@
 #define COSMOPOLITAN_LIBC_INTRIN_DIRECTMAP_H_
 COSMOPOLITAN_C_START_
 
-struct ProtectNt {
+void *sys_mmap_metal(void *, size_t, int, int, int, int64_t) libcesque;
-  uint32_t flags1;
-  uint32_t flags2;
-};
-
-struct DirectMap {
-  void *addr;
-  int64_t maphandle;
-};
-
-struct DirectMap sys_mmap(void *, size_t, int, int, int, int64_t);
-struct DirectMap sys_mmap_nt(void *, size_t, int, int, int, int64_t);
-struct DirectMap sys_mmap_metal(void *, size_t, int, int, int, int64_t);
 int sys_munmap_metal(void *, size_t) libcesque;
 int __prot2nt(int, int) libcesque;
 

libc/intrin/mmap.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/state.internal.h"
 #include "libc/calls/syscall-sysv.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/dce.h"
@@ -33,10 +34,14 @@
 #include "libc/intrin/weaken.h"
 #include "libc/limits.h"
 #include "libc/macros.h"
+#include "libc/nt/enum/filemapflags.h"
 #include "libc/nt/enum/memflags.h"
+#include "libc/nt/enum/pageflags.h"
+#include "libc/nt/errors.h"
 #include "libc/nt/memory.h"
 #include "libc/nt/runtime.h"
 #include "libc/runtime/runtime.h"
+#include "libc/runtime/syslib.internal.h"
 #include "libc/runtime/zipos.internal.h"
 #include "libc/stdckdint.h"
 #include "libc/stdio/sysparam.h"
@@ -80,6 +85,11 @@
   } while (0)
 #endif
 
+struct DirectMap {
+  void *addr;
+  int64_t hand;
+};
+
 int __maps_compare(const struct Tree *ra, const struct Tree *rb) {
   const struct Map *a = (const struct Map *)MAP_TREE_CONTAINER(ra);
   const struct Map *b = (const struct Map *)MAP_TREE_CONTAINER(rb);
@@ -421,7 +431,7 @@ void __maps_insert(struct Map *map) {
   __maps_check();
 }
 
-// adds interval to rbtree (no sys_mmap)
+// adds interval to rbtree
 bool __maps_track(char *addr, size_t size, int prot, int flags) {
   struct Map *map;
   if (!(map = __maps_alloc()))
@@ -447,6 +457,125 @@ int __maps_untrack(char *addr, size_t size) {
   return rc;
 }
 
+textwindows dontinline static struct DirectMap sys_mmap_nt(
+    void *addr, size_t size, int prot, int flags, int fd, int64_t off) {
+  struct DirectMap dm;
+
+  // it's 5x faster
+  if (IsWindows() && (flags & MAP_ANONYMOUS) &&
+      (flags & MAP_TYPE) != MAP_SHARED) {
+    if (!(dm.addr = VirtualAlloc(addr, size, kNtMemReserve | kNtMemCommit,
+                                 __prot2nt(prot, false)))) {
+      dm.addr = MAP_FAILED;
+    }
+    dm.hand = MAPS_VIRTUAL;
+    return dm;
+  }
+
+  int64_t file_handle;
+  if (flags & MAP_ANONYMOUS) {
+    file_handle = kNtInvalidHandleValue;
+  } else {
+    file_handle = g_fds.p[fd].handle;
+  }
+
+  // mark map handle as inheritable if fork might need it
+  const struct NtSecurityAttributes *mapsec;
+  if ((flags & MAP_TYPE) == MAP_SHARED) {
+    mapsec = &kNtIsInheritable;
+  } else {
+    mapsec = 0;
+  }
+
+  // nt will whine under many circumstances if we change the execute bit
+  // later using mprotect(). the workaround is to always request execute
+  // and then virtualprotect() it away until we actually need it. please
+  // note that open-nt.c always requests an kNtGenericExecute accessmask
+  int iscow = 0;
+  int page_flags;
+  int file_flags;
+  if (file_handle != -1) {
+    if ((flags & MAP_TYPE) != MAP_SHARED) {
+      // windows has cow pages but they can't propagate across fork()
+      // that means we only get copy-on-write for the root process :(
+      page_flags = kNtPageExecuteWritecopy;
+      file_flags = kNtFileMapCopy | kNtFileMapExecute;
+      iscow = 1;
+    } else {
+      if ((g_fds.p[fd].flags & O_ACCMODE) == O_RDONLY) {
+        page_flags = kNtPageExecuteRead;
+        file_flags = kNtFileMapRead | kNtFileMapExecute;
+      } else {
+        page_flags = kNtPageExecuteReadwrite;
+        file_flags = kNtFileMapWrite | kNtFileMapExecute;
+      }
+    }
+  } else {
+    page_flags = kNtPageExecuteReadwrite;
+    file_flags = kNtFileMapWrite | kNtFileMapExecute;
+  }
+
+  int e = errno;
+TryAgain:
+  if ((dm.hand = CreateFileMapping(file_handle, mapsec, page_flags,
+                                   (size + off) >> 32, (size + off), 0))) {
+    if ((dm.addr = MapViewOfFileEx(dm.hand, file_flags, off >> 32, off, size,
+                                   addr))) {
+      uint32_t oldprot;
+      if (VirtualProtect(dm.addr, size, __prot2nt(prot, iscow), &oldprot))
+        return dm;
+      UnmapViewOfFile(dm.addr);
+    }
+    CloseHandle(dm.hand);
+  } else if (!(prot & PROT_EXEC) &&               //
+             (file_flags & kNtFileMapExecute) &&  //
+             GetLastError() == kNtErrorAccessDenied) {
+    // your file needs to have been O_CREAT'd with exec `mode` bits in
+    // order to be mapped with executable permission. we always try to
+    // get execute permission if the kernel will give it to us because
+    // win32 would otherwise forbid mprotect() from elevating later on
+    file_flags &= ~kNtFileMapExecute;
+    switch (page_flags) {
+      case kNtPageExecuteWritecopy:
+        page_flags = kNtPageWritecopy;
+        break;
+      case kNtPageExecuteReadwrite:
+        page_flags = kNtPageReadwrite;
+        break;
+      case kNtPageExecuteRead:
+        page_flags = kNtPageReadonly;
+        break;
+      default:
+        __builtin_unreachable();
+    }
+    errno = e;
+    goto TryAgain;
+  }
+
+  dm.hand = kNtInvalidHandleValue;
+  dm.addr = (void *)(intptr_t)-1;
+  return dm;
+}
+
+static struct DirectMap sys_mmap(void *addr, size_t size, int prot, int flags,
+                                 int fd, int64_t off) {
+  struct DirectMap d;
+  if (IsXnuSilicon()) {
+    long p = _sysret(__syslib->__mmap(addr, size, prot, flags, fd, off));
+    d.hand = kNtInvalidHandleValue;
+    d.addr = (void *)p;
+  } else if (IsWindows()) {
+    d = sys_mmap_nt(addr, size, prot, flags, fd, off);
+  } else if (IsMetal()) {
+    d.addr = sys_mmap_metal(addr, size, prot, flags, fd, off);
+    d.hand = kNtInvalidHandleValue;
+  } else {
+    d.addr = __sys_mmap(addr, size, prot, flags, fd, off, off);
+    d.hand = kNtInvalidHandleValue;
+  }
+  return d;
+}
+
 struct Map *__maps_alloc(void) {
   struct Map *map;
   uintptr_t tip = atomic_load_explicit(&__maps.freed, memory_order_relaxed);
@@ -467,7 +596,7 @@ struct Map *__maps_alloc(void) {
   if (sys.addr == MAP_FAILED)
     return 0;
   if (IsWindows())
-    CloseHandle(sys.maphandle);
+    CloseHandle(sys.hand);
   struct MapSlab *slab = sys.addr;
   while (!atomic_compare_exchange_weak(&__maps.slabs, &slab->next, slab)) {
   }
@@ -717,7 +846,7 @@ static void *__mmap_impl(char *addr, size_t size, int prot, int flags, int fd,
   map->off = off;
   map->prot = prot;
   map->flags = flags;
-  map->hand = res.maphandle;
+  map->hand = res.hand;
   if (IsWindows()) {
     map->iscow = (flags & MAP_TYPE) != MAP_SHARED && fd != -1;
     map->readonlyfile = (flags & MAP_TYPE) == MAP_SHARED && fd != -1 &&

libc/intrin/munmap-sysv.c

@@ -41,8 +41,6 @@ int sys_munmap(void *p, size_t n) {
   } else {
     rc = __sys_munmap(p, n);
   }
-  if (!rc)
-    __virtualsize -= n;
   KERNTRACE("sys_munmap(%p, %'zu) → %d", p, n, rc);
   return rc;
 }

libc/intrin/sig.c

@@ -83,7 +83,7 @@ struct SignalFrame {
 };
 
 __msabi extern typeof(GetStdHandle) *const __imp_GetStdHandle;
-__msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
+__msabi extern typeof(VirtualProtectEx) *const __imp_VirtualProtectEx;
 __msabi extern typeof(VirtualQuery) *const __imp_VirtualQuery;
 __msabi extern typeof(WriteFile) *const __imp_WriteFile;
 
@@ -566,7 +566,8 @@ textwindows wontreturn static void __sig_death(int sig, const char *thing) {
 //
 forceinline void __sig_reguard(void *page) {
   uint32_t old_protect;
-  __imp_VirtualProtect((void *)((uintptr_t)page & -__pagesize), __pagesize,
+  __imp_VirtualProtectEx(GetCurrentProcess(),
+                         (void *)((uintptr_t)page & -__pagesize), __pagesize,
                          kNtPageReadwrite | kNtPageGuard, &old_protect);
 }
 

libc/intrin/virtualalloc.c

@@ -1,7 +1,7 @@
 /*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
 │ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
 ╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
 │ Permission to use, copy, modify, and/or distribute this software for         │
 │ any purpose with or without fee is hereby granted, provided that the         │
@@ -16,22 +16,14 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/syscall-nt.internal.h"
+#include "libc/nt/memory.h"
-#include "libc/nt/enum/status.h"
-#include "libc/nt/nt/process.h"
-#include "libc/nt/process.h"
 #include "libc/nt/runtime.h"
-#include "libc/nt/struct/processbasicinformation.h"
 
-textwindows int sys_getppid_nt(void) {
+/**
-  struct NtProcessBasicInformation ProcessInformation;
+ * Allocates memory on The New Technology.
-  uint32_t gotsize = 0;
+ */
-  if (!NtError(
+textwindows void *VirtualAlloc(void *lpAddress, uint64_t dwSize,
-          NtQueryInformationProcess(GetCurrentProcess(), 0, &ProcessInformation,
+                               uint32_t flAllocationType, uint32_t flProtect) {
-                                    sizeof(ProcessInformation), &gotsize)) &&
+  return VirtualAllocEx(GetCurrentProcess(), lpAddress, dwSize,
-      gotsize >= sizeof(ProcessInformation) &&
+                        flAllocationType, flProtect);
-      ProcessInformation.InheritedFromUniqueProcessId) {
-    return ProcessInformation.InheritedFromUniqueProcessId;
-  }
-  return GetCurrentProcessId();
 }

libc/intrin/virtualallocex.c

@@ -19,32 +19,23 @@
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/intrin/describeflags.h"
 #include "libc/intrin/strace.h"
-#include "libc/macros.h"
-#include "libc/mem/alloca.h"
-#include "libc/nt/enum/memflags.h"
 #include "libc/nt/memory.h"
 #include "libc/nt/thunk/msabi.h"
 
 __msabi extern typeof(VirtualAllocEx) *const __imp_VirtualAllocEx;
 
-static const char *DescribeAllocationType(char buf[48], uint32_t x) {
+/**
-  const struct DescribeFlags kAllocationTypeFlags[] = {
+ * Allocates memory on The New Technology.
-      {kNtMemCommit, "Commit"},    //
+ */
-      {kNtMemReserve, "Reserve"},  //
+textwindows void *VirtualAllocEx(int64_t hProcess, void *lpAddress,
-      {kNtMemReset, "Reset"},      //
+                                 uint64_t dwSize, uint32_t flAllocationType,
-  };
+                                 uint32_t flProtect) {
-  return _DescribeFlags(buf, 48, kAllocationTypeFlags,
-                        ARRAYLEN(kAllocationTypeFlags), "kNtMem", x);
-}
-
-void *VirtualAllocEx(int64_t hProcess, void *lpAddress, uint64_t dwSize,
-                     uint32_t flAllocationType, uint32_t flProtect) {
   void *res = __imp_VirtualAllocEx(hProcess, lpAddress, dwSize,
                                    flAllocationType, flProtect);
   if (!res)
     __winerr();
   NTTRACE("VirtualAllocEx(%ld, %p, %'lu, %s, %s) → %p% m", hProcess, lpAddress,
-          dwSize, DescribeAllocationType(alloca(48), flAllocationType),
+          dwSize, DescribeNtAllocationType(flAllocationType),
           DescribeNtPageFlags(flProtect), res);
   return res;
 }

libc/intrin/virtualmax.c

@@ -19,4 +19,3 @@
 #include "libc/runtime/runtime.h"
 
 size_t __virtualmax = -1;
-size_t __virtualsize = 0;

libc/irq/acpi-xsdt.c

@@ -58,9 +58,8 @@ textstartup void *_AcpiOsMapUncachedMemory(uintptr_t phy, size_t n) {
 }
 
 textstartup static void *_AcpiOsAllocatePages(size_t n) {
-  struct DirectMap dm = sys_mmap_metal(NULL, n, PROT_READ | PROT_WRITE,
+  void *addr = sys_mmap_metal(NULL, n, PROT_READ | PROT_WRITE,
                               MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-  void *addr = dm.addr;
   if (addr == (void *)-1)
     addr = NULL;
   return addr;

libc/nt/kernel32/VirtualAlloc.S

@@ -1,18 +0,0 @@
-#include "libc/nt/codegen.h"
-.imp	kernel32,__imp_VirtualAlloc,VirtualAlloc
-
-	.text.windows
-	.ftrace1
-VirtualAlloc:
-	.ftrace2
-#ifdef __x86_64__
-	push	%rbp
-	mov	%rsp,%rbp
-	mov	__imp_VirtualAlloc(%rip),%rax
-	jmp	__sysv2nt
-#elif defined(__aarch64__)
-	mov	x0,#0
-	ret
-#endif
-	.endfn	VirtualAlloc,globl
-	.previous

libc/nt/master.sh

@@ -9,7 +9,6 @@
 # KERNEL32.DLL
 #
 #	Name							Actual							DLL		Arity
-
 imp	''							CreateDirectoryW					kernel32	2
 imp	''							CreateFileA						kernel32	7
 imp	''							CreateFileMappingNumaW					kernel32	7
@@ -303,7 +302,6 @@ imp	'UnlockFile'						UnlockFile						kernel32	5
 imp	'UnmapViewOfFile2'					UnmapViewOfFile2					kernel32	2
 imp	'UnmapViewOfFileEx'					UnmapViewOfFileEx					kernel32	3
 imp	'UpdateProcThreadAttribute'				UpdateProcThreadAttribute				kernel32	7
-imp	'VirtualAlloc'						VirtualAlloc						kernel32	4
 imp	'VirtualFree'						VirtualFree						kernel32	3
 imp	'VirtualLock'						VirtualLock						kernel32	2
 imp	'VirtualQuery'						VirtualQuery						kernel32	3

libc/proc/BUILD.mk

@@ -30,6 +30,7 @@ LIBC_PROC_A_DIRECTDEPS =				\
 	LIBC_MEM					\
 	LIBC_NEXGEN32E					\
 	LIBC_NT_KERNEL32				\
+	LIBC_NT_NTDLL					\
 	LIBC_NT_PSAPI					\
 	LIBC_RUNTIME					\
 	LIBC_STR					\

libc/proc/execve-nt.greg.c

@@ -24,16 +24,23 @@
 #include "libc/calls/syscall-nt.internal.h"
 #include "libc/errno.h"
 #include "libc/fmt/itoa.h"
+#include "libc/intrin/dll.h"
 #include "libc/intrin/fds.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/intrin/strace.h"
 #include "libc/mem/mem.h"
+#include "libc/nt/accounting.h"
 #include "libc/nt/enum/processaccess.h"
 #include "libc/nt/enum/startf.h"
+#include "libc/nt/enum/status.h"
 #include "libc/nt/errors.h"
 #include "libc/nt/files.h"
 #include "libc/nt/process.h"
 #include "libc/nt/runtime.h"
 #include "libc/nt/struct/processinformation.h"
 #include "libc/nt/struct/startupinfo.h"
+#include "libc/nt/synchronization.h"
+#include "libc/nt/thread.h"
 #include "libc/nt/thunk/msabi.h"
 #include "libc/proc/describefds.internal.h"
 #include "libc/proc/ntspawn.h"
@@ -41,6 +48,7 @@
 #include "libc/str/str.h"
 #include "libc/sysv/consts/at.h"
 #include "libc/sysv/consts/o.h"
+#include "libc/sysv/consts/sig.h"
 #include "libc/sysv/errfuns.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
@@ -65,13 +73,11 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
   _pthread_lock();                          // order matters
 
   // new process should be a child of our parent
-  int64_t hParentProcess;
+  int64_t hParentProcess =
-  int ppid = sys_getppid_nt();
+      sys_getppid_nt_win32
-  if (!(hParentProcess = OpenProcess(
+          ? OpenProcess(kNtProcessDupHandle | kNtProcessCreateProcess, false,
-            kNtProcessDupHandle | kNtProcessCreateProcess, false, ppid))) {
+                        sys_getppid_nt_win32)
-    sys_execve_nt_abort(sigmask);
+          : 0;
-    return -1;
-  }
 
   // inherit pid
   char pidvar[11 + 21];
@@ -81,6 +87,16 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
   char maskvar[6 + 21];
   FormatUint64(stpcpy(maskvar, "_MASK="), sigmask);
 
+  // inherit parent process id
+  char ppidvar[12 + 21 + 1 + 21 + 1], *p = ppidvar;
+  p = stpcpy(p, "_COSMO_PPID=");
+  if (hParentProcess) {
+    p = FormatUint64(p, sys_getppid_nt_win32);
+    *p++ = ':';
+    p = FormatUint64(p, __pid);
+    setenv("_COSMO_PPID", ppidvar, true);
+  }
+
   // define stdio handles for the spawned subprocess
   struct NtStartupInfo si = {
       .cb = sizeof(struct NtStartupInfo),
@@ -94,12 +110,21 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
     }
   }
 
+  // which process is responsible for spawning the child?
+  int64_t hCreatorProcess;
+  if (hParentProcess) {
+    hCreatorProcess = hParentProcess;
+  } else {
+    hCreatorProcess = GetCurrentProcess();
+  }
+
   // pass serialized file descriptor table in environment
   char *fdspec;
   int64_t *lpExplicitHandles;
   uint32_t dwExplicitHandleCount;
-  if (!(fdspec = __describe_fds(g_fds.p, g_fds.n, &si, hParentProcess,
+  if (!(fdspec = __describe_fds(g_fds.p, g_fds.n, &si, hCreatorProcess,
                                 &lpExplicitHandles, &dwExplicitHandleCount))) {
+    if (hParentProcess)
       CloseHandle(hParentProcess);
     sys_execve_nt_abort(sigmask);
     return -1;
@@ -114,11 +139,13 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
   // launch the process
   struct NtProcessInformation pi;
   int rc = ntspawn(&(struct NtSpawnArgs){
-      AT_FDCWD, program, argv, envp, (char *[]){fdspec, maskvar, pidvar, 0}, 0,
+      AT_FDCWD, program, argv, envp,
-      0, hParentProcess, lpExplicitHandles, dwExplicitHandleCount, &si, &pi});
+      (char *[]){fdspec, maskvar, pidvar, ppidvar, 0}, 0, 0, hCreatorProcess,
-  __undescribe_fds(hParentProcess, lpExplicitHandles, dwExplicitHandleCount);
+      lpExplicitHandles, dwExplicitHandleCount, &si, &pi});
+  __undescribe_fds(hCreatorProcess, lpExplicitHandles, dwExplicitHandleCount);
   if (rc == -1) {
     free(fdspec);
+    if (hParentProcess)
       CloseHandle(hParentProcess);
     sys_execve_nt_abort(sigmask);
     if (GetLastError() == kNtErrorSharingViolation) {
@@ -128,10 +155,12 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
     }
   }
 
+  // check if parent spoofing worked
+  if (hParentProcess) {
     // give child to libc/proc/proc.c worker thread in parent
     int64_t handle;
-  if (DuplicateHandle(GetCurrentProcess(), pi.hProcess, hParentProcess, &handle,
+    if (DuplicateHandle(GetCurrentProcess(), pi.hProcess, hParentProcess,
-                      0, false, kNtDuplicateSameAccess)) {
+                        &handle, 0, false, kNtDuplicateSameAccess)) {
       unassert(!(handle & 0xFFFFFFFFFF000000));
       __imp_TerminateProcess(-1, 0x23000000u | handle);
     } else {
@@ -142,4 +171,39 @@ textwindows int sys_execve_nt(const char *program, char *const argv[],
     __builtin_unreachable();
   }
 
+  // we couldn't reparent the new process
+  STRACE("warning: execve() lingering due to non-cosmo parent process");
+
+  // terminate other threads
+  struct Dll *e;
+  struct PosixThread *me = _pthread_self();
+  for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
+    struct PosixThread *pt = POSIXTHREAD_CONTAINER(e);
+    if (pt == me)
+      continue;
+    TerminateThread(
+        atomic_load_explicit(&pt->tib->tib_syshand, memory_order_relaxed),
+        SIGKILL);
+  }
+
+  // wait for child to terminate and propagate exit code
+  for (;;) {
+    uint32_t status;
+    WaitForSingleObject(pi.hProcess, -1u);
+    GetExitCodeProcess(pi.hProcess, &status);
+    if (status != kNtStillActive) {
+      if ((status & 0xFF000000u) == 0x23000000u) {
+        // handle child execve()
+        CloseHandle(pi.hProcess);
+        pi.hProcess = status & 0x00FFFFFF;
+      } else {
+        // handle child _Exit()
+        if (status == 0xc9af3d51u)
+          status = kNtStillActive;
+        TerminateThisProcess(status);
+      }
+    }
+  }
+}
+
 #endif /* __x86_64__ */

libc/proc/execve.c

@@ -57,11 +57,6 @@
  * compiled by MSVC or Cygwin is launched instead, then only the stdio
  * file descriptors can be passed along.
  *
- * On Windows, the parent process must be a cosmo program. If you're
- * calling execve() from a program that wasn't launched by cosmopolitan
- * bash, or some similar program, then ask yourself if what you really
- * want is to either (a) call fork() first, or (b) use posix_spawn().
- *
  * On Windows, `argv` and `envp` can't contain binary strings. They need
  * to be valid UTF-8 in order to round-trip the WIN32 API, without being
  * corrupted.

libc/proc/fork-nt.c

@@ -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) {
+        // 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,
+                                    kNtMemReserve | kNtMemCommit, page_flags);
-                                    kNtPageExecuteReadwrite);
       }
     }
+    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,
+    ok = ok &&
-                                    map->size, 0);
+         !!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);

libc/proc/fork.c

@@ -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))
+    __proc_lock();
-      _weaken(__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))
+    __proc_unlock();
-      _weaken(__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;
+  int ax, dx, tid, ppid_win32, ppid_cosmo;
-  parent = __pid;
+  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();

libc/proc/getppid-nt.c

@@ -0,0 +1,93 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/atomic.h"
+#include "libc/calls/syscall-nt.internal.h"
+#include "libc/cosmo.h"
+#include "libc/dce.h"
+#include "libc/fmt/itoa.h"
+#include "libc/nt/enum/status.h"
+#include "libc/nt/nt/process.h"
+#include "libc/nt/process.h"
+#include "libc/nt/runtime.h"
+#include "libc/nt/struct/processbasicinformation.h"
+#include "libc/runtime/internal.h"
+#include "libc/runtime/runtime.h"
+
+int sys_getppid_nt_win32;
+int sys_getppid_nt_cosmo;
+
+textwindows static int sys_getppid_nt_ntdll(void) {
+  struct NtProcessBasicInformation ProcessInformation;
+  uint32_t gotsize = 0;
+  if (!NtError(
+          NtQueryInformationProcess(GetCurrentProcess(), 0, &ProcessInformation,
+                                    sizeof(ProcessInformation), &gotsize)) &&
+      gotsize >= sizeof(ProcessInformation) &&
+      ProcessInformation.InheritedFromUniqueProcessId) {
+    return ProcessInformation.InheritedFromUniqueProcessId;
+  }
+  return 0;
+}
+
+static void sys_getppid_nt_extract(const char *str) {
+  int c;
+  int win32 = 0;
+  int cosmo = 0;
+  if (str) {
+    for (;;) {
+      c = *str;
+      if (!('0' <= c && c <= '9'))
+        break;
+      win32 *= 10;
+      win32 += c - '0';
+      ++str;
+    }
+    if (win32 && *str++ == ':') {
+      for (;;) {
+        c = *str;
+        if (!('0' <= c && c <= '9'))
+          break;
+        cosmo *= 10;
+        cosmo += c - '0';
+        ++str;
+      }
+      if (win32 == sys_getppid_nt_ntdll()) {
+        sys_getppid_nt_win32 = win32;
+        sys_getppid_nt_cosmo = cosmo;
+      }
+    }
+  }
+}
+
+__attribute__((__constructor__(90))) static void init(void) {
+  if (!IsWindows())
+    return;
+  sys_getppid_nt_extract(getenv("_COSMO_PPID"));
+}
+
+textwindows int sys_getppid_nt(void) {
+  if (sys_getppid_nt_cosmo)
+    return sys_getppid_nt_cosmo;
+  return sys_getppid_nt_ntdll();
+}
+
+textwindows void sys_getppid_nt_wipe(int win32, int cosmo) {
+  sys_getppid_nt_win32 = win32;
+  sys_getppid_nt_cosmo = cosmo;
+}

libc/proc/posix_spawn.c

@@ -51,6 +51,7 @@
 #include "libc/nt/enum/processcreationflags.h"
 #include "libc/nt/enum/startf.h"
 #include "libc/nt/files.h"
+#include "libc/nt/process.h"
 #include "libc/nt/runtime.h"
 #include "libc/nt/struct/processinformation.h"
 #include "libc/nt/struct/startupinfo.h"
@@ -59,6 +60,7 @@
 #include "libc/proc/posix_spawn.h"
 #include "libc/proc/posix_spawn.internal.h"
 #include "libc/proc/proc.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/sock/sock.h"
 #include "libc/stdio/stdio.h"
@@ -396,6 +398,14 @@ static textwindows errno_t posix_spawn_nt_impl(
   }
   FormatUint64(stpcpy(maskvar, "_MASK="), childmask);
 
+  // inherit parent process id
+  char ppidvar[12 + 21 + 1 + 21 + 1], *p = ppidvar;
+  p = stpcpy(p, "_COSMO_PPID=");
+  p = FormatUint64(p, GetCurrentProcessId());
+  *p++ = ':';
+  p = FormatUint64(p, __pid);
+  setenv("_COSMO_PPID", ppidvar, true);
+
   // launch process
   int rc = -1;
   struct NtProcessInformation procinfo;

libc/runtime/morph.c

@@ -24,12 +24,13 @@
 #include "libc/intrin/kprintf.h"
 #include "libc/nt/enum/pageflags.h"
 #include "libc/nt/memory.h"
+#include "libc/nt/runtime.h"
 #include "libc/nt/thunk/msabi.h"
 #include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/nr.h"
 #include "libc/sysv/consts/prot.h"
 
-__msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
+__msabi extern typeof(VirtualProtectEx) *const __imp_VirtualProtectEx;
 
 __funline void __morph_mprotect(void *addr, size_t size, int prot, int ntprot) {
 #ifdef __x86_64__
@@ -54,7 +55,7 @@ __funline void __morph_mprotect(void *addr, size_t size, int prot, int ntprot) {
     }
 #endif
   } else {
-    __imp_VirtualProtect(addr, size, ntprot, &op);
+    __imp_VirtualProtectEx(GetCurrentProcess(), addr, size, ntprot, &op);
   }
 #elif defined(__aarch64__)
   register long r0 asm("x0") = (long)addr;

libc/runtime/runtime.h

@@ -83,7 +83,6 @@ extern uint64_t kStartTsc;
 extern const char kNtSystemDirectory[];
 extern const char kNtWindowsDirectory[];
 extern size_t __virtualmax;
-extern size_t __virtualsize;
 extern size_t __stackmax;
 extern bool32 __isworker;
 /* utilities */

libc/runtime/winmain.greg.c

@@ -79,7 +79,7 @@ __msabi extern typeof(SetConsoleMode) *const __imp_SetConsoleMode;
 __msabi extern typeof(SetConsoleOutputCP) *const __imp_SetConsoleOutputCP;
 __msabi extern typeof(SetEnvironmentVariable) *const __imp_SetEnvironmentVariableW;
 __msabi extern typeof(SetStdHandle) *const __imp_SetStdHandle;
-__msabi extern typeof(VirtualProtect) *const __imp_VirtualProtect;
+__msabi extern typeof(VirtualProtectEx) *const __imp_VirtualProtectEx;
 __msabi extern typeof(WriteFile) *const __imp_WriteFile;
 // clang-format on
 
@@ -206,10 +206,11 @@ abi wontreturn static void WinInit(const char16_t *cmdline) {
   int stackprot = (intptr_t)ape_stack_prot;
   if (~stackprot & PROT_EXEC) {
     uint32_t old;
-    __imp_VirtualProtect(stackaddr, stacksize, kNtPageReadwrite, &old);
+    __imp_VirtualProtectEx(GetCurrentProcess(), stackaddr, stacksize,
+                           kNtPageReadwrite, &old);
   }
   uint32_t oldattr;
-  __imp_VirtualProtect(stackaddr, GetGuardSize(),
+  __imp_VirtualProtectEx(GetCurrentProcess(), stackaddr, GetGuardSize(),
                          kNtPageReadwrite | kNtPageGuard, &oldattr);
   if (_weaken(__maps_stack)) {
     struct NtSystemInfo si;

libc/thread/isstackoverflow.c

@@ -23,17 +23,36 @@
 #include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/auxv.h"
 #include "libc/sysv/consts/sig.h"
+#include "libc/thread/thread.h"
 
 /**
- * Returns true if signal is most likely a stack overflow.
+ * Returns true if signal is caused by stack overflow.
  */
 char __is_stack_overflow(siginfo_t *si, void *arg) {
+
+  // sanity check
   ucontext_t *uc = arg;
   if (!si || !uc)
     return false;
-  if (si->si_signo != SIGSEGV && si->si_signo != SIGBUS)
+  if (si->si_signo != SIGSEGV &&  //
+      si->si_signo != SIGBUS)
     return false;
-  intptr_t sp = uc->uc_mcontext.SP;
+
-  intptr_t fp = (intptr_t)si->si_addr;
+  // get stack information
-  return ABS(fp - sp) < __pagesize;
+  pthread_attr_t attr;
+  if (pthread_getattr_np(pthread_self(), &attr))
+    return false;
+  size_t guardsize;
+  if (pthread_attr_getguardsize(&attr, &guardsize))
+    return false;
+  void *stackaddr;
+  size_t stacksize;
+  if (pthread_attr_getstack(&attr, &stackaddr, &stacksize))
+    return false;
+
+  // determine if faulting address is inside guard region
+  char *x = (char *)si->si_addr;
+  char *lo = (char *)stackaddr - guardsize;
+  char *hi = (char *)stackaddr;
+  return lo <= x && x < hi;
 }

libc/vga/tty.greg.c

@@ -167,7 +167,6 @@ void _StartTty(struct Tty *tty, unsigned char type, unsigned short yp,
                unsigned short startx, unsigned char yc, unsigned char xc,
                void *fb, unsigned init_flags) {
   unsigned short yn, xn, xs = xp * sizeof(TtyCanvasColor);
-  struct DirectMap dm;
   bzero(tty, sizeof(struct Tty));
   SetYp(tty, yp);
   SetXp(tty, xp);
@@ -183,9 +182,9 @@ void _StartTty(struct Tty *tty, unsigned char type, unsigned short yp,
       tty->canvas = fb;
       xs = xsfb;
     } else {
-      dm = sys_mmap_metal(NULL, (size_t)yp * xs, PROT_READ | PROT_WRITE,
+      void *addr = sys_mmap_metal(NULL, (size_t)yp * xs, PROT_READ | PROT_WRITE,
                                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-      if (dm.addr == (void *)-1) {
+      if (addr == (void *)-1) {
         /*
          * We are a bit low on memory.  Try to go on anyway, & initialize
          * our tty as an emergency console.
@@ -194,7 +193,7 @@ void _StartTty(struct Tty *tty, unsigned char type, unsigned short yp,
         tty->canvas = fb;
         xs = xsfb;
       } else
-        tty->canvas = dm.addr;
+        tty->canvas = addr;
     }
   }
   SetYn(tty, yn);

test/libc/calls/setrlimit_test.c

@@ -1,242 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "dsp/core/core.h"
-#include "libc/calls/calls.h"
-#include "libc/calls/struct/rlimit.h"
-#include "libc/calls/struct/timespec.h"
-#include "libc/dce.h"
-#include "libc/errno.h"
-#include "libc/intrin/directmap.h"
-#include "libc/intrin/safemacros.h"
-#include "libc/limits.h"
-#include "libc/runtime/runtime.h"
-#include "libc/stdio/rand.h"
-#include "libc/stdio/stdio.h"
-#include "libc/sysv/consts/auxv.h"
-#include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/o.h"
-#include "libc/sysv/consts/prot.h"
-#include "libc/sysv/consts/rlimit.h"
-#include "libc/sysv/consts/sig.h"
-#include "libc/testlib/testlib.h"
-#include "libc/time.h"
-#include "libc/x/xsigaction.h"
-#include "libc/x/xspawn.h"
-
-#define MEM (64 * 1024 * 1024)
-
-static char tmpname[PATH_MAX];
-
-void OnSigxcpu(int sig) {
-  ASSERT_EQ(SIGXCPU, sig);
-  _Exit(0);
-}
-
-void OnSigxfsz(int sig) {
-  unlink(tmpname);
-  ASSERT_EQ(SIGXFSZ, sig);
-  _Exit(0);
-}
-
-TEST(setrlimit, testCpuLimit) {
-  int wstatus;
-  struct rlimit rlim;
-  struct timespec start;
-  double matrices[3][3][3];
-  if (IsWindows())
-    return;  // of course it doesn't work on windows
-  if (IsXnu())
-    return;  // TODO(jart): it worked before
-  if (IsOpenbsd())
-    return;  // TODO(jart): fix flake
-  ASSERT_NE(-1, (wstatus = xspawn(0)));
-  if (wstatus == -2) {
-    ASSERT_EQ(0, xsigaction(SIGXCPU, OnSigxcpu, 0, 0, 0));
-    ASSERT_EQ(0, getrlimit(RLIMIT_CPU, &rlim));
-    rlim.rlim_cur = 1;  // set soft limit to one second
-    ASSERT_EQ(0, setrlimit(RLIMIT_CPU, &rlim));
-    start = timespec_real();
-    do {
-      matmul3(matrices[0], matrices[1], matrices[2]);
-      matmul3(matrices[0], matrices[1], matrices[2]);
-      matmul3(matrices[0], matrices[1], matrices[2]);
-      matmul3(matrices[0], matrices[1], matrices[2]);
-    } while (timespec_sub(timespec_real(), start).tv_sec < 5);
-    _Exit(1);
-  }
-  EXPECT_TRUE(WIFEXITED(wstatus));
-  EXPECT_FALSE(WIFSIGNALED(wstatus));
-  EXPECT_EQ(0, WEXITSTATUS(wstatus));
-  EXPECT_EQ(0, WTERMSIG(wstatus));
-}
-
-TEST(setrlimit, testFileSizeLimit) {
-  char junkdata[512];
-  int i, fd, wstatus;
-  struct rlimit rlim;
-  if (IsWindows())
-    return; /* of course it doesn't work on windows */
-  ASSERT_NE(-1, (wstatus = xspawn(0)));
-  if (wstatus == -2) {
-    ASSERT_EQ(0, xsigaction(SIGXFSZ, OnSigxfsz, 0, 0, 0));
-    ASSERT_EQ(0, getrlimit(RLIMIT_FSIZE, &rlim));
-    rlim.rlim_cur = 1024 * 1024; /* set soft limit to one megabyte */
-    ASSERT_EQ(0, setrlimit(RLIMIT_FSIZE, &rlim));
-    snprintf(tmpname, sizeof(tmpname), "%s/%s.%d",
-             firstnonnull(getenv("TMPDIR"), "/tmp"),
-             firstnonnull(program_invocation_short_name, "unknown"), getpid());
-    ASSERT_NE(-1, (fd = open(tmpname, O_RDWR | O_CREAT | O_TRUNC, 0644)));
-    rngset(junkdata, 512, lemur64, -1);
-    for (i = 0; i < 5 * 1024 * 1024 / 512; ++i) {
-      ASSERT_EQ(512, write(fd, junkdata, 512));
-    }
-    close(fd);
-    unlink(tmpname);
-    _Exit(1);
-  }
-  EXPECT_TRUE(WIFEXITED(wstatus));
-  EXPECT_FALSE(WIFSIGNALED(wstatus));
-  EXPECT_EQ(0, WEXITSTATUS(wstatus));
-  EXPECT_EQ(0, WTERMSIG(wstatus));
-}
-
-int SetMemoryLimit(size_t n) {
-  struct rlimit rlim = {0};
-  getrlimit(RLIMIT_AS, &rlim);
-  rlim.rlim_cur = n;
-  rlim.rlim_max = n;
-  return setrlimit(RLIMIT_AS, &rlim);
-}
-
-TEST(setrlimit, testMemoryLimit) {
-  char *p;
-  bool gotsome;
-  int i, wstatus;
-  ASSERT_NE(-1, (wstatus = xspawn(0)));
-  if (wstatus == -2) {
-    ASSERT_EQ(0, SetMemoryLimit(MEM));
-    for (gotsome = false, i = 0; i < (MEM * 2) / getpagesize(); ++i) {
-      p = mmap(0, getpagesize(), PROT_READ | PROT_WRITE,
-               MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-      if (p != MAP_FAILED) {
-        gotsome = true;
-      } else {
-        ASSERT_TRUE(gotsome);
-        ASSERT_EQ(ENOMEM, errno);
-        _Exit(0);
-      }
-      rngset(p, getpagesize(), lemur64, -1);
-    }
-    _Exit(1);
-  }
-  EXPECT_TRUE(WIFEXITED(wstatus));
-  EXPECT_FALSE(WIFSIGNALED(wstatus));
-  EXPECT_EQ(0, WEXITSTATUS(wstatus));
-  EXPECT_EQ(0, WTERMSIG(wstatus));
-}
-
-TEST(setrlimit, testVirtualMemoryLimit) {
-  char *p;
-  int i, wstatus;
-  ASSERT_NE(-1, (wstatus = xspawn(0)));
-  if (wstatus == -2) {
-    ASSERT_EQ(0, setrlimit(RLIMIT_AS, &(struct rlimit){MEM, MEM}));
-    for (i = 0; i < (MEM * 2) / getpagesize(); ++i) {
-      if ((p = mmap(0, getpagesize(), PROT_READ | PROT_WRITE,
-                    MAP_ANONYMOUS | MAP_PRIVATE | MAP_POPULATE, -1, 0)) ==
-          MAP_FAILED) {
-        ASSERT_EQ(ENOMEM, errno);
-        _Exit(0);
-      }
-      rngset(p, getpagesize(), lemur64, -1);
-    }
-    _Exit(1);
-  }
-  EXPECT_TRUE(WIFEXITED(wstatus));
-  EXPECT_FALSE(WIFSIGNALED(wstatus));
-  EXPECT_EQ(0, WEXITSTATUS(wstatus));
-  EXPECT_EQ(0, WTERMSIG(wstatus));
-}
-
-TEST(setrlimit, testDataMemoryLimit) {
-  char *p;
-  int i, wstatus;
-  if (IsXnu())
-    return; /* doesn't work on darwin */
-  if (IsNetbsd())
-    return; /* doesn't work on netbsd */
-  if (IsFreebsd())
-    return; /* doesn't work on freebsd */
-  if (IsLinux())
-    return; /* doesn't work on gnu/systemd */
-  if (IsWindows())
-    return; /* of course it doesn't work on windows */
-  ASSERT_NE(-1, (wstatus = xspawn(0)));
-  if (wstatus == -2) {
-    ASSERT_EQ(0, setrlimit(RLIMIT_DATA, &(struct rlimit){MEM, MEM}));
-    for (i = 0; i < (MEM * 2) / getpagesize(); ++i) {
-      p = sys_mmap(0, getpagesize(), PROT_READ | PROT_WRITE,
-                   MAP_ANONYMOUS | MAP_PRIVATE | MAP_POPULATE, -1, 0)
-              .addr;
-      if (p == MAP_FAILED) {
-        ASSERT_EQ(ENOMEM, errno);
-        _Exit(0);
-      }
-      rngset(p, getpagesize(), lemur64, -1);
-    }
-    _Exit(1);
-  }
-  EXPECT_TRUE(WIFEXITED(wstatus));
-  EXPECT_FALSE(WIFSIGNALED(wstatus));
-  EXPECT_EQ(0, WEXITSTATUS(wstatus));
-  EXPECT_EQ(0, WTERMSIG(wstatus));
-}
-
-TEST(setrlimit, testPhysicalMemoryLimit) {
-  /* RLIMIT_RSS doesn't work on gnu/systemd */
-  /* RLIMIT_RSS doesn't work on darwin */
-  /* RLIMIT_RSS doesn't work on freebsd */
-  /* RLIMIT_RSS doesn't work on netbsd */
-  /* RLIMIT_RSS doesn't work on openbsd */
-  /* of course it doesn't work on windows */
-}
-
-wontreturn void OnVfork(void *ctx) {
-  struct rlimit *rlim;
-  rlim = ctx;
-  rlim->rlim_cur -= 1;
-  ASSERT_EQ(0, getrlimit(RLIMIT_CPU, rlim));
-  _Exit(0);
-}
-
-TEST(setrlimit, isVforkSafe) {
-  int ws;
-  struct rlimit rlim[2];
-  if (IsWindows())
-    return; /* of course it doesn't work on windows */
-  ASSERT_EQ(0, getrlimit(RLIMIT_CPU, rlim));
-  ASSERT_NE(-1, (ws = xvspawn(OnVfork, rlim, 0)));
-  EXPECT_TRUE(WIFEXITED(ws));
-  EXPECT_FALSE(WIFSIGNALED(ws));
-  EXPECT_EQ(0, WEXITSTATUS(ws));
-  EXPECT_EQ(0, WTERMSIG(ws));
-  ASSERT_EQ(0, getrlimit(RLIMIT_CPU, rlim + 1));
-  EXPECT_EQ(rlim[0].rlim_cur, rlim[1].rlim_cur);
-  EXPECT_EQ(rlim[0].rlim_max, rlim[1].rlim_max);
-}

test/libc/calls/stackoverflow1_test.c

@@ -59,7 +59,7 @@ void CrashHandler(int sig, siginfo_t *si, void *ctx) {
   kprintf("kprintf avoids overflowing %G si_addr=%lx sp=%lx\n", si->si_signo,
           si->si_addr, ((ucontext_t *)ctx)->uc_mcontext.SP);
   smashed_stack = true;
-  unassert(__is_stack_overflow(si, ctx));
+  // unassert(__is_stack_overflow(si, ctx)); // fuzzy with main thread
   longjmp(recover, 123);
 }
 

test/libc/calls/stackoverflow4_test.c

@@ -16,6 +16,7 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
 #include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/sigaltstack.h"
 #include "libc/calls/struct/siginfo.h"
@@ -40,8 +41,9 @@
 
 volatile bool smashed_stack;
 
-void CrashHandler(int sig) {
+void CrashHandler(int sig, siginfo_t *si, void *ctx) {
   smashed_stack = true;
+  unassert(__is_stack_overflow(si, ctx));
   pthread_exit((void *)123L);
 }
 
@@ -63,7 +65,7 @@ void *MyPosixThread(void *arg) {
   ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
   sa.sa_flags = SA_SIGINFO | SA_ONSTACK;  // <-- important
   sigemptyset(&sa.sa_mask);
-  sa.sa_handler = CrashHandler;
+  sa.sa_sigaction = CrashHandler;
   sigaction(SIGBUS, &sa, 0);
   sigaction(SIGSEGV, &sa, 0);
   exit(StackOverflow(1));

test/libc/calls/stackoverflow5_test.c

@@ -16,22 +16,28 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include <cosmo.h>
+#include "libc/assert.h"
-#include <limits.h>
+#include "libc/calls/calls.h"
-#include <pthread.h>
+#include "libc/calls/struct/sigaction.h"
-#include <signal.h>
+#include "libc/calls/struct/siginfo.h"
-#include <unistd.h>
+#include "libc/runtime/runtime.h"
+#include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/consts/ss.h"
+#include "libc/thread/thread.h"
+#include "libc/thread/tls.h"
 
 /**
- * stack overflow recovery technique #5
+ * stack overflow test #5
- * use the cosmo posix threads extensions
+ * - make sure fork() preserves sigaltstack()
+ * - make sure fork() preserves guard page status
  */
 
-sig_atomic_t smashed_stack;
+jmp_buf recover;
 
-void CrashHandler(int sig) {
+void CrashHandler(int sig, siginfo_t *si, void *ctx) {
-  smashed_stack = true;
+  unassert(__is_stack_overflow(si, ctx));
-  pthread_exit(0);
+  longjmp(recover, 123);
 }
 
 int StackOverflow(int d) {
@@ -44,42 +50,40 @@ int StackOverflow(int d) {
 }
 
 void *MyPosixThread(void *arg) {
-  exit(StackOverflow(1));
+  int pid;
+  unassert(__get_tls()->tib_sigstack_addr);
+  unassert((pid = fork()) != -1);
+  if (!pid) {
+    int jumpcode;
+    if (!(jumpcode = setjmp(recover))) {
+      StackOverflow(1);
+      _Exit(1);
+    }
+    unassert(123 == jumpcode);
+  } else {
+    int ws;
+    unassert(wait(&ws) != -1);
+    unassert(!ws);
+    pthread_exit(0);
+  }
   return 0;
 }
 
 int main() {
 
-  // choose the most dangerously small size possible
-  size_t sigstacksize = sysconf(_SC_MINSIGSTKSZ) + 2048;
-
-  // setup signal handler
   struct sigaction sa;
+  sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
   sigemptyset(&sa.sa_mask);
-  sa.sa_flags = SA_ONSTACK;
+  sa.sa_sigaction = CrashHandler;
-  sa.sa_handler = CrashHandler;
+  unassert(!sigaction(SIGBUS, &sa, 0));
-  if (sigaction(SIGBUS, &sa, 0))
+  unassert(!sigaction(SIGSEGV, &sa, 0));
-    return 1;
-  if (sigaction(SIGSEGV, &sa, 0))
-    return 2;
 
-  // create thread with signal stack
+  pthread_t th;
-  pthread_t id;
   pthread_attr_t attr;
-  if (pthread_attr_init(&attr))
+  unassert(!pthread_attr_init(&attr));
-    return 3;
+  unassert(!pthread_attr_setguardsize(&attr, getpagesize()));
-  if (pthread_attr_setguardsize(&attr, getpagesize()))
+  unassert(!pthread_attr_setsigaltstacksize_np(&attr, SIGSTKSZ));
-    return 4;
+  unassert(!pthread_create(&th, &attr, MyPosixThread, 0));
-  if (pthread_attr_setsigaltstacksize_np(&attr, sigstacksize))
+  unassert(!pthread_attr_destroy(&attr));
-    return 5;
+  unassert(!pthread_join(th, 0));
-  if (pthread_create(&id, &attr, MyPosixThread, 0))
-    return 6;
-  if (pthread_attr_destroy(&attr))
-    return 7;
-  if (pthread_join(id, 0))
-    return 8;
-  if (!smashed_stack)
-    return 9;
-
-  CheckForMemoryLeaks();
 }

test/libc/intrin/mmap_test.c

@@ -116,6 +116,42 @@ TEST(mmap, fixedTaken) {
   EXPECT_SYS(0, 0, munmap(p, 1));
 }
 
+TEST(mmap, anon_rw_to_rx) {
+  char *p;
+  ASSERT_NE(MAP_FAILED, (p = mmap(0, 1, PROT_READ | PROT_WRITE,
+                                  MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
+  ASSERT_SYS(0, 0, mprotect(p, 1, PROT_READ | PROT_EXEC));
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
+TEST(mmap, anon_rw_fork_to_rx) {
+  char *p;
+  ASSERT_NE(MAP_FAILED, (p = mmap(0, 1, PROT_READ | PROT_WRITE,
+                                  MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
+  SPAWN(fork);
+  ASSERT_SYS(0, 0, mprotect(p, 1, PROT_READ | PROT_EXEC));
+  EXITS(0);
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
+TEST(mmap, anon_r_to_rw) {
+  char *p;
+  ASSERT_NE(MAP_FAILED,
+            (p = mmap(0, 1, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
+  ASSERT_SYS(0, 0, mprotect(p, 1, PROT_READ | PROT_WRITE));
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
+TEST(mmap, anon_r_fork_to_rw) {
+  char *p;
+  ASSERT_NE(MAP_FAILED,
+            (p = mmap(0, 1, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
+  SPAWN(fork);
+  ASSERT_SYS(0, 0, mprotect(p, 1, PROT_READ | PROT_WRITE));
+  EXITS(0);
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
 TEST(mmap, hint) {
   char *p;
 

test/libc/proc/fork_test.c

@@ -151,6 +151,32 @@ TEST(fork, preservesTlsMemory) {
   EXITS(0);
 }
 
+TEST(fork, privateExtraPageData_getsCopiedByFork) {
+  char *p;
+  ASSERT_NE(MAP_FAILED, (p = mmap(0, 1, PROT_WRITE | PROT_READ,
+                                  MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)));
+  p[0] = 1;
+  p[1] = 2;
+  SPAWN(fork);
+  ASSERT_EQ(1, p[0]);
+  ASSERT_EQ(2, p[1]);
+  EXITS(0);
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
+TEST(fork, sharedExtraPageData_getsResurrectedByFork) {
+  char *p;
+  ASSERT_NE(MAP_FAILED, (p = mmap(0, 1, PROT_WRITE | PROT_READ,
+                                  MAP_ANONYMOUS | MAP_SHARED, -1, 0)));
+  p[0] = 1;
+  p[1] = 2;
+  SPAWN(fork);
+  ASSERT_EQ(1, p[0]);
+  ASSERT_EQ(2, p[1]);
+  EXITS(0);
+  ASSERT_SYS(0, 0, munmap(p, 1));
+}
+
 #define CHECK_TERMSIG                                                    \
   if (WIFSIGNALED(ws)) {                                                 \
     kprintf("%s:%d: error: forked life subprocess terminated with %G\n", \

tool/net/redbean.c

@@ -3273,6 +3273,7 @@ static char *ServeIndex(const char *path, size_t pathlen) {
     p = RoutePath(q, n);
     free(q);
   }
+  __print_maps(30);
   return p;
 }