Share file offset across execve() on Windows

This is a breaking change. It defines the new environment variable named
_COSMO_FDS_V2 which is used for inheriting non-stdio file descriptors on
execve() or posix_spawn(). No effort has been spent thus far integrating
with the older variable. If a new binary launches the older ones or vice
versa they'll only be able to pass stdin / stdout / stderr to each other
therefore it's important that you upgrade all your cosmo binaries if you
depend on this functionality. You'll be glad you did because inheritance
of file descriptors is more aligned with the POSIX standard than before.

libc/runtime/mapanon.c

@@ -1,66 +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/calls/calls.h"
-#include "libc/errno.h"
-#include "libc/intrin/weaken.h"
-#include "libc/runtime/runtime.h"
-#include "libc/sysv/consts/map.h"
-#include "libc/sysv/consts/prot.h"
-
-/**
- * Helper function for allocating anonymous mapping.
- *
- * This function is equivalent to:
- *
- *     mmap(NULL, mapsize, PROT_READ | PROT_WRITE,
- *          MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- *
- * If mmap() fails, possibly because the parent process did this:
- *
- *     if (!vfork()) {
- *       setrlimit(RLIMIT_AS, &(struct rlimit){maxbytes, maxbytes});
- *       execv(prog, (char *const[]){prog, 0});
- *     }
- *     wait(0);
- *
- * Then this function will call:
- *
- *     __oom_hook(size);
- *
- * If it's linked. The LIBC_TESTLIB library provides an implementation,
- * which can be installed as follows:
- *
- *     int main() {
- *         InstallQuotaHandlers();
- *         // ...
- *     }
- *
- * That is performed automatically for unit test executables.
- *
- * @return memory map address on success, or null w/ errno
- */
-void *_mapanon(size_t size) {
-  void *m;
-  m = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-  if (m != MAP_FAILED)
-    return m;
-  if (errno == ENOMEM && _weaken(__oom_hook))
-    _weaken(__oom_hook)(size);
-  return 0;
-}

libc/runtime/straceinit.greg.c

@@ -28,9 +28,8 @@
  */
 textstartup int __strace_init(int argc, char **argv, char **envp, long *auxv) {
   /* asan isn't initialized yet at runlevel 300 */
-  if ((__intercept_flag(&argc, argv, "--strace") ||
-       __atoul(nulltoempty(__getenv(envp, "STRACE").s))) &&
-      !issetugid()) {
+  if (__intercept_flag(&argc, argv, "--strace") ||
+      __atoul(nulltoempty(__getenv(envp, "STRACE").s))) {
     strace_enabled(+1);
   }
   return (__argc = argc);

libc/runtime/winmain.greg.c

@@ -21,6 +21,7 @@
 #include "libc/calls/sig.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/intrin/dll.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/intrin/maps.h"
 #include "libc/intrin/nomultics.h"
 #include "libc/intrin/weaken.h"

libc/runtime/zipos-get.c

@@ -21,6 +21,7 @@
 #include "libc/calls/metalfile.internal.h"
 #include "libc/calls/struct/stat.h"
 #include "libc/cosmo.h"
+#include "libc/dce.h"
 #include "libc/fmt/conv.h"
 #include "libc/intrin/cmpxchg.h"
 #include "libc/intrin/promises.h"
@@ -62,15 +63,11 @@ static void __zipos_dismiss(uint8_t *map, const uint8_t *cdir, long pg) {
   }
 
   // unmap the executable portion beneath the local files
-  mo = ROUNDDOWN(lo, __gransize);
-  if (mo)
-    munmap(map, mo);
-
-  // this is supposed to reduce our rss usage but does it really?
-  lo = ROUNDDOWN(lo, pg);
-  hi = MIN(ROUNDUP(hi, pg), ROUNDDOWN(c, pg));
-  if (hi > lo)
-    posix_madvise(map + lo, hi - lo, POSIX_MADV_DONTNEED);
+  if (!IsWindows()) {
+    mo = ROUNDDOWN(lo, __gransize);
+    if (mo)
+      munmap(map, mo);
+  }
 }
 
 static int __zipos_compare_names(const void *a, const void *b, void *c) {