Eliminate some flakes

- Get ASAN working on Windows.

- Deleting directories and then recreating them with the same name in a
  short period of time appears to be a no-no on Windows.

- There's no reason to call FlushFileBuffers on close() for pipes, and
  it's harmful since it might block indefinitely for no good reason.

libc/calls/calls.mk

@@ -44,7 +44,6 @@ LIBC_CALLS_A_DIRECTDEPS =				\
 	LIBC_NT_ADVAPI32				\
 	LIBC_NT_KERNEL32				\
 	LIBC_NT_NTDLL					\
-	LIBC_RAND					\
 	LIBC_STR					\
 	LIBC_STUBS					\
 	LIBC_SYSV_CALLS					\

libc/calls/close-nt.c

@@ -17,13 +17,15 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/internal.h"
+#include "libc/nt/enum/filetype.h"
 #include "libc/nt/files.h"
 #include "libc/nt/runtime.h"
 #include "libc/sysv/errfuns.h"
 
 textwindows int close$nt(int fd) {
   bool32 ok;
-  if (g_fds.p[fd].kind == kFdFile) {
+  if (g_fds.p[fd].kind == kFdFile &&
+      GetFileType(g_fds.p[fd].handle) == kNtFileTypeDisk) {
     /*
      * Like Linux, closing a file on Windows doesn't guarantee it's
      * immediately synced to disk. But unlike Linux, this could cause
@@ -32,6 +34,8 @@ textwindows int close$nt(int fd) {
     FlushFileBuffers(g_fds.p[fd].handle);
   }
   ok = CloseHandle(g_fds.p[fd].handle);
-  if (g_fds.p[fd].kind == kFdConsole) ok &= CloseHandle(g_fds.p[fd].extra);
+  if (g_fds.p[fd].kind == kFdConsole) {
+    ok &= CloseHandle(g_fds.p[fd].extra);
+  }
   return ok ? 0 : __winerr();
 }

libc/calls/close.c

@@ -53,8 +53,7 @@ int close(int fd) {
     rc = ebadf();
   }
   if (!__vforked && fd < g_fds.n) {
-    g_fds.p[fd].kind = kFdEmpty;
-    g_fds.f = MIN(g_fds.f, fd);
+    __releasefd(fd);
   }
   return rc;
 }

libc/calls/dup-nt.c

@@ -30,17 +30,18 @@
  */
 textwindows int dup$nt(int oldfd, int newfd, int flags) {
   int64_t proc;
-  if (!__isfdkind(oldfd, kFdFile)) return ebadf();
+  if (oldfd < 0) return einval();
+  if (oldfd >= g_fds.n ||
+      (g_fds.p[oldfd].kind != kFdFile && g_fds.p[oldfd].kind != kFdSocket &&
+       g_fds.p[oldfd].kind != kFdConsole)) {
+    return ebadf();
+  }
   if (newfd == -1) {
-    if ((newfd = __getemptyfd()) == -1) {
-      return -1;
-    }
-  } else if (__ensurefds(newfd) != -1) {
-    if (g_fds.p[newfd].kind != kFdEmpty) {
-      close(newfd);
-    }
+    if ((newfd = __reservefd()) == -1) return -1;
   } else {
-    return -1;
+    if (__ensurefds(newfd) == -1) return -1;
+    if (g_fds.p[newfd].kind) close(newfd);
+    g_fds.p[newfd].kind = kFdReserved;
   }
   proc = GetCurrentProcess();
   if (DuplicateHandle(proc, g_fds.p[oldfd].handle, proc, &g_fds.p[newfd].handle,
@@ -49,6 +50,7 @@ textwindows int dup$nt(int oldfd, int newfd, int flags) {
     g_fds.p[newfd].flags = flags;
     return newfd;
   } else {
+    __releasefd(newfd);
     return __winerr();
   }
 }

libc/calls/ensurefds.c

@@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
+#include "libc/bits/bits.h"
 #include "libc/bits/weaken.h"
 #include "libc/calls/internal.h"
 #include "libc/mem/mem.h"
@@ -24,24 +25,29 @@
 #include "libc/sysv/errfuns.h"
 
 int __ensurefds(int fd) {
-  size_t n;
-  struct Fd *p;
-  if (fd < g_fds.n) return fd;
-  if (weaken(malloc)) {
-    n = MAX(fd + 1, g_fds.n + (g_fds.n << 1));
-    if ((p = weaken(malloc)(n * sizeof(*p)))) {
-      memcpy(p, g_fds.p, g_fds.n * sizeof(*p));
-      memset(p + g_fds.n, 0, (n - g_fds.n) * sizeof(*p));
-      if (g_fds.p != g_fds.__init_p && weaken(free)) {
-        weaken(free)(g_fds.p);
+  size_t n1, n2;
+  struct Fd *p1, *p2;
+  for (;;) {
+    p1 = g_fds.p;
+    n1 = g_fds.n;
+    if (fd < n1) return fd;
+    if (weaken(malloc)) {
+      n2 = MAX(fd + 1, n1 + (n1 << 1));
+      if ((p2 = weaken(malloc)(n2 * sizeof(*p1)))) {
+        memcpy(p2, p1, n1 * sizeof(*p1));
+        memset(p2 + n1, 0, (n2 - n1) * sizeof(*p1));
+        if (p1 != g_fds.__init_p && weaken(free)) weaken(free)(p1);
+        if (cmpxchg(&g_fds.p, p1, p2)) {
+          g_fds.n = n2;
+          return fd;
+        } else if (weaken(free)) {
+          weaken(free)(p2);
+        }
+      } else {
+        return enomem();
       }
-      g_fds.p = p;
-      g_fds.n = n;
-      return fd;
     } else {
-      return enomem();
+      return emfile();
     }
-  } else {
-    return emfile();
   }
 }

libc/calls/internal.h

@@ -52,6 +52,7 @@ struct Fds {
       kFdSerial,
       kFdZip,
       kFdEpoll,
+      kFdReserved,
     } kind;
     unsigned flags;
   } * p;
@@ -68,7 +69,8 @@ hidden extern struct NtSystemInfo g_ntsysteminfo;
 hidden extern struct NtStartupInfo g_ntstartupinfo;
 hidden extern const struct NtSecurityAttributes kNtIsInheritable;
 
-ssize_t __getemptyfd(void) hidden;
+int __reservefd(void) hidden;
+void __releasefd(int) hidden;
 int __ensurefds(int) hidden;
 void __removefd(int) hidden;
 

libc/calls/ioctl-tcsets-nt.c

@@ -22,7 +22,6 @@
 #include "libc/nt/console.h"
 #include "libc/nt/enum/consolemodeflags.h"
 #include "libc/nt/enum/version.h"
-#include "libc/nt/struct/teb.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/termios.h"
 #include "libc/sysv/errfuns.h"

libc/calls/isdebuggerpresent.c

@@ -32,7 +32,11 @@
 
 #define kBufSize    1024
 #define kProcStatus "/proc/self/status"
-_Alignas(16) static const char kGdbPid[] = "TracerPid:\t";
+#define kPid        "TracerPid:\t"
+
+static noasan int NtBeingDebugged(void) {
+  return NtGetPeb()->BeingDebugged;
+}
 
 /**
  * Determines if gdb, strace, windbg, etc. is controlling process.
@@ -42,19 +46,18 @@ int IsDebuggerPresent(bool force) {
   int fd, res;
   ssize_t got;
   char buf[1024];
-  res = 0;
+  res = false;
   if (!force) {
     if (getenv("HEISENDEBUG")) return false;
     if (IsGenuineCosmo()) return false;
   }
   if (IsWindows()) {
-    res = NtGetPeb()->BeingDebugged;
+    res = NtBeingDebugged();
   } else if (IsLinux()) {
     if ((fd = openat$sysv(AT_FDCWD, kProcStatus, O_RDONLY, 0)) != -1) {
-      if ((got = read$sysv(fd, buf, sizeof(buf) - sizeof(kGdbPid))) != -1) {
+      if ((got = read$sysv(fd, buf, sizeof(buf) - sizeof(kPid))) != -1) {
         buf[got] = '\0';
-        res =
-            atoi(firstnonnull(strstr(buf, kGdbPid), kGdbPid) + strlen(kGdbPid));
+        res = atoi(firstnonnull(strstr(buf, kPid), kPid) + strlen(kPid));
       }
       close$sysv(fd);
     }

libc/calls/mkntcmdline.c

@@ -37,8 +37,8 @@
  * @kudos Daniel Colascione for teaching how to quote
  * @see libc/runtime/dosargv.c
  */
-textwindows int mkntcmdline(char16_t cmdline[ARG_MAX], const char *prog,
-                            char *const argv[]) {
+textwindows noasan int mkntcmdline(char16_t cmdline[ARG_MAX], const char *prog,
+                                   char *const argv[]) {
   char *arg;
   uint64_t w;
   wint_t x, y;

libc/calls/mkntenvblock.c

@@ -29,21 +29,18 @@
 #include "libc/str/utf16.h"
 #include "libc/sysv/errfuns.h"
 
-static int CompareStrings(const char *l, const char *r) {
+static noasan int CompareStrings(const char *l, const char *r) {
   size_t i = 0;
   while (l[i] == r[i] && r[i]) ++i;
   return (l[i] & 0xff) - (r[i] & 0xff);
 }
 
-static void SortStrings(char **a, size_t n) {
-  char *t;
-  size_t i, j;
-  for (i = 1; i < n; ++i) {
-    for (t = a[i], j = i; j > 0 && CompareStrings(t, a[j - 1]) < 0; --j) {
-      a[j] = a[j - 1];
-    }
-    a[j] = t;
+static noasan void InsertString(char **a, size_t i, char *s) {
+  size_t j;
+  for (j = i; j > 0 && CompareStrings(s, a[j - 1]) < 0; --j) {
+    a[j] = a[j - 1];
   }
+  a[j] = s;
 }
 
 /**
@@ -57,8 +54,9 @@ static void SortStrings(char **a, size_t n) {
  * @return 0 on success, or -1 w/ errno
  * @error E2BIG if total number of shorts exceeded ARG_MAX (0x8000)
  */
-textwindows int mkntenvblock(char16_t envvars[ARG_MAX], char *const envp[],
-                             const char *extravar) {
+textwindows noasan int mkntenvblock(char16_t envvars[ARG_MAX],
+                                    char *const envp[], const char *extravar) {
+  char *t;
   axdx_t rc;
   uint64_t w;
   char **vars;
@@ -66,9 +64,8 @@ textwindows int mkntenvblock(char16_t envvars[ARG_MAX], char *const envp[],
   size_t i, j, k, n, m;
   for (n = 0; envp[n];) n++;
   vars = alloca((n + 1) * sizeof(char *));
-  memcpy(vars, envp, n * sizeof(char *));
-  if (extravar) vars[n++] = extravar;
-  SortStrings(vars, n);
+  for (i = 0; i < n; ++i) InsertString(vars, i, envp[i]);
+  if (extravar) InsertString(vars, n++, extravar);
   for (k = i = 0; i < n; ++i) {
     j = 0;
     do {

libc/calls/open-nt.c

@@ -112,11 +112,16 @@ static textwindows ssize_t open$nt$file(int dirfd, const char *file,
 
 textwindows ssize_t open$nt(int dirfd, const char *file, uint32_t flags,
                             int32_t mode) {
-  size_t fd;
-  if ((fd = __getemptyfd()) == -1) return -1;
+  int fd;
+  ssize_t rc;
+  if ((fd = __reservefd()) == -1) return -1;
   if ((flags & O_ACCMODE) == O_RDWR && !strcmp(file, kNtMagicPaths.devtty)) {
-    return open$nt$console(dirfd, &kNtMagicPaths, flags, mode, fd);
+    rc = open$nt$console(dirfd, &kNtMagicPaths, flags, mode, fd);
   } else {
-    return open$nt$file(dirfd, file, flags, mode, fd);
+    rc = open$nt$file(dirfd, file, flags, mode, fd);
   }
+  if (rc == -1) {
+    __releasefd(fd);
+  }
+  return rc;
 }

libc/calls/open.c

@@ -31,7 +31,7 @@
  * @asyncsignalsafe
  * @vforksafe
  */
-nodiscard int open(const char *file, int flags, ...) {
+int open(const char *file, int flags, ...) {
   va_list va;
   unsigned mode;
   va_start(va, flags);

libc/calls/openanon.c

@@ -67,8 +67,8 @@ static int openanon$impl(const char *name, unsigned flags,
     }
     return fd;
   } else {
-    if ((fd = __getemptyfd()) != -1 &&
-        (g_fds.p[fd].handle = CreateFileA(
+    if ((fd = __reservefd()) == -1) return -1;
+    if ((g_fds.p[fd].handle = CreateFileA(
              pathbuf, kNtGenericRead | kNtGenericWrite, kNtFileShareExclusive,
              &kNtIsInheritable, kNtCreateAlways,
              (kNtFileAttributeNotContentIndexed | kNtFileAttributeNormal |
@@ -78,6 +78,7 @@ static int openanon$impl(const char *name, unsigned flags,
       g_fds.p[fd].flags = flags;
       return fd;
     } else {
+      __releasefd(fd);
       return __winerr();
     }
   }

libc/calls/pipe-nt.c

@@ -58,16 +58,19 @@ textwindows int pipe$nt(int pipefd[2], unsigned flags) {
   int reader, writer;
   char16_t pipename[64];
   CreatePipeName(pipename);
+  if ((reader = __reservefd()) == -1) return -1;
+  if ((writer = __reservefd()) == -1) {
+    __releasefd(reader);
+    return -1;
+  }
   if ((hin = CreateNamedPipe(pipename, kNtPipeAccessInbound,
                              kNtPipeWait | kNtPipeReadmodeByte, 1, 65536, 65536,
                              0, &kNtIsInheritable)) != -1) {
     if ((hout = CreateFile(pipename, kNtGenericWrite, kNtFileShareWrite,
                            &kNtIsInheritable, kNtOpenExisting, 0, 0)) != -1) {
-      reader = __getemptyfd();
       g_fds.p[reader].kind = kFdFile;
       g_fds.p[reader].flags = flags;
       g_fds.p[reader].handle = hin;
-      writer = __getemptyfd();
       g_fds.p[writer].kind = kFdFile;
       g_fds.p[writer].flags = flags;
       g_fds.p[writer].handle = hout;
@@ -78,5 +81,6 @@ textwindows int pipe$nt(int pipefd[2], unsigned flags) {
       CloseHandle(hin);
     }
   }
+  __releasefd(reader);
   return __winerr();
 }

libc/calls/releasefd.c

@@ -0,0 +1,29 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net 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/bits/bits.h"
+#include "libc/calls/internal.h"
+
+void __releasefd(int fd) {
+  int x;
+  g_fds.p[fd].kind = kFdEmpty;
+  do {
+    x = g_fds.f;
+    if (fd >= x) break;
+  } while (!cmpxchg(&g_fds.f, x, fd));
+}

libc/calls/reservefd.c

@@ -24,11 +24,16 @@
 /**
  * Finds open file descriptor slot.
  */
-ssize_t __getemptyfd(void) {
-  for (; g_fds.f < g_fds.n; ++g_fds.f) {
-    if (g_fds.p[g_fds.f].kind == kFdEmpty) {
-      return g_fds.f;
+int __reservefd(void) {
+  int fd;
+  for (;;) {
+    fd = g_fds.f;
+    if (fd >= g_fds.n) {
+      if (__ensurefds(fd) == -1) return -1;
+    }
+    cmpxchg(&g_fds.f, fd, fd + 1);
+    if (cmpxchg(&g_fds.p[fd].kind, kFdEmpty, kFdReserved)) {
+      return fd;
     }
   }
-  return __ensurefds(g_fds.f);
 }

libc/calls/sigaction.c

@@ -19,6 +19,7 @@
 #include "libc/bits/bits.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/sigbits.h"
 #include "libc/calls/struct/sigaction-freebsd.internal.h"
 #include "libc/calls/struct/sigaction-linux.internal.h"
 #include "libc/calls/struct/sigaction-openbsd.internal.h"
@@ -128,9 +129,8 @@ int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
                  sizeof(struct sigaction) > sizeof(struct sigaction$openbsd));
   int rc, rva, oldrva;
   struct sigaction *ap, copy;
-  if (!(0 < sig && sig < NSIG) || sig == SIGKILL || sig == SIGSTOP) {
-    return einval();
-  }
+  if (!(0 < sig && sig < NSIG)) return einval();
+  if (sig == SIGKILL || sig == SIGSTOP) return einval();
   if (!act) {
     rva = (int32_t)(intptr_t)SIG_DFL;
   } else if ((intptr_t)act->sa_handler < kSigactionMinRva) {
@@ -141,6 +141,9 @@ int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
   } else {
     return efault();
   }
+  if (__vforked && rva != (intptr_t)SIG_DFL && rva != (intptr_t)SIG_IGN) {
+    return einval();
+  }
   if (!IsWindows()) {
     if (!IsMetal()) {
       if (act) {
@@ -149,16 +152,13 @@ int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
         if (IsXnu()) {
           ap->sa_restorer = (void *)&xnutrampoline;
           ap->sa_handler = (void *)&xnutrampoline;
-        } else {
-          if (IsLinux()) {
-            if (!(ap->sa_flags & SA_RESTORER)) {
-              ap->sa_flags |= SA_RESTORER;
-              ap->sa_restorer = &__restore_rt;
-            }
-          }
-          if (rva >= kSigactionMinRva) {
-            ap->sa_sigaction = (sigaction_f)__sigenter;
+        } else if (IsLinux()) {
+          if (!(ap->sa_flags & SA_RESTORER)) {
+            ap->sa_flags |= SA_RESTORER;
+            ap->sa_restorer = &__restore_rt;
           }
+        } else if (rva >= kSigactionMinRva) {
+          ap->sa_sigaction = (sigaction_f)__sigenter;
         }
         sigaction$cosmo2native((union metasigaction *)ap);
       } else {
@@ -178,7 +178,7 @@ int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
     }
     rc = 0;
   }
-  if (rc != -1) {
+  if (rc != -1 && !__vforked) {
     if (oldact) {
       oldrva = __sighandrvas[sig];
       oldact->sa_sigaction = (sigaction_f)(

libc/calls/sigenter.S

@@ -20,7 +20,7 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-/	System Five signal handler.
+/	BSD signal handler.
 /
 /	This is needed because (1) a signal is allowed to trigger at
 /	just about any time, and leaf functions (e.g. memcpy) aren't

libc/calls/winerr.greg.c

@@ -28,7 +28,7 @@
  * @return -1 w/ few exceptions
  * @note this is a code-size saving device
  */
-privileged int64_t __winerr(void) {
+privileged noasan int64_t __winerr(void) {
   if (IsWindows()) {
     errno = GetLastError();
     return -1;

libc/calls/write-nt.c

@@ -42,7 +42,6 @@ textwindows ssize_t write$nt(struct Fd *fd, const struct iovec *iov,
                 iovlen ? clampio(iov[0].iov_len) : 0, &wrote,
                 offset2overlap(opt_offset, &overlap))) {
     if (!wrote) assert(!SumIovecLen(iov, iovlen));
-    FlushFileBuffers(fd->handle);
     return wrote;
   } else {
     return __winerr();