Fix flakes in runitd and popen_test

libc/calls/interrupts-nt.c

@@ -34,17 +34,27 @@
 #include "libc/thread/tls.h"
 
 textwindows int _check_interrupts(bool restartable, struct Fd *fd) {
-  int rc;
+  int e, rc;
+  e = errno;
   if (_weaken(pthread_testcancel_np) &&
       (rc = _weaken(pthread_testcancel_np)())) {
     errno = rc;
     return -1;
   }
-  if (_weaken(_check_sigalrm)) _weaken(_check_sigalrm)();
-  if (!__tls_enabled || !(__get_tls()->tib_flags & TIB_FLAG_TIME_CRITICAL)) {
-    if (_weaken(_check_sigchld)) _weaken(_check_sigchld)();
-    if (fd && _weaken(_check_sigwinch)) _weaken(_check_sigwinch)(fd);
+  if (_weaken(_check_sigalrm)) {
+    _weaken(_check_sigalrm)();
   }
-  if (_weaken(__sig_check) && _weaken(__sig_check)(restartable)) return eintr();
+  if (!__tls_enabled || !(__get_tls()->tib_flags & TIB_FLAG_TIME_CRITICAL)) {
+    if (_weaken(_check_sigchld)) {
+      _weaken(_check_sigchld)();
+    }
+    if (fd && _weaken(_check_sigwinch)) {
+      _weaken(_check_sigwinch)(fd);
+    }
+  }
+  if (_weaken(__sig_check) && _weaken(__sig_check)(restartable)) {
+    return eintr();
+  }
+  errno = e;
   return 0;
 }

libc/calls/sigaction.c

@@ -479,6 +479,15 @@ static int __sigaction(int sig, const struct sigaction *act,
  * frequently calling sigprocmask() out of an abundance of caution, will
  * no longer need to pay its outrageous cost.
  *
+ * Signal handlers should avoid clobbering global variables like `errno`
+ * because most signals are asynchronous, i.e. the signal handler might
+ * be called at any assembly instruction. If something like a `SIGCHLD`
+ * handler doesn't save / restore the `errno` global when calling wait,
+ * then any i/o logic in the main program that checks `errno` will most
+ * likely break. This is rare in practice, since systems usually design
+ * signals to favor delivery from cancellation points before they block
+ * however that's not guaranteed.
+ *
  * @return 0 on success or -1 w/ errno
  * @see xsigaction() for a much better api
  * @asyncsignalsafe

libc/intrin/createfile.c

@@ -17,12 +17,18 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/nt/createfile.h"
+#include "libc/calls/sig.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/intrin/strace.internal.h"
+#include "libc/nt/errors.h"
+#include "libc/nt/runtime.h"
+#include "libc/nt/synchronization.h"
 #include "libc/nt/thunk/msabi.h"
 
 __msabi extern typeof(CreateFile) *const __imp_CreateFileW;
+__msabi extern typeof(GetLastError) *const __imp_GetLastError;
+__msabi extern typeof(Sleep) *const __imp_Sleep;
 
 /**
  * Opens file on the New Technology.
@@ -36,9 +42,16 @@ textwindows int64_t CreateFile(
     int dwCreationDisposition, uint32_t dwFlagsAndAttributes,
     int64_t opt_hTemplateFile) {
   int64_t hHandle;
+  uint32_t micros = 1;
+TryAgain:
   hHandle = __imp_CreateFileW(lpFileName, dwDesiredAccess, dwShareMode,
                               opt_lpSecurityAttributes, dwCreationDisposition,
                               dwFlagsAndAttributes, opt_hTemplateFile);
+  if (hHandle == -1 && __imp_GetLastError() == kNtErrorPipeBusy) {
+    if (micros >= 1024) __imp_Sleep(micros / 1024);
+    if (micros / 1024 < __SIG_POLLING_INTERVAL_MS) micros <<= 1;
+    goto TryAgain;
+  }
   if (hHandle == -1) __winerr();
   NTTRACE("CreateFile(%#hs, %s, %s, %s, %s, %s, %ld) → %ld% m", lpFileName,
           DescribeNtFileAccessFlags(dwDesiredAccess),

libc/intrin/createnamedpipe.c

@@ -16,14 +16,20 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/sig.internal.h"
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/intrin/strace.internal.h"
+#include "libc/nt/errors.h"
 #include "libc/nt/ipc.h"
+#include "libc/nt/runtime.h"
 #include "libc/nt/struct/securityattributes.h"
+#include "libc/nt/synchronization.h"
 #include "libc/nt/thunk/msabi.h"
 
 __msabi extern typeof(CreateNamedPipe) *const __imp_CreateNamedPipeW;
+__msabi extern typeof(GetLastError) *const __imp_GetLastError;
+__msabi extern typeof(Sleep) *const __imp_Sleep;
 
 /**
  * Creates pipe.
@@ -37,9 +43,16 @@ textwindows int64_t CreateNamedPipe(
     uint32_t nDefaultTimeOutMs,
     const struct NtSecurityAttributes *opt_lpSecurityAttributes) {
   int64_t hServer;
+  uint32_t micros = 1;
+TryAgain:
   hServer = __imp_CreateNamedPipeW(lpName, dwOpenMode, dwPipeMode,
                                    nMaxInstances, nOutBufferSize, nInBufferSize,
                                    nDefaultTimeOutMs, opt_lpSecurityAttributes);
+  if (hServer == -1 && __imp_GetLastError() == kNtErrorPipeBusy) {
+    if (micros >= 1024) __imp_Sleep(micros / 1024);
+    if (micros / 1024 < __SIG_POLLING_INTERVAL_MS) micros <<= 1;
+    goto TryAgain;
+  }
   if (hServer == -1) __winerr();
   NTTRACE("CreateNamedPipe(%#hs, %s, %s, %u, %'u, %'u, %'u, %s) → %ld% m",
           lpName, DescribeNtPipeOpenFlags(dwOpenMode),

libc/runtime/cosmo2.c

@@ -131,10 +131,14 @@ textstartup void cosmo(long *sp, struct Syslib *m1) {
   __mmi_lock_obj._type = PTHREAD_MUTEX_RECURSIVE;
 
   // record system provided stack to memory manager
+  // todo: how do we get the real size of the stack
+  //       if `y` is too small mmap will destroy it
+  //       if `x` is too high, backtraces will fail
+  uintptr_t t = (uintptr_t)__builtin_frame_address(0);
   uintptr_t s = (uintptr_t)sp;
   uintptr_t z = GetStackSize() << 1;
   _mmi.i = 1;
-  _mmi.p->x = (s & -z) >> 16;
+  _mmi.p->x = MIN((s & -z) >> 16, (t & -z) >> 16);
   _mmi.p->y = MIN(((s & -z) + (z - 1)) >> 16, INT_MAX);
   _mmi.p->size = z;
   _mmi.p->prot = PROT_READ | PROT_WRITE;

libc/runtime/fork-nt.c

@@ -48,12 +48,14 @@
 #include "libc/nt/runtime.h"
 #include "libc/nt/signals.h"
 #include "libc/nt/struct/ntexceptionpointers.h"
+#include "libc/nt/synchronization.h"
 #include "libc/runtime/internal.h"
 #include "libc/runtime/memtrack.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/runtime/symbols.internal.h"
 #include "libc/sock/internal.h"
 #include "libc/str/str.h"
+#include "libc/sysv/consts/limits.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/prot.h"
@@ -108,20 +110,36 @@ static dontinline textwindows bool ForkIo2(int64_t h, void *buf, size_t n,
 
 static dontinline textwindows bool WriteAll(int64_t h, void *buf, size_t n) {
   bool ok;
+  // kprintf("WriteAll(%ld, %p, %zu);\n", h, buf, n);
   ok = ForkIo2(h, buf, n, WriteFile, "WriteFile", false);
+#ifndef NDEBUG
+  if (ok) ok = ForkIo2(h, &n, sizeof(n), WriteFile, "WriteFile", false);
+#endif
 #ifdef SYSDEBUG
   if (!ok) {
     kprintf("failed to write %zu bytes to forked child: %d\n", n,
             GetLastError());
   }
 #endif
+  // Sleep(10);
   return ok;
 }
 
 static textwindows dontinline void ReadOrDie(int64_t h, void *buf, size_t n) {
+  // kprintf("ReadOrDie(%ld, %p, %zu);\n", h, buf, n);
   if (!ForkIo2(h, buf, n, ReadFile, "ReadFile", true)) {
-    AbortFork("ReadFile");
+    AbortFork("ReadFile1");
   }
+#ifndef NDEBUG
+  size_t got;
+  if (!ForkIo2(h, &got, sizeof(got), ReadFile, "ReadFile", true)) {
+    AbortFork("ReadFile2");
+  }
+  if (got != n) {
+    AbortFork("ReadFile_SIZE_CHECK");
+  }
+#endif
+  // Sleep(10);
 }
 
 static textwindows int64_t MapOrDie(uint32_t prot, uint64_t size) {
@@ -276,6 +294,7 @@ textwindows void WinMainForked(void) {
 
 textwindows int sys_fork_nt(uint32_t dwCreationFlags) {
   jmp_buf jb;
+  uint32_t op;
   uint32_t oldprot;
   char ok, threaded;
   char **args, **args2;
@@ -290,12 +309,10 @@ textwindows int sys_fork_nt(uint32_t dwCreationFlags) {
   tib = __tls_enabled ? __get_tls() : 0;
   if (!setjmp(jb)) {
     pid = untrackpid = __reservefd_unlocked(-1);
-    reader = CreateNamedPipe(CreatePipeName(pipename),
-                             kNtPipeAccessInbound | kNtFileFlagOverlapped,
-                             kNtPipeTypeMessage | kNtPipeReadmodeMessage, 1,
-                             65536, 65536, 0, &kNtIsInheritable);
-    writer = CreateFile(pipename, kNtGenericWrite, 0, 0, kNtOpenExisting,
-                        kNtFileFlagOverlapped, 0);
+    reader = CreateNamedPipe(CreatePipeName(pipename), kNtPipeAccessInbound,
+                             kNtPipeTypeByte | kNtPipeReadmodeByte, 1, PIPE_BUF,
+                             PIPE_BUF, 0, &kNtIsInheritable);
+    writer = CreateFile(pipename, kNtGenericWrite, 0, 0, kNtOpenExisting, 0, 0);
     if (pid != -1 && reader != -1 && writer != -1) {
       p = stpcpy(forkvar, "_FORK=");
       p = FormatUint64(p, reader);
@@ -331,7 +348,6 @@ textwindows int sys_fork_nt(uint32_t dwCreationFlags) {
         }
         for (i = 0; i < _mmi.i && ok; ++i) {
           if ((_mmi.p[i].flags & MAP_TYPE) != MAP_SHARED) {
-            uint32_t op;
             char *p = (char *)((uint64_t)_mmi.p[i].x << 16);
             // XXX: forking destroys thread guard pages currently
             VirtualProtect(

libc/runtime/printargs.c

@@ -464,6 +464,8 @@ dontasan textstartup void __printargs(const char *prologue) {
         PRINT("  - stderr");
       }
       kprintf(prologue);
+      errno = 0;
+      kprintf("    isatty = %d% m\n", isatty(i));
       if (!tcgetwinsize(i, &ws)) {
         kprintf("    ws_row = %d\n", ws.ws_row);
         kprintf("    ws_col = %d\n", ws.ws_col);

libc/sock/bind-nt.c

@@ -18,10 +18,13 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
 #include "libc/calls/struct/fd.internal.h"
+#include "libc/nt/thunk/msabi.h"
 #include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/syscall_fd.internal.h"
 
+__msabi extern typeof(__sys_bind_nt) *const __imp_bind;
+
 textwindows int sys_bind_nt(struct Fd *fd, const void *addr,
                             uint32_t addrsize) {
   unassert(fd->kind == kFdSocket);

libc/sock/closesocket-nt.c

@@ -16,11 +16,14 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/log/backtrace.internal.h"
 #include "libc/mem/mem.h"
+#include "libc/nt/thunk/msabi.h"
+#include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/syscall_fd.internal.h"
 
+__msabi extern typeof(__sys_closesocket_nt) *const __imp_closesocket;
+
 /**
  * Closes socket on Windows.
  *
@@ -30,7 +33,7 @@ textwindows int sys_closesocket_nt(struct Fd *fd) {
   struct SockFd *sockfd;
   sockfd = (struct SockFd *)fd->extra;
   free(sockfd);
-  int rc = __sys_closesocket_nt(fd->handle);
+  int rc = __imp_closesocket(fd->handle);
   if (rc != -1) {
     return 0;
   } else {

libc/sock/dupsockfd.c

@@ -19,13 +19,12 @@
 #include "libc/mem/mem.h"
 #include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
+#include "libc/str/str.h"
 
 textwindows struct SockFd *_dupsockfd(struct SockFd *sockfd) {
   struct SockFd *newsf;
-  if ((newsf = calloc(1, sizeof(struct SockFd)))) {
-    newsf->family = sockfd->family;
-    newsf->type = sockfd->type;
-    newsf->protocol = sockfd->protocol;
+  if ((newsf = malloc(sizeof(struct SockFd)))) {
+    memcpy(newsf, sockfd, sizeof(*sockfd));
   }
   return newsf;
 }

libc/sock/getsockopt-nt.c

@@ -19,6 +19,7 @@
 #include "libc/assert.h"
 #include "libc/calls/struct/timeval.h"
 #include "libc/nt/struct/linger.h"
+#include "libc/nt/thunk/msabi.h"
 #include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/sock.h"
@@ -29,6 +30,8 @@
 #include "libc/sysv/consts/sol.h"
 #include "libc/sysv/errfuns.h"
 
+__msabi extern typeof(__sys_getsockopt_nt) *const __imp_getsockopt;
+
 textwindows int sys_getsockopt_nt(struct Fd *fd, int level, int optname,
                                   void *out_opt_optval,
                                   uint32_t *inout_optlen) {
@@ -63,8 +66,8 @@ textwindows int sys_getsockopt_nt(struct Fd *fd, int level, int optname,
   }
 
   // TODO(jart): Use WSAIoctl?
-  if (__sys_getsockopt_nt(fd->handle, level, optname, out_opt_optval,
-                          inout_optlen) == -1) {
+  if (__imp_getsockopt(fd->handle, level, optname, out_opt_optval,
+                       inout_optlen) == -1) {
     return __winsockerr();
   }
 

libc/sock/internal.h

@@ -80,7 +80,7 @@ int sys_select_nt(int, fd_set *, fd_set *, fd_set *, struct timeval *,
 size_t __iovec2nt(struct NtIovec[hasatleast 16], const struct iovec *, size_t);
 
 void WinSockInit(void);
-int64_t __winsockerr(void) nocallback;
+int64_t __winsockerr(void);
 int __fixupnewsockfd(int, int);
 int64_t __winsockblock(int64_t, unsigned, int64_t, uint32_t);
 struct SockFd *_dupsockfd(struct SockFd *);

libc/sock/listen-nt.c

@@ -17,13 +17,16 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
+#include "libc/nt/thunk/msabi.h"
 #include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/syscall_fd.internal.h"
 
+__msabi extern typeof(__sys_listen_nt) *const __imp_listen;
+
 textwindows int sys_listen_nt(struct Fd *fd, int backlog) {
   npassert(fd->kind == kFdSocket);
-  if (__sys_listen_nt(fd->handle, backlog) != -1) {
+  if (__imp_listen(fd->handle, backlog) != -1) {
     return 0;
   } else {
     return __winsockerr();

libc/sock/recvfrom.c

@@ -34,12 +34,15 @@
 /**
  * Receives data from network.
  *
- * This function blocks unless MSG_DONTWAIT is passed.
- *
  * @param fd is the file descriptor returned by socket()
  * @param buf is where received network data gets copied
  * @param size is the byte capacity of buf
- * @param flags can have MSG_{WAITALL,DONTROUTE,PEEK,OOB}, etc.
+ * @param flags is a bitmask which may contain any of the following:
+ *     - `MSG_DONTWAIT` to force `O_NONBLOCK` behavior for this call
+ *     - `MSG_OOB` is broadly supported (untested by cosmo)
+ *     - `MSG_PEEK` is broadly supported (untested by cosmo)
+ *     - `MSG_WAITALL` is broadly supported (untested by cosmo)
+ *     - `MSG_DONTROUTE` is broadly supported (untested by cosmo)
  * @param opt_out_srcaddr receives the binary ip:port of the data's origin
  * @param opt_inout_srcaddrsize is srcaddr capacity which gets updated
  * @return number of bytes received, 0 on remote close, or -1 w/ errno

libc/sock/setsockopt-nt.c

@@ -20,6 +20,7 @@
 #include "libc/limits.h"
 #include "libc/macros.internal.h"
 #include "libc/nt/struct/linger.h"
+#include "libc/nt/thunk/msabi.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/struct/linger.h"
 #include "libc/sock/syscall_fd.internal.h"
@@ -28,6 +29,8 @@
 #include "libc/sysv/consts/sol.h"
 #include "libc/sysv/errfuns.h"
 
+__msabi extern typeof(__sys_setsockopt_nt) *const __imp_setsockopt;
+
 textwindows int sys_setsockopt_nt(struct Fd *fd, int level, int optname,
                                   const void *optval, uint32_t optlen) {
   int64_t ms, micros;
@@ -70,7 +73,7 @@ textwindows int sys_setsockopt_nt(struct Fd *fd, int level, int optname,
     }
   }
 
-  if (__sys_setsockopt_nt(fd->handle, level, optname, optval, optlen) != -1) {
+  if (__imp_setsockopt(fd->handle, level, optname, optval, optlen) != -1) {
     return 0;
   } else {
     return __winsockerr();

libc/sock/setsockopt.c

@@ -40,10 +40,10 @@ static bool setsockopt_polyfill(int *optname) {
 /**
  * Modifies socket settings.
  *
- * This function is the ultimate rabbit hole. Basic usage:
+ * Basic usage:
  *
- *   int yes = 1;
- *   setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes));
+ *     int yes = 1;
+ *     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
  *
  * @param level can be SOL_SOCKET, SOL_IP, SOL_TCP, etc.
  * @param optname can be SO_{REUSE{PORT,ADDR},KEEPALIVE,etc.} etc.

libc/sock/shutdown-nt.c

@@ -16,12 +16,15 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/nt/thunk/msabi.h"
 #include "libc/nt/winsock.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/syscall_fd.internal.h"
 
+__msabi extern typeof(__sys_shutdown_nt) *const __imp_shutdown;
+
 textwindows int sys_shutdown_nt(struct Fd *fd, int how) {
-  if (__sys_shutdown_nt(fd->handle, how) != -1) {
+  if (__imp_shutdown(fd->handle, how) != -1) {
     return 0;
   } else {
     return __winsockerr();

tool/build/runitd.c

@@ -116,8 +116,9 @@ void OnInterrupt(int sig) {
 }
 
 void OnChildTerminated(int sig) {
-  int ws, pid;
+  int e, ws, pid;
   sigset_t ss, oldss;
+  e = errno;  // SIGCHLD can be called asynchronously
   sigfillset(&ss);
   sigdelset(&ss, SIGTERM);
   sigprocmask(SIG_BLOCK, &ss, &oldss);
@@ -140,6 +141,7 @@ void OnChildTerminated(int sig) {
     }
   }
   sigprocmask(SIG_SETMASK, &oldss, 0);
+  errno = e;
 }
 
 wontreturn void ShowUsage(FILE *f, int rc) {