Make improvements for Actually Portable Emacs

- Get SIGWINCH working again on the New Technology
- Correctly handle O_NOFOLLOW in open() on Windows
- Implement synthetic umask() functionality on Windows
- Do a better job managing file execute access on Windows
- Fill in `st_uid` and `st_gid` with username hash on Windows
- Munge UNICODE control pictures into control codes on Windows
- Do a better job ensuring Windows console settings are restored
- Introduce KPRINTF_LOG environment variable to log kprintf to a file

libc/calls/read-nt.c

@@ -26,9 +26,12 @@
 #include "libc/calls/syscall_support-nt.internal.h"
 #include "libc/calls/wincrash.internal.h"
 #include "libc/errno.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/intrin/nomultics.internal.h"
 #include "libc/intrin/strace.internal.h"
+#include "libc/intrin/weaken.h"
 #include "libc/macros.internal.h"
+#include "libc/nt/console.h"
 #include "libc/nt/enum/filetype.h"
 #include "libc/nt/enum/wait.h"
 #include "libc/nt/errors.h"
@@ -48,83 +51,12 @@
 
 #ifdef __x86_64__
 
-enum Action {
-  DO_NOTHING,
-  DO_RESTART,
-  DO_EINTR,
-};
-
 static textwindows void sys_read_nt_abort(int64_t handle,
                                           struct NtOverlapped *overlapped) {
   unassert(CancelIoEx(handle, overlapped) ||
            GetLastError() == kNtErrorNotFound);
 }
 
-static textwindows int MungeTerminalInput(char *p, uint32_t *n) {
-  size_t i, j;
-  if (!(__ttymagic & kFdTtyNoCr2Nl)) {
-    for (i = 0; i < *n; ++i) {
-      if (p[i] == '\r') {
-        p[i] = '\n';
-      }
-    }
-  }
-  if (!(__ttymagic & kFdTtyNoIsigs)) {
-    bool delivered = false;
-    bool got_vintr = false;
-    bool got_vquit = false;
-    for (j = i = 0; i < *n; ++i) {
-      if (__vintr != _POSIX_VDISABLE && p[i] == __vintr) {
-        got_vintr = true;
-      } else if (__vquit != _POSIX_VDISABLE && p[i] == __vquit) {
-        got_vquit = true;
-      } else {
-        p[j++] = p[i];
-      }
-    }
-    if (got_vintr) {
-      delivered |= __sig_handle(0, SIGINT, SI_KERNEL, 0);
-    }
-    if (got_vquit) {
-      delivered |= __sig_handle(0, SIGQUIT, SI_KERNEL, 0);
-    }
-    if (*n && !j) {
-      if (delivered) {
-        return DO_EINTR;
-      } else {
-        return DO_RESTART;
-      }
-    }
-    *n = j;
-  }
-  return DO_NOTHING;
-}
-
-// Manual CMD.EXE echoing for when !ICANON && ECHO is the case.
-static textwindows void EchoTerminalInput(struct Fd *fd, char *p, size_t n) {
-  int64_t hOutput;
-  if (fd->kind == kFdConsole) {
-    hOutput = fd->extra;
-  } else {
-    hOutput = g_fds.p[1].handle;
-  }
-  if (__ttymagic & kFdTtyEchoRaw) {
-    WriteFile(hOutput, p, n, 0, 0);
-  } else {
-    size_t i;
-    for (i = 0; i < n; ++i) {
-      if (isascii(p[i]) && iscntrl(p[i]) && p[i] != '\n' && p[i] != '\t') {
-        char ctl[2];
-        ctl[0] = '^';
-        ctl[1] = p[i] ^ 0100;
-        WriteFile(hOutput, ctl, 2, 0, 0);
-      } else {
-        WriteFile(hOutput, p + i, 1, 0, 0);
-      }
-    }
-  }
-}
-
 static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
                                             size_t size, int64_t offset) {
 
@@ -133,11 +65,38 @@ static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
   uint32_t got;
   int filetype;
   int64_t handle;
+  uint32_t remain;
+  uint32_t conmode;
+  char *targetdata;
+  uint32_t targetsize;
+  bool is_console_input;
   int abort_errno = EAGAIN;
 StartOver:
   size = MIN(size, 0x7ffff000);
   handle = __resolve_stdin_handle(fd->handle);
   filetype = GetFileType(handle);
+  is_console_input = g_fds.stdin.handle ? fd->handle == g_fds.stdin.handle
+                                        : fd->handle == g_fds.p[0].handle;
+
+  // the caller might be reading a single byte at a time. but we need to
+  // be able to munge three bytes into just 1 e.g. "\342\220\200" → "\0"
+  if (size && fd->buflen) {
+  ReturnDataFromBuffer:
+    got = MIN(size, fd->buflen);
+    remain = fd->buflen - got;
+    if (got) memcpy(data, fd->buf, got);
+    if (remain) memmove(fd->buf, fd->buf + got, remain);
+    fd->buflen = remain;
+    return got;
+  }
+  if (is_console_input && size && size < 3 && (__ttymagic & kFdTtyMunging)) {
+    targetdata = fd->buf;
+    targetsize = sizeof(fd->buf);
+  } else {
+    targetdata = data;
+    targetsize = size;
+  }
+
   if (filetype == kNtFileTypeChar || filetype == kNtFileTypePipe) {
     struct NtOverlapped overlap = {0};
     if (offset != -1) {
@@ -147,7 +106,7 @@ StartOver:
     if ((overlap.hEvent = CreateEvent(0, 0, 0, 0))) {
       // the win32 manual says it's important to *not* put &got here
       // since for overlapped i/o, we always use GetOverlappedResult
-      ok = ReadFile(handle, data, size, 0, &overlap);
+      ok = ReadFile(handle, targetdata, targetsize, 0, &overlap);
       if (!ok && GetLastError() == kNtErrorIoPending) {
         // the i/o operation is in flight; blocking is unavoidable
         // if we're in a non-blocking mode, then immediately abort
@@ -155,7 +114,7 @@ StartOver:
         // otherwise wait for i/o periodically checking interrupts
         if (fd->flags & O_NONBLOCK) {
           sys_read_nt_abort(handle, &overlap);
-        } else if (_check_interrupts(kSigOpRestartable, g_fds.p)) {
+        } else if (_check_interrupts(kSigOpRestartable)) {
         Interrupted:
           abort_errno = errno;
           sys_read_nt_abort(handle, &overlap);
@@ -164,7 +123,7 @@ StartOver:
             uint32_t i;
             i = WaitForSingleObject(overlap.hEvent, __SIG_POLLING_INTERVAL_MS);
             if (i == kNtWaitTimeout) {
-              if (_check_interrupts(kSigOpRestartable, g_fds.p)) {
+              if (_check_interrupts(kSigOpRestartable)) {
                 goto Interrupted;
               }
             } else {
@@ -186,7 +145,7 @@ StartOver:
     }
   } else if (offset == -1) {
     // perform simple blocking file read
-    ok = ReadFile(handle, data, size, &got, 0);
+    ok = ReadFile(handle, targetdata, targetsize, &got, 0);
   } else {
     // perform pread()-style file read at particular file offset
     int64_t position;
@@ -196,17 +155,17 @@ StartOver:
     }
     struct NtOverlapped overlap = {0};
     overlap.Pointer = (void *)(uintptr_t)offset;
-    ok = ReadFile(handle, data, size, 0, &overlap);
+    ok = ReadFile(handle, targetdata, targetsize, 0, &overlap);
     if (!ok && GetLastError() == kNtErrorIoPending) ok = true;
     if (ok) ok = GetOverlappedResult(handle, &overlap, &got, true);
     // restore file pointer which windows clobbers, even on error
     unassert(SetFilePointerEx(handle, position, 0, SEEK_SET));
   }
+
   if (ok) {
-    if (g_fds.stdin.handle ? fd->handle == g_fds.stdin.handle
-                           : fd->handle == g_fds.p[0].handle) {
+    if (is_console_input) {
       if (__ttymagic & kFdTtyMunging) {
-        switch (MungeTerminalInput(data, &got)) {
+        switch (_weaken(__munge_terminal_input)(targetdata, &got)) {
           case DO_NOTHING:
             break;
           case DO_RESTART:
@@ -218,9 +177,13 @@ StartOver:
         }
       }
       if (__ttymagic & kFdTtyEchoing) {
-        EchoTerminalInput(fd, data, got);
+        _weaken(__echo_terminal_input)(fd, targetdata, got);
       }
     }
+    if (targetdata != data) {
+      fd->buflen = got;
+      goto ReturnDataFromBuffer;
+    }
     return got;
   }
 
@@ -245,7 +208,7 @@ textwindows ssize_t sys_read_nt(struct Fd *fd, const struct iovec *iov,
   uint32_t size;
   size_t i, total;
   if (opt_offset < -1) return einval();
-  if (_check_interrupts(kSigOpRestartable, fd)) return -1;
+  if (_check_interrupts(kSigOpRestartable)) return -1;
   while (iovlen && !iov[0].iov_len) iov++, iovlen--;
   if (iovlen) {
     for (total = i = 0; i < iovlen; ++i) {