Improve system call polyfills

- Polyfill open() w/ O_CLOEXEC on RHEL5
- Remove old workaround from rmdir() on the New Technology
- preadv() and pwritev() are now smarter about demodernization
- preadv() and pwritev() are now available on the New Technology

libc/calls/getcwd-xnu.c

@@ -31,7 +31,7 @@ char *sys_getcwd_xnu(char *res, size_t size) {
   int fd;
   struct stat st[2];
   char buf[XNU_MAXPATHLEN], *ret = NULL;
-  if ((fd = sys_openat(AT_FDCWD, ".", O_RDONLY | O_DIRECTORY)) != -1) {
+  if ((fd = sys_openat(AT_FDCWD, ".", O_RDONLY | O_DIRECTORY, 0)) != -1) {
     if (sys_fstat(fd, &st[0]) != -1) {
       if (st[0].st_dev && st[0].st_ino) {
         if (sys_fcntl(fd, XNU_F_GETPATH, buf) != -1) {

libc/calls/internal.h

@@ -108,6 +108,7 @@ i32 __sys_dup3(i32, i32, i32) hidden;
 i32 __sys_execve(const char *, char *const[], char *const[]) hidden;
 i32 __sys_fstat(i32, struct stat *) hidden;
 i32 __sys_fstatat(i32, const char *, struct stat *, i32) hidden;
+i32 __sys_openat(i32, const char *, i32, u32) hidden;
 i32 __sys_pipe2(i32[hasatleast 2], u32) hidden;
 i32 __sys_utimensat(i32, const char *, const struct timespec *, i32) hidden;
 i32 getdents(i32, char *, u32, i64 *) hidden;
@@ -153,7 +154,7 @@ i32 sys_mprotect(void *, u64, i32) hidden;
 i32 sys_msync(void *, u64, i32) hidden;
 i32 sys_munmap(void *, u64) hidden;
 i32 sys_nanosleep(const struct timespec *, struct timespec *) hidden;
-i32 sys_openat(i32, const char *, i32, ...) hidden;
+i32 sys_openat(i32, const char *, i32, u32) hidden;
 i32 sys_pause(void) hidden;
 i32 sys_pipe(i32[hasatleast 2]) hidden;
 i32 sys_pipe2(i32[hasatleast 2], u32) hidden;
@@ -218,6 +219,7 @@ void __sigenter_xnu(void *, i32, i32, struct __darwin_siginfo *,
 int gethostname_linux(char *, size_t) hidden;
 int gethostname_bsd(char *, size_t) hidden;
 int gethostname_nt(char *, size_t) hidden;
+size_t __iovec_size(const struct iovec *, size_t) hidden;
 
 /*───────────────────────────────────────────────────────────────────────────│─╗
 │ cosmopolitan § syscalls » windows nt » veneers                           ─╬─│┼

libc/calls/iovecsize.c

@@ -0,0 +1,27 @@
+/*-*- 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/calls/internal.h"
+
+size_t __iovec_size(const struct iovec *v, size_t n) {
+  size_t i, sum;
+  for (sum = i = 0; i < n; ++i) {
+    sum += v[i].iov_len;
+  }
+  return sum;
+}

libc/calls/openat-sysv.c

@@ -0,0 +1,44 @@
+/*-*- 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/calls/internal.h"
+#include "libc/errno.h"
+#include "libc/sysv/consts/f.h"
+#include "libc/sysv/consts/fd.h"
+#include "libc/sysv/consts/o.h"
+
+int sys_openat(int dirfd, const char *file, int flags, unsigned mode) {
+  int fd, err;
+  err = errno;
+  fd = __sys_openat(dirfd, file, flags, mode);
+
+  /*
+   * RHEL5 doesn't support O_CLOEXEC
+   * What on earth is it doing here?
+   * It returns -530!
+   */
+  if (IsLinux() && fd == -1 && errno > 255) {
+    errno = err;
+    fd = __sys_openat(dirfd, file, flags & ~O_CLOEXEC, mode);
+    if (fd != -1 && (flags & O_CLOEXEC)) {
+      sys_fcntl(fd, F_SETFD, FD_CLOEXEC);
+    }
+  }
+
+  return fd;
+}

libc/calls/preadv.c

@@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/bits/bits.h"
+#include "libc/bits/weaken.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/struct/iovec.h"
@@ -25,54 +26,84 @@
 #include "libc/macros.internal.h"
 #include "libc/sysv/consts/iov.h"
 #include "libc/sysv/errfuns.h"
+#include "libc/zipos/zipos.internal.h"
 
 #define __NR_preadv_linux 0x0127
 
 /**
- * Reads data from multiple buffers from file descriptor at offset.
+ * Reads with maximum generality.
  *
- * @param count is recommended to be 16 or fewer; if it exceeds IOV_MAX
- *     then the extra buffers are simply ignored
  * @return number of bytes actually read, or -1 w/ errno
  * @asyncsignalsafe
  * @vforksafe
  */
-ssize_t preadv(int fd, struct iovec *iovec, int count, int64_t off) {
+ssize_t preadv(int fd, struct iovec *iov, int iovlen, int64_t off) {
   static bool once, demodernize;
-  int olderr;
+  int i, err;
   ssize_t rc;
-  if (!count) return 0;
-  if ((count = MIN(count, IOV_MAX)) < 0) return einval();
+  size_t got, toto;
+
+  if (fd < 0) return einval();
+  if (iovlen < 0) return einval();
+  if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
+    return weaken(__zipos_read)(
+        (struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, off);
+  } else if (IsWindows()) {
+    if (fd < g_fds.n) {
+      return sys_read_nt(g_fds.p + fd, iov, iovlen, off);
+    } else {
+      return ebadf();
+    }
+  } else if (IsMetal()) {
+    return enosys();
+  }
 
   /*
    * NT, XNU, and 2007-era Linux don't support this system call.
    */
   if (!once) {
-    once = true;
-    if (IsModeDbg() || (IsLinux() && iovec->iov_len >= __NR_preadv_linux)) {
-      /*
-       * Read size is too large to detect older kernels safely without
-       * introducing nontrivial mechanics. We'll try again later.
-       */
-      once = false;
+    err = errno;
+    rc = sys_preadv(fd, iov, iovlen, off, off);
+    if (rc == -1 && errno == ENOSYS) {
+      errno = err;
+      once = true;
       demodernize = true;
-    } else {
-      olderr = errno;
-      rc = sys_preadv(fd, iovec, count, off, off);
-      if (rc == -1 && errno == ENOSYS) {
-        errno = olderr;
-        demodernize = true;
-      } else if (IsLinux() && rc == __NR_preadv_linux /*RHEL5:CVE-2010-3301*/) {
-        demodernize = true;
+    } else if (IsLinux() && rc == __NR_preadv_linux) {
+      if (__iovec_size(iov, iovlen) < __NR_preadv_linux) {
+        demodernize = true; /*RHEL5:CVE-2010-3301*/
+        once = true;
       } else {
         return rc;
       }
+    } else {
+      once = true;
+      return rc;
     }
   }
 
   if (!demodernize) {
-    return sys_preadv(fd, iovec, count, off, off);
-  } else {
-    return pread(fd, iovec[0].iov_base, iovec[0].iov_len, off);
+    return sys_preadv(fd, iov, iovlen, off, off);
   }
+
+  if (!iovlen) {
+    return sys_pread(fd, NULL, 0, off, off);
+  }
+
+  for (toto = i = 0; i < iovlen; ++i) {
+    rc = sys_pread(fd, iov[i].iov_base, iov[i].iov_len, off, off);
+    if (rc == -1) {
+      if (toto && (errno == EINTR || errno == EAGAIN)) {
+        return toto;
+      } else {
+        return -1;
+      }
+    }
+    got = rc;
+    toto += got;
+    if (got != iov[i].iov_len) {
+      break;
+    }
+  }
+
+  return toto;
 }

libc/calls/pwritev.c

@@ -16,6 +16,7 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/weaken.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/struct/iovec.h"
@@ -24,6 +25,7 @@
 #include "libc/macros.internal.h"
 #include "libc/sysv/consts/iov.h"
 #include "libc/sysv/errfuns.h"
+#include "libc/zipos/zipos.internal.h"
 
 #define __NR_pwritev_linux 0x0128
 
@@ -35,49 +37,77 @@
  * been committed. It can also happen if we need to polyfill this system
  * call using pwrite().
  *
- * @param count is recommended to be 16 or fewer; if it exceeds IOV_MAX
- *     then the extra buffers are simply ignored
  * @return number of bytes actually sent, or -1 w/ errno
  * @asyncsignalsafe
  * @vforksafe
  */
-ssize_t pwritev(int fd, const struct iovec *iovec, int count, int64_t off) {
+ssize_t pwritev(int fd, const struct iovec *iov, int iovlen, int64_t off) {
   static bool once, demodernize;
-  int olderr;
+  int i, err;
   ssize_t rc;
-  if (!count) return 0;
-  if ((count = MIN(count, IOV_MAX)) < 0) return einval();
+  size_t sent, toto;
+
+  if (fd < 0) return einval();
+  if (iovlen < 0) return einval();
+  if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
+    return weaken(__zipos_write)(
+        (struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, off);
+  } else if (IsWindows()) {
+    if (fd < g_fds.n) {
+      return sys_write_nt(g_fds.p + fd, iov, iovlen, off);
+    } else {
+      return ebadf();
+    }
+  } else if (IsMetal()) {
+    return enosys();
+  }
 
   /*
    * NT, XNU, and 2007-era Linux don't support this system call.
    */
   if (!once) {
-    once = true;
-    if (IsModeDbg() || (IsLinux() && iovec->iov_len >= __NR_pwritev_linux)) {
-      /*
-       * Write size is too large to detect older kernels safely without
-       * introducing nontrivial mechanics. We'll try again later.
-       */
-      once = false;
+    err = errno;
+    rc = sys_pwritev(fd, iov, iovlen, off, off);
+    if (rc == -1 && errno == ENOSYS) {
+      errno = err;
+      once = true;
       demodernize = true;
-    } else {
-      olderr = errno;
-      rc = sys_pwritev(fd, iovec, count, off, off);
-      if (rc == -1 && errno == ENOSYS) {
-        errno = olderr;
-        demodernize = true;
-      } else if (IsLinux() &&
-                 rc == __NR_pwritev_linux /*RHEL5:CVE-2010-3301*/) {
-        demodernize = true;
+    } else if (IsLinux() && rc == __NR_pwritev_linux) {
+      if (__iovec_size(iov, iovlen) < __NR_pwritev_linux) {
+        demodernize = true; /*RHEL5:CVE-2010-3301*/
+        once = true;
       } else {
         return rc;
       }
+    } else {
+      once = true;
+      return rc;
     }
   }
 
   if (!demodernize) {
-    return sys_pwritev(fd, iovec, count, off, off);
-  } else {
-    return pwrite(fd, iovec[0].iov_base, iovec[0].iov_len, off);
+    return sys_pwritev(fd, iov, iovlen, off, off);
   }
+
+  if (!iovlen) {
+    return sys_pwrite(fd, NULL, 0, off, off);
+  }
+
+  for (toto = i = 0; i < iovlen; ++i) {
+    rc = sys_pwrite(fd, iov[i].iov_base, iov[i].iov_len, off, off);
+    if (rc == -1) {
+      if (toto && (errno == EINTR || errno == EAGAIN)) {
+        return toto;
+      } else {
+        return -1;
+      }
+    }
+    sent = rc;
+    toto += sent;
+    if (sent != iov[i].iov_len) {
+      break;
+    }
+  }
+
+  return toto;
 }

libc/calls/unlinkat-nt.c

@@ -33,25 +33,11 @@ static textwindows int sys_unlink_nt(const char16_t *path) {
 }
 
 static textwindows int sys_rmdir_nt(const char16_t *path) {
-  int e, ms;
-  for (ms = 1;; ms *= 2) {
-    if (RemoveDirectory(path)) return 0;
-    /*
-     * Files can linger, for absolutely no reason.
-     * Possibly some Windows Defender bug on Win7.
-     * Sleep for up to one second w/ expo backoff.
-     * Alternative is use Microsoft internal APIs.
-     * Never could have imagined it'd be this bad.
-     */
-    if ((e = GetLastError()) == kNtErrorDirNotEmpty && ms <= 512) {
-      Sleep(ms);
-      continue;
-    } else {
-      break;
-    }
+  if (RemoveDirectory(path)) {
+    return 0;
+  } else {
+    return __winerr();
   }
-  errno = e;
-  return -1;
 }
 
 textwindows int sys_unlinkat_nt(int dirfd, const char *path, int flags) {

libc/calls/write-nt.c

@@ -25,14 +25,6 @@
 #include "libc/nt/struct/overlapped.h"
 #include "libc/sysv/errfuns.h"
 
-static textwindows size_t SumIovecLen(const struct iovec *v, size_t n) {
-  size_t i, sum;
-  for (sum = i = 0; i < n; ++i) {
-    sum += v[i].iov_len;
-  }
-  return sum;
-}
-
 textwindows ssize_t sys_write_nt(struct Fd *fd, const struct iovec *iov,
                                  size_t iovlen, ssize_t opt_offset) {
   size_t i, total;
@@ -52,7 +44,7 @@ textwindows ssize_t sys_write_nt(struct Fd *fd, const struct iovec *iov,
         return __winerr();
       }
     }
-    if (!total) assert(!SumIovecLen(iov, iovlen));
+    if (!total) assert(!__iovec_size(iov, iovlen));
     return total;
   } else {
     if (WriteFile(fd->handle, NULL, 0, &wrote,