1 files changed, 233 insertions, 0 deletions
diff --git a/lib/w32spawn.h b/lib/w32spawn.h
new file mode 100644
index 0000000..3f675eb
--- /dev/null
+++ b/lib/w32spawn.h
@@ -0,0 +1,233 @@
+/* Auxiliary functions for the creation of subprocesses.  Native Windows API.
+   Copyright (C) 2001, 2003-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2003.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef __KLIBC__
+/* Get declarations of the native Windows API functions.  */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
+/* Get _open_osfhandle().  */
+#include <io.h>
+
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+/* Get _get_osfhandle().  */
+# if GNULIB_MSVC_NOTHROW
+#  include "msvc-nothrow.h"
+# else
+#  include <io.h>
+# endif
+
+#include "cloexec.h"
+#include "xalloc.h"
+
+/* Duplicates a file handle, making the copy uninheritable.
+   Returns -1 for a file handle that is equivalent to closed.  */
+static int
+dup_noinherit (int fd)
+{
+  fd = dup_cloexec (fd);
+  if (fd < 0 && errno == EMFILE)
+    error (EXIT_FAILURE, errno, _("_open_osfhandle failed"));
+
+  return fd;
+}
+
+/* Returns a file descriptor equivalent to FD, except that the resulting file
+   descriptor is none of STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO.
+   FD must be open and non-inheritable.  The result will be non-inheritable as
+   well.
+   If FD < 0, FD itself is returned.  */
+static int
+fd_safer_noinherit (int fd)
+{
+  if (STDIN_FILENO <= fd && fd <= STDERR_FILENO)
+    {
+      /* The recursion depth is at most 3.  */
+      int nfd = fd_safer_noinherit (dup_noinherit (fd));
+      int saved_errno = errno;
+      close (fd);
+      errno = saved_errno;
+      return nfd;
+    }
+  return fd;
+}
+
+/* Duplicates a file handle, making the copy uninheritable and ensuring the
+   result is none of STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO.
+   Returns -1 for a file handle that is equivalent to closed.  */
+static int
+dup_safer_noinherit (int fd)
+{
+  return fd_safer_noinherit (dup_noinherit (fd));
+}
+
+/* Undoes the effect of TEMPFD = dup_safer_noinherit (ORIGFD);  */
+static void
+undup_safer_noinherit (int tempfd, int origfd)
+{
+  if (tempfd >= 0)
+    {
+      if (dup2 (tempfd, origfd) < 0)
+        error (EXIT_FAILURE, errno, _("cannot restore fd %d: dup2 failed"),
+               origfd);
+      close (tempfd);
+    }
+  else
+    {
+      /* origfd was closed or open to no handle at all.  Set it to a closed
+         state.  This is (nearly) equivalent to the original state.  */
+      close (origfd);
+    }
+}
+
+/* Prepares an argument vector before calling spawn().
+   Note that spawn() does not by itself call the command interpreter
+     (getenv ("COMSPEC") != NULL ? getenv ("COMSPEC") :
+      ({ OSVERSIONINFO v; v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+         GetVersionEx(&v);
+         v.dwPlatformId == VER_PLATFORM_WIN32_NT;
+      }) ? "cmd.exe" : "command.com").
+   Instead it simply concatenates the arguments, separated by ' ', and calls
+   CreateProcess().  We must quote the arguments since Windows CreateProcess()
+   interprets characters like ' ', '\t', '\\', '"' (but not '<' and '>') in a
+   special way:
+   - Space and tab are interpreted as delimiters. They are not treated as
+     delimiters if they are surrounded by double quotes: "...".
+   - Unescaped double quotes are removed from the input. Their only effect is
+     that within double quotes, space and tab are treated like normal
+     characters.
+   - Backslashes not followed by double quotes are not special.
+   - But 2*n+1 backslashes followed by a double quote become
+     n backslashes followed by a double quote (n >= 0):
+       \" -> "
+       \\\" -> \"
+       \\\\\" -> \\"
+   - '*', '?' characters may get expanded through wildcard expansion in the
+     callee: By default, in the callee, the initialization code before main()
+     takes the result of GetCommandLine(), wildcard-expands it, and passes it
+     to main(). The exceptions to this rule are:
+       - programs that inspect GetCommandLine() and ignore argv,
+       - mingw programs that have a global variable 'int _CRT_glob = 0;',
+       - Cygwin programs, when invoked from a Cygwin program.
+ */
+#ifndef __KLIBC__
+# define SHELL_SPECIAL_CHARS "\"\\ \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037*?"
+# define SHELL_SPACE_CHARS " \001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037"
+#else
+# define SHELL_SPECIAL_CHARS ""
+# define SHELL_SPACE_CHARS ""
+#endif
+static char **
+prepare_spawn (char **argv)
+{
+  size_t argc;
+  char **new_argv;
+  size_t i;
+
+  /* Count number of arguments.  */
+  for (argc = 0; argv[argc] != NULL; argc++)
+    ;
+
+  /* Allocate new argument vector.  */
+  new_argv = XNMALLOC (1 + argc + 1, char *);
+
+  /* Add an element upfront that can be used when argv[0] turns out to be a
+     script, not a program.
+     On Unix, this would be "/bin/sh". On native Windows, "sh" is actually
+     "sh.exe".  We have to omit the directory part and rely on the search in
+     PATH, because the mingw "mount points" are not visible inside Windows
+     CreateProcess().  */
+  *new_argv++ = "sh.exe";
+
+  /* Put quoted arguments into the new argument vector.  */
+  for (i = 0; i < argc; i++)
+    {
+      const char *string = argv[i];
+
+      if (string[0] == '\0')
+        new_argv[i] = xstrdup ("\"\"");
+      else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL)
+        {
+          bool quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL);
+          size_t length;
+          unsigned int backslashes;
+          const char *s;
+          char *quoted_string;
+          char *p;
+
+          length = 0;
+          backslashes = 0;
+          if (quote_around)
+            length++;
+          for (s = string; *s != '\0'; s++)
+            {
+              char c = *s;
+              if (c == '"')
+                length += backslashes + 1;
+              length++;
+              if (c == '\\')
+                backslashes++;
+              else
+                backslashes = 0;
+            }
+          if (quote_around)
+            length += backslashes + 1;
+
+          quoted_string = (char *) xmalloc (length + 1);
+
+          p = quoted_string;
+          backslashes = 0;
+          if (quote_around)
+            *p++ = '"';
+          for (s = string; *s != '\0'; s++)
+            {
+              char c = *s;
+              if (c == '"')
+                {
+                  unsigned int j;
+                  for (j = backslashes + 1; j > 0; j--)
+                    *p++ = '\\';
+                }
+              *p++ = c;
+              if (c == '\\')
+                backslashes++;
+              else
+                backslashes = 0;
+            }
+          if (quote_around)
+            {
+              unsigned int j;
+              for (j = backslashes; j > 0; j--)
+                *p++ = '\\';
+              *p++ = '"';
+            }
+          *p = '\0';
+
+          new_argv[i] = quoted_string;
+        }
+      else
+        new_argv[i] = (char *) string;
+    }
+  new_argv[argc] = NULL;
+
+  return new_argv;
+}