gnu/dist/gettext/gettext-tools/lib/w32spawn.h

   1 /* Auxiliary functions for the creation of subprocesses.  Native Woe32 API.
   2    Copyright (C) 2003 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2003.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 /* Get declarations of the Win32 API functions.  */
  20 #define WIN32_LEAN_AND_MEAN
  21 #include <windows.h>
  22
  23 /* Get _get_osfhandle() and _open_osfhandle().  */
  24 #include <io.h>
  25
  26 #include <stdbool.h>
  27 #include <errno.h>
  28
  29 #include "strpbrk.h"
  30 #include "xalloc.h"
  31
  32 /* Duplicates a file handle, making the copy uninheritable.  */
  33 static int
  34 dup_noinherit (int fd)
  35 {
  36   HANDLE curr_process = GetCurrentProcess ();
  37   HANDLE old_handle = (HANDLE) _get_osfhandle (fd);
  38   HANDLE new_handle;
  39   int nfd;
  40
  41   if (!DuplicateHandle (curr_process,               /* SourceProcessHandle */
  42                         old_handle,                 /* SourceHandle */
  43                         curr_process,               /* TargetProcessHandle */
  44                         (PHANDLE) &new_handle,      /* TargetHandle */
  45                         (DWORD) 0,                  /* DesiredAccess */
  46                         FALSE,                      /* InheritHandle */
  47                         DUPLICATE_SAME_ACCESS))     /* Options */
  48     error (EXIT_FAILURE, 0, _("DuplicateHandle failed with error code 0x%08x"),
  49            GetLastError ());
  50
  51   nfd = _open_osfhandle ((long) new_handle, O_BINARY);
  52   if (nfd < 0)
  53     error (EXIT_FAILURE, errno, _("_open_osfhandle failed"));
  54
  55   return nfd;
  56 }
  57
  58 /* Prepares an argument vector before calling spawn().
  59    Note that spawn() does not by itself call the command interpreter
  60      (getenv ("COMSPEC") != NULL ? getenv ("COMSPEC") :
  61       ({ OSVERSIONINFO v; v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
  62          GetVersionEx(&v);
  63          v.dwPlatformId == VER_PLATFORM_WIN32_NT;
  64       }) ? "cmd.exe" : "command.com").
  65    Instead it simply concatenates the arguments, separated by ' ', and calls
  66    CreateProcess().  We must quote the arguments since Win32 CreateProcess()
  67    interprets characters like ' ', '\t', '\\', '"' (but not '<' and '>') in a
  68    special way:
  69    - Space and tab are interpreted as delimiters. They are not treated as
  70      delimiters if they are surrounded by double quotes: "...".
  71    - Unescaped double quotes are removed from the input. Their only effect is
  72      that within double quotes, space and tab are treated like normal
  73      characters.
  74    - Backslashes not followed by double quotes are not special.
  75    - But 2*n+1 backslashes followed by a double quote become
  76      n backslashes followed by a double quote (n >= 0):
  77        \" -> "
  78        \\\" -> \"
  79        \\\\\" -> \\"
  80  */
  81 #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"
  82 #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"
  83 static char **
  84 prepare_spawn (char **argv)
  85 {
  86   size_t argc;
  87   char **new_argv;
  88   size_t i;
  89
  90   /* Count number of arguments.  */
  91   for (argc = 0; argv[argc] != NULL; argc++)
  92     ;
  93
  94   /* Allocate new argument vector.  */
  95   new_argv = (char **) xmalloc ((argc + 1) * sizeof (char *));
  96
  97   /* Put quoted arguments into the new argument vector.  */
  98   for (i = 0; i < argc; i++)
  99     {
 100       const char *string = argv[i];
 101
 102       if (string[0] == '\0')
 103         new_argv[i] = xstrdup ("\"\"");
 104       else if (strpbrk (string, SHELL_SPECIAL_CHARS) != NULL)
 105         {
 106           bool quote_around = (strpbrk (string, SHELL_SPACE_CHARS) != NULL);
 107           size_t length;
 108           unsigned int backslashes;
 109           const char *s;
 110           char *quoted_string;
 111           char *p;
 112
 113           length = 0;
 114           backslashes = 0;
 115           if (quote_around)
 116             length++;
 117           for (s = string; *s != '\0'; s++)
 118             {
 119               char c = *s;
 120               if (c == '"')
 121                 length += backslashes + 1;
 122               length++;
 123               if (c == '\\')
 124                 backslashes++;
 125               else
 126                 backslashes = 0;
 127             }
 128           if (quote_around)
 129             length += backslashes + 1;
 130
 131           quoted_string = (char *) xmalloc (length + 1);
 132
 133           p = quoted_string;
 134           backslashes = 0;
 135           if (quote_around)
 136             *p++ = '"';
 137           for (s = string; *s != '\0'; s++)
 138             {
 139               char c = *s;
 140               if (c == '"')
 141                 {
 142                   unsigned int j;
 143                   for (j = backslashes + 1; j > 0; j--)
 144                     *p++ = '\\';
 145                 }
 146               *p++ = c;
 147               if (c == '\\')
 148                 backslashes++;
 149               else
 150                 backslashes = 0;
 151             }
 152           if (quote_around)
 153             {
 154               unsigned int j;
 155               for (j = backslashes; j > 0; j--)
 156                 *p++ = '\\';
 157               *p++ = '"';
 158             }
 159           *p = '\0';
 160
 161           new_argv[i] = quoted_string;
 162         }
 163       else
 164         new_argv[i] = (char *) string;
 165     }
 166   new_argv[argc] = NULL;
 167
 168   return new_argv;
 169 }