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/* Auxiliary functions for the creation of subprocesses. Native Woe32 API.
Copyright (C) 2003, 2006, 2007 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 <http://www.gnu.org/licenses/>. */
/* Get declarations of the Win32 API functions. */
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
/* Get _get_osfhandle() and _open_osfhandle(). */
#include <io.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include "xalloc.h"
/* Duplicates a file handle, making the copy uninheritable. */
static int
dup_noinherit (int fd)
{
HANDLE curr_process = GetCurrentProcess ();
HANDLE old_handle = (HANDLE) _get_osfhandle (fd);
HANDLE new_handle;
int nfd;
if (!DuplicateHandle (curr_process, /* SourceProcessHandle */
old_handle, /* SourceHandle */
curr_process, /* TargetProcessHandle */
(PHANDLE) &new_handle, /* TargetHandle */
(DWORD) 0, /* DesiredAccess */
FALSE, /* InheritHandle */
DUPLICATE_SAME_ACCESS)) /* Options */
error (EXIT_FAILURE, 0, _("DuplicateHandle failed with error code 0x%08x"),
GetLastError ());
nfd = _open_osfhandle ((long) new_handle, O_BINARY);
if (nfd < 0)
error (EXIT_FAILURE, errno, _("_open_osfhandle failed"));
return nfd;
}
/* 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 Win32 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):
\" -> "
\\\" -> \"
\\\\\" -> \\"
*/
#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"
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 (argc + 1, char *);
/* 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;
}
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