newlib/winsup/cygwin/shortcut.c

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/* shortcut.c: Read shortcuts. This part of the code must be in C because
the C++ interface to COM doesn't work without -fvtable-thunk
which is too dangerous to use.
Copyright 2001 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
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#define WIN32_LEAN_AND_MEAN
#include <shlobj.h>
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#include "winsup.h"
#include <ctype.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <errno.h>
#include "shortcut.h"
/* TODO:
Currently duplicated from path.h. Later rearrangement of path.h
to allow including from plain C would be better. */
/* This is needed to avoid including path.h which is a pure C++ header. */
#define PATH_SYMLINK MOUNT_SYMLINK
#define PATH_EXEC MOUNT_EXEC
#define PATH_CYGWIN_EXEC MOUNT_CYGWIN_EXEC
#define PATH_ALL_EXEC (PATH_CYGWIN_EXEC | PATH_EXEC)
/* TODO: Ditto. */
static BOOL
has_exec_chars (const char *buf, int len)
{
return len >= 2 &&
((buf[0] == '#' && buf[1] == '!') ||
(buf[0] == ':' && buf[1] == '\n') ||
(buf[0] == 'M' && buf[1] == 'Z'));
}
char shortcut_header[SHORTCUT_HDR_SIZE];
BOOL shortcut_initalized = FALSE;
void
create_shortcut_header (void)
{
if (!shortcut_initalized)
{
shortcut_header[0] = 'L';
shortcut_header[4] = '\001';
shortcut_header[5] = '\024';
shortcut_header[6] = '\002';
shortcut_header[12] = '\300';
shortcut_header[19] = 'F';
shortcut_header[20] = '\f';
shortcut_header[60] = '\001';
shortcut_initalized = TRUE;
}
}
static BOOL
cmp_shortcut_header (const char *file_header)
{
create_shortcut_header ();
return memcmp (shortcut_header, file_header, SHORTCUT_HDR_SIZE);
}
int
check_shortcut (const char *path, DWORD fileattr, HANDLE h,
char *contents, int *error, unsigned *pflags)
{
HRESULT hres;
IShellLink *psl = NULL;
IPersistFile *ppf = NULL;
WCHAR wc_path[MAX_PATH];
char full_path[MAX_PATH];
char file_header[SHORTCUT_HDR_SIZE];
WIN32_FIND_DATA wfd;
DWORD len = 0;
int res = 0;
DWORD got = 0;
/* Initialize COM library. */
CoInitialize (NULL);
/* Get a pointer to the IShellLink interface. */
hres = CoCreateInstance (&CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER,
&IID_IShellLink, (void **)&psl);
if (FAILED (hres))
goto close_it;
/* Get a pointer to the IPersistFile interface. */
hres = psl->lpVtbl->QueryInterface (psl, &IID_IPersistFile, (void **)&ppf);
if (FAILED (hres))
goto close_it;
/* Load the shortcut. */
MultiByteToWideChar(CP_ACP, 0, path, -1, wc_path, MAX_PATH);
hres = ppf->lpVtbl->Load (ppf, wc_path, STGM_READ);
if (FAILED (hres))
goto close_it;
/* Read the files header information. This is used to check for a
Cygwin or U/WIN shortcut or later to check for executable files. */
if (!ReadFile (h, file_header, SHORTCUT_HDR_SIZE, &got, 0))
{
*error = EIO;
goto close_it;
}
/* Try the description (containing a POSIX path) first. */
if (fileattr & FILE_ATTRIBUTE_READONLY)
{
/* Check header if the shortcut is really created by Cygwin or U/WIN. */
if (got == SHORTCUT_HDR_SIZE && !cmp_shortcut_header (file_header))
{
hres = psl->lpVtbl->GetDescription (psl, contents, MAX_PATH);
if (FAILED (hres))
goto file_not_symlink;
len = strlen (contents);
}
}
/* No description or not R/O: Check the "official" path. */
if (len == 0)
{
/* Convert to full path (easy way) */
if ((path[0] == '\\' && path[1] == '\\')
|| (_toupper (path[0]) >= 'A' && _toupper (path[0]) <= 'Z'
&& path[1] == ':'))
len = 0;
else
{
len = GetCurrentDirectory (MAX_PATH, full_path);
if (path[0] == '\\')
len = 2;
else if (full_path[len - 1] != '\\')
strcpy (full_path + len++, "\\");
}
strcpy (full_path + len, path);
/* Set relative path inside of IShellLink interface. */
hres = psl->lpVtbl->SetRelativePath (psl, full_path, 0);
if (FAILED (hres))
goto file_not_symlink;
/* Get the path to the shortcut target. */
hres = psl->lpVtbl->GetPath (psl, contents, MAX_PATH, &wfd, 0);
if (FAILED(hres))
goto file_not_symlink;
}
res = strlen (contents);
if (res) /* It's a symlink. */
*pflags = PATH_SYMLINK;
goto close_it;
file_not_symlink:
/* Not a symlink, see if executable. */
if (!(*pflags & PATH_ALL_EXEC) && has_exec_chars (file_header, got))
*pflags |= PATH_EXEC;
close_it:
/* Release the pointer to IPersistFile. */
if (ppf)
ppf->lpVtbl->Release(ppf);
/* Release the pointer to IShellLink. */
if (psl)
psl->lpVtbl->Release(psl);
/* Uninitialize COM library. */
CoUninitialize ();
CloseHandle (h);
return res;
}