using UpdateResource() with PInvoke

[tsahiasher]

hi,
i'm trying to use the Win32 API UpdateResource function to add a file
to an exe file, but somehow i'm getting a NullReferenceException when i
call the function. here is a piece of the code:

GCHandle gch = GCHandle.Alloc(fileBuffComp);
if (UpdateResource(hResource, "FILE", fileName, MakeLangId(0x09,
0x01),
/* */(IntPtr)gch, compFileLen) == false) {
throw new Win32Exception(Marshal.GetLastWin32Error());
}

where fileBuffComp is a byte array containing the file, after i read it
from disk (and compressed it with #ZipLib). the function is declared
like this:

[DllImport("kernel32.dll", SetLastError=true)]
static extern bool UpdateResource(IntPtr hUpdate, String lpType,
String lpName,
ushort wLanguage, IntPtr lpData, uint cbData);

any ideas?

[Mattias Sjögren]

> [DllImport("kernel32.dll", SetLastError=true)]

static extern bool UpdateResource(IntPtr hUpdate, String lpType,
String lpName,
ushort wLanguage, IntPtr lpData, uint cbData);

Change this to

.... ushort wLanguage, byte[] lpData, uint cbData);

and then pass in fileBuffComp directly, and get rid of the GCHandle.
Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[tsahiasher]

this solved the exception, but the file is not added to the file. are
you sure this is correct? the byte array is managed memory, which can
be moved around by the garbage collector, while the API is unmanaged
and normally expects a pointer to a buffer.

[tsahiasher]

i even tried this:

GCHandle gch = GCHandle.Alloc(fileBuffComp);
unsafe {
if (UpdateResource(hResource, "FILE", fileName,
MakeLangId(0x09, 0x01),
/* */((IntPtr)gch).ToPointer(), compFileLen) ==
false) {
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
with the declaration

[DllImport("kernel32.dll", SetLastError=true)]
static extern unsafe bool UpdateResource(IntPtr hUpdate, String
lpType, String lpName,
ushort wLanguage, void *lpData, uint cbData);

where the lpData is exactly what it is in the API, and it doesn't work.
i have a similar problem elswhere, where i try to remove a resource by
sending null to lpData, and it doesn't work either.

[Mick Doherty]

Don't know if it's exactly what you want, but here's how I add a file as a
Win32 Resource:
[DllImport("kernel32", CharSet=CharSet.Unicode)]
private static extern IntPtr BeginUpdateResource(String pFileName, bool
bDeleteExistingResources);

[DllImport("kernel32", CharSet=CharSet.Unicode, SetLastError=true)]
private static extern int UpdateResource(IntPtr hUpdate,
System.Text.StringBuilder lpType, System.Text.StringBuilder lpName, int16
wLanguage, Byte[] lpData, int cbData);

[DllImport("kernel32", SetLastError=true)]
private static extern int EndUpdateResource(IntPtr hUpdate, bool fDiscard);
private void someMethod()
{
IntPtr hResource = BeginUpdateResource(@"..\123.dll", false);

//I have only been able to get UpperCase strings to work.
//If the strings are not uppercase then the resources will
//be replaced instead of added.

//UpperCase String.
System.Text.StringBuilder resType =
new System.Text.StringBuilder("FILE");

//UpperCase String.
System.Text.StringBuilder resName =
new System.Text.StringBuilder("Test.txt".ToUpper());

System.IO.FileStream someFileStream =
new IO.FileStream("..\\Test.txt", IO.FileMode.Open);

System.IO.BinaryReader fileReader =
new System.IO.BinaryReader(someFileStream);

Byte[] someByteArray =
fileReader.ReadBytes((int)someFileStream.Length);

UpdateResource(hResource, resType, resName, 1033, someByteArray,
someByteArray.Length);

EndUpdateResource(hResource, false);

fileReader.Close();
someFileStream.Close();

}

--
Mick Doherty
http://dotnetrix.co.uk/nothing.html
<ts********@gmail.com> wrote in message
news:11**********************@g49g2000cwa.googlegr oups.com...

i even tried this:

GCHandle gch = GCHandle.Alloc(fileBuffComp);
unsafe {
if (UpdateResource(hResource, "FILE", fileName,
MakeLangId(0x09, 0x01),
/* */((IntPtr)gch).ToPointer(), compFileLen) ==
false) {
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
with the declaration

[DllImport("kernel32.dll", SetLastError=true)]
static extern unsafe bool UpdateResource(IntPtr hUpdate, String
lpType, String lpName,
ushort wLanguage, void *lpData, uint cbData);

where the lpData is exactly what it is in the API, and it doesn't work.
i have a similar problem elswhere, where i try to remove a resource by
sending null to lpData, and it doesn't work either.

[tsahiasher]

i noticed a funny thing: every time i try running UpdateResource() on
the executable, i get a file named RCXxxx.tmp at the same folder as the
executable, with "xxx" being a random alphanumeric 3-characters string,
about the same size as the executable. when i rename it to .exe, i find
that the changes i did (add a module, or remove a module by sending
null to lpData) are in this file instead of the original file. what's
that?

i use BinaryReader.Read(byte[], int, int) because i need the data to
start at a certain offset down the buffer, while writing other data at
the at the first 8 bytes (i don't just add a file. i add the file
zip-compressed, so i have to write the compressed and uncompressed size
into the start of the buffer, so i can uncompress it).

[tsahiasher]

i.e. when i use byte[] for lpData.

[tsahiasher]

i noticed a funny thing: every time i try running UpdateResource() on
the executable, i get a file named RCXxxx.tmp at the same folder as the
executable, with "xxx" being a random alphanumeric 3-characters string,
about the same size as the executable. when i rename it to .exe, i find
that the changes i did (add a module, or remove a module by sending
null to lpData) are in this file instead of the original file. what's
that?

i use BinaryReader.Read(byte[], int, int) because i need the data to
start at a certain offset down the buffer, while writing other data at
the at the first 8 bytes (i don't just add a file. i add the file
zip-compressed, so i have to write the compressed and uncompressed size
into the start of the buffer, so i can uncompress it).

[tsahiasher]

i.e. when i use byte[] for lpData.

[tsahiasher]

well, i fixed the RCXxxx.tmp thing - it was because the .exe was locked
with LoadLibrary() from another method and wasn't released
(FreeLibrary()). i would expect EndUpdateResource to return false in
this case, not create a tmp file :/

i will also try using the GCHandle.Alloc() method, it looks more
correct to me.

[tsahiasher]

well, i fixed the RCXxxx.tmp thing - it was because the .exe was locked
with LoadLibrary() from another method and wasn't released
(FreeLibrary()). i would expect EndUpdateResource to return false in
this case, not create a tmp file :/

i will also try using the GCHandle.Alloc() method, it looks more
correct to me.