Auto updater WinApi

Hello!
I'm trying to write an auto updater for my exe file, but I have face a problem when I trigger the auto update I want to remove the old version of my program by running an uninstaller, and here is the problem I can't do that because I need the AdminRights, is there a way I trigger the UAC window to prompt the users permission? or maybe there is another way of bypassing the UAC (giving addition rights for the process)?
I use the CreateProcess function and it is vital to use it only, because I will need the handle of the created process. I tried to use the ShellExecute function it worked ok, everything run nicely but I could not get the handle for the process, the WaitForSingleObject function did not want to work with the ShellExecute, therefore I switched to CreateProcess, so In advance I need a smth like ShellExecute but with CreateProcess on board.
Thank you!

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I need a smth like ShellExecute... I will need the handle of the created process

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Have a look at ShellExecuteEx(). https://msdn.microsoft.com/en-us/lib...(v=vs.85).aspx. This uses a SHELLEXECUTEINFO structure which has as one of its members a handle to the newly created process.

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Originally Posted by 2kaud

Have a look at ShellExecuteEx(). https://msdn.microsoft.com/en-us/lib...(v=vs.85).aspx. This uses a SHELLEXECUTEINFO structure which has as one of its members a handle to the newly created process.

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Yes I have fount this function but the WaitForSingleObject function does not wait for the process to be finished which is not good.

Code:

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ShellExecuteEx(&ShellInfo);
WaitForSingleObject(ShellInfo.hInstApp, INFINITE);
CloseHandle(ShellInfo.hProcess);

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Code:

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WaitForSingleObject(ShellInfo.hInstApp, INFINITE);

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hInstApp is not a true HINSTANCE but is really a return code. Try

Code:

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WaitForSingleObject(ShellInfo.hProcess, INFINITE);

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Note that fMask member needs to include SEE_MASK_NOCLOSEPROCESS

Quote:

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Originally Posted by 2kaud

Code:

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WaitForSingleObject(ShellInfo.hInstApp, INFINITE);

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hInstApp is not a true HINSTANCE but is really a return code. Try

Code:

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WaitForSingleObject(ShellInfo.hProcess, INFINITE);

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Note that fMask member needs to include SEE_MASK_NOCLOSEPROCESS

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The problem is still present
The setup for ShellExecuteEx, and maybe this could be the issue, but from my main program I create an instance of the auto-updater with CreateProcess, and it does wait. I know that inside the auto-updater does not work because it calls uninstall and instanlty install exe, the WaitForSingleObject returns 0.

Code:

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SHELLEXECUTEINFO ShellInfo = { 0 };
ShellInfo.cbSize = sizeof(SHELLEXECUTEINFOA);
ShellInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
ShellInfo.hwnd = NULL;
ShellInfo.lpVerb = L"runas";
ShellInfo.lpFile = L"path_to_installer.exe";
ShellInfo.lpParameters = L"";
ShellInfo.lpDirectory = L"path_to_installer's_folder";
ShellInfo.nShow = SW_NORMAL;

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See
https://stackoverflow.com/questions/...execute-to-run
https://social.msdn.microsoft.com/Fo...orum=vcgeneral

I have seen the first link, and I just copy pasted the answer code, and it still does not work

This test program works as expected. The message is displayed once the supplied command (testsh.exe) has completed execution after the User Account Control message window appears.

Code:

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#include <Windows.h>
#include <Shellapi.h>
#include <iostream>

int main()
{
        SHELLEXECUTEINFO ShExecInfo = { 0 };
        ShExecInfo.cbSize = sizeof(SHELLEXECUTEINFO);
        ShExecInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
        ShExecInfo.hwnd = NULL;
        ShExecInfo.lpVerb = "runas";
        ShExecInfo.lpFile = "testsh.exe";
        ShExecInfo.lpParameters = "";
        ShExecInfo.lpDirectory = NULL;
        ShExecInfo.nShow = SW_SHOW;
        ShExecInfo.hInstApp = NULL;
        ShellExecuteEx(&ShExecInfo);
        WaitForSingleObject(ShExecInfo.hProcess, INFINITE);

        std::cout << "after wait" << std::endl;
}

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PS Tested on Windows 7

Quote:

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Originally Posted by 2kaud

This test program works as expected. The message is displayed once the supplied command (testsh.exe) has completed execution after the User Account Control message window appears.

Code:

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#include <Windows.h>
#include <Shellapi.h>
#include <iostream>

int main()
{
        SHELLEXECUTEINFO ShExecInfo = { 0 };
        ShExecInfo.cbSize = sizeof(SHELLEXECUTEINFO);
        ShExecInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
        ShExecInfo.hwnd = NULL;
        ShExecInfo.lpVerb = "runas";
        ShExecInfo.lpFile = "testsh.exe";
        ShExecInfo.lpParameters = "";
        ShExecInfo.lpDirectory = NULL;
        ShExecInfo.nShow = SW_SHOW;
        ShExecInfo.hInstApp = NULL;
        ShellExecuteEx(&ShExecInfo);
        WaitForSingleObject(ShExecInfo.hProcess, INFINITE);

        std::cout << "after wait" << std::endl;
}

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PS Tested on Windows 7

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I have just tested the code snippet on W7 and it works good, but on Windows 10 the WaitForSingleObject is ignored

Test code works OK for me on Windows 10 :confused:

Quote:

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Originally Posted by 2kaud

Test code works OK for me on Windows 10 :confused:

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That's really strange, don't really know what to do:confused:

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Originally Posted by mandruk1331

That's really strange, don't really know what to do:confused:

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What type of test program do you have? Is it a console app? A windows app?

For my test program of post #8, this is a console prog and so is my testsh.exe that it calls.

PS Also works as expected with my Windows 7 and Windows 10 when testsh.exe is a windows program.

Quote:

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Originally Posted by Arjay

What type of test program do you have? Is it a console app? A windows app?

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The project type is Win32Console

Quote:

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Originally Posted by 2kaud

For my test program of post #8, this is a console prog and so is my testsh.exe that it calls.

PS Also works as expected with my Windows 7 and Windows 10 when testsh.exe is a windows program.

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Ok, I now have an error after the WaitForSingleObject function, the GetLastError function returns 6 (ERROR_INVALID_HANDLE), but the process is creating, what can be the problem? if the handle was not good, then the process would not be created

After calling which function are you calling GetLastError()? Note that GetLastError() only returns a valid error code under the conditions documented by the proceeding function call. Just calling GetLastError() after any function call and without checking first whether the function succeeded or failed will not give a reliable value.

Quote:

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Originally Posted by 2kaud

After calling which function are you calling GetLastError()? Note that GetLastError() only returns a valid error code under the conditions documented by the proceeding function call. Just calling GetLastError() after any function call and without checking first whether the function succeeded or failed will not give a reliable value.

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I call GetLastError after the WaitForSingleObject. If the mask par. in shellexecuteinfo is MASK_NOCLOSEAPP don't remember the correct name, then the error is 0 but is it's SYNCHRONIZE then the GetLastError is 6.
Ok. Got it. By exploring more, I noticed that if the ShellExecuteEx is called on creating a console app then the WaitForSingleObject works ok, but when I call it on a GUI application then the WaitForSingleObject is being ignored.
In shellexecuteEx I'm setting the hwnd parameter it is not a NULL value.

Following a call to WaitForSingleObject(), GetLastError() is only valid when WaitForSingleObject() returns a value of WAIT_FAILED. For any other return value, calling GetLastError() is not supported and hence its return value shouldn't be used.

And what to do that the WaitForSingleObject works with console app and not with the GUI ones?

What program are you calling from ShellExecuteEx()? Does this program create other processes? WaitForSingleObject() works OK on my Windows 10 when waiting for the gui programs I've tried. :confused:

Quote:

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Originally Posted by 2kaud

What program are you calling from ShellExecuteEx()? Does this program create other processes? WaitForSingleObject() works OK on my Windows 10 when waiting for the gui programs I've tried. :confused:

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well the process creation is like this:
process A calls a console process the console calls a gui process(needs UAC), when process A calls a console then WaitForSingleObjects waits, but when the console part calls the GUI then it does not wait.

Quote:

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Originally Posted by 2kaud

What program are you calling from ShellExecuteEx()? Does this program create other processes? WaitForSingleObject() works OK on my Windows 10 when waiting for the gui programs I've tried. :confused:

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I'm running a NSIS uninstaller over the ShellExecuteEx and the console app does not wait for it to finish. But when I try to run a notepad by specifing the full path the the WaitForSingleObject function works ok.

So the issue is with the NSIS uninstaller. I wonder if NSIS spawns new process(s)? That would fit with what is happening. NSIS does some work, spawns a new process and then exits. The new process continues to run but as the original process has terminated, WaitForSingleObject() returns because the process it is waiting on has terminated.

Quote:

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Originally Posted by 2kaud

So the issue is with the NSIS uninstaller. I wonder if NSIS spawns new process(s)? That would fit with what is happening. NSIS does some work, spawns a new process and then exits. The new process continues to run but as the original process has terminated, WaitForSingleObject() returns because the process it is waiting on has terminated.

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So when I spawn NSIS process, it then spawns another one?
How I can bypass this?

Quote:

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Originally Posted by mandruk1331

So when I spawn NSIS process, it then spawns another one?
How I can bypass this?

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That could be one explanation. If it is, then you can't bypass it - as you can't change NSIS behaviour. If you could find out if there is another process involved then it should be possible to open a handle to this other process and then wait on that handle.