CreateProcessA fails for some programs

Question

Found the below snippet here on SO: https://stackoverflow.com/a/35658917/9265719.

It executes a command without creating a window. CreateProcessA() returns TRUE for cmd.exe but for any program in C:\Program Files(x86)\Windows Kits\10\Debuggers\x64\ it returns FALSE and GetLastError() returns 2 (ERROR_PATH_NOT_FOUND).

Why is it failing to create a process for programs in this directory?

#include <iostream>
#include <windows.h>
//
// Execute a command and get the results. (Only standard output)
//
std::string ExecCmd(
    char cmd[]             // [in] command to execute
)
{
    std::string strResult;
    HANDLE hPipeRead, hPipeWrite;

    SECURITY_ATTRIBUTES saAttr = { sizeof(SECURITY_ATTRIBUTES) };
    saAttr.bInheritHandle = TRUE; // Pipe handles are inherited by child process.
    saAttr.lpSecurityDescriptor = NULL;

    // Create a pipe to get results from child's stdout.
    if (!CreatePipe(&hPipeRead, &hPipeWrite, &saAttr, 0))
        return strResult;

    STARTUPINFOA si = { sizeof(STARTUPINFOA) };
    si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;
    si.hStdOutput = hPipeWrite;
    si.hStdError = hPipeWrite;
    si.wShowWindow = SW_HIDE; // Prevents cmd window from flashing.
                              // Requires STARTF_USESHOWWINDOW in dwFlags.

    PROCESS_INFORMATION pi = { 0 };

    BOOL fSuccess = ::CreateProcessA(NULL, cmd, NULL, NULL, TRUE,
        CREATE_NO_WINDOW, NULL, NULL, &si, &pi);
    if (!fSuccess)
    {
        DWORD dw = GetLastError();
        CloseHandle(hPipeWrite);
        CloseHandle(hPipeRead);
        return strResult;
    }

    bool bProcessEnded = false;
    for (; !bProcessEnded;)
    {
        // Give some timeslice (50 ms), so we won't waste 100% CPU.
        bProcessEnded = WaitForSingleObject(pi.hProcess, 50) == WAIT_OBJECT_0;

        // Even if process exited - we continue reading, if
        // there is some data available over pipe.
        for (;;)
        {
            char buf[1024];
            DWORD dwRead = 0;
            DWORD dwAvail = 0;

            if (!::PeekNamedPipe(hPipeRead, NULL, 0, NULL, &dwAvail, NULL))
                break;

            if (!dwAvail) // No data available, return
                break;

            if (!::ReadFile(hPipeRead, buf, min(sizeof(buf) - 1, dwAvail), &dwRead, NULL) || !dwRead)
                // Error, the child process might ended
                break;

            buf[dwRead] = 0;
            strResult += buf;
        }
    } //for

    CloseHandle(hPipeWrite);
    CloseHandle(hPipeRead);
    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
    return strResult;
} //ExecCmd

int main()
{
    //char cmd[1000] = R"("C:\WINDOWS\system32\cmd.exe")"; 
    char cmd[1000] = R"("C:\Program Files(x86)\Windows Kits\10\Debuggers\x64\cdb.exe")";
    std::string op = ExecCmd(cmd);
    std::cout << op.c_str();
}

usually was space between *Files* and *(x86)* - so *Program Files (x86)* but not *Program Files(x86)* — RbMm, Mar 23 '21 at 10:21
Usually the error reported by the system is correct, as it is here. — David Heffernan, Mar 23 '21 at 10:29
If I ever get an error like this I always try pasting the same path into explorer as a quick sanity check, more often than not there is a typo that you just can't see and explorer rejects the path too — Alan Birtles, Mar 23 '21 at 11:13

score 0 · Accepted Answer · answered Mar 23 '21 at 10:22

0

You are missing a space in the path, between "Program Files" and "(x86)". Should be:

char cmd[1000] = R"("C:\Program Files (x86)\Windows Kits\10\Debuggers\x64\cdb.exe")";

answered Mar 23 '21 at 10:22

Ion Larrañaga

464
2
5

CreateProcessA fails for some programs

1 Answers1