/*

 * Helper program for killing lingering python[_d].exe processes before

 * building, thus attempting to avoid build failures due to files being

 * locked.

 */

#include <windows.h>

#include <wchar.h>

#include <tlhelp32.h>

#include <stdio.h>

#pragma comment(lib, "psapi")

#ifdef _DEBUG

#define PYTHON_EXE          (L"python_d.exe")

#define PYTHON_EXE_LEN      (12)

#define KILL_PYTHON_EXE     (L"kill_python_d.exe")

#define KILL_PYTHON_EXE_LEN (17)

#else

#define PYTHON_EXE          (L"python.exe")

#define PYTHON_EXE_LEN      (10)

#define KILL_PYTHON_EXE     (L"kill_python.exe")

#define KILL_PYTHON_EXE_LEN (15)

#endif

int

main(int argc, char **argv)

{

    HANDLE   hp, hsp, hsm; /* process, snapshot processes, snapshot modules */

    DWORD    dac, our_pid;

    size_t   len;

    wchar_t  path[MAX_PATH+1];

    MODULEENTRY32W  me;

    PROCESSENTRY32W pe;

    me.dwSize = sizeof(MODULEENTRY32W);

    pe.dwSize = sizeof(PROCESSENTRY32W);

    memset(path, 0, MAX_PATH+1);

    our_pid = GetCurrentProcessId();

    hsm = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, our_pid);

    if (hsm == INVALID_HANDLE_VALUE) {

        printf("CreateToolhelp32Snapshot[1] failed: %d\n", GetLastError());

        return 1;

    }

    if (!Module32FirstW(hsm, &me)) {

        printf("Module32FirstW[1] failed: %d\n", GetLastError());

        CloseHandle(hsm);

        return 1;

    }

    /*

     * Enumerate over the modules for the current process in order to find

     * kill_process[_d].exe, then take a note of the directory it lives in.

     */

    do {

        if (_wcsnicmp(me.szModule, KILL_PYTHON_EXE, KILL_PYTHON_EXE_LEN))

            continue;

        len = wcsnlen_s(me.szExePath, MAX_PATH) - KILL_PYTHON_EXE_LEN;

        wcsncpy_s(path, MAX_PATH+1, me.szExePath, len); 

        break;

    } while (Module32NextW(hsm, &me));

    CloseHandle(hsm);

    if (path == NULL) {

        printf("failed to discern directory of running process\n");

        return 1;

    }

    /*

     * Take a snapshot of system processes.  Enumerate over the snapshot,

     * looking for python processes.  When we find one, verify it lives

     * in the same directory we live in.  If it does, kill it.  If we're

     * unable to kill it, treat this as a fatal error and return 1.

     * 

     * The rationale behind this is that we're called at the start of the 

     * build process on the basis that we'll take care of killing any

     * running instances, such that the build won't encounter permission

     * denied errors during linking. If we can't kill one of the processes,

     * we can't provide this assurance, and the build shouldn't start.

     */

    hsp = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

    if (hsp == INVALID_HANDLE_VALUE) {

        printf("CreateToolhelp32Snapshot[2] failed: %d\n", GetLastError());

        return 1;

    }

    if (!Process32FirstW(hsp, &pe)) {

        printf("Process32FirstW failed: %d\n", GetLastError());

        CloseHandle(hsp);

        return 1;

    }

    dac = PROCESS_QUERY_INFORMATION | PROCESS_VM_READ | PROCESS_TERMINATE;

    do {

        /*

         * XXX TODO: if we really wanted to be fancy, we could check the 

         * modules for all processes (not just the python[_d].exe ones)

         * and see if any of our DLLs are loaded (i.e. python30[_d].dll),

         * as that would also inhibit our ability to rebuild the solution.

         * Not worth loosing sleep over though; for now, a simple check 

         * for just the python executable should be sufficient.

         */

        if (_wcsnicmp(pe.szExeFile, PYTHON_EXE, PYTHON_EXE_LEN))

            /* This isn't a python process. */

            continue;

        /* It's a python process, so figure out which directory it's in... */

        hsm = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, pe.th32ProcessID);

        if (hsm == INVALID_HANDLE_VALUE)

            /* 

             * If our module snapshot fails (which will happen if we don't own

             * the process), just ignore it and continue.  (It seems different

             * versions of Windows return different values for GetLastError()

             * in this situation; it's easier to just ignore it and move on vs.

             * stopping the build for what could be a false positive.)

             */

             continue;

        if (!Module32FirstW(hsm, &me)) {

            printf("Module32FirstW[2] failed: %d\n", GetLastError());

            CloseHandle(hsp);

            CloseHandle(hsm);

            return 1;

        }

        do {

            if (_wcsnicmp(me.szModule, PYTHON_EXE, PYTHON_EXE_LEN))

                /* Wrong module, we're looking for python[_d].exe... */

                continue;

            if (_wcsnicmp(path, me.szExePath, len))

                /* Process doesn't live in our directory. */

                break;

            /* Python process residing in the right directory, kill it!  */

            hp = OpenProcess(dac, FALSE, pe.th32ProcessID);

            if (!hp) {

                printf("OpenProcess failed: %d\n", GetLastError());

                CloseHandle(hsp);

                CloseHandle(hsm);

                return 1;

            }

            if (!TerminateProcess(hp, 1)) {

                printf("TerminateProcess failed: %d\n", GetLastError());

                CloseHandle(hsp);

                CloseHandle(hsm);

                CloseHandle(hp);

                return 1;

            }

            CloseHandle(hp);

            break;

        } while (Module32NextW(hsm, &me));

        CloseHandle(hsm);

    } while (Process32NextW(hsp, &pe));

    CloseHandle(hsp);

    return 0;

}

/* vi: set ts=8 sw=4 sts=4 expandtab */