PCbuild/kill_python.c

   1 /*
   2  * Helper program for killing lingering python[_d].exe processes before
   3  * building, thus attempting to avoid build failures due to files being
   4  * locked.
   5  */
   6
   7 #include <windows.h>
   8 #include <wchar.h>
   9 #include <tlhelp32.h>
  10 #include <stdio.h>
  11
  12 #pragma comment(lib, "psapi")
  13
  14 #ifdef _DEBUG
  15 #define PYTHON_EXE          (L"python_d.exe")
  16 #define PYTHON_EXE_LEN      (12)
  17 #define KILL_PYTHON_EXE     (L"kill_python_d.exe")
  18 #define KILL_PYTHON_EXE_LEN (17)
  19 #else
  20 #define PYTHON_EXE          (L"python.exe")
  21 #define PYTHON_EXE_LEN      (10)
  22 #define KILL_PYTHON_EXE     (L"kill_python.exe")
  23 #define KILL_PYTHON_EXE_LEN (15)
  24 #endif
  25
  26 int
  27 main(int argc, char **argv)
  28 {
  29     HANDLE   hp, hsp, hsm; /* process, snapshot processes, snapshot modules */
  30     DWORD    dac, our_pid;
  31     size_t   len;
  32     wchar_t  path[MAX_PATH+1];
  33
  34     MODULEENTRY32W  me;
  35     PROCESSENTRY32W pe;
  36
  37     me.dwSize = sizeof(MODULEENTRY32W);
  38     pe.dwSize = sizeof(PROCESSENTRY32W);
  39
  40     memset(path, 0, MAX_PATH+1);
  41
  42     our_pid = GetCurrentProcessId();
  43
  44     hsm = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, our_pid);
  45     if (hsm == INVALID_HANDLE_VALUE) {
  46         printf("CreateToolhelp32Snapshot[1] failed: %d\n", GetLastError());
  47         return 1;
  48     }
  49
  50     if (!Module32FirstW(hsm, &me)) {
  51         printf("Module32FirstW[1] failed: %d\n", GetLastError());
  52         CloseHandle(hsm);
  53         return 1;
  54     }
  55
  56     /*
  57      * Enumerate over the modules for the current process in order to find
  58      * kill_process[_d].exe, then take a note of the directory it lives in.
  59      */
  60     do {
  61         if (_wcsnicmp(me.szModule, KILL_PYTHON_EXE, KILL_PYTHON_EXE_LEN))
  62             continue;
  63
  64         len = wcsnlen_s(me.szExePath, MAX_PATH) - KILL_PYTHON_EXE_LEN;
  65         wcsncpy_s(path, MAX_PATH+1, me.szExePath, len);
  66
  67         break;
  68
  69     } while (Module32NextW(hsm, &me));
  70
  71     CloseHandle(hsm);
  72
  73     if (path == NULL) {
  74         printf("failed to discern directory of running process\n");
  75         return 1;
  76     }
  77
  78     /*
  79      * Take a snapshot of system processes.  Enumerate over the snapshot,
  80      * looking for python processes.  When we find one, verify it lives
  81      * in the same directory we live in.  If it does, kill it.  If we're
  82      * unable to kill it, treat this as a fatal error and return 1.
  83      *
  84      * The rationale behind this is that we're called at the start of the
  85      * build process on the basis that we'll take care of killing any
  86      * running instances, such that the build won't encounter permission
  87      * denied errors during linking. If we can't kill one of the processes,
  88      * we can't provide this assurance, and the build shouldn't start.
  89      */
  90
  91     hsp = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
  92     if (hsp == INVALID_HANDLE_VALUE) {
  93         printf("CreateToolhelp32Snapshot[2] failed: %d\n", GetLastError());
  94         return 1;
  95     }
  96
  97     if (!Process32FirstW(hsp, &pe)) {
  98         printf("Process32FirstW failed: %d\n", GetLastError());
  99         CloseHandle(hsp);
 100         return 1;
 101     }
 102
 103     dac = PROCESS_QUERY_INFORMATION | PROCESS_VM_READ | PROCESS_TERMINATE;
 104     do {
 105
 106         /*
 107          * XXX TODO: if we really wanted to be fancy, we could check the
 108          * modules for all processes (not just the python[_d].exe ones)
 109          * and see if any of our DLLs are loaded (i.e. python31[_d].dll),
 110          * as that would also inhibit our ability to rebuild the solution.
 111          * Not worth loosing sleep over though; for now, a simple check
 112          * for just the python executable should be sufficient.
 113          */
 114
 115         if (_wcsnicmp(pe.szExeFile, PYTHON_EXE, PYTHON_EXE_LEN))
 116             /* This isn't a python process. */
 117             continue;
 118
 119         /* It's a python process, so figure out which directory it's in... */
 120         hsm = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, pe.th32ProcessID);
 121         if (hsm == INVALID_HANDLE_VALUE)
 122             /*
 123              * If our module snapshot fails (which will happen if we don't own
 124              * the process), just ignore it and continue.  (It seems different
 125              * versions of Windows return different values for GetLastError()
 126              * in this situation; it's easier to just ignore it and move on vs.
 127              * stopping the build for what could be a false positive.)
 128              */
 129              continue;
 130
 131         if (!Module32FirstW(hsm, &me)) {
 132             printf("Module32FirstW[2] failed: %d\n", GetLastError());
 133             CloseHandle(hsp);
 134             CloseHandle(hsm);
 135             return 1;
 136         }
 137
 138         do {
 139             if (_wcsnicmp(me.szModule, PYTHON_EXE, PYTHON_EXE_LEN))
 140                 /* Wrong module, we're looking for python[_d].exe... */
 141                 continue;
 142
 143             if (_wcsnicmp(path, me.szExePath, len))
 144                 /* Process doesn't live in our directory. */
 145                 break;
 146
 147             /* Python process residing in the right directory, kill it!  */
 148             hp = OpenProcess(dac, FALSE, pe.th32ProcessID);
 149             if (!hp) {
 150                 printf("OpenProcess failed: %d\n", GetLastError());
 151                 CloseHandle(hsp);
 152                 CloseHandle(hsm);
 153                 return 1;
 154             }
 155
 156             if (!TerminateProcess(hp, 1)) {
 157                 printf("TerminateProcess failed: %d\n", GetLastError());
 158                 CloseHandle(hsp);
 159                 CloseHandle(hsm);
 160                 CloseHandle(hp);
 161                 return 1;
 162             }
 163
 164             CloseHandle(hp);
 165             break;
 166
 167         } while (Module32NextW(hsm, &me));
 168
 169         CloseHandle(hsm);
 170
 171     } while (Process32NextW(hsp, &pe));
 172
 173     CloseHandle(hsp);
 174
 175     return 0;
 176 }
 177
 178 /* vi: set ts=8 sw=4 sts=4 expandtab */