Date: 2025-03-29T05:58:45+00:00

Actual source code: pythonsys.c

      1: #include <petsc/private/petscimpl.h>

      3: #if !defined(PETSC_PYTHON_EXE)
      4:   #define PETSC_PYTHON_EXE "python"
      5: #endif

      7: static PetscErrorCode PetscPythonFindExecutable(char pythonexe[], size_t len)
      8: {
      9:   PetscBool flag;

     11:   PetscFunctionBegin;
     12:   /* get the path for the Python interpreter executable */
     13:   PetscCall(PetscStrncpy(pythonexe, PETSC_PYTHON_EXE, len));
     14:   PetscCall(PetscOptionsGetString(NULL, NULL, "-python", pythonexe, len, &flag));
     15:   if (!flag || pythonexe[0] == 0) PetscCall(PetscStrncpy(pythonexe, PETSC_PYTHON_EXE, len));
     16:   PetscFunctionReturn(PETSC_SUCCESS);
     17: }

     19: /*
     20:     Python does not appear to have a universal way to indicate the location of Python dynamic library so try several possibilities
     21: */
     22: static PetscErrorCode PetscPythonFindLibraryName(const char pythonexe[], const char attempt[], char pythonlib[], size_t pl, PetscBool *found)
     23: {
     24:   char  command[2 * PETSC_MAX_PATH_LEN];
     25:   FILE *fp  = NULL;
     26:   char *eol = NULL;

     28:   PetscFunctionBegin;
     29:   /* call Python to find out the name of the Python dynamic library */
     30:   PetscCall(PetscStrncpy(command, pythonexe, sizeof(command)));
     31:   PetscCall(PetscStrlcat(command, " ", sizeof(command)));
     32:   PetscCall(PetscStrlcat(command, attempt, sizeof(command)));
     33: #if defined(PETSC_HAVE_POPEN)
     34:   PetscCall(PetscPOpen(PETSC_COMM_SELF, NULL, command, "r", &fp));
     35:   PetscCheck(fgets(pythonlib, (int)pl, fp), PETSC_COMM_SELF, PETSC_ERR_PLIB, "Python: bad output from executable: %s, running: %s", pythonexe, command);
     36:   PetscCall(PetscPClose(PETSC_COMM_SELF, fp));
     37: #else
     38:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: Aborted due to missing popen()");
     39: #endif
     40:   /* remove newlines */
     41:   PetscCall(PetscStrchr(pythonlib, '\n', &eol));
     42:   if (eol) eol[0] = 0;
     43:   PetscCall(PetscTestFile(pythonlib, 'r', found));
     44:   PetscFunctionReturn(PETSC_SUCCESS);
     45: }

     47: static PetscErrorCode PetscPythonFindLibrary(const char pythonexe[], char pythonlib[], size_t pl)
     48: {
     49:   // clang-format off
     50:   const char *const cmdlines[] = {"-c 'import os, sysconfig; print(os.path.join(sysconfig.get_config_var(\"LIBDIR\"),sysconfig.get_config_var(\"LDLIBRARY\")))'",
     51:                                   "-c 'import os, sysconfig; print(os.path.join(sysconfig.get_path(\"stdlib\"),os.path.pardir,\"libpython\"+sysconfig.get_python_version()+\".dylib\"))'",
     52:                                   "-c 'import os, sysconfig; print(os.path.join(sysconfig.get_path(\"stdlib\"),os.path.pardir,\"libpython\"+sysconfig.get_python_version()+\".so\"))'",
     53:                                   "-c 'import os, sysconfig; print(os.path.join(sysconfig.get_config_var(\"LIBPL\"),sysconfig.get_config_var(\"LDLIBRARY\")))'",
     54:                                   "-c 'import sysconfig; print(sysconfig.get_config_var(\"LIBPYTHON\"))'",
     55:                                   "-c 'import os, sysconfig; print(os.path.join(sysconfig.get_config_var(\"LIBDIR\"),\"libpython\"+sysconfig.get_python_version()+\".dylib\"))'",
     56:                                   "-c 'import os, sysconfig; print(os.path.join(sysconfig.get_config_var(\"LIBDIR\"),\"libpython\"+sysconfig.get_python_version()+\".so\"))'"};
     57:   // clang-format on

     59:   PetscBool found = PETSC_FALSE;

     61:   PetscFunctionBegin;
     62: #if defined(PETSC_PYTHON_LIB)
     63:   PetscCall(PetscStrncpy(pythonlib, PETSC_PYTHON_LIB, pl));
     64:   PetscFunctionReturn(PETSC_SUCCESS);
     65: #endif

     67:   for (size_t i = 0; i < PETSC_STATIC_ARRAY_LENGTH(cmdlines); i++) {
     68:     PetscCall(PetscInfo(NULL, "Looking for Python library with \"%s %s\"\n", pythonexe, cmdlines[i]));
     69:     PetscCall(PetscPythonFindLibraryName(pythonexe, cmdlines[i], pythonlib, pl, &found));
     70:     if (found) break;
     71:   }
     72:   PetscCall(PetscInfo(NULL, "Python library %s found %d\n", pythonlib, found));
     73:   PetscFunctionReturn(PETSC_SUCCESS);
     74: }

     76: typedef struct _Py_object_t PyObject; /* fake definition */

     78: static PyObject *Py_None = NULL;

     80: static const char *(*Py_GetVersion)(void);

     82: static int (*Py_IsInitialized)(void);
     83: static void (*Py_InitializeEx)(int);
     84: static void (*Py_Finalize)(void);

     86: static void (*PySys_SetArgv)(int, void *);
     87: static PyObject *(*PySys_GetObject)(const char *);
     88: static PyObject *(*PyObject_CallMethod)(PyObject *, const char *, const char *, ...);
     89: static PyObject *(*PyImport_ImportModule)(const char *);

     91: static void (*Py_IncRef)(PyObject *);
     92: static void (*Py_DecRef)(PyObject *);

     94: static void (*PyErr_Clear)(void);
     95: static PyObject *(*PyErr_Occurred)(void);
     96: static void (*PyErr_Fetch)(PyObject **, PyObject **, PyObject **);
     97: static void (*PyErr_NormalizeException)(PyObject **, PyObject **, PyObject **);
     98: static void (*PyErr_Display)(PyObject *, PyObject *, PyObject *);
     99: static void (*PyErr_Restore)(PyObject *, PyObject *, PyObject *);

    101: #define PetscDLPyLibOpen(libname)      PetscDLLibraryAppend(PETSC_COMM_SELF, &PetscDLLibrariesLoaded, libname)
    102: #define PetscDLPyLibSym(symbol, value) PetscDLLibrarySym(PETSC_COMM_SELF, &PetscDLLibrariesLoaded, NULL, symbol, (void **)value)
    103: #define PetscDLPyLibClose(comm) \
    104:   do { \
    105:   } while (0)

    107: static PetscErrorCode PetscPythonLoadLibrary(const char pythonlib[])
    108: {
    109:   PetscFunctionBegin;
    110:   /* open the Python dynamic library */
    111:   PetscCall(PetscDLPyLibOpen(pythonlib));
    112:   PetscCall(PetscInfo(NULL, "Python: loaded dynamic library %s\n", pythonlib));
    113:   /* look required symbols from the Python C-API */
    114:   PetscCall(PetscDLPyLibSym("_Py_NoneStruct", &Py_None));
    115:   PetscCall(PetscDLPyLibSym("Py_GetVersion", &Py_GetVersion));
    116:   PetscCall(PetscDLPyLibSym("Py_IsInitialized", &Py_IsInitialized));
    117:   PetscCall(PetscDLPyLibSym("Py_InitializeEx", &Py_InitializeEx));
    118:   PetscCall(PetscDLPyLibSym("Py_Finalize", &Py_Finalize));
    119:   PetscCall(PetscDLPyLibSym("PySys_GetObject", &PySys_GetObject));
    120:   PetscCall(PetscDLPyLibSym("PySys_SetArgv", &PySys_SetArgv));
    121:   PetscCall(PetscDLPyLibSym("PyObject_CallMethod", &PyObject_CallMethod));
    122:   PetscCall(PetscDLPyLibSym("PyImport_ImportModule", &PyImport_ImportModule));
    123:   PetscCall(PetscDLPyLibSym("Py_IncRef", &Py_IncRef));
    124:   PetscCall(PetscDLPyLibSym("Py_DecRef", &Py_DecRef));
    125:   PetscCall(PetscDLPyLibSym("PyErr_Clear", &PyErr_Clear));
    126:   PetscCall(PetscDLPyLibSym("PyErr_Occurred", &PyErr_Occurred));
    127:   PetscCall(PetscDLPyLibSym("PyErr_Fetch", &PyErr_Fetch));
    128:   PetscCall(PetscDLPyLibSym("PyErr_NormalizeException", &PyErr_NormalizeException));
    129:   PetscCall(PetscDLPyLibSym("PyErr_Display", &PyErr_Display));
    130:   PetscCall(PetscDLPyLibSym("PyErr_Restore", &PyErr_Restore));
    131:   /* XXX TODO: check that ALL symbols were there !!! */
    132:   PetscCheck(Py_None, PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: failed to load symbols from Python dynamic library %s", pythonlib);
    133:   PetscCheck(Py_GetVersion, PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: failed to load symbols from Python dynamic library %s", pythonlib);
    134:   PetscCheck(Py_IsInitialized, PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: failed to load symbols from Python dynamic library %s", pythonlib);
    135:   PetscCheck(Py_InitializeEx, PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: failed to load symbols from Python dynamic library %s", pythonlib);
    136:   PetscCheck(Py_Finalize, PETSC_COMM_SELF, PETSC_ERR_LIB, "Python: failed to load symbols from Python dynamic library %s", pythonlib);
    137:   PetscCall(PetscInfo(NULL, "Python: all required symbols loaded from Python dynamic library %s\n", pythonlib));
    138:   PetscFunctionReturn(PETSC_SUCCESS);
    139: }

    141: static char      PetscPythonExe[PETSC_MAX_PATH_LEN] = {0};
    142: static char      PetscPythonLib[PETSC_MAX_PATH_LEN] = {0};
    143: static PetscBool PetscBeganPython                   = PETSC_FALSE;

    145: /*@
    146:   PetscPythonFinalize - Finalize PETSc for use with Python.

    148:   Level: intermediate

    150: .seealso: `PetscPythonInitialize()`, `PetscPythonPrintError()`
    151: @*/
    152: PetscErrorCode PetscPythonFinalize(void)
    153: {
    154:   PetscFunctionBegin;
    155:   if (PetscBeganPython) {
    156:     if (Py_IsInitialized()) Py_Finalize();
    157:   }
    158:   PetscBeganPython = PETSC_FALSE;
    159:   PetscFunctionReturn(PETSC_SUCCESS);
    160: }

    162: /*@
    163:   PetscPythonInitialize - Initialize Python for use with PETSc and import petsc4py.

    165:    Input Parameters:
    166: +  pyexe - path to the Python interpreter executable, or `NULL`.
    167: -  pylib - full path to the Python dynamic library, or `NULL`.

    169:   Level: intermediate

    171: .seealso: `PetscPythonFinalize()`, `PetscPythonPrintError()`
    172: @*/
    173: PetscErrorCode PetscPythonInitialize(const char pyexe[], const char pylib[])
    174: {
    175:   PyObject *module = NULL;

    177:   PetscFunctionBegin;
    178:   if (PetscBeganPython) PetscFunctionReturn(PETSC_SUCCESS);
    179:   /* Python executable */
    180:   if (pyexe && pyexe[0] != 0) {
    181:     PetscCall(PetscStrncpy(PetscPythonExe, pyexe, sizeof(PetscPythonExe)));
    182:   } else {
    183:     PetscCall(PetscPythonFindExecutable(PetscPythonExe, sizeof(PetscPythonExe)));
    184:   }
    185:   /* Python dynamic library */
    186:   if (pylib && pylib[0] != 0) {
    187:     PetscCall(PetscStrncpy(PetscPythonLib, pylib, sizeof(PetscPythonLib)));
    188:   } else {
    189:     PetscCall(PetscPythonFindLibrary(PetscPythonExe, PetscPythonLib, sizeof(PetscPythonLib)));
    190:   }
    191:   /* dynamically load Python library */
    192:   PetscCall(PetscPythonLoadLibrary(PetscPythonLib));
    193:   /* initialize Python */
    194:   PetscBeganPython = PETSC_FALSE;
    195:   if (!Py_IsInitialized()) {
    196:     static PetscBool registered = PETSC_FALSE;
    197:     const char      *py_version;
    198:     PyObject        *sys_path;
    199:     char             path[PETSC_MAX_PATH_LEN] = {0};

    201:     /* initialize Python. Py_InitializeEx() prints an error and EXITS the program if it is not successful! */
    202:     PetscCall(PetscInfo(NULL, "Calling Py_InitializeEx(0)\n"));
    203:     PetscStackCallExternalVoid("Py_InitializeEx", Py_InitializeEx(0)); /* 0: do not install signal handlers */
    204:     PetscCall(PetscInfo(NULL, "Py_InitializeEx(0) called successfully\n"));

    206:     /* build 'sys.argv' list */
    207:     py_version = Py_GetVersion();
    208:     if (py_version[0] == '2') {
    209:       int   argc    = 0;
    210:       char *argv[1] = {NULL};
    211:       PySys_SetArgv(argc, argv);
    212:     }
    213:     if (py_version[0] == '3') {
    214:       int      argc    = 0;
    215:       wchar_t *argv[1] = {NULL};
    216:       PySys_SetArgv(argc, argv);
    217:     }
    218:     /* add PETSC_LIB_DIR in front of 'sys.path' */
    219:     sys_path = PySys_GetObject("path");
    220:     if (sys_path) {
    221:       int zero = 0;
    222:       PetscCall(PetscStrreplace(PETSC_COMM_SELF, "${PETSC_LIB_DIR}", path, sizeof(path)));
    223:       Py_DecRef(PyObject_CallMethod(sys_path, "insert", "is", zero, (char *)path));
    224: #if defined(PETSC_PETSC4PY_INSTALL_PATH)
    225:       {
    226:         char *rpath;
    227:         PetscCall(PetscStrallocpy(PETSC_PETSC4PY_INSTALL_PATH, &rpath));
    228:         Py_DecRef(PyObject_CallMethod(sys_path, "insert", "is", zero, rpath));
    229:         PetscCall(PetscFree(rpath));
    230:       }
    231: #endif
    232:     }
    233:     /* register finalizer */
    234:     if (!registered) {
    235:       PetscCall(PetscRegisterFinalize(PetscPythonFinalize));
    236:       registered = PETSC_TRUE;
    237:     }
    238:     PetscBeganPython = PETSC_TRUE;
    239:     PetscCall(PetscInfo(NULL, "Python initialize completed\n"));
    240:   }
    241:   /* import 'petsc4py.PETSc' module */
    242:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
    243:   PetscStackCallExternalVoid("PyImport_ImportModule", module = PyImport_ImportModule("petsc4py.PETSc"));
    244:   PetscCall(PetscFPTrapPop());
    245:   if (module) {
    246:     PetscCall(PetscInfo(NULL, "Python: successfully imported module 'petsc4py.PETSc'\n"));
    247:     Py_DecRef(module);
    248:     module = NULL;
    249:   } else {
    250:     PetscCall(PetscInfo(NULL, "Python: error when importing module 'petsc4py.PETSc'\n"));
    251:     PetscCall(PetscPythonPrintError());
    252:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Python: could not import module 'petsc4py.PETSc', perhaps your PYTHONPATH does not contain it");
    253:   }
    254:   PetscFunctionReturn(PETSC_SUCCESS);
    255: }

    257: /*@C
    258:   PetscPythonPrintError - Print any current Python errors.

    260:   Level: developer

    262: .seealso: `PetscPythonInitialize()`, `PetscPythonFinalize()`
    263: @*/
    264: PetscErrorCode PetscPythonPrintError(void)
    265: {
    266:   PyObject *exc = NULL, *val = NULL, *tb = NULL;

    268:   PetscFunctionBegin;
    269:   if (!PetscBeganPython) PetscFunctionReturn(PETSC_SUCCESS);
    270:   if (!PyErr_Occurred()) PetscFunctionReturn(PETSC_SUCCESS);
    271:   PyErr_Fetch(&exc, &val, &tb);
    272:   PyErr_NormalizeException(&exc, &val, &tb);
    273:   PyErr_Display(exc ? exc : Py_None, val ? val : Py_None, tb ? tb : Py_None);
    274:   PyErr_Restore(exc, val, tb);
    275:   PetscFunctionReturn(PETSC_SUCCESS);
    276: }

    278: PETSC_EXTERN PetscErrorCode (*PetscPythonMonitorSet_C)(PetscObject, const char[]);
    279: PetscErrorCode (*PetscPythonMonitorSet_C)(PetscObject, const char[]) = NULL;

    281: /*@
    282:   PetscPythonMonitorSet - Set a Python monitor for a `PetscObject`

    284:   Level: developer

    286: .seealso: `PetscPythonInitialize()`, `PetscPythonFinalize()`, `PetscPythonPrintError()`
    287: @*/
    288: PetscErrorCode PetscPythonMonitorSet(PetscObject obj, const char url[])
    289: {
    290:   PetscFunctionBegin;
    292:   PetscAssertPointer(url, 2);
    293:   if (!PetscPythonMonitorSet_C) {
    294:     PetscCall(PetscPythonInitialize(NULL, NULL));
    295:     PetscCheck(PetscPythonMonitorSet_C, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Couldn't initialize Python support for monitors");
    296:   }
    297:   PetscCall(PetscPythonMonitorSet_C(obj, url));
    298:   PetscFunctionReturn(PETSC_SUCCESS);
    299: }