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:   Options Database Key:
170: . -python <exe> - Initializes Python, and optionally takes a Python executable name

172:   Level: intermediate

174: .seealso: `PetscPythonFinalize()`, `PetscPythonPrintError()`
175: @*/
176: PetscErrorCode PetscPythonInitialize(const char pyexe[], const char pylib[])
177: {
178:   PyObject *module = NULL;

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

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

209:     /* build 'sys.argv' list */
210:     py_version = Py_GetVersion();
211:     if (py_version[0] == '2') {
212:       int   argc    = 0;
213:       char *argv[1] = {NULL};
214:       PySys_SetArgv(argc, argv);
215:     }
216:     if (py_version[0] == '3') {
217:       int      argc    = 0;
218:       wchar_t *argv[1] = {NULL};
219:       PySys_SetArgv(argc, argv);
220:     }
221:     /* add PETSC_LIB_DIR in front of 'sys.path' */
222:     sys_path = PySys_GetObject("path");
223:     if (sys_path) {
224:       int zero = 0;
225:       PetscCall(PetscStrreplace(PETSC_COMM_SELF, "${PETSC_LIB_DIR}", path, sizeof(path)));
226:       Py_DecRef(PyObject_CallMethod(sys_path, "insert", "is", zero, (char *)path));
227: #if defined(PETSC_PETSC4PY_INSTALL_PATH)
228:       {
229:         char *rpath;
230:         PetscCall(PetscStrallocpy(PETSC_PETSC4PY_INSTALL_PATH, &rpath));
231:         Py_DecRef(PyObject_CallMethod(sys_path, "insert", "is", zero, rpath));
232:         PetscCall(PetscFree(rpath));
233:       }
234: #endif
235:     }
236:     /* register finalizer */
237:     if (!registered) {
238:       PetscCall(PetscRegisterFinalize(PetscPythonFinalize));
239:       registered = PETSC_TRUE;
240:     }
241:     PetscBeganPython = PETSC_TRUE;
242:     PetscCall(PetscInfo(NULL, "Python initialize completed\n"));
243:   }
244:   /* import 'petsc4py.PETSc' module */
245:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
246:   PetscStackCallExternalVoid("PyImport_ImportModule", module = PyImport_ImportModule("petsc4py.PETSc"));
247:   PetscCall(PetscFPTrapPop());
248:   if (module) {
249:     PetscCall(PetscInfo(NULL, "Python: successfully imported module 'petsc4py.PETSc'\n"));
250:     Py_DecRef(module);
251:     module = NULL;
252:   } else {
253:     PetscCall(PetscInfo(NULL, "Python: error when importing module 'petsc4py.PETSc'\n"));
254:     PetscCall(PetscPythonPrintError());
255:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Python: could not import module 'petsc4py.PETSc', perhaps your PYTHONPATH does not contain it");
256:   }
257:   PetscFunctionReturn(PETSC_SUCCESS);
258: }

260: /*@C
261:   PetscPythonPrintError - Print any current Python errors.

263:   Level: developer

265: .seealso: `PetscPythonInitialize()`, `PetscPythonFinalize()`
266: @*/
267: PetscErrorCode PetscPythonPrintError(void)
268: {
269:   PyObject *exc = NULL, *val = NULL, *tb = NULL;

271:   PetscFunctionBegin;
272:   if (!PetscBeganPython) PetscFunctionReturn(PETSC_SUCCESS);
273:   if (!PyErr_Occurred()) PetscFunctionReturn(PETSC_SUCCESS);
274:   PyErr_Fetch(&exc, &val, &tb);
275:   PyErr_NormalizeException(&exc, &val, &tb);
276:   PyErr_Display(exc ? exc : Py_None, val ? val : Py_None, tb ? tb : Py_None);
277:   PyErr_Restore(exc, val, tb);
278:   PetscFunctionReturn(PETSC_SUCCESS);
279: }

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

284: /*@
285:   PetscPythonMonitorSet - Set a Python monitor for a `PetscObject`

287:   Level: developer

289: .seealso: `PetscPythonInitialize()`, `PetscPythonFinalize()`, `PetscPythonPrintError()`
290: @*/
291: PetscErrorCode PetscPythonMonitorSet(PetscObject obj, const char url[])
292: {
293:   PetscFunctionBegin;
295:   PetscAssertPointer(url, 2);
296:   if (!PetscPythonMonitorSet_C) {
297:     PetscCall(PetscPythonInitialize(NULL, NULL));
298:     PetscCheck(PetscPythonMonitorSet_C, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Couldn't initialize Python support for monitors");
299:   }
300:   PetscCall(PetscPythonMonitorSet_C(obj, url));
301:   PetscFunctionReturn(PETSC_SUCCESS);
302: }