plpy_plpymodule.c

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/*
 * the plpy module
 *
 * src/pl/plpython/plpy_plpymodule.c
 */

#include "postgres.h"

#include "access/xact.h"
#include "mb/pg_wchar.h"
#include "plpy_cursorobject.h"
#include "plpy_elog.h"
#include "plpy_main.h"
#include "plpy_planobject.h"
#include "plpy_plpymodule.h"
#include "plpy_resultobject.h"
#include "plpy_spi.h"
#include "plpy_subxactobject.h"
#include "plpython.h"
#include "utils/builtins.h"
#include "utils/snapmgr.h"

HTAB       *PLy_spi_exceptions = NULL;


static void PLy_add_exceptions(PyObject *plpy);
static PyObject *PLy_create_exception(char *name,
                                      PyObject *base, PyObject *dict,
                                      const char *modname, PyObject *mod);
static void PLy_generate_spi_exceptions(PyObject *mod, PyObject *base);

/* module functions */
static PyObject *PLy_debug(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_log(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_info(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_notice(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_warning(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_error(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_fatal(PyObject *self, PyObject *args, PyObject *kw);
static PyObject *PLy_quote_literal(PyObject *self, PyObject *args);
static PyObject *PLy_quote_nullable(PyObject *self, PyObject *args);
static PyObject *PLy_quote_ident(PyObject *self, PyObject *args);
static PyObject *PLy_commit(PyObject *self, PyObject *args);
static PyObject *PLy_rollback(PyObject *self, PyObject *args);


/* A list of all known exceptions, generated from backend/utils/errcodes.txt */
typedef struct ExceptionMap
{
    char       *name;
    char       *classname;
    int         sqlstate;
} ExceptionMap;

static const ExceptionMap exception_map[] = {
#include "spiexceptions.h"
    {NULL, NULL, 0}
};

static PyMethodDef PLy_methods[] = {
    /*
     * logging methods
     */
    {"debug", (PyCFunction) (pg_funcptr_t) PLy_debug, METH_VARARGS | METH_KEYWORDS, NULL},
    {"log", (PyCFunction) (pg_funcptr_t) PLy_log, METH_VARARGS | METH_KEYWORDS, NULL},
    {"info", (PyCFunction) (pg_funcptr_t) PLy_info, METH_VARARGS | METH_KEYWORDS, NULL},
    {"notice", (PyCFunction) (pg_funcptr_t) PLy_notice, METH_VARARGS | METH_KEYWORDS, NULL},
    {"warning", (PyCFunction) (pg_funcptr_t) PLy_warning, METH_VARARGS | METH_KEYWORDS, NULL},
    {"error", (PyCFunction) (pg_funcptr_t) PLy_error, METH_VARARGS | METH_KEYWORDS, NULL},
    {"fatal", (PyCFunction) (pg_funcptr_t) PLy_fatal, METH_VARARGS | METH_KEYWORDS, NULL},

    /*
     * create a stored plan
     */
    {"prepare", PLy_spi_prepare, METH_VARARGS, NULL},

    /*
     * execute a plan or query
     */
    {"execute", PLy_spi_execute, METH_VARARGS, NULL},

    /*
     * escaping strings
     */
    {"quote_literal", PLy_quote_literal, METH_VARARGS, NULL},
    {"quote_nullable", PLy_quote_nullable, METH_VARARGS, NULL},
    {"quote_ident", PLy_quote_ident, METH_VARARGS, NULL},

    /*
     * create the subtransaction context manager
     */
    {"subtransaction", PLy_subtransaction_new, METH_NOARGS, NULL},

    /*
     * create a cursor
     */
    {"cursor", PLy_cursor, METH_VARARGS, NULL},

    /*
     * transaction control
     */
    {"commit", PLy_commit, METH_NOARGS, NULL},
    {"rollback", PLy_rollback, METH_NOARGS, NULL},

    {NULL, NULL, 0, NULL}
};

static PyMethodDef PLy_exc_methods[] = {
    {NULL, NULL, 0, NULL}
};

#if PY_MAJOR_VERSION >= 3
static PyModuleDef PLy_module = {
    PyModuleDef_HEAD_INIT,
    .m_name = "plpy",
    .m_size = -1,
    .m_methods = PLy_methods,
};

static PyModuleDef PLy_exc_module = {
    PyModuleDef_HEAD_INIT,
    .m_name = "spiexceptions",
    .m_size = -1,
    .m_methods = PLy_exc_methods,
};

/*
 * Must have external linkage, because PyMODINIT_FUNC does dllexport on
 * Windows-like platforms.
 */
PyMODINIT_FUNC
PyInit_plpy(void)
{
    PyObject   *m;

    m = PyModule_Create(&PLy_module);
    if (m == NULL)
        return NULL;

    PLy_add_exceptions(m);

    return m;
}
#endif                          /* PY_MAJOR_VERSION >= 3 */

void
PLy_init_plpy(void)
{
    PyObject   *main_mod,
               *main_dict,
               *plpy_mod;

#if PY_MAJOR_VERSION < 3
    PyObject   *plpy;
#endif

    /*
     * initialize plpy module
     */
    PLy_plan_init_type();
    PLy_result_init_type();
    PLy_subtransaction_init_type();
    PLy_cursor_init_type();

#if PY_MAJOR_VERSION >= 3
    PyModule_Create(&PLy_module);
    /* for Python 3 we initialized the exceptions in PyInit_plpy */
#else
    plpy = Py_InitModule("plpy", PLy_methods);
    PLy_add_exceptions(plpy);
#endif

    /* PyDict_SetItemString(plpy, "PlanType", (PyObject *) &PLy_PlanType); */

    /*
     * initialize main module, and add plpy
     */
    main_mod = PyImport_AddModule("__main__");
    main_dict = PyModule_GetDict(main_mod);
    plpy_mod = PyImport_AddModule("plpy");
    if (plpy_mod == NULL)
        PLy_elog(ERROR, "could not import \"plpy\" module");
    PyDict_SetItemString(main_dict, "plpy", plpy_mod);
    if (PyErr_Occurred())
        PLy_elog(ERROR, "could not import \"plpy\" module");
}

static void
PLy_add_exceptions(PyObject *plpy)
{
    PyObject   *excmod;
    HASHCTL     hash_ctl;

#if PY_MAJOR_VERSION < 3
    excmod = Py_InitModule("spiexceptions", PLy_exc_methods);
#else
    excmod = PyModule_Create(&PLy_exc_module);
#endif
    if (excmod == NULL)
        PLy_elog(ERROR, "could not create the spiexceptions module");

    /*
     * PyModule_AddObject does not add a refcount to the object, for some odd
     * reason; we must do that.
     */
    Py_INCREF(excmod);
    if (PyModule_AddObject(plpy, "spiexceptions", excmod) < 0)
        PLy_elog(ERROR, "could not add the spiexceptions module");

    PLy_exc_error = PLy_create_exception("plpy.Error", NULL, NULL,
                                         "Error", plpy);
    PLy_exc_fatal = PLy_create_exception("plpy.Fatal", NULL, NULL,
                                         "Fatal", plpy);
    PLy_exc_spi_error = PLy_create_exception("plpy.SPIError", NULL, NULL,
                                             "SPIError", plpy);

    hash_ctl.keysize = sizeof(int);
    hash_ctl.entrysize = sizeof(PLyExceptionEntry);
    PLy_spi_exceptions = hash_create("PL/Python SPI exceptions", 256,
                                     &hash_ctl, HASH_ELEM | HASH_BLOBS);

    PLy_generate_spi_exceptions(excmod, PLy_exc_spi_error);
}

/*
 * Create an exception object and add it to the module
 */
static PyObject *
PLy_create_exception(char *name, PyObject *base, PyObject *dict,
                     const char *modname, PyObject *mod)
{
    PyObject   *exc;

    exc = PyErr_NewException(name, base, dict);
    if (exc == NULL)
        PLy_elog(ERROR, NULL);

    /*
     * PyModule_AddObject does not add a refcount to the object, for some odd
     * reason; we must do that.
     */
    Py_INCREF(exc);
    PyModule_AddObject(mod, modname, exc);

    /*
     * The caller will also store a pointer to the exception object in some
     * permanent variable, so add another ref to account for that.  This is
     * probably excessively paranoid, but let's be sure.
     */
    Py_INCREF(exc);
    return exc;
}

/*
 * Add all the autogenerated exceptions as subclasses of SPIError
 */
static void
PLy_generate_spi_exceptions(PyObject *mod, PyObject *base)
{
    int         i;

    for (i = 0; exception_map[i].name != NULL; i++)
    {
        bool        found;
        PyObject   *exc;
        PLyExceptionEntry *entry;
        PyObject   *sqlstate;
        PyObject   *dict = PyDict_New();

        if (dict == NULL)
            PLy_elog(ERROR, NULL);

        sqlstate = PyString_FromString(unpack_sql_state(exception_map[i].sqlstate));
        if (sqlstate == NULL)
            PLy_elog(ERROR, "could not generate SPI exceptions");

        PyDict_SetItemString(dict, "sqlstate", sqlstate);
        Py_DECREF(sqlstate);

        exc = PLy_create_exception(exception_map[i].name, base, dict,
                                   exception_map[i].classname, mod);

        entry = hash_search(PLy_spi_exceptions, &exception_map[i].sqlstate,
                            HASH_ENTER, &found);
        Assert(!found);
        entry->exc = exc;
    }
}


/*
 * the python interface to the elog function
 * don't confuse these with PLy_elog
 */
static PyObject *PLy_output(volatile int level, PyObject *self,
                            PyObject *args, PyObject *kw);

static PyObject *
PLy_debug(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(DEBUG2, self, args, kw);
}

static PyObject *
PLy_log(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(LOG, self, args, kw);
}

static PyObject *
PLy_info(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(INFO, self, args, kw);
}

static PyObject *
PLy_notice(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(NOTICE, self, args, kw);
}

static PyObject *
PLy_warning(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(WARNING, self, args, kw);
}

static PyObject *
PLy_error(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(ERROR, self, args, kw);
}

static PyObject *
PLy_fatal(PyObject *self, PyObject *args, PyObject *kw)
{
    return PLy_output(FATAL, self, args, kw);
}

static PyObject *
PLy_quote_literal(PyObject *self, PyObject *args)
{
    const char *str;
    char       *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "s:quote_literal", &str))
        return NULL;

    quoted = quote_literal_cstr(str);
    ret = PyString_FromString(quoted);
    pfree(quoted);

    return ret;
}

static PyObject *
PLy_quote_nullable(PyObject *self, PyObject *args)
{
    const char *str;
    char       *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "z:quote_nullable", &str))
        return NULL;

    if (str == NULL)
        return PyString_FromString("NULL");

    quoted = quote_literal_cstr(str);
    ret = PyString_FromString(quoted);
    pfree(quoted);

    return ret;
}

static PyObject *
PLy_quote_ident(PyObject *self, PyObject *args)
{
    const char *str;
    const char *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "s:quote_ident", &str))
        return NULL;

    quoted = quote_identifier(str);
    ret = PyString_FromString(quoted);

    return ret;
}

/* enforce cast of object to string */
static char *
object_to_string(PyObject *obj)
{
    if (obj)
    {
        PyObject   *so = PyObject_Str(obj);

        if (so != NULL)
        {
            char       *str;

            str = pstrdup(PyString_AsString(so));
            Py_DECREF(so);

            return str;
        }
    }

    return NULL;
}

static PyObject *
PLy_output(volatile int level, PyObject *self, PyObject *args, PyObject *kw)
{
    int         sqlstate = 0;
    char       *volatile sqlstatestr = NULL;
    char       *volatile message = NULL;
    char       *volatile detail = NULL;
    char       *volatile hint = NULL;
    char       *volatile column_name = NULL;
    char       *volatile constraint_name = NULL;
    char       *volatile datatype_name = NULL;
    char       *volatile table_name = NULL;
    char       *volatile schema_name = NULL;
    volatile MemoryContext oldcontext;
    PyObject   *key,
               *value;
    PyObject   *volatile so;
    Py_ssize_t  pos = 0;

    if (PyTuple_Size(args) == 1)
    {
        /*
         * Treat single argument specially to avoid undesirable ('tuple',)
         * decoration.
         */
        PyObject   *o;

        if (!PyArg_UnpackTuple(args, "plpy.elog", 1, 1, &o))
            PLy_elog(ERROR, "could not unpack arguments in plpy.elog");
        so = PyObject_Str(o);
    }
    else
        so = PyObject_Str(args);

    if (so == NULL || ((message = PyString_AsString(so)) == NULL))
    {
        level = ERROR;
        message = dgettext(TEXTDOMAIN, "could not parse error message in plpy.elog");
    }
    message = pstrdup(message);

    Py_XDECREF(so);

    if (kw != NULL)
    {
        while (PyDict_Next(kw, &pos, &key, &value))
        {
            char       *keyword = PyString_AsString(key);

            if (strcmp(keyword, "message") == 0)
            {
                /* the message should not be overwritten */
                if (PyTuple_Size(args) != 0)
                {
                    PLy_exception_set(PyExc_TypeError, "argument 'message' given by name and position");
                    return NULL;
                }

                if (message)
                    pfree(message);
                message = object_to_string(value);
            }
            else if (strcmp(keyword, "detail") == 0)
                detail = object_to_string(value);
            else if (strcmp(keyword, "hint") == 0)
                hint = object_to_string(value);
            else if (strcmp(keyword, "sqlstate") == 0)
                sqlstatestr = object_to_string(value);
            else if (strcmp(keyword, "schema_name") == 0)
                schema_name = object_to_string(value);
            else if (strcmp(keyword, "table_name") == 0)
                table_name = object_to_string(value);
            else if (strcmp(keyword, "column_name") == 0)
                column_name = object_to_string(value);
            else if (strcmp(keyword, "datatype_name") == 0)
                datatype_name = object_to_string(value);
            else if (strcmp(keyword, "constraint_name") == 0)
                constraint_name = object_to_string(value);
            else
            {
                PLy_exception_set(PyExc_TypeError,
                                  "'%s' is an invalid keyword argument for this function",
                                  keyword);
                return NULL;
            }
        }
    }

    if (sqlstatestr != NULL)
    {
        if (strlen(sqlstatestr) != 5)
        {
            PLy_exception_set(PyExc_ValueError, "invalid SQLSTATE code");
            return NULL;
        }

        if (strspn(sqlstatestr, "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ") != 5)
        {
            PLy_exception_set(PyExc_ValueError, "invalid SQLSTATE code");
            return NULL;
        }

        sqlstate = MAKE_SQLSTATE(sqlstatestr[0],
                                 sqlstatestr[1],
                                 sqlstatestr[2],
                                 sqlstatestr[3],
                                 sqlstatestr[4]);
    }

    oldcontext = CurrentMemoryContext;
    PG_TRY();
    {
        if (message != NULL)
            pg_verifymbstr(message, strlen(message), false);
        if (detail != NULL)
            pg_verifymbstr(detail, strlen(detail), false);
        if (hint != NULL)
            pg_verifymbstr(hint, strlen(hint), false);
        if (schema_name != NULL)
            pg_verifymbstr(schema_name, strlen(schema_name), false);
        if (table_name != NULL)
            pg_verifymbstr(table_name, strlen(table_name), false);
        if (column_name != NULL)
            pg_verifymbstr(column_name, strlen(column_name), false);
        if (datatype_name != NULL)
            pg_verifymbstr(datatype_name, strlen(datatype_name), false);
        if (constraint_name != NULL)
            pg_verifymbstr(constraint_name, strlen(constraint_name), false);

        ereport(level,
                ((sqlstate != 0) ? errcode(sqlstate) : 0,
                 (message != NULL) ? errmsg_internal("%s", message) : 0,
                 (detail != NULL) ? errdetail_internal("%s", detail) : 0,
                 (hint != NULL) ? errhint("%s", hint) : 0,
                 (column_name != NULL) ?
                 err_generic_string(PG_DIAG_COLUMN_NAME, column_name) : 0,
                 (constraint_name != NULL) ?
                 err_generic_string(PG_DIAG_CONSTRAINT_NAME, constraint_name) : 0,
                 (datatype_name != NULL) ?
                 err_generic_string(PG_DIAG_DATATYPE_NAME, datatype_name) : 0,
                 (table_name != NULL) ?
                 err_generic_string(PG_DIAG_TABLE_NAME, table_name) : 0,
                 (schema_name != NULL) ?
                 err_generic_string(PG_DIAG_SCHEMA_NAME, schema_name) : 0));
    }
    PG_CATCH();
    {
        ErrorData  *edata;

        MemoryContextSwitchTo(oldcontext);
        edata = CopyErrorData();
        FlushErrorState();

        PLy_exception_set_with_details(PLy_exc_error, edata);
        FreeErrorData(edata);

        return NULL;
    }
    PG_END_TRY();

    /*
     * return a legal object so the interpreter will continue on its merry way
     */
    Py_RETURN_NONE;
}

static PyObject *
PLy_commit(PyObject *self, PyObject *args)
{
    PLyExecutionContext *exec_ctx = PLy_current_execution_context();

    SPI_commit();
    SPI_start_transaction();

    /* was cleared at transaction end, reset pointer */
    exec_ctx->scratch_ctx = NULL;

    Py_RETURN_NONE;
}

static PyObject *
PLy_rollback(PyObject *self, PyObject *args)
{
    PLyExecutionContext *exec_ctx = PLy_current_execution_context();

    SPI_rollback();
    SPI_start_transaction();

    /* was cleared at transaction end, reset pointer */
    exec_ctx->scratch_ctx = NULL;

    Py_RETURN_NONE;
}