| 1 | /*
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| 2 | * A type which wraps a pipe handle in message oriented mode
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| 3 | *
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| 4 | * pipe_connection.c
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| 5 | *
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| 6 | * Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt
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| 7 | */
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| 8 |
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| 9 | #include "multiprocessing.h"
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| 10 |
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| 11 | #define CLOSE(h) CloseHandle(h)
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| 12 |
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| 13 | /*
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| 14 | * Send string to the pipe; assumes in message oriented mode
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| 15 | */
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| 16 |
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| 17 | static Py_ssize_t
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| 18 | conn_send_string(ConnectionObject *conn, char *string, size_t length)
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| 19 | {
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| 20 | DWORD amount_written;
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| 21 | BOOL ret;
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| 22 |
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| 23 | Py_BEGIN_ALLOW_THREADS
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| 24 | ret = WriteFile(conn->handle, string, length, &amount_written, NULL);
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| 25 | Py_END_ALLOW_THREADS
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| 26 |
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| 27 | if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES) {
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| 28 | PyErr_Format(PyExc_ValueError, "Cannnot send %" PY_FORMAT_SIZE_T "d bytes over connection", length);
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| 29 | return MP_STANDARD_ERROR;
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| 30 | }
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| 31 |
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| 32 | return ret ? MP_SUCCESS : MP_STANDARD_ERROR;
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| 33 | }
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| 34 |
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| 35 | /*
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| 36 | * Attempts to read into buffer, or if buffer too small into *newbuffer.
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| 37 | *
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| 38 | * Returns number of bytes read. Assumes in message oriented mode.
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| 39 | */
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| 40 |
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| 41 | static Py_ssize_t
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| 42 | conn_recv_string(ConnectionObject *conn, char *buffer,
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| 43 | size_t buflength, char **newbuffer, size_t maxlength)
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| 44 | {
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| 45 | DWORD left, length, full_length, err;
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| 46 | BOOL ret;
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| 47 | *newbuffer = NULL;
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| 48 |
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| 49 | Py_BEGIN_ALLOW_THREADS
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| 50 | ret = ReadFile(conn->handle, buffer, MIN(buflength, maxlength),
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| 51 | &length, NULL);
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| 52 | Py_END_ALLOW_THREADS
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| 53 | if (ret)
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| 54 | return length;
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| 55 |
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| 56 | err = GetLastError();
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| 57 | if (err != ERROR_MORE_DATA) {
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| 58 | if (err == ERROR_BROKEN_PIPE)
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| 59 | return MP_END_OF_FILE;
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| 60 | return MP_STANDARD_ERROR;
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| 61 | }
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| 62 |
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| 63 | if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, NULL, &left))
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| 64 | return MP_STANDARD_ERROR;
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| 65 |
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| 66 | full_length = length + left;
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| 67 | if (full_length > maxlength)
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| 68 | return MP_BAD_MESSAGE_LENGTH;
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| 69 |
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| 70 | *newbuffer = PyMem_Malloc(full_length);
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| 71 | if (*newbuffer == NULL)
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| 72 | return MP_MEMORY_ERROR;
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| 73 |
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| 74 | memcpy(*newbuffer, buffer, length);
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| 75 |
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| 76 | Py_BEGIN_ALLOW_THREADS
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| 77 | ret = ReadFile(conn->handle, *newbuffer+length, left, &length, NULL);
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| 78 | Py_END_ALLOW_THREADS
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| 79 | if (ret) {
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| 80 | assert(length == left);
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| 81 | return full_length;
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| 82 | } else {
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| 83 | PyMem_Free(*newbuffer);
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| 84 | return MP_STANDARD_ERROR;
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| 85 | }
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| 86 | }
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| 87 |
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| 88 | /*
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| 89 | * Check whether any data is available for reading
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| 90 | */
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| 91 |
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| 92 | static int
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| 93 | conn_poll(ConnectionObject *conn, double timeout, PyThreadState *_save)
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| 94 | {
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| 95 | DWORD bytes, deadline, delay;
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| 96 | int difference, res;
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| 97 | BOOL block = FALSE;
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| 98 |
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| 99 | if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, &bytes, NULL))
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| 100 | return MP_STANDARD_ERROR;
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| 101 |
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| 102 | if (timeout == 0.0)
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| 103 | return bytes > 0;
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| 104 |
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| 105 | if (timeout < 0.0)
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| 106 | block = TRUE;
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| 107 | else
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| 108 | /* XXX does not check for overflow */
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| 109 | deadline = GetTickCount() + (DWORD)(1000 * timeout + 0.5);
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| 110 |
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| 111 | Sleep(0);
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| 112 |
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| 113 | for (delay = 1 ; ; delay += 1) {
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| 114 | if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, &bytes, NULL))
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| 115 | return MP_STANDARD_ERROR;
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| 116 | else if (bytes > 0)
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| 117 | return TRUE;
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| 118 |
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| 119 | if (!block) {
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| 120 | difference = deadline - GetTickCount();
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| 121 | if (difference < 0)
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| 122 | return FALSE;
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| 123 | if ((int)delay > difference)
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| 124 | delay = difference;
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| 125 | }
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| 126 |
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| 127 | if (delay > 20)
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| 128 | delay = 20;
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| 129 |
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| 130 | Sleep(delay);
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| 131 |
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| 132 | /* check for signals */
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| 133 | Py_BLOCK_THREADS
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| 134 | res = PyErr_CheckSignals();
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| 135 | Py_UNBLOCK_THREADS
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| 136 |
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| 137 | if (res)
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| 138 | return MP_EXCEPTION_HAS_BEEN_SET;
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| 139 | }
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| 140 | }
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| 141 |
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| 142 | /*
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| 143 | * "connection.h" defines the PipeConnection type using the definitions above
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| 144 | */
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| 145 |
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| 146 | #define CONNECTION_NAME "PipeConnection"
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| 147 | #define CONNECTION_TYPE PipeConnectionType
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| 148 |
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| 149 | #include "connection.h"
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