45 lines
1.8 KiB
Diff
45 lines
1.8 KiB
Diff
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# HG changeset patch
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# User Charles-François Natali <cf.natali@gmail.com>
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# Date 1455316761 0
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# Node ID d3662c088db8fb2c89f754031f18b1543419fed9
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# Parent 5715a6d9ff12053e81f7ad75268ac059b079b351
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Issue #24303: Fix random EEXIST upon multiprocessing semaphores creation with
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Linux PID namespaces enabled.
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diff --git a/Modules/_multiprocessing/semaphore.c b/Modules/_multiprocessing/semaphore.c
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--- a/Modules/_multiprocessing/semaphore.c
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+++ b/Modules/_multiprocessing/semaphore.c
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@@ -429,7 +429,7 @@ semlock_new(PyTypeObject *type, PyObject
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int kind, maxvalue, value;
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PyObject *result;
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static char *kwlist[] = {"kind", "value", "maxvalue", NULL};
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- static int counter = 0;
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+ int try = 0;
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if (!PyArg_ParseTupleAndKeywords(args, kwds, "iii", kwlist,
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&kind, &value, &maxvalue))
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@@ -440,10 +440,18 @@ semlock_new(PyTypeObject *type, PyObject
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return NULL;
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}
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- PyOS_snprintf(buffer, sizeof(buffer), "/mp%ld-%d", (long)getpid(), counter++);
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+ /* Create a semaphore with a unique name. The bytes returned by
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+ * _PyOS_URandom() are treated as unsigned long to ensure that the filename
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+ * is valid (no special characters). */
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+ do {
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+ unsigned long suffix;
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+ _PyOS_URandom((char *)&suffix, sizeof(suffix));
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+ PyOS_snprintf(buffer, sizeof(buffer), "/mp%ld-%lu", (long)getpid(),
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+ suffix);
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+ SEM_CLEAR_ERROR();
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+ handle = SEM_CREATE(buffer, value, maxvalue);
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+ } while ((handle == SEM_FAILED) && (errno == EEXIST) && (++try < 100));
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- SEM_CLEAR_ERROR();
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- handle = SEM_CREATE(buffer, value, maxvalue);
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/* On Windows we should fail if GetLastError()==ERROR_ALREADY_EXISTS */
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if (handle == SEM_FAILED || SEM_GET_LAST_ERROR() != 0)
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goto failure;
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