42 lines
1.4 KiB
Python
42 lines
1.4 KiB
Python
#!/usr/bin/env python3
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"""Guard _PyMem_DebugRawFree's C89 locals and NULL-safe evaluation order."""
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import re
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import sys
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from pathlib import Path
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source = Path(sys.argv[1]).read_text()
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match = re.search(
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r"\n_PyMem_DebugRawFree\(void \*ctx, void \*p\)\s*\{(.*?)\n\}",
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source, re.S,
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)
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assert match, "_PyMem_DebugRawFree definition not found"
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body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
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declarations = """
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debug_alloc_api_t *api;
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uint8_t *q;
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size_t nbytes;
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"""
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assert body.split()[:len(declarations.split())] == declarations.split(), (
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"_PyMem_DebugRawFree must declare api, q, and nbytes without initializers at function entry"
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)
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# Preserve the NULL return before either initializer is evaluated, especially
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# the pointer subtraction, and retain all subsequent operations in order.
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expected = declarations + """
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if (p == NULL) {
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return;
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}
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api = (debug_alloc_api_t *)ctx;
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q = (uint8_t *)p - 2*SST;
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_PyMem_DebugCheckAddress(__func__, api->api_id, p);
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nbytes = read_size_t(q);
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nbytes += PYMEM_DEBUG_EXTRA_BYTES;
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memset(q, PYMEM_DEADBYTE, nbytes);
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api->alloc.free(api->alloc.ctx, q);
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"""
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assert body.split() == expected.split(), (
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"preserve _PyMem_DebugRawFree assignments after the NULL return and original operation order"
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)
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print("obmalloc _PyMem_DebugRawFree entry declarations and NULL-safe operation order: PASS")
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