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From 42123e9614ea73c7f64c684c90e4dbb049ef67ef Mon Sep 17 00:00:00 2001
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From: Frantisek Sumsal <frantisek@sumsal.cz>
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Date: Sun, 5 Dec 2021 10:25:28 +0100
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Subject: [PATCH] lgtm: ignore certain cleanup functions
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as they don't do any illegal stuff even when used with an uninitialized
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variable.
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(cherry picked from commit af1868213657b38b8d4008608976eb81546cfb8e)
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Related: #2017033
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---
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 .lgtm/cpp-queries/UninitializedVariableWithCleanup.ql | 9 +++++++++
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 1 file changed, 9 insertions(+)
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diff --git a/.lgtm/cpp-queries/UninitializedVariableWithCleanup.ql b/.lgtm/cpp-queries/UninitializedVariableWithCleanup.ql
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index 6bf0ae01eb..8c24b6d8f1 100644
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--- a/.lgtm/cpp-queries/UninitializedVariableWithCleanup.ql
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+++ b/.lgtm/cpp-queries/UninitializedVariableWithCleanup.ql
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@@ -34,6 +34,13 @@ predicate allocatedType(Type t) {
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   allocatedType(t.getUnspecifiedType())
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 }
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+/** Auxiliary predicate: List cleanup functions we want to explicitly ignore
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+  * since they don't do anything illegal even when the variable is uninitialized
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+  */
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+predicate cleanupFunctionDenyList(string fun) {
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+  fun = "erase_char"
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+}
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+
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 /**
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  * A declaration of a local variable using __attribute__((__cleanup__(x)))
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  * that leaves the variable uninitialized.
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@@ -43,6 +50,8 @@ DeclStmt declWithNoInit(LocalVariable v) {
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   not exists(v.getInitializer()) and
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   /* The variable has __attribute__((__cleanup__(...))) set */
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   v.getAnAttribute().hasName("cleanup") and
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+  /* Check if the cleanup function is not on a deny list */
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+  not exists(Attribute a | a = v.getAnAttribute() and a.getName() = "cleanup" | cleanupFunctionDenyList(a.getAnArgument().getValueText())) and
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   /* The type of the variable is not stack-allocated. */
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   exists(Type t | t = v.getType() | not allocatedType(t))
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 }