CON40-C

Author: jsinglet

.vscode/settings.json

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+{
+    "files.associations": {
+        "atomic": "c",
+        "memory": "c"
+    }
+}

c/cert/src/rules/CON39-C/ThreadWasPreviouslyJoinedOrDetached.md

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+# CON39-C: Do not join or detach a thread that was previously joined or detached
+
+This query implements the CERT-C rule CON39-C:
+
+> Do not join or detach a thread that was previously joined or detached
+
+
+## CERT
+
+** REPLACE THIS BY RUNNING THE SCRIPT `scripts/help/cert-help-extraction.py` **
+
+## Implementation notes
+
+None
+
+## References
+
+* CERT-C: [CON39-C: Do not join or detach a thread that was previously joined or detached](https://wiki.sei.cmu.edu/confluence/display/c)

c/cert/src/rules/CON39-C/ThreadWasPreviouslyJoinedOrDetached.ql

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+/**
+ * @id c/cert/thread-was-previously-joined-or-detached
+ * @name CON39-C: Do not join or detach a thread that was previously joined or detached
+ * @description Joining or detaching a previously joined or detached thread can lead to undefined
+ *              program behavior.
+ * @kind problem
+ * @precision high
+ * @problem.severity error
+ * @tags external/cert/id/con39-c
+ *       correctness
+ *       concurrency
+ *       external/cert/obligation/rule
+ */
+
+import cpp
+import codingstandards.c.cert
+
+
+
+/**
+ * Strategy for this one is to ensure that there are not two sinks to thrd_join
+   or thrd_detach for a given 
+
+
+   Truth table:
+
+   Error if:
+
+   thread calls detach, parent calls join
+   thread calls 
+
+   Make sure there aren't multiple calls to join? Very had to do in practice. 
+
+   You should call join OR detach, but not both. 
+ */
+
+from
+where
+  not isExcluded(x, Concurrency5Package::threadWasPreviouslyJoinedOrDetachedQuery()) and
+select

c/cert/src/rules/CON40-C/AtomicVariableTwiceInExpression.md

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+# CON40-C: Do not refer to an atomic variable twice in an expression
+
+This query implements the CERT-C rule CON40-C:
+
+> Do not refer to an atomic variable twice in an expression
+
+
+## CERT
+
+** REPLACE THIS BY RUNNING THE SCRIPT `scripts/help/cert-help-extraction.py` **
+
+## Implementation notes
+
+None
+
+## References
+
+* CERT-C: [CON40-C: Do not refer to an atomic variable twice in an expression](https://wiki.sei.cmu.edu/confluence/display/c)

c/cert/src/rules/CON40-C/AtomicVariableTwiceInExpression.ql

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+/**
+ * @id c/cert/atomic-variable-twice-in-expression
+ * @name CON40-C: Do not refer to an atomic variable twice in an expression
+ * @description Atomic variables that are referred to twice in the same expression can produce
+ *              unpredictable program behavior.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/cert/id/con40-c
+ *       correctness
+ *       concurrency
+ *       external/cert/obligation/rule
+ */
+
+import cpp
+import codingstandards.c.cert
+
+from MacroInvocation mi, Variable v, Locatable whereFound
+where
+  not isExcluded(whereFound, Concurrency5Package::atomicVariableTwiceInExpressionQuery()) and
+  (
+    // There isn't a way to safely use this construct in a away that is also
+    // possible the reliably detect so advise against using it.
+    (
+      mi.getMacroName() = ["atomic_store", "atomic_store_explicit"]
+      or
+      // This construct is generally safe, but must be used in a loop. To lower
+      // the false positive rate we don't look at the conditions of the loop and
+      // instead assume if it is found in a looping construct that it is likely
+      // related to the safety property.
+      mi.getMacroName() = ["atomic_compare_exchange_weak", "atomic_compare_exchange_weak_explicit"] and
+      not exists(Loop l | mi.getAGeneratedElement().(Expr).getParent*() = l)
+    ) and
+    whereFound = mi
+  )
+  or
+  mi.getMacroName() = "ATOMIC_VAR_INIT" and
+  exists(Expr av |
+    av = mi.getAGeneratedElement() and
+    av = v.getAnAssignedValue() and
+    exists(Assignment m |
+      not m instanceof AssignXorExpr and
+      m.getLValue().(VariableAccess).getTarget() = v and
+      whereFound = m
+    )
+  )
+select mi, "Atomic variable possibly referred to twice in an $@.", whereFound, "expression"

c/cert/test/rules/CON39-C/ThreadWasPreviouslyJoinedOrDetached.expected

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+No expected results have yet been specified

c/cert/test/rules/CON39-C/ThreadWasPreviouslyJoinedOrDetached.qlref

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+rules/CON39-C/ThreadWasPreviouslyJoinedOrDetached.ql

c/cert/test/rules/CON39-C/test.c

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+| test.c:6:19:6:40 | ATOMIC_VAR_INIT(value) | Atomic variable possibly referred to twice in an $@. | test.c:32:3:32:10 | ... += ... | expression |
+| test.c:6:19:6:40 | ATOMIC_VAR_INIT(value) | Atomic variable possibly referred to twice in an $@. | test.c:33:3:33:13 | ... = ... | expression |
+| test.c:10:3:10:23 | atomic_store(a,b) | Atomic variable possibly referred to twice in an $@. | test.c:10:3:10:23 | atomic_store(a,b) | expression |
+| test.c:11:3:11:35 | atomic_store_explicit(a,b,c) | Atomic variable possibly referred to twice in an $@. | test.c:11:3:11:35 | atomic_store_explicit(a,b,c) | expression |
+| test.c:24:3:24:48 | atomic_compare_exchange_weak(a,b,c) | Atomic variable possibly referred to twice in an $@. | test.c:24:3:24:48 | atomic_compare_exchange_weak(a,b,c) | expression |
+| test.c:25:3:26:45 | atomic_compare_exchange_weak_explicit(a,b,c,d,e) | Atomic variable possibly referred to twice in an $@. | test.c:25:3:26:45 | atomic_compare_exchange_weak_explicit(a,b,c,d,e) | expression |

c/cert/test/rules/CON40-C/AtomicVariableTwiceInExpression.expected

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+rules/CON40-C/AtomicVariableTwiceInExpression.ql