Andrew Kesterson
de13b290d4
Two memory-safety bugs in the macro core: 1. Refcount leak. ENSURE_ERROR_READY incremented refcount on every FAIL/SUCCEED rather than only when it acquired a fresh context from the pool. A function that FAILed a context more than once and then propagated arrived at its caller with refcount 2; the caller released once, leaking the slot. After AKERR_MAX_ARRAY_ERROR leaks the pool is exhausted and the library exit(1)s. Move the increment inside the acquisition branch. 2. Stack-trace overflow. Each appended frame passed the full buffer length to snprintf instead of the space remaining, and advanced the cursor by snprintf's would-be return value, so a trace that filled the buffer wrote past the end of stacktracebuf and ran the cursor out of bounds. Add AKERR_STACKTRACE_APPEND, which bounds the write to the remaining space and clamps the cursor advance. Regression tests err_refcount_double_fail and err_stacktrace_bounds fail against the old code (verified) and pass now. Full suite: 21/21, no warnings. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
#include "akerror.h"
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#include "err_capture.h"
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/*
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* Regression test for the refcount leak: ENSURE_ERROR_READY must increment
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* refcount only when it *acquires* a fresh context, not on every FAIL/SUCCEED.
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* A function that calls FAIL more than once on the same context and then
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* propagates used to arrive at the caller with refcount 2; the caller released
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* once, leaking the slot. After enough leaks the pool is exhausted and the
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* library exit(1)s.
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*/
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akerr_ErrorContext *validate(void)
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{
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PREPARE_ERROR(e);
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ATTEMPT {
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FAIL(e, AKERR_VALUE, "condition 1 failed"); /* acquires the context */
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FAIL(e, AKERR_KEY, "condition 2 failed"); /* must NOT re-acquire it */
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} CLEANUP {
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} PROCESS(e) {
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} FINISH(e, true); /* unhandled -> propagate */
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SUCCEED_RETURN(e);
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}
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/* One raise -> catch -> handle cycle; returns NULL (context released). */
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akerr_ErrorContext *one_cycle(void)
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{
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PREPARE_ERROR(e);
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ATTEMPT {
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CATCH(e, validate());
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} CLEANUP {
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} PROCESS(e) {
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} HANDLE(e, AKERR_KEY) {
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} HANDLE(e, AKERR_VALUE) {
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} FINISH(e, false);
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return e;
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}
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int main(void)
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{
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akerr_init();
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AKERR_CHECK(akerr_slots_in_use() == 0);
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for ( int i = 0; i < 32; i++ ) {
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(void)one_cycle();
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}
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AKERR_CHECK(akerr_slots_in_use() == 0);
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fprintf(stderr, "err_refcount_double_fail ok\n");
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return 0;
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}
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