lib: rework how we "override" assert()

The previous method, using zassert.h and hoping nothing includes
assert.h (which, on glibc at least, just does "#undef assert" and puts
its own definition in...) was fragile - and actually broke undetected.

Just provide our own assert.h and control overriding by putting it in a
separate directory to add to the include path (or not.)

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/lib/zlog.c b/lib/zlog.c
index 24800c6e6..d2851c602 100644
--- a/lib/zlog.c
+++ b/lib/zlog.c
@@ -521,6 +521,36 @@ void zlog_sigsafe(const char *text, size_t len)
 	}
 }
 
+void _zlog_assert_failed(const struct xref_assert *xref, const char *extra, ...)
+{
+	va_list ap;
+	static bool assert_in_assert; /* "global-ish" variable, init to 0 */
+
+	if (assert_in_assert)
+		abort();
+	assert_in_assert = true;
+
+	if (extra) {
+		struct va_format vaf;
+
+		va_start(ap, extra);
+		vaf.fmt = extra;
+		vaf.va = ≈
+
+		zlog(LOG_CRIT,
+		     "%s:%d: %s(): assertion (%s) failed, extra info: %pVA",
+		     xref->xref.file, xref->xref.line, xref->xref.func,
+		     xref->expr, &vaf);
+
+		va_end(ap);
+	} else
+		zlog(LOG_CRIT, "%s:%d: %s(): assertion (%s) failed",
+		     xref->xref.file, xref->xref.line, xref->xref.func,
+		     xref->expr);
+
+	/* abort() prints backtrace & memstats in SIGABRT handler */
+	abort();
+}
 
 int zlog_msg_prio(struct zlog_msg *msg)
 {