errors: be more robust in handling unexpected fatal errors

Introduce a new error level, ERR_CRITICAL, beyond which we will
minimize the amount of code that will be executed before we die; in
particular don't execute any memory allocations, and if we somehow end
up recursing, abort() immediately.

Basically, "less than panic, more than fatal."

At this point this level is used by nasm_alloc_failed().

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/disasm/ndisasm.c b/disasm/ndisasm.c
index 6b4ca49d..3269c367 100644
--- a/disasm/ndisasm.c
+++ b/disasm/ndisasm.c
@@ -65,12 +65,18 @@ static const char *help =
 static void output_ins(uint64_t, uint8_t *, int, char *);
 static void skip(uint32_t dist, FILE * fp);
 
-static void ndisasm_verror(errflags severity, const char *fmt, va_list va)
+fatal_func nasm_verror_critical(errflags severity, const char *fmt, va_list val)
 {
-    vfprintf(stderr, fmt, va);
+    vfprintf(stderr, fmt, val);
+    exit((severity & ERR_MASK) - ERR_FATAL + 2);
+}
 
-    if (severity & ERR_FATAL)
-	exit(1);
+static void ndisasm_verror(errflags severity, const char *fmt, va_list val)
+{
+    if ((severity & ERR_MASK) >= ERR_FATAL)
+        nasm_verror_critical(severity, fmt, val);
+    else
+        vfprintf(stderr, fmt, val);
 }
 
 int main(int argc, char **argv)