I stole the printk_once() macro.
I always wanted to be able to print some error directly if there is a
buffer to dump, however we can't use error_report() where the code path
can be triggered by DDOS attack. To avoid that, we can introduce a
print-once-like function for it. Meanwhile, we also introduce the
corresponding helper for warn_report().
CC: Markus Armbruster <arm...@redhat.com>
Signed-off-by: Peter Xu <pet...@redhat.com>
---
include/qemu/error-report.h | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index e1c8ae1a52..3e6e84801f 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -44,6 +44,32 @@ void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
void warn_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
void info_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
+/* Similar to error_report(), but it only prints the message once. */
+#define error_report_once(fmt, ...) \
+ ({ \
+ static bool __print_once; \
+ bool __ret_print_once = !__print_once; \
+ \
+ if (!__print_once) { \
+ __print_once = true; \
+ error_report(fmt, ##__VA_ARGS__); \
+ } \
+ unlikely(__ret_print_once); \
+ })
+
+/* Similar to warn_report(), but it only prints the message once. */
+#define warn_report_once(fmt, ...) \
+ ({ \
+ static bool __print_once; \
+ bool __ret_print_once = !__print_once; \
+ \
+ if (!__print_once) { \
+ __print_once = true; \
+ warn_report(fmt, ##__VA_ARGS__); \
+ } \
+ unlikely(__ret_print_once); \
+ })
+
const char *error_get_progname(void);
extern bool enable_timestamp_msg;
--
2.17.0
