[tor-commits] [tor/master] Add a BUG macro for usage in if checks.

[nickm at torproject.org]

commit 532820b11c9d0566b45b3dd19f01cf3e16d984ef
Author: Nick Mathewson <nickm at torproject.org>
Date:   Tue Apr 12 10:10:44 2016 -0400

    Add a BUG macro for usage in if checks.
---
 src/common/util_bug.c |  3 ++-
 src/common/util_bug.h | 14 ++++++++++++++
 src/or/connection.c   |  6 ++----
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/common/util_bug.c b/src/common/util_bug.c
index 606c665..e3e1d6d 100644
--- a/src/common/util_bug.c
+++ b/src/common/util_bug.c
@@ -26,7 +26,7 @@ tor_assertion_failed_(const char *fname, unsigned int line,
   log_backtrace(LOG_ERR, LD_BUG, buf);
 }
 
-
+/** Helper for tor_assert_nonfatal: report the assertion failure. */
 void
 tor_bug_occurred_(const char *fname, unsigned int line,
                   const char *func, const char *expr,
@@ -50,3 +50,4 @@ tor_bug_occurred_(const char *fname, unsigned int line,
   }
   log_backtrace(LOG_WARN, LD_BUG, buf);
 }
+
diff --git a/src/common/util_bug.h b/src/common/util_bug.h
index ce54266..a5f78f2 100644
--- a/src/common/util_bug.h
+++ b/src/common/util_bug.h
@@ -51,6 +51,11 @@
 /* Non-fatal bug assertions. The "unreached" variants mean "this line should
  * never be reached." The "once" variants mean "Don't log a warning more than
  * once".
+ *
+ * The 'BUG' macro checks a boolean condition and logs an error message if it
+ * is true.  Example usage:
+ *   if (BUG(x == NULL))
+ *     return -1;
  */
 
 #ifdef ALL_BUGS_ARE_FATAL
@@ -58,11 +63,16 @@
 #define tor_assert_nonfatal(cond) tor_assert((cond))
 #define tor_assert_nonfatal_unreached_once() tor_assert(0)
 #define tor_assert_nonfatal_once(cond) tor_assert((cond))
+#define BUG(cond)                                                       \
+  ((cond) ?                                                             \
+   (tor_assertion_failed_(SHORT_FILE__,__LINE__,__func__,#cond), abort(), 1) \
+   : 0)
 #elif defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS)
 #define tor_assert_nonfatal_unreached() STMT_NIL
 #define tor_assert_nonfatal(cond) ((void)(cond))
 #define tor_assert_nonfatal_unreached_once() STMT_NIL
 #define tor_assert_nonfatal_once(cond) ((void)(cond))
+#define BUG(cond) ((cond) ? 1 : 0)
 #else /* Normal case, !ALL_BUGS_ARE_FATAL, !DISABLE_ASSERTS_IN_UNIT_TESTS */
 #define tor_assert_nonfatal_unreached() STMT_BEGIN                      \
   tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 0);         \
@@ -86,6 +96,10 @@
     tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 1);      \
   }                                                                     \
   STMT_END
+#define BUG(cond)                                                       \
+  ((cond) ?                                                             \
+   (tor_bug_occurred_(SHORT_FILE__,__LINE__,__func__,#cond,0), 1)       \
+   : 0)
 #endif
 
 /** Define this if you want Tor to crash when any problem comes up,
diff --git a/src/or/connection.c b/src/or/connection.c
index 78178f9..1bd1a92 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -665,9 +665,7 @@ connection_free,(connection_t *conn))
     return;
   tor_assert(!connection_is_on_closeable_list(conn));
   tor_assert(!connection_in_array(conn));
-  if (conn->linked_conn) {
-    log_err(LD_BUG, "Called with conn->linked_conn still set.");
-    tor_fragile_assert();
+  if (BUG(conn->linked_conn)) {
     conn->linked_conn->linked_conn = NULL;
     if (! conn->linked_conn->marked_for_close &&
         conn->linked_conn->reading_from_linked_conn)
@@ -3644,7 +3642,7 @@ connection_read_to_buf(connection_t *conn, ssize_t *max_to_read,
        * take us over our read allotment, but really we shouldn't be
        * believing that SSL bytes are the same as TCP bytes anyway. */
       int r2 = read_to_buf_tls(or_conn->tls, pending, conn->inbuf);
-      if (r2<0) {
+      if (BUG(r2<0)) {
         log_warn(LD_BUG, "apparently, reading pending bytes can fail.");
         return -1;
       }