+
+/* Install the handler FUNC for signal SIG, and return the previous
+ handler. */
+handler_t
+rpl_signal (int sig, handler_t handler)
+{
+ /* We must provide a wrapper, so that a user can query what handler
+ they installed even if that signal is currently blocked. */
+ if (sig >= 0 && sig < NSIG && sig != SIGKILL && sig != SIGSTOP
+ && handler != SIG_ERR)
+ {
+ #ifdef SIGABRT_COMPAT
+ if (sig == SIGABRT_COMPAT)
+ sig = SIGABRT;
+ #endif
+
+ if (blocked_set & (1U << sig))
+ {
+ /* POSIX states that sigprocmask and signal are both
+ async-signal-safe. This is not true of our
+ implementation - there is a slight data race where an
+ asynchronous interrupt on signal A can occur after we
+ install blocked_handler but before we have updated
+ old_handlers for signal B, such that handler A can see
+ stale information if it calls signal(B). Oh well -
+ signal handlers really shouldn't try to manipulate the
+ installed handlers of unrelated signals. */
+ handler_t result = old_handlers[sig];
+ old_handlers[sig] = handler;
+ return result;
+ }
+ else
+ return signal (sig, handler);
+ }
+ else
+ {
+ errno = EINVAL;
+ return SIG_ERR;
+ }
+}
+
+#if GNULIB_defined_SIGPIPE
+/* Raise the signal SIG. */
+int
+rpl_raise (int sig)
+# undef raise
+{
+ switch (sig)
+ {
+ case SIGPIPE:
+ if (blocked_set & (1U << sig))
+ pending_array[sig] = 1;
+ else
+ {
+ handler_t handler = SIGPIPE_handler;
+ if (handler == SIG_DFL)
+ exit (128 + SIGPIPE);
+ else if (handler != SIG_IGN)
+ (*handler) (sig);
+ }
+ return 0;
+ default: /* System defined signal */
+ return raise (sig);
+ }
+}
+#endif