add some debugging to fd.c

Detect an invalid fd if passed to para_fd_set and abort in this case.
A typical "values of beta will cause dom!" candidate.

diff --git a/fd.c b/fd.c
index ef2c64caced7aaef2751d6fa0233e0b33346dfae..d1e0412d3f3f22174229eab26582b9a688707e85 100644 (file)
--- a/fd.c
+++ b/fd.c
@@ -64,7 +64,8 @@ int para_select(int n, fd_set *readfds, fd_set *writefds,
                err = errno;
        } while (ret < 0 && err == EINTR);
        if (ret < 0)
-               PARA_CRIT_LOG("select error (%s)\n", strerror(err));
+               PARA_CRIT_LOG("select error: %s, max_fileno: %d\n",
+                       strerror(err), n);
        return ret;
 }
 
@@ -99,6 +100,10 @@ int mark_fd_nonblock(int fd)
 */
 void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 {
+       if (fd < 0 || fd >= FD_SETSIZE) {
+               PARA_EMERG_LOG("fatal: tried to add invalid fd %d\n", fd);
+               exit(EXIT_FAILURE);
+       }
        FD_SET(fd, fds);
        *max_fileno = PARA_MAX(*max_fileno, fd);
 }