CONTRIB: tcploop: add basic loops via a jump instruction

This one jumps back to the oldest post-fork and post-accept action,
so it allows to recv(), pause() and send() in loops after a fork()
and an accept() for example. This is handy for bugs that reproduce
once in a while or to keep idle connections working.

diff --git a/contrib/tcploop/tcploop.c b/contrib/tcploop/tcploop.c
index 9429aff0d5a8fe01bb74549279cbfcc1ba80848f..a2ab59e76e42a8ae4412b515f6789eb2ebd2ed95 100644 (file)
--- a/contrib/tcploop/tcploop.c
+++ b/contrib/tcploop/tcploop.c
@@ -99,6 +99,7 @@ __attribute__((noreturn)) void usage(int code, const char *arg0)
            "                 Note: fd=socket,connect(fd)\n"
            "  A[<count>]   : Accepts <count> incoming sockets and closes count-1\n"
            "                 Note: fd=accept(fd)\n"
+           "  J            : Jump back to oldest post-fork/post-accept action\n"
            "  G            : disable lingering\n"
            "  T            : set TCP_NODELAY\n"
            "  Q            : disable TCP Quick-ack\n"
@@ -705,6 +706,7 @@ int main(int argc, char **argv)
        struct sockaddr_storage ss;
        struct err_msg err;
        const char *arg0;
+       int loop_arg;
        int arg;
        int ret;
        int sock;
@@ -739,7 +741,8 @@ int main(int argc, char **argv)
        gettimeofday(&start_time, NULL);
 
        sock = -1;
-       for (arg = 2; arg < argc; arg++) {
+       loop_arg = 2;
+       for (arg = loop_arg; arg < argc; arg++) {
                switch (argv[arg][0]) {
                case 'L':
                        /* silently ignore existing connections */
@@ -765,6 +768,7 @@ int main(int argc, char **argv)
                        if (sock < 0)
                                die(1, "Fatal: tcp_accept() failed.\n");
                        dolog("accept\n");
+                       loop_arg = arg + 1; // cannot loop before accept()
                        break;
 
                case 'T':
@@ -866,12 +870,18 @@ int main(int argc, char **argv)
                                die(1, "Fatal: fork() failed.\n");
                        if (ret > 0) {
                                /* loop back to first arg */
-                               arg = 1;
+                               arg = loop_arg - 1;
                                continue;
                        }
                        /* OK we're in the child, let's continue */
                        pid = getpid();
+                       loop_arg = arg + 1;
                        break;
+
+               case 'J': // jump back to oldest post-fork action
+                       arg = loop_arg - 1;
+                       continue;
+
                default:
                        usage(1, arg0);
                }