Enable handling of Litmus signals.

Add support for handling Litmus-specific signals.  Includes
framework try/catch-style handling of signals.

SIG_BUDGET is the only Litmus signal at the moment.

1 files changed, 121 insertions, 0 deletions

diff --git a/src/signal.c b/src/signal.c
new file mode 100644
index 0000000..a98ed78
--- /dev/null
+++ b/src/signal.c
@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <string.h>
+
+#include "litmus.h"
+#include "internal.h"
+
+static __thread litmus_sigjmp_t *g_sigjmp_tail = 0;
+
+void throw_litmus_signal(int signum)
+{
+        litmus_sigjmp_t *lit_env;
+
+        printf("WE GET SIGNAL!\n");
+        lit_env = pop_sigjmp();
+        if (lit_env) {
+                printf("received signal %d!\n", signum);
+                siglongjmp(lit_env->env, signum);
+        }
+        else {
+                /* silently ignore the signal. */
+        }
+}
+
+void push_sigjmp(litmus_sigjmp_t *buf)
+{
+        printf("push\n");
+        buf->prev = g_sigjmp_tail;
+        g_sigjmp_tail = buf;
+}
+
+litmus_sigjmp_t* pop_sigjmp(void)
+{
+        litmus_sigjmp_t* ret;
+        printf("pop\n");
+        ret = g_sigjmp_tail;
+        g_sigjmp_tail = (ret) ? ret->prev : NULL;
+        return ret;
+}
+
+static void reg_litmus_signals(unsigned long litmus_sig_mask,
+                struct sigaction *pAction)
+{
+        int ret;
+
+        if (litmus_sig_mask | SIG_BUDGET_MASK) { 
+                ret = sigaction(SIG_BUDGET, pAction, NULL);
+                check("SIG_BUDGET");
+        }
+        /* more ... */
+}
+
+void ignore_litmus_signals(unsigned long litmus_sig_mask)
+{
+        activate_litmus_signals(litmus_sig_mask, SIG_IGN);
+}
+
+void activate_litmus_signals(unsigned long litmus_sig_mask,
+        litmus_sig_handler_t handle)
+{
+        struct sigaction action;
+        memset(&action, 0, sizeof(action));
+        action.sa_handler = handle;
+
+        reg_litmus_signals(litmus_sig_mask, &action);
+}
+
+void activate_litmus_signal_actions(unsigned long litmus_sig_mask,
+                litmus_sig_actions_t handle)
+{
+        struct sigaction action;
+        memset(&action, 0, sizeof(action));
+        action.sa_sigaction = handle;
+        action.sa_flags = SA_SIGINFO;
+
+        reg_litmus_signals(litmus_sig_mask, &action);
+}
+
+void block_litmus_signals(unsigned long litmus_sig_mask)
+{
+        int ret;
+        sigset_t sigs;
+        sigemptyset(&sigs);
+
+        if (litmus_sig_mask | SIG_BUDGET_MASK) {
+                sigaddset(&sigs, SIG_BUDGET);
+        }
+        /* more ... */
+
+        ret = sigprocmask(SIG_BLOCK, &sigs, NULL);
+        check("SIG_BLOCK litmus signals");
+}
+
+void unblock_litmus_signals(unsigned long litmus_sig_mask)
+{
+        int ret;
+        sigset_t sigs;
+        sigemptyset(&sigs);
+
+        if (litmus_sig_mask | SIG_BUDGET_MASK) {
+                sigaddset(&sigs, SIG_BUDGET);
+        }
+        /* more ... */
+
+        ret = sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+        check("SIG_UNBLOCK litmus signals");
+}
+
+
+void longjmp_on_litmus_signal(int signum)
+{
+        litmus_sigjmp_t *lit_env;
+        printf("WE GET SIGNAL!\n");
+        lit_env = pop_sigjmp();
+        if (lit_env) {
+                printf("received signal %d\n", signum);
+                siglongjmp(lit_env->env, signum); /* restores signal mask */
+        }
+        else {
+                /* silently ignore the signal */
+        }
+}