1 files changed, 44 insertions, 0 deletions
diff --git a/keepalive.c b/keepalive.c
new file mode 100644
index 0000000..380be52
--- /dev/null
+++ b/keepalive.c
@@ -0,0 +1,44 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <time.h>
+
+const useconds_t 
+  minSleepTime = 1,
+  maxSleepTime = 1000000; 
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    fprintf(stderr, "supply a program name\n");
+    return -1;
+  }
+
+  useconds_t sleepTime = minSleepTime;
+  time_t td = time(NULL);
+  while (1) {
+    pid_t pid = fork();
+    switch (pid) {
+    case 0: // child
+      execvp(argv[1], &(argv[1]));
+      return -1; // exec failed, stop
+    case -1: // fork failed, assume temporary failure
+      break;
+    default: // parent
+      wait(NULL);
+    }
+
+    fprintf(stderr, "child exit, restarting\n");
+
+    // apply current and calc new delay
+    td = time(NULL) - td;
+    if (td > 2) {
+      sleepTime = minSleepTime;
+    }
+    usleep(sleepTime);
+    if (td <= 2) {
+      sleepTime *= 2;
+      if (sleepTime > maxSleepTime)
+	sleepTime = maxSleepTime;
+    }
+    td = time(NULL);
+  }
+}