add detach stuff

1 files changed, 87 insertions, 0 deletions

diff --git a/src/launch.c b/src/launch.c
index 942cbbb..12246de 100644
--- a/src/launch.c
+++ b/src/launch.c
@@ -14,6 +14,8 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <signal.h>
+#include <sys/wait.h>
 
 bool l2_launch__check_feature(const char *name, json_t *val, void *user);
 int l2_launch_init_substitutor(struct l2_launch *launch);
@@ -573,6 +575,84 @@ int l2_launch__find_jni(struct l2_launch *launch, char **jnifile)
   return 0;
 }
 
+volatile bool l2_launch__signal_wait = true;
+pid_t l2_launch__wait_pid = 0;
+
+void l2_launch__handle_sigusr1(int signum, siginfo_t *info, void *unk)
+{
+  L2_UNUSED(unk);
+
+  if (signum == SIGUSR1 && info->si_pid == l2_launch__wait_pid)
+    l2_launch__signal_wait = false;
+}
+
+int l2_launch__detach(void)
+{
+  pid_t childpid;
+
+  struct sigaction act;
+  memset(&act, 0, sizeof(act));
+  act.sa_sigaction = &l2_launch__handle_sigusr1;
+  act.sa_flags = SA_SIGINFO | SA_RESETHAND;
+  
+  if (sigaction(SIGUSR1, &act, NULL) < 0) {
+    CMD_ERROR("Failed to set signal action for SIGUSR1: %s", strerror(errno));
+    return -1;
+  }
+
+  if ((childpid = fork()) < 0) {
+    CMD_ERROR("Failed to fork(): %s", strerror(errno));
+    return -1;
+  } else if (!childpid) {
+    raise(SIGUSR1); /* clear signal handler */
+    return 0;
+  } else {
+    l2_launch__wait_pid = childpid;
+
+    int waitres = 0;
+    pid_t pidret;
+    while (l2_launch__signal_wait) {
+      if ((pidret = waitpid(childpid, &waitres, WNOHANG)) < 0) {
+        CMD_ERROR("Failed to wait for child %d: %s", childpid, strerror(errno));
+        return -1;
+      }
+
+      if (pidret == childpid && WIFEXITED(waitres)) {
+        CMD_ERROR("Child exited prematurely (%d)", WEXITSTATUS(waitres));
+        return -1;
+      }
+
+      pause();
+    }
+
+    CMD_INFO0("Game launched! Exiting.");
+    fflush(stderr);
+
+    _exit(0);
+  }
+}
+
+int l2_launch__detach_complete(void)
+{
+  pid_t parent = getppid();
+
+  if (setsid() == (pid_t)-1) {
+    CMD_ERROR("Failed to set SID: %s", strerror(errno));
+    return -1;
+  }
+
+  if (kill(parent, SIGUSR1) < 0) {
+    CMD_ERROR("Failed to kill parent (%d): %s", parent, strerror(errno));
+    return -1;
+  }
+
+  close(STDIN_FILENO);
+  close(STDOUT_FILENO);
+  close(STDERR_FILENO);
+
+  return 0;
+}
+
 int l2_launch_jni(struct l2_launch *launch)
 {
   int res = 0;
@@ -602,6 +682,8 @@ int l2_launch_jni(struct l2_launch *launch)
   memset(&args, 0, sizeof(JavaVMInitArgs));
   args.version = JNI_VERSION_1_8;
 
+  if (launch->detach && l2_launch__detach() < 0) return -1;
+
   char *main_class_fq;
   size_t main_class_len;
   L2_ASTRDUP(main_class_fq, main_class_len, launch->main_class);
@@ -660,6 +742,11 @@ int l2_launch_jni(struct l2_launch *launch)
     goto cleanup;
   }
 
+  if (launch->detach && l2_launch__detach_complete() < 0) {
+    res = -1;
+    goto cleanup;
+  }
+
   (*env)->CallStaticVoidMethod(env, jmaincls, main_method, jargs);
   if ((*env)->ExceptionCheck(env)) {
     (*env)->ExceptionDescribe(env);