fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / arch / um / os-Linux / main.c

diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 90912aa..685feaa 100644 (file)
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -23,6 +23,7 @@
 #include "choose-mode.h"
 #include "uml-config.h"
 #include "os.h"
+#include "um_malloc.h"
 
 /* Set in set_stklim, which is called from main and __wrap_malloc.
  * __wrap_malloc only calls it if main hasn't started.
@@ -67,13 +68,32 @@ static __init void do_uml_initcalls(void)
 
 static void last_ditch_exit(int sig)
 {
-       signal(SIGINT, SIG_DFL);
-       signal(SIGTERM, SIG_DFL);
-       signal(SIGHUP, SIG_DFL);
        uml_cleanup();
        exit(1);
 }
 
+static void install_fatal_handler(int sig)
+{
+       struct sigaction action;
+
+       /* All signals are enabled in this handler ... */
+       sigemptyset(&action.sa_mask);
+
+       /* ... including the signal being handled, plus we want the
+        * handler reset to the default behavior, so that if an exit
+        * handler is hanging for some reason, the UML will just die
+        * after this signal is sent a second time.
+        */
+       action.sa_flags = SA_RESETHAND | SA_NODEFER;
+       action.sa_restorer = NULL;
+       action.sa_handler = last_ditch_exit;
+       if(sigaction(sig, &action, NULL) < 0){
+               printf("failed to install handler for signal %d - errno = %d\n",
+                      errno);
+               exit(1);
+       }
+}
+
 #define UML_LIB_PATH   ":/usr/lib/uml"
 
 static void setup_env_path(void)
@@ -158,9 +178,12 @@ int main(int argc, char **argv, char **envp)
        }
        new_argv[argc] = NULL;
 
-       set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
-       set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
-       set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
+       /* Allow these signals to bring down a UML if all other
+        * methods of control fail.
+        */
+       install_fatal_handler(SIGINT);
+       install_fatal_handler(SIGTERM);
+       install_fatal_handler(SIGHUP);
 
        scan_elf_aux( envp);