vm: interrupt stdin_loop when entering fep

The stdin_loop thread will keep trying to consume input unless we stop it by sending it a signal. Use SIGUSR2 to stop the read syscall and a mutex to hold up the loop while the fep is active.

diff --git a/vm/debug.cpp b/vm/debug.cpp
index 52db681f416553acb3b878d56ab9543ab57e0db7..a10e323184550db7a8f813bfb670720a70c6677d 100755 (executable)
--- a/vm/debug.cpp
+++ b/vm/debug.cpp
@@ -438,6 +438,12 @@ void factor_vm::factorbug_usage(bool advanced_p)
 
 }
 
+static void exit_fep(factor_vm *vm)
+{
+       vm->unlock_console();
+       vm->fep_p = false;
+}
+
 void factor_vm::factorbug()
 {
        if(fep_disabled)
@@ -452,6 +458,9 @@ void factor_vm::factorbug()
        fep_p = true;
 
        std::cout << "Starting low level debugger..." << std::endl;
+
+       lock_console();
+
        if (!fep_help_was_shown) {
                factorbug_usage(false);
                fep_help_was_shown = true;
@@ -530,12 +539,12 @@ void factor_vm::factorbug()
                        dump_generations();
                else if(strcmp(cmd,"c") == 0)
                {
-                       fep_p = false;
+                       exit_fep(this);
                        return;
                }
                else if(strcmp(cmd,"t") == 0)
                {
-                       fep_p = false;
+                       exit_fep(this);
                        general_error(ERROR_INTERRUPT,false_object,false_object);
                        assert(false);
                }

diff --git a/vm/os-unix.cpp b/vm/os-unix.cpp
index 75774d00c62fdf8116a8d6895aebb302916f4cae..54ac9ab25839e7a6e94964ae9c51ea7e274305f3 100755 (executable)
--- a/vm/os-unix.cpp
+++ b/vm/os-unix.cpp
@@ -317,8 +317,6 @@ void factor_vm::unix_init_signals()
        sigaction_safe(SIGABRT,&synchronous_sigaction,NULL);
 
        init_sigaction_with_handler(&enqueue_sigaction, enqueue_signal_handler);
-       sigaction_safe(SIGUSR1,&enqueue_sigaction,NULL);
-       sigaction_safe(SIGUSR2,&enqueue_sigaction,NULL);
        sigaction_safe(SIGWINCH,&enqueue_sigaction,NULL);
 #ifdef SIGINFO
        sigaction_safe(SIGINFO,&enqueue_sigaction,NULL);
@@ -336,6 +334,8 @@ void factor_vm::unix_init_signals()
        io.launcher.unix for this. */
        init_sigaction_with_handler(&ignore_sigaction, ignore_signal_handler);
        sigaction_safe(SIGPIPE,&ignore_sigaction,NULL);
+       /* We send SIGUSR2 to the stdin_loop thread to interrupt it on FEP */
+       sigaction_safe(SIGUSR2,&ignore_sigaction,NULL);
 }
 
 /* On Unix, shared fds such as stdin cannot be set to non-blocking mode
@@ -355,6 +355,9 @@ extern "C" {
 
        int size_read;
        int size_write;
+
+       THREADHANDLE stdin_thread;
+       pthread_mutex_t stdin_mutex;
 }
 
 void safe_close(int fd)
@@ -404,13 +407,18 @@ void *stdin_loop(void *arg)
        unsigned char buf[4096];
        bool loop_running = true;
 
+       // If we fep, the parent thread will grab a mutex and send us SIGUSR2 to make
+       // us relinquish our hold on stdin.
        sigset_t mask;
        sigfillset(&mask);
-       pthread_sigmask(SIG_BLOCK, &mask, NULL);
+       sigdelset(&mask, SIGUSR2);
+       pthread_sigmask(SIG_SETMASK, &mask, NULL);
 
        while(loop_running)
        {
-               if(!safe_read(control_read,buf,1))
+               bool readp = safe_read(control_read,buf,1);
+
+               if(!readp)
                        break;
 
                if(buf[0] != 'X')
@@ -418,6 +426,8 @@ void *stdin_loop(void *arg)
 
                for(;;)
                {
+                       pthread_mutex_lock(&stdin_mutex);
+                       pthread_mutex_unlock(&stdin_mutex);
                        ssize_t bytes = read(0,buf,sizeof(buf));
                        if(bytes < 0)
                        {
@@ -446,12 +456,24 @@ void *stdin_loop(void *arg)
        return NULL;
 }
 
-void open_console()
+void factor_vm::open_console()
 {
        safe_pipe(&control_read,&control_write);
        safe_pipe(&size_read,&size_write);
        safe_pipe(&stdin_read,&stdin_write);
-       start_thread(stdin_loop,NULL);
+       stdin_thread = start_thread(stdin_loop,NULL);
+       pthread_mutex_init(&stdin_mutex, NULL);
+}
+
+void factor_vm::lock_console()
+{
+       pthread_mutex_lock(&stdin_mutex);
+       pthread_kill(stdin_thread, SIGUSR2);
+}
+
+void factor_vm::unlock_console()
+{
+       pthread_mutex_unlock(&stdin_mutex);
 }
 
 }

diff --git a/vm/os-unix.hpp b/vm/os-unix.hpp
index a64b8f0e08600fe05fa6c2e79c9cfae80eb8d84e..c0cce24a06765a42ca32bc3a903385fe5f50f256 100644 (file)
--- a/vm/os-unix.hpp
+++ b/vm/os-unix.hpp
@@ -9,6 +9,7 @@
 #include <dlfcn.h>
 #include <signal.h>
 #include <pthread.h>
+#include <sched.h>
 
 #include "atomic-gcc.hpp"
 
@@ -41,7 +42,6 @@ inline static THREADHANDLE thread_id() { return pthread_self(); }
 
 u64 nano_count();
 void sleep_nanos(u64 nsec);
-void open_console();
 
 void move_file(const vm_char *path1, const vm_char *path2);
 

diff --git a/vm/os-windows.cpp b/vm/os-windows.cpp
index 0661b33e7177c097e0db9943375569b69aae53c2..4b4b4e78c3514741d2d800a9421593d95c721b23 100755 (executable)
--- a/vm/os-windows.cpp
+++ b/vm/os-windows.cpp
@@ -301,6 +301,14 @@ void factor_vm::open_console()
        SetConsoleCtrlHandler(factor::ctrl_handler, TRUE);
 }
 
+void factor_vm::lock_console()
+{
+}
+
+void factor_vm::unlock_console()
+{
+}
+
 void factor_vm::sampler_thread_loop()
 {
        LARGE_INTEGER counter, new_counter, units_per_second;

diff --git a/vm/vm.hpp b/vm/vm.hpp
index 25e8a334375a0c55e5a2165edd9fc7f002a88c5f..a4c11e390f6fb0f259ebe4211133dd7962df3db0 100755 (executable)
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -736,6 +736,9 @@ struct factor_vm
        void init_signals();
        void start_sampling_profiler_timer();
        void end_sampling_profiler_timer();
+       void open_console();
+       void lock_console();
+       void unlock_console();
 
        // os-windows
   #if defined(WINDOWS)
@@ -747,7 +750,6 @@ struct factor_vm
        void windows_image_path(vm_char *full_path, vm_char *temp_path, unsigned int length);
        BOOL windows_stat(vm_char *path);
 
-       void open_console();
        LONG exception_handler(PEXCEPTION_RECORD e, void *frame, PCONTEXT c, void *dispatch);
 
   #else  // UNIX