src/runtime/interrupt.h

   1 /*
   2  * This software is part of the SBCL system. See the README file for
   3  * more information.
   4  *
   5  * This software is derived from the CMU CL system, which was
   6  * written at Carnegie Mellon University and released into the
   7  * public domain. The software is in the public domain and is
   8  * provided with absolutely no warranty. See the COPYING and CREDITS
   9  * files for more information.
  10  */
  11
  12 #if !defined(_INCLUDE_INTERRUPT_H_)
  13 #define _INCLUDE_INTERRUPT_H_
  14
  15 #include <signal.h>
  16 #include <string.h>
  17
  18 /*
  19  * This is a workaround for some slightly silly Linux/GNU Libc
  20  * behaviour: glibc defines sigset_t to support 1024 signals, which is
  21  * more than the kernel.  This is usually not a problem, but becomes
  22  * one when we want to save a signal mask from a ucontext, and restore
  23  * it later into another ucontext: the ucontext is allocated on the
  24  * stack by the kernel, so copying a libc-sized sigset_t into it will
  25  * overflow and cause other data on the stack to be corrupted */
  26 /* FIXME: do not rely on NSIG being a multiple of 8 */
  27 #define REAL_SIGSET_SIZE_BYTES ((NSIG/8))
  28
  29 /* Set all deferrable signals into *s. */
  30 extern void sigaddset_deferrable(sigset_t *s);
  31 /* Set all blockable signals into *s. */
  32 extern void sigaddset_blockable(sigset_t *s);
  33 /* Set all gc signals into *s. */
  34 extern void sigaddset_gc(sigset_t *s);
  35
  36 extern sigset_t deferrable_sigset;
  37 extern sigset_t blockable_sigset;
  38 extern sigset_t gc_sigset;
  39
  40 extern void block_deferrable_signals(void);
  41 extern void block_blockable_signals(void);
  42 extern void unblock_deferrable_signals(void);
  43 extern void unblock_gc_signals(void);
  44 extern void unblock_signals_in_context_and_maybe_warn(os_context_t *context);
  45
  46 extern void check_deferrables_blocked_or_lose(void);
  47 extern void check_blockables_blocked_or_lose(void);
  48 extern void check_gc_signals_unblocked_or_lose(void);
  49 extern void check_gc_signals_unblocked_in_sigset_or_lose(sigset_t *sigset);
  50
  51 extern void maybe_save_gc_mask_and_block_deferrables(sigset_t *sigset);
  52
  53 static inline void
  54 sigcopyset(sigset_t *new, sigset_t *old)
  55 {
  56     memcpy(new, old, REAL_SIGSET_SIZE_BYTES);
  57 }
  58
  59 /* maximum signal nesting depth
  60  *
  61  * FIXME: In CMUCL this was 4096, and it was first scaled down to 256
  62  * and then 32, until finally Stumpwm broke: it is possible to receive
  63  * interrupts in sufficiently quick succession that handler nesting
  64  * can become preposterous. Scaling this back up to 1024 is a bandaid:
  65  * for a real fix we should consider the following things:
  66  *
  67  *   We should almost certainly always use
  68  *   arrange_return_to_lisp_function, though it needs to be thought
  69  *   about arguments, and it needs to be able to pass a frobbable
  70  *   context to the callee...
  71  *
  72  *   There are cases when nesting handlers is exactly what we want:
  73  *   eg. SIGINT.
  74  *
  75  *   There are cases when we probably want to drop duplicate signals
  76  *   on the floor if they arrive before the previous one has been handled.
  77  *   Eg. SIGPROF.
  78  *
  79  *   There are cases when we probably want to handle duplicate signals
  80  *   after the previous handler has returned, not before. Eg. SIGALARM.
  81  *
  82  * -- NS 2007-01-29
  83  */
  84 #define MAX_INTERRUPTS 1024
  85
  86 union interrupt_handler {
  87     lispobj lisp;
  88     void (*c)(int, siginfo_t*, void*);
  89 };
  90
  91 extern union interrupt_handler interrupt_handlers[NSIG];
  92
  93 struct interrupt_data {
  94     /* signal information for pending signal.  pending_signal=0 when there
  95      * is no pending signal. */
  96     void (*pending_handler) (int, siginfo_t*, void*) ;
  97     int pending_signal;
  98     siginfo_t pending_info;
  99     sigset_t pending_mask;
 100     /* Was pending mask saved for gc request? True if GC_PENDING or
 101      * SIG_STOP_FOR_GC happened in a pseudo atomic with no GC_INHIBIT
 102      * NIL. Both deferrable interrupt handlers and gc are careful not
 103      * to clobber each other's pending_mask. */
 104     boolean gc_blocked_deferrables;
 105 };
 106
 107 extern boolean interrupt_handler_pending_p(void);
 108 extern void interrupt_init(void);
 109 extern void fake_foreign_function_call(os_context_t* context);
 110 extern void undo_fake_foreign_function_call(os_context_t* context);
 111 extern void arrange_return_to_lisp_function(os_context_t *, lispobj);
 112 extern void interrupt_handle_now(int, siginfo_t*, os_context_t*);
 113 extern void interrupt_handle_pending(os_context_t*);
 114 extern void interrupt_internal_error(os_context_t*, boolean continuable);
 115 extern boolean handle_guard_page_triggered(os_context_t *,os_vm_address_t);
 116 extern boolean maybe_defer_handler(void *handler, struct interrupt_data *data,
 117                                    int signal, siginfo_t *info,
 118                                    os_context_t *context);
 119 #if defined LISP_FEATURE_GENCGC
 120 /* assembly language stub that executes trap_PendingInterrupt */
 121 extern void do_pending_interrupt(void);
 122 #endif
 123
 124 #ifdef LISP_FEATURE_SB_THREAD
 125 extern void interrupt_thread_handler(int, siginfo_t*, void*);
 126 extern void sig_stop_for_gc_handler(int, siginfo_t*, void*);
 127 #endif
 128 typedef void (*interrupt_handler_t)(int, siginfo_t *, void *);
 129 extern void undoably_install_low_level_interrupt_handler (
 130                         int signal,
 131                         interrupt_handler_t handler);
 132 extern unsigned long install_handler(int signal,
 133                                      interrupt_handler_t handler);
 134
 135 extern union interrupt_handler interrupt_handlers[NSIG];
 136
 137 /* The void* casting here avoids having to mess with the various types
 138  * of function argument lists possible for signal handlers:
 139  * SA_SIGACTION handlers have one signature, and the default old-style
 140  * signal(..) handlers have another, and attempting to represent them
 141  * "cleanly" with union types is in fact a mess. */
 142 #define ARE_SAME_HANDLER(x, y) ((void*)(x) == (void*)(y))
 143
 144 extern void handle_trap(os_context_t *context, int trap);
 145
 146 #ifndef LISP_FEATURE_WIN32
 147 extern void lisp_memory_fault_error(os_context_t *context,
 148                                     os_vm_address_t addr);
 149 #endif
 150
 151 #endif