guile/libguile/error.c

/* Copyright 1995-1998,2000-2001,2004,2006,2010,2012-2014,2018
     Free Software Foundation, Inc.

   This file is part of Guile.

   Guile is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Guile is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
   License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with Guile.  If not, see
   <https://www.gnu.org/licenses/>.  */




#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/* For Windows... */
#ifdef HAVE_IO_H
#include <io.h>
#endif

#include "async.h"
#include "dynwind.h"
#include "gsubr.h"
#include "list.h"
#include "modules.h"
#include "numbers.h"
#include "pairs.h"
#include "strings.h"
#include "symbols.h"
#include "throw.h"

#include "error.h"




/* {Errors and Exceptional Conditions}
 */


/* Scheme interface to scm_error_scm.  */
void
scm_error (SCM key, const char *subr, const char *message, SCM args, SCM rest)
{
  scm_error_scm 
    (key,
     (subr == NULL) ? SCM_BOOL_F : scm_from_locale_string (subr),
     (message == NULL) ? SCM_BOOL_F : scm_from_locale_string (message),
     args, rest);
}

/* All errors should pass through here.  */
SCM_DEFINE (scm_error_scm, "scm-error", 5, 0, 0, 
           (SCM key, SCM subr, SCM message, SCM args, SCM data),
	    "Raise an error with key @var{key}.  @var{subr} can be a string\n"
	    "naming the procedure associated with the error, or @code{#f}.\n"
	    "@var{message} is the error message string, possibly containing\n"
	    "@code{~S} and @code{~A} escapes.  When an error is reported,\n"
	    "these are replaced by formatting the corresponding members of\n"
	    "@var{args}: @code{~A} (was @code{%s} in older versions of\n"
	    "Guile) formats using @code{display} and @code{~S} (was\n"
	    "@code{%S}) formats using @code{write}.  @var{data} is a list or\n"
	    "@code{#f} depending on @var{key}: if @var{key} is\n"
	    "@code{system-error} then it should be a list containing the\n"
	    "Unix @code{errno} value; If @var{key} is @code{signal} then it\n"
	    "should be a list containing the Unix signal number; If\n"
	    "@var{key} is @code{out-of-range}, @code{wrong-type-arg},\n"
	    "or @code{keyword-argument-error}, "
            "it is a list containing the bad value; otherwise\n"
	    "it will usually be @code{#f}.")
#define FUNC_NAME s_scm_error_scm
{
  scm_ithrow (key, scm_list_4 (subr, message, args, data), 1);
  
  /* No return, but just in case: */
  fprintf (stderr, "Guile scm_ithrow returned!\n");
  exit (EXIT_FAILURE);
}
#undef FUNC_NAME

/* strerror may not be thread safe, for instance in glibc (version 2.3.2) an
   error number not among the known values results in a string like "Unknown
   error 9999" formed in a static buffer, which will be overwritten by a
   similar call in another thread.  A test program running two threads with
   different unknown error numbers can trip this fairly quickly.

   Some systems don't do what glibc does, instead just giving a single
   "Unknown error" for unrecognised numbers.  It doesn't seem worth trying
   to tell if that's the case, a mutex is reasonably fast, and strerror
   isn't needed very often.

   strerror_r (when available) could be used, it might be a touch faster
   than a frame and a mutex, though there's probably not much
   difference.  */

SCM_DEFINE (scm_strerror, "strerror", 1, 0, 0, 
            (SCM err),
	    "Return the Unix error message corresponding to @var{err}, which\n"
	    "must be an integer value.")
#define FUNC_NAME s_scm_strerror
{
  SCM ret;
  int errnum = scm_to_int (err);  /* Must be done outside of the
				     critical section below, to avoid a
				     deadlock on errors.  */
  scm_dynwind_begin (0);
  scm_i_dynwind_pthread_mutex_lock (&scm_i_misc_mutex);

  ret = scm_from_locale_string (strerror (errnum));

  scm_dynwind_end ();
  return ret;
}
#undef FUNC_NAME

SCM_GLOBAL_SYMBOL (scm_system_error_key, "system-error");
void
scm_syserror (const char *subr)
{
  SCM err = scm_from_int (errno);

  /* It could be that we're getting here because the syscall was
     interrupted by a signal.  In that case a signal handler might have
     been queued to run.  The signal handler probably throws an
     exception.

     If we don't try to run the signal handler now, it will run later,
     which would result in two exceptions being thrown: this syserror,
     and then at some later time the exception thrown by the async
     signal handler.

     The problem is that we don't know if handling the signal caused an
     async to be queued.  By this time scmsigs.c:take_signal will have
     written a byte on the fd, but we don't know if the signal-handling
     thread has read it off and queued an async.

     Ideally we need some API like scm_i_ensure_signals_delivered() to
     catch up signal delivery.  Barring that, we just cross our digits
     and pray; it could be that we handle the signal in time, and just
     throw once, or it could be that we miss the deadline and throw
     twice.
  */
#ifdef EINTR
  if (scm_to_int (err) == EINTR)
    scm_async_tick ();
#endif

  scm_error (scm_system_error_key,
	     subr,
	     "~A",
	     scm_cons (scm_strerror (err), SCM_EOL),
	     scm_cons (err, SCM_EOL));
}

void
scm_syserror_msg (const char *subr, const char *message, SCM args, int eno)
{
  /* See above note about the EINTR signal handling race. */
#ifdef EINTR
  if (eno == EINTR)
    scm_async_tick ();
#endif
  scm_error (scm_system_error_key,
	     subr,
	     message,
	     args,
	     scm_cons (scm_from_int (eno), SCM_EOL));
}

SCM_GLOBAL_SYMBOL (scm_num_overflow_key, "numerical-overflow");
void
scm_num_overflow (const char *subr)
{
  scm_error (scm_num_overflow_key,
	     subr,
	     "Numerical overflow",
	     SCM_BOOL_F,
	     SCM_BOOL_F);
}

SCM_GLOBAL_SYMBOL (scm_out_of_range_key, "out-of-range");
void
scm_out_of_range (const char *subr, SCM bad_value)
{
  scm_error (scm_out_of_range_key,
	     subr,
	     "Value out of range: ~S",
             scm_list_1 (bad_value),
             scm_list_1 (bad_value));
}

void
scm_out_of_range_pos (const char *subr, SCM bad_value, SCM pos)
{
  scm_error (scm_out_of_range_key,
	     subr,
	     "Argument ~A out of range: ~S",
             scm_list_2 (pos, bad_value),
	     scm_list_1 (bad_value));
}


SCM_GLOBAL_SYMBOL (scm_args_number_key, "wrong-number-of-args");
void
scm_wrong_num_args (SCM proc)
{
  scm_error (scm_args_number_key,
	     NULL,
	     "Wrong number of arguments to ~A",
	     scm_list_1 (proc),
	     SCM_BOOL_F);
}


void
scm_error_num_args_subr (const char *subr)
{
  scm_error (scm_args_number_key,
	     NULL,
	     "Wrong number of arguments to ~A",
	     scm_list_1 (scm_from_locale_string (subr)),
	     SCM_BOOL_F);
}


SCM_GLOBAL_SYMBOL (scm_arg_type_key, "wrong-type-arg");
void
scm_wrong_type_arg (const char *subr, int pos, SCM bad_value)
{
  scm_error (scm_arg_type_key,
	     subr,
	     (pos == 0) ? "Wrong type: ~S"
	     : "Wrong type argument in position ~A: ~S",
	     (pos == 0) ? scm_list_1 (bad_value)
	     : scm_list_2 (scm_from_int (pos), bad_value),
	     scm_list_1 (bad_value));
}

void
scm_i_wrong_type_arg_symbol (SCM symbol, int pos, SCM bad_value)
{
  scm_error_scm (scm_arg_type_key,
		 scm_symbol_to_string (symbol),
		 (pos == 0) ? scm_from_locale_string ("Wrong type: ~S")
		 : scm_from_locale_string ("Wrong type argument in position ~A: ~S"),
		 (pos == 0) ? scm_list_1 (bad_value)
		 : scm_list_2 (scm_from_int (pos), bad_value),
		 scm_list_1 (bad_value));
  scm_remember_upto_here_2 (symbol, bad_value);
}

void
scm_wrong_type_arg_msg (const char *subr, int pos, SCM bad_value, const char *szMessage)
{
  SCM msg = scm_from_locale_string (szMessage);
  if (pos == 0)
    {
      scm_error (scm_arg_type_key,
		 subr, "Wrong type (expecting ~A): ~S",
		 scm_list_2 (msg, bad_value),
		 scm_list_1 (bad_value));
    }
  else
    {
      scm_error (scm_arg_type_key,
		 subr,
		 "Wrong type argument in position ~A (expecting ~A): ~S",
		 scm_list_3 (scm_from_int (pos), msg, bad_value),
		 scm_list_1 (bad_value));
    }
}


SCM_GLOBAL_SYMBOL (scm_misc_error_key, "misc-error");
void
scm_misc_error (const char *subr, const char *message, SCM args)
{
  scm_error (scm_misc_error_key, subr, message, args, SCM_BOOL_F);
}

void
scm_init_error ()
{
#include "cpp-E.c"
#include "error.x"
}