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//============================================================================

//

//      assert.cxx

//

//      Host side implementation of the infrastructure assertions.

//

//============================================================================

//####COPYRIGHTBEGIN####

//                                                                          

// ----------------------------------------------------------------------------

// Copyright (C) 2002 Bart Veer

// Copyright (C) 1998, 1999, 2000, 2001 Red Hat, Inc.

//

// This file is part of the eCos host tools.

//

// This program is free software; you can redistribute it and/or modify it 

// under the terms of the GNU General Public License as published by the Free 

// Software Foundation; either version 2 of the License, or (at your option) 

// any later version.

// 

// This program 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 General Public License for 

// more details.

// 

// You should have received a copy of the GNU General Public License along with

// this program; if not, write to the Free Software Foundation, Inc., 

// 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

//

// ----------------------------------------------------------------------------

//                                                                          

//####COPYRIGHTEND####

//============================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   bartv

// Contact(s):  bartv

// Date:        1998/11/27

// Version:     0.01

// Purpose:     To provide a host-side implementation of the eCos assertion

//              facilities.

//

//####DESCRIPTIONEND####

//============================================================================

//}}}

//{{{  #include's                                       

#include "pkgconf/infra.h"

#include "cyg/infra/cyg_type.h"

// Without this symbol the header file has no effect

#define CYGDBG_USE_TRACING

// Make sure that the host-side extensions get prototyped

// as well.

#define CYG_DECLARE_HOST_ASSERTION_SUPPORT

#include "cyg/infra/cyg_ass.h"

// STDIO is needed for the default assertion handler.

// STDLIB is needed for exit() and the status codes.

#include <cstdio>

#include <cstdlib>

#if defined(__unix__) || defined(__CYGWIN32__)

extern "C" {

#include <unistd.h>             // Needed for _exit()

}

#endif

// These are needed for the table of callbacks.

#include <utility>

#include <iterator>

#include <vector>

//}}}

// -------------------------------------------------------------------------

// Statics. The host-side assertion code requires two bits of data.

//

// The first identifies the function that should actually get invoked

// when an assertion is triggered. A default implementation is defined

// in this module, but applications may install a replacement.

//

// The second is a table of callback functions that various libraries

// or bits of application code may install. Each such callback gets invoked

// when an assertion triggers.

// VC++ bogosity. Using a full function pointer prototype in a template

// confuses the compiler. It is still possible to declare the callbacks vector,

// but not any iterators for that vector. A typedef makes the problem go

// away.

typedef void (*cyg_callback_fn)(void (*)(const char*));

                                        // The current assertion handler

static bool (*current_handler)( const char*, const char*, cyg_uint32, const char*) = 0;

                                        // The callback table.

static std::vector<std::pair<const char*, cyg_callback_fn> > callbacks;

// ----------------------------------------------------------------------------

// Many applications will want to handle assertion failures differently

// from the default, for example pipe the output into an emacs buffer

// rather than just generate a file. This routine allows a suitable

// function to be installed.

extern "C" void

cyg_assert_install_failure_handler( bool(*fn)(const char*, const char*, cyg_uint32, const char*) )

{

    current_handler = fn;

}

// ----------------------------------------------------------------------------

// Various different bits of the system may want to register callback functions

// that get invoked during an assertion failure and that output useful

// data. Typically this might happen in the constructor for a static object.

// A good example of such a callback is the implementation of the trace code.

//

// The implementation requires creating a new entry in the static vector.

// A memory exhaustion exception could occur but there is no sensible way of

// handling it at this level.

//

// Multiple callbacks with the same name are legal. Multiple callbacks with

// the same function are unlikely, but it is probably not worthwhile raising

// an exception (especially since this code may be called from C).

extern "C" void

cyg_assert_install_failure_callback( const char* name, void (*fn)(void (*)(const char*)) )

{

    callbacks.push_back(std::make_pair(name, fn));

}

// -------------------------------------------------------------------------

// Once an assertion has triggered either the default handler or the

// installed handler will want to invoke all the callbacks. Rather than

// provide direct access to the callback table and require the calling

// code to be in C++, a functional interface is provided instead.

extern "C" void

cyg_assert_failure_invoke_callbacks(

    void (*first_fn)(const char*),

    void (*data_fn)(const char*),

    void (*final_fn)(void) )

{

    std::vector<std::pair<const char*, cyg_callback_fn> >::const_iterator i;

    for ( i = callbacks.begin(); i != callbacks.end(); i++ ) {

        if (0 != first_fn) {

            (*first_fn)(i->first);

        }

        if (0 != data_fn) {

            (*(i->second))(data_fn);

        }

        if (0 != final_fn) {

            (*final_fn)();

        }

    }

}

// ----------------------------------------------------------------------------

// The default assertion handler. This assumes that the application is 

// a console application with a sensible stderr stream.

//

// First some initial diagnostics are output immediately, in case

// subsequent attempts to output more data cause additional failures. It

// is worthwhile detecting recursive assertion failures.

//

// Assuming the table of callbacks is not empty it is possible to

// output some more data to a file. If possible mkstemp() is used to

// create this file. If mkstemp() is not available then tmpnam() is

// used instead. That function has security problems, albeit not ones

// likely to affect dump files. Once the file is opened the callbacks

// are invoked. Three utilities have to be provided to do the real

// work, and a static is used to keep track of the FILE * pointer.

//

// The testcase tassert8, and in particular the associated Tcl proc

// tassert8_filter in testsuite/cyginfra/assert.exp, has detailed

// knowledge of the output format. Any changes here may need to be

// reflected in that test case. There are also support routines in

// hosttest.exp which may need to be updated.

static FILE * default_handler_output_file = 0;

static bool   body_contains_data          = false;

                                        // output the callback name

static void

default_handler_first_fn(const char* name)

{

    if (0 != default_handler_output_file) {

        fprintf(default_handler_output_file, "# {{{  %s\n\n", name);

    }

    body_contains_data = false;

}

                                        // output some actual text.

static void

default_handler_second_fn(const char* data)

{

    body_contains_data = true;

    if (0 != default_handler_output_file) {

        fputs(data, default_handler_output_file);

    }

}

                                        // the end of a callback.

static void

default_handler_final_fn( void )

{

    if (0 != default_handler_output_file) {

        if (body_contains_data) {

            fputs("\n", default_handler_output_file);

        }

        fputs("# }}}\n", default_handler_output_file);

    }

}

static void

default_handler(const char* fn, const char* file, cyg_uint32 lineno, const char* msg)

{

    static int invoke_count = 0;

    if (2 == invoke_count) {

        // The fprintf() immediately below causes an assertion failure

    } else if (1 == invoke_count) {

        invoke_count++;

        fprintf(stderr, "Recursive assertion failure.\n");

        return;

    } else {

        invoke_count = 1;

    }

    // There is an argument for using write() rather than fprintf() here,

    // in case the C library has been corrupted. For now this has not been

    // attempted.

    if (0 == msg)

        msg ="<unknown>";

    if (0 == file)

        file = "<unknown>";

    fprintf(stderr, "Assertion failure: %s\n", msg);

    fprintf(stderr, "File %s, line number %lu\n", file, (unsigned long) lineno);

    if (0 != fn)

        fprintf(stderr, "Function %s\n", fn);

    // Only create a logfile if more information is available.

    if (0 != callbacks.size() ) {

        // Use mkstemp() if possible, but only when running on a platform where /tmp

        // is likely to be available.

#if defined(HAVE_MKSTEMP) && !defined(_MSC_VER)

        char filename[32];

        int  fd;

        strcpy(filename, "/tmp/ecosdump.XXXXXX");

        fd = mkstemp(filename);

        if (-1 == fd) {

            fprintf(stderr, "Unable to create a suitable output file for additional data.\n");

        } else {

            default_handler_output_file = fdopen(fd, "w");

            if (0 == default_handler_output_file) {

                close(fd);

            }

        }

#else

        char filename[L_tmpnam];

        if (0 == tmpnam(filename)) {

            fprintf(stderr, "Unable to create a suitable output file for additional data.\n");

        } else {

            // No attempt is made to ensure that the file does not already

            // exist. This would require POSIX calls rather than ISO C ones.

            // The probability of a problem is considered to be too small

            // to worry about.

            default_handler_output_file = fopen(filename, "w");

        }

#endif

        if (0 == default_handler_output_file) {

            fprintf(stderr, "Unable to open output file %s\n", filename);

            fputs("No further assertion information is available.\n", stderr);

        } else {

            fprintf(stderr, "Writing additional output to %s\n", filename);

            // Repeat the information about the assertion itself.

            fprintf(default_handler_output_file, "Assertion failure: %s\n", msg);

            fprintf(default_handler_output_file, "File %s, line number %lu\n", file, (unsigned long) lineno);

            if (0 != fn)

                fprintf(default_handler_output_file, "Function %s\n", fn);

            fputs("\n", default_handler_output_file);

            // Now for the various callbacks.

            cyg_assert_failure_invoke_callbacks( &default_handler_first_fn,

                                                 &default_handler_second_fn, &default_handler_final_fn );

            // And close the file.

            fputs("\nEnd of assertion data.\n", default_handler_output_file);

            fclose(default_handler_output_file);

        }

    }

    fflush(stderr);

}

// ----------------------------------------------------------------------------

// The assertion handler. This is the function that gets invoked when

// an assertion triggers. If a special assertion handler has been installed

// then this gets called. If it returns false or if no special handler is

// available then the default handler gets called instead. Typically the

// user will now have a lot of information about what happened to cause the

// assertion failure. The next stage is to invoke abort() which should

// terminate the program and generate a core dump for subsequent inspection

// (unless of course the application is already running in a debugger session).

// A final call to _exit() should be completely redundant.

extern "C" void

cyg_assert_fail( const char* fn, const char* file, cyg_uint32 lineno, const char* msg )

{

    if ((0 == current_handler) || !(*current_handler)(fn, file, lineno, msg)) {

        default_handler(fn, file, lineno, msg);

    }

    abort();

    _exit(0);

}

// ----------------------------------------------------------------------------

// A utility function, primarily intended to be called from inside gdb.

extern "C" void

cyg_assert_quickfail(void)

{

    cyg_assert_fail("gdb", "<no file>", 0, "manual call");

}