setjmp_test.c

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/*
 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

/** @file
 *
 * setjmp()/longjmp() tests
 *
 */

/* Forcibly enable assertions */
#undef NDEBUG

#include <stddef.h>
#include <assert.h>
#include <setjmp.h>
#include <ipxe/test.h>

/** A setjmp()/longjmp() test */
struct setjmp_test {
        /** Jump buffer */
        jmp_buf env;
        /** Expected value */
        int expected;
        /** Test code file */
        const char *file;
        /** Test code line */
        unsigned int line;
};

/** Expected jump */
static struct setjmp_test *jumped;

/**
 * Report a setjmp() test result
 *
 * @v test              setjmp()/longjmp() test
 *
 * This has to be implemented as a macro since if it were a function
 * then the context saved by setjmp() would be invalidated when the
 * function returned.
 */
#define setjmp_ok( test ) do {                                          \
        int value;                                                      \
        /* Sanity check */                                              \
        assert ( jumped == NULL );                                      \
        /* Initialise test */                                           \
        (test)->expected = 0;                                           \
        (test)->file = __FILE__;                                        \
        (test)->line = __LINE__;                                        \
        /* Perform setjmp() */                                          \
        value = setjmp ( (test)->env );                                 \
        /* Report setjmp()/longjmp() result */                          \
        setjmp_return_ok ( (test), value );                             \
        } while ( 0 )

/**
 * Report a setjmp()/longjmp() test result
 *
 * @v test              setjmp()/longjmp() test
 * @v value             Value returned from setjmp()
 *
 * This function ends up reporting results from either setjmp() or
 * longjmp() tests (since calls to longjmp() will return via the
 * corresponding setjmp()).  It therefore uses the test code file and
 * line stored in the test structure, which will represent the line
 * from which either setjmp() or longjmp() was called.
 */
static void setjmp_return_ok ( struct setjmp_test *test, int value ) {

        /* Determine whether this was reached via setjmp() or longjmp() */
        if ( value == 0 ) {
                /* This is the initial call to setjmp() */
                okx ( test->expected == 0, test->file, test->line );
                okx ( jumped == NULL, test->file, test->line );
        } else {
                /* This is reached via a call to longjmp() */
                okx ( value == test->expected, test->file, test->line );
                okx ( jumped == test, test->file, test->line );
        }

        /* Clear expected jump */
        jumped = NULL;
}

/**
 * Report a longjmp() test result
 *
 * @v test              setjmp()/longjmp() test
 * @v file              Test code file
 * @v line              Test code line
 */
static void __attribute__ (( noreturn ))
longjmp_okx ( struct setjmp_test *test, int value,
              const char *file, unsigned int line ) {

        /* Record expected value.  A zero passed to longjmp() should
         * result in setjmp() returning a value of one.
         */
        test->expected = ( value ? value : 1 );

        /* Record test code file and line */
        test->file = file;
        test->line = line;

        /* Record expected jump */
        jumped = test;

        /* Perform longjmp().  Should return via setjmp_okx() */
        longjmp ( test->env, value );

        /* longjmp() should never return */
        assert ( 0 );
}
#define longjmp_ok( test, value ) \
        longjmp_okx ( test, value, __FILE__, __LINE__ )

/**
 * Perform setjmp()/longjmp() self-tests
 *
 */
static void setjmp_test_exec ( void ) {
        static struct setjmp_test alpha;
        static struct setjmp_test beta;
        static int iteration;

        /* This is one of the very few situations in which the
         * "for-case" pattern is justified.
         */
        for ( iteration = 0 ; iteration < 10 ; iteration++ ) {
                DBGC ( jumped, "SETJMP test iteration %d\n", iteration );
                switch ( iteration ) {
                case 0: setjmp_ok ( &alpha ); break;
                case 1: setjmp_ok ( &beta ); break;
                case 2: longjmp_ok ( &alpha, 0 );
                case 3: longjmp_ok ( &alpha, 1 );
                case 4: longjmp_ok ( &alpha, 2 );
                case 5: longjmp_ok ( &beta, 17 );
                case 6: longjmp_ok ( &beta, 29 );
                case 7: longjmp_ok ( &alpha, -1 );
                case 8: longjmp_ok ( &beta, 0 );
                case 9: longjmp_ok ( &beta, 42 );
                }
        }
}

/** setjmp()/longjmp() self-test */
struct self_test setjmp_test __self_test = {
        .name = "setjmp",
        .exec = setjmp_test_exec,
};