unaligned.c   [plain text]

/*

    This program is a wrapper to assist in debugging analigned traps on the Alpha

    architectures.



    COPYRIGHT AND PERMISSION NOTICE



    Copyright (c) 2002 Sean Hunter



    Permission is hereby granted, free of charge, to any person obtaining a

    copy of this software and associated documentation files (the

    "Software"), to deal in the Software without restriction, including

    without limitation the rights to use, copy, modify, merge, publish,

    distribute, and/or sell copies of the Software, and to permit persons

    to whom the Software is furnished to do so, provided that the above

    copyright notice(s) and this permission notice appear in all copies of

    the Software and that both the above copyright notice(s) and this

    permission notice appear in supporting documentation.



    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT

    OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR

    HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL

    INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING

    FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,

    NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION

    WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.



    Except as contained in this notice, the name of a copyright holder

    shall not be used in advertising or otherwise to promote the sale, use

    or other dealings in this Software without prior written authorization

    of the copyright holder.



    --------------------------------------------------------------------------------

    All trademarks and registered trademarks mentioned herein are the property

    of their respective owners.  



*/

#include <errno.h>

#include <stdio.h>



#include <asm/sysinfo.h>

#include <asm/unistd.h>



#define TMP_PATH_MAX 1024





static int 

setsysinfo(unsigned long op, void *buffer, unsigned long size,

		      int *start, void *arg, unsigned long flag)

{

	syscall(__NR_osf_setsysinfo, op, buffer, size, start, arg, flag);

}





void 

trap_unaligned(void)

{

	unsigned int buf[2];

	buf[0] = SSIN_UACPROC;

	buf[1] = UAC_SIGBUS | UAC_NOPRINT;

	setsysinfo(SSI_NVPAIRS, buf, 1, 0, 0, 0);

}





static void 

usage(void)

{

        fprintf(stderr,

		"usage: unaligned [-b] <command-path> [command-args...]\n\n"

		"  This program is designed to assist debugging of\n"

		"  unaligned traps by running the program in gdb\n"

		"  and causing it to get SIGBUS when it encounters\n"

		"  an unaligned trap.\n\n"

		"  It is free software written by Sean Hunter <sean@uncarved.co.uk>\n"

		"  based on code by Richard Henderson and Andrew Morgan.\n\n"

	);



	exit(1);

}





int 

main(int argc, char **argv)

{

	const char my_debugger[] = "/usr/bin/gdb";



	char *temp_str;

	char *curr;

	int size = 0;

	int curr_arg;

	int isBatchMode = 0;



	/* check that we have at least 1 argument */

	if (argc < 2) {

		usage();

	}

	if( strcmp("-b" , argv[1]) == 0 ){

	    isBatchMode = 1;

	    curr_arg = 2;

        }else{

	    curr_arg = 1;

	}        



	trap_unaligned();



	if (argc > 2) {

		/* We're going to use bash process redirection to create a "file" for gdb to read

		 * containing the arguments we need */

		size = 2048;

		for(; curr_arg < argc; curr_arg++) {

			size += strlen(argv[curr_arg]);

		}

		temp_str = (char *) malloc(sizeof(char) * size);

		if (!temp_str) {

		    fprintf(stderr, "Unable to malloc memory for string use: %s\n", strerror(errno));

		    exit(255);

		}

		if(isBatchMode==1){

			sprintf(temp_str, "%s -batch %s -x <( echo file %s; echo set args", my_debugger, argv[2], argv[2]);

	        }else{

			sprintf(temp_str, "%s %s -x <( echo file %s; echo set args", my_debugger, argv[1], argv[1]);

		}

		curr = temp_str + strlen(temp_str);

		for(curr_arg = 2; curr_arg < argc; curr_arg++) {

	    		sprintf(curr, " %s", argv[curr_arg]);

			curr = temp_str + strlen(temp_str);

		}

#ifndef NOAUTORUN

		curr = temp_str + strlen(temp_str);

		sprintf(curr, "; echo run");

#endif 

		curr = temp_str + strlen(temp_str);

		sprintf(curr, ")");



		execlp("/bin/bash", "/bin/bash", "-c", temp_str, NULL);



	}

	else {

		execlp(my_debugger, my_debugger, argv[1], NULL);

	}	



	/* if we fall through to here, our exec failed -- announce the fact */

	fprintf(stderr, "Unable to execute command: %s\n", strerror(errno));



	usage();



}



/* use gcc unaligned.c -o unaliged to compile.  Add -DNOAUTORUN if you

don't want gdb to automatically run the program */