sys/kern/shell_imgact.c

/*
 * Copyright (c) 1993, David Greenman
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by David Greenman
 * 4. The name of the developer may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      $Id: shell_imgact.c,v 1.3 1993/12/11 06:55:33 davidg Exp davidg $
 */

#include "param.h"
#include "systm.h"
#include "resourcevar.h"
#include "imgact.h"

#define SHELLMAGIC      0x2123 /* #! */
#define MAXSHELLCMDLEN  64

/*
 * Shell interpreter image activator. A interpreter name beginning
 *      at iparams->stringbase is the minimal successful exit requirement.
 */
int
exec_shell_imgact(iparams)
        struct image_params *iparams;
{
        const char *image_header = iparams->image_header;
        const char *ihp, *line_endp;
        int length;
        char *interp;
        char **argv;

        /* a shell script? */
        if (((short *) image_header)[0] != SHELLMAGIC)
                return(-1);

        /*
         * Don't allow a shell script to be the shell for a shell
         *      script. :-)
         */
        if (iparams->interpreted)
                return(ENOEXEC);

        iparams->interpreted = 1;

        /*
         * Copy shell name and arguments from image_header into string
         *      buffer.
         */

        /*
         * Find end of line; return if the line > MAXSHELLCMDLEN long.
         */
        for (ihp = &image_header[2]; *ihp != '\n'; ++ihp) {
                if (ihp >= &image_header[MAXSHELLCMDLEN])
                        return(ENOEXEC);
        }
        line_endp = ihp;

        /* reset for another pass */
        ihp = &image_header[2];

        /* Skip over leading spaces - until the interpreter name */
        while ((*ihp == ' ') || (*ihp == '\t')) ihp++;

        /* copy the interpreter name */
        interp = iparams->interpreter_name;
        while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t'))
                *interp++ = *ihp++;
        *interp = '\0';

        /* Disallow a null interpreter filename */
        if (*iparams->interpreter_name == '\0')
                return(ENOEXEC);

        /* reset for another pass */
        ihp = &image_header[2];

        /* copy the interpreter name and arguments */
        while (ihp < line_endp) {
                /* Skip over leading spaces */
                while ((*ihp == ' ') || (*ihp == '\t')) ihp++;

                if (ihp < line_endp) {
                        /*
                         * Copy to end of token. No need to watch stringspace
                         *      because this is at the front of the string buffer
                         *      and the maximum shell command length is tiny.
                         */
                        while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) {
                                *iparams->stringp++ = *ihp++;
                                iparams->stringspace--;
                        }

                        *iparams->stringp++ = 0;
                        iparams->stringspace--;

                        iparams->argc++;
                }
        }

        /* set argv[0] to point to original file name */
        suword(iparams->uap->argv, (int)iparams->uap->fname);

        return(0);
}