runprogram.c

/*
 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
 *      The President and Fellows of Harvard College.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY 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 UNIVERSITY 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.
 */

/*
 * Sample/test code for running a user program.  You can use this for
 * reference when implementing the execv() system call. Remember though
 * that execv() needs to do more than this function does.
 */

#include <types.h>
#include <kern/errno.h>
#include <kern/fcntl.h>
#include <lib.h>
#include <proc.h>
#include <current.h>
#include <addrspace.h>
#include <vm.h>
#include <vfs.h>
#include <syscall.h>
#include <test.h>

/*
 * Load program "progname" and start running it in usermode.
 * Does not return except on error.
 *
 * Calls vfs_open on progname and thus may destroy it.
 */
int
runprogram(char *progname)
{
        struct addrspace *as;
        struct vnode *v;
        vaddr_t entrypoint, stackptr;
        int result;

        /* Open the file. */
        result = vfs_open(progname, O_RDONLY, 0, &v);
        if (result) {
                return result;
        }

        /* We should be a new process. */
        KASSERT(curproc_getas() == NULL);

        /* Create a new address space. */
        as = as_create();
        if (as ==NULL) {
                vfs_close(v);
                return ENOMEM;
        }

        /* Switch to it and activate it. */
        curproc_setas(as);
        as_activate();

        /* Load the executable. */
        result = load_elf(v, &entrypoint);
        if (result) {
                /* p_addrspace will go away when curproc is destroyed */
                vfs_close(v);
                return result;
        }

        /* Done with the file now. */
        vfs_close(v);

        /* Define the user stack in the address space */
        result = as_define_stack(as, &stackptr);
        if (result) {
                /* p_addrspace will go away when curproc is destroyed */
                return result;
        }

        /* Warp to user mode. */
        enter_new_process(0 /*argc*/, NULL /*userspace addr of argv*/,
                          stackptr, entrypoint);
        
        /* enter_new_process does not return. */
        panic("enter_new_process returned\n");
        return EINVAL;
}