sect.c

一款类linux的操作系统源码

/*
 *  Roadrunner/pk
 *    Copyright (C) 1989-2001  Cornfed Systems, Inc.
 *
 *  The Roadrunner/pk operating system is free software; you can
 *  redistribute and/or modify it under the terms of the GNU General
 *  Public License, version 2, as published by the Free Software
 *  Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT 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
 *
 *  More information about the Roadrunner/pk operating system of
 *  which this file is a part is available on the World-Wide Web
 *  at: http://www.cornfed.com.
 *
 */

#include <stdio.h>
#include <string.h>
#include <sys.h>
#include <sys/load.h>
#include <sys/mem.h>

static int
find_section(sections_t s, char *section,int count)
{
    Elf32_Ehdr *ehdr = s->ehdr;
    Elf32_Shdr *shdrtab = s->shdrtab;
    char *shstrtab = s->shstrtab;
    int i,j;
    j = 0;
    for (i = 0; i < ehdr->e_shnum; i++){
 	    if (strcmp(shstrtab + shdrtab[i].sh_name, section) == 0){
 	       j++;
 	       if(j == count)return i;
	    }
	}    
    if (i == ehdr->e_shnum)
	return (-1);
}

int
init_sections(char *filebuf, sections_t s)
{
    int i, ndx;

    bzero(s, sizeof(struct sections));

    s->ehdr = (Elf32_Ehdr *) filebuf;
    s->shdrtab = (Elf32_Shdr *) (filebuf + s->ehdr->e_shoff);
    s->shstrtab = filebuf + s->shdrtab[s->ehdr->e_shstrndx].sh_offset;
#if _DEBUG
    dump_ehdr(s);
#endif

    /* Symbol table */
    ndx = find_section(s, SYMTAB,1);
    s->symtab = (Elf32_Sym *) (filebuf + s->shdrtab[ndx].sh_offset);
    s->symtabentries = s->shdrtab[ndx].sh_size / s->shdrtab[ndx].sh_entsize;

    /* String table */
    ndx = find_section(s, STRTAB,1);
    s->strtab = filebuf + s->shdrtab[ndx].sh_offset;

    /*
     * XXX Assume there is at most one occurence of each of the following
     * sections
     */
    
    s->textndx = find_section(s, TEXT,1);
    s->datandx1 = find_section(s, DATA,1);
    s->datandx2 = find_section(s, DATA,2);
    s->datandx3 = find_section(s, DATA,3);
    s->datandx4 = find_section(s, DATA,4);

    return 0;
}

int
load_sections(sections_t s, char *filebuf, char *prog)
{
    Elf32_Shdr *shdrtab = s->shdrtab;
    u_long offset;

    s->textoff = (u_long) prog;
#if _DEBUG
    kprintf("load_sections: .text   %08x", s->textoff);
#endif
    bcopy(filebuf + shdrtab[s->textndx].sh_offset,
	  (char *) s->textoff, shdrtab[s->textndx].sh_size);
    offset = s->textoff + shdrtab[s->textndx].sh_size;

    if (s->datandx1 >= 0) {
	s->dataoff1 = offset;
#if _DEBUG
	kprintf(".data   %08x", s->dataoff1);
#endif
	bcopy(filebuf + shdrtab[s->datandx1].sh_offset,
	      (char *) s->dataoff1, shdrtab[s->datandx1].sh_size);
	offset += shdrtab[s->datandx1].sh_size;
    }

    if (s->datandx2 >= 0) {
	s->dataoff1 = offset;
#if _DEBUG
	kprintf(".data   %08x", s->dataoff1);
#endif
	bcopy(filebuf + shdrtab[s->datandx2].sh_offset,
	      (char *) s->dataoff1, shdrtab[s->datandx2].sh_size);
	offset += shdrtab[s->datandx2].sh_size;
    }

    if (s->datandx3 >= 0) {
	s->dataoff1 = offset;
#if _DEBUG
	kprintf(".data   %08x", s->dataoff1);
#endif
	bcopy(filebuf + shdrtab[s->datandx3].sh_offset,
	      (char *) s->dataoff1, shdrtab[s->datandx3].sh_size);
	offset += shdrtab[s->datandx3].sh_size;
    }

#if _DEBUG
    //kprintf("\n");
#endif

    return 0;
}