subr_module.c

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/*-
 * Copyright (c) 1998 Michael Smith
 * 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.
 *
 * 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/linker.h>

/*
 * Preloaded module support
 */

vm_offset_t preload_addr_relocate = 0;
caddr_t preload_metadata;

/*
 * Search for the preloaded module (name)
 */
caddr_t
preload_search_by_name(const char *name)
{
    caddr_t     curp;
    uint32_t    *hdr;
    int         next;
    
    if (preload_metadata != NULL) {
        
        curp = preload_metadata;
        for (;;) {
            hdr = (uint32_t *)curp;
            if (hdr[0] == 0 && hdr[1] == 0)
                break;

            /* Search for a MODINFO_NAME field */
            if ((hdr[0] == MODINFO_NAME) &&
                !strcmp(name, curp + sizeof(uint32_t) * 2))
                return(curp);

            /* skip to next field */
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        }
    }
    return(NULL);
}

/*
 * Search for the first preloaded module of (type)
 */
caddr_t
preload_search_by_type(const char *type)
{
    caddr_t     curp, lname;
    uint32_t    *hdr;
    int         next;

    if (preload_metadata != NULL) {

        curp = preload_metadata;
        lname = NULL;
        for (;;) {
            hdr = (uint32_t *)curp;
            if (hdr[0] == 0 && hdr[1] == 0)
                break;

            /* remember the start of each record */
            if (hdr[0] == MODINFO_NAME)
                lname = curp;

            /* Search for a MODINFO_TYPE field */
            if ((hdr[0] == MODINFO_TYPE) &&
                !strcmp(type, curp + sizeof(uint32_t) * 2))
                return(lname);

            /* skip to next field */
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        }
    }
    return(NULL);
}

/*
 * Walk through the preloaded module list
 */
caddr_t
preload_search_next_name(caddr_t base)
{
    caddr_t     curp;
    uint32_t    *hdr;
    int         next;
    
    if (preload_metadata != NULL) {
        
        /* Pick up where we left off last time */
        if (base) {
            /* skip to next field */
            curp = base;
            hdr = (uint32_t *)curp;
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        } else
            curp = preload_metadata;

        for (;;) {
            hdr = (uint32_t *)curp;
            if (hdr[0] == 0 && hdr[1] == 0)
                break;

            /* Found a new record? */
            if (hdr[0] == MODINFO_NAME)
                return curp;

            /* skip to next field */
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        }
    }
    return(NULL);
}

/*
 * Given a preloaded module handle (mod), return a pointer
 * to the data for the attribute (inf).
 */
caddr_t
preload_search_info(caddr_t mod, int inf)
{
    caddr_t     curp;
    uint32_t    *hdr;
    uint32_t    type = 0;
    int         next;

    curp = mod;
    for (;;) {
        hdr = (uint32_t *)curp;
        /* end of module data? */
        if (hdr[0] == 0 && hdr[1] == 0)
            break;
        /* 
         * We give up once we've looped back to what we were looking at 
         * first - this should normally be a MODINFO_NAME field.
         */
        if (type == 0) {
            type = hdr[0];
        } else {
            if (hdr[0] == type)
                break;
        }
        
        /* 
         * Attribute match? Return pointer to data.
         * Consumer may safely assume that size value precedes  
         * data.
         */
        if (hdr[0] == inf)
            return(curp + (sizeof(uint32_t) * 2));

        /* skip to next field */
        next = sizeof(uint32_t) * 2 + hdr[1];
        next = roundup(next, sizeof(u_long));
        curp += next;
    }
    return(NULL);
}

/*
 * Delete a preload record by name.
 */
void
preload_delete_name(const char *name)
{
    caddr_t     curp;
    uint32_t    *hdr;
    int         next;
    int         clearing;
    
    if (preload_metadata != NULL) {
        
        clearing = 0;
        curp = preload_metadata;
        for (;;) {
            hdr = (uint32_t *)curp;
            if (hdr[0] == 0 && hdr[1] == 0)
                break;

            /* Search for a MODINFO_NAME field */
            if (hdr[0] == MODINFO_NAME) {
                if (!strcmp(name, curp + sizeof(uint32_t) * 2))
                    clearing = 1;       /* got it, start clearing */
                else if (clearing)
                    clearing = 0;       /* at next one now.. better stop */
            }
            if (clearing)
                hdr[0] = MODINFO_EMPTY;

            /* skip to next field */
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        }
    }
}

void *
preload_fetch_addr(caddr_t mod)
{
        caddr_t *mdp;

        mdp = (caddr_t *)preload_search_info(mod, MODINFO_ADDR);
        if (mdp == NULL)
                return (NULL);
        return (*mdp + preload_addr_relocate);
}

size_t
preload_fetch_size(caddr_t mod)
{
        size_t *mdp;

        mdp = (size_t *)preload_search_info(mod, MODINFO_SIZE);
        if (mdp == NULL)
                return (0);
        return (*mdp);
}

/* Called from locore on i386.  Convert physical pointers to kvm. Sigh. */
void
preload_bootstrap_relocate(vm_offset_t offset)
{
    caddr_t     curp;
    uint32_t    *hdr;
    vm_offset_t *ptr;
    int         next;
    
    if (preload_metadata != NULL) {
        
        curp = preload_metadata;
        for (;;) {
            hdr = (uint32_t *)curp;
            if (hdr[0] == 0 && hdr[1] == 0)
                break;

            /* Deal with the ones that we know we have to fix */
            switch (hdr[0]) {
            case MODINFO_ADDR:
            case MODINFO_METADATA|MODINFOMD_SSYM:
            case MODINFO_METADATA|MODINFOMD_ESYM:
                ptr = (vm_offset_t *)(curp + (sizeof(uint32_t) * 2));
                *ptr += offset;
                break;
            }
            /* The rest is beyond us for now */

            /* skip to next field */
            next = sizeof(uint32_t) * 2 + hdr[1];
            next = roundup(next, sizeof(u_long));
            curp += next;
        }
    }
}