/*-
 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
 * 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.
 *
 * $FreeBSD: src/sys/boot/common/module.c,v 1.25 2003/08/25 23:30:41 obrien Exp $
 */

/*
 * file/module function dispatcher, support, etc.
 */

#include <stand.h>
#include <string.h>
#include <sys/param.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/queue.h>
#ifndef EFI
#include "libi386/libi386.h"
#endif

#include "bootstrap.h"

#define MDIR_REMOVED    0x0001
#define MDIR_NOHINTS    0x0002

struct moduledir {
        char    *d_path;        /* path of modules directory */
        u_char  *d_hints;       /* content of linker.hints file */
        int     d_hintsz;       /* size of hints data */
        int     d_flags;
        STAILQ_ENTRY(moduledir) d_link;
};

static int                      file_load(char *filename, vm_offset_t dest, struct preloaded_file **result);
static int                      file_loadraw(char *type, char *name);
static int                      file_load_dependencies(struct preloaded_file *base_mod);
static char *                   file_search(const char *name, char **extlist);
static struct kernel_module *   file_findmodule(struct preloaded_file *fp, char *modname, struct mod_depend *verinfo);
static int                      file_havepath(const char *name);
static char                     *mod_searchmodule(char *name, struct mod_depend *verinfo);
static void                     file_insert_tail(struct preloaded_file *mp);
static struct file_metadata*    metadata_next(struct file_metadata *base_mp, int type);
static void                     moduledir_readhints(struct moduledir *mdp);
static void                     moduledir_rebuild(void);

/* load address should be tweaked by first module loaded (kernel) */
static vm_offset_t      loadaddr = 0;

static const char       *default_searchpath = "modules;KERNEL";
static const char       *local_module_path = "../modules.local";

static STAILQ_HEAD(, moduledir) moduledir_list = STAILQ_HEAD_INITIALIZER(moduledir_list);

struct preloaded_file *preloaded_files = NULL;

static char *kld_ext_list[] = {
    ".ko",
    "",
    NULL
};

/*
 * load an object, either a disk file or code module.
 *
 * To load a file, the syntax is:
 *
 * load -t <type> <path>
 *
 * code modules are loaded as:
 *
 * load <path> <options>
 */
COMMAND_SET(load, "load", "load a kernel or module", command_load);

static int
command_load(int argc, char *argv[])
{
    char        *typestr;
    int         dofile, dokld, ch, error;

    dokld = dofile = 0;
    optind = 1;
    optreset = 1;
    typestr = NULL;
    if (argc == 1) {
        command_errmsg = "no filename specified";
        return(CMD_ERROR);
    }
    while ((ch = getopt(argc, argv, "kt:")) != -1) {
        switch(ch) {
        case 'k':
            dokld = 1;
            break;
        case 't':
            typestr = optarg;
            dofile = 1;
            break;
        case '?':
        default:
            /* getopt has already reported an error */
            return(CMD_OK);
        }
    }
    argv += (optind - 1);
    argc -= (optind - 1);

    /*
     * Request to load a raw file?
     */
    if (dofile) {
        if ((argc != 2) || (typestr == NULL) || (*typestr == 0)) {
            command_errmsg = "invalid load type";
            return(CMD_ERROR);
        }
        return(file_loadraw(typestr, argv[1]));
    }
    /*
     * Do we have explicit KLD load ?
     */
    if (dokld || file_havepath(argv[1])) {
        error = mod_loadkld(argv[1], argc - 2, argv + 2);
        if (error == EEXIST) {
            snprintf(command_errbuf, sizeof(command_errbuf),
                "warning: KLD '%s' already loaded", argv[1]);
        }
        return (error == 0 ? CMD_OK : CMD_ERROR);
    }
    /*
     * Looks like a request for a module.
     */
    error = mod_load(argv[1], NULL, argc - 2, argv + 2);
    if (error == EEXIST) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "warning: module '%s' already loaded", argv[1]);
    }
    return (error == 0 ? CMD_OK : CMD_ERROR);
}

COMMAND_SET(unload, "unload", "unload all modules", command_unload);

static int
command_unload(int argc, char *argv[])
{
    struct preloaded_file       *fp;

    while (preloaded_files != NULL) {
        fp = preloaded_files;
        preloaded_files = preloaded_files->f_next;
        file_discard(fp);
    }
    loadaddr = 0;
    unsetenv("kernelname");
    return(CMD_OK);
}

COMMAND_SET(crc, "crc", "calculate crc for file", command_crc);

uint32_t iscsi_crc32(const void *buf, size_t size);
uint32_t iscsi_crc32_ext(const void *buf, size_t size, uint32_t ocrc);

static int
command_crc(int argc, char *argv[])
{
    char        *name;
    char        *cp;
    int         i;
    int         fd, got, tot;
    int         error;
    uint32_t    crc;
    char        *buf;

    if (argc == 1) {
        command_errmsg = "no filename specified";
        return(CMD_ERROR);
    }
    buf = malloc(8192);

    error = 0;
    printf("size\tcrc\t name\n");
    for (i = 1; i < argc; ++i) {
        /* locate the file on the load path */
        cp = file_search(argv[i], NULL);
        if (cp == NULL) {
            snprintf(command_errbuf, sizeof(command_errbuf),
                "can't find '%s'", argv[i]);
            error = CMD_ERROR;
            break;
        }
        name = cp;

        if ((fd = rel_open(name, NULL, O_RDONLY)) < 0) {
            snprintf(command_errbuf, sizeof(command_errbuf),
                "can't open '%s': %s", name, strerror(errno));
            free(name);
            error = CMD_ERROR;
            break;
        }
        tot = 0;
        crc = 0;
        for (;;) {
            got = read(fd, buf, 8192);
            if (got == 0)
                break;
            if (got < 0) {
                printf("error reading '%s': %s\n",
                    name, strerror(errno));
                break;
            }
            if (crc == 0)
                crc = iscsi_crc32(buf, got);
            else
                crc = iscsi_crc32_ext(buf, got, crc);
            tot += got;
        }
        printf("%7d %08x %s\n", tot, crc, name);
        free(name);
        close(fd);
    }
    free (buf);
    if (error == 0)
        error = CMD_OK;
    return error;
}

COMMAND_SET(lsmod, "lsmod", "list loaded modules", command_lsmod);

static int
command_lsmod(int argc, char *argv[])
{
    struct preloaded_file       *fp;
    struct kernel_module        *mp;
    struct file_metadata        *md;
    char                        lbuf[80];
    int                         ch, verbose;

    verbose = 0;
    optind = 1;
    optreset = 1;
    while ((ch = getopt(argc, argv, "v")) != -1) {
        switch(ch) {
        case 'v':
            verbose = 1;
            break;
        case '?':
        default:
            /* getopt has already reported an error */
            return(CMD_OK);
        }
    }

    pager_open();
    for (fp = preloaded_files; fp; fp = fp->f_next) {
        sprintf(lbuf, " %p: %s (%s, 0x%lx)\n",
                (void *) fp->f_addr, fp->f_name, fp->f_type, (long) fp->f_size);
        pager_output(lbuf);
        if (fp->f_args != NULL) {
            pager_output("    args: ");
            pager_output(fp->f_args);
            pager_output("\n");
        }
        if (fp->f_modules) {
            pager_output("  modules: ");
            for (mp = fp->f_modules; mp; mp = mp->m_next) {
                sprintf(lbuf, "%s.%d ", mp->m_name, mp->m_version);
                pager_output(lbuf);
            }
            pager_output("\n");
        }
        if (verbose) {
            /* XXX could add some formatting smarts here to display some better */
            for (md = fp->f_metadata; md != NULL; md = md->md_next) {
                sprintf(lbuf, "      0x%04x, 0x%lx\n", md->md_type, (long) md->md_size);
                pager_output(lbuf);
            }
        }
    }
    pager_close();
    return(CMD_OK);
}

/*
 * File level interface, functions file_*
 */
static int
file_load(char *filename, vm_offset_t dest, struct preloaded_file **result)
{
    struct preloaded_file *fp;
    int error;
    int i;

    error = EFTYPE;
    for (i = 0, fp = NULL; file_formats[i] && fp == NULL; i++) {
        error = (file_formats[i]->l_load)(filename, dest, &fp);
        if (error == 0) {
            fp->f_loader = i;           /* remember the loader */
            *result = fp;
            break;
        }
        if (error == EFTYPE)
            continue;           /* Unknown to this handler? */
        if (error) {
            snprintf(command_errbuf, sizeof(command_errbuf),
                "can't load file '%s': %s", filename, strerror(error));
            break;
        }
    }
    return (error);
}

static int
file_load_dependencies(struct preloaded_file *base_file)
{
    struct file_metadata *md;
    struct preloaded_file *fp;
    struct mod_depend *verinfo;
    struct kernel_module *mp;
    char *dmodname;
    int error;

    md = file_findmetadata(base_file, MODINFOMD_DEPLIST);
    if (md == NULL)
        return (0);

    error = 0;
    do {
        verinfo = (struct mod_depend*)md->md_data;
        dmodname = (char *)(verinfo + 1);
        if (file_findmodule(NULL, dmodname, verinfo) == NULL) {
            printf("loading required module '%s'\n", dmodname);
            error = mod_load(dmodname, verinfo, 0, NULL);
            if (error)
                break;
            /*
             * If module loaded via kld name which isn't listed
             * in the linker.hints file, we should check if it have
             * required version.
             */
            mp = file_findmodule(NULL, dmodname, verinfo);
            if (mp == NULL) {
                snprintf(command_errbuf, sizeof(command_errbuf),
                    "module '%s' exists but with wrong version", dmodname);
                error = ENOENT;
                break;
            }
        }
        md = metadata_next(md, MODINFOMD_DEPLIST);
    } while (md);
    if (!error)
        return (0);

    /* Load failed; discard everything */
    while (base_file != NULL) {
        fp = base_file;
        base_file = base_file->f_next;
        file_discard(fp);
    }
    return (error);
}

/*
 * We've been asked to load (name) as (type), so just suck it in,
 * no arguments or anything.
 */
static int
file_loadraw(char *type, char *name)
{
    struct preloaded_file       *fp;
    char                        *cp;
    int                         fd, got;
    vm_offset_t                 laddr;

    /* We can't load first */
    if (file_findfile(NULL, NULL) == NULL) {
        command_errmsg = "can't load file before kernel";
        return(CMD_ERROR);
    }

    /* locate the file on the load path */
    cp = file_search(name, NULL);
    if (cp == NULL) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "can't find '%s'", name);
        return(CMD_ERROR);
    }
    name = cp;

    if ((fd = rel_open(name, NULL, O_RDONLY)) < 0) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "can't open '%s': %s", name, strerror(errno));
        free(name);
        return(CMD_ERROR);
    }

    laddr = loadaddr;
    for (;;) {
        /* read in 4k chunks; size is not really important */
#ifndef EFI
        if (laddr + 4096 > heapbase) {
            snprintf(command_errbuf, sizeof(command_errbuf),
                "error reading '%s': out of load memory", name);
            free(name);
            close(fd);
            return(CMD_ERROR);
        }
#endif
        got = archsw.arch_readin(fd, laddr, 4096);
        if (got == 0)                           /* end of file */
            break;
        if (got < 0) {                          /* error */
            snprintf(command_errbuf, sizeof(command_errbuf),
                "error reading '%s': %s", name, strerror(errno));
            free(name);
            close(fd);
            return(CMD_ERROR);
        }
        laddr += got;
    }

    /* Looks OK so far; create & populate control structure */
    fp = file_alloc();
    fp->f_name = rel_rootpath(name);
    fp->f_type = strdup(type);
    fp->f_args = NULL;
    fp->f_metadata = NULL;
    fp->f_loader = -1;
    fp->f_addr = loadaddr;
    fp->f_size = laddr - loadaddr;

    /* recognise space consumption */
    loadaddr = laddr;

    /* Add to the list of loaded files */
    file_insert_tail(fp);
    close(fd);
    return(CMD_OK);
}

/*
 * Load the module (name), pass it (argc),(argv), add container file
 * to the list of loaded files.
 * If module is already loaded just assign new argc/argv.
 */
int
mod_load(char *modname, struct mod_depend *verinfo, int argc, char *argv[])
{
    struct kernel_module        *mp;
    int                         err;
    char                        *filename;

    if (file_havepath(modname)) {
        printf("Warning: mod_load() called instead of mod_loadkld() for module '%s'\n", modname);
        return (mod_loadkld(modname, argc, argv));
    }
    /* see if module is already loaded */
    mp = file_findmodule(NULL, modname, verinfo);
    if (mp) {
#ifdef moduleargs
        if (mp->m_args)
            free(mp->m_args);
        mp->m_args = unargv(argc, argv);
#endif
        snprintf(command_errbuf, sizeof(command_errbuf),
            "warning: module '%s' already loaded", mp->m_name);
        return (0);
    }
    /* locate file with the module on the search path */
    filename = mod_searchmodule(modname, verinfo);
    if (filename == NULL) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "can't find '%s'", modname);
        return (ENOENT);
    }
    err = mod_loadkld(filename, argc, argv);
    return (err);
}

/*
 * Load specified KLD. If path is omitted, then try to locate it via
 * search path.
 */
int
mod_loadkld(const char *kldname, int argc, char *argv[])
{
    struct preloaded_file       *fp, *last_file;
    int                         err;
    char                        *filename;

    /*
     * Get fully qualified KLD name
     */
    filename = file_search(kldname, kld_ext_list);
    if (filename == NULL) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "can't find '%s'", kldname);
        return (ENOENT);
    }
    /*
     * Check if KLD already loaded
     */
    fp = file_findfile(filename, NULL);
    if (fp) {
        snprintf(command_errbuf, sizeof(command_errbuf),
            "warning: KLD '%s' already loaded", filename);
        free(filename);
        return (0);
    }
    for (last_file = preloaded_files;
         last_file != NULL && last_file->f_next != NULL;
         last_file = last_file->f_next)
        ;

    do {
        err = file_load(filename, loadaddr, &fp);
        if (err)
            break;
        fp->f_args = unargv(argc, argv);
        loadaddr = fp->f_addr + fp->f_size;
        file_insert_tail(fp);           /* Add to the list of loaded files */
        if (file_load_dependencies(fp) != 0) {
            err = ENOENT;
            last_file->f_next = NULL;
            loadaddr = last_file->f_addr + last_file->f_size;
            fp = NULL;
            break;
        }
    } while(0);
    if (err == EFTYPE)
        snprintf(command_errbuf, sizeof(command_errbuf),
            "don't know how to load module '%s'", filename);
    if (err && fp)
        file_discard(fp);
    free(filename);
    return (err);
}

/*
 * Find a file matching (name) and (type).
 * NULL may be passed as a wildcard to either.
 */
struct preloaded_file *
file_findfile(char *name, char *type)
{
    struct preloaded_file *fp;
    char *rootpath;

    rootpath = NULL;
    if (name != NULL)
        rootpath = rel_rootpath(name);

    for (fp = preloaded_files; fp != NULL; fp = fp->f_next) {
        if (((rootpath == NULL) || !strcmp(rootpath, fp->f_name)) &&
            ((type == NULL) || !strcmp(type, fp->f_type)))
            break;
    }

    if (rootpath != NULL)
        free(rootpath);
    return (fp);
}

/*
 * Find a module matching (name) inside of given file.
 * NULL may be passed as a wildcard.
 */
static struct kernel_module *
file_findmodule(struct preloaded_file *fp, char *modname,
        struct mod_depend *verinfo)
{
    struct kernel_module *mp, *best;
    int bestver, mver;

    if (fp == NULL) {
        for (fp = preloaded_files; fp; fp = fp->f_next) {
            mp = file_findmodule(fp, modname, verinfo);
            if (mp)
                return (mp);
        }
        return (NULL);
    }

    best = NULL;
    bestver = 0;
    for (mp = fp->f_modules; mp; mp = mp->m_next) {
        if (strcmp(modname, mp->m_name) == 0) {
            if (verinfo == NULL)
                return (mp);
            mver = mp->m_version;
            if (mver == verinfo->md_ver_preferred)
                return (mp);
            if (mver >= verinfo->md_ver_minimum &&
                mver <= verinfo->md_ver_maximum &&
                mver > bestver) {
                best = mp;
                bestver = mver;
            }
        }
    }
    return (best);
}
/*
 * Make a copy of (size) bytes of data from (p), and associate them as
 * metadata of (type) to the module (mp).
 */
void
file_addmetadata(struct preloaded_file *fp, int type, size_t size, void *p)
{
    struct file_metadata        *md;

    md = malloc(sizeof(struct file_metadata) - sizeof(md->md_data) + size);
    md->md_size = size;
    md->md_type = type;
    bcopy(p, md->md_data, size);
    md->md_next = fp->f_metadata;
    fp->f_metadata = md;
}

/*
 * Find a metadata object of (type) associated with the file (fp)
 */
struct file_metadata *
file_findmetadata(struct preloaded_file *fp, int type)
{
    struct file_metadata *md;

    for (md = fp->f_metadata; md != NULL; md = md->md_next)
        if (md->md_type == type)
            break;
    return(md);
}

static struct file_metadata *
metadata_next(struct file_metadata *md, int type)
{
    if (md == NULL)
        return (NULL);
    while((md = md->md_next) != NULL)
        if (md->md_type == type)
            break;
    return (md);
}

static char *emptyextlist[] = { "", NULL };

/*
 * Check if the given file is in place and return full path to it.
 */
static char *
file_lookup(const char *path, const char *name, int namelen, char **extlist)
{
    struct stat st;
    char        *result, *cp, **cpp;
    size_t      pathlen, extlen;

    pathlen = strlen(path);
    extlen = 0;
    if (extlist == NULL)
        extlist = emptyextlist;
    for (cpp = extlist; *cpp; cpp++)
        extlen = MAX(extlen, strlen(*cpp));
    result = malloc(pathlen + namelen + extlen + 2 + 7 + 1);
    if (result == NULL)
        return (NULL);
    bcopy(path, result, pathlen);
    if (pathlen > 0 && result[pathlen - 1] != '/')
        result[pathlen++] = '/';
    cp = result + pathlen;
    bcopy(name, cp, namelen);
    cp += namelen;
    for (cpp = extlist; *cpp; cpp++) {
        strcpy(cp, *cpp);
        if (rel_stat(result, &st) == 0) {
            if (S_ISREG(st.st_mode)) {
                return result;
            } else if (S_ISDIR(st.st_mode)) {
                strcat(result, "/kernel");
                if (rel_stat(result, &st) == 0 && S_ISREG(st.st_mode)) {
                    return result;
                }
            }
        }
    }
    free(result);
    return NULL;
}

/*
 * Check if file name have any qualifiers
 */
static int
file_havepath(const char *name)
{
    const char          *cp;

    archsw.arch_getdev(NULL, name, &cp);
    return (cp != name || strchr(name, '/') != NULL);
}

/*
 * Attempt to find the file (name) on the module searchpath.
 * If (name) is qualified in any way, we simply check it and
 * return it or NULL.  If it is not qualified, then we attempt
 * to construct a path using entries in the environment variable
 * module_path.
 *
 * The path we return a pointer to need never be freed, as we manage
 * it internally.
 */
static char *
file_search(const char *name, char **extlist)
{
    struct moduledir    *mdp;
    struct stat         sb;
    char                *result;
    int                 namelen;

    /* Don't look for nothing */
    if (name == NULL || *name == 0)
        return(NULL);

    /*
     * Qualified name.  If it is a directory tag on
     * a "/kernel" to it.
     */
    if (file_havepath(name)) {
        /* Qualified, so just see if it exists */
        if (rel_stat(name, &sb) == 0) {
            if (S_ISDIR(sb.st_mode)) {
                result = malloc(strlen(name) + 7 + 1);
                sprintf(result, "%s/kernel", name);
                return(result);
            } else {
                return(strdup(name));
            }
        }
        return(NULL);
    }

    moduledir_rebuild();
    result = NULL;
    namelen = strlen(name);
    STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
        result = file_lookup(mdp->d_path, name, namelen, extlist);
        if (result)
            break;
    }
    return(result);
}

#define INT_ALIGN(base, ptr) \
        ptr = (base) + roundup2((ptr) - (base), sizeof(int))

static char *
mod_search_hints(struct moduledir *mdp, const char *modname,
        struct mod_depend *verinfo)
{
    u_char      *cp, *recptr, *bufend, *best;
    char        *result;
    int         *intp, bestver, blen, clen, found, ival, modnamelen, reclen;

    moduledir_readhints(mdp);
    modnamelen = strlen(modname);
    found = 0;
    result = NULL;
    bestver = 0;
    if (mdp->d_hints == NULL)
        goto bad;
    recptr = mdp->d_hints;
    bufend = recptr + mdp->d_hintsz;
    clen = blen = 0;
    best = cp = NULL;
    while (recptr < bufend && !found) {
        intp = (int*)recptr;
        reclen = *intp++;
        ival = *intp++;
        cp = (char*)intp;
        switch (ival) {
        case MDT_VERSION:
            clen = *cp++;
            if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
                break;
            cp += clen;
            INT_ALIGN(mdp->d_hints, cp);
            ival = *(int*)cp;
            cp += sizeof(int);
            clen = *cp++;
            if (verinfo == NULL || ival == verinfo->md_ver_preferred) {
                found = 1;
                break;
            }
            if (ival >= verinfo->md_ver_minimum &&
                ival <= verinfo->md_ver_maximum &&
                ival > bestver)
            {
                bestver = ival;
                best = cp;
                blen = clen;
            }
            break;
        default:
            break;
        }
        recptr += reclen + sizeof(int);
    }
    /*
     * Finally check if KLD is in the place
     */
    if (found)
        result = file_lookup(mdp->d_path, cp, clen, NULL);
    else if (best)
        result = file_lookup(mdp->d_path, best, blen, NULL);
bad:
    /*
     * If nothing found or hints is absent - fallback to the old way
     * by using "kldname[.ko]" as module name.
     */
    if (!found && !bestver && result == NULL)
        result = file_lookup(mdp->d_path, modname, modnamelen, kld_ext_list);
    return result;
}

/*
 * Attempt to locate the file containing the module (name)
 */
static char *
mod_searchmodule(char *name, struct mod_depend *verinfo)
{
    struct      moduledir *mdp;
    char        *result;

    moduledir_rebuild();
    /*
     * Now we ready to lookup module in the given directories
     */
    result = NULL;
    STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
        result = mod_search_hints(mdp, name, verinfo);
        if (result)
            break;
    }

    return(result);
}

int
file_addmodule(struct preloaded_file *fp, char *modname, int version,
        struct kernel_module **newmp)
{
    struct kernel_module *mp;
    struct mod_depend mdepend;

    bzero(&mdepend, sizeof(mdepend));
    mdepend.md_ver_preferred = version;
    mp = file_findmodule(fp, modname, &mdepend);
    if (mp)
        return (EEXIST);
    mp = malloc(sizeof(struct kernel_module));
    if (mp == NULL)
        return (ENOMEM);
    bzero(mp, sizeof(struct kernel_module));
    mp->m_name = strdup(modname);
    mp->m_version = version;
    mp->m_fp = fp;
    mp->m_next = fp->f_modules;
    fp->f_modules = mp;
    if (newmp)
        *newmp = mp;
    return (0);
}

/*
 * Throw a file away
 */
void
file_discard(struct preloaded_file *fp)
{
    struct file_metadata        *md, *md1;
    struct kernel_module        *mp, *mp1;

    if (fp == NULL)
        return;

    md = fp->f_metadata;
    while (md) {
        md1 = md;
        md = md->md_next;
        free(md1);
    }

    mp = fp->f_modules;
    while (mp) {
        if (mp->m_name)
            free(mp->m_name);
#ifdef moduleargs
        if (mp->m_args)
            free(mp->m_args);
#endif
        mp1 = mp;
        mp = mp->m_next;
        free(mp1);
    }

    if (fp->f_name != NULL)
        free(fp->f_name);
    if (fp->f_type != NULL)
        free(fp->f_type);
    if (fp->f_args != NULL)
        free(fp->f_args);
    free(fp);
}

/*
 * Allocate a new file; must be used instead of malloc()
 * to ensure safe initialisation.
 */
struct preloaded_file *
file_alloc(void)
{
    struct preloaded_file       *fp;

    if ((fp = malloc(sizeof(struct preloaded_file))) != NULL) {
        bzero(fp, sizeof(struct preloaded_file));
    }
    return (fp);
}

/*
 * Add a module to the chain
 */
static void
file_insert_tail(struct preloaded_file *fp)
{
    struct preloaded_file       *cm;

    /* Append to list of loaded file */
    fp->f_next = NULL;
    if (preloaded_files == NULL) {
        preloaded_files = fp;
    } else {
        for (cm = preloaded_files; cm->f_next != NULL; cm = cm->f_next)
            ;
        cm->f_next = fp;
    }
}

static char *
moduledir_fullpath(struct moduledir *mdp, const char *fname)
{
    char *cp;

    cp = malloc(strlen(mdp->d_path) + strlen(fname) + 2);
    if (cp == NULL)
        return NULL;
    strcpy(cp, mdp->d_path);
    strcat(cp, "/");
    strcat(cp, fname);
    return (cp);
}

/*
 * Read linker.hints file into memory performing some sanity checks.
 */
static void
moduledir_readhints(struct moduledir *mdp)
{
    struct stat st;
    char        *path;
    int         fd, size, version;

    if (mdp->d_hints != NULL || (mdp->d_flags & MDIR_NOHINTS))
        return;
    path = moduledir_fullpath(mdp, "linker.hints");
    if (rel_stat(path, &st) != 0 ||
        st.st_size < (ssize_t)(sizeof(version) + sizeof(int)) ||
        st.st_size > 100 * 1024 || (fd = rel_open(path, NULL, O_RDONLY)) < 0) {
        free(path);
        mdp->d_flags |= MDIR_NOHINTS;
        return;
    }
    free(path);
    size = read(fd, &version, sizeof(version));
    if (size != sizeof(version) || version != LINKER_HINTS_VERSION)
        goto bad;
    size = st.st_size - size;
    mdp->d_hints = malloc(size);
    if (mdp->d_hints == NULL)
        goto bad;
    if (read(fd, mdp->d_hints, size) != size)
        goto bad;
    mdp->d_hintsz = size;
    close(fd);
    return;

bad:
    close(fd);
    if (mdp->d_hints) {
        free(mdp->d_hints);
        mdp->d_hints = NULL;
    }
    mdp->d_flags |= MDIR_NOHINTS;
}

/*
 * Extract directories from the ';' separated list, remove duplicates.
 */
static void
moduledir_rebuild(void)
{
    struct      moduledir *mdp, *mtmp;
    const char  *path, *cp, *ep, *modlocal;
    size_t      cplen;

    path = getenv("module_path");
    if (path == NULL)
        path = default_searchpath;
    /*
     * Rebuild list of module directories if it changed
     */
    STAILQ_FOREACH(mdp, &moduledir_list, d_link)
        mdp->d_flags |= MDIR_REMOVED;

    for (ep = path; *ep != 0;  ep++) {
        cp = ep;
        for (; *ep != 0 && *ep != ';'; ep++)
            ;
        /*
         * Ignore trailing slashes
         */
        for (cplen = ep - cp; cplen > 1 && cp[cplen - 1] == '/'; cplen--)
            ;
        STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
            if (strlen(mdp->d_path) != cplen || bcmp(cp, mdp->d_path, cplen) != 0)
                continue;
            mdp->d_flags &= ~MDIR_REMOVED;
            break;
        }
        if (mdp == NULL) {
            mdp = malloc(sizeof(*mdp) + cplen + 1);
            if (mdp == NULL)
                return;
            mdp->d_path = (char*)(mdp + 1);
            bcopy(cp, mdp->d_path, cplen);
            mdp->d_path[cplen] = 0;
            mdp->d_hints = NULL;
            mdp->d_flags = 0;
            STAILQ_INSERT_TAIL(&moduledir_list, mdp, d_link);
        }
        if (*ep == 0)
            break;
    }
    /*
     * Include modules.local if requested
     */
    modlocal = getenv("local_modules");
    if (modlocal != NULL && strcmp(modlocal, "YES") == 0) {
        cp = local_module_path;
        cplen = strlen(local_module_path);
        STAILQ_FOREACH(mdp, &moduledir_list, d_link) {
            if (strlen(mdp->d_path) != cplen || bcmp(cp, mdp->d_path, cplen) != 0)
                continue;
            mdp->d_flags &= ~MDIR_REMOVED;
            break;
        }
        if (mdp == NULL) {
            mdp = malloc(sizeof(*mdp) + cplen + 1);
            if (mdp == NULL)
                return;
            mdp->d_path = (char*)(mdp + 1);
            bcopy(local_module_path, mdp->d_path, cplen);
            mdp->d_path[cplen] = 0;
            mdp->d_hints = NULL;
            mdp->d_flags = 0;
            STAILQ_INSERT_TAIL(&moduledir_list, mdp, d_link);
        }
    }
    /*
     * Delete unused directories if any
     */
    mdp = STAILQ_FIRST(&moduledir_list);
    while (mdp) {
        if ((mdp->d_flags & MDIR_REMOVED) == 0) {
            mdp = STAILQ_NEXT(mdp, d_link);
        } else {
            if (mdp->d_hints)
                free(mdp->d_hints);
            mtmp = mdp;
            mdp = STAILQ_NEXT(mdp, d_link);
            STAILQ_REMOVE(&moduledir_list, mtmp, moduledir, d_link);
            free(mtmp);
        }
    }
}