config.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

    /* This could be called from an AddModule httpd.conf command,
     * after the file has been linked and the module structure within it
     * teased out...
     */

    if (m->version != MODULE_MAGIC_NUMBER_MAJOR) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                     "%s: module \"%s\" is not compatible with this "
                     "version of Apache (found %d, need %d).",
                     ap_server_argv0, m->name, m->version,
                     MODULE_MAGIC_NUMBER_MAJOR);
        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                     "Please contact the vendor for the correct version.");
        exit(1);
    }

    if (m->next == NULL) {
        m->next = ap_top_module;
        ap_top_module = m;
    }

    if (m->module_index == -1) {
        m->module_index = total_modules++;
        dynamic_modules++;

        if (dynamic_modules > DYNAMIC_MODULE_LIMIT) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "%s: module \"%s\" could not be loaded, because"
                         " the dynamic", ap_server_argv0, m->name);
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "module limit was reached. Please increase "
                         "DYNAMIC_MODULE_LIMIT and recompile.");
            exit(1);
        }
    }

    /* Some C compilers put a complete path into __FILE__, but we want
     * only the filename (e.g. mod_includes.c). So check for path
     * components (Unix and DOS), and remove them.
     */

    if (ap_strrchr_c(m->name, '/'))
        m->name = 1 + ap_strrchr_c(m->name, '/');

    if (ap_strrchr_c(m->name, '\\'))
        m->name = 1 + ap_strrchr_c(m->name, '\\');

#ifdef _OSD_POSIX
    /* __FILE__ =
     * "*POSIX(/home/martin/apache/src/modules/standard/mod_info.c)"
     */

    /* We cannot fix the string in-place, because it's const */
    if (m->name[strlen(m->name)-1] == ')') {
        char *tmp = strdup(m->name); /* FIXME: memory leak, albeit a small one */
        tmp[strlen(tmp)-1] = '\0';
        m->name = tmp;
    }
#endif /*_OSD_POSIX*/

    /*  FIXME: is this the right place to call this?
     *  It doesn't appear to be
     */
    ap_register_hooks(m, p);
}

/*
 * remove_module undoes what add_module did. There are some caveats:
 * when the module is removed, its slot is lost so all the current
 * per-dir and per-server configurations are invalid. So we should
 * only ever call this function when you are invalidating almost
 * all our current data. I.e. when doing a restart.
 */

AP_DECLARE(void) ap_remove_module(module *m)
{
    module *modp;

    modp = ap_top_module;
    if (modp == m) {
        /* We are the top module, special case */
        ap_top_module = modp->next;
        m->next = NULL;
    }
    else {
        /* Not the top module, find use. When found modp will
         * point to the module _before_ us in the list
         */

        while (modp && modp->next != m) {
            modp = modp->next;
        }

        if (!modp) {
            /* Uh-oh, this module doesn't exist */
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
                         "Cannot remove module %s: not found in module list",
                         m->name);
            return;
        }

        /* Eliminate us from the module list */
        modp->next = modp->next->next;
    }

    m->module_index = -1; /* simulate being unloaded, should
                           * be unnecessary */
    dynamic_modules--;
    total_modules--;
}

AP_DECLARE(void) ap_add_loaded_module(module *mod, apr_pool_t *p)
{
    module **m;

    /*
     *  Add module pointer to top of chained module list
     */
    ap_add_module(mod, p);

    /*
     *  And module pointer to list of loaded modules
     *
     *  Notes: 1. ap_add_module() would already complain if no more space
     *            exists for adding a dynamically loaded module
     *         2. ap_add_module() accepts double inclusion, so we have
     *            to accept this, too.
     */
    for (m = ap_loaded_modules; *m != NULL; m++)
        ;
    *m++ = mod;
    *m = NULL;
}

AP_DECLARE(void) ap_remove_loaded_module(module *mod)
{
    module **m;
    module **m2;
    int done;

    /*
     *  Remove module pointer from chained module list
     */
    ap_remove_module(mod);

    /*
     *  Remove module pointer from list of loaded modules
     *
     *  Note: 1. We cannot determine if the module was successfully
     *           removed by ap_remove_module().
     *        2. We have not to complain explicity when the module
     *           is not found because ap_remove_module() did it
     *           for us already.
     */
    for (m = m2 = ap_loaded_modules, done = 0; *m2 != NULL; m2++) {
        if (*m2 == mod && done == 0)
            done = 1;
        else
            *m++ = *m2;
    }

    *m = NULL;
}

AP_DECLARE(void) ap_setup_prelinked_modules(process_rec *process)
{
    module **m;
    module **m2;

    apr_hook_global_pool=process->pconf;

    /*
     *  Initialise total_modules variable and module indices
     */
    total_modules = 0;
    for (m = ap_preloaded_modules; *m != NULL; m++)
        (*m)->module_index = total_modules++;

    /*
     *  Initialise list of loaded modules
     */
    ap_loaded_modules = (module **)apr_palloc(process->pool,
        sizeof(module *) * (total_modules + DYNAMIC_MODULE_LIMIT + 1));

    if (ap_loaded_modules == NULL) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                     "Ouch!  Out of memory in ap_setup_prelinked_modules()!");
    }

    for (m = ap_preloaded_modules, m2 = ap_loaded_modules; *m != NULL; )
        *m2++ = *m++;

    *m2 = NULL;

    /*
     *   Initialize chain of linked (=activate) modules
     */
    for (m = ap_prelinked_modules; *m != NULL; m++)
        ap_add_module(*m, process->pconf);

    apr_hook_sort_all();
}

AP_DECLARE(const char *) ap_find_module_name(module *m)
{
    return m->name;
}

AP_DECLARE(module *) ap_find_linked_module(const char *name)
{
    module *modp;

    for (modp = ap_top_module; modp; modp = modp->next) {
        if (strcmp(modp->name, name) == 0)
            return modp;
    }

    return NULL;
}

/* Add a named module.  Returns 1 if module found, 0 otherwise.  */
AP_DECLARE(int) ap_add_named_module(const char *name, apr_pool_t *p)
{
    module *modp;
    int i = 0;

    for (modp = ap_loaded_modules[i]; modp; modp = ap_loaded_modules[++i]) {
        if (strcmp(modp->name, name) == 0) {
            /* Only add modules that are not already enabled.  */
            if (modp->next == NULL) {
                ap_add_module(modp, p);
            }

            return 1;
        }
    }

    return 0;
}

/*****************************************************************
 *
 * Resource, access, and .htaccess config files now parsed by a common
 * command loop.
 *
 * Let's begin with the basics; parsing the line and
 * invoking the function...
 */

static const char *invoke_cmd(const command_rec *cmd, cmd_parms *parms,
                              void *mconfig, const char *args)
{
    char *w, *w2, *w3;
    const char *errmsg = NULL;

    if ((parms->override & cmd->req_override) == 0)
        return apr_pstrcat(parms->pool, cmd->name, " not allowed here", NULL);

    parms->info = cmd->cmd_data;
    parms->cmd = cmd;

    switch (cmd->args_how) {
    case RAW_ARGS:
#ifdef RESOLVE_ENV_PER_TOKEN
        args = ap_resolve_env(parms->pool,args);
#endif
        return cmd->AP_RAW_ARGS(parms, mconfig, args);

    case NO_ARGS:
        if (*args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes no arguments",
                               NULL);

        return cmd->AP_NO_ARGS(parms, mconfig);

    case TAKE1:
        w = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes one argument",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE1(parms, mconfig, w);

    case TAKE2:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *w2 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes two arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE2(parms, mconfig, w, w2);

    case TAKE12:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes 1-2 arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE2(parms, mconfig, w, *w2 ? w2 : NULL);

    case TAKE3:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);
        w3 = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *w2 == '\0' || *w3 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name, " takes three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE23:
        w = ap_getword_conf(parms->pool, &args);
        w2 = ap_getword_conf(parms->pool, &args);
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || *w2 == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes two or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE123:
        w = ap_getword_conf(parms->pool, &args);
        w2 = *args ? ap_getword_conf(parms->pool, &args) : NULL;
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes one, two or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case TAKE13:
        w = ap_getword_conf(parms->pool, &args);
        w2 = *args ? ap_getword_conf(parms->pool, &args) : NULL;
        w3 = *args ? ap_getword_conf(parms->pool, &args) : NULL;

        if (*w == '\0' || (w2 && *w2 && !w3) || *args != 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " takes one or three arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        return cmd->AP_TAKE3(parms, mconfig, w, w2, w3);

    case ITERATE:
        while (*(w = ap_getword_conf(parms->pool, &args)) != '\0') {

            errmsg = cmd->AP_TAKE1(parms, mconfig, w);

            if (errmsg && strcmp(errmsg, DECLINE_CMD) != 0)
                return errmsg;
        }

        return errmsg;

    case ITERATE2:
        w = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || *args == 0)
            return apr_pstrcat(parms->pool, cmd->name,
                               " requires at least two arguments",
                               cmd->errmsg ? ", " : NULL, cmd->errmsg, NULL);

        while (*(w2 = ap_getword_conf(parms->pool, &args)) != '\0') {

            errmsg = cmd->AP_TAKE2(parms, mconfig, w, w2);

            if (errmsg && strcmp(errmsg, DECLINE_CMD) != 0)
                return errmsg;
        }

        return errmsg;

    case FLAG:
        w = ap_getword_conf(parms->pool, &args);

        if (*w == '\0' || (strcasecmp(w, "on") && strcasecmp(w, "off")))
            return apr_pstrcat(parms->pool, cmd->name, " must be On or Off",
                               NULL);

        return cmd->AP_FLAG(parms, mconfig, strcasecmp(w, "off") != 0);

    default:
        return apr_pstrcat(parms->pool, cmd->name,
                           " is improperly configured internally (server bug)",
                           NULL);
    }
}

AP_CORE_DECLARE(const command_rec *) ap_find_command(const char *name,
                                                     const command_rec *cmds)
{
    while (cmds->name) {
        if (!strcasecmp(name, cmds->name))
            return cmds;

        ++cmds;
    }

    return NULL;
}