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。

AP_CORE_DECLARE(const command_rec *) ap_find_command_in_modules(
                                          const char *cmd_name, module **mod)
{
    const command_rec *cmdp;
    module *modp;

    for (modp = *mod; modp; modp = modp->next) {
        if (modp->cmds && (cmdp = ap_find_command(cmd_name, modp->cmds))) {
            *mod = modp;
            return cmdp;
        }
    }

    return NULL;
}

AP_CORE_DECLARE(void *) ap_set_config_vectors(server_rec *server,
                                              ap_conf_vector_t *section_vector,
                                              const char *section,
                                              module *mod, apr_pool_t *pconf)
{
    void *section_config = ap_get_module_config(section_vector, mod);
    void *server_config = ap_get_module_config(server->module_config, mod);

    if (!section_config && mod->create_dir_config) {
        /* ### need to fix the create_dir_config functions' prototype... */
        section_config = (*mod->create_dir_config)(pconf, (char *)section);
        ap_set_module_config(section_vector, mod, section_config);
    }

    if (!server_config && mod->create_server_config) {
        server_config = (*mod->create_server_config)(pconf, server);
        ap_set_module_config(server->module_config, mod, server_config);
    }

    return section_config;
}

static const char *execute_now(char *cmd_line, const char *args,
                               cmd_parms *parms,
                               apr_pool_t *p, apr_pool_t *ptemp,
                               ap_directive_t **sub_tree,
                               ap_directive_t *parent);

static const char *ap_build_config_sub(apr_pool_t *p, apr_pool_t *temp_pool,
                                       const char *l, cmd_parms *parms,
                                       ap_directive_t **current,
                                       ap_directive_t **curr_parent,
                                       ap_directive_t **conftree)
{
    const char *retval = NULL;
    const char *args;
    char *cmd_name;
    ap_directive_t *newdir;
    module *mod = ap_top_module;
    const command_rec *cmd;

    if (*l == '#' || *l == '\0')
        return NULL;

#if RESOLVE_ENV_PER_TOKEN
    args = l;
#else
    args = ap_resolve_env(temp_pool, l);
#endif

    cmd_name = ap_getword_conf(p, &args);
    if (*cmd_name == '\0') {
        /* Note: this branch should not occur. An empty line should have
         * triggered the exit further above.
         */
        return NULL;
    }

    if (cmd_name[1] != '/') {
        char *lastc = cmd_name + strlen(cmd_name) - 1;
        if (*lastc == '>') {
            *lastc = '\0' ;
        }
        if (cmd_name[0] == '<' && *args == '\0') {
            args = ">";
        }
    }

    newdir = apr_pcalloc(p, sizeof(ap_directive_t));
    newdir->filename = parms->config_file->name;
    newdir->line_num = parms->config_file->line_number;
    newdir->directive = cmd_name;
    newdir->args = apr_pstrdup(p, args);

    if ((cmd = ap_find_command_in_modules(cmd_name, &mod)) != NULL) {
        if (cmd->req_override & EXEC_ON_READ) {
            ap_directive_t *sub_tree = NULL;

            parms->err_directive = newdir;
            retval = execute_now(cmd_name, args, parms, p, temp_pool,
                                 &sub_tree, *curr_parent);
            if (*current) {
                (*current)->next = sub_tree;
            }
            else {
                *current = sub_tree;
                if (*curr_parent) {
                    (*curr_parent)->first_child = (*current);
                }
                if (*current) {
                    (*current)->parent = (*curr_parent);
                }
            }
            if (*current) {
                if (!*conftree) {
                    /* Before walking *current to the end of the list,
                     * set the head to *current.
                     */
                    *conftree = *current;
                }
                while ((*current)->next != NULL) {
                    (*current) = (*current)->next;
                    (*current)->parent = (*curr_parent);
                }
            }
            return retval;
        }
    }

    if (cmd_name[0] == '<') {
        if (cmd_name[1] != '/') {
            (*current) = ap_add_node(curr_parent, *current, newdir, 1);
        }
        else if (*curr_parent == NULL) {
            parms->err_directive = newdir;
            return apr_pstrcat(p, cmd_name,
                               " without matching <", cmd_name + 2,
                               " section", NULL);
        }
        else {
            char *bracket = cmd_name + strlen(cmd_name) - 1;

            if (*bracket != '>') {
                parms->err_directive = newdir;
                return apr_pstrcat(p, cmd_name,
                                   "> directive missing closing '>'", NULL);
            }

            *bracket = '\0';

            if (strcasecmp(cmd_name + 2,
                           (*curr_parent)->directive + 1) != 0) {
                parms->err_directive = newdir;
                return apr_pstrcat(p, "Expected </",
                                   (*curr_parent)->directive + 1, "> but saw ",
                                   cmd_name, ">", NULL);
            }

            *bracket = '>';

            /* done with this section; move up a level */
            *current = *curr_parent;
            *curr_parent = (*current)->parent;
        }
    }
    else {
        *current = ap_add_node(curr_parent, *current, newdir, 0);
    }

    return retval;
}

AP_DECLARE(const char *) ap_build_cont_config(apr_pool_t *p,
                                              apr_pool_t *temp_pool,
                                              cmd_parms *parms,
                                              ap_directive_t **current,
                                              ap_directive_t **curr_parent,
                                              char *orig_directive)
{
    char *l;
    char *bracket;
    const char *retval;
    ap_directive_t *sub_tree = NULL;

    /* Since this function can be called recursively, allocate
     * the temporary 8k string buffer from the temp_pool rather 
     * than the stack to avoid over-running a fixed length stack.
     */
    l = apr_palloc(temp_pool, MAX_STRING_LEN);

    bracket = apr_pstrcat(p, orig_directive + 1, ">", NULL);
    while (!(ap_cfg_getline(l, MAX_STRING_LEN, parms->config_file))) {
        if (!memcmp(l, "</", 2)
            && (strcasecmp(l + 2, bracket) == 0)
            && (*curr_parent == NULL)) {
            break;
        }
        retval = ap_build_config_sub(p, temp_pool, l, parms, current,
                                     curr_parent, &sub_tree);
        if (retval != NULL)
            return retval;

        if (sub_tree == NULL && curr_parent != NULL) {
            sub_tree = *curr_parent;
        }

        if (sub_tree == NULL && current != NULL) {
            sub_tree = *current;
        }
    }

    *current = sub_tree;
    return NULL;
}

static const char *ap_walk_config_sub(const ap_directive_t *current,
                                      cmd_parms *parms,
                                      ap_conf_vector_t *section_vector)
{
    module *mod = ap_top_module;

    while (1) {
        const command_rec *cmd;

        if (!(cmd = ap_find_command_in_modules(current->directive, &mod))) {
            parms->err_directive = current;
            return apr_pstrcat(parms->pool, "Invalid command '",
                               current->directive,
                               "', perhaps mis-spelled or defined by a module "
                               "not included in the server configuration",
                               NULL);
        }
        else {
            void *dir_config = ap_set_config_vectors(parms->server,
                                                     section_vector,
                                                     parms->path,
                                                     mod,
                                                     parms->pool);
            const char *retval;

            /* Once was enough? */
            if (cmd->req_override & EXEC_ON_READ) {
                return NULL;
            }

            retval = invoke_cmd(cmd, parms, dir_config, current->args);
            if (retval == NULL) {
                return NULL;
            }

            if (strcmp(retval, DECLINE_CMD) != 0) {
                /* If the directive in error has already been set, don't
                 * replace it.  Otherwise, an error inside a container 
                 * will be reported as occuring on the first line of the
                 * container.
                 */
                if (!parms->err_directive) {
                    parms->err_directive = current;
                }

                return retval;
            }

            mod = mod->next; /* Next time around, skip this one */
        }
    }
    /* NOTREACHED */
}

AP_DECLARE(const char *) ap_walk_config(ap_directive_t *current,
                                        cmd_parms *parms,
                                        ap_conf_vector_t *section_vector)
{
    ap_conf_vector_t *oldconfig = parms->context;

    parms->context = section_vector;

    /* scan through all directives, executing each one */
    for (; current != NULL; current = current->next) {
        const char *errmsg;

        parms->directive = current;

        /* actually parse the command and execute the correct function */
        errmsg = ap_walk_config_sub(current, parms, section_vector);
        if (errmsg != NULL) {
            /* restore the context (just in case) */
            parms->context = oldconfig;
            return errmsg;
        }
    }

    parms->context = oldconfig;
    return NULL;
}

AP_DECLARE(const char *) ap_build_config(cmd_parms *parms,
                                         apr_pool_t *p, apr_pool_t *temp_pool,
                                         ap_directive_t **conftree)
{
    ap_directive_t *current = *conftree;
    ap_directive_t *curr_parent = NULL;
    char *l = apr_palloc (temp_pool, MAX_STRING_LEN);
    const char *errmsg;

    if (current != NULL) {
        while (current->next) {
            current = current->next;
        }
    }

    while (!(ap_cfg_getline(l, MAX_STRING_LEN, parms->config_file))) {
        errmsg = ap_build_config_sub(p, temp_pool, l, parms,
                                     &current, &curr_parent, conftree);
        if (errmsg != NULL)
            return errmsg;

        if (*conftree == NULL && curr_parent != NULL) {
            *conftree = curr_parent;
        }

        if (*conftree == NULL && current != NULL) {
            *conftree = current;
        }
    }

    if (curr_parent != NULL) {
        errmsg = "";

        while (curr_parent != NULL) {
            errmsg = apr_psprintf(p, "%s%s%s:%u: %s> was not closed.",
                                  errmsg,
                                  *errmsg == '\0' ? "" : APR_EOL_STR,
                                  curr_parent->filename,
                                  curr_parent->line_num,
                                  curr_parent->directive);

            parms->err_directive = curr_parent;
            curr_parent = curr_parent->parent;
        }

        return errmsg;
    }

    return NULL;
}

/*
 * Generic command functions...
 */

AP_DECLARE_NONSTD(const char *) ap_set_string_slot(cmd_parms *cmd,
                                                   void *struct_ptr,
                                                   const char *arg)
{
    int offset = (int)(long)cmd->info;

    *(const char **)((char *)struct_ptr + offset) = arg;

    return NULL;
}

AP_DECLARE_NONSTD(const char *) ap_set_int_slot(cmd_parms *cmd,
                                                void *struct_ptr,
                                                const char *arg)
{
    char *endptr;
    char *error_str = NULL;
    int offset = (int)(long)cmd->info;

    *(int *)((char*)struct_ptr + offset) = strtol(arg, &endptr, 10);

    if ((*arg == '\0') || (*endptr != '\0')) {
        error_str = apr_psprintf(cmd->pool,
                     "Invalid value for directive %s, expected integer",
                     cmd->directive->directive);
    }

    return error_str;
}

AP_DECLARE_NONSTD(const char *) ap_set_string_slot_lower(cmd_parms *cmd,
                                                         void *struct_ptr,
                                                         const char *arg_)
{
    char *arg = apr_pstrdup(cmd->pool,arg_);
    int offset = (int)(long)cmd->info;

    ap_str_tolower(arg);
    *(char **)((char *)struct_ptr + offset) = arg;

    return NULL;
}

AP_DECLARE_NONSTD(const char *) ap_set_flag_slot(cmd_parms *cmd,
                                                 void *struct_ptr_v, int arg)
{
    int offset = (int)(long)cmd->info;
    char *struct_ptr = (char *)struct_ptr_v;

    *(int *)(struct_ptr + offset) = arg ? 1 : 0;

    return NULL;
}

AP_DECLARE_NONSTD(const char *) ap_set_file_slot(cmd_parms *cmd, void *struct_ptr,
                                                 const char *arg)
{
    /* Prepend server_root to relative arg.
     * This allows most args to be independent of server_root,
     * so the server can be moved or mirrored with less pain.
     */
    const char *path;