postconf_user.c

[詳解]

/*++
/* NAME
/*  postconf_user 3
/* SUMMARY
/*  support for user-defined main.cf parameter names
/* SYNOPSIS
/*  #include <postconf.h>
/*
/*  void    pcf_register_user_parameters()
/* DESCRIPTION
/*  Postfix has multiple parameter name spaces: the global
/*  main.cf parameter name space, and the local parameter name
/*  space of each master.cf entry. Parameters in local name
/*  spaces take precedence over global parameters.
/*
/*  There are three categories of known parameter names: built-in,
/*  service-defined (see postconf_service.c), and valid
/*  user-defined.
/*
/*  There are two categories of valid user-defined parameter
/*  names:
/*
/*  - Parameters whose user-defined-name appears in the value
/*  of smtpd_restriction_classes in main.cf or master.cf.
/*
/*  - Parameters whose $user-defined-name appear in the value
/*  of "name=value" entries in main.cf or master.cf.
/*
/*  - In both cases the parameters must have a
/*  "user-defined-name=value" entry in main.cf or master.cf.
/*
/*  Other user-defined parameter names are flagged as "unused".
/*
/*  pcf_register_user_parameters() scans the global and per-service
/*  name spaces for user-defined parameters and flags parameters
/*  as "valid" in the global name space (pcf_param_table) or
/*  in the per-service name space (valid_params).
/*
/*  This function also invokes pcf_register_dbms_parameters() to
/*  to instantiate legacy per-dbms parameters, and to examine
/*  per-dbms configuration files. This is limited to the content
/*  of global and local, built-in and per-service, parameters.
/* DIAGNOSTICS
/*  Problems are reported to the standard error stream.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*
/*  Wietse Venema
/*  Google, Inc.
/*  111 8th Avenue
/*  New York, NY 10011, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <string.h>

/* Utility library. */

#include <msg.h>
#include <mymalloc.h>
#include <htable.h>
#include <mac_expand.h>
#include <stringops.h>

/* Global library. */

#include <mail_conf.h>
#include <mail_params.h>

/* Application-specific. */

#include <postconf.h>

 /*
  * Hash with all user-defined names in the global smtpd_restriction_classes
  * value. This is used when validating "-o user-defined-name=value" entries
  * in master.cf.
  */
static HTABLE *pcf_rest_class_table;

 /*
  * SLMs.
  */
#define STR(x)  vstring_str(x)

 /*
  * Macros to make code with obscure constants more readable.
  */
#define NO_SCAN_RESULT  ((VSTRING *) 0)
#define NO_SCAN_FILTER  ((char *) 0)

/* SCAN_USER_PARAMETER_VALUE - examine macro names in parameter value */

#define SCAN_USER_PARAMETER_VALUE(value, class, scope) do { \
    PCF_PARAM_CTX _ctx; \
    _ctx.local_scope = (scope); \
    _ctx.param_class = (class); \
    (void) mac_expand(NO_SCAN_RESULT, (value), MAC_EXP_FLAG_SCAN, \
        NO_SCAN_FILTER, pcf_flag_user_parameter_wrapper, (void *) &_ctx); \
} while (0)

/* pcf_convert_user_parameter - get user-defined parameter string value */

static const char *pcf_convert_user_parameter(void *unused_ptr)
{
    return ("");            /* can't happen */
}

/* pcf_flag_user_parameter - flag user-defined name "valid" if it has name=value */

static const char *pcf_flag_user_parameter(const char *mac_name,
                               int param_class,
                            PCF_MASTER_ENT *local_scope)
{
    const char *source = local_scope ? MASTER_CONF_FILE : MAIN_CONF_FILE;
    int     user_supplied = 0;

    /*
     * If the name=value exists in the local (or global) name space, update
     * the local (or global) "valid" parameter name table.
     * 
     * Do not "validate" user-defined parameters whose name appears only as
     * macro expansion; this is how Postfix historically implements backwards
     * compatibility after a feature name change.
     */
    if (local_scope && dict_get(local_scope->all_params, mac_name)) {
    user_supplied = 1;
    /* $name in master.cf references name=value in master.cf. */
    if (PCF_PARAM_TABLE_LOCATE(local_scope->valid_names, mac_name) == 0) {
        PCF_PARAM_TABLE_ENTER(local_scope->valid_names, mac_name,
                  param_class, PCF_PARAM_NO_DATA,
                  pcf_convert_user_parameter);
        if (msg_verbose)
        msg_info("$%s in %s:%s validates %s=value in %s:%s",
             mac_name, MASTER_CONF_FILE,
             local_scope->name_space,
             mac_name, MASTER_CONF_FILE,
             local_scope->name_space);
    }
    } else if (mail_conf_lookup(mac_name) != 0) {
    user_supplied = 1;
    /* $name in main/master.cf references name=value in main.cf. */
    if (PCF_PARAM_TABLE_LOCATE(pcf_param_table, mac_name) == 0) {
        PCF_PARAM_TABLE_ENTER(pcf_param_table, mac_name, param_class,
                 PCF_PARAM_NO_DATA, pcf_convert_user_parameter);
        if (msg_verbose) {
        if (local_scope)
            msg_info("$%s in %s:%s validates %s=value in %s",
                 mac_name, MASTER_CONF_FILE,
                 local_scope->name_space,
                 mac_name, MAIN_CONF_FILE);
        else
            msg_info("$%s in %s validates %s=value in %s",
                 mac_name, MAIN_CONF_FILE,
                 mac_name, MAIN_CONF_FILE);
        }
    }
    }
    if (local_scope == 0) {
    for (local_scope = pcf_master_table; local_scope->argv; local_scope++) {
        if (local_scope->all_params != 0
        && dict_get(local_scope->all_params, mac_name) != 0) {
        user_supplied = 1;
        /* $name in main.cf references name=value in master.cf. */
        if (PCF_PARAM_TABLE_LOCATE(local_scope->valid_names, mac_name) == 0) {
            PCF_PARAM_TABLE_ENTER(local_scope->valid_names, mac_name,
                      param_class, PCF_PARAM_NO_DATA,
                      pcf_convert_user_parameter);
            if (msg_verbose)
            msg_info("$%s in %s validates %s=value in %s:%s",
                 mac_name, MAIN_CONF_FILE,
                 mac_name, MASTER_CONF_FILE,
                 local_scope->name_space);
        }
        }
    }
    }

    /*
     * Warn about a $name that has no user-supplied explicit value or
     * Postfix-supplied default value. We don't enforce this for legacy DBMS
     * parameters because they exist only for backwards compatibility, so we
     * don't bother to figure out which parameters come without defaults.
     */
    if (user_supplied == 0 && (param_class & PCF_PARAM_FLAG_DBMS) == 0
    && PCF_PARAM_TABLE_LOCATE(pcf_param_table, mac_name) == 0)
    msg_warn("%s/%s: undefined parameter: %s",
         var_config_dir, source, mac_name);
    return (0);
}

/* pcf_flag_user_parameter_wrapper - mac_expand call-back helper */

static const char *pcf_flag_user_parameter_wrapper(const char *mac_name,
                                   int unused_mode,
                                   void *context)
{
    PCF_PARAM_CTX *ctx = (PCF_PARAM_CTX *) context;

    return (pcf_flag_user_parameter(mac_name, ctx->param_class, ctx->local_scope));
}

/* pcf_lookup_eval - generalized mail_conf_lookup_eval */

static const char *pcf_lookup_eval(const char *dict_name, const char *name)
{
    const char *value;

#define RECURSIVE       1

    if ((value = dict_lookup(dict_name, name)) != 0)
    value = dict_eval(dict_name, value, RECURSIVE);
    return (value);
}

/* pcf_scan_user_parameter_namespace - scan parameters in name space */

static void pcf_scan_user_parameter_namespace(const char *dict_name,
                            PCF_MASTER_ENT *local_scope)
{
    const char *myname = "pcf_scan_user_parameter_namespace";
    const char *class_list;
    char   *saved_class_list;
    char   *cp;
    DICT   *dict;
    char   *param_name;
    int     how;
    const char *cparam_name;
    const char *cparam_value;
    PCF_PARAM_NODE *node;
    const char *source = local_scope ? MASTER_CONF_FILE : MAIN_CONF_FILE;

    /*
     * Flag parameter names in smtpd_restriction_classes as "valid", but only
     * if they have a "name=value" entry. If we are in not in a local name
     * space, update the global restriction class name table, so that we can
     * query the global table from within a local master.cf name space.
     */
    if ((class_list = pcf_lookup_eval(dict_name, VAR_REST_CLASSES)) != 0) {
    cp = saved_class_list = mystrdup(class_list);
    while ((param_name = mystrtok(&cp, CHARS_COMMA_SP)) != 0) {
        if (local_scope == 0
        && htable_locate(pcf_rest_class_table, param_name) == 0)
        htable_enter(pcf_rest_class_table, param_name, "");
        pcf_flag_user_parameter(param_name, PCF_PARAM_FLAG_USER, local_scope);
    }
    myfree(saved_class_list);
    }

    /*
     * For all "name=value" instances: a) if the name space is local and the
     * name appears in the global restriction class table, flag the name as
     * "valid" in the local name space; b) scan the value for macro
     * expansions of unknown parameter names, and flag those parameter names
     * as "valid" if they have a "name=value" entry.
     * 
     * We delete name=value entries for read-only parameters, to maintain
     * compatibility with Postfix programs that ignore such settings.
     */
    if ((dict = dict_handle(dict_name)) == 0)
    msg_panic("%s: parameter dictionary %s not found",
          myname, dict_name);
    if (dict->sequence == 0)
    msg_panic("%s: parameter dictionary %s has no iterator",
          myname, dict_name);
    for (how = DICT_SEQ_FUN_FIRST;
     dict->sequence(dict, how, &cparam_name, &cparam_value) == 0;
     how = DICT_SEQ_FUN_NEXT) {
    if (local_scope != 0
    && PCF_PARAM_TABLE_LOCATE(local_scope->valid_names, cparam_name) == 0
        && htable_locate(pcf_rest_class_table, cparam_name) != 0)
        PCF_PARAM_TABLE_ENTER(local_scope->valid_names, cparam_name,
                  PCF_PARAM_FLAG_USER, PCF_PARAM_NO_DATA,
                  pcf_convert_user_parameter);
    if ((node = PCF_PARAM_TABLE_FIND(pcf_param_table, cparam_name)) != 0) {
        if (PCF_READONLY_PARAMETER(node)) {
        msg_warn("%s/%s: read-only parameter assignment: %s=%s",
             var_config_dir, source, cparam_name, cparam_value);
        /* Can't use dict_del() with Postfix<2.10 htable_sequence(). */
        if (dict_del(dict, cparam_name) != 0)
            msg_panic("%s: can't delete %s/%s parameter entry for %s",
                  myname, var_config_dir, source, cparam_name);
        continue;
        }
        /* Re-label legacy parameter as user-defined, so it's printed. */
        if (PCF_LEGACY_PARAMETER(node))
        PCF_PARAM_CLASS_OVERRIDE(node, PCF_PARAM_FLAG_USER);
        /* Skip "do not expand" parameters. */
        if (PCF_RAW_PARAMETER(node))
        continue;
    }
    SCAN_USER_PARAMETER_VALUE(cparam_value, PCF_PARAM_FLAG_USER, local_scope);
#ifdef LEGACY_DBMS_SUPPORT

    /*
     * Scan global or local parameters that are built-in or per-service
     * (when node == 0, the parameter doesn't exist in the global
     * namespace and therefore it can't be built-in or per-service).
     */
    if (node != 0
        && (PCF_BUILTIN_PARAMETER(node) || PCF_SERVICE_PARAMETER(node)))
        pcf_register_dbms_parameters(cparam_value, pcf_flag_user_parameter,
                     local_scope);
#endif
    }
}

/* pcf_scan_default_parameter_values - scan parameters at implicit defaults */

static void pcf_scan_default_parameter_values(HTABLE *valid_params,
                                  const char *dict_name,
                            PCF_MASTER_ENT *local_scope)
{
    const char *myname = "pcf_scan_default_parameter_values";
    PCF_PARAM_INFO **list;
    PCF_PARAM_INFO **ht;
    const char *param_value;

    list = PCF_PARAM_TABLE_LIST(valid_params);
    for (ht = list; *ht; ht++) {
    /* Skip "do not expand" parameters. */
    if (PCF_RAW_PARAMETER(PCF_PARAM_INFO_NODE(*ht)))
        continue;
    /* Skip parameters with a non-default value. */
    if (dict_lookup(dict_name, PCF_PARAM_INFO_NAME(*ht)))
        continue;
    if ((param_value = pcf_convert_param_node(PCF_SHOW_DEFS, PCF_PARAM_INFO_NAME(*ht),
                        PCF_PARAM_INFO_NODE(*ht))) == 0)
        msg_panic("%s: parameter %s has no default value",
              myname, PCF_PARAM_INFO_NAME(*ht));
    SCAN_USER_PARAMETER_VALUE(param_value, PCF_PARAM_FLAG_USER, local_scope);
    /* No need to scan default values for legacy DBMS configuration. */
    }
    myfree((void *) list);
}

/* pcf_register_user_parameters - add parameters with user-defined names */

void    pcf_register_user_parameters(void)
{
    const char *myname = "pcf_register_user_parameters";
    PCF_MASTER_ENT *masterp;
    ARGV   *argv;
    char   *arg;
    char   *aval;
    int     field;
    char   *saved_arg;
    char   *param_name;
    char   *param_value;
    DICT   *dict;

    /*
     * Sanity checks.
     */
    if (pcf_param_table == 0)
    msg_panic("%s: global parameter table is not initialized", myname);
    if (pcf_master_table == 0)
    msg_panic("%s: master table is not initialized", myname);
    if (pcf_rest_class_table != 0)
    msg_panic("%s: restriction class table is already initialized", myname);

    /*
     * Initialize the table with global restriction class names.
     */
    pcf_rest_class_table = htable_create(1);

    /*
     * Initialize the per-service parameter name spaces.
     */
    for (masterp = pcf_master_table; (argv = masterp->argv) != 0; masterp++) {
    for (field = PCF_MASTER_MIN_FIELDS; argv->argv[field] != 0; field++) {
        arg = argv->argv[field];
        if (arg[0] != '-' || strcmp(arg, "--") == 0)
        break;
        if (strchr(pcf_daemon_options_expecting_value, arg[1]) == 0
        || (aval = argv->argv[field + 1]) == 0)
        continue;
        if (strcmp(arg, "-o") == 0) {
        saved_arg = mystrdup(aval);
        if (split_nameval(saved_arg, &param_name, &param_value) == 0)
            dict_update(masterp->name_space, param_name, param_value);
        myfree(saved_arg);
        }
        field += 1;
    }
    if ((dict = dict_handle(masterp->name_space)) != 0) {
        masterp->all_params = dict;
        masterp->valid_names = htable_create(1);
    }
    }

    /*
     * Scan the "-o parameter=value" instances in each master.cf name space.
     */
    for (masterp = pcf_master_table; masterp->argv != 0; masterp++)
    if (masterp->all_params != 0)
        pcf_scan_user_parameter_namespace(masterp->name_space, masterp);

    /*
     * Scan parameter values that are left at their defaults in the global
     * name space. Some defaults contain the $name of an obsolete parameter
     * for backwards compatilility purposes. We might warn that an explicit
     * name=value is obsolete, but we must not warn that the parameter is
     * unused.
     */
    pcf_scan_default_parameter_values(pcf_param_table, CONFIG_DICT,
                      (PCF_MASTER_ENT *) 0);

    /*
     * Scan the explicit name=value entries in the global name space.
     */
    pcf_scan_user_parameter_namespace(CONFIG_DICT, (PCF_MASTER_ENT *) 0);
}