postconf_lookup.c revision 1.2 
1/*	$NetBSD: postconf_lookup.c,v 1.2 2017/02/14 01:16:46 christos Exp $	*/
2
3/*++
4/* NAME
5/*	postconf_lookup 3
6/* SUMMARY
7/*	parameter lookup routines
8/* SYNOPSIS
9/*	#include <postconf.h>
10/*
11/*	const char *pcf_lookup_parameter_value(mode, name, local_scope, node)
12/*	int	mode;
13/*	const char *name;
14/*	PCF_MASTER_ENT *local_scope;
15/*	PCF_PARAM_NODE *node;
16/*
17/*	char    *pcf_expand_parameter_value(buf, mode, value, local_scope)
18/*	VSTRING *buf;
19/*	int	mode;
20/*	const char *value;
21/*	PCF_MASTER_ENT *local_scope;
22/* DESCRIPTION
23/*	These functions perform parameter value lookups.  The order
24/*	of decreasing precedence is:
25/* .IP \(bu
26/*	Search name=value parameter settings in master.cf.  These
27/*	lookups are disabled with the PCF_SHOW_DEFS flag.
28/* .IP \(bu
29/*	Search name=value parameter settings in main.cf.  These
30/*	lookups are disabled with the PCF_SHOW_DEFS flag.
31/* .IP \(bu
32/*	Search built-in default parameter settings. These lookups
33/*	are disabled with the PCF_SHOW_NONDEF flag.
34/* .PP
35/*	pcf_lookup_parameter_value() looks up the value for the
36/*	named parameter, and returns null if the name was not found.
37/*
38/*	pcf_expand_parameter_value() expands $name in the specified
39/*	parameter value. This function ignores the PCF_SHOW_NONDEF
40/*	flag.  The result value is a pointer to storage in a
41/*	user-supplied buffer, or in a buffer that is overwritten
42/*	with each call.
43/*
44/*	Arguments:
45/* .IP buf
46/*	Null buffer pointer, or pointer to user-supplied buffer.
47/* .IP mode
48/*	Bit-wise OR of zero or one of the following (other flags
49/*	are ignored):
50/* .RS
51/* .IP PCF_SHOW_DEFS
52/*	Search built-in default parameter settings only.
53/* .IP PCF_SHOW_NONDEF
54/*	Search local (master.cf) and global (main.cf) name=value
55/*	parameter settings only.
56/* .RE
57/* .IP name
58/*	The name of a parameter to be looked up.
59/* .IP value
60/*	The parameter value where $name should be expanded.
61/* .IP local_scope
62/*	Pointer to master.cf entry with local name=value settings,
63/*	or a null pointer (i.e. no local parameter lookup).
64/* .IP node
65/*	Global default value for the named parameter, or a null
66/*	pointer (i.e. do the global default lookup anyway).
67/* DIAGNOSTICS
68/*	Problems are reported to the standard error stream.
69/* LICENSE
70/* .ad
71/* .fi
72/*	The Secure Mailer license must be distributed with this software.
73/* AUTHOR(S)
74/*	Wietse Venema
75/*	IBM T.J. Watson Research
76/*	P.O. Box 704
77/*	Yorktown Heights, NY 10598, USA
78/*--*/
79
80/* System library. */
81
82#include <sys_defs.h>
83#include <string.h>
84
85/* Utility library. */
86
87#include <msg.h>
88#include <mymalloc.h>
89#include <vstring.h>
90#include <dict.h>
91#include <stringops.h>
92#include <mac_expand.h>
93
94/* Global library. */
95
96#include <mail_conf.h>
97
98/* Application-specific. */
99
100#include <postconf.h>
101
102#define STR(x) vstring_str(x)
103
104/* pcf_lookup_parameter_value - look up specific parameter value */
105
106const char *pcf_lookup_parameter_value(int mode, const char *name,
107				               PCF_MASTER_ENT *local_scope,
108				               PCF_PARAM_NODE *node)
109{
110    const char *value = 0;
111
112    /*
113     * Local name=value entries in master.cf take precedence over global
114     * name=value entries in main.cf. Built-in defaults have the lowest
115     * precedence.
116     */
117    if ((mode & PCF_SHOW_DEFS) != 0
118	|| ((local_scope == 0 || local_scope->all_params == 0
119	     || (value = dict_get(local_scope->all_params, name)) == 0)
120	    && (value = dict_lookup(CONFIG_DICT, name)) == 0
121	    && (mode & PCF_SHOW_NONDEF) == 0)) {
122	if (node != 0 || (node = PCF_PARAM_TABLE_FIND(pcf_param_table, name)) != 0)
123	    value = pcf_convert_param_node(PCF_SHOW_DEFS, name, node);
124    }
125    return (value);
126}
127
128 /*
129  * Data structure to pass private state while recursively expanding $name in
130  * parameter values.
131  */
132typedef struct {
133    int     mode;
134    PCF_MASTER_ENT *local_scope;
135} PCF_EVAL_CTX;
136
137/* pcf_lookup_parameter_value_wrapper - macro parser call-back routine */
138
139static const char *pcf_lookup_parameter_value_wrapper(const char *key,
140						            int unused_type,
141						              void *context)
142{
143    PCF_EVAL_CTX *cp = (PCF_EVAL_CTX *) context;
144
145    return (pcf_lookup_parameter_value(cp->mode, key, cp->local_scope,
146				       (PCF_PARAM_NODE *) 0));
147}
148
149/* pcf_expand_parameter_value - expand $name in parameter value */
150
151char   *pcf_expand_parameter_value(VSTRING *buf, int mode, const char *value,
152				           PCF_MASTER_ENT *local_scope)
153{
154    const char *myname = "pcf_expand_parameter_value";
155    static VSTRING *local_buf;
156    int     status;
157    PCF_EVAL_CTX eval_ctx;
158
159    /*
160     * Initialize.
161     */
162    if (buf == 0) {
163	if (local_buf == 0)
164	    local_buf = vstring_alloc(10);
165	buf = local_buf;
166    }
167
168    /*
169     * Expand macros recursively.
170     *
171     * When expanding $name in "postconf -n" parameter values, don't limit the
172     * search to only non-default parameter values.
173     *
174     * When expanding $name in "postconf -d" parameter values, do limit the
175     * search to only default parameter values.
176     */
177#define DONT_FILTER (char *) 0
178
179    eval_ctx.mode = (mode & ~PCF_SHOW_NONDEF);
180    eval_ctx.local_scope = local_scope;
181    status = mac_expand(buf, value, MAC_EXP_FLAG_RECURSE, DONT_FILTER,
182		    pcf_lookup_parameter_value_wrapper, (void *) &eval_ctx);
183    if (status & MAC_PARSE_ERROR)
184	msg_fatal("macro processing error");
185    if (msg_verbose > 1) {
186	if (strcmp(value, STR(buf)) != 0)
187	    msg_info("%s: expand %s -> %s", myname, value, STR(buf));
188	else
189	    msg_info("%s: const  %s", myname, value);
190    }
191    return (STR(buf));
192}
193