1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/*
* Copyright (c) 2002-2014 Balabit
* Copyright (c) 1998-2014 Balázs Scheidler
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* As an additional exemption you are allowed to compile & link against the
* OpenSSL libraries as published by the OpenSSL project. See the file
* COPYING for details.
*
*/
#include "cfg.h"
/*
* $(template <template-name> ...)
*
* This template function looks up <template-name> in the configuration
* and uses that format its result. The template name can either be a
* static or a dynamic reference.
*
* * static: means that we perform lookup at configuration read time
*
* * dynamic: the template name is actually a template (e.g.
* ${foobar}), its result are taken as the name of the template and
* that is looked up at runtime.
*
* Dynamic references are slower, but more flexible. syslog-ng uses the
* following algorithm to determine which one to use:
*
* * static: if the name of the template can be resolved at compile
* time, the binding becomes static.
*
* * dynamic: if static lookup fails and the template name contains at
* least one '$' character to indicate that it is actually a template.
*
* In case of dynamic we allow 2nd and further arguments which will be
* used as content if the lookup fails.
*
* Examples:
* $(template foobar) -> static binding
* $(template ${foobar}) -> dynamic binding
* $(template ${foobar} '$DATE $HOST $MSGHDR$MSG\n') -> dynamic binding with fallback
*
*/
typedef struct _TFTemplateState
{
TFSimpleFuncState super;
GlobalConfig *cfg;
LogTemplate *invoked_template;
} TFTemplateState;
static LogTemplate *
tf_template_lookup_invoked_template(TFTemplateState *state, GlobalConfig *cfg, const gchar *function_name,
GError **error)
{
return cfg_tree_lookup_template(&cfg->tree, function_name);
}
static const gchar *
tf_template_extract_invoked_template_name_from_args(gint argc, gchar *argv[])
{
if (argc >= 2 && strcmp(argv[0], "template") == 0)
return argv[1];
return NULL;
}
static gboolean
tf_template_statically_bound(TFTemplateState *state)
{
return state->invoked_template != NULL;
}
static gboolean
tf_template_dynamically_bound(TFTemplateState *state)
{
return !tf_template_statically_bound(state);
}
static gboolean
tf_template_prepare(LogTemplateFunction *self, gpointer s, LogTemplate *parent, gint argc, gchar *argv[],
GError **error)
{
TFTemplateState *state = (TFTemplateState *) s;
const gchar *invoked_template_name;
g_return_val_if_fail(error == NULL || *error == NULL, FALSE);
invoked_template_name = tf_template_extract_invoked_template_name_from_args(argc, argv);
if (!invoked_template_name)
{
g_set_error(error, LOG_TEMPLATE_ERROR, LOG_TEMPLATE_ERROR_COMPILE,
"$(template) requires one argument, that specifies the template name to be invoked");
return FALSE;
}
state->invoked_template = tf_template_lookup_invoked_template(state, parent->cfg, invoked_template_name, error);
if (tf_template_statically_bound(state))
return TRUE;
/* compile time lookup failed, let's check if it's a dynamically bound invocation */
if (strchr(invoked_template_name, '$') == NULL)
{
/* our argument is not a template, no chance of being better at
* runtime, raise as an error */
g_set_error(error, LOG_TEMPLATE_ERROR, LOG_TEMPLATE_ERROR_COMPILE,
"$(template) Unknown template function or template \"%s\"",
invoked_template_name);
return FALSE;
}
state->cfg = parent->cfg;
return tf_simple_func_prepare(self, s, parent, argc, argv, error);
}
static void
tf_template_eval(LogTemplateFunction *self, gpointer s, LogTemplateInvokeArgs *args)
{
TFTemplateState *state = (TFTemplateState *) s;
if (tf_template_dynamically_bound(state))
tf_simple_func_eval(self, s, args);
}
static LogTemplate *
tf_template_get_template_to_be_invoked(TFTemplateState *state, const LogTemplateInvokeArgs *args)
{
LogTemplate *invoked_template;
if (tf_template_dynamically_bound(state))
{
const gchar *template_name = args->argv[0]->str;
invoked_template = cfg_tree_lookup_template(&state->cfg->tree, template_name);
msg_trace("$(template) dynamic template lookup result",
evt_tag_str("template", template_name),
evt_tag_int("found", invoked_template != NULL));
}
else
{
invoked_template = log_template_ref(state->invoked_template);
}
return invoked_template;
}
static void
tf_template_call(LogTemplateFunction *self, gpointer s, const LogTemplateInvokeArgs *args, GString *result,
LogMessageValueType *type)
{
TFTemplateState *state = (TFTemplateState *) s;
LogTemplate *invoked_template = NULL;
invoked_template = tf_template_get_template_to_be_invoked(state, args);
if (!invoked_template)
{
*type = LM_VT_STRING;
_append_args_with_separator(state->super.argc - 1, (GString **) &args->argv[1], result, ' ');
return;
}
log_template_append_format_value_and_type_with_context(invoked_template, args->messages, args->num_messages,
args->options, result, type);
log_template_unref(invoked_template);
}
static void
tf_template_free_state(gpointer s)
{
TFTemplateState *state = (TFTemplateState *) s;
log_template_unref(state->invoked_template);
tf_simple_func_free_state(s);
}
TEMPLATE_FUNCTION(TFTemplateState, tf_template,
tf_template_prepare, tf_template_eval, tf_template_call, tf_template_free_state,
NULL);
|
