[Asterisk-code-review] func_evalexten: Extension evaluation function. (asterisk[master])
Friendly Automation
asteriskteam at digium.com
Wed Apr 27 03:15:52 CDT 2022
Friendly Automation has submitted this change. ( https://gerrit.asterisk.org/c/asterisk/+/16075 )
Change subject: func_evalexten: Extension evaluation function.
......................................................................
func_evalexten: Extension evaluation function.
This adds the EVAL_EXTEN function, which may be used to retrieve
the variable-substituted data at any extension.
ASTERISK-29486
Change-Id: Iad81019689674c9f4ac77d235f5d7234adbb1432
---
A doc/CHANGES-staging/func_evalexten.txt
A funcs/func_evalexten.c
M include/asterisk/pbx.h
M main/pbx.c
M main/pbx_variables.c
5 files changed, 219 insertions(+), 27 deletions(-)
Approvals:
Joshua Colp: Looks good to me, but someone else must approve
George Joseph: Looks good to me, approved
Friendly Automation: Approved for Submit
diff --git a/doc/CHANGES-staging/func_evalexten.txt b/doc/CHANGES-staging/func_evalexten.txt
new file mode 100644
index 0000000..f912bbe
--- /dev/null
+++ b/doc/CHANGES-staging/func_evalexten.txt
@@ -0,0 +1,4 @@
+Subject: func_evalexten
+
+This adds the EVAL_EXTEN function which may be
+used to evaluate data at dialplan extensions.
diff --git a/funcs/func_evalexten.c b/funcs/func_evalexten.c
new file mode 100644
index 0000000..6a7d28b
--- /dev/null
+++ b/funcs/func_evalexten.c
@@ -0,0 +1,147 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2021, Naveen Albert
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Dialplan extension evaluation function
+ *
+ * \author Naveen Albert <asterisk at phreaknet.org>
+ *
+ * \ingroup functions
+ */
+
+/*** MODULEINFO
+ <support_level>extended</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include "asterisk/module.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/utils.h"
+#include "asterisk/app.h"
+
+/*** DOCUMENTATION
+ <function name="EVAL_EXTEN" language="en_US">
+ <synopsis>
+ Evaluates the contents of a dialplan extension and returns it as a string.
+ </synopsis>
+ <syntax>
+ <parameter name="context" />
+ <parameter name="extensions" />
+ <parameter name="priority" required="true" />
+ </syntax>
+ <description>
+ <para>The EVAL_EXTEN function looks up a dialplan entry by context,extension,priority,
+ evaluates the contents of a Return statement to resolve any variable or function
+ references, and returns the result as a string.</para>
+ <para>You can use this function to create simple user-defined lookup tables or
+ user-defined functions.</para>
+ <example title="Custom dialplan functions">
+ [call-types]
+ exten => _1NNN,1,Return(internal)
+ exten => _NXXNXXXXXX,1,Return(external)
+
+ [udf]
+ exten => calleridlen,1,Return(${LEN(${CALLERID(num)})})
+
+ [default]
+ exten => _X!,1,Verbose(Call type ${EVAL_EXTEN(call-types,${EXTEN},1)} - ${EVAL_EXTEN(udf,calleridlen,1)})
+ </example>
+ <para>Any variables in the evaluated data will be resolved in the context of
+ that extension. For example, <literal>${EXTEN}</literal> would refer to the
+ EVAL_EXTEN extension, not the extension in the context invoking the function.
+ This behavior is similar to other applications, e.g. <literal>Gosub</literal>.</para>
+ <example title="Choosing which prompt to use">
+ same => n,Read(input,${EVAL_EXTEN(prompts,${CALLERID(num)},1)})
+
+ [prompts]
+ exten => _X!,1,Return(default)
+ exten => _20X,1,Return(welcome)
+ exten => _2XX,1,Return(${DB(promptsettings/${EXTEN})})
+ exten => _3XX,1,Return(${ODBC_MYFUNC(${EXTEN})})
+ </example>
+ <para>Extensions on which EVAL_EXTEN is invoked are not different from other
+ extensions. However, the application at that extension is not executed.
+ Only the application data is parsed and evaluated.</para>
+ <para>A limitation of this function is that the application at the specified
+ extension isn't actually executed, and thus unlike a Gosub, you can't pass
+ arguments in the EVAL_EXTEN function.</para>
+ </description>
+ <see-also>
+ <ref type="function">EVAL</ref>
+ </see-also>
+ </function>
+ ***/
+
+static int eval_exten_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+{
+ char *exten, *pri, *context, *parse;
+ int ipri;
+ char tmpbuf[len];
+
+ if (ast_strlen_zero(data)) {
+ ast_log(LOG_WARNING, "The EVAL_EXTEN function requires an extension\n");
+ return -1;
+ }
+
+ parse = ast_strdupa(data);
+ /* Split context,exten,pri */
+ context = strsep(&parse, ",");
+ exten = strsep(&parse, ",");
+ pri = strsep(&parse, ",");
+
+ if (pbx_parse_location(chan, &context, &exten, &pri, &ipri, NULL, NULL)) {
+ return -1;
+ }
+
+ if (ast_strlen_zero(exten) || ast_strlen_zero(context)) { /* only lock if we really need to */
+ ast_channel_lock(chan);
+ if (ast_strlen_zero(exten)) {
+ exten = ast_strdupa(ast_channel_exten(chan));
+ }
+ if (ast_strlen_zero(context)) {
+ context = ast_strdupa(ast_channel_context(chan));
+ }
+ ast_channel_unlock(chan);
+ }
+
+ if (ast_get_extension_data(tmpbuf, len, chan, context, exten, ipri)) {
+ return -1; /* EVAL_EXTEN failed */
+ }
+
+ pbx_substitute_variables_helper_full_location(chan, (chan) ? ast_channel_varshead(chan) : NULL, tmpbuf, buf, len, NULL, context, exten, ipri);
+
+ return 0;
+}
+
+static struct ast_custom_function eval_exten_function = {
+ .name = "EVAL_EXTEN",
+ .read = eval_exten_read,
+};
+
+static int unload_module(void)
+{
+ return ast_custom_function_unregister(&eval_exten_function);
+}
+
+static int load_module(void)
+{
+ return ast_custom_function_register(&eval_exten_function);
+}
+
+AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Extension evaluation function");
diff --git a/include/asterisk/pbx.h b/include/asterisk/pbx.h
index f5f0691..d531b44 100644
--- a/include/asterisk/pbx.h
+++ b/include/asterisk/pbx.h
@@ -1501,6 +1501,25 @@
*/
int ast_async_goto_if_exists(struct ast_channel *chan, const char *context, const char *exten, int priority);
+/*!
+ * \brief Parses a dialplan location into context, extension, priority
+ *
+ * \param chan Channel to execute on
+ * \param context Pointer to initial value for context.
+ * \param exten Pointer to initial value for exten.
+ * \param pri Pointer to initial value for pri
+ * \param ipri Pointer to integer value of priority
+ * \param mode Pointer to mode (or NULL if mode is not used)
+ * \param rest Pointer to buffer to capture rest of parsing (or NULL if not used)
+ *
+ * strsep should be used to initially populate context, exten, and pri prior
+ * to calling this function. All arguments are modified in place.
+ *
+ * \retval 0 success
+ * \retval non-zero failure
+ */
+int pbx_parse_location(struct ast_channel *chan, char **context, char **exten, char **pri, int *ipri, int *mode, char *rest);
+
struct ast_custom_function* ast_custom_function_find(const char *name);
/*!
diff --git a/main/pbx.c b/main/pbx.c
index 00c653f..1e08f23 100644
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -8826,6 +8826,47 @@
return __ast_goto_if_exists(chan, context, exten, priority, 1);
}
+int pbx_parse_location(struct ast_channel *chan, char **contextp, char **extenp, char **prip, int *ipri, int *mode, char *rest)
+{
+ char *context, *exten, *pri;
+ /* do the strsep before here, so we don't have to alloc and free */
+ if (!*extenp) {
+ /* Only a priority in this one */
+ *prip = *contextp;
+ *extenp = NULL;
+ *contextp = NULL;
+ } else if (!*prip) {
+ /* Only an extension and priority in this one */
+ *prip = *extenp;
+ *extenp = *contextp;
+ *contextp = NULL;
+ }
+ context = *contextp;
+ exten = *extenp;
+ pri = *prip;
+ if (mode) {
+ if (*pri == '+') {
+ *mode = 1;
+ pri++;
+ } else if (*pri == '-') {
+ *mode = -1;
+ pri++;
+ }
+ }
+ if ((rest && sscanf(pri, "%30d%1s", ipri, rest) != 1) || sscanf(pri, "%30d", ipri) != 1) {
+ *ipri = ast_findlabel_extension(chan, context ? context : ast_channel_context(chan),
+ exten ? exten : ast_channel_exten(chan), pri,
+ S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
+ if (*ipri < 1) {
+ ast_log(LOG_WARNING, "Priority '%s' must be a number > 0, or valid label\n", pri);
+ return -1;
+ } else if (mode) {
+ *mode = 0;
+ }
+ }
+ return 0;
+}
+
static int pbx_parseable_goto(struct ast_channel *chan, const char *goto_string, int async)
{
char *exten, *pri, *context;
@@ -8842,31 +8883,9 @@
context = strsep(&stringp, ","); /* guaranteed non-null */
exten = strsep(&stringp, ",");
pri = strsep(&stringp, ",");
- if (!exten) { /* Only a priority in this one */
- pri = context;
- exten = NULL;
- context = NULL;
- } else if (!pri) { /* Only an extension and priority in this one */
- pri = exten;
- exten = context;
- context = NULL;
- }
- if (*pri == '+') {
- mode = 1;
- pri++;
- } else if (*pri == '-') {
- mode = -1;
- pri++;
- }
- if (sscanf(pri, "%30d%1s", &ipri, rest) != 1) {
- ipri = ast_findlabel_extension(chan, context ? context : ast_channel_context(chan),
- exten ? exten : ast_channel_exten(chan), pri,
- S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
- if (ipri < 1) {
- ast_log(LOG_WARNING, "Priority '%s' must be a number > 0, or valid label\n", pri);
- return -1;
- } else
- mode = 0;
+
+ if (pbx_parse_location(chan, &context, &exten, &pri, &ipri, &mode, rest)) {
+ return -1;
}
/* At this point we have a priority and maybe an extension and a context */
diff --git a/main/pbx_variables.c b/main/pbx_variables.c
index a060bf5..1f78a59 100644
--- a/main/pbx_variables.c
+++ b/main/pbx_variables.c
@@ -736,7 +736,7 @@
/* Substitute if necessary */
if (needsub) {
- pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL);
+ pbx_substitute_variables_helper_full_location(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL, context, exten, pri);
vars = ltmp;
} else {
vars = var;
@@ -770,10 +770,13 @@
/* For dialplan location, if we were told what to substitute explicitly, use that instead */
if (exten && !strcmp(vars, "EXTEN")) {
ast_copy_string(workspace, exten, VAR_BUF_SIZE);
+ cp4 = workspace;
} else if (context && !strcmp(vars, "CONTEXT")) {
ast_copy_string(workspace, context, VAR_BUF_SIZE);
+ cp4 = workspace;
} else if (pri && !strcmp(vars, "PRIORITY")) {
snprintf(workspace, VAR_BUF_SIZE, "%d", pri);
+ cp4 = workspace;
} else {
pbx_retrieve_variable(c, vars, &cp4, workspace, VAR_BUF_SIZE, headp);
}
@@ -829,7 +832,7 @@
/* Substitute if necessary */
if (needsub) {
- pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL);
+ pbx_substitute_variables_helper_full_location(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL, context, exten, pri);
vars = ltmp;
} else {
vars = var;
--
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Gerrit-Project: asterisk
Gerrit-Branch: master
Gerrit-Change-Id: Iad81019689674c9f4ac77d235f5d7234adbb1432
Gerrit-Change-Number: 16075
Gerrit-PatchSet: 23
Gerrit-Owner: N A <mail at interlinked.x10host.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at sangoma.com>
Gerrit-Reviewer: N A <mail at interlinked.x10host.com>
Gerrit-Reviewer: Sarah Autumn <sarah at endlesstemple.org>
Gerrit-MessageType: merged
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