[Asterisk-code-review] pbx variables.c: Misc fixes in variable substitution. (asterisk[13])
Richard Mudgett
asteriskteam at digium.com
Mon Jan 22 12:37:48 CST 2018
Richard Mudgett has uploaded this change for review. ( https://gerrit.asterisk.org/8038
Change subject: pbx_variables.c: Misc fixes in variable substitution.
......................................................................
pbx_variables.c: Misc fixes in variable substitution.
* Copy more than one character at a time when there is nothing to
substitute.
* Fix off by one error if a '}' or ']' is missing.
* Eliminated the requirement that the "used" parameter had to point to a
variable. The current callers were always declaring a variable to meet
the requirement and discarding the value put into that variable. Now it
can be NULL.
* In ast_str_substitute_variables_full() fixed using the bogus channel to
evaluate a function. We were not using the bogus channel we just created
to help evaluate a subexpression.
Change-Id: Ia83d99f4f16abe47f329eb39b6ff2013ae7c9854
---
M include/asterisk/pbx.h
M main/pbx_variables.c
2 files changed, 157 insertions(+), 90 deletions(-)
git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/38/8038/1
diff --git a/include/asterisk/pbx.h b/include/asterisk/pbx.h
index f177b09..6dea744 100644
--- a/include/asterisk/pbx.h
+++ b/include/asterisk/pbx.h
@@ -1378,7 +1378,7 @@
* \param c Channel variables from which to extract values, and channel to pass to any dialplan functions.
* \param headp If no channel is specified, a channel list from which to extract variable values
* \param templ Variable template to expand.
- * \param used Number of bytes read from the template.
+ * \param used Number of bytes read from the template. (May be NULL)
*/
void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, struct ast_channel *c, struct varshead *headp, const char *templ, size_t *used);
/*! @} */
diff --git a/main/pbx_variables.c b/main/pbx_variables.c
index 16ddbd0..f09540b 100644
--- a/main/pbx_variables.c
+++ b/main/pbx_variables.c
@@ -398,51 +398,74 @@
void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, struct ast_channel *c, struct varshead *headp, const char *templ, size_t *used)
{
/* Substitutes variables into buf, based on string templ */
- char *cp4 = NULL;
const char *whereweare;
- int orig_size = 0;
- int offset, offset2, isfunction;
- const char *nextvar, *nextexp, *nextthing;
- const char *vars, *vare;
- char *finalvars;
- int pos, brackets, needsub, len;
- struct ast_str *substr1 = ast_str_create(16), *substr2 = NULL, *substr3 = ast_str_create(16);
+ struct ast_str *substr1 = ast_str_create(16);
+ struct ast_str *substr2 = NULL;
+ struct ast_str *substr3 = ast_str_create(16);
ast_str_reset(*buf);
+
+ if (!substr1 || !substr3) {
+ if (used) {
+ *used = ast_str_strlen(*buf);
+ }
+ ast_free(substr1);
+ ast_free(substr3);
+ return;
+ }
+
whereweare = templ;
while (!ast_strlen_zero(whereweare)) {
+ const char *nextvar = NULL;
+ const char *nextexp = NULL;
+ const char *nextthing;
+ const char *vars;
+ const char *vare;
+ char *finalvars;
+ int pos;
+ int brackets;
+ int needsub;
+ int len;
+
/* reset our buffer */
ast_str_reset(substr3);
- /* Assume we're copying the whole remaining string */
- pos = strlen(whereweare);
- nextvar = NULL;
- nextexp = NULL;
+ /* Determine how much simply needs to be copied to the output buf. */
nextthing = strchr(whereweare, '$');
if (nextthing) {
+ pos = nextthing - whereweare;
switch (nextthing[1]) {
case '{':
+ /* Variable substitution */
nextvar = nextthing;
- pos = nextvar - whereweare;
break;
case '[':
+ /* Expression substitution */
nextexp = nextthing;
- pos = nextexp - whereweare;
break;
default:
- pos = 1;
+ /* '$' is not part of a substitution so include it too. */
+ ++pos;
+ break;
}
+ } else {
+ /* We're copying the whole remaining string */
+ pos = strlen(whereweare);
}
if (pos) {
/* Copy that many bytes */
ast_str_append_substr(buf, maxlen, whereweare, pos);
- templ += pos;
whereweare += pos;
}
if (nextvar) {
+ int offset;
+ int offset2;
+ int isfunction;
+ int res;
+
/* We have a variable. Find the start and end, and determine
if we are going to have to recursively call ourselves on the
contents */
@@ -454,33 +477,42 @@
while (brackets && *vare) {
if ((vare[0] == '$') && (vare[1] == '{')) {
needsub++;
+ brackets++;
+ vare++;
} else if (vare[0] == '{') {
brackets++;
} else if (vare[0] == '}') {
brackets--;
- } else if ((vare[0] == '$') && (vare[1] == '['))
+ } else if ((vare[0] == '$') && (vare[1] == '[')) {
needsub++;
+ vare++;
+ }
vare++;
}
- if (brackets)
+ len = vare - vars;
+ if (brackets) {
ast_log(LOG_WARNING, "Error in extension logic (missing '}')\n");
- len = vare - vars - 1;
+ } else {
+ /* Don't count the closing '}' in the length. */
+ --len;
+ }
/* Skip totally over variable string */
- whereweare += (len + 3);
+ whereweare = vare;
- /* Store variable name (and truncate) */
+ /* Store variable name expression to lookup. */
ast_str_set_substr(&substr1, 0, vars, len);
ast_debug(5, "Evaluating '%s' (from '%s' len %d)\n", ast_str_buffer(substr1), vars, len);
/* Substitute if necessary */
if (needsub) {
- size_t my_used;
-
if (!substr2) {
substr2 = ast_str_create(16);
+ if (!substr2) {
+ continue;
+ }
}
- ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), &my_used);
+ ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), NULL);
finalvars = ast_str_buffer(substr2);
} else {
finalvars = ast_str_buffer(substr1);
@@ -490,28 +522,32 @@
if (isfunction) {
/* Evaluate function */
if (c || !headp) {
- cp4 = ast_func_read2(c, finalvars, &substr3, 0) ? NULL : ast_str_buffer(substr3);
+ res = ast_func_read2(c, finalvars, &substr3, 0);
} else {
struct varshead old;
- struct ast_channel *bogus = ast_dummy_channel_alloc();
+ struct ast_channel *bogus;
+
+ bogus = ast_dummy_channel_alloc();
if (bogus) {
- memcpy(&old, ast_channel_varshead(bogus), sizeof(old));
- memcpy(ast_channel_varshead(bogus), headp, sizeof(*ast_channel_varshead(bogus)));
- cp4 = ast_func_read2(c, finalvars, &substr3, 0) ? NULL : ast_str_buffer(substr3);
+ old = *ast_channel_varshead(bogus);
+ *ast_channel_varshead(bogus) = *headp;
+ res = ast_func_read2(bogus, finalvars, &substr3, 0);
/* Don't deallocate the varshead that was passed in */
- memcpy(ast_channel_varshead(bogus), &old, sizeof(*ast_channel_varshead(bogus)));
+ *ast_channel_varshead(bogus) = old;
ast_channel_unref(bogus);
} else {
- ast_log(LOG_ERROR, "Unable to allocate bogus channel for variable substitution. Function results may be blank.\n");
+ ast_log(LOG_ERROR, "Unable to allocate bogus channel for function value substitution.\n");
+ res = -1;
}
}
- ast_debug(2, "Function %s result is '%s'\n", finalvars, cp4 ? cp4 : "(null)");
+ ast_debug(2, "Function %s result is '%s'\n",
+ finalvars, res ? "" : ast_str_buffer(substr3));
} else {
/* Retrieve variable value */
ast_str_retrieve_variable(&substr3, 0, c, headp, finalvars);
- cp4 = ast_str_buffer(substr3);
+ res = 0;
}
- if (cp4) {
+ if (!res) {
ast_str_substring(substr3, offset, offset2);
ast_str_append(buf, maxlen, "%s", ast_str_buffer(substr3));
}
@@ -539,24 +575,29 @@
}
vare++;
}
- if (brackets)
+ len = vare - vars;
+ if (brackets) {
ast_log(LOG_WARNING, "Error in extension logic (missing ']')\n");
- len = vare - vars - 1;
+ } else {
+ /* Don't count the closing ']' in the length. */
+ --len;
+ }
/* Skip totally over expression */
- whereweare += (len + 3);
+ whereweare = vare;
- /* Store variable name (and truncate) */
+ /* Store expression to evaluate. */
ast_str_set_substr(&substr1, 0, vars, len);
/* Substitute if necessary */
if (needsub) {
- size_t my_used;
-
if (!substr2) {
substr2 = ast_str_create(16);
+ if (!substr2) {
+ continue;
+ }
}
- ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), &my_used);
+ ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), NULL);
finalvars = ast_str_buffer(substr2);
} else {
finalvars = ast_str_buffer(substr1);
@@ -568,7 +609,9 @@
ast_str_append(buf, maxlen, "%s", ast_str_buffer(substr3));
}
}
- *used = ast_str_strlen(*buf) - orig_size;
+ if (used) {
+ *used = ast_str_strlen(*buf);
+ }
ast_free(substr1);
ast_free(substr2);
ast_free(substr3);
@@ -576,49 +619,58 @@
void ast_str_substitute_variables(struct ast_str **buf, ssize_t maxlen, struct ast_channel *chan, const char *templ)
{
- size_t used;
- ast_str_substitute_variables_full(buf, maxlen, chan, NULL, templ, &used);
+ ast_str_substitute_variables_full(buf, maxlen, chan, NULL, templ, NULL);
}
void ast_str_substitute_variables_varshead(struct ast_str **buf, ssize_t maxlen, struct varshead *headp, const char *templ)
{
- size_t used;
- ast_str_substitute_variables_full(buf, maxlen, NULL, headp, templ, &used);
+ ast_str_substitute_variables_full(buf, maxlen, NULL, headp, templ, NULL);
}
void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead *headp, const char *cp1, char *cp2, int count, size_t *used)
{
/* Substitutes variables into cp2, based on string cp1, cp2 NO LONGER NEEDS TO BE ZEROED OUT!!!! */
- char *cp4 = NULL;
- const char *whereweare, *orig_cp2 = cp2;
- int length, offset, offset2, isfunction;
+ const char *whereweare;
+ const char *orig_cp2 = cp2;
char *workspace = NULL;
- char *ltmp = NULL, *var = NULL;
- char *nextvar, *nextexp, *nextthing;
- char *vars, *vare;
- int pos, brackets, needsub, len;
+ char *ltmp = NULL;
+ char *var = NULL;
*cp2 = 0; /* just in case nothing ends up there */
whereweare = cp1;
while (!ast_strlen_zero(whereweare) && count) {
- /* Assume we're copying the whole remaining string */
- pos = strlen(whereweare);
- nextvar = NULL;
- nextexp = NULL;
+ char *nextvar = NULL;
+ char *nextexp = NULL;
+ char *nextthing;
+ char *vars;
+ char *vare;
+ int length;
+ int pos;
+ int brackets;
+ int needsub;
+ int len;
+
+ /* Determine how much simply needs to be copied to the output buf. */
nextthing = strchr(whereweare, '$');
if (nextthing) {
+ pos = nextthing - whereweare;
switch (nextthing[1]) {
case '{':
+ /* Variable substitution */
nextvar = nextthing;
- pos = nextvar - whereweare;
break;
case '[':
+ /* Expression substitution */
nextexp = nextthing;
- pos = nextexp - whereweare;
break;
default:
- pos = 1;
+ /* '$' is not part of a substitution so include it too. */
+ ++pos;
+ break;
}
+ } else {
+ /* We're copying the whole remaining string */
+ pos = strlen(whereweare);
}
if (pos) {
@@ -636,6 +688,11 @@
}
if (nextvar) {
+ int offset;
+ int offset2;
+ int isfunction;
+ char *cp4;
+
/* We have a variable. Find the start and end, and determine
if we are going to have to recursively call ourselves on the
contents */
@@ -647,35 +704,41 @@
while (brackets && *vare) {
if ((vare[0] == '$') && (vare[1] == '{')) {
needsub++;
+ brackets++;
+ vare++;
} else if (vare[0] == '{') {
brackets++;
} else if (vare[0] == '}') {
brackets--;
- } else if ((vare[0] == '$') && (vare[1] == '['))
+ } else if ((vare[0] == '$') && (vare[1] == '[')) {
needsub++;
+ vare++;
+ }
vare++;
}
- if (brackets)
+ len = vare - vars;
+ if (brackets) {
ast_log(LOG_WARNING, "Error in extension logic (missing '}')\n");
- len = vare - vars - 1;
+ } else {
+ /* Don't count the closing '}' in the length. */
+ --len;
+ }
/* Skip totally over variable string */
- whereweare += (len + 3);
+ whereweare = vare;
if (!var)
var = ast_alloca(VAR_BUF_SIZE);
- /* Store variable name (and truncate) */
+ /* Store variable name expression to lookup (and truncate). */
ast_copy_string(var, vars, len + 1);
/* Substitute if necessary */
if (needsub) {
- size_t my_used;
-
if (!ltmp) {
ltmp = ast_alloca(VAR_BUF_SIZE);
}
- pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, &my_used);
+ pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL);
vars = ltmp;
} else {
vars = var;
@@ -693,16 +756,19 @@
cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
else {
struct varshead old;
- struct ast_channel *c = ast_dummy_channel_alloc();
- if (c) {
- memcpy(&old, ast_channel_varshead(c), sizeof(old));
- memcpy(ast_channel_varshead(c), headp, sizeof(*ast_channel_varshead(c)));
- cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
+ struct ast_channel *bogus;
+
+ bogus = ast_dummy_channel_alloc();
+ if (bogus) {
+ old = *ast_channel_varshead(bogus);
+ *ast_channel_varshead(bogus) = *headp;
+ cp4 = ast_func_read(bogus, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
/* Don't deallocate the varshead that was passed in */
- memcpy(ast_channel_varshead(c), &old, sizeof(*ast_channel_varshead(c)));
- c = ast_channel_unref(c);
+ *ast_channel_varshead(bogus) = old;
+ ast_channel_unref(bogus);
} else {
- ast_log(LOG_ERROR, "Unable to allocate bogus channel for variable substitution. Function results may be blank.\n");
+ ast_log(LOG_ERROR, "Unable to allocate bogus channel for function value substitution.\n");
+ cp4 = NULL;
}
}
ast_debug(2, "Function %s result is '%s'\n", vars, cp4 ? cp4 : "(null)");
@@ -745,34 +811,35 @@
}
vare++;
}
- if (brackets)
+ len = vare - vars;
+ if (brackets) {
ast_log(LOG_WARNING, "Error in extension logic (missing ']')\n");
- len = vare - vars - 1;
+ } else {
+ /* Don't count the closing ']' in the length. */
+ --len;
+ }
/* Skip totally over expression */
- whereweare += (len + 3);
+ whereweare = vare;
if (!var)
var = ast_alloca(VAR_BUF_SIZE);
- /* Store variable name (and truncate) */
+ /* Store expression to evaluate (and truncate). */
ast_copy_string(var, vars, len + 1);
/* Substitute if necessary */
if (needsub) {
- size_t my_used;
-
if (!ltmp) {
ltmp = ast_alloca(VAR_BUF_SIZE);
}
- pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, &my_used);
+ pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, NULL);
vars = ltmp;
} else {
vars = var;
}
length = ast_expr(vars, cp2, count, c);
-
if (length) {
ast_debug(1, "Expression result is '%s'\n", cp2);
count -= length;
@@ -781,19 +848,19 @@
}
}
}
- *used = cp2 - orig_cp2;
+ if (used) {
+ *used = cp2 - orig_cp2;
+ }
}
void pbx_substitute_variables_helper(struct ast_channel *c, const char *cp1, char *cp2, int count)
{
- size_t used;
- pbx_substitute_variables_helper_full(c, (c) ? ast_channel_varshead(c) : NULL, cp1, cp2, count, &used);
+ pbx_substitute_variables_helper_full(c, (c) ? ast_channel_varshead(c) : NULL, cp1, cp2, count, NULL);
}
void pbx_substitute_variables_varshead(struct varshead *headp, const char *cp1, char *cp2, int count)
{
- size_t used;
- pbx_substitute_variables_helper_full(NULL, headp, cp1, cp2, count, &used);
+ pbx_substitute_variables_helper_full(NULL, headp, cp1, cp2, count, NULL);
}
/*! \brief CLI support for listing global variables in a parseable way */
--
To view, visit https://gerrit.asterisk.org/8038
To unsubscribe, visit https://gerrit.asterisk.org/settings
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia83d99f4f16abe47f329eb39b6ff2013ae7c9854
Gerrit-Change-Number: 8038
Gerrit-PatchSet: 1
Gerrit-Owner: Richard Mudgett <rmudgett at digium.com>
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