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pbx_variables.c: Misc fixes in variable substitution.

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* 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
This commit is contained in:
Richard Mudgett
2018-01-18 20:19:00 -06:00
parent 908e39f186
commit 2f78dc2bfa
2 changed files with 157 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/asterisk/pbx.h
View File

@@ -1432,7 +1432,7 @@ void ast_str_substitute_variables_varshead(struct ast_str **buf, ssize_t maxlen,
* \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);
/*! @} */

245
main/pbx_variables.c
View File

@@ -396,51 +396,74 @@ const char *ast_str_retrieve_variable(struct ast_str **str, ssize_t maxlen, stru
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 */
@@ -452,33 +475,42 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
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);
@@ -488,28 +520,32 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
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));
}
@@ -537,24 +573,29 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
}
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);
@@ -566,7 +607,9 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
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);
@@ -574,49 +617,58 @@ void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, str
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;
/* '$' is not part of a substitution so include it too. */
++pos;
break;
}
} else {
/* We're copying the whole remaining string */
pos = strlen(whereweare);
}
if (pos) {
@@ -634,6 +686,11 @@ void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead
}
if (nextvar) {
int offset;
int offset2;
int isfunction;
char *cp4;
/* We have a variable. Find the start and end, and determine
if we are going to have to recursively call ourselves on the
contents */
@@ -645,35 +702,41 @@ void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead
while (brackets && *vare) {
if ((vare[0] == '$') && (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;
@@ -691,16 +754,19 @@ void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead
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)");
@@ -743,34 +809,35 @@ void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead
}
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;
@@ -779,19 +846,19 @@ void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead
}
}
}
*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 */