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Merged revisions 88805 via svnmerge from

Browse Source 
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r88805 | russell | 2007-11-05 16:07:54 -0600 (Mon, 05 Nov 2007) | 12 lines

After seeing crashes related to channel variables, I went looking around at the
ways that channel variables are handled.  In general, they were not handled in
a thread-safe way.  The channel _must_ be locked when reading or writing from/to
the channel variable list.

What I have done to improve this situation is to make pbx_builtin_setvar_helper()
and friends lock the channel when doing their thing.  Asterisk API calls almost 
all lock the channel for you as necessary, but this family of functions did not.

(closes issue #10923, reported by atis)
(closes issue #11159, reported by 850t)

........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@88934 65c4cc65-6c06-0410-ace0-fbb531ad65f3
1.6.0
Russell Bryant 18 years ago
parent ed6e62a8e5
commit 9bfd82cec2
4 changed files with 62 additions and 47 deletions
Show Stats Download Patch File Download Diff File

18
channels/busy.h
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@ -1,21 +1,3 @@
/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2007, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* 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.
*/
/* busy.h: Generated from frequencies 480 and 620
by gentone. 400 samples */
static short busy[400] = {

18
channels/ringtone.h
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@ -1,21 +1,3 @@
/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2007, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* 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.
*/
/* ringtone.h: Generated from frequencies 440 and 480
by gentone. 200 samples */
static short ringtone[200] = {

25
include/asterisk/pbx.h
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@ -850,14 +850,39 @@ struct ast_ignorepat *ast_walk_context_ignorepats(struct ast_context *con,
struct ast_ignorepat *ip);
struct ast_sw *ast_walk_context_switches(struct ast_context *con, struct ast_sw *sw);
/*!
* \note Will lock the channel.
*/
int pbx_builtin_serialize_variables(struct ast_channel *chan, struct ast_str **buf);
/*!
* \note Will lock the channel.
*/
const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name);
/*!
* \note Will lock the channel.
*/
void pbx_builtin_pushvar_helper(struct ast_channel *chan, const char *name, const char *value);
/*!
* \note Will lock the channel.
*/
void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const char *value);
/*!
* \note Will lock the channel.
*/
void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, char *workspace, int workspacelen, struct varshead *headp);
void pbx_builtin_clear_globals(void);
/*!
* \note Will lock the channel.
*/
int pbx_builtin_setvar(struct ast_channel *chan, void *data);
int pbx_builtin_raise_exception(struct ast_channel *chan, void *data);
void pbx_substitute_variables_helper(struct ast_channel *c,const char *cp1,char *cp2,int count);
void pbx_substitute_variables_varshead(struct varshead *headp, const char *cp1, char *cp2, int count);

48
main/pbx.c
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@ -1187,6 +1187,7 @@ void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, c
struct varshead *places[2] = { headp, &globals }; /* list of places where we may look */
if (c) {
ast_channel_lock(c);
places[0] = &c->varshead;
}
/*
@ -1284,6 +1285,9 @@ void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, c
if (need_substring)
*ret = substring(*ret, offset, length, workspace, workspacelen);
}
if (c)
ast_channel_unlock(c);
}
static void exception_store_free(void *data)
@ -5913,6 +5917,8 @@ int pbx_builtin_serialize_variables(struct ast_channel *chan, struct ast_str **b
(*buf)->used = 0;
(*buf)->str[0] = '\0';
ast_channel_lock(chan);
AST_LIST_TRAVERSE(&chan->varshead, variables, entries) {
if ((var = ast_var_name(variables)) && (val = ast_var_value(variables))
/* && !ast_strlen_zero(var) && !ast_strlen_zero(val) */
@ -5926,6 +5932,8 @@ int pbx_builtin_serialize_variables(struct ast_channel *chan, struct ast_str **b
break;
}
ast_channel_unlock(chan);
return total;
}
@ -5938,8 +5946,11 @@ const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name
if (!name)
return NULL;
if (chan)
if (chan) {
ast_channel_lock(chan);
places[0] = &chan->varshead;
}
for (i = 0; i < 2; i++) {
if (!places[i])
@ -5958,6 +5969,9 @@ const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name
break;
}
if (chan)
ast_channel_unlock(chan);
return ret;
}
@ -5974,18 +5988,25 @@ void pbx_builtin_pushvar_helper(struct ast_channel *chan, const char *name, cons
return;
}
headp = (chan) ? &chan->varshead : &globals;
if (chan) {
ast_channel_lock(chan);
headp = &chan->varshead;
} else {
ast_rwlock_wrlock(&globalslock);
headp = &globals;
}
if (value) {
if (headp == &globals)
ast_verb(2, "Setting global variable '%s' to '%s'\n", name, value);
newvariable = ast_var_assign(name, value);
if (headp == &globals)
ast_rwlock_wrlock(&globalslock);
AST_LIST_INSERT_HEAD(headp, newvariable, entries);
if (headp == &globals)
ast_rwlock_unlock(&globalslock);
}
if (chan)
ast_channel_unlock(chan);
else
ast_rwlock_unlock(&globalslock);
}
void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const char *value)
@ -5994,7 +6015,6 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
struct varshead *headp;
const char *nametail = name;
/* XXX may need locking on the channel ? */
if (name[strlen(name) - 1] == ')') {
char *function = ast_strdupa(name);
@ -6002,7 +6022,13 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
return;
}
headp = (chan) ? &chan->varshead : &globals;
if (chan) {
ast_channel_lock(chan);
headp = &chan->varshead;
} else {
ast_rwlock_wrlock(&globalslock);
headp = &globals;
}
/* For comparison purposes, we have to strip leading underscores */
if (*nametail == '_') {
@ -6011,8 +6037,6 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
nametail++;
}
if (headp == &globals)
ast_rwlock_wrlock(&globalslock);
AST_LIST_TRAVERSE (headp, newvariable, entries) {
if (strcasecmp(ast_var_name(newvariable), nametail) == 0) {
/* there is already such a variable, delete it */
@ -6036,7 +6060,9 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
chan ? chan->uniqueid : "none");
}
if (headp == &globals)
if (chan)
ast_channel_unlock(chan);
else
ast_rwlock_unlock(&globalslock);
}

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