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author | russell <russell@f38db490-d61c-443f-a65b-d21fe96a405b> | 2008-03-28 22:52:02 +0000 |
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committer | russell <russell@f38db490-d61c-443f-a65b-d21fe96a405b> | 2008-03-28 22:52:02 +0000 |
commit | 98197a94a97c33f3a5b0f951d13fe0ecbcd92c8c (patch) | |
tree | 6641ee97c25084de42b2f33b8eed299b592bd399 | |
parent | 667187be08b1c7c155afbda3bcfa377fbfe73955 (diff) |
Merged revisions 111908-111909 via svnmerge from
https://origsvn.digium.com/svn/asterisk/trunk
........
r111908 | russell | 2008-03-28 17:45:43 -0500 (Fri, 28 Mar 2008) | 3 lines
Note a minor race condition that I noticed while reviewing Jeff's changes
to this code.
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r111909 | russell | 2008-03-28 17:50:46 -0500 (Fri, 28 Mar 2008) | 3 lines
Make some notes about common usage of pbx_builtin_getvar_helper() that is not
thread-safe.
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git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.0@111910 f38db490-d61c-443f-a65b-d21fe96a405b
-rw-r--r-- | doc/janitor-projects.txt | 12 | ||||
-rw-r--r-- | include/asterisk/pbx.h | 14 | ||||
-rw-r--r-- | main/dnsmgr.c | 5 |
3 files changed, 31 insertions, 0 deletions
diff --git a/doc/janitor-projects.txt b/doc/janitor-projects.txt index 9d89ef18c..b111204f0 100644 --- a/doc/janitor-projects.txt +++ b/doc/janitor-projects.txt @@ -1,3 +1,15 @@ + -- There a bunch of places where the result of pbx_builtin_getvar_helper() + gets stored and used. This is not threadsafe. This code should be replaced + with the following thread-safe version: + + const char *var; + + ast_channel_lock(chan); + if ((var = pbx_builtin_getvar_helper(chan, "MYVAR"))) { + var = ast_strdupa(var); + } + ast_channel_unlock(chan); + -- Convert all existing uses of astobj.h to astobj2.h -- (chan_sip already in progress in a branch) diff --git a/include/asterisk/pbx.h b/include/asterisk/pbx.h index 1ba9b0d70..1543de78d 100644 --- a/include/asterisk/pbx.h +++ b/include/asterisk/pbx.h @@ -806,6 +806,20 @@ int pbx_builtin_serialize_variables(struct ast_channel *chan, struct ast_str **b /*! * \note Will lock the channel. + * + * \note This function will return a pointer to the buffer inside the channel + * variable. This value should only be accessed with the channel locked. If + * the value needs to be kept around, it should be done by using the following + * thread-safe code: + * \code + * const char *var; + * + * ast_channel_lock(chan); + * if ((var = pbx_builtin_getvar_helper(chan, "MYVAR"))) { + * var = ast_strdupa(var); + * } + * ast_channel_unlock(chan); + * \endcode */ const char *pbx_builtin_getvar_helper(struct ast_channel *chan, const char *name); diff --git a/main/dnsmgr.c b/main/dnsmgr.c index 0989f6315..19fd1baa7 100644 --- a/main/dnsmgr.c +++ b/main/dnsmgr.c @@ -21,6 +21,11 @@ * \brief Background DNS update manager * * \author Kevin P. Fleming <kpfleming@digium.com> + * + * \bug There is a minor race condition. In the event that an IP address + * of a dnsmgr managed host changes, there is the potential for the consumer + * of that address to access the in_addr data at the same time that the dnsmgr + * thread is in the middle of updating it to the new address. */ #include "asterisk.h" |