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@@ -1,40 +1,44 @@
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#$Id$
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#
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-# Module intialization description
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#
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# History
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#--------
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# 2007-06-07 created by Andrei Pelinescu <[email protected]>
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#
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+SIP-router Module intialization description
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+===========================================
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This document is a very brief overview on what possibilities are for a module
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-to run some initializations (or put in another way what's safe and what's
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+to run some initializations (or put in another way: What's safe and what's
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not safe to do in mod_init and mod_child_init).
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The interesting function are the mod_init (the init_f memeber of
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- the module_exports structure) and the mod_child_init (init_child_f in
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- module_exports) functions.
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+the module_exports structure) and the mod_child_init (init_child_f in
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+module_exports) functions.
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mod_init
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--------
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mod_init is called after parsing the config, loading all the modules and
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- going into daemon mode. mod_init is called in the main process context,
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- before changing the uid or gid (so if you want to do something requiring
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- higher privileges this is the place to do it). This is not the right place
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- to fork more ser processes, but instead is the only place where one can
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- register future forked processes (see register_procs()).
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+going into daemon mode. mod_init is called in the main process context,
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+before changing the uid or gid (so if you want to do something requiring
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+higher privileges this is the place to do it). This is not the right place
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+to fork more SIP-router processes, but instead is the only place where one can
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+register future forked processes (see register_procs()).
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+
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mod_init is ideal for initializing per process variables, assuming that you
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- don't need different values for each ser child (in which case see mod_child_init below) and shared memory variables assuming that you don't need ser's number of processes (which is not available at this point).
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+don't need different values for each SIP-router child (in which case see
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+mod_child_init below) and shared memory variables assuming that you don't
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+need SIP-router's number of processes (which is not available at this point).
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mod_child_init
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---------------
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-mod_child_init is called for each forked ser process with 2 exceptions:
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+mod_child_init is called for each forked SIP-router process with 2 exceptions:
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- it's called for the main process too and it's called twice
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- - it's not called for ser processes forked with PROC_NOCHLDINIT
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+ - it's not called for SIP-router processes forked with PROC_NOCHLDINIT
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mod_child_init is always called after mod_init. It takes one parameter, the
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process rank. This parameter can be used to differentiate between normal
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@@ -44,7 +48,7 @@ There are two very special rank values: PROC_INIT (as of 2007-06-06) and
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mod_child_init(PROC_INIT) is the first mod_child_init call made, and it's
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guaranteed to happen before any child process is forked. The process context
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is the "main" process (as for mod_init), but this time we have a little bit
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- more information: we know the number of ser processes. This is the right
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+ more information: we know the number of SIP-router processes. This is the right
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place to initialize things like shared arrays[get_max_procs()].
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Note also that everything done here will be inherited in all the future
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children processes (since it's executed in the "main" process context before
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@@ -52,14 +56,14 @@ Note also that everything done here will be inherited in all the future
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mod_child_init(PROC_MAIN) is another call that is done in the same "main"
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process context. This call happens just before initializing the main tcp
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- process. This is the only right place for forking more ser processes
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+ process. This is the only right place for forking more SIP-router processes
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(see fork_process()). WARNING: the context is the same "main" process as
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for mod_child_init(PROC_INIT) and mod_init() so care must be taken not to
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initialize things twice or three times for the "main" process.
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Except for the "main" process case mod_child_init(rank) will be called only
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once for each new child process, just after forking. A positive non-zero rank
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- means the current process is a normal ser process and a negative rank has
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+ means the current process is a normal SIP-router process and a negative rank has
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some special meaning (grep PROC_ sr_module.h for more info).
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mod_child_init(rank) is the best place for initializing per process variables,
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opening per process database connections, new sockets a.s.o. Note however
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@@ -72,15 +76,15 @@ mod_child_init(rank) is the best place for initializing per process variables,
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mod_child_init in the no-fork case
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----------------------------------
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-If ser is started in no-fork mode it will try to start as few processes as
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+If SIP-router is started in no-fork mode it will try to start as few processes as
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possible (as of this date it will start 3 processes the main process and the
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- 2 timers). In this case mod_child_init() will be called 3 times in the
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- same "main" process context: mod_child_init(PROC_INIT);
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- mod_child_init(PROC_MAIN) and mod_child_init(1) (since the first process is
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- also the "main" one).
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+2 timers). In this case mod_child_init() will be called 3 times in the
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+same "main" process context: mod_child_init(PROC_INIT);
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+mod_child_init(PROC_MAIN) and mod_child_init(1) (since the first process is
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+also the "main" one).
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-Forking new ser processes from a module
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+Forking new SIP-router processes from a module
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---------------------------------------
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static int mod_init()
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@@ -133,8 +137,9 @@ mod_child_init(PROC_INIT)
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process.
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mod_child_init(PROC_MAIN)
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- - the only place from where another ser process can be forked (see fork_process ()), but remember first to register the number of to-be-forked processes in
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- mod_init()
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+ - the only place from where another SIP-router process can be forked
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+ (see fork_process ()), but remember first to register the number of
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+ to-be-forked processes in mod_init()
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mod_child_init(rank!=PROC_INIT && rank!=PROC_MAIN)
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- initialize other per process variables (e.g. different values), whose
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oej