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diff --git a/docs/manual/developer/API.html b/docs/manual/developer/API.html deleted file mode 100644 index 496be760c9..0000000000 --- a/docs/manual/developer/API.html +++ /dev/null @@ -1,1161 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<HTML><HEAD> -<TITLE>Apache API notes</TITLE> -</HEAD> -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> -<!--#include virtual="header.html" --> - -<blockquote><strong>Warning:</strong> -This document has not been updated to take into account changes -made in the 2.0 version of the Apache HTTP Server. Some of the -information may still be relevant, but please use it -with care. -</blockquote> - -<H1 ALIGN="CENTER">Apache API notes</H1> - -These are some notes on the Apache API and the data structures you -have to deal with, <EM>etc.</EM> They are not yet nearly complete, but -hopefully, they will help you get your bearings. Keep in mind that -the API is still subject to change as we gain experience with it. -(See the TODO file for what <EM>might</EM> be coming). However, -it will be easy to adapt modules to any changes that are made. -(We have more modules to adapt than you do). -<P> - -A few notes on general pedagogical style here. In the interest of -conciseness, all structure declarations here are incomplete --- the -real ones have more slots that I'm not telling you about. For the -most part, these are reserved to one component of the server core or -another, and should be altered by modules with caution. However, in -some cases, they really are things I just haven't gotten around to -yet. Welcome to the bleeding edge.<P> - -Finally, here's an outline, to give you some bare idea of what's -coming up, and in what order: - -<UL> -<LI> <A HREF="#basics">Basic concepts.</A> -<MENU> - <LI> <A HREF="#HMR">Handlers, Modules, and Requests</A> - <LI> <A HREF="#moduletour">A brief tour of a module</A> -</MENU> -<LI> <A HREF="#handlers">How handlers work</A> -<MENU> - <LI> <A HREF="#req_tour">A brief tour of the <CODE>request_rec</CODE></A> - <LI> <A HREF="#req_orig">Where request_rec structures come from</A> - <LI> <A HREF="#req_return">Handling requests, declining, and returning error - codes</A> - <LI> <A HREF="#resp_handlers">Special considerations for response handlers</A> - <LI> <A HREF="#auth_handlers">Special considerations for authentication - handlers</A> - <LI> <A HREF="#log_handlers">Special considerations for logging handlers</A> -</MENU> -<LI> <A HREF="#pools">Resource allocation and resource pools</A> -<LI> <A HREF="#config">Configuration, commands and the like</A> -<MENU> - <LI> <A HREF="#per-dir">Per-directory configuration structures</A> - <LI> <A HREF="#commands">Command handling</A> - <LI> <A HREF="#servconf">Side notes --- per-server configuration, - virtual servers, <EM>etc</EM>.</A> -</MENU> -</UL> - -<H2><A NAME="basics">Basic concepts.</A></H2> - -We begin with an overview of the basic concepts behind the -API, and how they are manifested in the code. - -<H3><A NAME="HMR">Handlers, Modules, and Requests</A></H3> - -Apache breaks down request handling into a series of steps, more or -less the same way the Netscape server API does (although this API has -a few more stages than NetSite does, as hooks for stuff I thought -might be useful in the future). These are: - -<UL> - <LI> URI -> Filename translation - <LI> Auth ID checking [is the user who they say they are?] - <LI> Auth access checking [is the user authorized <EM>here</EM>?] - <LI> Access checking other than auth - <LI> Determining MIME type of the object requested - <LI> `Fixups' --- there aren't any of these yet, but the phase is - intended as a hook for possible extensions like - <CODE>SetEnv</CODE>, which don't really fit well elsewhere. - <LI> Actually sending a response back to the client. - <LI> Logging the request -</UL> - -These phases are handled by looking at each of a succession of -<EM>modules</EM>, looking to see if each of them has a handler for the -phase, and attempting invoking it if so. The handler can typically do -one of three things: - -<UL> - <LI> <EM>Handle</EM> the request, and indicate that it has done so - by returning the magic constant <CODE>OK</CODE>. - <LI> <EM>Decline</EM> to handle the request, by returning the magic - integer constant <CODE>DECLINED</CODE>. In this case, the - server behaves in all respects as if the handler simply hadn't - been there. - <LI> Signal an error, by returning one of the HTTP error codes. - This terminates normal handling of the request, although an - ErrorDocument may be invoked to try to mop up, and it will be - logged in any case. -</UL> - -Most phases are terminated by the first module that handles them; -however, for logging, `fixups', and non-access authentication -checking, all handlers always run (barring an error). Also, the -response phase is unique in that modules may declare multiple handlers -for it, via a dispatch table keyed on the MIME type of the requested -object. Modules may declare a response-phase handler which can handle -<EM>any</EM> request, by giving it the key <CODE>*/*</CODE> (<EM>i.e.</EM>, a -wildcard MIME type specification). However, wildcard handlers are -only invoked if the server has already tried and failed to find a more -specific response handler for the MIME type of the requested object -(either none existed, or they all declined).<P> - -The handlers themselves are functions of one argument (a -<CODE>request_rec</CODE> structure. vide infra), which returns an -integer, as above.<P> - -<H3><A NAME="moduletour">A brief tour of a module</A></H3> - -At this point, we need to explain the structure of a module. Our -candidate will be one of the messier ones, the CGI module --- this -handles both CGI scripts and the <CODE>ScriptAlias</CODE> config file -command. It's actually a great deal more complicated than most -modules, but if we're going to have only one example, it might as well -be the one with its fingers in every place.<P> - -Let's begin with handlers. In order to handle the CGI scripts, the -module declares a response handler for them. Because of -<CODE>ScriptAlias</CODE>, it also has handlers for the name -translation phase (to recognize <CODE>ScriptAlias</CODE>ed URIs), the -type-checking phase (any <CODE>ScriptAlias</CODE>ed request is typed -as a CGI script).<P> - -The module needs to maintain some per (virtual) -server information, namely, the <CODE>ScriptAlias</CODE>es in effect; -the module structure therefore contains pointers to a functions which -builds these structures, and to another which combines two of them (in -case the main server and a virtual server both have -<CODE>ScriptAlias</CODE>es declared).<P> - -Finally, this module contains code to handle the -<CODE>ScriptAlias</CODE> command itself. This particular module only -declares one command, but there could be more, so modules have -<EM>command tables</EM> which declare their commands, and describe -where they are permitted, and how they are to be invoked. <P> - -A final note on the declared types of the arguments of some of these -commands: a <CODE>pool</CODE> is a pointer to a <EM>resource pool</EM> -structure; these are used by the server to keep track of the memory -which has been allocated, files opened, <EM>etc.</EM>, either to service a -particular request, or to handle the process of configuring itself. -That way, when the request is over (or, for the configuration pool, -when the server is restarting), the memory can be freed, and the files -closed, <EM>en masse</EM>, without anyone having to write explicit code to -track them all down and dispose of them. Also, a -<CODE>cmd_parms</CODE> structure contains various information about -the config file being read, and other status information, which is -sometimes of use to the function which processes a config-file command -(such as <CODE>ScriptAlias</CODE>). - -With no further ado, the module itself: - -<PRE> -/* Declarations of handlers. */ - -int translate_scriptalias (request_rec *); -int type_scriptalias (request_rec *); -int cgi_handler (request_rec *); - -/* Subsidiary dispatch table for response-phase handlers, by MIME type */ - -handler_rec cgi_handlers[] = { -{ "application/x-httpd-cgi", cgi_handler }, -{ NULL } -}; - -/* Declarations of routines to manipulate the module's configuration - * info. Note that these are returned, and passed in, as void *'s; - * the server core keeps track of them, but it doesn't, and can't, - * know their internal structure. - */ - -void *make_cgi_server_config (pool *); -void *merge_cgi_server_config (pool *, void *, void *); - -/* Declarations of routines to handle config-file commands */ - -extern char *script_alias(cmd_parms *, void *per_dir_config, char *fake, - char *real); - -command_rec cgi_cmds[] = { -{ "ScriptAlias", script_alias, NULL, RSRC_CONF, TAKE2, - "a fakename and a realname"}, -{ NULL } -}; - -module cgi_module = { - STANDARD_MODULE_STUFF, - NULL, /* initializer */ - NULL, /* dir config creator */ - NULL, /* dir merger --- default is to override */ - make_cgi_server_config, /* server config */ - merge_cgi_server_config, /* merge server config */ - cgi_cmds, /* command table */ - cgi_handlers, /* handlers */ - translate_scriptalias, /* filename translation */ - NULL, /* check_user_id */ - NULL, /* check auth */ - NULL, /* check access */ - type_scriptalias, /* type_checker */ - NULL, /* fixups */ - NULL, /* logger */ - NULL /* header parser */ -}; -</PRE> - -<H2><A NAME="handlers">How handlers work</A></H2> - -The sole argument to handlers is a <CODE>request_rec</CODE> structure. -This structure describes a particular request which has been made to -the server, on behalf of a client. In most cases, each connection to -the client generates only one <CODE>request_rec</CODE> structure.<P> - -<H3><A NAME="req_tour">A brief tour of the <CODE>request_rec</CODE></A></H3> - -The <CODE>request_rec</CODE> contains pointers to a resource pool -which will be cleared when the server is finished handling the -request; to structures containing per-server and per-connection -information, and most importantly, information on the request itself.<P> - -The most important such information is a small set of character -strings describing attributes of the object being requested, including -its URI, filename, content-type and content-encoding (these being filled -in by the translation and type-check handlers which handle the -request, respectively). <P> - -Other commonly used data items are tables giving the MIME headers on -the client's original request, MIME headers to be sent back with the -response (which modules can add to at will), and environment variables -for any subprocesses which are spawned off in the course of servicing -the request. These tables are manipulated using the -<CODE>ap_table_get</CODE> and <CODE>ap_table_set</CODE> routines. <P> -<BLOCKQUOTE> - Note that the <SAMP>Content-type</SAMP> header value <EM>cannot</EM> be - set by module content-handlers using the <SAMP>ap_table_*()</SAMP> - routines. Rather, it is set by pointing the <SAMP>content_type</SAMP> - field in the <SAMP>request_rec</SAMP> structure to an appropriate - string. <EM>E.g.</EM>, - <PRE> - r->content_type = "text/html"; - </PRE> -</BLOCKQUOTE> -Finally, there are pointers to two data structures which, in turn, -point to per-module configuration structures. Specifically, these -hold pointers to the data structures which the module has built to -describe the way it has been configured to operate in a given -directory (via <CODE>.htaccess</CODE> files or -<CODE><Directory></CODE> sections), for private data it has -built in the course of servicing the request (so modules' handlers for -one phase can pass `notes' to their handlers for other phases). There -is another such configuration vector in the <CODE>server_rec</CODE> -data structure pointed to by the <CODE>request_rec</CODE>, which -contains per (virtual) server configuration data.<P> - -Here is an abridged declaration, giving the fields most commonly used:<P> - -<PRE> -struct request_rec { - - pool *pool; - conn_rec *connection; - server_rec *server; - - /* What object is being requested */ - - char *uri; - char *filename; - char *path_info; - char *args; /* QUERY_ARGS, if any */ - struct stat finfo; /* Set by server core; - * st_mode set to zero if no such file */ - - char *content_type; - char *content_encoding; - - /* MIME header environments, in and out. Also, an array containing - * environment variables to be passed to subprocesses, so people can - * write modules to add to that environment. - * - * The difference between headers_out and err_headers_out is that - * the latter are printed even on error, and persist across internal - * redirects (so the headers printed for ErrorDocument handlers will - * have them). - */ - - table *headers_in; - table *headers_out; - table *err_headers_out; - table *subprocess_env; - - /* Info about the request itself... */ - - int header_only; /* HEAD request, as opposed to GET */ - char *protocol; /* Protocol, as given to us, or HTTP/0.9 */ - char *method; /* GET, HEAD, POST, <EM>etc.</EM> */ - int method_number; /* M_GET, M_POST, <EM>etc.</EM> */ - - /* Info for logging */ - - char *the_request; - int bytes_sent; - - /* A flag which modules can set, to indicate that the data being - * returned is volatile, and clients should be told not to cache it. - */ - - int no_cache; - - /* Various other config info which may change with .htaccess files - * These are config vectors, with one void* pointer for each module - * (the thing pointed to being the module's business). - */ - - void *per_dir_config; /* Options set in config files, <EM>etc.</EM> */ - void *request_config; /* Notes on *this* request */ - -}; - -</PRE> - -<H3><A NAME="req_orig">Where request_rec structures come from</A></H3> - -Most <CODE>request_rec</CODE> structures are built by reading an HTTP -request from a client, and filling in the fields. However, there are -a few exceptions: - -<UL> - <LI> If the request is to an imagemap, a type map (<EM>i.e.</EM>, a - <CODE>*.var</CODE> file), or a CGI script which returned a - local `Location:', then the resource which the user requested - is going to be ultimately located by some URI other than what - the client originally supplied. In this case, the server does - an <EM>internal redirect</EM>, constructing a new - <CODE>request_rec</CODE> for the new URI, and processing it - almost exactly as if the client had requested the new URI - directly. <P> - - <LI> If some handler signaled an error, and an - <CODE>ErrorDocument</CODE> is in scope, the same internal - redirect machinery comes into play.<P> - - <LI> Finally, a handler occasionally needs to investigate `what - would happen if' some other request were run. For instance, - the directory indexing module needs to know what MIME type - would be assigned to a request for each directory entry, in - order to figure out what icon to use.<P> - - Such handlers can construct a <EM>sub-request</EM>, using the - functions <CODE>ap_sub_req_lookup_file</CODE>, - <CODE>ap_sub_req_lookup_uri</CODE>, and - <CODE>ap_sub_req_method_uri</CODE>; these construct a new - <CODE>request_rec</CODE> structure and processes it as you - would expect, up to but not including the point of actually - sending a response. (These functions skip over the access - checks if the sub-request is for a file in the same directory - as the original request).<P> - - (Server-side includes work by building sub-requests and then - actually invoking the response handler for them, via the - function <CODE>ap_run_sub_req</CODE>). -</UL> - -<H3><A NAME="req_return">Handling requests, declining, and returning error - codes</A></H3> - -As discussed above, each handler, when invoked to handle a particular -<CODE>request_rec</CODE>, has to return an <CODE>int</CODE> to -indicate what happened. That can either be - -<UL> - <LI> OK --- the request was handled successfully. This may or may - not terminate the phase. - <LI> DECLINED --- no erroneous condition exists, but the module - declines to handle the phase; the server tries to find another. - <LI> an HTTP error code, which aborts handling of the request. -</UL> - -Note that if the error code returned is <CODE>REDIRECT</CODE>, then -the module should put a <CODE>Location</CODE> in the request's -<CODE>headers_out</CODE>, to indicate where the client should be -redirected <EM>to</EM>. <P> - -<H3><A NAME="resp_handlers">Special considerations for response - handlers</A></H3> - -Handlers for most phases do their work by simply setting a few fields -in the <CODE>request_rec</CODE> structure (or, in the case of access -checkers, simply by returning the correct error code). However, -response handlers have to actually send a request back to the client. <P> - -They should begin by sending an HTTP response header, using the -function <CODE>ap_send_http_header</CODE>. (You don't have to do -anything special to skip sending the header for HTTP/0.9 requests; the -function figures out on its own that it shouldn't do anything). If -the request is marked <CODE>header_only</CODE>, that's all they should -do; they should return after that, without attempting any further -output. <P> - -Otherwise, they should produce a request body which responds to the -client as appropriate. The primitives for this are <CODE>ap_rputc</CODE> -and <CODE>ap_rprintf</CODE>, for internally generated output, and -<CODE>ap_send_fd</CODE>, to copy the contents of some <CODE>FILE *</CODE> -straight to the client. <P> - -At this point, you should more or less understand the following piece -of code, which is the handler which handles <CODE>GET</CODE> requests -which have no more specific handler; it also shows how conditional -<CODE>GET</CODE>s can be handled, if it's desirable to do so in a -particular response handler --- <CODE>ap_set_last_modified</CODE> checks -against the <CODE>If-modified-since</CODE> value supplied by the -client, if any, and returns an appropriate code (which will, if -nonzero, be USE_LOCAL_COPY). No similar considerations apply for -<CODE>ap_set_content_length</CODE>, but it returns an error code for -symmetry.<P> - -<PRE> -int default_handler (request_rec *r) -{ - int errstatus; - FILE *f; - - if (r->method_number != M_GET) return DECLINED; - if (r->finfo.st_mode == 0) return NOT_FOUND; - - if ((errstatus = ap_set_content_length (r, r->finfo.st_size)) - || (errstatus = ap_set_last_modified (r, r->finfo.st_mtime))) - return errstatus; - - f = fopen (r->filename, "r"); - - if (f == NULL) { - log_reason("file permissions deny server access", - r->filename, r); - return FORBIDDEN; - } - - register_timeout ("send", r); - ap_send_http_header (r); - - if (!r->header_only) send_fd (f, r); - ap_pfclose (r->pool, f); - return OK; -} -</PRE> - -Finally, if all of this is too much of a challenge, there are a few -ways out of it. First off, as shown above, a response handler which -has not yet produced any output can simply return an error code, in -which case the server will automatically produce an error response. -Secondly, it can punt to some other handler by invoking -<CODE>ap_internal_redirect</CODE>, which is how the internal redirection -machinery discussed above is invoked. A response handler which has -internally redirected should always return <CODE>OK</CODE>. <P> - -(Invoking <CODE>ap_internal_redirect</CODE> from handlers which are -<EM>not</EM> response handlers will lead to serious confusion). - -<H3><A NAME="auth_handlers">Special considerations for authentication - handlers</A></H3> - -Stuff that should be discussed here in detail: - -<UL> - <LI> Authentication-phase handlers not invoked unless auth is - configured for the directory. - <LI> Common auth configuration stored in the core per-dir - configuration; it has accessors <CODE>ap_auth_type</CODE>, - <CODE>ap_auth_name</CODE>, and <CODE>ap_requires</CODE>. - <LI> Common routines, to handle the protocol end of things, at least - for HTTP basic authentication (<CODE>ap_get_basic_auth_pw</CODE>, - which sets the <CODE>connection->user</CODE> structure field - automatically, and <CODE>ap_note_basic_auth_failure</CODE>, which - arranges for the proper <CODE>WWW-Authenticate:</CODE> header - to be sent back). -</UL> - -<H3><A NAME="log_handlers">Special considerations for logging handlers</A></H3> - -When a request has internally redirected, there is the question of -what to log. Apache handles this by bundling the entire chain of -redirects into a list of <CODE>request_rec</CODE> structures which are -threaded through the <CODE>r->prev</CODE> and <CODE>r->next</CODE> -pointers. The <CODE>request_rec</CODE> which is passed to the logging -handlers in such cases is the one which was originally built for the -initial request from the client; note that the bytes_sent field will -only be correct in the last request in the chain (the one for which a -response was actually sent). - -<H2><A NAME="pools">Resource allocation and resource pools</A></H2> -<P> -One of the problems of writing and designing a server-pool server is -that of preventing leakage, that is, allocating resources (memory, -open files, <EM>etc.</EM>), without subsequently releasing them. The resource -pool machinery is designed to make it easy to prevent this from -happening, by allowing resource to be allocated in such a way that -they are <EM>automatically</EM> released when the server is done with -them. -</P> -<P> -The way this works is as follows: the memory which is allocated, file -opened, <EM>etc.</EM>, to deal with a particular request are tied to a -<EM>resource pool</EM> which is allocated for the request. The pool -is a data structure which itself tracks the resources in question. -</P> -<P> -When the request has been processed, the pool is <EM>cleared</EM>. At -that point, all the memory associated with it is released for reuse, -all files associated with it are closed, and any other clean-up -functions which are associated with the pool are run. When this is -over, we can be confident that all the resource tied to the pool have -been released, and that none of them have leaked. -</P> -<P> -Server restarts, and allocation of memory and resources for per-server -configuration, are handled in a similar way. There is a -<EM>configuration pool</EM>, which keeps track of resources which were -allocated while reading the server configuration files, and handling -the commands therein (for instance, the memory that was allocated for -per-server module configuration, log files and other files that were -opened, and so forth). When the server restarts, and has to reread -the configuration files, the configuration pool is cleared, and so the -memory and file descriptors which were taken up by reading them the -last time are made available for reuse. -</P> -<P> -It should be noted that use of the pool machinery isn't generally -obligatory, except for situations like logging handlers, where you -really need to register cleanups to make sure that the log file gets -closed when the server restarts (this is most easily done by using the -function <CODE><A HREF="#pool-files">ap_pfopen</A></CODE>, which also -arranges for the underlying file descriptor to be closed before any -child processes, such as for CGI scripts, are <CODE>exec</CODE>ed), or -in case you are using the timeout machinery (which isn't yet even -documented here). However, there are two benefits to using it: -resources allocated to a pool never leak (even if you allocate a -scratch string, and just forget about it); also, for memory -allocation, <CODE>ap_palloc</CODE> is generally faster than -<CODE>malloc</CODE>. -</P> -<P> -We begin here by describing how memory is allocated to pools, and then -discuss how other resources are tracked by the resource pool -machinery. -</P> -<H3>Allocation of memory in pools</H3> -<P> -Memory is allocated to pools by calling the function -<CODE>ap_palloc</CODE>, which takes two arguments, one being a pointer to -a resource pool structure, and the other being the amount of memory to -allocate (in <CODE>char</CODE>s). Within handlers for handling -requests, the most common way of getting a resource pool structure is -by looking at the <CODE>pool</CODE> slot of the relevant -<CODE>request_rec</CODE>; hence the repeated appearance of the -following idiom in module code: -</P> -<PRE> -int my_handler(request_rec *r) -{ - struct my_structure *foo; - ... - - foo = (foo *)ap_palloc (r->pool, sizeof(my_structure)); -} -</PRE> -<P> -Note that <EM>there is no <CODE>ap_pfree</CODE></EM> --- -<CODE>ap_palloc</CODE>ed memory is freed only when the associated -resource pool is cleared. This means that <CODE>ap_palloc</CODE> does not -have to do as much accounting as <CODE>malloc()</CODE>; all it does in -the typical case is to round up the size, bump a pointer, and do a -range check. -</P> -<P> -(It also raises the possibility that heavy use of <CODE>ap_palloc</CODE> -could cause a server process to grow excessively large. There are -two ways to deal with this, which are dealt with below; briefly, you -can use <CODE>malloc</CODE>, and try to be sure that all of the memory -gets explicitly <CODE>free</CODE>d, or you can allocate a sub-pool of -the main pool, allocate your memory in the sub-pool, and clear it out -periodically. The latter technique is discussed in the section on -sub-pools below, and is used in the directory-indexing code, in order -to avoid excessive storage allocation when listing directories with -thousands of files). -</P> -<H3>Allocating initialized memory</H3> -<P> -There are functions which allocate initialized memory, and are -frequently useful. The function <CODE>ap_pcalloc</CODE> has the same -interface as <CODE>ap_palloc</CODE>, but clears out the memory it -allocates before it returns it. The function <CODE>ap_pstrdup</CODE> -takes a resource pool and a <CODE>char *</CODE> as arguments, and -allocates memory for a copy of the string the pointer points to, -returning a pointer to the copy. Finally <CODE>ap_pstrcat</CODE> is a -varargs-style function, which takes a pointer to a resource pool, and -at least two <CODE>char *</CODE> arguments, the last of which must be -<CODE>NULL</CODE>. It allocates enough memory to fit copies of each -of the strings, as a unit; for instance: -</P> -<PRE> - ap_pstrcat (r->pool, "foo", "/", "bar", NULL); -</PRE> -<P> -returns a pointer to 8 bytes worth of memory, initialized to -<CODE>"foo/bar"</CODE>. -</P> -<H3><A NAME="pools-used">Commonly-used pools in the Apache Web server</A></H3> -<P> -A pool is really defined by its lifetime more than anything else. There -are some static pools in http_main which are passed to various -non-http_main functions as arguments at opportune times. Here they are: -</P> -<DL COMPACT> - <DT>permanent_pool - </DT> - <DD> - <UL> - <LI>never passed to anything else, this is the ancestor of all pools - </LI> - </UL> - </DD> - <DT>pconf - </DT> - <DD> - <UL> - <LI>subpool of permanent_pool - </LI> - <LI>created at the beginning of a config "cycle"; exists until the - server is terminated or restarts; passed to all config-time - routines, either via cmd->pool, or as the "pool *p" argument on - those which don't take pools - </LI> - <LI>passed to the module init() functions - </LI> - </UL> - </DD> - <DT>ptemp - </DT> - <DD> - <UL> - <LI>sorry I lie, this pool isn't called this currently in 1.3, I - renamed it this in my pthreads development. I'm referring to - the use of ptrans in the parent... contrast this with the later - definition of ptrans in the child. - </LI> - <LI>subpool of permanent_pool - </LI> - <LI>created at the beginning of a config "cycle"; exists until the - end of config parsing; passed to config-time routines <EM>via</EM> - cmd->temp_pool. Somewhat of a "bastard child" because it isn't - available everywhere. Used for temporary scratch space which - may be needed by some config routines but which is deleted at - the end of config. - </LI> - </UL> - </DD> - <DT>pchild - </DT> - <DD> - <UL> - <LI>subpool of permanent_pool - </LI> - <LI>created when a child is spawned (or a thread is created); lives - until that child (thread) is destroyed - </LI> - <LI>passed to the module child_init functions - </LI> - <LI>destruction happens right after the child_exit functions are - called... (which may explain why I think child_exit is redundant - and unneeded) - </LI> - </UL> - </DD> - <DT>ptrans - <DT> - <DD> - <UL> - <LI>should be a subpool of pchild, but currently is a subpool of - permanent_pool, see above - </LI> - <LI>cleared by the child before going into the accept() loop to receive - a connection - </LI> - <LI>used as connection->pool - </LI> - </UL> - </DD> - <DT>r->pool - </DT> - <DD> - <UL> - <LI>for the main request this is a subpool of connection->pool; for - subrequests it is a subpool of the parent request's pool. - </LI> - <LI>exists until the end of the request (<EM>i.e.</EM>, - ap_destroy_sub_req, or - in child_main after process_request has finished) - </LI> - <LI>note that r itself is allocated from r->pool; <EM>i.e.</EM>, - r->pool is - first created and then r is the first thing palloc()d from it - </LI> - </UL> - </DD> -</DL> -<P> -For almost everything folks do, r->pool is the pool to use. But you -can see how other lifetimes, such as pchild, are useful to some -modules... such as modules that need to open a database connection once -per child, and wish to clean it up when the child dies. -</P> -<P> -You can also see how some bugs have manifested themself, such as setting -connection->user to a value from r->pool -- in this case -connection exists -for the lifetime of ptrans, which is longer than r->pool (especially if -r->pool is a subrequest!). So the correct thing to do is to allocate -from connection->pool. -</P> -<P> -And there was another interesting bug in mod_include/mod_cgi. You'll see -in those that they do this test to decide if they should use r->pool -or r->main->pool. In this case the resource that they are registering -for cleanup is a child process. If it were registered in r->pool, -then the code would wait() for the child when the subrequest finishes. -With mod_include this could be any old #include, and the delay can be up -to 3 seconds... and happened quite frequently. Instead the subprocess -is registered in r->main->pool which causes it to be cleaned up when -the entire request is done -- <EM>i.e.</EM>, after the output has been sent to -the client and logging has happened. -</P> -<H3><A NAME="pool-files">Tracking open files, etc.</A></H3> -<P> -As indicated above, resource pools are also used to track other sorts -of resources besides memory. The most common are open files. The -routine which is typically used for this is <CODE>ap_pfopen</CODE>, which -takes a resource pool and two strings as arguments; the strings are -the same as the typical arguments to <CODE>fopen</CODE>, <EM>e.g.</EM>, -</P> -<PRE> - ... - FILE *f = ap_pfopen (r->pool, r->filename, "r"); - - if (f == NULL) { ... } else { ... } -</PRE> -<P> -There is also a <CODE>ap_popenf</CODE> routine, which parallels the -lower-level <CODE>open</CODE> system call. Both of these routines -arrange for the file to be closed when the resource pool in question -is cleared. -</P> -<P> -Unlike the case for memory, there <EM>are</EM> functions to close -files allocated with <CODE>ap_pfopen</CODE>, and <CODE>ap_popenf</CODE>, -namely <CODE>ap_pfclose</CODE> and <CODE>ap_pclosef</CODE>. (This is -because, on many systems, the number of files which a single process -can have open is quite limited). It is important to use these -functions to close files allocated with <CODE>ap_pfopen</CODE> and -<CODE>ap_popenf</CODE>, since to do otherwise could cause fatal errors on -systems such as Linux, which react badly if the same -<CODE>FILE*</CODE> is closed more than once. -</P> -<P> -(Using the <CODE>close</CODE> functions is not mandatory, since the -file will eventually be closed regardless, but you should consider it -in cases where your module is opening, or could open, a lot of files). -</P> -<H3>Other sorts of resources --- cleanup functions</H3> -<BLOCKQUOTE> -More text goes here. Describe the the cleanup primitives in terms of -which the file stuff is implemented; also, <CODE>spawn_process</CODE>. -</BLOCKQUOTE> -<P> -Pool cleanups live until clear_pool() is called: clear_pool(a) recursively -calls destroy_pool() on all subpools of a; then calls all the cleanups for a; -then releases all the memory for a. destroy_pool(a) calls clear_pool(a) -and then releases the pool structure itself. <EM>i.e.</EM>, clear_pool(a) doesn't -delete a, it just frees up all the resources and you can start using it -again immediately. -</P> -<H3>Fine control --- creating and dealing with sub-pools, with a note -on sub-requests</H3> - -On rare occasions, too-free use of <CODE>ap_palloc()</CODE> and the -associated primitives may result in undesirably profligate resource -allocation. You can deal with such a case by creating a -<EM>sub-pool</EM>, allocating within the sub-pool rather than the main -pool, and clearing or destroying the sub-pool, which releases the -resources which were associated with it. (This really <EM>is</EM> a -rare situation; the only case in which it comes up in the standard -module set is in case of listing directories, and then only with -<EM>very</EM> large directories. Unnecessary use of the primitives -discussed here can hair up your code quite a bit, with very little -gain). <P> - -The primitive for creating a sub-pool is <CODE>ap_make_sub_pool</CODE>, -which takes another pool (the parent pool) as an argument. When the -main pool is cleared, the sub-pool will be destroyed. The sub-pool -may also be cleared or destroyed at any time, by calling the functions -<CODE>ap_clear_pool</CODE> and <CODE>ap_destroy_pool</CODE>, respectively. -(The difference is that <CODE>ap_clear_pool</CODE> frees resources -associated with the pool, while <CODE>ap_destroy_pool</CODE> also -deallocates the pool itself. In the former case, you can allocate new -resources within the pool, and clear it again, and so forth; in the -latter case, it is simply gone). <P> - -One final note --- sub-requests have their own resource pools, which -are sub-pools of the resource pool for the main request. The polite -way to reclaim the resources associated with a sub request which you -have allocated (using the <CODE>ap_sub_req_...</CODE> functions) -is <CODE>ap_destroy_sub_req</CODE>, which frees the resource pool. -Before calling this function, be sure to copy anything that you care -about which might be allocated in the sub-request's resource pool into -someplace a little less volatile (for instance, the filename in its -<CODE>request_rec</CODE> structure). <P> - -(Again, under most circumstances, you shouldn't feel obliged to call -this function; only 2K of memory or so are allocated for a typical sub -request, and it will be freed anyway when the main request pool is -cleared. It is only when you are allocating many, many sub-requests -for a single main request that you should seriously consider the -<CODE>ap_destroy_...</CODE> functions). - -<H2><A NAME="config">Configuration, commands and the like</A></H2> - -One of the design goals for this server was to maintain external -compatibility with the NCSA 1.3 server --- that is, to read the same -configuration files, to process all the directives therein correctly, -and in general to be a drop-in replacement for NCSA. On the other -hand, another design goal was to move as much of the server's -functionality into modules which have as little as possible to do with -the monolithic server core. The only way to reconcile these goals is -to move the handling of most commands from the central server into the -modules. <P> - -However, just giving the modules command tables is not enough to -divorce them completely from the server core. The server has to -remember the commands in order to act on them later. That involves -maintaining data which is private to the modules, and which can be -either per-server, or per-directory. Most things are per-directory, -including in particular access control and authorization information, -but also information on how to determine file types from suffixes, -which can be modified by <CODE>AddType</CODE> and -<CODE>DefaultType</CODE> directives, and so forth. In general, the -governing philosophy is that anything which <EM>can</EM> be made -configurable by directory should be; per-server information is -generally used in the standard set of modules for information like -<CODE>Alias</CODE>es and <CODE>Redirect</CODE>s which come into play -before the request is tied to a particular place in the underlying -file system. <P> - -Another requirement for emulating the NCSA server is being able to -handle the per-directory configuration files, generally called -<CODE>.htaccess</CODE> files, though even in the NCSA server they can -contain directives which have nothing at all to do with access -control. Accordingly, after URI -> filename translation, but before -performing any other phase, the server walks down the directory -hierarchy of the underlying filesystem, following the translated -pathname, to read any <CODE>.htaccess</CODE> files which might be -present. The information which is read in then has to be -<EM>merged</EM> with the applicable information from the server's own -config files (either from the <CODE><Directory></CODE> sections -in <CODE>access.conf</CODE>, or from defaults in -<CODE>srm.conf</CODE>, which actually behaves for most purposes almost -exactly like <CODE><Directory /></CODE>).<P> - -Finally, after having served a request which involved reading -<CODE>.htaccess</CODE> files, we need to discard the storage allocated -for handling them. That is solved the same way it is solved wherever -else similar problems come up, by tying those structures to the -per-transaction resource pool. <P> - -<H3><A NAME="per-dir">Per-directory configuration structures</A></H3> - -Let's look out how all of this plays out in <CODE>mod_mime.c</CODE>, -which defines the file typing handler which emulates the NCSA server's -behavior of determining file types from suffixes. What we'll be -looking at, here, is the code which implements the -<CODE>AddType</CODE> and <CODE>AddEncoding</CODE> commands. These -commands can appear in <CODE>.htaccess</CODE> files, so they must be -handled in the module's private per-directory data, which in fact, -consists of two separate <CODE>table</CODE>s for MIME types and -encoding information, and is declared as follows: - -<PRE> -typedef struct { - table *forced_types; /* Additional AddTyped stuff */ - table *encoding_types; /* Added with AddEncoding... */ -} mime_dir_config; -</PRE> - -When the server is reading a configuration file, or -<CODE><Directory></CODE> section, which includes one of the MIME -module's commands, it needs to create a <CODE>mime_dir_config</CODE> -structure, so those commands have something to act on. It does this -by invoking the function it finds in the module's `create per-dir -config slot', with two arguments: the name of the directory to which -this configuration information applies (or <CODE>NULL</CODE> for -<CODE>srm.conf</CODE>), and a pointer to a resource pool in which the -allocation should happen. <P> - -(If we are reading a <CODE>.htaccess</CODE> file, that resource pool -is the per-request resource pool for the request; otherwise it is a -resource pool which is used for configuration data, and cleared on -restarts. Either way, it is important for the structure being created -to vanish when the pool is cleared, by registering a cleanup on the -pool if necessary). <P> - -For the MIME module, the per-dir config creation function just -<CODE>ap_palloc</CODE>s the structure above, and a creates a couple of -<CODE>table</CODE>s to fill it. That looks like this: - -<PRE> -void *create_mime_dir_config (pool *p, char *dummy) -{ - mime_dir_config *new = - (mime_dir_config *) ap_palloc (p, sizeof(mime_dir_config)); - - new->forced_types = ap_make_table (p, 4); - new->encoding_types = ap_make_table (p, 4); - - return new; -} -</PRE> - -Now, suppose we've just read in a <CODE>.htaccess</CODE> file. We -already have the per-directory configuration structure for the next -directory up in the hierarchy. If the <CODE>.htaccess</CODE> file we -just read in didn't have any <CODE>AddType</CODE> or -<CODE>AddEncoding</CODE> commands, its per-directory config structure -for the MIME module is still valid, and we can just use it. -Otherwise, we need to merge the two structures somehow. <P> - -To do that, the server invokes the module's per-directory config merge -function, if one is present. That function takes three arguments: -the two structures being merged, and a resource pool in which to -allocate the result. For the MIME module, all that needs to be done -is overlay the tables from the new per-directory config structure with -those from the parent: - -<PRE> -void *merge_mime_dir_configs (pool *p, void *parent_dirv, void *subdirv) -{ - mime_dir_config *parent_dir = (mime_dir_config *)parent_dirv; - mime_dir_config *subdir = (mime_dir_config *)subdirv; - mime_dir_config *new = - (mime_dir_config *)ap_palloc (p, sizeof(mime_dir_config)); - - new->forced_types = ap_overlay_tables (p, subdir->forced_types, - parent_dir->forced_types); - new->encoding_types = ap_overlay_tables (p, subdir->encoding_types, - parent_dir->encoding_types); - - return new; -} -</PRE> - -As a note --- if there is no per-directory merge function present, the -server will just use the subdirectory's configuration info, and ignore -the parent's. For some modules, that works just fine (<EM>e.g.</EM>, for the -includes module, whose per-directory configuration information -consists solely of the state of the <CODE>XBITHACK</CODE>), and for -those modules, you can just not declare one, and leave the -corresponding structure slot in the module itself <CODE>NULL</CODE>.<P> - -<H3><A NAME="commands">Command handling</A></H3> - -Now that we have these structures, we need to be able to figure out -how to fill them. That involves processing the actual -<CODE>AddType</CODE> and <CODE>AddEncoding</CODE> commands. To find -commands, the server looks in the module's <CODE>command table</CODE>. -That table contains information on how many arguments the commands -take, and in what formats, where it is permitted, and so forth. That -information is sufficient to allow the server to invoke most -command-handling functions with pre-parsed arguments. Without further -ado, let's look at the <CODE>AddType</CODE> command handler, which -looks like this (the <CODE>AddEncoding</CODE> command looks basically -the same, and won't be shown here): - -<PRE> -char *add_type(cmd_parms *cmd, mime_dir_config *m, char *ct, char *ext) -{ - if (*ext == '.') ++ext; - ap_table_set (m->forced_types, ext, ct); - return NULL; -} -</PRE> - -This command handler is unusually simple. As you can see, it takes -four arguments, two of which are pre-parsed arguments, the third being -the per-directory configuration structure for the module in question, -and the fourth being a pointer to a <CODE>cmd_parms</CODE> structure. -That structure contains a bunch of arguments which are frequently of -use to some, but not all, commands, including a resource pool (from -which memory can be allocated, and to which cleanups should be tied), -and the (virtual) server being configured, from which the module's -per-server configuration data can be obtained if required.<P> - -Another way in which this particular command handler is unusually -simple is that there are no error conditions which it can encounter. -If there were, it could return an error message instead of -<CODE>NULL</CODE>; this causes an error to be printed out on the -server's <CODE>stderr</CODE>, followed by a quick exit, if it is in -the main config files; for a <CODE>.htaccess</CODE> file, the syntax -error is logged in the server error log (along with an indication of -where it came from), and the request is bounced with a server error -response (HTTP error status, code 500). <P> - -The MIME module's command table has entries for these commands, which -look like this: - -<PRE> -command_rec mime_cmds[] = { -{ "AddType", add_type, NULL, OR_FILEINFO, TAKE2, - "a mime type followed by a file extension" }, -{ "AddEncoding", add_encoding, NULL, OR_FILEINFO, TAKE2, - "an encoding (<EM>e.g.</EM>, gzip), followed by a file extension" }, -{ NULL } -}; -</PRE> - -The entries in these tables are: - -<UL> - <LI> The name of the command - <LI> The function which handles it - <LI> a <CODE>(void *)</CODE> pointer, which is passed in the - <CODE>cmd_parms</CODE> structure to the command handler --- - this is useful in case many similar commands are handled by the - same function. - <LI> A bit mask indicating where the command may appear. There are - mask bits corresponding to each <CODE>AllowOverride</CODE> - option, and an additional mask bit, <CODE>RSRC_CONF</CODE>, - indicating that the command may appear in the server's own - config files, but <EM>not</EM> in any <CODE>.htaccess</CODE> - file. - <LI> A flag indicating how many arguments the command handler wants - pre-parsed, and how they should be passed in. - <CODE>TAKE2</CODE> indicates two pre-parsed arguments. Other - options are <CODE>TAKE1</CODE>, which indicates one pre-parsed - argument, <CODE>FLAG</CODE>, which indicates that the argument - should be <CODE>On</CODE> or <CODE>Off</CODE>, and is passed in - as a boolean flag, <CODE>RAW_ARGS</CODE>, which causes the - server to give the command the raw, unparsed arguments - (everything but the command name itself). There is also - <CODE>ITERATE</CODE>, which means that the handler looks the - same as <CODE>TAKE1</CODE>, but that if multiple arguments are - present, it should be called multiple times, and finally - <CODE>ITERATE2</CODE>, which indicates that the command handler - looks like a <CODE>TAKE2</CODE>, but if more arguments are - present, then it should be called multiple times, holding the - first argument constant. - <LI> Finally, we have a string which describes the arguments that - should be present. If the arguments in the actual config file - are not as required, this string will be used to help give a - more specific error message. (You can safely leave this - <CODE>NULL</CODE>). -</UL> - -Finally, having set this all up, we have to use it. This is -ultimately done in the module's handlers, specifically for its -file-typing handler, which looks more or less like this; note that the -per-directory configuration structure is extracted from the -<CODE>request_rec</CODE>'s per-directory configuration vector by using -the <CODE>ap_get_module_config</CODE> function. - -<PRE> -int find_ct(request_rec *r) -{ - int i; - char *fn = ap_pstrdup (r->pool, r->filename); - mime_dir_config *conf = (mime_dir_config *) - ap_get_module_config(r->per_dir_config, &mime_module); - char *type; - - if (S_ISDIR(r->finfo.st_mode)) { - r->content_type = DIR_MAGIC_TYPE; - return OK; - } - - if((i=ap_rind(fn,'.')) < 0) return DECLINED; - ++i; - - if ((type = ap_table_get (conf->encoding_types, &fn[i]))) - { - r->content_encoding = type; - - /* go back to previous extension to try to use it as a type */ - - fn[i-1] = '\0'; - if((i=ap_rind(fn,'.')) < 0) return OK; - ++i; - } - - if ((type = ap_table_get (conf->forced_types, &fn[i]))) - { - r->content_type = type; - } - - return OK; -} - -</PRE> - -<H3><A NAME="servconf">Side notes --- per-server configuration, virtual - servers, <EM>etc</EM>.</A></H3> - -The basic ideas behind per-server module configuration are basically -the same as those for per-directory configuration; there is a creation -function and a merge function, the latter being invoked where a -virtual server has partially overridden the base server configuration, -and a combined structure must be computed. (As with per-directory -configuration, the default if no merge function is specified, and a -module is configured in some virtual server, is that the base -configuration is simply ignored). <P> - -The only substantial difference is that when a command needs to -configure the per-server private module data, it needs to go to the -<CODE>cmd_parms</CODE> data to get at it. Here's an example, from the -alias module, which also indicates how a syntax error can be returned -(note that the per-directory configuration argument to the command -handler is declared as a dummy, since the module doesn't actually have -per-directory config data): - -<PRE> -char *add_redirect(cmd_parms *cmd, void *dummy, char *f, char *url) -{ - server_rec *s = cmd->server; - alias_server_conf *conf = (alias_server_conf *) - ap_get_module_config(s->module_config,&alias_module); - alias_entry *new = ap_push_array (conf->redirects); - - if (!ap_is_url (url)) return "Redirect to non-URL"; - - new->fake = f; new->real = url; - return NULL; -} -</PRE> -<!--#include virtual="footer.html" --> -</BODY></HTML> diff --git a/docs/manual/developer/debugging.html b/docs/manual/developer/debugging.html deleted file mode 100644 index 581f1b8c58..0000000000 --- a/docs/manual/developer/debugging.html +++ /dev/null @@ -1,178 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<HTML> -<HEAD> -<TITLE>Debugging Memory Allocation in APR</TITLE> -</HEAD> - -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<!--#include virtual="header.html" --> - -<H1 ALIGN="CENTER">Debugging Memory Allocation in APR<br></H1> - -<p>The allocation mechanism's within APR have a number of debugging -modes that can be used to assist in finding memory problems. This document describes -the modes available and gives instructions on activating them.</p> - -<ul> -<li><a href="#options">Available debugging options</a></li> -<li><a href="#combo">Allowable combinations</a></li> -<li><a href="#howto">How to activate debugging</a></li> -</ul> - -<hr> -<a name="options"> -<h2>Allocation Debugging</h2> - -<h3>ALLOC_DEBUG</h3> -<p><em>Debugging support: Define this to enable code which helps detect re-use of freed memory and other such nonsense.</em></p> - -<p>The theory is simple. The FILL_BYTE (0xa5) is written over all malloc'd memory as we receive it, and is written over everything that we free up during a clear_pool. We check that blocks on the free list always have the FILL_BYTE in them, and we check during palloc() that the bytes still have FILL_BYTE in them. If you ever see garbage URLs or whatnot containing lots of 0xa5s then you know something used data that's been freed or uninitialized.</p> - -<h2>Malloc Support</h2> -<h3>ALLOC_USE_MALLOC</h3> -<p><em>If defined all allocations will be done with malloc and free()d appropriately at the end. -</em></p> - -<p>This is intended to be used with something like Electric Fence or Purify to help detect memory problems. Note that if you're using efence then you should also add in ALLOC_DEBUG. But don't add in ALLOC_DEBUG if you're using Purify because ALLOC_DEBUG would hide all the uninitialized read errors that Purify can diagnose.</p> - -<h2>Pool Debugging</h2> -<h3>POOL_DEBUG</h3> -<p><em>This is intended to detect cases where the wrong pool is used when assigning data to an object in another pool.</em></p> - -<p>In particular, it causes the table_{set,add,merge}n routines to check that their arguments are safe for the ap_table_t they're being placed in. It currently only works with the unix multiprocess model, but could be extended to others.</p> - -<h2>Table Debugging</h2> -<h3>MAKE_TABLE_PROFILE</h3> -<p><em>Provide diagnostic information about make_table() calls which are possibly too small.</em></p> - -<p>This requires a recent gcc which supports __builtin_return_address(). The error_log output will be a message such as: </p> -<pre>table_push: ap_table_t created by 0x804d874 hit limit of 10</pre> -<p>Use "<em><strong>l *0x804d874</strong></em>" to find the source that corresponds to. It - indicates that a ap_table_t allocated by a call at that address has possibly too small an initial ap_table_t size guess.</p> - -<h2>Allocation Statistics</h2> -<h3>ALLOC_STATS</h3> -<p><em>Provide some statistics on the cost of allocations.</em></p> - -<p>This requires a bit of an understanding of how alloc.c works.</p> - -<hr> - -<a name="combo"> -<h2>Allowable Combinations</h2> - -<p>Not all the options outlined above can be activated at the same time. the following table gives more information.</p> - -<p align="center"> -<table width="80%"> -<tr> -<th width="25%">Option 1</th> -<th width="15%">ALLOC<br>DEBUG</th> -<th width="15%">ALLOC<br>USE<br>MALLOC</th> -<th width="15%">POOL<br>DEBUG</th> -<th width="15%">MAKE<br>TABLE<br>PROFILE</th> -<th width="15%">ALLOC<br>STATS</th> -</tr> -<tr> -<td>ALLOC_DEBUG</td> -<td bgcolor="#ff0000"> </td> -<td align="center">No</td> -<td align="center">Yes</td> -<td align="center">Yes</td> -<td align="center">Yes</td> -</tr> -<tr> -<td>ALLOC_USE<br>MALLOC</td> -<td align="center">No</td> -<td bgcolor="#ff0000"> </td> -<td align="center">No</td> -<td align="center">No</td> -<td align="center">No</td> -</tr> -<tr> -<td>POOL_DEBUG</td> -<td align="center">Yes</td> -<td align="center">No</td> -<td bgcolor="#ff0000"> </td> -<td align="center">Yes</td> -<td align="center">Yes</td> -</tr> -<tr> -<td>MAKE_TABLE<br>PROFILE</td> -<td align="center">Yes</td> -<td align="center">No</td> -<td align="center">Yes</td> -<td bgcolor="#ff0000"> </td> -<td align="center">Yes</td> -</tr> -<tr> -<td>ALLOC_STATS</td> -<td align="center">Yes</td> -<td align="center">No</td> -<td align="center">Yes</td> -<td align="center">Yes</td> -<td bgcolor="#ff0000"> </td> -</tr> - -</table> - -<p>Additionally the debugging options are not suitable for multi-threaded versions of the server. When trying to debug with these options the server should be started in single process mode.</p> - -<hr> - -<a name="howto"> -<h2>Activating Debugging Options</h2> -<p>The various options for debugging memory are now enabled in the apr_general.h header file in APR. The various options are enabled by uncommenting the define for the option you wish to use. The section of the code currently looks like this <em>(contained in src/lib/apr/inclide/apr_general.h)</em></p> - -<pre> -/* -#define ALLOC_DEBUG -#define POOL_DEBUG -#define ALLOC_USE_MALLOC -#define MAKE_TABLE_PROFILE -#define ALLOC_STATS -*/ - -typedef struct ap_pool_t { - union block_hdr *first; - union block_hdr *last; - struct cleanup *cleanups; - struct process_chain *subprocesses; - struct ap_pool_t *sub_pools; - struct ap_pool_t *sub_next; - struct ap_pool_t *sub_prev; - struct ap_pool_t *parent; - char *free_first_avail; -#ifdef ALLOC_USE_MALLOC - void *allocation_list; -#endif -#ifdef POOL_DEBUG - struct ap_pool_t *joined; -#endif - int (*apr_abort)(int retcode); - struct datastruct *prog_data; -}ap_pool_t; -</pre> - -<p>To enable allocation debugging simply move the #define ALLOC_DEBUG above the start of the comments block and rebuild the server.</p> - -<h3>NB. In order to use the various options the server MUST be rebuilt after editing the header file. -</h3> - -<!--#include virtual="footer.html" --> - -</body> -</html> - - - - - diff --git a/docs/manual/developer/documenting b/docs/manual/developer/documenting deleted file mode 100644 index 0994b10d78..0000000000 --- a/docs/manual/developer/documenting +++ /dev/null @@ -1,43 +0,0 @@ -Apache 2.0 is using ScanDoc to document the API's and global variables in -the code. This will explain the basics of how to document using Scandoc. - -To start a scandoc block, use /** -To end a scandoc block, use */ - -In the middle of the block, there are multiple tags we can use: - - Description of this functions purpose - @param parameter_name description - @tip Any information the programmer should know - @deffunc function prototype. - -The deffunc is not always necessary. ScanDoc does not have a full parser in -it, so any prototype that use a macro in the return type declaration is too -complex for scandoc. Those functions require a deffunc. - -An example: - -/** - * return the final element of the pathname - * @param pathname The path to get the final element of - * @return the final element of the path - * @tip Examples: - * <PRE> - * "/foo/bar/gum" -> "gum" - * "/foo/bar/gum/" -> "" - * "gum" -> "gum" - * "wi\\n32\\stuff" -> "stuff" - * </PRE> - * @deffunc const char * ap_filename_of_pathname(const char *pathname) - */ - -At the top of the header file, we always include - -/** - * @package Name of library header - */ - -ScanDoc uses a new html file for each package. The html files are named: - -Name of library header.html, so try to be concise with your names - diff --git a/docs/manual/developer/footer.html b/docs/manual/developer/footer.html deleted file mode 100644 index 1e5f739ebe..0000000000 --- a/docs/manual/developer/footer.html +++ /dev/null @@ -1,8 +0,0 @@ -<HR> - -<H3 ALIGN="CENTER"> - Apache HTTP Server Version 2.0 -</H3> - -<A HREF="./"><IMG SRC="../images/index.gif" ALT="Index"></A> -<A HREF="../"><IMG SRC="../images/home.gif" ALT="Home"></A> diff --git a/docs/manual/developer/header.html b/docs/manual/developer/header.html deleted file mode 100644 index 9533b02bda..0000000000 --- a/docs/manual/developer/header.html +++ /dev/null @@ -1,6 +0,0 @@ -<DIV ALIGN="CENTER"> - <IMG SRC="../images/sub.gif" ALT="[APACHE DOCUMENTATION]"> - <H3> - Apache HTTP Server Version 2.0 - </H3> -</DIV> diff --git a/docs/manual/developer/hooks.html b/docs/manual/developer/hooks.html deleted file mode 100644 index 6ab1ad6b74..0000000000 --- a/docs/manual/developer/hooks.html +++ /dev/null @@ -1,207 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<html> -<head> -<title>Apache 2.0 Hook Functions</title> -</head> - -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<!--#include virtual="header.html" --> - -<H1 align="center">Apache Hook Functions</H1> - -<P>In general, a hook function is one that Apache will call at some -point during the processing of a request. Modules can provide -functions that are called, and specify when they get called in -comparison to other modules.</P> - -<H2>Creating a hook function</H2> - -<P>In order to create a new hook, four things need to be done:</P> - -<H3>Declare the hook function</H3> - -<P>Use the DECLARE_HOOK macro, which needs to be given the name of the -hook, the return type of the hook function and the arguments. For -example, if the hook returns an <TT>int</TT> and takes a -<TT>request_rec *</TT> and an <TT>int</TT> and is called -"do_something", then declare it like this:</P> - -<TT>DECLARE_HOOK(int,do_something,(request_rec *r,int n))</TT> - -<P>This should go in a header which modules will include if they want -to use the hook.</P> - -<H3>Create the hook structure</H3> - -<P>Each source file that exports a hook has a private structure which -is used to record the module functions that use the hook. This is -declared as follows:</P> - -<PRE> -HOOK_STRUCT( - HOOK_LINK(do_something) - ... - ) -</PRE> - -<H3>Implement the hook caller</H3> - -<P>The source file that exports the hook has to implement a function -that will call the hook. There are currently three possible ways to do -this. In all cases, the calling function is called -<TT>ap_run_<I>hookname</I>()</TT>.</P> - -<H4>Void hooks</H4> - -<P>If the return value of a hook is <TT>void</TT>, then all the hooks are -called, and the caller is implemented like this:</P> - -<TT>IMPLEMENT_HOOK_VOID(do_something,(request_rec *r,int -n),(r,n))</TT> - -<P>The second and third arguments are the dummy argument declaration and -the dummy arguments as they will be used when calling the hook. In -other words, this macro expands to something like this:</P> - -<PRE> -void ap_run_do_something(request_rec *r,int n) -{ - ... - do_something(r,n); -} -</PRE> - -<H4>Hooks that return a value</H4> - -<P>If the hook returns a value, then it can either be run until the first -hook that does something interesting, like so:</P> - -<TT>IMPLEMENT_HOOK_RUN_FIRST(int,do_something,(request_rec *r,int n),(r,n),DECLINED)</TT> - -<P>The first hook that <I>doesn't</I> return <TT>DECLINED</TT> stops -the loop and its return value is returned from the hook caller. Note -that <TT>DECLINED</TT> is the tradition Apache hook return meaning "I -didn't do anything", but it can be whatever suits you.</P> - -<P>Alternatively, all hooks can be run until an error occurs. This -boils down to permitting <I>two</I> return values, one of which means -"I did something, and it was OK" and the other meaning "I did -nothing". The first function that returns a value other than one of -those two stops the loop, and its return is the return value. Declare -these like so:</P> - -<TT>IMPLEMENT_HOOK_RUN_ALL(int,do_something,(request_rec *r,int -n),(r,n),OK,DECLINED)</TT> - -<P>Again, <TT>OK</TT> and <TT>DECLINED</TT> are the traditional -values. You can use what you want.</P> - -<H3>Call the hook callers</H3> - -<P>At appropriate moments in the code, call the hook caller, like -so:</P> - -<PRE> - int n,ret; - request_rec *r; - - ret=ap_run_do_something(r,n); -</PRE> - -<H2>Hooking the hook</H2> - -<P>A module that wants a hook to be called needs to do two -things.</P> - -<H3>Implement the hook function</H3> - -<P>Include the appropriate header, and define a static function of the -correct type:</P> - -<PRE> -static int my_something_doer(request_rec *r,int n) -{ - ... - return OK; -} -</PRE> - -<H3>Add a hook registering function</H3> - -<P>During initialisation, Apache will call each modules hook -registering function, which is included in the module structure:</P> - -<PRE> -static void my_register_hooks() -{ - ap_hook_do_something(my_something_doer,NULL,NULL,HOOK_MIDDLE); -} - -mode MODULE_VAR_EXPORT my_module = -{ - ... - my_register_hooks /* register hooks */ -}; -</PRE> - -<H3>Controlling hook calling order</H3> - -<P>In the example above, we didn't use the three arguments in the hook -registration function that control calling order. There are two -mechanisms for doing this. The first, rather crude, method, allows us -to specify roughly where the hook is run relative to other -modules. The final argument control this. There are three possible -values:</P> - -<PRE> -HOOK_FIRST -HOOK_MIDDLE -HOOK_LAST -</PRE> - -<P>All modules using any particular value may be run in any order -relative to each other, but, of course, all modules using -<TT>HOOK_FIRST</TT> will be run before <TT>HOOK_MIDDLE</TT> which are -before <TT>HOOK_LAST</TT>. Modules that don't care when they are run -should use <TT>HOOK_MIDDLE</TT>. <I>(I spaced these out so people -could do stuff like <TT>HOOK_FIRST-2</TT> to get in slightly earlier, -but is this wise? - Ben)</I></P> - -<P>Note that there are two more values, <TT>HOOK_REALLY_FIRST</TT> and -<TT>HOOK_REALLY_LAST</TT>. These should only be used by the hook -exporter.</P> - -<P>The other method allows finer control. When a module knows that it -must be run before (or after) some other modules, it can specify them -by name. The second (third) argument is a NULL-terminated array of -strings consisting of the names of modules that must be run before -(after) the current module. For example, suppose we want "mod_xyz.c" -and "mod_abc.c" to run before we do, then we'd hook as follows:</P> - -<PRE> -static void register_hooks() -{ - static const char * const aszPre[]={ "mod_xyz.c", "mod_abc.c", NULL }; - - ap_hook_do_something(my_something_doer,aszPre,NULL,HOOK_MIDDLE); -} -</PRE> - -<P>Note that the sort used to achieve this is stable, so ordering set -by <TT>HOOK_<I>ORDER</I></TT> is preserved, as far as is -possible.</P> - -<I>Ben Laurie, 15th August 1999</I> - -<!--#include virtual="footer.html" --> - -</body> -</html> diff --git a/docs/manual/developer/index.html b/docs/manual/developer/index.html deleted file mode 100644 index 93eb0d9d2f..0000000000 --- a/docs/manual/developer/index.html +++ /dev/null @@ -1,25 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<html> -<head> -<title>Apache-2.0 Developer Documentation</title> -</head> -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<!--#include virtual="header.html" --> - -<h1 align="center">Developer Documentation for Apache-2.0</h1> - -<p><a href="hooks.html">Apache Hook Functions</a></p> -<p><a href="modules.html">Converting Apache 1.3 Modules to Apache 2.0</a></p> -<p><a href="debugging.html">Debugging Memory Allocation in APR</a></p> -<p><a href="../misc/API.html">Apache 1.3 API Notes</a></p> -<!--#include virtual="footer.html" --> -</body> -</html> diff --git a/docs/manual/developer/layeredio.html b/docs/manual/developer/layeredio.html deleted file mode 100644 index acf9c1b802..0000000000 --- a/docs/manual/developer/layeredio.html +++ /dev/null @@ -1,76 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<html> -<head> -<title>Apache 2.0 Layered I/O</title> -</head> - -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<H1 align="center">Apache Layered I/O</H1> - -<P>Layered I/O has been the holy grail of Apache module writers for years. -With Apache 2.0, module writers can finally take advantage of layered I/O -in their modules. - -<P>In all previous versions of Apache, only one handler was allowed to modify -the data stream that was sent to the client. With Apache 2.0, one module -can modify the data and then specify that other modules can modify the data -if they would like. - -<H2>Taking advantage of layered I/O</H2> - -<P>In order to make a module use layered I/O, there are some modifications -needed. A new return value has been added for modules, RERUN_HANDLERS. -When a handler returns this value, the core searches through the list of -handlers looking for another module that wants to try the request. - -<P>When a module returns RERUN_HANDLERS, it must modify two fields of the -request_rec, the handler and content_type fields. Most modules will -set the handler field to NULL, and allow the core to choose the which -module gets run next. If these two fields are not modified, then the server -will loop forever calling the same module's handler. - -<P>Most modules should not write out to the network if they want to take -advantage of layered I/O. Two BUFF structures have been added to the -request_rec, one for input and one for output. The module should read and -write to these BUFFs. The module will also have to setup the input field for -the next module in the list. A new function has been added, ap_setup_input, -which all modules should call before they do any reading to get data to modify. -This function checks to determine if the previous module set the input field, -if so, that input is used, if not the file is opened and that data source -is used. The output field is used basically the same way. The module must -set this field before they call ap_r* in order to take advantage of -layered I/O. If this field is not set, ap_r* will write directly to the -client. Usually at the end of a handler, the input (for the next module) -will be the read side of a pipe, and the output will be the write side of -the same pipe. - -<H3>An Example of Layered I/O.</H3> - -<P>This example is the most basic layered I/O example possible. It is -basically CGIs generated by mod_cgi and sent to the network via http_core. - -<P>mod_cgi executes the cgi script, and then sets request_rec->input to -the output pipe of the CGI. It then NULLs out request_rec->handler, and -sets request_rec->content_type to whatever the CGI writes out (in this case, -text/html). Finally, mod_cgi returns RERUN_HANDLERS. - -<P>ap_invoke_handlers() then loops back to the top of the handler list -and searches for a handler that can deal with this content_type. In this case -the correct module is the default_handler from http_core. - -<P>When default handler starts, it calls ap_setup_input, which has found -a valid request_rec->input, so that is used for all inputs. The output field -in the request_rec is NULL, so when default_handler calls an output primitive -it gets sent out over the network.</P> - -<I>Ryan Bloom, 25th March 2000</I> -</body> -</html> diff --git a/docs/manual/developer/modules.html b/docs/manual/developer/modules.html deleted file mode 100644 index 8a265f5ec1..0000000000 --- a/docs/manual/developer/modules.html +++ /dev/null @@ -1,203 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<HTML> -<HEAD> -<TITLE>Converting Modules from Apache 1.3 to Apache 2.0</TITLE> -</HEAD> - -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<!--#include virtual="header.html" --> - -<H1 ALIGN="CENTER">From Apache 1.3 to Apache 2.0<br>Modules</H1> - -<p> -This is a first attempt at writing the lessons I learned when trying to convert the mod_mmap_static module to Apache 2.0. It's by no means definitive and probably won't even be correct in some ways, but it's a start. -</p> -<hr> -<h2>The easier changes... -</h2> - -<h3>Cleanup Routines</h3> -<p> -These now need to be of type ap_status_t and return a value of that type. Normally the return value will be APR_SUCCESS unless there is some need to signal an error in the cleanup. Be aware that even though you signal an error not all code yet checks and acts upon the error. -</p> - -<h3>Initialisation Routines</h3> - -<p> -These should now be renamed to better signify where they sit in the overall process. So the name gets a small change from mmap_init to mmap_post_config. The arguments passed have undergone a radical change and now look like -</p> -<ul style="list-style:none"> -<li>ap_context_t *p,</li> -<li>ap_context_t *plog,</li> -<li>ap_context_t *ptemp,</li> -<li>server_rec *s</li> -</ul> -<p> -Throughout Apache the old pools have been replced by the ap_context_t, though their use remains remarkably similar. -</p> - -<h3>Data Types</h3> -<p> -A lot of the data types have been moved into the APR. This means that some have had a name change, such as the one shown above. The following is a brief list of some of the changes that you are likely to have to make. -<ul style="list-style:none"> -<li>pool becomes ap_context_t</li> -<li>table becomes ap_table_t</li> -</ul> -<hr> - -<h2> -The <em>messier</em> changes... -</h2> -<h3>Register Hooks</h3> -<p> -The new architecture uses a series of hooks to provide for calling your functions. These you'll need to add to your module by way of a new function, static void register_hooks(void). The function is really reasonably straightforward once you understand what needs to be done. Each function that needs calling at some stage in the processing of a request needs to be registered, handlers do not. There are a number of phases where functions can be added, and for each you can specify with a high degree of control the relative order that the function will be called in. -</p> -<p> -This is the code that was added to mod_mmap_static -</p> -<pre> -static void register_hooks(void) -{ - static const char * const aszPre[]={ "http_core.c",NULL }; - ap_hook_post_config(mmap_post_config,NULL,NULL,HOOK_MIDDLE); - ap_hook_translate_name(mmap_static_xlat,aszPre,NULL,HOOK_LAST); -}; -</pre> -<p> -This registers 2 functions that need to be called, one in the post_config stage (virtually every module will need this one) and one for the translate_name phase. note that while there are different function names the format of each is identical. So what is the format? -</p> -<p><strong> -ap_hook_[phase_name](function_name, predecessors, successors, position); -</strong></p> -<p> -There are 3 hook positions defined... -</p> -<ul style="list-style:none"> -<li>HOOK_FIRST</li> -<li>HOOK_MIDDLE</li> -<li>HOOK_LAST</li> -</ul> -<p> -To define the position you use the position and then modify it with the predecessors and successors. each of the modifiers can be a list of functions that should be called, either before the function is run (predecessors) or after the function has run (successors). -</p> -<p> -In the mod_mmap_static case I didn't care about the post_config stage, but the mmap_static_xlat MUST be called after the core module had done it's name translation, hence the use of the aszPre to define a modifier to the position HOOK_LAST. -</p> -<h3>Module Definition</h3> - -<p> -There are now a lot fewer stages to worry about when creating your module definition. The old defintion looked like -</p> -<pre> -module MODULE_VAR_EXPORT [module_name]_module = -{ - STANDARD_MODULE_STUFF, - /* initializer */ - /* dir config creater */ - /* dir merger --- default is to override */ - /* server config */ - /* merge server config */ - /* command handlers */ - /* handlers */ - /* filename translation */ - /* check_user_id */ - /* check auth */ - /* check access */ - /* type_checker */ - /* fixups */ - /* logger */ - /* header parser */ - /* child_init */ - /* child_exit */ - /* post read-request */ -}; -</pre> -<p> -The new structure is a great deal simpler... -</p> -<pre> -module MODULE_VAR_EXPORT [module_name]_module = -{ - STANDARD20_MODULE_STUFF, - /* create per-directory config structures */ - /* merge per-directory config structures */ - /* create per-server config structures */ - /* merge per-server config structures */ - /* command handlers */ - /* handlers */ - /* register hooks */ - }; -</pre> -<p> -Some of these read directly across, some don't. I'll try to summarise what should be done below. -</p> -<p> -The stages that read directly across : -</p> -<ul style="list-style:none"> -<li> -/* dir config creater */ ==> /* create per-directory config structures */ -</li> -<li> -/* server config */ ==> /* create per-server config structures */ -</li> -<li> -/* dir merger */ ==> /* merge per-directory config structures */ -</li> -<li> -/* merge server config */ ==> /* merge per-server config structures */ -</li> -<li> -/* command table */ ==> /* command ap_table_t */ -</li> -<li> -/* handlers */ ==> /* handlers */ -</li> -</ul> -<P> -The remainder of the old functions should be registered as hooks. There are the following hook stages defined so far... -</P> - -<ul style="list-style:none"> -<li> -ap_hook_post_config <em>(this is where the old _init routines get registered)</em> -</li> -<li> -ap_hook_http_method -</li> -<li> -ap_hook_open_logs -</li> -<li> -ap_hook_auth_checker -</li> -<li> -ap_hook_default_port -</li> -<li> -ap_hook_access_checker -</li> -<li> -ap_hook_process_connection -</li> -<li> -ap_hook_child_init_hook -</li> - -<!--#include virtual="footer.html" --> - -</body> -</html> - - - - - diff --git a/docs/manual/developer/modules.html.en b/docs/manual/developer/modules.html.en deleted file mode 100644 index 8a265f5ec1..0000000000 --- a/docs/manual/developer/modules.html.en +++ /dev/null @@ -1,203 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> -<HTML> -<HEAD> -<TITLE>Converting Modules from Apache 1.3 to Apache 2.0</TITLE> -</HEAD> - -<!-- Background white, links blue (unvisited), navy (visited), red (active) --> -<BODY - BGCOLOR="#FFFFFF" - TEXT="#000000" - LINK="#0000FF" - VLINK="#000080" - ALINK="#FF0000" -> - -<!--#include virtual="header.html" --> - -<H1 ALIGN="CENTER">From Apache 1.3 to Apache 2.0<br>Modules</H1> - -<p> -This is a first attempt at writing the lessons I learned when trying to convert the mod_mmap_static module to Apache 2.0. It's by no means definitive and probably won't even be correct in some ways, but it's a start. -</p> -<hr> -<h2>The easier changes... -</h2> - -<h3>Cleanup Routines</h3> -<p> -These now need to be of type ap_status_t and return a value of that type. Normally the return value will be APR_SUCCESS unless there is some need to signal an error in the cleanup. Be aware that even though you signal an error not all code yet checks and acts upon the error. -</p> - -<h3>Initialisation Routines</h3> - -<p> -These should now be renamed to better signify where they sit in the overall process. So the name gets a small change from mmap_init to mmap_post_config. The arguments passed have undergone a radical change and now look like -</p> -<ul style="list-style:none"> -<li>ap_context_t *p,</li> -<li>ap_context_t *plog,</li> -<li>ap_context_t *ptemp,</li> -<li>server_rec *s</li> -</ul> -<p> -Throughout Apache the old pools have been replced by the ap_context_t, though their use remains remarkably similar. -</p> - -<h3>Data Types</h3> -<p> -A lot of the data types have been moved into the APR. This means that some have had a name change, such as the one shown above. The following is a brief list of some of the changes that you are likely to have to make. -<ul style="list-style:none"> -<li>pool becomes ap_context_t</li> -<li>table becomes ap_table_t</li> -</ul> -<hr> - -<h2> -The <em>messier</em> changes... -</h2> -<h3>Register Hooks</h3> -<p> -The new architecture uses a series of hooks to provide for calling your functions. These you'll need to add to your module by way of a new function, static void register_hooks(void). The function is really reasonably straightforward once you understand what needs to be done. Each function that needs calling at some stage in the processing of a request needs to be registered, handlers do not. There are a number of phases where functions can be added, and for each you can specify with a high degree of control the relative order that the function will be called in. -</p> -<p> -This is the code that was added to mod_mmap_static -</p> -<pre> -static void register_hooks(void) -{ - static const char * const aszPre[]={ "http_core.c",NULL }; - ap_hook_post_config(mmap_post_config,NULL,NULL,HOOK_MIDDLE); - ap_hook_translate_name(mmap_static_xlat,aszPre,NULL,HOOK_LAST); -}; -</pre> -<p> -This registers 2 functions that need to be called, one in the post_config stage (virtually every module will need this one) and one for the translate_name phase. note that while there are different function names the format of each is identical. So what is the format? -</p> -<p><strong> -ap_hook_[phase_name](function_name, predecessors, successors, position); -</strong></p> -<p> -There are 3 hook positions defined... -</p> -<ul style="list-style:none"> -<li>HOOK_FIRST</li> -<li>HOOK_MIDDLE</li> -<li>HOOK_LAST</li> -</ul> -<p> -To define the position you use the position and then modify it with the predecessors and successors. each of the modifiers can be a list of functions that should be called, either before the function is run (predecessors) or after the function has run (successors). -</p> -<p> -In the mod_mmap_static case I didn't care about the post_config stage, but the mmap_static_xlat MUST be called after the core module had done it's name translation, hence the use of the aszPre to define a modifier to the position HOOK_LAST. -</p> -<h3>Module Definition</h3> - -<p> -There are now a lot fewer stages to worry about when creating your module definition. The old defintion looked like -</p> -<pre> -module MODULE_VAR_EXPORT [module_name]_module = -{ - STANDARD_MODULE_STUFF, - /* initializer */ - /* dir config creater */ - /* dir merger --- default is to override */ - /* server config */ - /* merge server config */ - /* command handlers */ - /* handlers */ - /* filename translation */ - /* check_user_id */ - /* check auth */ - /* check access */ - /* type_checker */ - /* fixups */ - /* logger */ - /* header parser */ - /* child_init */ - /* child_exit */ - /* post read-request */ -}; -</pre> -<p> -The new structure is a great deal simpler... -</p> -<pre> -module MODULE_VAR_EXPORT [module_name]_module = -{ - STANDARD20_MODULE_STUFF, - /* create per-directory config structures */ - /* merge per-directory config structures */ - /* create per-server config structures */ - /* merge per-server config structures */ - /* command handlers */ - /* handlers */ - /* register hooks */ - }; -</pre> -<p> -Some of these read directly across, some don't. I'll try to summarise what should be done below. -</p> -<p> -The stages that read directly across : -</p> -<ul style="list-style:none"> -<li> -/* dir config creater */ ==> /* create per-directory config structures */ -</li> -<li> -/* server config */ ==> /* create per-server config structures */ -</li> -<li> -/* dir merger */ ==> /* merge per-directory config structures */ -</li> -<li> -/* merge server config */ ==> /* merge per-server config structures */ -</li> -<li> -/* command table */ ==> /* command ap_table_t */ -</li> -<li> -/* handlers */ ==> /* handlers */ -</li> -</ul> -<P> -The remainder of the old functions should be registered as hooks. There are the following hook stages defined so far... -</P> - -<ul style="list-style:none"> -<li> -ap_hook_post_config <em>(this is where the old _init routines get registered)</em> -</li> -<li> -ap_hook_http_method -</li> -<li> -ap_hook_open_logs -</li> -<li> -ap_hook_auth_checker -</li> -<li> -ap_hook_default_port -</li> -<li> -ap_hook_access_checker -</li> -<li> -ap_hook_process_connection -</li> -<li> -ap_hook_child_init_hook -</li> - -<!--#include virtual="footer.html" --> - -</body> -</html> - - - - - |