From fe39ffb8b90ae4e002ed73fe98617cd590abb467 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 08:33:50 +0200 Subject: Adding upstream version 2.4.56. Signed-off-by: Daniel Baumann --- docs/manual/developer/new_api_2_4.html.en | 601 ++++++++++++++++++++++++++++++ 1 file changed, 601 insertions(+) create mode 100644 docs/manual/developer/new_api_2_4.html.en (limited to 'docs/manual/developer/new_api_2_4.html.en') diff --git a/docs/manual/developer/new_api_2_4.html.en b/docs/manual/developer/new_api_2_4.html.en new file mode 100644 index 0000000..6354e85 --- /dev/null +++ b/docs/manual/developer/new_api_2_4.html.en @@ -0,0 +1,601 @@ + + + + + +API Changes in Apache HTTP Server 2.4 since 2.2 - Apache HTTP Server Version 2.4 + + + + + + +
+

Modules | Directives | FAQ | Glossary | Sitemap

+

Apache HTTP Server Version 2.4

+
+
<-
+

API Changes in Apache HTTP Server 2.4 since 2.2

+
+

Available Languages:  en 

+
+ +

This document describes changes to the Apache HTTPD API from + version 2.2 to 2.4, that may be of interest to module/application + developers and core hacks. As of the first GA release of the + 2.4 branch API compatibility is preserved for the life of the + 2.4 branch. (The + VERSIONING + description for the 2.4 release provides more information about API + compatibility.)

+ +

API changes fall into two categories: APIs that are altogether new, + and existing APIs that are expanded or changed. The latter are + further divided into those where all changes are backwards-compatible + (so existing modules can ignore them), and those that might + require attention by maintainers. As with the transition from + HTTPD 2.0 to 2.2, existing modules and applications will require + recompiling and may call for some attention, but most should not + require any substantial updating (although some may be able to + take advantage of API changes to offer significant improvements).

+

For the purpose of this document, the API is split according + to the public header files. These headers are themselves the + reference documentation, and can be used to generate a browsable + HTML reference with make docs.

+
+ +
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+
+

Changed APIs

+ + +

ap_expr (NEW!)

+ +

Introduces a new API to parse and evaluate boolean and algebraic + expressions, including provision for a standard syntax and + customised variants.

+ + +

ap_listen (changed; backwards-compatible)

+ +

Introduces a new API to enable httpd child processes to serve + different purposes.

+ + +

ap_mpm (changed)

+ +

ap_mpm_run is replaced by a new mpm hook. + Also ap_graceful_stop_signalled is lost, and + ap_mpm_register_timed_callback is new.

+ + +

ap_regex (changed)

+ +

In addition to the existing regexp wrapper, a new higher-level API + ap_rxplus is now provided. This provides the capability to + compile Perl-style expressions like s/regexp/replacement/flags + and to execute them against arbitrary strings. Support for regexp + backreferences is also added.

+ + +

ap_slotmem (NEW!)

+ +

Introduces an API for modules to allocate and manage memory slots, + most commonly for shared memory.

+ + +

ap_socache (NEW!)

+ +

API to manage a shared object cache.

+ + +

heartbeat (NEW!)

+ +

common structures for heartbeat modules

+ + +

ap_parse_htaccess (changed)

+ +

The function signature for ap_parse_htaccess has been + changed. A apr_table_t of individual directives allowed + for override must now be passed (override remains).

+ + +

http_config (changed)

+ +
    +
  • Introduces per-module, per-directory loglevels, including macro wrappers.
    • +
  • New AP_DECLARE_MODULE macro to declare all modules.
    • +
  • New APLOG_USE_MODULE macro necessary for per-module loglevels in + multi-file modules.
    • +
  • New API to retain data across module unload/load
    • +
  • New check_config hook
    • +
  • New ap_process_fnmatch_configs() function to process wildcards
    • +
  • Change ap_configfile_t, ap_cfg_getline(), + ap_cfg_getc() to return error codes, and add + ap_pcfg_strerror() for retrieving an error description.
    • +
  • Any config directive permitted in ACCESS_CONF context must now + correctly handle being called from an .htaccess file via the new + AllowOverrideList directive. + ap_check_cmd_context() accepts a new flag NOT_IN_HTACCESS to detect + this case.
    • +
+ + +

http_core (changed)

+ +
    +
  • REMOVED ap_default_type, ap_requires, all + 2.2 authnz API
    • +
  • Introduces Optional Functions for logio and authnz
    • +
  • New function ap_get_server_name_for_url to support IPv6 + literals.
    • +
  • New function ap_register_errorlog_handler to register error log + format string handlers.
    • +
  • Arguments of error_log hook have changed. Declaration has moved to + http_core.h.
    • +
  • New function ap_state_query to determine if the server is in the + initial configuration preflight phase or not. This is both easier to + use and more correct than the old method of creating a pool userdata + entry in the process pool.
    • +
  • New function ap_get_conn_socket to get the socket descriptor for a + connection. This should be used instead of accessing the core + connection config directly.
    • +
+ + +

httpd (changed)

+ +
    +
  • Introduce per-directory, per-module loglevel
    • +
  • New loglevels APLOG_TRACEn
    • +
  • Introduce errorlog ids for requests and connections
    • +
  • Support for mod_request kept_body
    • +
  • Support buffering filter data for async requests
    • +
  • New CONN_STATE values
    • +
  • Function changes: ap_escape_html updated; + ap_unescape_all, ap_escape_path_segment_buffer
    • +
  • Modules that load other modules later than the EXEC_ON_READ config + reading stage need to call ap_reserve_module_slots() or + ap_reserve_module_slots_directive() in their + pre_config hook.
    • +
  • The useragent IP address per request can now be tracked + independently of the client IP address of the connection, for + support of deployments with load balancers.
    • +
+ + +

http_log (changed)

+ +
    +
  • Introduce per-directory, per-module loglevel
    • +
  • New loglevels APLOG_TRACEn
    • +
  • ap_log_*error become macro wrappers (backwards-compatible if + APLOG_MARK macro is used, except that is no longer possible to + use #ifdef inside the argument list)
    • +
  • piped logging revamped
    • +
  • module_index added to error_log hook
    • +
  • new function: ap_log_command_line
    • +
+ + +

http_request (changed)

+ +
    +
  • New auth_internal API and auth_provider API
    • +
  • New EOR bucket type
    • +
  • New function ap_process_async_request
    • +
  • New flags AP_AUTH_INTERNAL_PER_CONF and + AP_AUTH_INTERNAL_PER_URI
    • +
  • New access_checker_ex hook to apply additional access control + and/or bypass authentication.
    • +
  • New functions ap_hook_check_access_ex, + ap_hook_check_access, ap_hook_check_authn, + ap_hook_check_authz which accept + AP_AUTH_INTERNAL_PER_* flags
    • +
  • DEPRECATED direct use of ap_hook_access_checker, + access_checker_ex, ap_hook_check_user_id, + ap_hook_auth_checker
    • +
+

When possible, registering all access control hooks (including + authentication and authorization hooks) using AP_AUTH_INTERNAL_PER_CONF + is recommended. If all modules' access control hooks are registered + with this flag, then whenever the server handles an internal + sub-request that matches the same set of access control configuration + directives as the initial request (which is the common case), it can + avoid invoking the access control hooks another time.

+

If your module requires the old behavior and must perform access + control checks on every sub-request with a different URI from the + initial request, even if that URI matches the same set of access + control configuration directives, then use + AP_AUTH_INTERNAL_PER_URI.

+ + +

mod_auth (NEW!)

+ +

Introduces the new provider framework for authn and authz

+ + +

mod_cache (changed)

+ +

Introduces a commit_entity() function to the cache provider + interface, allowing atomic writes to cache. Add a cache_status() + hook to report the cache decision. All private structures and functions were + removed.

+ + +

mod_core (NEW!)

+ +

This introduces low-level APIs to send arbitrary headers, + and exposes functions to handle HTTP OPTIONS and TRACE.

+ + +

mod_cache_disk (changed)

+ +

Changes the disk format of the disk cache to support atomic cache + updates without locking. The device/inode pair of the body file is + embedded in the header file, allowing confirmation that the header + and body belong to one another.

+ + +

mod_disk_cache (renamed)

+ +

The mod_disk_cache module has been renamed to mod_cache_disk in + order to be consistent with the naming of other modules within the + server.

+ + +

mod_request (NEW!)

+ +

The API for mod_request, to make input data + available to multiple application/handler modules where required, + and to parse HTML form data.

+ + +

mpm_common (changed)

+ +
    +
  • REMOVES: accept, lockfile, lock_mech, + set_scoreboard (locking uses the new ap_mutex API)
    • +
  • NEW API to drop privileges (delegates this platform-dependent + function to modules)
    • +
  • NEW Hooks: mpm_query, timed_callback, and + get_name
    • +
  • CHANGED interfaces: monitor hook, + ap_reclaim_child_processes, + ap_relieve_child_processes
    • +
+ + +

scoreboard (changed)

+ +

ap_get_scoreboard_worker is made non-backwards-compatible + as an alternative version is introduced. Additional proxy_balancer + support. Child status stuff revamped.

+ + +

util_cookies (NEW!)

+ +

Introduces a new API for managing HTTP Cookies.

+ + +

util_ldap (changed)

+ +

no description available

+ + +

util_mutex (NEW!)

+ +

A wrapper for APR proc and global mutexes in httpd, providing + common configuration for the underlying mechanism and location + of lock files.

+ + +

util_script (changed)

+ +

NEW: ap_args_to_table

+ + +

util_time (changed)

+ +

NEW: ap_recent_ctime_ex

+ + +
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+
+

Specific information on upgrading modules from 2.2

+ + +

Logging

+ +

In order to take advantage of per-module loglevel configuration, any + source file that calls the ap_log_* functions should declare + which module it belongs to. If the module's module_struct is called + foo_module, the following code can be used to remain + backward compatible with HTTPD 2.0 and 2.2:

+

+ #include <http_log.h>
+
+ #ifdef APLOG_USE_MODULE
+ APLOG_USE_MODULE(foo);
+ #endif +

+

Note: This is absolutely required for C++-language modules. It + can be skipped for C-language modules, though that breaks + module-specific log level support for files without it.

+

The number of parameters of the ap_log_* functions and the + definition of APLOG_MARK has changed. Normally, the change + is completely transparent. However, changes are required if a + module uses APLOG_MARK as a parameter to its own functions + or if a module calls ap_log_* without passing + APLOG_MARK. A module which uses wrappers + around ap_log_* typically uses both of these constructs.

+ +

The easiest way to change code which passes APLOG_MARK to + its own functions is to define and use a different macro that expands to + the parameters required by those functions, as APLOG_MARK + should only be used when calling ap_log_* + directly. In this way, the code will remain compatible with HTTPD 2.0 + and 2.2.

+ +

Code which calls ap_log_* without passing + APLOG_MARK will necessarily differ between 2.4 and earlier + releases, as 2.4 requires a new third argument, + APLOG_MODULE_INDEX.

+ +

+ /* code for httpd 2.0/2.2 */
+ ap_log_perror(file, line, APLOG_ERR, 0, p, "Failed to allocate dynamic lock structure");
+
+ /* code for httpd 2.4 */
+ ap_log_perror(file, line, APLOG_MODULE_INDEX, APLOG_ERR, 0, p, "Failed to allocate dynamic lock structure");
+
+

+ +

ap_log_*error are now implemented as macros. This means + that it is no longer possible to use #ifdef inside the + argument list of ap_log_*error, as this would cause + undefined behavior according to C99.

+ +

A server_rec pointer must be passed to + ap_log_error() when called after startup. This + was always appropriate, but there are even more limitations with + a NULL server_rec in 2.4 than in + previous releases. Beginning with 2.3.12, the global variable + ap_server_conf can always be used as + the server_rec parameter, as it will be + NULL only when it is valid to pass NULL + to ap_log_error(). ap_server_conf + should be used only when a more appropriate server_rec + is not available.

+ +

Consider the following changes to take advantage of the new + APLOG_TRACE1..8 log levels:

+
    +
  • Check current use of APLOG_DEBUG and + consider if one of the APLOG_TRACEn levels is + more appropriate.
    • +
  • If your module currently has a mechanism for configuring + the amount of debug logging which is performed, consider + eliminating that mechanism and relying on the use of + different APLOG_TRACEn levels. If expensive + trace processing needs to be bypassed depending on the + configured log level, use the APLOGtracen + and APLOGrtracen macros to first check + if tracing is enabled.
    • +
+ +

Modules sometimes add process id and/or thread id to their log + messages. These ids are now logged by default, so it may not + be necessary for the module to log them explicitly. (Users may + remove them from the error log format, but they can be + instructed to add it back if necessary for problem diagnosis.)

+ + +

If your module uses these existing APIs...

+ + +
+
ap_default_type()
+
This is no longer available; Content-Type must be configured + explicitly or added by the application.
+ +
ap_get_server_name()
+
If the returned server name is used in a URL, + use ap_get_server_name_for_url() instead. This new + function handles the odd case where the server name is an IPv6 + literal address.
+ +
ap_get_server_version()
+
For logging purposes, where detailed information is + appropriate, use ap_get_server_description(). + When generating output, where the amount of information + should be configurable by ServerTokens, use + ap_get_server_banner().
+ +
ap_graceful_stop_signalled()
+
Replace with a call + to ap_mpm_query(AP_MPMQ_MPM_STATE) and checking for + state AP_MPMQ_STOPPING.
+ +
ap_max_daemons_limit, ap_my_generation, + and ap_threads_per_child
+
Use ap_mpm_query() query codes + AP_MPMQ_MAX_DAEMON_USED, AP_MPMQ_GENERATION, + and AP_MPMQ_MAX_THREADS, respectively.
+ +
ap_mpm_query()
+
Ensure that it is not used until after the register-hooks + hook has completed. Otherwise, an MPM built as a DSO + would not have had a chance to enable support for this + function.
+ +
ap_requires()
+
The core server now provides better infrastructure for handling + Require configuration. + Register an auth provider function for each supported entity using + ap_register_auth_provider(). The function will be + called as necessary during Require + processing. (Consult bundled modules for detailed examples.)
+ +
ap_server_conf->process->pool + userdata
+
+ Optional: +
    +
  • If your module uses this to determine which pass of the + startup hooks is being run, + use ap_state_query(AP_SQ_MAIN_STATE).
    • +
  • If your module uses this to maintain data across the + unloading and reloading of your module, use + ap_retained_data_create() and + ap_retained_data_get().
    • +
+
+ +
apr_global_mutex_create(), + apr_proc_mutex_create()
+
Optional: See ap_mutex_register(), + ap_global_mutex_create(), and + ap_proc_mutex_create(); these allow your + mutexes to be configurable with + the Mutex directive; + you can also remove any configuration mechanisms in your + module for such mutexes +
+ +
CORE_PRIVATE
+
This is now unnecessary and ignored.
+ +
dav_new_error() + and dav_new_error_tag()
+
Previously, these assumed that errno contained + information describing the failure. Now, + an apr_status_t parameter must be provided. Pass + 0/APR_SUCCESS if there is no such error information, or a valid + apr_status_t value otherwise.
+ +
mpm_default.h, DEFAULT_LOCKFILE, + DEFAULT_THREAD_LIMIT, DEFAULT_PIDLOG, + etc.
+
The header file and most of the default configuration + values set in it are no longer visible to modules. (Most can + still be overridden at build time.) DEFAULT_PIDLOG + and DEFAULT_REL_RUNTIMEDIR are now universally + available via ap_config.h.
+ +
unixd_config
+
This has been renamed to ap_unixd_config.
+ +
unixd_setup_child()
+
This has been renamed to ap_unixd_setup_child(), but most callers + should call the added ap_run_drop_privileges() hook.
+ +
conn_rec->remote_ip and + conn_rec->remote_addr
+
These fields have been renamed in order to distinguish between + the client IP address of the connection and the useragent IP address + of the request (potentially overridden by a load balancer or proxy). + References to either of these fields must be updated with one of the + following options, as appropriate for the module: +
    +
  • When you require the IP address of the user agent, which + might be connected directly to the server, or might optionally be + separated from the server by a transparent load balancer or + proxy, use request_rec->useragent_ip and + request_rec->useragent_addr.
    • +
  • When you require the IP address of the client that is + connected directly to the server, which might be the useragent or + might be the load balancer or proxy itself, use + conn_rec->client_ip and + conn_rec->client_addr.
    • +
+
+
+ + +

If your module interfaces with this feature...

+ +
+
suEXEC
+
Optional: If your module logs an error + when ap_unixd_config.suexec_enabled is 0, + also log the value of the new + field suexec_disabled_reason, which contains an + explanation of why it is not available.
+ +
Extended status data in the scoreboard
+
In previous releases, ExtendedStatus had to be + set to On, which in turn required that + mod_status was loaded. In 2.4, just + set ap_extended_status to 1 in a + pre-config hook and the extended status data will be + available.
+
+ + +

Does your module...

+ +
+
Parse query args
+
Consider if ap_args_to_table() would be + helpful.
+ +
Parse form data...
+
Use ap_parse_form_data().
+ +
Check for request header fields Content-Length + and Transfer-Encoding to see if a body was + specified
+
Use ap_request_has_body().
+ +
Implement cleanups which clear pointer variables
+
Use ap_pool_cleanup_set_null().
+ +
Create run-time files such as shared memory files, pid files, + etc.
+
Use ap_runtime_dir_relative() so that the global + configuration for the location of such files, either by the + DEFAULT_REL_RUNTIMEDIR compile setting or the + DefaultRuntimeDir directive, + will be respected. Apache httpd 2.4.2 and above.
+ +
+ + +
+
+

Available Languages:  en 

+
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+ \ No newline at end of file -- cgit v1.2.3