X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/f078f86ef3e6d0119845cdf8603b8174770cacc7..74c3d81c6581448c78c13dd33e2283fad8d04380:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 84597da83..18f92404a 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -2072,6 +2072,8 @@ withdrawn. .section "Dynamically loaded module support" "SECTdynamicmodules" .cindex "lookup modules" .cindex "router modules" +.cindex "transport modules" +.cindex "authenticator modules" .cindex "dynamic modules" .cindex ".so building" On some platforms, Exim supports not compiling all lookup types directly into @@ -2080,15 +2082,16 @@ on demand. This permits packagers to build Exim with support for lookups with extensive library dependencies without requiring all systems to install all of those dependencies. -Most, but not all, lookup types can be built this way. - .new -Similarly, router drivers can be built as external modules. -This permits a smaller exim binary, growing only as needed for the -runtime cofiguration. +Any combination of lookup types can be built this way. +Lookup types that provide several variants will be loaded as +Exim starts. +Types that provide only one method are not loaded until used by +the runtime configuration. .wen -Set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be +For building +set &`LOOKUP_MODULE_DIR`& to the directory into which the modules will be installed; Exim will only load modules from that directory, as a security measure. You will need to set &`CFLAGS_DYNAMIC`& if not already defined for your OS; see &_OS/Makefile-Linux_& for an example. @@ -2104,6 +2107,19 @@ LOOKUP_LSEARCH=yes LOOKUP_SQLITE=2 LOOKUP_MYSQL=2 .endd +Set also &`LOOKUP_`&<&'lookup_type'&>&` INCLUDE`& and +&`LOOKUP_`&<&'lookup_type'&>`_LIBS if needed for each lookup type, +ensuring that duplicates are not present in more global values. + +.new +Similarly, authenticator, router and transport drivers can be built +as external modules. +Modules will be searched for as demanded by the runtime configuration, +permitting a smaller Exim binary. + +For building, as above but using +&`AUTH_*`&, &`ROUTER_*`& and &`TRANSPORT_*`& instead of &`LOOKUP_*`&, +.wen .section "The building process" "SECID29" @@ -5459,7 +5475,7 @@ list items, it is not ignored when parsing the list. The spaces around the first colon in the example above are necessary. If they were not there, the list would be interpreted as the two items 127.0.0.1:: and 1. -.section "Changing list separators" "SECTlistsepchange" +.subsection "Changing list separators" "SECTlistsepchange" .cindex "list separator" "changing" .cindex "IPv6" "addresses in lists" Doubling colons in IPv6 addresses is an unwelcome chore, so a mechanism was @@ -5500,7 +5516,7 @@ enclosing an empty list item. -.section "Empty items in lists" "SECTempitelis" +.subsection "Empty items in lists" "SECTempitelis" .cindex "list" "empty item in" An empty item at the end of a list is always ignored. In other words, trailing separator characters are ignored. Thus, the list in @@ -8205,7 +8221,7 @@ ${lookup mysql{servers=master; UPDATE ...} } The new version avoids issues with tainted arguments explicitly expanded as part of the query. The entire string within the braces becomes tainted, -including the server sepcification - which is not permissible. +including the server specification - which is not permissible. If the older sytax is used, a warning message will be logged. This syntax will be removed in a future release. @@ -10817,7 +10833,7 @@ will sort an MX lookup into priority order. .vitem &*${srs_encode&~{*&<&'secret'&>&*}{*&<&'return&~path'&>&*}{*&<&'original&~domain'&>&*}}*& -SRS encoding. See SECT &<>& for details. +SRS encoding. See section &<>& for details. @@ -16265,7 +16281,7 @@ set. .cindex "underscore in EHLO/HELO" This option can be set to a string of rogue characters that are permitted in non-ip-literal EHLO and HELO names in addition to the standard letters, digits, -hyphens, and dots. For examplem if you really must allow underscores, +hyphens, and dots. For example if you really must allow underscores, you can set .code helo_allow_chars = _ @@ -32039,12 +32055,17 @@ This control turns off DKIM verification processing entirely. For details on the operation and configuration of DKIM, see section &<>&. -.vitem &*control&~=&~dmarc_disable_verify*& +.vitem &*control&~=&~dmarc_disable_verify*& &&& + &*control&~=&~dmarc_enable_forensic*& .cindex "disable DMARC verify" -.cindex "DMARC" "disable verify" -This control turns off DMARC verification processing entirely. For details on +.cindex DMARC "disable verify" +.cindex DMARC controls +.cindex DMARC "forensic mails" +These control affect DMARC processing. For details on the operation and configuration of DMARC, see section &<>&. +The &"disable"& turns off DMARC verification processing entirely. + .vitem &*control&~=&~dscp/*&<&'value'&> .cindex "&ACL;" "setting DSCP value" @@ -35961,7 +35982,7 @@ The third argument may be NULL, in which case the &%-oMas%& option is omitted. .vitem &*void&~debug_printf(char&~*,&~...)*& -This is Exim's debugging function, with arguments as for &'(printf()'&. The +This is Exim's debugging function, with arguments as for &'printf()'&. The output is written to the standard error stream. If no debugging is selected, calls to &'debug_printf()'& have no effect. Normally, you should make calls conditional on the &`local_scan`& debug selector by coding like this: @@ -41046,20 +41067,31 @@ will be used during message reception. .next A queue runner process retains root privilege throughout its execution. Its job is to fork a controlled sequence of delivery processes. + +.next +A delivery process retains root privilege throughout most of its execution., +including while the recipient addresses in a message are being routed. + +.ilist +However, if a user's filter file has to be processed, +this is done in a subprocess that runs under the individual user's uid and +gid. A system filter is run as root unless &%system_filter_user%& is set. +.endlist + +Any actual deliveries (that is, the transports themselves) are run in +subprocesses which always change to a non-root uid and gid. +.ilist +For local +deliveries this is typically the uid and gid of the owner of the mailbox. .next -A delivery process retains root privilege throughout most of its execution, -but any actual deliveries (that is, the transports themselves) are run in -subprocesses which always change to a non-root uid and gid. For local -deliveries this is typically the uid and gid of the owner of the mailbox; for -remote deliveries, the Exim uid and gid are used. Once all the delivery +For remote deliveries, the Exim uid and gid are used. +.endlist + +Once all the delivery subprocesses have been run, a delivery process changes to the Exim uid and gid while doing post-delivery tidying up such as updating the retry database and generating bounce and warning messages. -While the recipient addresses in a message are being routed, the delivery -process runs as root. However, if a user's filter file has to be processed, -this is done in a subprocess that runs under the individual user's uid and -gid. A system filter is run as root unless &%system_filter_user%& is set. .next A process that is testing addresses (the &%-bt%& option) runs as root so that the routing is done in the same environment as a message delivery. @@ -42298,6 +42330,12 @@ This includes retransmissions done by traditional forwarders. SPF verification support is built into Exim if SUPPORT_SPF=yes is set in &_Local/Makefile_&. The support uses the &_libspf2_& library &url(https://www.libspf2.org/). +.new +.cindex "dynamic modules" +The support can be built as a dynamic-load module if desired; +see the comments in that Makefile. +.wen + There is no Exim involvement in the transmission of messages; publishing certain DNS records is all that is required.