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Diffstat (limited to 'pod')
| -rw-r--r-- | pod/perl571delta.pod | 574 |
1 files changed, 540 insertions, 34 deletions
diff --git a/pod/perl571delta.pod b/pod/perl571delta.pod index d58384a19e..a7051fcb1d 100644 --- a/pod/perl571delta.pod +++ b/pod/perl571delta.pod @@ -10,6 +10,37 @@ This document describes differences between the 5.7.0 release and the (To view the differences between the 5.6.0 release and the 5.7.0 release, see L<perl570delta>). +=head1 Security Vulnerability Closed + +(This change was already made in 5.7.0 but bears repeating here.) + +A potential security vulnerability in the optional suidperl component +of Perl was identified in August 2000. suidperl is neither built nor +installed by default. As of April 2001 the only known vulnerable +platform is Linux, most likely all Linux distributions. CERT and +various vendors and distributors have been alerted about the vulnerability. +See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt +for more information. + +The problem was caused by Perl trying to report a suspected security +exploit attempt using an external program, /bin/mail. On Linux +platforms the /bin/mail program had an undocumented feature which +when combined with suidperl gave access to a root shell, resulting in +a serious compromise instead of reporting the exploit attempt. If you +don't have /bin/mail, or if you have 'safe setuid scripts', or if +suidperl is not installed, you are safe. + +The exploit attempt reporting feature has been completely removed from +all the Perl 5.7 releases (and will be gone also from the maintenance +release 5.6.1), so that particular vulnerability isn't there anymore. +However, further security vulnerabilities are, unfortunately, always +possible. The suidperl code is being reviewed and if deemed too risky +to continue to be supported, it may be completely removed from future +releases. In any case, suidperl should only be used by security +experts who know exactly what they are doing and why they are using +suidperl instead of some other solution such as sudo (see +http://www.courtesan.com/sudo/). + =head1 Incompatible Changes =over 4 @@ -19,20 +50,28 @@ release, see L<perl570delta>). Although "you shouldn't do that", it was possible to write code that depends on Perl's hashed key order (Data::Dumper does this). The new algorithm "One-at-a-Time" produces a different hashed key order. -More details are in L<perldelta/Performance Enhancements>. +More details are in L</"Performance Enhancements">. + +=item * + +The list of filenames from glob() (or <...>) is now by default sorted +alphabetically to be csh-compliant. (bsd_glob() does still sort platform +natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) =back +=head1 Retired Features + +The use of chop() is now deprecated. This has been made easier by +rewriting all the examples in the documentation to use chomp() instead. + =head1 Core Enhancements =over 4 =item * -Anonymous temporary files are available without need to -'use FileHandle' or other module via - - open($fh,"+>", undef) || ... +AUTOLOAD is now lvaluable. =item * @@ -55,6 +94,9 @@ platform supports it (mostly UNIXes). Layers to be applied by default may be specified via the 'open' pragma. +See L</"Installation and Configuration Improvements"> for the effects +of PerlIO on your architecture name. + =item * File handles can be marked as accepting Perl's internal encoding of Unicode @@ -75,7 +117,12 @@ File handles can be opened to "in memory" files held in Perl scalars via: =item * -Formats now support zero-padded decimal fields. +Anonymous temporary files are available without need to +'use FileHandle' or other module via + + open($fh,"+>", undef) || ... + +That is a literal undef, not an undefined value. =item * @@ -87,12 +134,238 @@ creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in the child process. =item * + +The following keywords are now overrideable: chop, chomp, each, keys, +pop, push, shift, splice, unshift. + +=item * + +Formats now support zero-padded decimal fields. + +=item * + +Perl now tries internally to use integer values in numeric conversions +and basic arithmetics (+ - * /) if the arguments are integers, and +tries also to keep the results stored internally as integers. +This change leads into often slightly faster and always less lossy +arithmetics (previously Perl always preferred floating point numbers +in its math) + +=item * The printf and sprintf now support parameter reordering using the C<%\d+\$> and C<*\d+\$> syntaxes. +=item * + +Unicode in general should be now much more usable. Unicode can be +used in hash keys, Unicode in regular expressions should work now, +Unicode in tr/// should work now (though tr/// seems to be a +particularly tricky to get right, so you have been warned) + +=item * + +The Unicode Character Database coming with Perl has been upgraded +to Unicode 3.1. + +=item * + +The Unicode character classes \p{Blank} and \p{SpacePerl} have been +added. "Blank" is like C isblank(), that is, it contains only +"horizontal whitespace" (the space character is, the newline isn't), +and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space} +isn't, since that includes the vertical tabulator character, whereas +C<\s> doesn't.) + +=back + +=head2 Modules and Pragmata + +=head2 New Modules + +=over 4 + +=item * + +B::Concise is a new compiler backend for walking the Perl syntax tree, +printing concise info about ops. The output is highly customizable, +so customizable that B::Terse has been reimplemented in terms of +B::Concise. + +=item * + +Class::ISA for reporting the search path for a class's ISA tree, +from Sean Burke, has been added. + +=item * + +Cwd has now a split personality: if possible, an extension is used, +(this will hopefully be both faster and more secure and robust) but +if not possible, the familiar Perl library implementation is used. + +=item * + +Digest, a frontend module for calculating digests (checksums), +from Gisle Aas, has been added. + +=item * + +Digest::MD5 for calculating MD5 digests (checksums), from Gisle Aas, +has been added. + +NOTE: the MD5 backward compatibility module is purposefully not +included since its use is discouraged. + +=item * + +Encode provides a mechanism to translate between different character +encodings. Support for Unicode, ISO-8859-*, ASCII, CP*, KOI8-R, and +three variants of EBCDIC are compiled in to the module. Several other +encodings (like Japanese, Chinese, and MacIntosh encodings) are +included and will be loaded at runtime. + +Any encoding supported by Encode module is also available to the +":encoding()" layer if PerlIO is used. + +=item * + +Filter::Simple is an easy-to-use frontend to Filter::Util::Call, +from Damian Conway. + +=item * + +Filter::Util::Call, from Paul Marquess, provides you with the +framework to write I<Source Filters> in Perl. For most uses +the frontend Filter::Simple is to be preferred. + +=item * + +Locale::Constants, Locale::Country, Locale::Currency, and Locale::Language, +from Neil Bowers, have been added. They provide the codes for various +locale standards, such as "fr" for France, "usd" for US Dollar, and +"jp" for Japanese. + +=item * + +MIME::Base64, from Gisle Aas, allows you to encode data in base64. + +=item * + +MIME::QuotedPrint, from Gisle Aas, allows you to encode data in +quoted-printable encoding. + +MIME::QuotedPrint has been enhanced to provide the basic methods +necessary to use it with PerlIO::Via as in : + + use MIME::QuotedPrint; + open($fh,">Via(MIME::QuotedPrint)",$path) + +=item * + +PerlIO::Scalar provides the IO to "in memory" perl scalars discussed +above. It also serves as an example of a loadable layer. + +=item * + +PerlIO::Via acts as a PerlIO layer and wraps PerlIO layer +functionality provided by a class (typically implemented in +perl code). + +=item * + +Pod::Text::Overstrike, from Joe Smith, has been added. +It converts POD data to formatted overstrike text. + +=item * + +Switch from Damian Conway has been added. After + + use Switch; + +you have switch() and case() in Perl. + +=item * + +Text::Balanced from Damian Conway has been added, for +extracting delimited text sequences from strings. + +=item * + +Tie::RefHash::Nestable, from Edward Avis, allows storing hash references +(unlike the standard Tie::Refhash) + +=item * + +XS::Typemap is a test extension that exercizes XS typemaps. +Nothing gets installed but for extension writers the code is +worth studying. + +=back + +=head2 Updated And Improved Modules and Pragmata + +=over 4 + +=item * + +B::Deparse should be now more robust (still far from providing a full +roundtrip for any random piece of Perl code). + +=item * + +Class::Struct has now compile-time features. + +=item * + +Math::BigFloat has undergone much fixing. + +=item * + +Devel::Peek now has an interface for the Perl memory statistics +(this works only if you are using perl's malloc, and if you have +compiled with debugging). + +=item * + +IO::Socket has now atmark() method, which returns true if the socket +is positioned at the out-of-band mark. The method is also exportable +as a sockatmark() function. + +=item + +IO::Socket::INET has support for ReusePort option (if your platform +suppport it). The Reuse option has now an alias, ReuseAddr. + +=item * + +Net::Ping has been greatly enhanced. + +=item * + +The C<open> pragma allows layers other than ":raw" and ":crlf" when +using PerlIO. + +=item * + +POSIX::sigaction() is now much more flexible and robust. + +=item * + +The Test module has been significantly enhanced. Its use is +greatly recommended for module writers. + +=item * + +The utf8:: name space (as in the pragma) provides various +Perl-callable functions to provide low level access to Perl's +internal Unicode representation. At the moment only length() +has been implemented. + =back +The following modules have been upgraded from CPAN: CPAN, CGI, DB::File, +Getopt::Long, Pod::Man, Pod::Text, Storable, Text-Tabs+Wrap. + =head1 Performance Enhancements =over 4 @@ -107,91 +380,317 @@ of values. Hash values output from the algorithm on a hash of all random number generation tests. According to perlbench, this change has not affected the overall speed of Perl. +=item * + +unshift() should now be noticeably faster. + =back +=head1 Utility Changes + +=over 4 + +=item * + +h2xs now produces template README. + +=item * + +s2p has been completely rewritten in Perl. (It is in fact a full +implementation of sed in Perl.) + +=item * + +xsubpp now supports OUT keyword. + +=back + +=head1 New Documentation + +=head2 perlclib + +Internal replacements for standard C library functions. + +=head2 perliol + +Internals of PerlIO with layers. + +=head2 README.aix + +Documentation on compiling Perl on AIX has been added. AIX has +several different C compilers and getting the right patchlevel +is essential. On install README.aix will be installed as L<perlaix>. + +=head2 README.bs2000 + +Documentation on compling Perl on the POSIX-BC platform (an EBCDIC +mainframe environment) has been added. + +This was formerly known as README.posix-bc but the name was considered +to be too confusing (it has nothing to do with the POSIX module or the +POSIX standard). On install README.bs2000 will be installed as L<perlbs2000>. + +=head2 README.macos + +In perl 5.7.1 (and in the 5.6.1) the MacPerl sources have been +synchronized with the standard Perl sources. To compile MacPerl +some additional steps are required, and this file documents those +steps. On install README.macos will be installed as L<perlmacos>. + +=head2 README.mpeix + +The README.mpeix has been podified, which means that this information +about compiling and using Perl on the MPE/iX miniframe platform will +on install be installed as L<perlmpeix>. + +=head2 README.solaris + +README.solaris has been created and Solaris wisdom from elsewhere +in the Perl documentation has been collected there. On install +README.solaris will be installed as L<perlsolaris>. + +=head2 README.vos + +The README.vos has been podified, which means that this information +about compiling and using Perl on the Stratus VOS miniframe platform will +on install be installed as L<perlvos>. + +=head2 Porting/repository.pod + +Documentation on how to use the Perl source repository has been added. + +=head1 Performance Enhancements + =head1 Installation and Configuration Improvements +Because PerlIO is now the default on most platforms, "-perlio" doesn't +get appended to the $Config{archname} (also known as $^O) anymore. +Instead, if you explicitly choose not to use perlio (Configure command +line option -Uuseperlio), you will get "-stdio" appended. + +Another change related to the architecture name is that "-64all" +(-Duse64bitall, or "maximally 64-bit") is appended only if your pointers +are 64 bits wide. + +APPLLIB_EXP, a less-know configuration-time definition, has been +documented. It can be used to prepend site-specific directories +to Perl's default search path (@INC), see INSTALL for information. + +Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM +has been documented in INSTALL. + +If you are on IRIX or Tru64 platforms, new profiling/debugging options +have been added, see L</perlhack> for more information about pixie and +Third Degree. + +=head2 New Or Improved Platforms + +=over 4 + +=item * + +AIX dynamic loading should be now better supported. + +=item * + +AmigaOS has been verified to be happy with Perl after a long pause. + +=item * + +MacOS Classic (MacPerl has of course been available since +perl 5.004 but now the source code bases of standard Perl +and MacPerl have been synchronised) + +=item * + +NCR MP-RAS + +=item * + +NonStop-UX + +=item * + +Amdahl UTS + +=item * + +z/OS (formerly known as OS/390, formerly known as MVS OE) has now +support for dynamic loading. This is not selected by default, +however, you must specify -Dusedl in the arguments of Configure. + +=back + +=head2 Generic Improvements + =over 4 =item * Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm) -when building the Perl binary. The only exception to this is SunOS 4.x, +when building the Perl binary. The only exception to this is SunOS 4.x, which needs them. +=item * + +Some new Configure symbols, useful for extension writers: d_cmsghdr +(for struct cmsgdhr), d_fcntl_can_lock (whether fcntl() can be used +for file locking), d_fsync, d_getitimer(), d_getpagsz (for getpagesize(), +though you should prefer POSIX::sysconf(_SC_PAGE_SIZE)), d_msghdr_s +(for struct msgdhr), need_va_copy (whether one needs to use Perl_va_copy() +to copy varargs), d_readv, d_recvmsg, d_sendmsg, sig_size (the number +of elements in an array needed to hold all the available signals), +d_sockatmark, d_strtoq, d_u32align (whether one needs to access +character data aligned by U32 sized pointers), d_ualarm, d_usleep, +d_writev. + +=item * + +Removed Configure symbols: the PDP-11 memory model settings: huge, +large, medium, models. + +=item * + +SOCKS support is now much more robust. + +=item * + +If your file system supports symbolic links you can build Perl outside +of the source directory by + + mkdir /tmp/perl/build/directory + cd /tmp/perl/build/directory + sh /path/to/perl/source/Configure -Dmksymlinks ... + +This will create in /tmp/perl/build/directory a tree of symbolic links +pointing to files in /path/to/perl/source. The original files are left +unaffected. After Configure has finished you can just say + + make all test + +and Perl will be built and tested, all in /tmp/perl/build/directory. + =back =head1 Selected Bug Fixes +Numerous memory leaks have been hunted down. Most importantly anonymous +subs used to leak quite a bit. + =over 4 =item * +Small unpredictactabilities in the order of DESTROYS have been +even small. + +=item * + +mkdir() now ignores trailing slashes in the directory name, +as mandated by POSIX. + +=item * + +The PERL5OPT environment variable didn't really work before. + +=item * + +All but the first argument of the IO syswrite() method are now optional. + +=item * + +Tie::ARRAY SPLICE method was broken. + +=item * + vec() now tries to work with characters <= 255 when possible, but it leaves higher character values in place. In that case, if vec() was used to modify the string, it is no longer considered to be utf8-encoded. =back -=head1 Core Enhancements - -=head2 New Modules +=head2 Platform Specific Changes and Fixes =over 4 =item * -Encode provides a mechanism to translate between different character -encodings. Support for Unicode, ISO-8859-*, ASCII, CP*, KOI8-R, and -three variants of EBCDIC are compiled in to the module. Several other -encodings (like Japanese, Chinese, and MacIntosh encodings) are -included and will be loaded at runtime. +Linux previously had problems related to sockaddrlen when using +accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname(). =item * -Any encoding supported by Encode module is also available to the -":encoding()" layer if PerlIO is used. +Previously DYNIX/ptx had problems in its Configure probe for +non-blocking I/O. -=item * +=back -PerlIO::Scalar provides the IO to "in memory" perl scalars discussed -above. It also serves as an example of a loadable layer. +=head1 New or Changed Diagnostics -=item * +Two new debugging options have been added: if you have compiled your +Perl with debugging, you can use the -DT and -DR options to trace +tokenizing and to add reference counts to displaying variables, +respectively. -PerlIO::Via acts as a PerlIO layer and wraps PerlIO layer -functionality provided by a class (typically implemented in -perl code). +=over 4 =item * -MIME::QuotedPrint has been enhanced to provide the basic methods -necessary to use it with PerlIO::Via as in : +If an attempt to use a (non-blessed) reference as an array element +is made, a warning is given. - use MIME::QuotedPrint; - open($fh,">Via(MIME::QuotedPrint)",$path) +=item * + +C<push @a;> and C<unshift @a;> (with no values to push or unshift) +now give a warning. This may be a problem for generated and evaled +code. =back -=head2 Updated And Improved Modules and Pragmata +=head1 Changed Internals =over 4 =item * -The C<open> pragma allows layers other than ":raw" and ":crlf" when -using PerlIO. +Some new internal APIs: ptr_table_clear, ptr_table_free, sv_setref_uv. +For the full list see L<perlapi>. =item * -The utf8:: name space (as in the pragma) provides various -Perl-callable functions to provide low level access to Perl's -internal Unicode representation. +dTHR and djSP have been obsoleted; the former removed and the latter +replaced with dSP. + +=item * + +Perl now uses system malloc instead of Perl malloc in all 64-bit platforms. =back =head1 Known Problems +=head2 lib/b test 19 + +The test fails in various platforms (PA64 and IA64 are known), but the +exact cause is still being investigated. + +=head2 Localizing a Tied Variable Leaks Memory + + use Tie::Hash; + tie my %tie_hash => 'Tie::StdHash'; + + ... + + local($tie_hash{Foo}) = 1; # leaks + +Code like the above is known to leak memory every time the local() +is executed. + +=head2 sigaction test 13 in VMS + +The test is known to fail, whether it's because of VMS of because +of faulty test, is not known. + =head2 sprintf tests 129 and 130 The op/sprintf tests 129 and 130 are known to fail in some platforms. @@ -201,6 +700,13 @@ The failing platforms do not comply with the ANSI C Standard, line something else than "1" and "-1" when formatting 0.6 and -0.6 using the printf format "%.0f", most often they produce "0" and "-0".) +=head2 Self-tying of Arrays and Hashes Is Forbidden + +Self-tying of arrays and hashes is broken in rather deep and +hard-to-fix ways. As a stop-gap measure to avoid people from getting +frustrated at the mysterious results (core dumps, most often) it is +for now forbidden (you will get a fatal error even from an attempt). + =head1 Reporting Bugs If you find what you think is a bug, you might check the articles |