Historically, this mechanism was used to process "nosegneg"
subdirectories, and it is still used to include the "tls"
subdirectories. With nosegneg support gone from ld.so, this is part
no longer useful.
The entire mechanism is not well-designed because it causes the
meaning of hwcap bits in ld.so.cache to depend on the kernel version
that was used to generate the cache, which makes it difficult to use
this mechanism for anything else in the future.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
With this patch, -v turns on a "from" trace for each directory
searched, that tells you WHY that directory is being searched -
is it a builtin, from the command line, or from some config file?
I've updated copyright dates in glibc for 2020. This is the patch for
the changes not generated by scripts/update-copyrights and subsequent
build / regeneration of generated files. As well as the usual annual
updates, mainly dates in --version output (minus libc.texinfo which
previously had to be handled manually but is now successfully updated
by update-copyrights), there is a fix to
sysdeps/unix/sysv/linux/powerpc/bits/termios-c_lflag.h where a typo in
the copyright notice meant it failed to be updated automatically.
Please remember to include 2020 in the dates for any new files added
in future (which means updating any existing uncommitted patches you
have that add new files to use the new copyright dates in them).
This patch adds fall-through comments in some cases where -Wextra
produces implicit-fallthrough warnings.
The patch is non-exhaustive. Apart from architecture-specific code
for non-x86_64 architectures, it does not change sunrpc/xdr.c (legacy
code, probably should have such changes, but left to be dealt with
separately), or places that already had comments about the
fall-through but not matching the form expected by
-Wimplicit-fallthrough=3 (the default level with -Wextra; my
inclination is to adjust those comments to match rather than
downgrading to -Wimplicit-fallthrough=1 to allow any comment), or one
place where I thought the implicit fallthrough was not correct and so
should be handled separately as a bug fix. I think the key thing to
consider in review of this patch is whether the fall-through is indeed
intended and correct in each place where such a comment is added.
Tested for x86_64.
* elf/dl-exception.c (_dl_exception_create_format): Add
fall-through comments.
* elf/ldconfig.c (parse_conf_include): Likewise.
* elf/rtld.c (print_statistics): Likewise.
* locale/programs/charmap.c (parse_charmap): Likewise.
* misc/mntent_r.c (__getmntent_r): Likewise.
* posix/wordexp.c (parse_arith): Likewise.
(parse_backtick): Likewise.
* resolv/ns_ttl.c (ns_parse_ttl): Likewise.
* sysdeps/x86/cpu-features.c (init_cpu_features): Likewise.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
ldconfig supports `include' directives and use the glob function to
process them. The glob function sort entries according to the LC_COLLATE
category. When using a standard "include /etc/ld.so.conf.d/*.conf" entry
in /etc/ld.so.conf, the order therefore depends on the locale used to
run ldconfig. A few examples of locale specific order that might be
disturbing in that context compared to the C locale:
- The cs_CZ and sk_SK locales sort the digits after the letters.
- The et_EE locale sorts the 'z' between 's' and 't'.
This patch fixes that by setting LC_COLLATE to C in order to process
files in deterministic order, independently of the locale used to launch
ldconfig.
NOTE: This should NOT be backported to older release branches.
Changelog:
[BZ #22505]
* elf/ldconfig.c (main): Call setlocale to force LC_COLLATE to C.
Developers creating development packages must take care
to have their static linker DSO link point to the actual
SONAME file. This allows ldconfig to correctly create
the required links for the SONAME. The behaviour is now
more clearly documented in a code comment added by this
patch.
In dl-hwcaps.c the comment read that rounding was done
to ElfW(Addr), but it's actually rounded to ElfW(Word).
In ldconfig.c we make each comment a sentence and
mention that the "tls" pseudo-hwcap is just for legacy
installations where TLS was optional.
---
2013-05-22 Carlos O'Donell <carlos@redhat.com>
* elf/ldconfig.c (is_hwcap_platform): Make comments full setences.
(main): Mention "tls" pseudo-hwcap is legacy.
* elf/dl-hwcaps.c (_dl_important_hwcaps): Correct rounding comment.
Loading of the vDSO pseudo-hwcap from the type 2 GNU note is
a rather arcane and poorly documented process. Given that I had
a chance to review this code today I thought I would add all
of the things I had to lookup to verify the validity of the
process.
With a single .note.GNU the vDSO can register up to 64 flags,
though in practice you are limited to 64 - _DL_FIRST_EXTRA
bits which on x86 is 12 bits.
The only use of this that I know of is in the Xen support
in Linux where they use the 1st bit to indicate "nosegneg".
I see "We use bit 1 to avoid bugs in some versions of glibc
when bit 0 is used; the choice is otherwise arbitrary.", but
no reference to a glibc bug anywhere. The code as-is should
support bit zero, so we still have that free for future use.
The kernel, glibc, and ld.so.cache must coordinate to ensure
that bit values don't go too high and are used consistently.
---
2013-05-13 Carlos O'Donell <carlos@redhat.com>
* elf/dl-hwcaps.c (_dl_important_hwcaps): Comment vDSO hwcap loading.
* elf/ldconfig.c (is_hwcap_platform): Comment each hwcap check.
(main): Comment "tls" pseudo-hwcap.
The aux_cache fix of bug 11149 introduced a new bug - normally,
ldconfig -r never cares if the auxiliary cache is not available and
that is not a fatal problem, however this is not the case in case
of ldconfig -r when executed as non-root. In that case, ldconfig -r
fails hard unless var/cache/ldconfig/ exists within the chroot. This
patch fixes that.
Conflicts:
ChangeLog
* elf/ldd.bash.in: Likewise.
* elf/sprof.c: Likewise.
* locale/programs/locale.c: Likewise.
* malloc/memusage.sh: Likewise.
* nss/getent.c: Likewise.
2009-02-06 Joseph Myers <joseph@codesourcery.com>
* debug/pcprofiledump.c (print_version,
argp_program_version_hook): New function.
* elf/ldconfig.c (more_help): New function.
(argp): Use it.
* elf/sln.c (usage): New function.
(main): Support --help and --version.
* malloc/memusagestat.c (print_version): New function.
(argp_program_version_hook): New variable.
* nscd/nscd.c (more_help): New function.
(argp): Use it.
* posix/getconf.c (main): Send --version output to stdout.
Support --help.
* sunrpc/rpc_main.c (usage, options_usage): Take STREAM and STATUS
arguments. All callers changed.
(print_version): New function.
(parseargs): Support --help and --version.
* sunrpc/rpcinfo.c (usage): Take STREAM argument. All callers
changed.
(print_version): New function.
(main): Use getopt_long. Support --help and --version.
* sysdeps/unix/sysv/linux/lddlibc4.c (main): Support --help and
--version.
2009-02-06 Ulrich Drepper <drepper@redhat.com>
* elf/ldconfig.c (search_dir): Fix 2 off-by-2 errors.
Reported by David Anderson <davea42@earthlink.net>.
2007-04-13 Jakub Jelinek <jakub@redhat.com>
[BZ #4344]
* elf/ldconfig.c (search_dir): Fix 2 off-by-2 errors.
Reported by David Anderson <davea42@earthlink.net>.
