Commit Graph

1696 Commits

Author SHA1 Message Date
Paul Eggert
57581acd95 Fix bsearch, qsort doc to match POSIX better
* manual/search.texi (Array Search Function):
Correct the statement about lfind’s mean runtime:
it is proportional to a number (not that number),
and this is true only if random elements are searched for.
Relax the constraint on bsearch’s array argument:
POSIX says it need not be sorted, only partially sorted.
Say that the first arg passed to bsearch’s comparison function
is the key, and the second arg is an array element, as
POSIX requires.  For bsearch and qsort, say that the
comparison function should not alter the array, as POSIX
requires.  For qsort, say that the comparison function
must define a total order, as POSIX requires, that
it should not depend on element addresses, that
the original array index can be used for stable sorts,
and that if qsort still works if memory allocation fails.
Be more consistent in calling the array elements
“elements” rather than “objects”.

Co-authored-by: Zack Weinberg <zack@owlfolio.org>
2024-04-06 10:10:32 -07:00
Stafford Horne
3db9d208dd misc: Add support for Linux uio.h RWF_NOAPPEND flag
In Linux 6.9 a new flag is added to allow for Per-io operations to
disable append mode even if a file was opened with the flag O_APPEND.
This is done with the new RWF_NOAPPEND flag.

This caused two test failures as these tests expected the flag 0x00000020
to be unused.  Adding the flag definition now fixes these tests on Linux
6.9 (v6.9-rc1).

  FAIL: misc/tst-preadvwritev2
  FAIL: misc/tst-preadvwritev64v2

This patch adds the flag, adjusts the test and adds details to
documentation.

Link: https://lore.kernel.org/all/20200831153207.GO3265@brightrain.aerifal.cx/
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-04 09:41:27 +01:00
Alejandro Colomar
95c70fd0d4 manual: significand() uses FLT_RADIX, not 2
It's implemented using scalb(), which uses FLT_RADIX, AFAIK.

Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#mf21ab57e16b92eb6be6c7df79dc0eb43d4454056>
Reported-by: Morten Welinder <mwelinder@gmail.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Vincent Lefevre <vincent@vinc17.net>
Cc: DJ Delorie <dj@redhat.com>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-03 09:16:22 -03:00
Alejandro Colomar
e01b3b86e8 manual: Clarify return value of cbrt(3)
Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#mff0ab388000c6afdb5e5162804d4a0073de481de>
Reported-by: Morten Welinder <mwelinder@gmail.com>
Cowritten-by: Morten Welinder <mwelinder@gmail.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Vincent Lefevre <vincent@vinc17.net>
Cc: DJ Delorie <dj@redhat.com>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-03 09:16:22 -03:00
Alejandro Colomar
077613291b manual: floor(log2(fabs(x))) has rounding errors
Link: <https://inbox.sourceware.org/libc-alpha/20240305150131.GD3653@qaa.vinc17.org/T/#m3ceecda630012995339bcc5448fee451cf277a8b>
Reported-by: Vincent Lefevre <vincent@vinc17.net>
Suggested-by: Vincent Lefevre <vincent@vinc17.net>
Reviewed-by: DJ Delorie <dj@redhat.com>
Cc: Morten Welinder <mwelinder@gmail.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
2024-04-03 09:16:22 -03:00
Alejandro Colomar
b7d15bd1f0 manual: logb(x) is floor(log2(fabs(x)))
log2(3) doesn't accept negative input, but it seems logb(3) does accept
it.

Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#u>
Reported-by: Morten Welinder <mwelinder@gmail.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Vincent Lefevre <vincent@vinc17.net>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
2024-04-03 09:16:22 -03:00
Adhemerval Zanella
a4ed0471d7 Always define __USE_TIME_BITS64 when 64 bit time_t is used
It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI.  Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).

The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi

[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign

Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-02 15:28:36 -03:00
Joe Talbott
d370155b9a manual/tunables - Add entry for enable_secure tunable. 2024-03-01 17:43:03 +00:00
Askar Safin
dbae3a3940 trivial doc fix: remove weird phrase "syscall takes zero to five arguments"
"number of arguments, from zero to five" is wrong, because on Linux maximal number
of arguments is 6, not 5. Also, maximal number of arguments is kernel-dependent,
so let's not include it here at all.

Moreover, "Each kind of system call has a definite number of arguments" is questionable.
Think about SYS_open on Linux, which takes 2 or 3 arguments. Or SYS_clone on Linux x86_64, which
takes 2 to 5 arguments. So I propose to fully remove this sentence.

Signed-off-by: Askar Safin <safinaskar@zohomail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-02-14 12:21:03 -03:00
Paul Eggert
e7b90e6e60 stdlib: fix qsort example in manual
* manual/search.texi (Comparison Functions, Array Sort Function):
Sort an array of long ints, not doubles, to avoid hassles
with NaNs.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2024-02-01 17:54:21 -08:00
Jakub Jelinek
c62b6265a6 manual: Fix up stdbit.texi
My recent change broke make pdf and in other documentation formats
results in weird rendering and invalid URL, all because of a forgotten
comma to separate @uref arguments.
2024-02-01 16:36:55 +01:00
Joseph Myers
42cc619dfb Refer to C23 in place of C2X in glibc
WG14 decided to use the name C23 as the informal name of the next
revision of the C standard (notwithstanding the publication date in
2024).  Update references to C2X in glibc to use the C23 name.

This is intended to update everything *except* where it involves
renaming files (the changes involving renaming tests are intended to
be done separately).  In the case of the _ISOC2X_SOURCE feature test
macro - the only user-visible interface involved - support for that
macro is kept for backwards compatibility, while adding
_ISOC23_SOURCE.

Tested for x86_64.
2024-02-01 11:02:01 +00:00
Jakub Jelinek
da89496337 Use gcc __builtin_stdc_* builtins in stdbit.h if possible
The following patch uses the GCC 14 __builtin_stdc_* builtins in stdbit.h
for the type-generic macros, so that when compiled with GCC 14 or later,
it supports not just 8/16/32/64-bit unsigned integers, but also 128-bit
(if target supports them) and unsigned _BitInt (any supported precision).
And so that the macros don't expand arguments multiple times and can be
evaluated in constant expressions.

The new testcase is gcc's gcc/testsuite/gcc.dg/builtin-stdc-bit-1.c
adjusted to test stdbit.h and the type-generic macros in there instead
of the builtins and adjusted to use glibc test framework rather than
gcc style tests with __builtin_abort ().

Signed-off-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Joseph Myers <josmyers@redhat.com>
2024-01-31 19:17:27 +01:00
Andreas K. Hüttel
068b04eaed
INSTALL, install.texi: minor updates, regenerate
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2024-01-31 00:13:43 +01:00
Andreas K. Hüttel
1eed32f366
contrib.texi: update
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2024-01-30 23:48:12 +01:00
Joe Simmons-Talbott
7765034db2
manual/io: Fix swapped reading and writing phrase.
Reviewed-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2024-01-30 20:10:38 +01:00
Dennis Brendel
c06c8aeb61 manual: fix order of arguments of memalign and aligned_alloc (Bug 27547)
On the summary page the order of the function arguments was reversed, but it is
in correct order in the other places of the manual.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2024-01-24 12:10:38 -05:00
Florian Weimer
486452affb manual, NEWS: Document malloc side effect of dynamic TLS changes
The increased malloc subsystem usage is a side effect of
commit d2123d6827 ("elf: Fix slow tls
access after dlopen [BZ #19924]").

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-01-24 09:34:15 +01:00
Adhemerval Zanella
709fbd3ec3 stdlib: Reinstate stable mergesort implementation on qsort
The mergesort removal from qsort implementation (commit 03bf8357e8)
had the side-effect of making sorting nonstable.  Although neither
POSIX nor C standard specify that qsort should be stable, it seems
that it has become an instance of Hyrum's law where multiple programs
expect it.

Also, the resulting introsort implementation is not faster than
the previous mergesort (which makes the change even less appealing).

This patch restores the previous mergesort implementation, with the
exception of machinery that checks the resulting allocation against
the _SC_PHYS_PAGES (it only adds complexity and the heuristic not
always make sense depending on the system configuration and load).
The alloca usage was replaced with a fixed-size buffer.

For the fallback mechanism, the implementation uses heapsort.  It is
simpler than quicksort, and it does not suffer from adversarial
inputs.  With memory overcommit, it should be rarely triggered.

The drawback is mergesort requires O(n) extra space, and since it is
allocated with malloc the function is AS-signal-unsafe.  It should be
feasible to change it to use mmap, although I am not sure how urgent
it is.  The heapsort is also nonstable, so programs that require a
stable sort would still be subject to this latent issue.

The tst-qsort5 is removed since it will not create quicksort adversarial
inputs with the current qsort_r implementation.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
2024-01-15 15:58:35 -03:00
Adhemerval Zanella
a0cfc48e8a i386: Fail if configured with --enable-cet
Since it is only supported for x86_64.

Checked on i686-linux-gnu.
2024-01-09 13:55:51 -03:00
Adhemerval Zanella
460860f457 Remove ia64-linux-gnu
Linux 6.7 removed ia64 from the official tree [1], following the general
principle that a glibc port needs upstream support for the architecture
in all the components it depends on (binutils, GCC, and the Linux
kernel).

Apart from the removal of sysdeps/ia64 and sysdeps/unix/sysv/linux/ia64,
there are updates to various comments referencing ia64 for which removal
of those references seemed appropriate. The configuration is removed
from README and build-many-glibcs.py.

The CONTRIBUTED-BY, elf/elf.h, manual/contrib.texi (the porting
mention), *.po files, config.guess, and longlong.h are not changed.

For Linux it allows cleanup some clone2 support on multiple files.

The following bug can be closed as WONTFIX: BZ 22634 [2], BZ 14250 [3],
BZ 21634 [4], BZ 10163 [5], BZ 16401 [6], and BZ 11585 [7].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=43ff221426d33db909f7159fdf620c3b052e2d1c
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=22634
[3] https://sourceware.org/bugzilla/show_bug.cgi?id=14250
[4] https://sourceware.org/bugzilla/show_bug.cgi?id=21634
[5] https://sourceware.org/bugzilla/show_bug.cgi?id=10163
[6] https://sourceware.org/bugzilla/show_bug.cgi?id=16401
[7] https://sourceware.org/bugzilla/show_bug.cgi?id=11585
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2024-01-08 17:09:36 -03:00
H.J. Lu
848746e88e elf: Add ELF_DYNAMIC_AFTER_RELOC to rewrite PLT
Add ELF_DYNAMIC_AFTER_RELOC to allow target specific processing after
relocation.

For x86-64, add

 #define DT_X86_64_PLT     (DT_LOPROC + 0)
 #define DT_X86_64_PLTSZ   (DT_LOPROC + 1)
 #define DT_X86_64_PLTENT  (DT_LOPROC + 3)

1. DT_X86_64_PLT: The address of the procedure linkage table.
2. DT_X86_64_PLTSZ: The total size, in bytes, of the procedure linkage
table.
3. DT_X86_64_PLTENT: The size, in bytes, of a procedure linkage table
entry.

With the r_addend field of the R_X86_64_JUMP_SLOT relocation set to the
memory offset of the indirect branch instruction.

Define ELF_DYNAMIC_AFTER_RELOC for x86-64 to rewrite the PLT section
with direct branch after relocation when the lazy binding is disabled.

PLT rewrite is disabled by default since SELinux may disallow modifying
code pages and ld.so can't detect it in all cases.  Use

$ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=1

to enable PLT rewrite with 32-bit direct jump at run-time or

$ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=2

to enable PLT rewrite with 32-bit direct jump and on APX processors with
64-bit absolute jump at run-time.

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2024-01-05 05:49:49 -08:00
H.J. Lu
bbfb54930c i386: Ignore --enable-cet
Since shadow stack is only supported for x86-64, ignore --enable-cet for
i386.  Always setting $(enable-cet) for i386 to "no" to support

ifneq ($(enable-cet),no)

in x86 Makefiles.  We can't use

ifeq ($(enable-cet),yes)

since $(enable-cet) can be "yes", "no" or "permissive".
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-01-04 06:08:55 -08:00
Joseph Myers
b34b46b880 Implement C23 <stdbit.h>
C23 adds a header <stdbit.h> with various functions and type-generic
macros for bit-manipulation of unsigned integers (plus macro defines
related to endianness).  Implement this header for glibc.

The functions have both inline definitions in the header (referenced
by macros defined in the header) and copies with external linkage in
the library (which are implemented in terms of those macros to avoid
duplication).  They are documented in the glibc manual.  Tests, as
well as verifying results for various inputs (of both the macros and
the out-of-line functions), verify the types of those results (which
showed up a bug in an earlier version with the type-generic macro
stdc_has_single_bit wrongly returning a promoted type), that the
macros can be used at top level in a source file (so don't use ({})),
that they evaluate their arguments exactly once, and that the macros
for the type-specific functions have the expected implicit conversions
to the relevant argument type.

Jakub previously referred to -Wconversion warnings in type-generic
macros, so I've included a test with -Wconversion (but the only
warnings I saw and fixed from that test were actually in inline
functions in the <stdbit.h> header - not anything coming from use of
the type-generic macros themselves).

This implementation of the type-generic macros does not handle
unsigned __int128, or unsigned _BitInt types with a width other than
that of a standard integer type (and C23 doesn't require the header to
handle such types either).  Support for those types, using the new
type-generic built-in functions Jakub's added for GCC 14, can
reasonably be added in a followup (along of course with associated
tests).

This implementation doesn't do anything special to handle C++, or have
any tests of functionality in C++ beyond the existing tests that all
headers can be compiled in C++ code; it's not clear exactly what form
this header should take in C++, but probably not one using macros.

DIS ballot comment AT-107 asks for the word "count" to be added to the
names of the stdc_leading_zeros, stdc_leading_ones,
stdc_trailing_zeros and stdc_trailing_ones functions and macros.  I
don't think it's likely to be accepted (accepting any technical
comments would mean having an FDIS ballot), but if it is accepted at
the WG14 meeting (22-26 January in Strasbourg, starting with DIS
ballot comment handling) then there would still be time to update
glibc for the renaming before the 2.39 release.

The new functions and header are placed in the stdlib/ directory in
glibc, rather than creating a new toplevel stdbit/ or putting them in
string/ alongside ffs.

Tested for x86_64 and x86.
2024-01-03 12:07:14 +00:00
Paul Eggert
dff8da6b3e Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Bruno Haible
e55599e028 manual: Clarify undefined behavior of feenableexcept (BZ 31019)
Explain undefined behavior of feenableexcept in a special case.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-12-19 15:12:38 -03:00
Adhemerval Zanella
9c96c87d60 elf: Ignore GLIBC_TUNABLES for setuid/setgid binaries
The tunable privilege levels were a retrofit to try and keep the malloc
tunable environment variables' behavior unchanged across security
boundaries.  However, CVE-2023-4911 shows how tricky can be
tunable parsing in a security-sensitive environment.

Not only parsing, but the malloc tunable essentially changes some
semantics on setuid/setgid processes.  Although it is not a direct
security issue, allowing users to change setuid/setgid semantics is not
a good security practice, and requires extra code and analysis to check
if each tunable is safe to use on all security boundaries.

It also means that security opt-in features, like aarch64 MTE, would
need to be explicit enabled by an administrator with a wrapper script
or with a possible future system-wide tunable setting.

Co-authored-by: Siddhesh Poyarekar  <siddhesh@sourceware.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
2023-11-21 16:15:42 -03:00
Adhemerval Zanella
6c6fce572f elf: Remove /etc/suid-debug support
Since malloc debug support moved to a different library
(libc_malloc_debug.so), the glibc.malloc.check requires preloading the
debug library to enable it.  It means that suid-debug support has not
been working since 2.34.

To restore its support, it would require to add additional information
and parsing to where to find libc_malloc_debug.so.

It is one thing less that might change AT_SECURE binaries' behavior
due to environment configurations.

Checked on x86_64-linux-gnu.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-11-21 16:15:42 -03:00
Carlos O'Donell
3cbaacdfd2 manual: Fix termios.c example. (Bug 31078)
Remove the unused 'char *name;' from the example.

Use write instead of putchar to write input as it is read.

Example tested on x86_64 by compiling and running the example.

Tested by building the manual pdf and reviewing the results.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-11-20 16:42:23 -05:00
Wilco Dijkstra
2f5524cc53 AArch64: Remove Falkor memcpy
The latest implementations of memcpy are actually faster than the Falkor
implementations [1], so remove the falkor/phecda ifuncs for memcpy and
the now unused IS_FALKOR/IS_PHECDA defines.

[1] https://sourceware.org/pipermail/libc-alpha/2022-December/144227.html

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-11-13 16:52:50 +00:00
Paul Eggert
d1dcb565a1 Fix type typo in “String/Array Conventions” doc
* manual/string.texi (String/Array Conventions):
Fix typo reported by Alejandro Colomar <alx@kernel.org> in:
https://sourceware.org/pipermail/libc-alpha/2023-November/152646.html
2023-11-08 18:20:09 -08:00
Adhemerval Zanella
bf033c0072 elf: Add glibc.mem.decorate_maps tunable
The PR_SET_VMA_ANON_NAME support is only enabled through a configurable
kernel switch, mainly because assigning a name to a
anonymous virtual memory area might prevent that area from being
merged with adjacent virtual memory areas.

For instance, with the following code:

   void *p1 = mmap (NULL,
                    1024 * 4096,
                    PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANONYMOUS,
                    -1,
                    0);

   void *p2 = mmap (p1 + (1024 * 4096),
                    1024 * 4096,
                    PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANONYMOUS,
                    -1,
                    0);

The kernel will potentially merge both mappings resulting in only one
segment of size 0x800000.  If the segment is names with
PR_SET_VMA_ANON_NAME with different names, it results in two mappings.

Although this will unlikely be an issue for pthread stacks and malloc
arenas (since for pthread stacks the guard page will result in
a PROT_NONE segment, similar to the alignment requirement for the arena
block), it still might prevent the mmap memory allocated for detail
malloc.

There is also another potential scalability issue, where the prctl
requires
to take the mmap global lock which is still not fully fixed in Linux
[1] (for pthread stacks and arenas, it is mitigated by the stack
cached and the arena reuse).

So this patch disables anonymous mapping annotations as default and
add a new tunable, glibc.mem.decorate_maps, can be used to enable
it.

[1] https://lwn.net/Articles/906852/

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: DJ Delorie <dj@redhat.com>
2023-11-07 10:27:57 -03:00
Adhemerval Zanella
03bf8357e8 stdlib: Remove use of mergesort on qsort (BZ 21719)
This patch removes the mergesort optimization on qsort implementation
and uses the introsort instead.  The mergesort implementation has some
issues:

  - It is as-safe only for certain types sizes (if total size is less
    than 1 KB with large element sizes also forcing memory allocation)
    which contradicts the function documentation.  Although not required
    by the C standard, it is preferable and doable to have an O(1) space
    implementation.

  - The malloc for certain element size and element number adds
    arbitrary latency (might even be worse if malloc is interposed).

  - To avoid trigger swap from memory allocation the implementation
    relies on system information that might be virtualized (for instance
    VMs with overcommit memory) which might lead to potentially use of
    swap even if system advertise more memory than actually has.  The
    check also have the downside of issuing syscalls where none is
    expected (although only once per execution).

  - The mergesort is suboptimal on an already sorted array (BZ#21719).

The introsort implementation is already optimized to use constant extra
space (due to the limit of total number of elements from maximum VM
size) and thus can be used to avoid the malloc usage issues.

Resulting performance is slower due the usage of qsort, specially in the
worst-case scenario (partialy or sorted arrays) and due the fact
mergesort uses a slight improved swap operations.

This change also renders the BZ#21719 fix unrequired (since it is meant
to fix the sorted input performance degradation for mergesort).  The
manual is also updated to indicate the function is now async-cancel
safe.

Checked on x86_64-linux-gnu.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-10-31 14:18:05 -03:00
Adhemerval Zanella
e3397cae92 crypt: Remove manul entry for --enable-crypt 2023-10-31 10:59:04 -03:00
Adhemerval Zanella
e6e3c66688 crypt: Remove libcrypt support
All the crypt related functions, cryptographic algorithms, and
make requirements are removed,  with only the exception of md5
implementation which is moved to locale folder since it is
required by localedef for integrity protection (libc's
locale-reading code does not check these, but localedef does
generate them).

Besides thec code itself, both internal documentation and the
manual is also adjusted.  This allows to remove both --enable-crypt
and --enable-nss-crypt configure options.

Checked with a build for all affected ABIs.

Co-authored-by: Zack Weinberg <zack@owlfolio.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-10-30 13:03:59 -03:00
Noah Goldstein
d90b43a4ed x86: Add support for AVX10 preset and vec size in cpu-features
This commit add support for the new AVX10 cpu features:
https://cdrdv2-public.intel.com/784267/355989-intel-avx10-spec.pdf

We add checks for:
    - `AVX10`: Check if AVX10 is present.
    - `AVX10_{X,Y,Z}MM`: Check if a given vec class has AVX10 support.

`make check` passes and cpuid output was checked against GNR/DMR on an
emulator.
2023-09-29 14:18:42 -05:00
Joseph Myers
cdbf8229bb C2x scanf %wN, %wfN support
ISO C2x defines scanf length modifiers wN (for intN_t / int_leastN_t /
uintN_t / uint_leastN_t) and wfN (for int_fastN_t / uint_fastN_t).
Add support for those length modifiers, similar to the printf support
previously added.

Tested for x86_64 and x86.
2023-09-28 17:28:15 +00:00
Florian Weimer
d99609a3eb manual: Fix ld.so diagnostics menu/section structure
And shorten the section/node names a bit, so that the menu
entries become easier to read.

Texinfo 6.5 fails to process the previous structure:

./dynlink.texi:56: warning: node `Dynamic Linker Introspection' is
  next for `Dynamic Linker Diagnostics' in sectioning but not in menu
./dynlink.texi:56: warning: node up `Dynamic Linker Diagnostics'
  in menu `Dynamic Linker Invocation' and
  in sectioning `Dynamic Linker' differ
./dynlink.texi:1: node `Dynamic Linker' lacks menu item for
  `Dynamic Linker Diagnostics' despite being its Up target
./dynlink.texi:226: warning: node prev `Dynamic Linker Introspection' in menu `Dynamic Linker Invocation'
  and in sectioning `Dynamic Linker Diagnostics' differ

Texinfo 7.0.2 does not report an error.

This fixes commit f21962ddfc
("manual: Document ld.so --list-diagnostics output").

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2023-09-06 18:37:21 +02:00
Adhemerval Zanella Netto
e7190fc73d linux: Add pidfd_getpid
This interface allows to obtain the associated process ID from the
process file descriptor.  It is done by parsing the procps fdinfo
information.  Its prototype is:

   pid_t pidfd_getpid (int fd)

It returns the associated pid or -1 in case of an error and sets the
errno accordingly.  The possible errno values are those from open, read,
and close (used on procps parsing), along with:

   - EBADF if the FD is negative, does not have a PID associated, or if
     the fdinfo fields contain a value larger than pid_t.

   - EREMOTE if the PID is in a separate namespace.

   - ESRCH if the process is already terminated.

Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-09-05 13:08:59 -03:00
Adhemerval Zanella Netto
0d6f9f6265 posix: Add pidfd_spawn and pidfd_spawnp (BZ 30349)
Returning a pidfd allows a process to keep a race-free handle for a
child process, otherwise, the caller will need to either use pidfd_open
(which still might be subject to TOCTOU) or keep the old racy interface
base on pid_t.

To correct use pifd_spawn, the kernel must support not only returning
the pidfd with clone/clone3 but also waitid (P_PIDFD) (added on Linux
5.4).  If kernel does not support the waitid, pidfd return ENOSYS.
It avoids the need to racy workarounds, such as reading the procfs
fdinfo to get the pid to use along with other wait interfaces.

These interfaces are similar to the posix_spawn and posix_spawnp, with
the only difference being it returns a process file descriptor (int)
instead of a process ID (pid_t).  Their prototypes are:

  int pidfd_spawn (int *restrict pidfd,
                   const char *restrict file,
                   const posix_spawn_file_actions_t *restrict facts,
                   const posix_spawnattr_t *restrict attrp,
                   char *const argv[restrict],
                   char *const envp[restrict])

  int pidfd_spawnp (int *restrict pidfd,
                    const char *restrict path,
                    const posix_spawn_file_actions_t *restrict facts,
                    const posix_spawnattr_t *restrict attrp,
                    char *const argv[restrict_arr],
                    char *const envp[restrict_arr]);

A new symbol is used instead of a posix_spawn extension to avoid
possible issues with language bindings that might track the return
argument lifetime.  Although on Linux pid_t and int are interchangeable,
POSIX only states that pid_t should be a signed integer.

Both symbols reuse the posix_spawn posix_spawn_file_actions_t and
posix_spawnattr_t, to void rehash posix_spawn API or add a new one. It
also means that both interfaces support the same attribute and file
actions, and a new flag or file action on posix_spawn is also added
automatically for pidfd_spawn.

Also, using posix_spawn plumbing allows the reusing of most of the
current testing with some changes:

  - waitid is used instead of waitpid since it is a more generic
    interface.

  - tst-posix_spawn-setsid.c is adapted to take into consideration that
    the caller can check for session id directly.  The test now spawns
itself and writes the session id as a file instead.

  - tst-spawn3.c need to know where pidfd_spawn is used so it keeps an
    extra file description unused.

Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-09-05 13:08:59 -03:00
Florian Weimer
3d9265467e elf: Check that --list-diagnostics output has the expected syntax
Parts of elf/tst-rtld-list-diagnostics.py have been copied from
scripts/tst-ld-trace.py.

The abnf module is entirely optional and used to verify the
ABNF grammar as included in the manual.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-08-25 14:19:16 +02:00
Florian Weimer
f21962ddfc manual: Document ld.so --list-diagnostics output
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-08-25 14:15:28 +02:00
Mark Wielaard
5a21cefd5a manual/jobs.texi: Add missing @item EPERM for getpgid
The missing @item makes it look like errno will be set to ESRCH
if a cross-session getpgid is not permitted.

Found by ulfvonbelow on irc.
2023-08-25 11:43:30 +02:00
Mahesh Bodapati
21841f0d56 PowerPC: Influence cpu/arch hwcap features via GLIBC_TUNABLES
This patch enables the option to influence hwcaps used by PowerPC.
The environment variable, GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,-zzz....,
can be used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature xxx
and zzz, where the feature name is case-sensitive and has to match the ones
mentioned in the file{sysdeps/powerpc/dl-procinfo.c}.

Note that the hwcap tunables only used in the IFUNC selection.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-08-01 07:41:17 -05:00
Andreas K. Hüttel
1822328274
install.texi: Build was tested with binutils 2.41 (just released)
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2023-07-30 19:31:41 +02:00
Andreas K. Hüttel
14126ff059
install.texi: Update versions of most recent build tools
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2023-07-27 23:00:59 +02:00
Andreas K. Hüttel
1d5355ddbb
contrib.texi: Update for 2.38
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2023-07-27 21:42:57 +02:00
H.J. Lu
1547d6a64f <sys/platform/x86.h>: Add APX support
Add support for Intel Advanced Performance Extensions:

https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html

to <sys/platform/x86.h>.
2023-07-27 08:42:32 -07:00
Siddhesh Poyarekar
6c85c5a177
configure: Disable building libcrypt by default
We mentioned eventual dropping of libcrypt in the 2.28 NEWS.  Actually
put that plan in motion by first disabling building libcrypt by default.
note in NEWS that the library will be dropped completely in a future
release.

Also add a couple of builds into build-many-glibcs.py.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Andreas K. Hüttel <dilfridge@gentoo.org>
2023-07-20 20:38:13 +02:00
Siddhesh Poyarekar
c6cb8783b5 configure: Use autoconf 2.71
Bump autoconf requirement to 2.71 to allow regenerating configure on
more recent distributions.  autoconf 2.71 has been in Fedora since F36
and is the current version in Debian stable (bookworm).  It appears to
be current in Gentoo as well.

All sysdeps configure and preconfigure scripts have also been
regenerated; all changes are trivial transformations that do not affect
functionality.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-07-17 10:08:10 -04:00
Bert Wesarg
6cf4ebe10c manual: Fix typos in struct dl_find_object
Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-07-13 12:39:46 +02:00
Frédéric Bérat
64d9580cdf Allow glibc to be built with _FORTIFY_SOURCE
Add --enable-fortify-source option.

It is now possible to enable fortification through a configure option.
The level may be given as parameter, if none is provided, the configure
script will determine what is the highest level possible that can be set
considering GCC built-ins availability and set it.
If level is explicitly set to 3, configure checks if the compiler
supports the built-in function necessary for it or raise an error if it
isn't.

If the configure option isn't explicitly enabled, it _FORTIFY_SOURCE is
forcibly undefined (and therefore disabled).

The result of the configure checks are new variables, ${fortify_source}
and ${no_fortify_source} that can be used to appropriately populate
CFLAGS.

A dedicated patch will follow to make use of this variable in Makefiles
when necessary.

Updated NEWS and INSTALL.

Adding dedicated x86_64 variant that enables the configuration.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-07-05 16:59:34 +02:00
Florian Weimer
e18c293af0 manual: Update documentation of strerror and related functions
The current implementation of strerror is thread-safe, but this
has implications for the lifetime of the return string.

Describe the strerror_l function.  Describe both variants of the
strerror_r function.  Mention the lifetime of the returned string
for strerrorname_np and strerrordesc_np.  Clarify that perror
output depends on the current locale.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-07-03 12:36:56 +02:00
Florian Weimer
9651b06940 manual: Enhance documentation of the <ctype.h> functions
Describe the problems with signed characters, and the glibc extension
to deal with most of them.  Mention that the is* functions return
zero for the special argument EOF.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-07-03 12:36:56 +02:00
Paul Eggert
21fbc0a193 Call "CST" a time zone abbreviation, not a name
In documentation, call strings like "CST" time zone abbreviations, not
time zone names.  This terminology is more precise, and is what tzdb uses.
A string like "CST" is ambiguous and does not fully name a time zone.
2023-06-22 13:49:09 -07:00
Joseph Myers
2d88df5411 C2x scanf %b support
ISO C2x defines scanf %b for input of binary integers (with an
optional 0b or 0B prefix).  Implement such support, along with the
corresponding SCNb* macros in <inttypes.h>.  Unlike the support for
binary integers with 0b or 0B prefix with scanf %i, this is supported
in all versions of scanf (independent of the standards mode used for
compilation), because there are no backwards compatibility concerns
(%b wasn't previously a supported format) the way there were for %i.

Tested for x86_64 and x86.
2023-06-19 19:40:34 +00:00
Joseph Myers
5f83b2674e C2x printf %wN, %wfN support (bug 24466)
ISO C2x defines printf length modifiers wN (for intN_t / int_leastN_t
/ uintN_t / uint_leastN_t) and wfN (for int_fastN_t / uint_fastN_t).
Add support for those length modifiers (such a feature was previously
requested in bug 24466).  scanf support is to be added separately.
GCC 13 has format checking support for these modifiers.

When used with the support for registering format specifiers, these
modifiers are translated to existing flags in struct printf_info,
rather than trying to add some way of distinguishing them without
breaking the printf_info ABI.  C2x requires an error to be returned
for unsupported values of N; this is implemented for printf-family
functions, but the parse_printf_format interface doesn't support error
returns, so such an error gets discarded by that function.

Tested for x86_64 and x86.
2023-06-19 18:52:12 +00:00
Paul Eggert
d2fda60e7c manual: Manual update for strlcat, strlcpy, wcslcat, wclscpy
Co-authored-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-06-14 18:10:27 +02:00
Paul Pluzhnikov
64d9ebae87 Fix misspellings in manual/ -- BZ 25337 2023-05-27 16:41:44 +00:00
DJ Delorie
d1417176a3 aligned_alloc: conform to C17
This patch adds the strict checking for power-of-two alignments
in aligned_alloc(), and updates the manual accordingly.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-05-08 16:40:10 -04:00
Florian Weimer
2f679937b3 manual: Remove unsupported line breaks in waiting-with-clock section
The argument to @deftypefun must be on a single line.
Also add the missing @safety for sem_clockwait.

Reported-by: Nilgün Belma Bugüner <nillguine@gmail.com>
2023-05-08 13:14:22 +02:00
Florian Weimer
bf88b47ecb Revert "riscv: Resolve symbols directly for symbols with STO_RISCV_VARIANT_CC."
This reverts commit 117e8b341c.

Reason for revert: Causes elf/tst-glibcelf and elf/tst-relro-*
to fail on all architectures.
2023-05-07 14:16:03 +02:00
Joe Ramsay
cd94326a13 Enable libmvec support for AArch64
This patch enables libmvec on AArch64. The proposed change is mainly
implementing build infrastructure to add the new routines to ABI,
tests and benchmarks. I have demonstrated how this all fits together
by adding implementations for vector cos, in both single and double
precision, targeting both Advanced SIMD and SVE.

The implementations of the routines themselves are just loops over the
scalar routine from libm for now, as we are more concerned with
getting the plumbing right at this point. We plan to contribute vector
routines from the Arm Optimized Routines repo that are compliant with
requirements described in the libmvec wiki.

Building libmvec requires minimum GCC 10 for SVE ACLE. To avoid raising
the minimum GCC by such a big jump, we allow users to disable libmvec
if their compiler is too old.

Note that at this point users have to manually call the vector math
functions. This seems to be acceptable to some downstream users.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2023-05-03 12:09:49 +01:00
Hsiangkai Wang
117e8b341c
riscv: Resolve symbols directly for symbols with STO_RISCV_VARIANT_CC.
In some cases, we do not want to go through the resolver for function
calls. For example, functions with vector arguments will use vector
registers to pass arguments. In the resolver, we do not save/restore the
vector argument registers for lazy binding efficiency. To avoid ruining
the vector arguments, functions with vector arguments will not go
through the resolver.

To achieve the goal, we will annotate the function symbols with
STO_RISCV_VARIANT_CC flag and add DT_RISCV_VARIANT_CC tag in the dynamic
section. In the first pass on PLT relocations, we do not set up to call
_dl_runtime_resolve. Instead, we resolve the functions directly.

Signed-off-by: Hsiangkai Wang <kai.wang@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://inbox.sourceware.org/libc-alpha/20230314162512.35802-1-kito.cheng@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-28 07:02:42 -07:00
Gavin Smith
e91c7b53c4 manual: document posix_openpt (bug 17010)
State that getpt is similar to posix_openpt.  Use posix_openpt
instead of getpt in example.

Signed-off-by: Gavin Smith <gavinsmith0123@gmail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-04-26 12:29:39 +00:00
Cupertino Miranda
b630be0922 Created tunable to force small pages on stack allocation.
Created tunable glibc.pthread.stack_hugetlb to control when hugepages
can be used for stack allocation.
In case THP are enabled and glibc.pthread.stack_hugetlb is set to
0, glibc will madvise the kernel not to use allow hugepages for stack
allocations.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-04-20 13:54:24 -03:00
Paul Eggert
54ae6d81c9 manual: update AddressSanitizer discussion
* manual/string.texi (Truncating Strings): Update obsolescent
reference and use the more-generic term “AddressSanitizer”.
Mention fortification, too.  -fcheck-pointer-bounds is no longer
supported.
2023-04-08 13:53:28 -07:00
Paul Eggert
f173e27272 manual: document snprintf truncation better 2023-04-08 13:53:22 -07:00
Paul Eggert
1fb225923a manual: improve string section wording
* manual/string.texi: Editorial fixes.  Do not say “text” when
“string” or “string contents” is meant, as a C string can contain
bytes that are not valid text in the current encoding.
When warning about strcat efficiency, warn similarly about strncat
and wcscat.  “coping” → “copying”.
Mention at the start of the two problematic sections that problems
are discussed at section end.
2023-04-08 13:51:26 -07:00
Paul Eggert
a778333951 manual: fix texinfo typo
* manual/creature.texi (Feature Test Macros): Fix
“creature.texi:309: warning: `.' or `,' must follow @xref, not f”.
2023-04-08 13:51:26 -07:00
H.J. Lu
81a3cc956e <sys/platform/x86.h>: Add PREFETCHI support
Add PREFETCHI support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
b05521c916 <sys/platform/x86.h>: Add AMX-COMPLEX support
Add AMX-COMPLEX support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
609b7b2d3c <sys/platform/x86.h>: Add AVX-NE-CONVERT support
Add AVX-NE-CONVERT support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
4c120c88a6 <sys/platform/x86.h>: Add AVX-VNNI-INT8 support
Add AVX-VNNI-INT8 support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
b39741b45f <sys/platform/x86.h>: Add MSRLIST support
Add MSRLIST support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
96037c697d <sys/platform/x86.h>: Add AVX-IFMA support
Add AVX-IFMA support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
8b4cc05eab <sys/platform/x86.h>: Add AMX-FP16 support
Add AMX-FP16 support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
227983551d <sys/platform/x86.h>: Add WRMSRNS support
Add WRMSRNS support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
a00db8305d <sys/platform/x86.h>: Add ArchPerfmonExt support
Add Architectural Performance Monitoring Extended Leaf (EAX = 23H)
support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
2f02d0d8e1 <sys/platform/x86.h>: Add CMPCCXADD support
Add CMPCCXADD support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
aa528a579b <sys/platform/x86.h>: Add LASS support
Add Linear Address Space Separation (LASS) support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
231bf916ce <sys/platform/x86.h>: Add RAO-INT support
Add RAO-INT support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
fb90dc8513 <sys/platform/x86.h>: Add LBR support
Add architectural LBR support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
f47b7d96fb <sys/platform/x86.h>: Add RTM_FORCE_ABORT support
Add RTM_FORCE_ABORT support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
f6790a489d <sys/platform/x86.h>: Add SGX-KEYS support
Add SGX-KEYS support to <sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
09cc5fee21 <sys/platform/x86.h>: Add BUS_LOCK_DETECT support
Add Bus lock debug exceptions (BUS_LOCK_DETECT) support to
<sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
8c8e391166 <sys/platform/x86.h>: Add LA57 support
Add 57-bit linear addresses and five-level paging (LA57) support to
<sys/platform/x86.h>.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
H.J. Lu
083204a0e2 platform.texi: Move LAM after LAHF64_SAHF64
Move LAM after LAHF64_SAHF64 to sort x86 features.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
2023-04-05 14:46:10 -07:00
Siddhesh Poyarekar
ac2a14343e manual: Document __wur usage under _FORTIFY_SOURCE
The __warn_unused_result__ attribute is only enabled when fortification
is enabled.  Mention that in the document.  The rationale for this is
essentially to mitigate against CWE-252:

[1] https://cwe.mitre.org/data/definitions/252.html

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-04-03 10:20:04 -04:00
Adhemerval Zanella Netto
33237fe83d Remove --enable-tunables configure option
And make always supported.  The configure option was added on glibc 2.25
and some features require it (such as hwcap mask, huge pages support, and
lock elisition tuning).  It also simplifies the build permutations.

Changes from v1:
 * Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs
   more discussion.
 * Cleanup more code.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-03-29 14:33:06 -03:00
Adhemerval Zanella
6384171fa0 Remove --disable-experimental-malloc option
It is the default since 2.26 and it has bitrotten over the years,
By using it multiple malloc tests fails:

  FAIL: malloc/tst-memalign-2
  FAIL: malloc/tst-memalign-2-malloc-hugetlb1
  FAIL: malloc/tst-memalign-2-malloc-hugetlb2
  FAIL: malloc/tst-memalign-2-mcheck
  FAIL: malloc/tst-mxfast-malloc-hugetlb1
  FAIL: malloc/tst-mxfast-malloc-hugetlb2
  FAIL: malloc/tst-tcfree2
  FAIL: malloc/tst-tcfree2-malloc-hugetlb1
  FAIL: malloc/tst-tcfree2-malloc-hugetlb2

Checked on x86_64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>
2023-03-29 14:33:06 -03:00
Adhemerval Zanella Netto
91fc5b9990 Remove --with-default-link configure option
Now that there is no need to use a special linker script to hardening
internal data structures, remove the --with-default-link configure
option and associated definitions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-03-27 13:57:55 -03:00
Joseph Myers
2d4728e606 Update printf %b/%B C2x support
WG14 recently accepted two additions to the printf/scanf %b/%B
support: there are now PRIb* and SCNb* macros in <inttypes.h>, and
printf %B is now an optional feature defined in normative text,
instead of recommended practice, with corresponding PRIB* macros that
can also be used to test whether that optional feature is supported.
See N3072 items 14 and 15 for details (those changes were accepted,
some other changes in that paper weren't).

Add the corresponding PRI* macros to glibc and update one place in the
manual referring to %B as recommended.  (SCNb* should naturally be
added at the same time as the corresponding scanf %b support.)

Tested for x86_64 and x86.
2023-03-14 16:58:35 +00:00
Joseph Myers
dee2bea048 C2x scanf binary constant handling
C2x adds binary integer constants starting with 0b or 0B, and supports
those constants for the %i scanf format (in addition to the %b format,
which isn't yet implemented for scanf in glibc).  Implement that scanf
support for glibc.

As with the strtol support, this is incompatible with previous C
standard versions, in that such an input string starting with 0b or 0B
was previously required to be parsed as 0 (with the rest of the input
potentially matching subsequent parts of the scanf format string).
Thus this patch adds 12 new __isoc23_* functions per long double
format (12, 24 or 36 depending on how many long double formats the
glibc configuration supports), with appropriate header redirection
support (generally very closely following that for the __isoc99_*
scanf functions - note that __GLIBC_USE (DEPRECATED_SCANF) takes
precedence over __GLIBC_USE (C2X_STRTOL), so the case of GNU
extensions to C89 continues to get old-style GNU %a and does not get
this new feature).  The function names would remain as __isoc23_* even
if C2x ends up published in 2024 rather than 2023.

When scanf %b support is added, I think it will be appropriate for all
versions of scanf to follow C2x rules for inputs to the %b format
(given that there are no compatibility concerns for a new format).

Tested for x86_64 (full glibc testsuite).  The first version was also
tested for powerpc (32-bit) and powerpc64le (stdio-common/ and wcsmbs/
tests), and with build-many-glibcs.py.
2023-03-02 19:10:37 +00:00
H.J. Lu
188ecdb777 tunables.texi: Change \code{1} to @code{1}
Update

317f1c0a8a x86-64: Add glibc.cpu.prefer_map_32bit_exec [BZ #28656]
2023-02-23 08:50:19 -08:00
H.J. Lu
317f1c0a8a x86-64: Add glibc.cpu.prefer_map_32bit_exec [BZ #28656]
Crossing 2GB boundaries with indirect calls and jumps can use more
branch prediction resources on Intel Golden Cove CPU (see the
"Misprediction for Branches >2GB" section in Intel 64 and IA-32
Architectures Optimization Reference Manual.)  There is visible
performance improvement on workloads with many PLT calls when executable
and shared libraries are mmapped below 2GB.  Add the Prefer_MAP_32BIT_EXEC
bit so that mmap will try to map executable or denywrite pages in shared
libraries with MAP_32BIT first.

NB: Prefer_MAP_32BIT_EXEC reduces bits available for address space
layout randomization (ASLR), which is always disabled for SUID programs
and can only be enabled by the tunable, glibc.cpu.prefer_map_32bit_exec,
or the environment variable, LD_PREFER_MAP_32BIT_EXEC.  This works only
between shared libraries or between shared libraries and executables with
addresses below 2GB.  PIEs are usually loaded at a random address above
4GB by the kernel.
2023-02-22 18:28:37 -08:00
Simon Kissane
31be941e43 gmon: improve mcount overflow handling [BZ# 27576]
When mcount overflows, no gmon.out file is generated, but no message is printed
to the user, leaving the user with no idea why, and thinking maybe there is
some bug - which is how BZ 27576 ended up being logged. Print a message to
stderr in this case so the user knows what is going on.

As a comment in sys/gmon.h acknowledges, the hardcoded MAXARCS value is too
small for some large applications, including the test case in that BZ. Rather
than increase it, add tunables to enable MINARCS and MAXARCS to be overridden
at runtime (glibc.gmon.minarcs and glibc.gmon.maxarcs). So if a user gets the
mcount overflow error, they can try increasing maxarcs (they might need to
increase minarcs too if the heuristic is wrong in their case.)

Note setting minarcs/maxarcs too large can cause monstartup to fail with an
out of memory error. If you set them large enough, it can cause an integer
overflow in calculating the buffer size. I haven't done anything to defend
against that - it would not generally be a security vulnerability, since these
tunables will be ignored in suid/sgid programs (due to the SXID_ERASE default),
and if you can set GLIBC_TUNABLES in the environment of a process, you can take
it over anyway (LD_PRELOAD, LD_LIBRARY_PATH, etc). I thought about modifying
the code of monstartup to defend against integer overflows, but doing so is
complicated, and I realise the existing code is susceptible to them even prior
to this change (e.g. try passing a pathologically large highpc argument to
monstartup), so I decided just to leave that possibility in-place.

Add a test case which demonstrates mcount overflow and the tunables.

Document the new tunables in the manual.

Signed-off-by: Simon Kissane <skissane@gmail.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
2023-02-22 21:00:14 -05:00
Joseph Myers
64924422a9 C2x strtol binary constant handling
C2x adds binary integer constants starting with 0b or 0B, and supports
those constants in strtol-family functions when the base passed is 0
or 2.  Implement that strtol support for glibc.

As discussed at
<https://sourceware.org/pipermail/libc-alpha/2020-December/120414.html>,
this is incompatible with previous C standard versions, in that such
an input string starting with 0b or 0B was previously required to be
parsed as 0 (with the rest of the string unprocessed).  Thus, as
proposed there, this patch adds 20 new __isoc23_* functions with
appropriate header redirection support.  This patch does *not* do
anything about scanf %i (which will need 12 new functions per long
double variant, so 12, 24 or 36 depending on the glibc configuration),
instead leaving that for a future patch.  The function names would
remain as __isoc23_* even if C2x ends up published in 2024 rather than
2023.

Making this change leads to the question of what should happen to
internal uses of these functions in glibc and its tests.  The header
redirection (which applies for _GNU_SOURCE or any other feature test
macros enabling C2x features) has the effect of redirecting internal
uses but without those uses then ending up at a hidden alias (see the
comment in include/stdio.h about interaction with libc_hidden_proto).
It seems desirable for the default for internal uses to be the same
versions used by normal code using _GNU_SOURCE, so rather than doing
anything to disable that redirection, similar macro definitions to
those in include/stdio.h are added to the include/ headers for the new
functions.

Given that the default for uses in glibc is for the redirections to
apply, the next question is whether the C2x semantics are correct for
all those uses.  Uses with the base fixed to 10, 16 or any other value
other than 0 or 2 can be ignored.  I think this leaves the following
internal uses to consider (an important consideration for review of
this patch will be both whether this list is complete and whether my
conclusions on all entries in it are correct):

benchtests/bench-malloc-simple.c
benchtests/bench-string.h
elf/sotruss-lib.c
math/libm-test-support.c
nptl/perf.c
nscd/nscd_conf.c
nss/nss_files/files-parse.c
posix/tst-fnmatch.c
posix/wordexp.c
resolv/inet_addr.c
rt/tst-mqueue7.c
soft-fp/testit.c
stdlib/fmtmsg.c
support/support_test_main.c
support/test-container.c
sysdeps/pthread/tst-mutex10.c

I think all of these places are OK with the new semantics, except for
resolv/inet_addr.c, where the POSIX semantics of inet_addr do not
allow for binary constants; thus, I changed that file (to use
__strtoul_internal, whose semantics are unchanged) and added a test
for this case.  In the case of posix/wordexp.c I think accepting
binary constants is OK since POSIX explicitly allows additional forms
of shell arithmetic expressions, and in stdlib/fmtmsg.c SEV_LEVEL is
not in POSIX so again I think accepting binary constants is OK.

Functions such as __strtol_internal, which are only exported for
compatibility with old binaries from when those were used in inline
functions in headers, have unchanged semantics; the __*_l_internal
versions (purely internal to libc and not exported) have a new
argument to specify whether to accept binary constants.

As well as for the standard functions, the header redirection also
applies to the *_l versions (GNU extensions), and to legacy functions
such as strtoq, to avoid confusing inconsistency (the *q functions
redirect to __isoc23_*ll rather than needing their own __isoc23_*
entry points).  For the functions that are only declared with
_GNU_SOURCE, this means the old versions are no longer available for
normal user programs at all.  An internal __GLIBC_USE_C2X_STRTOL macro
is used to control the redirections in the headers, and cases in glibc
that wish to avoid the redirections - the function implementations
themselves and the tests of the old versions of the GNU functions -
then undefine and redefine that macro to allow the old versions to be
accessed.  (There would of course be greater complexity should we wish
to make any of the old versions into compat symbols / avoid them being
defined at all for new glibc ABIs.)

strtol_l.c has some similarity to strtol.c in gnulib, but has already
diverged some way (and isn't listed at all at
https://sourceware.org/glibc/wiki/SharedSourceFiles unlike strtoll.c
and strtoul.c); I haven't made any attempts at gnulib compatibility in
the changes to that file.

I note incidentally that inttypes.h and wchar.h are missing the
__nonnull present on declarations of this family of functions in
stdlib.h; I didn't make any changes in that regard for the new
declarations added.
2023-02-16 23:02:40 +00:00
Stefan Liebler
41f67ccbe9 S390: Influence hwcaps/stfle via GLIBC_TUNABLES.
This patch enables the option to influence hwcaps and stfle bits used
by the s390 specific ifunc-resolvers.  The currently x86-specific
tunable glibc.cpu.hwcaps is also used on s390x to achieve the task. In
addition the user can also set a CPU arch-level like z13 instead of
single HWCAP and STFLE features.

Note that the tunable only handles the features which are really used
in the IFUNC-resolvers.  All others are ignored as the values are only
used inside glibc.  Thus we can influence:
- HWCAP_S390_VXRS (z13)
- HWCAP_S390_VXRS_EXT (z14)
- HWCAP_S390_VXRS_EXT2 (z15)
- STFLE_MIE3 (z15)

The influenced hwcap/stfle-bits are stored in the s390-specific
cpu_features struct which also contains reserved fields for future
usage.

The ifunc-resolvers and users of stfle bits are adjusted to use the
information from cpu_features struct.

On 31bit, the ELF_MACHINE_IRELATIVE macro is now also defined.
Otherwise the new ifunc-resolvers segfaults as they depend on
the not yet processed_rtld_global_ro@GLIBC_PRIVATE relocation.
2023-02-07 09:19:27 +01:00
Wilco Dijkstra
32c7acd464 Replace rawmemchr (s, '\0') with strchr
Almost all uses of rawmemchr find the end of a string.  Since most targets use
a generic implementation, replacing it with strchr is better since that is
optimized by compilers into strlen (s) + s.  Also fix the generic rawmemchr
implementation to use a cast to unsigned char in the if statement.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2023-02-06 16:16:19 +00:00