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* Implement C23 <stdbit.h>Joseph Myers2024-01-031-0/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* Add the wcslcpy, wcslcat functionsFlorian Weimer2023-06-141-0/+4
| | | | | | | These functions are about to be added to POSIX, under Austin Group issue 986. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* Implement strlcpy and strlcat [BZ #178]Florian Weimer2023-06-141-0/+4
| | | | | | | | | | | These functions are about to be added to POSIX, under Austin Group issue 986. The fortified strlcat implementation does not raise SIGABRT if the destination buffer does not contain a null terminator, it just inherits the non-failing regular strlcat behavior. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* htl: move pthread_self info libc.Guy-Fleury Iteriteka2023-04-051-0/+2
| | | | | Signed-off-by: Guy-Fleury Iteriteka <gfleury@disroot.org> Message-Id: <20230318095826.1125734-4-gfleury@disroot.org>
* hurd: Remove __hurd_threadvar_stack_{offset,mask}Sergey Bugaev2023-04-031-2/+0
| | | | | | | | | | | Noone is or should be using __hurd_threadvar_stack_{offset,mask}, we have proper TLS now. These two remaining variables are never set to anything other than zero, so any code that would try to use them as described would just dereference a zero pointer and crash. So remove them entirely. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> Message-Id: <20230319151017.531737-6-bugaevc@gmail.com>
* C2x scanf binary constant handlingJoseph Myers2023-03-021-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* C2x strtol binary constant handlingJoseph Myers2023-02-161-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* stdlib: Add arc4random, arc4random_buf, and arc4random_uniform (BZ #4417)Adhemerval Zanella Netto2022-07-221-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The implementation is based on scalar Chacha20 with per-thread cache. It uses getrandom or /dev/urandom as fallback to get the initial entropy, and reseeds the internal state on every 16MB of consumed buffer. To improve performance and lower memory consumption the per-thread cache is allocated lazily on first arc4random functions call, and if the memory allocation fails getentropy or /dev/urandom is used as fallback. The cache is also cleared on thread exit iff it was initialized (so if arc4random is not called it is not touched). Although it is lock-free, arc4random is still not async-signal-safe (the per thread state is not updated atomically). The ChaCha20 implementation is based on RFC8439 [1], omitting the final XOR of the keystream with the plaintext because the plaintext is a stream of zeros. This strategy is similar to what OpenBSD arc4random does. The arc4random_uniform is based on previous work by Florian Weimer, where the algorithm is based on Jérémie Lumbroso paper Optimal Discrete Uniform Generation from Coin Flips, and Applications (2013) [2], who credits Donald E. Knuth and Andrew C. Yao, The complexity of nonuniform random number generation (1976), for solving the general case. The main advantage of this method is the that the unit of randomness is not the uniform random variable (uint32_t), but a random bit. It optimizes the internal buffer sampling by initially consuming a 32-bit random variable and then sampling byte per byte. Depending of the upper bound requested, it might lead to better CPU utilization. Checked on x86_64-linux-gnu, aarch64-linux, and powerpc64le-linux-gnu. Co-authored-by: Florian Weimer <fweimer@redhat.com> Reviewed-by: Yann Droneaud <ydroneaud@opteya.com> [1] https://datatracker.ietf.org/doc/html/rfc8439 [2] https://arxiv.org/pdf/1304.1916.pdf
* stdlib: Implement mbrtoc8, c8rtomb, and the char8_t typedef.Tom Honermann2022-07-061-0/+2
| | | | | | | | | | | | | | | | | This change provides implementations for the mbrtoc8 and c8rtomb functions adopted for C++20 via WG21 P0482R6 and for C2X via WG14 N2653. It also provides the char8_t typedef from WG14 N2653. The mbrtoc8 and c8rtomb functions are declared in uchar.h in C2X mode or when the _GNU_SOURCE macro or C++20 __cpp_char8_t feature test macro is defined. The char8_t typedef is declared in uchar.h in C2X mode or when the _GNU_SOURCE macro is defined and the C++20 __cpp_char8_t feature test macro is not defined (if __cpp_char8_t is defined, then char8_t is a builtin type). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* posix: Replace posix_spawnattr_tc{get,set}pgrp_np with ↵Adhemerval Zanella2022-02-021-2/+1
| | | | | | | | | | | | | | | | | | posix_spawn_file_actions_addtcsetpgrp_np The posix_spawnattr_tcsetpgrp_np works on a file descriptor (the controlling terminal), so it would make more sense to actually fit it on the file actions API. Also, POSIX_SPAWN_TCSETPGROUP is not really required since it is implicit by the presence of tcsetpgrp file action. The posix/tst-spawn6.c is also fixed when TTY can is not present. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* hurd: Add posix_spawnattr_tc{get,set}pgrp_np on libc.abilistAdhemerval Zanella2022-01-261-0/+2
| | | | Commit 342cc934a3bf74ac missed the update-abi for the ABI.
* elf: Add _dl_find_object functionFlorian Weimer2021-12-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | It can be used to speed up the libgcc unwinder, and the internal _dl_find_dso_for_object function (which is used for caller identification in dlopen and related functions, and in dladdr). _dl_find_object is in the internal namespace due to bug 28503. If libgcc switches to _dl_find_object, this namespace issue will be fixed. It is located in libc for two reasons: it is necessary to forward the call to the static libc after static dlopen, and there is a link ordering issue with -static-libgcc and libgcc_eh.a because libc.so is not a linker script that includes ld.so in the glibc build tree (so that GCC's internal -lc after libgcc_eh.a does not pick up ld.so). It is necessary to do the i386 customization in the sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because otherwise, multilib installations are broken. The implementation uses software transactional memory, as suggested by Torvald Riegel. Two copies of the supporting data structures are used, also achieving full async-signal-safety. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* hurd: Implement close_range and closefromSergey Bugaev2021-11-071-0/+1
| | | | | | | | | | | | | | | | | | The close_range () function implements the same API as the Linux and FreeBSD syscalls. It operates atomically and reliably. The specified upper bound is clamped to the actual size of the file descriptor table; it is expected that the most common use case is with last = UINT_MAX. Like in the Linux syscall, it is also possible to pass the CLOSE_RANGE_CLOEXEC flag to mark the file descriptors in the range cloexec instead of acually closing them. Also, add a Hurd version of the closefrom () function. Since unlike on Linux, close_range () cannot fail due to being unuspported by the running kernel, a fallback implementation is never necessary. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> Message-Id: <20211106153524.82700-1-bugaevc@gmail.com>
* String: Add support for __memcmpeq() ABI on all targetsNoah Goldstein2021-10-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | No bug. This commit adds support for __memcmpeq() as a new ABI for all targets. In this commit __memcmpeq() is implemented only as an alias to the corresponding targets memcmp() implementation. __memcmpeq() is added as a new symbol starting with GLIBC_2.35 and defined in string.h with comments explaining its behavior. Basic tests that it is callable and works where added in string/tester.c As discussed in the proposal "Add new ABI '__memcmpeq()' to libc" __memcmpeq() is essentially a reserved namespace for bcmp(). The means is shares the same specifications as memcmp() except the return value for non-equal byte sequences is any non-zero value. This is less strict than memcmp()'s return value specification and can be better optimized when a boolean return is all that is needed. __memcmpeq() is meant to only be called by compilers if they can prove that the return value of a memcmp() call is only used for its boolean value. All tests in string/tester.c passed. As well build succeeds on x86_64-linux-gnu target.
* Move malloc_{g,s}et_state to libc_malloc_debugSiddhesh Poyarekar2021-07-221-2/+0
| | | | | | | | | | | | | | | | | | | | | | | These deprecated functions are only safe to call from __malloc_initialize_hook and as a result, are not useful in the general case. Move the implementations to libc_malloc_debug so that existing binaries that need it will now have to preload the debug DSO to work correctly. This also allows simplification of the core malloc implementation by dropping all the undumping support code that was added to make malloc_set_state work. One known breakage is that of ancient emacs binaries that depend on this. They will now crash when running with this libc. With LD_BIND_NOW=1, it will terminate immediately because of not being able to find malloc_set_state but with lazy binding it will crash in unpredictable ways. It will need a preloaded libc_malloc_debug.so so that its initialization hook is executed to allow its malloc implementation to work properly. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move res_query functions into libcFlorian Weimer2021-07-191-0/+12
| | | | | | | | | | | | | | | This switches to public symbols without __ prefixes, due to improved namespace management in glibc. The script was used with --no-new-version to move the symbols __res_nquery, __res_nquerydomain, __res_nsearch, __res_query, __res_querydomain, __res_search, res_query, res_querydomain, res_search. The public symbols res_nquery, res_nquerydomain, res_nsearch, res_ownok, res_query, res_querydomain, res_search were added with make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move res_mkquery, res_nmkquery into libcFlorian Weimer2021-07-191-0/+4
| | | | | | | | | | | | | This switches to public symbols without __ prefixes, due to improved namespace management in glibc. The symbols res_mkquery, __res_mkquery, __res_nmkquery were moved with the script (using --no-new-version). res_mkquery@@GLIBC_2.34, res_nmkquery@@GLIBC_2.34 were added using make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move res_send, res_nsend into libcFlorian Weimer2021-07-191-0/+4
| | | | | | | | | | | Switch to public symbols without __ prefix (due to improved namespace management). __res_send, __res_nsend were moved using the script (with --no-new-version). res_send@@GLIBC_2.34 and res_nsend@@GLIBC_2.34 were added using make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Rename res_comp.c to res-name-checking.c and move into libcFlorian Weimer2021-07-191-0/+8
| | | | | | | | | | | | | | | This reflects what the remaining functions in the file do. The __res_dnok, __res_hnok, __res_mailok, __res_ownok were moved with the script, using --no-new-version, and turned into compat symbols. __libc_res_dnok@@GLIBC_PRIVATE and __libc_res_hnok@@GLIBC_PRIVATE are added for internal use, to avoid accidentally binding to compatibility symbols. The new public symbols res_dnok, res_hnok, res_mailok, res_ownok were added using make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move dn_skipname to its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | | | | | | | And reformat it to GNU style. dn_skipname is used outside glibc, so do not deprecate it, and export it as dn_skipname (not __dn_skipname). Due to internal users, provide a __libc_dn_skipname alias, and keep __dn_skipname as a pure compatibility symbol. __dn_skipname@GLIBC_2.0 was moved using the script, and dn_skipname@@GLIBC_2.34 was added using make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move dn_comp to its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | | | | | | | And reformat it to GNU style. dn_comp is used in various programs, so keep it as a non-deprecated symbol. Switch to dn_comp (not __dn_comp) for the ABI name. There are no internal users, so interposition is not a problem. The __dn_comp symbol was moved with scripts/move-symbol-to-libc.py --no-new-version. dn_comp@@GLIBC_2.34 was added with make update-all-abi. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move dn_expand to its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | | | | | | | | | | And reformat to GNU style. This switches back to the dn_expand name for the ABI symbol and turns __dn_expand into a compatibility symbol. With the improved namespace management in current glibc, it is no longer necessary to use a private namespace symbol. To avoid old code binding to a GLIBC_PRIVATE symbol by accident, use __libc_dn_expand for the internal symbol name. The symbols dn_expand, __dnexpand were moved using scripts/move-symbol-to-libc.py, followed by an adjustment to make dn_expand the only GLIBC_2.34 symbol. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_compress into its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | And reformat to GNU style. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_pack into its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | And reformat to GNU style, and eliminate the labellen function. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_pton into its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | And reformat to GNU style, and eliminate the digits variable. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_uncompress into its own file and into libcFlorian Weimer2021-07-191-0/+2
| | | | | | | | | | And reformat to GNU style. Check for negative error returns (instead of -1). The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_skip to its own file and into libc (bug 28091)Florian Weimer2021-07-191-0/+2
| | | | | | | | | | And reformat to GNU style. Avoid out-of-bounds pointer arithmetic. This also results in a fix of bug 28091 due to the additional packet length checks. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@systemhalted.org>
* resolv: Move ns_name_unpack to its own file and into libcFlorian Weimer2021-07-151-0/+2
| | | | | | | | | | Reformat to GNU style. Avoid out-of-bounds buffer arithmetic. Eliminate the labellen function. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* resolv: Move ns_name_ntop to its own file and into libcFlorian Weimer2021-07-151-0/+2
| | | | | | | | | | | | Reformat to GNU style. Avoid out-of-bounds pointer arithmetic (e.g., use eom - dn < 2 instead of dn + 1 >= eom). Inline the labellen function and fold the compression pointer check into the length check (l >= 64). Assume ASCII encoding. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* posix: Add posix_spawn_file_actions_addclosefrom_npAdhemerval Zanella2021-07-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a way to close a range of file descriptors on posix_spawn as a new file action. The API is similar to the one provided by Solaris 11 [1], where the file action causes the all open file descriptors greater than or equal to input on to be closed when the new process is spawned. The function posix_spawn_file_actions_addclosefrom_np is safe to be implemented by iterating over /proc/self/fd, since the Linux spawni.c helper process does not use CLONE_FILES, so its has own file descriptor table and any failure (in /proc operation) aborts the process creation and returns an error to the caller. I am aware that this file action might be redundant to the current approach of POSIX in promoting O_CLOEXEC in more interfaces. However O_CLOEXEC is still not the default and for some specific usages, the caller needs to close all possible file descriptors to avoid them leaking. Some examples are CPython (discussed in BZ#10353) and OpenJDK jspawnhelper [2] (where OpenJDK spawns a helper process to exactly closes all file descriptors). Most likely any environment which calls functions that might open file descriptor under the hood and aim to use posix_spawn might face the same requirement. Checked on x86_64-linux-gnu and i686-linux-gnu on kernel 5.11 and 4.15. [1] https://docs.oracle.com/cd/E36784_01/html/E36874/posix-spawn-file-actions-addclosefrom-np-3c.html [2] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82
* io: Add closefrom [BZ #10353]Adhemerval Zanella2021-07-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function closes all open file descriptors greater than or equal to input argument. Negative values are clamped to 0, i.e, it will close all file descriptors. As indicated by the bug report, this is a common symbol provided by different systems (Solaris, OpenBSD, NetBSD, FreeBSD) and, although its has inherent issues with not taking in consideration internal libc file descriptors (such as syslog), this is also a common feature used in multiple projects [1][2][3][4][5]. The Linux fallback implementation iterates over /proc and close all file descriptors sequentially. Although it was raised the questioning whether getdents on /proc/self/fd might return disjointed entries when file descriptor are closed; it does not seems the case on my testing on multiple kernel (v4.18, v5.4, v5.9) and the same strategy is used on different projects [1][2][3][5]. Also, the interface is set a fail-safe meaning that a failure in the fallback results in a process abort. Checked on x86_64-linux-gnu and i686-linux-gnu on kernel 5.11 and 4.15. [1] https://github.com/systemd/systemd/blob/5238e9575906297608ff802a27e2ff9effa3b338/src/basic/fd-util.c#L217 [2] https://github.com/lxc/lxc/blob/ddf4b77e11a4d08f09b7b9cd13e593f8c047edc5/src/lxc/start.c#L236 [3] https://github.com/python/cpython/blob/9e4f2f3a6b8ee995c365e86d976937c141d867f8/Modules/_posixsubprocess.c#L220 [4] https://github.com/rust-lang/rust/blob/5f47c0613ed4eb46fca3633c1297364c09e5e451/src/libstd/sys/unix/process2.rs#L303-L308 [5] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82
* login: Move libutil into libcFlorian Weimer2021-06-301-0/+12
| | | | | | | | | | | | | | | | The symbols forkpty, login, login_tty, logout, logwtmp, openpty were moved using scripts/move-symbol-to-libc.py. This is a single commit because most of the symbols are tied together via forkpty, for example. Several changes to use hidden prototypes are needed. This commit also updates pseudoterminal terminology on modified lines. For 390 (31-bit), this commit follows the existing style for the compat symbol version creation. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* posix: Add _Fork [BZ #4737]Adhemerval Zanella2021-06-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Austin Group issue 62 [1] dropped the async-signal-safe requirement for fork and provided a async-signal-safe _Fork replacement that does not run the atfork handlers. It will be included in the next POSIX standard. It allow to close a long standing issue to make fork AS-safe (BZ#4737). As indicated on the bug, besides the internal lock for the atfork handlers itself; there is no guarantee that the handlers itself will not introduce more AS-safe issues. The idea is synchronize fork with the required internal locks to allow children in multithread processes to use mostly of standard function (even though POSIX states only AS-safe function should be used). On signal handles, _Fork should be used intead and only AS-safe functions should be used. For testing, the new tst-_Fork only check basic usage. I also added a new tst-mallocfork3 which uses the same strategy to check for deadlock of tst-mallocfork2 but using threads instead of subprocesses (and it does deadlock if it replaces _Fork with fork). [1] https://austingroupbugs.net/view.php?id=62
* rt: Move shm_unlink into libcFlorian Weimer2021-06-211-0/+2
| | | | | | | | | This function has no dependency on libpthread, so the move is also applied to Hurd. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* rt: Move shm_open into libcFlorian Weimer2021-06-211-0/+2
| | | | | | | | | | | | This function has no dependency on libpthread, so the move is also applied to Hurd. To avoid localplt failures, use __open64_nocancel instead of pthread_setcancelstate and open. The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlopen into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlvsym into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlinfo into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dladdr1 into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlmopen into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlsym into libcFlorian Weimer2021-06-031-0/+2
| | | | | | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. In elf/Makefile, remove the $(libdl) dependency from testobj1.so because it the unused libdl DSO now causes elf/tst-unused-deps to fail. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dladdr into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlclose into libcFlorian Weimer2021-06-031-0/+2
| | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dlfcn: Move dlerror into libcFlorian Weimer2021-06-021-0/+2
| | | | | | | | | | | | | | The symbol was moved using scripts/move-symbol-to-libc.py. There is a minor functionality enhancement: dlerror now sets errno if it was set as part of the exception. (This is the result of using %m in asprintf, to avoid the strerror PLT call.) The previous errno value upon function return was unpredictable. Documenting this as a feature is premature; we need to make sure that the error codes are meaningful when they are set by the dynamic loader. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Add C2X timespec_getresJoseph Myers2021-05-171-0/+1
| | | | | | | | | | | | | | | | | | | ISO C2X adds a timespec_getres function alongside the C11 timespec_get, with functionality similar to that of POSIX clock_getres (including allowing a NULL pointer to be passed to the function). Implement this function for glibc, similarly to the implementation of timespec_get. This includes a basic test like that of timespec_get, but no documentation in the manual, given that TIME_UTC and timespec_get aren't documented in the manual at all. The handling of 64-bit time follows that in timespec_get; people maintaining patch series for 64-bit time will need to update them accordingly (to export __timespec_getres64, redirect calls in time.h and run the test for _TIME_BITS=64). Tested for x86_64 and x86, and (previous version; only testcase differs) with build-many-glibcs.py.
* linux: Add execveat system call wrapperAlexandra Hájková2021-05-031-0/+1
| | | | | | | | | | | It operates similar to execve and it is is already used to implement fexecve without requiring /proc to be mounted. However, different than fexecve, if the syscall is not supported by the kernel an error is returned instead of trying a fallback. Checked on x86_64-linux-gnu and powerpc64le-linux-gnu. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* hurd: Export _hurd_libc_proc_initSamuel Thibault2021-04-121-0/+1
| | | | | hurd's libdiskfs needs to be able to call _hurd_init + _hurd_libc_proc_init for bootstrap initialization.
* Move __isnanf128 to libc.soSiddhesh Poyarekar2021-03-301-0/+2
| | | | | | | | All of the isnan functions are in libc.so due to printf_fp, so move __isnanf128 there too for consistency. Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@ascii.art.br> Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Reduce the statically linked startup code [BZ #23323]Florian Weimer2021-02-251-0/+1
| | | | | | | | | | | | | | | | | | | It turns out the startup code in csu/elf-init.c has a perfect pair of ROP gadgets (see Marco-Gisbert and Ripoll-Ripoll, "return-to-csu: A New Method to Bypass 64-bit Linux ASLR"). These functions are not needed in dynamically-linked binaries because DT_INIT/DT_INIT_ARRAY are already processed by the dynamic linker. However, the dynamic linker skipped the main program for some reason. For maximum backwards compatibility, this is not changed, and instead, the main map is consulted from __libc_start_main if the init function argument is a NULL pointer. For statically linked binaries, the old approach based on linker symbols is still used because there is nothing else available. A new symbol version __libc_start_main@@GLIBC_2.34 is introduced because new binaries running on an old libc would not run their ELF constructors, leading to difficult-to-debug issues.
* <sys/platform/x86.h>: Remove the C preprocessor magicH.J. Lu2021-01-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In <sys/platform/x86.h>, define CPU features as enum instead of using the C preprocessor magic to make it easier to wrap this functionality in other languages. Move the C preprocessor magic to internal header for better GCC codegen when more than one features are checked in a single expression as in x86-64 dl-hwcaps-subdirs.c. 1. Rename COMMON_CPUID_INDEX_XXX to CPUID_INDEX_XXX. 2. Move CPUID_INDEX_MAX to sysdeps/x86/include/cpu-features.h. 3. Remove struct cpu_features and __x86_get_cpu_features from <sys/platform/x86.h>. 4. Add __x86_get_cpuid_feature_leaf to <sys/platform/x86.h> and put it in libc. 5. Make __get_cpu_features() private to glibc. 6. Replace __x86_get_cpu_features(N) with __get_cpu_features(). 7. Add _dl_x86_get_cpu_features to GLIBC_PRIVATE. 8. Use a single enum index for each CPU feature detection. 9. Pass the CPUID feature leaf to __x86_get_cpuid_feature_leaf. 10. Return zero struct cpuid_feature for the older glibc binary with a smaller CPUID_INDEX_MAX [BZ #27104]. 11. Inside glibc, use the C preprocessor magic so that cpu_features data can be loaded just once leading to more compact code for glibc. 256 bits are used for each CPUID leaf. Some leaves only contain a few features. We can add exceptions to such leaves. But it will increase code sizes and it is harder to provide backward/forward compatibilities when new features are added to such leaves in the future. When new leaves are added, _rtld_global_ro offsets will change which leads to race condition during in-place updates. We may avoid in-place updates by 1. Rename the old glibc. 2. Install the new glibc. 3. Remove the old glibc. NB: A function, __x86_get_cpuid_feature_leaf , is used to avoid the copy relocation issue with IFUNC resolver as shown in IFUNC resolver tests.
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-07-03 15:25:21 +0000