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2024-01-22sparc64: Remove unwind information from signal return stubs [BZ#31244]Adhemerval Zanella
Similar to sparc32 fix, remove the unwind information on the signal return stubs. This fixes the regressions: FAIL: nptl/tst-cancel24-static FAIL: nptl/tst-cond8-static FAIL: nptl/tst-mutex8-static FAIL: nptl/tst-mutexpi8-static FAIL: nptl/tst-mutexpi9 On sparc64-linux-gnu.
2024-01-18sparc: Remove unwind information from signal return stubs [BZ #31244]Daniel Cederman
The functions were previously written in C, but were not compiled with unwind information. The ENTRY/END macros includes .cfi_startproc and .cfi_endproc which adds unwind information. This caused the tests cleanup-8 and cleanup-10 in the GCC testsuite to fail. This patch adds a version of the ENTRY/END macros without the CFI instructions that can be used instead. sigaction registers a restorer address that is located two instructions before the stub function. This patch adds a two instruction padding to avoid that the unwinder accesses the unwind information from the function that the linker has placed right before it in memory. This fixes an issue with pthread_cancel that caused tst-mutex8-static (and other tests) to fail. Signed-off-by: Daniel Cederman <cederman@gaisler.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-01-17Update syscall lists for Linux 6.7Joseph Myers
Linux 6.7 adds the futex_requeue, futex_wait and futex_wake syscalls, and enables map_shadow_stack for architectures previously missing it. Update syscall-names.list and regenerate the arch-syscall.h headers with build-many-glibcs.py update-syscalls. Tested with build-many-glibcs.py.
2024-01-12math: remove exp10 wrappersWilco Dijkstra
Remove the error handling wrapper from exp10. This is very similar to the changes done to exp and exp2, except that we also need to handle pow10 and pow10l. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-01-03Implement C23 <stdbit.h>Joseph Myers
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.
2024-01-01Update copyright dates with scripts/update-copyrightsPaul Eggert
2023-11-03Update syscall lists for Linux 6.6Adhemerval Zanella
Linux 6.6 has one new syscall for all architectures, fchmodat2, and the map_shadow_stack on x86_64.
2023-10-30crypt: Remove libcrypt supportAdhemerval Zanella
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>
2023-09-12Update syscall lists for Linux 6.5Joseph Myers
Linux 6.5 has one new syscall, cachestat, and also enables the cacheflush syscall for hppa. Update syscall-names.list and regenerate the arch-syscall.h headers with build-many-glibcs.py update-syscalls. Tested with build-many-glibcs.py.
2023-09-05linux: Add pidfd_getpidAdhemerval Zanella Netto
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>
2023-09-05posix: Add pidfd_spawn and pidfd_spawnp (BZ 30349)Adhemerval Zanella Netto
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>
2023-09-05linux: Add posix_spawnattr_{get, set}cgroup_np (BZ 26371)Adhemerval Zanella Netto
These functions allow to posix_spawn and posix_spawnp to use CLONE_INTO_CGROUP with clone3, allowing the child process to be created in a different cgroup version 2. These are GNU extensions that are available only for Linux, and also only for the architectures that implement clone3 wrapper (HAVE_CLONE3_WRAPPER). To create a process on a different cgroupv2, one can use the: posix_spawnattr_t attr; posix_spawnattr_init (&attr); posix_spawnattr_setflags (&attr, POSIX_SPAWN_SETCGROUP); posix_spawnattr_setcgroup_np (&attr, cgroup); posix_spawn (...) Similar to other posix_spawn flags, POSIX_SPAWN_SETCGROUP control whether the cgroup file descriptor will be used or not with clone3. There is no fallback if either clone3 does not support the flag or if the architecture does not provide the clone3 wrapper, in this case posix_spawn returns EOPNOTSUPP. Checked on x86_64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-09-05linux: Define __ASSUME_CLONE3 to 0 for alpha, ia64, nios2, sh, and sparcAdhemerval Zanella Netto
Not all architectures added clone3 syscall. Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-08-08Add PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG etc. from Linux 6.4 to sys/ptrace.hJoseph Myers
Linux 6.4 adds new constants PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG and PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG. Add those to all relevant sys/ptrace.h headers, along with adding the associated argument structure to bits/ptrace-shared.h (named struct __ptrace_sud_config there following the usual convention for such structures). Tested for x86_64 and with build-many-glibcs.py.
2023-07-17configure: Use autoconf 2.71Siddhesh Poyarekar
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>
2023-06-14Add the wcslcpy, wcslcat functionsFlorian Weimer
These functions are about to be added to POSIX, under Austin Group issue 986. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-06-14Implement strlcpy and strlcat [BZ #178]Florian Weimer
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>
2023-05-23Fix misspellings in sysdeps/unix -- BZ 25337Paul Pluzhnikov
Applying this commit results in bit-identical rebuild of libc.so.6 math/libm.so.6 elf/ld-linux-x86-64.so.2 mathvec/libmvec.so.1 Reviewed-by: Florian Weimer <fweimer@redhat.com>
2023-04-03math: Remove the error handling wrapper from fmod and fmodfAdhemerval Zanella Netto
The error handling is moved to sysdeps/ieee754 version with no SVID support. The compatibility symbol versions still use the wrapper with SVID error handling around the new code. There is no new symbol version nor compatibility code on !LIBM_SVID_COMPAT targets (e.g. riscv). The ia64 is unchanged, since it still uses the arch specific __libm_error_region on its implementation. For both i686 and m68k, which provive arch specific implementation, wrappers are added so no new symbol are added (which would require to change the implementations). It shows an small improvement, the results for fmod: Architecture | Input | master | patch -----------------|-----------------|----------|-------- x86_64 (Ryzen 9) | subnormals | 12.5049 | 9.40992 x86_64 (Ryzen 9) | normal | 296.939 | 296.738 x86_64 (Ryzen 9) | close-exponents | 16.0244 | 13.119 aarch64 (N1) | subnormal | 6.81778 | 4.33313 aarch64 (N1) | normal | 155.620 | 152.915 aarch64 (N1) | close-exponents | 8.21306 | 5.76138 armhf (N1) | subnormal | 15.1083 | 14.5746 armhf (N1) | normal | 244.833 | 241.738 armhf (N1) | close-exponents | 21.8182 | 22.457 Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
2023-03-02C2x scanf binary constant handlingJoseph Myers
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.
2023-02-20Linux: Assume and consolidate getpeername wire-up syscallAdhemerval Zanella
And disable if kernel does not support it. 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>
2023-02-20Linux: Assume and consolidate getsockname wire-up syscallAdhemerval Zanella
And disable if kernel does not support it. 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>
2023-02-20Linux: Move wordsize-32 Version to defaultAdhemerval Zanella
And remove redundant entries on other architectures Version. The version for fallocate64 was supposed to be 2.10, but it was then added to 32-bit platforms in 2.11 because it mistakenly wasn't exported for them in 2.10 (see the commit message for 1f3615a1c97a030bca59f728f998947f852679b9). The linux/generic did not exist before 2.15, i.e. when the tile ports were added (and microblaze did not exist before 2.18), which explains those differences but also illustrates that "2.11 for 32-bit, 2.10 for 64-bit" should be sufficient since versions older than the minimum for the architecture are automatically adjusted. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2023-02-16C2x strtol binary constant handlingJoseph Myers
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.
2023-01-06Update copyright dates with scripts/update-copyrightsJoseph Myers
2022-12-13Allow _Qp_fgt in sparc64 localplt.dataJoseph Myers
A recent GCC change resulted in localplt test failures on sparc64 because of references to _Qp_fgt. This is analogous to all the other floating-point symbols allowed in localplt.data, so it seems appropriate to allow this one as well. Tested with build-many-glibcs.py for sparc64-linux-gnu (GCC mainline), where it fixes the test failure.
2022-12-07Linux: Assume and consolidate shutdown wire-up syscallAdhemerval Zanella Netto
And disable if kernel does not support it. 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>
2022-12-07Linux: Assume and consolidate listen wire-up syscallAdhemerval Zanella Netto
And disable if kernel does not support it. 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>
2022-12-07Linux: Assume and consolidate socketpair wire-up syscallAdhemerval Zanella Netto
And disable if kernel does not support it. 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>
2022-12-07Linux: Assume and consolidate socket wire-up syscallAdhemerval Zanella Netto
And disable if kernel does not support it. 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>
2022-12-07Linux: Assume and consolidate bind wire-up syscallAdhemerval Zanella Netto
And disable if kernel does not support it. 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>
2022-11-08Linux: Add ppoll fortify symbol for 64 bit time_t (BZ# 29746)Adhemerval Zanella
Similar to ppoll, the poll.h header needs to redirect the poll call to a proper fortified ppoll with 64 bit time_t support. The implementation is straightforward, just need to add a similar check as __poll_chk and call the 64 bit time_t ppoll version. The debug fortify tests are also extended to cover 64 bit time_t for affected ABIs. Unfortunately it requires an aditional symbol, which makes backport tricky. One possibility is to add a static inline version if compiler supports is and call abort instead of __chk_fail, so fortified version will call __poll64 in the end. Another possibility is to just remove the fortify support for _TIME_BITS=64. Checked on i686-linux-gnu.
2022-11-03elf: Rework exception handling in the dynamic loader [BZ #25486]Florian Weimer
The old exception handling implementation used function interposition to replace the dynamic loader implementation (no TLS support) with the libc implementation (TLS support). This results in problems if the link order between the dynamic loader and libc is reversed (bug 25486). The new implementation moves the entire implementation of the exception handling functions back into the dynamic loader, using THREAD_GETMEM and THREAD_SETMEM for thread-local data support. These depends on Hurd support for these macros, added in commit b65a82e4e757c1e6cb7073916 ("hurd: Add THREAD_GET/SETMEM/_NC"). One small obstacle is that the exception handling facilities are used before the TCB has been set up, so a check is needed if the TCB is available. If not, a regular global variable is used to store the exception handling information. Also rename dl-error.c to dl-catch.c, to avoid confusion with the dlerror function. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-10-18Introduce <pointer_guard.h>, extracted from <sysdep.h>Florian Weimer
This allows us to define a generic no-op version of PTR_MANGLE and PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources, avoiding an unintended loss of hardening due to missing include files or unlucky header inclusion ordering. In i386 and x86_64, we can avoid a <tls.h> dependency in the C code by using the computed constant from <tcb-offsets.h>. <sysdep.h> no longer includes these definitions, so there is no cyclic dependency anymore when computing the <tcb-offsets.h> constants. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2022-10-10Expose all MAP_ constants in <sys/mman.h> unconditionally (bug 29375)Andreas Schwab
POSIX reserves the MAP_ prefix for <sys/mman.h>, so there is no need to conditionalize their definitions on feature test macros.
2022-08-04Remove ldd libc4 supportAdhemerval Zanella
The older libc versions are obsolete for over twenty years now.
2022-08-04Remove left over LD_LIBRARY_VERSION usagesAdhemerval Zanella
The environment variable was removed by d2db60d8d830ef68c8d20a77ac3572d610aa40b1.
2022-07-22stdlib: Add arc4random, arc4random_buf, and arc4random_uniform (BZ #4417)Adhemerval Zanella Netto
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
2022-07-06stdlib: Implement mbrtoc8, c8rtomb, and the char8_t typedef.Tom Honermann
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>
2022-07-05linux: Add mount_setattrAdhemerval Zanella
It was added on Linux 5.12 (2a1867219c7b27f928e2545782b86daaf9ad50bd) to allow change the properties of a mount or a mount tree using file descriptors which the new mount api is based on. Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-07-05linux: Add open_treeAdhemerval Zanella
It was added on Linux 5.2 (a07b20004793d8926f78d63eb5980559f7813404) to return a O_PATH-opened file descriptor to an existing mountpoint. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-07-05linux: Add fspickAdhemerval Zanella
It was added on Linux 5.2 (cf3cba4a429be43e5527a3f78859b1bfd9ebc5fb) that can be used to pick an existing mountpoint into an filesystem context which can thereafter be used to reconfigure a superblock with fsconfig syscall. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-07-05linux: Add fsconfigAdhemerval Zanella
It was added on Linux 5.2 (ecdab150fddb42fe6a739335257949220033b782) as a way to a configure filesystem creation context and trigger actions upon it, to be used in conjunction with fsopen, fspick and fsmount. The fsconfig_command commands are currently only defined as an enum, so they can't be checked on tst-mount-consts.py with current test support. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-24linux: Add move_mountAdhemerval Zanella
It was added on Linux 5.2 (2db154b3ea8e14b04fee23e3fdfd5e9d17fbc6ae) as way t move a mount from one place to another and, in the next commit, allow to attach an unattached mount tree. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-06-24linux: Add fsmountAdhemerval Zanella
It was added on 5.2 (93766fbd2696c2c4453dd8e1070977e9cd4e6b6d) to provide a way by which a filesystem opened with fsopen and configured by a series of fsconfig calls can have a detached mount object created for it. Tested-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-24linux: Add fsopenAdhemerval Zanella
It was added on Linux 5.2 (24dcb3d90a1f67fe08c68a004af37df059d74005) to start the process of preparing to create a superblock that will then be mountable, using an fd as a context handle. Tested-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-02linux: Add process_mreleaseAdhemerval Zanella
Added in Linux 5.15 (884a7e5964e06ed93c7771c0d7cf19c09a8946f1), the new syscalls allows a caller to free the memory of a dying target process. Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-06-02linux: Add process_madviseAdhemerval Zanella
It was added on Linux 5.10 (ecb8ac8b1f146915aa6b96449b66dd48984caacc) with the same functionality as madvise but using a pidfd of the target process. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-05-17linux: Add pidfd_send_signalAdhemerval Zanella
This was added on Linux 5.1(3eb39f47934f9d5a3027fe00d906a45fe3a15fad) as a way to avoid the race condition of using kill (where PID might be reused by the kernel between between obtaining the pid and sending the signal). If the siginfo_t argument is NULL then pidfd_send_signal is equivalent to kill. If it is not NULL pidfd_send_signal is equivalent to rt_sigqueueinfo. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-05-17linux: Add pidfd_getfdAdhemerval Zanella
This was added on Linux 5.6 (8649c322f75c96e7ced2fec201e123b2b073bf09) as a way to retrieve a file descriptors for another process though pidfd (created either with CLONE_PIDFD or pidfd_getfd). The functionality is similar to recvmmsg SCM_RIGHTS. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>