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* fork.h: replace with register-atfork.hSamuel Thibault2021-03-291-27/+0
| | | | | | | | | | | | | UNREGISTER_ATFORK is now defined for all ports in register-atfork.h, so most previous includes of fork.h actually only need register-atfork.h now, and cxa_finalize.c does not need an ifdef UNREGISTER_ATFORK any more. The nptl-specific fork generation counters can then go to pthreadP.h, and fork.h be removed. Checked on x86_64-linux-gnu and i686-gnu. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl: Remove __libc_allocate_rtsig, __libc_current_sigrtmax, and ↵Adhemerval Zanella2021-03-261-0/+4
| | | | | | | | __libc_current_sigrtmin The libc version is identical and built with same flags. Checked on x86_64-linux-gnu.
* malloc: Only support zeroing and not arbitrary memset with mtagSzabolcs Nagy2021-03-261-3/+3
| | | | | | | | | | The memset api is suboptimal and does not provide much benefit. Memory tagging only needs a zeroing memset (and only for memory that's sized and aligned to multiples of the tag granule), so change the internal api and the target hooks accordingly. This is to simplify the implementation of the target hook. Reviewed-by: DJ Delorie <dj@redhat.com>
* malloc: Ensure the generic mtag hooks are not usedSzabolcs Nagy2021-03-261-10/+31
| | | | | | | | | | | | | | | | | | Use inline functions instead of macros, because macros can cause unused variable warnings and type conversion issues. We assume these functions may appear in the code but only in dead code paths (hidden by a runtime check), so it's important that they can compile with correct types, but if they are actually used that should be an error. Currently the hooks are only used when USE_MTAG is true which only happens on aarch64 and then the aarch64 specific code is used not this generic header. However followup refactoring will allow the hooks to be used with !USE_MTAG. Note: the const qualifier in the comment was wrong: changing tags is a write operation. Reviewed-by: DJ Delorie <dj@redhat.com>
* Support for multiple versions in versioned_symbol, compat_symbolFlorian Weimer2021-03-251-3/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This essentially folds compat_symbol_unique functionality into compat_symbol. This change eliminates the need for intermediate aliases for defining multiple symbol versions, for both compat_symbol and versioned_symbol. Some binutils versions do not suport multiple versions per symbol on some targets, so aliases are automatically introduced, similar to what compat_symbol_unique did. To reduce symbol table sizes, a configure check is added to avoid these aliases if they are not needed. The new mechanism works with data symbols as well as function symbols, due to the way an assembler-level redirect is used. It is not compatible with weak symbols for old binutils versions, which is why the definition of __malloc_initialize_hook had to be changed. This is not a loss of functionality because weak symbols do not matter to dynamic linking. The placeholder symbol needs repeating in nptl/libpthread-compat.c now that compat_symbol is used, but that seems more obvious than introducing yet another macro. A subtle difference was that compat_symbol_unique made the symbol global automatically. compat_symbol does not do this, so static had to be removed from the definition of __libpthread_version_placeholder. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Change how the symbol_version_reference macro is definedFlorian Weimer2021-03-251-0/+38
| | | | | | | | | | | | A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Legacy unwinder: Remove definition of _Unwind_GetCFAFlorian Weimer2021-03-161-8/+0
| | | | | | | | It is not actually used by the legacy unwinder linked into libc.so, and it conflicts with the unwind-link functionality in libpthread. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* posix: Consolidate register-atforkAdhemerval Zanella2021-03-121-0/+19
| | | | | | | | | | | | | Both htl and nptl uses a different data structure to implement atfork handlers. The nptl one was refactored by 27761a1042d to use a dynarray which simplifies the code. This patch moves the nptl one to be the generic implementation and replace Hurd linked one. Different than previous NPTL, Hurd also uses a global lock, so performance should be similar. Checked on x86_64-linux-gnu, i686-linux-gnu, and with a build for i686-gnu.
* math: Remove mpa files [BZ #15267]Wilco Dijkstra2021-03-111-6/+0
| | | | | | | Finally remove all mpa related files, headers, declarations, probes, unused tables and update makefiles. Reviewed-By: Paul Zimmermann <Paul.Zimmermann@inria.fr>
* Implement _Unwind_Resume in libc on top of <unwind-link.h>Florian Weimer2021-03-011-46/+9
| | | | | | | | Temporarily move the arm _Unwind_Resume implementation to the file used by libpthread. It will be ported to <unwind-link.h> along with the rest of nptl. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Move sysdeps/gnu/unwind-resume.c to sysdeps/generic/unwind-resume.cFlorian Weimer2021-03-011-0/+83
| | | | | | | This change allows architecture-specific sysdeps directories to override it. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* __frame_state_for: Use <unwind-link.h> for unwinder accessFlorian Weimer2021-03-011-13/+8
| | | | Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Implement <unwind-link.h> for dynamically loading the libgcc_s unwinderFlorian Weimer2021-03-012-11/+122
| | | | | | | | | | This will be used to consolidate the libgcc_s access for backtrace and pthread_cancel. Unlike the existing backtrace implementations, it provides some hardening based on pointer mangling. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Reduce the statically linked startup code [BZ #23323]Florian Weimer2021-02-251-1/+5
| | | | | | | | | | | | | | | | | | | 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.
* sysconf: Add _SC_MINSIGSTKSZ/_SC_SIGSTKSZ [BZ #20305]H.J. Lu2021-02-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add _SC_MINSIGSTKSZ for the minimum signal stack size derived from AT_MINSIGSTKSZ, which is the minimum number of bytes of free stack space required in order to gurantee successful, non-nested handling of a single signal whose handler is an empty function, and _SC_SIGSTKSZ which is the suggested minimum number of bytes of stack space required for a signal stack. If AT_MINSIGSTKSZ isn't available, sysconf (_SC_MINSIGSTKSZ) returns MINSIGSTKSZ. On Linux/x86 with XSAVE, the signal frame used by kernel is composed of the following areas and laid out as: ------------------------------ | alignment padding | ------------------------------ | xsave buffer | ------------------------------ | fsave header (32-bit only) | ------------------------------ | siginfo + ucontext | ------------------------------ Compute AT_MINSIGSTKSZ value as size of xsave buffer + size of fsave header (32-bit only) + size of siginfo and ucontext + alignment padding. If _SC_SIGSTKSZ_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are redefined as /* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ). */ # undef SIGSTKSZ # define SIGSTKSZ sysconf (_SC_SIGSTKSZ) /* Minimum stack size for a signal handler: SIGSTKSZ. */ # undef MINSIGSTKSZ # define MINSIGSTKSZ SIGSTKSZ Compilation will fail if the source assumes constant MINSIGSTKSZ or SIGSTKSZ. The reason for not simply increasing the kernel's MINSIGSTKSZ #define (apart from the fact that it is rarely used, due to glibc's shadowing definitions) was that userspace binaries will have baked in the old value of the constant and may be making assumptions about it. For example, the type (char [MINSIGSTKSZ]) changes if this #define changes. This could be a problem if an newly built library tries to memcpy() or dump such an object defined by and old binary. Bounds-checking and the stack sizes passed to things like sigaltstack() and makecontext() could similarly go wrong.
* Use <startup.h> in __libc_init_secureH.J. Lu2021-01-191-0/+26
| | | | | | | | | Since __libc_init_secure is called before ARCH_SETUP_TLS, it must use "int $0x80" for system calls in i386 static PIE. Add startup_getuid, startup_geteuid, startup_getgid and startup_getegid to <startup.h>. Update __libc_init_secure to use them. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ldconfig/x86: Store ISA level in cache and aux cacheH.J. Lu2021-01-134-11/+86
| | | | | | | | | | | Store ISA level in the portion of the unused upper 32 bits of the hwcaps field in cache and the unused pad field in aux cache. ISA level is stored and checked only for shared objects in glibc-hwcaps subdirectories. The shared objects in the default directories aren't checked since there are no fallbacks for these shared objects. Tested on x86-64-v2, x86-64-v3 and x86-64-v4 machines with --disable-hardcoded-path-in-tests and --enable-hardcoded-path-in-tests.
* Move generic nan-pseudo-number.h to ldbl-96Siddhesh Poyarekar2021-01-041-31/+0
| | | | | The concept of pseudo number formats only exists in the realm of the 96 bit long double format.
* Update copyright dates with scripts/update-copyrightsPaul Eggert2021-01-02142-142/+142
| | | | | | | | | | | | | | | | I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 6694 files FOO. I then removed trailing white space from benchtests/bench-pthread-locks.c and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this diagnostic from Savannah: remote: *** pre-commit check failed ... remote: *** error: lines with trailing whitespace found remote: error: hook declined to update refs/heads/master
* x86 long double: Consider pseudo numbers as signalingSiddhesh Poyarekar2020-12-301-0/+31
| | | | | | | Add support to treat pseudo-numbers specially and implement x86 version to consider all of them as signaling. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* malloc: Basic support for memory tagging in the malloc() familyRichard Earnshaw2020-12-211-0/+52
| | | | | | | | | | | | | | | | | This patch adds the basic support for memory tagging. Various flavours are supported, particularly being able to turn on tagged memory at run-time: this allows the same code to be used on systems where memory tagging support is not present without neededing a separate build of glibc. Also, depending on whether the kernel supports it, the code will use mmap for the default arena if morecore does not, or cannot support tagged memory (on AArch64 it is not available). All the hooks use function pointers to allow this to work without needing ifuncs. Reviewed-by: DJ Delorie <dj@redhat.com>
* profil-counter: Add missing SIGINFO caseSamuel Thibault2020-12-211-0/+10
| | | | | | When SA_SIGINFO is available, sysdeps/posix/s?profil.c use it, so we have to fix the __profil_counter function accordingly, using sigcontextinfo.h's sigcontext_get_pc.
* ieee754: Remove unused __sin32 and __cos32Anssi Hannula2020-12-181-2/+0
| | | | | The __sin32 and __cos32 functions were only used in the now removed slow path of asin and acos.
* elf: Pass the fd to note processingSzabolcs Nagy2020-12-112-5/+6
| | | | | | | | | | | | | | To handle GNU property notes on aarch64 some segments need to be mmaped again, so the fd of the loaded ELF module is needed. When the fd is not available (kernel loaded modules), then -1 is passed. The fd is passed to both _dl_process_pt_gnu_property and _dl_process_pt_note for consistency. Target specific note processing functions are updated accordingly. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Process glibc-hwcaps subdirectories in ldconfigFlorian Weimer2020-12-042-2/+66
| | | | | | | | Libraries from these subdirectories are added to the cache with a special hwcap bit DL_CACHE_HWCAP_EXTENSION, so that they are ignored by older dynamic loaders. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Add extension mechanism to ld.so.cacheFlorian Weimer2020-12-041-1/+122
| | | | | | | | | | A previously unused new-format header field is used to record the address of an extension directory. This change adds a demo extension which records the version of ldconfig which builds a file. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Add endianness markup to ld.so.cache (bug 27008)Florian Weimer2020-12-041-1/+63
| | | | | | | | | Use a reserved byte in the new format cache header to indicate whether the file is in little endian or big endian format. Eventually, this information could be used to provide a unified cache for qemu-user and similiar scenarios. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Add glibc-hwcaps support for LD_LIBRARY_PATHFlorian Weimer2020-12-041-5/+15
| | | | | | | | | | | | | | | | | | | | This hacks non-power-set processing into _dl_important_hwcaps. Once the legacy hwcaps handling goes away, the subdirectory handling needs to be reworked, but it is premature to do this while both approaches are still supported. ld.so supports two new arguments, --glibc-hwcaps-prepend and --glibc-hwcaps-mask. Each accepts a colon-separated list of glibc-hwcaps subdirectory names. The prepend option adds additional subdirectories that are searched first, in the specified order. The mask option restricts the automatically selected subdirectories to those listed in the option argument. For example, on systems where /usr/lib64 is on the library search path, --glibc-hwcaps-prepend=valgrind:debug causes the dynamic loader to search the directories /usr/lib64/glibc-hwcaps/valgrind and /usr/lib64/glibc-hwcaps/debug just before /usr/lib64 is searched. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Introduce enum opt_format in the ldconfig implementationFlorian Weimer2020-11-261-1/+8
| | | | Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl: Move stack list variables into _rtld_globalFlorian Weimer2020-11-161-3/+16
| | | | | | | | | Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT, formerly __wait_lookup_done) can be implemented directly in ld.so, eliminating the unprotected GL (dl_wait_lookup_done) function pointer. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Remove tls.h inclusion from internal errno.hAdhemerval Zanella2020-11-131-0/+1
| | | | | | | | | | | | The tls.h inclusion is not really required and limits possible definition on more arch specific headers. This is a cleanup to allow inline functions on sysdep.h, more specifically on i386 and ia64 which requires to access some tls definitions its own. No semantic changes expected, checked with a build against all affected ABIs.
* struct _Unwind_Exception alignment should not depend on compiler flagsFlorian Weimer2020-11-111-9/+15
| | | | | | | | | | | | __attribute__((__aligned__)) selects an alignment that depends on the micro-architecture selected by GCC flags. Enabling vector extensions may increase the allignment. This is a problem when building glibc as a collection of ELF multilibs with different GCC flags because ld.so and libc.so/libpthread.so/&c may end up with a different layout of struct pthread because of the changing offset of its struct _Unwind_Exception field. Tested-By: Matheus Castanho <msc@linux.ibm.com>
* hurd: keep only required PLTs in ld.soSamuel Thibault2020-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | We need NO_RTLD_HIDDEN because of the need for PLT calls in ld.so. See Roland's comment in https://sourceware.org/bugzilla/show_bug.cgi?id=15605 "in the Hurd it's crucial that calls like __mmap be the libc ones instead of the rtld-local ones after the bootstrap phase, when the dynamic linker is being used for dlopen and the like." We used to just avoid all hidden use in the rtld ; this commit switches to keeping only those that should use PLT calls, i.e. essentially those defined in sysdeps/mach/hurd/dl-sysdep.c: __assert_fail __assert_perror_fail __*stat64 _exit This fixes a few startup issues, notably the call to __tunable_get_val that is made before PLTs are set up.
* elf: Unify old and new format cache handling code in ld.soFlorian Weimer2020-10-301-4/+13
| | | | | | | struct file_entry_new starts with the fields of struct file_entry, so the code can be shared if the size computation is made dynamic. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* linux: Add {f}stat{at} y2038 supportAdhemerval Zanella2020-10-091-0/+6
| | | | | | | | | | | | | | | | | | | | A new struct __stat{64}_t64 type is added with the required __timespec64 time definition. Only LFS is added, 64-bit time with 32-bit offsets is not supposed to be supported (no existing glibc configuration supports such a combination). It is done with an extra __NR_statx call plus a conversion to the new __stat{64}_t64 type. The statx call is done only for 32-bit time_t ABIs. Internally some extra routines to copy from/to struct stat{64} to struct __stat{64} used on multiple implementations (stat, fstat, lstat, and fstatat) are added on a extra implementation (stat_t64_cp.c). Alse some extra routines to copy from statx to __stat{64} is added on statx_cp.c. Checked with a build for all affected ABIs. I also checked on x86_64, i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x. Reviewed-by: Lukasz Majewski <lukma@denx.de>
* Remove mknod wrapper functions, move them to symbolsAdhemerval Zanella2020-10-091-0/+1
| | | | | | | | | | | | | | | | | | | This patch removes the mknod and mknodat static wrapper and add the symbols on the libc with the expected names. Both the prototypes of the internal symbol linked by the static wrappers and the inline redirectors are also removed from the installed sys/stat.h header file. The wrapper implementation license LGPL exception is also removed since it is no longer statically linked to binaries. Internally the _STAT_VER* definitions are moved to the arch-specific xstatver.h file. Checked with a build for all affected ABIs. I also checked on x86_64, i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x. Reviewed-by: Lukasz Majewski <lukma@denx.de>
* Remove stat wrapper functions, move them to exported symbolsAdhemerval Zanella2020-10-091-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | This patch removes the stat, stat64, lstat, lstat64, fstat, fstat64, fstatat, and fstatat64 static wrapper and add the symbol on the libc with the expected names. Both the prototypes of the internal symbol linked by the static wrappers and the inline redirectors are also removed from the installed sys/stat.h header file. The wrapper implementation license LGPL exception is also removed since it is no longer statically linked to binaries. Internally the _STAT_VER* definitions are moved to a arch-specific xstatver.h file. The internal defines that redirects internals {f}stat{at} to their {f}xstat{at} counterparts are removed for Linux (!NO_RTLD_HIDDEN). Hurd still requires them since {f}stat{at} pulls extra objects that makes the loader build fail otherwise (I haven't dig into why exactly). Checked with a build for all affected ABIs. I also checked on x86_64, i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x. Reviewed-by: Lukasz Majewski <lukma@denx.de>
* elf: Do not pass GLRO(dl_platform), GLRO(dl_platformlen) to _dl_important_hwcapsFlorian Weimer2020-10-091-6/+6
| | | | | | | In the current code, the function can easily obtain the information on its own. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Record whether paths come from LD_LIBRARY_PATH or --library-pathFlorian Weimer2020-10-081-2/+4
| | | | | | This allows more precise LD_DEBUG diagnostics. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Implement _dl_writeFlorian Weimer2020-10-071-0/+6
| | | | | | | | The generic version is parallel to _dl_writev. It cannot use _dl_writev directly because the errno value needs to be obtained under a lock. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Linux: Remove rseq supportFlorian Weimer2020-07-161-26/+0
| | | | | | | | | | | | | | | | | | The kernel ABI is not finalized, and there are now various proposals to change the size of struct rseq, which would make the glibc ABI dependent on the version of the kernels used for building glibc. This is of course not acceptable. This reverts commit 48699da1c468543ade14777819bd1b4d652709de ("elf: Support at least 32-byte alignment in static dlopen"), commit 8f4632deb3545b2949cec5454afc3cb21a0024ea ("Linux: rseq registration tests"), commit 6e29cb3f61ff5432c78a1c84b0d9b123a350ab36 ("Linux: Use rseq in sched_getcpu if available"), and commit 0c76fc3c2b346dc5401dc055d97d4279632b0fb3 ("Linux: Perform rseq registration at C startup and thread creation"), resolving the conflicts introduced by the ARC port and the TLS static surplus changes. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Avoid using up static TLS surplus for optimizations [BZ #25051]Szabolcs Nagy2020-07-081-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | On some targets static TLS surplus area can be used opportunistically for dynamically loaded modules such that the TLS access then becomes faster (TLSDESC and powerpc TLS optimization). However we don't want all surplus TLS to be used for this optimization because dynamically loaded modules with initial-exec model TLS can only use surplus TLS. The new contract for surplus static TLS use is: - libc.so can have up to 192 bytes of IE TLS, - other system libraries together can have up to 144 bytes of IE TLS. - Some "optional" static TLS is available for opportunistic use. The optional TLS is now tunable: rtld.optional_static_tls, so users can directly affect the allocated static TLS size. (Note that module unloading with dlclose does not reclaim static TLS. After the optional TLS runs out, TLS access is no longer optimized to use static TLS.) The default setting of rtld.optional_static_tls is 512 so the surplus TLS is 3*192 + 4*144 + 512 = 1664 by default, the same as before. Fixes BZ #25051. Tested on aarch64-linux-gnu and x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Account static TLS surplus for audit modulesSzabolcs Nagy2020-07-081-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | The new static TLS surplus size computation is surplus_tls = 192 * (nns-1) + 144 * nns + 512 where nns is controlled via the rtld.nns tunable. This commit accounts audit modules too so nns = rtld.nns + audit modules. rtld.nns should only include the namespaces required by the application, namespaces for audit modules are accounted on top of that so audit modules don't use up the static TLS that is reserved for the application. This allows loading many audit modules without tuning rtld.nns or using up static TLS, and it fixes FAIL: elf/tst-auditmany Note that DL_NNS is currently a hard upper limit for nns, and if rtld.nns + audit modules go over the limit that's a fatal error. By default rtld.nns is 4 which allows 12 audit modules. Counting the audit modules is based on existing audit string parsing code, we cannot use GLRO(dl_naudit) before the modules are actually loaded.
* rtld: Add rtld.nns tunable for the number of supported namespacesSzabolcs Nagy2020-07-081-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TLS_STATIC_SURPLUS is 1664 bytes currently which is not enough to support DL_NNS (== 16) number of dynamic link namespaces, if we assume 192 bytes of TLS are reserved for libc use and 144 bytes are reserved for other system libraries that use IE TLS. A new tunable is introduced to control the number of supported namespaces and to adjust the surplus static TLS size as follows: surplus_tls = 192 * (rtld.nns-1) + 144 * rtld.nns + 512 The default is rtld.nns == 4 and then the surplus TLS size is the same as before, so the behaviour is unchanged by default. If an application creates more namespaces than the rtld.nns setting allows, then it is not guaranteed to work, but the limit is not checked. So existing usage will continue to work, but in the future if an application creates more than 4 dynamic link namespaces then the tunable will need to be set. In this patch DL_NNS is a fixed value and provides a maximum to the rtld.nns setting. Static linking used fixed 2048 bytes surplus TLS, this is changed so the same contract is used as for dynamic linking. With static linking DL_NNS == 1 so rtld.nns tunable is forced to 1, so by default the surplus TLS is reduced to 144 + 512 = 656 bytes. This change is not expected to cause problems. Tested on aarch64-linux-gnu and x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Clean up PT_NOTE and add PT_GNU_PROPERTY handlingSzabolcs Nagy2020-07-082-12/+15
| | | | | | | | | | | | | | | | | | | | | | Add generic code to handle PT_GNU_PROPERTY notes. Invalid content is ignored, _dl_process_pt_gnu_property is always called after PT_LOAD segments are mapped and it has no failure modes. Currently only one NT_GNU_PROPERTY_TYPE_0 note is handled, which contains target specific properties: the _dl_process_gnu_property hook is called for each property. The old _dl_process_pt_note and _rtld_process_pt_note differ in how the program header is read. The old _dl_process_pt_note is called before PT_LOAD segments are mapped and _rtld_process_pt_note is called after PT_LOAD segments are mapped. The old _rtld_process_pt_note is removed and _dl_process_pt_note is always called after PT_LOAD segments are mapped and now it has no failure modes. The program headers are scanned backwards so that PT_NOTE can be skipped if PT_GNU_PROPERTY exists. Co-Authored-By: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* string: Use tls-internal on strerror_lAdhemerval Zanella2020-07-072-0/+2
| | | | | | | | | | The buffer allocation uses the same strategy of strsignal. Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, and s390x-linux-gnu. Tested-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* string: Remove old TLS usage on strsignalAdhemerval Zanella2020-07-074-0/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The per-thread state is refactored two use two strategies: 1. The default one uses a TLS structure, which will be placed in the static TLS space (using __thread keyword). 2. Linux allocates via struct pthread and access it through THREAD_* macros. The default strategy has the disadvantage of increasing libc.so static TLS consumption and thus decreasing the possible surplus used in some scenarios (which might be mitigated by BZ#25051 fix). It is used only on Hurd, where accessing the thread storage in the in single thread case is not straightforward (afaiu, Hurd developers could correct me here). The fallback static allocation used for allocation failure is also removed: defining its size is problematic without synchronizing with translated messages (to avoid partial translation) and the resulting usage is not thread-safe. Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, and s390x-linux-gnu. Tested-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* signal: Move sys_siglist to a compat symbolAdhemerval Zanella2020-07-072-0/+48
| | | | | | | | | | | | | | | | | | | The symbol was deprecated by strsignal and its usage imposes issues such as copy relocations. Its internal name is changed to __sys_siglist and __sys_sigabbrev to avoid static linking usage. The compat code is also refactored, since both Linux and Hurd usage the same strategy: export the same array with different object sizes. The libSegfault change avoids calling strsignal on the SIGFAULT signal handler (the current usage is already sketchy, adding a call that potentially issue locale internal function is even sketchier). Checked on x86_64-linux-gnu and i686-linux-gnu. I also run a check-abi on all affected platforms. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Add the __libc_single_threaded variableFlorian Weimer2020-07-061-0/+1
| | | | | | | | | | | | | | The variable is placed in libc.so, and it can be true only in an outer libc, not libcs loaded via dlmopen or static dlopen. Since thread creation from inner namespaces does not work, pthread_create can update __libc_single_threaded directly. Using __libc_early_init and its initial flag, implementation of this variable is very straightforward. A future version may reset the flag during fork (but not in an inner namespace), or after joining all threads except one. Reviewed-by: DJ Delorie <dj@redhat.com>
* Linux: Perform rseq registration at C startup and thread creationMathieu Desnoyers2020-07-061-0/+26
| | | | | | | | | | | | | | | | | | | Register rseq TLS for each thread (including main), and unregister for each thread (excluding main). "rseq" stands for Restartable Sequences. See the rseq(2) man page proposed here: https://lkml.org/lkml/2018/9/19/647 Those are based on glibc master branch commit 3ee1e0ec5c. The rseq system call was merged into Linux 4.18. The TLS_STATIC_SURPLUS define is increased to leave additional room for dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working. The increase (76 bytes) is larger than 32 bytes because it has not been increased in quite a while. The cost in terms of additional TLS storage is quite significant, but it will also obscure some initial-exec-related dlopen failures.
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