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* hurd: keep only required PLTs in ld.soSamuel Thibault2020-11-111-0/+4
| | | | | | | | | | | | | | | | | | | | | 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: In ldconfig, extract the new_sub_entry function from search_dirFlorian Weimer2020-10-301-13/+21
| | | | Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Unify old and new format cache handling code in ld.soFlorian Weimer2020-10-301-142/+145
| | | | | | | 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>
* Make elf.h header self contained.Érico Rolim2020-10-281-6/+0
| | | | | | | | | | | | The elf/elf.h header is shared, verbatim, by the elfutils project. However, elfutils can be used on systems with libcs other than glibc, making the presence of __BEGIN_DECLS, __END_DECLS and <features.h> in the file something that downstream distros may have to add patches for. Furthermore, this file doesn't declare anything with language linkage, so `extern "C" {}` blocks aren't necessary; it also doesn't have any conditional definitions based on feature test macros, making inclusion of features.h unnecessary.
* Reword description of SXID_* tunable propertiesSiddhesh Poyarekar2020-10-221-5/+6
| | | | | | | | | | | | | The SXID_* tunable properties only influence processes that are AT_SECURE, so make that a bit more explicit in the documentation and comment. Revisiting the code after a few years I managed to confuse myself, so I imagine there could be others who may have incorrectly assumed like I did that the SXID_ERASE tunables are not inherited by children of non-AT_SECURE processes. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* rtld: fix typo in commentRolf Eike Beer2020-10-131-1/+1
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* elf: Add missing <dl-procinfo.h> header to elf/dl-usage.cMatheus Castanho2020-10-121-0/+1
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* elf: Do not pass GLRO(dl_platform), GLRO(dl_platformlen) to _dl_important_hwcapsFlorian Weimer2020-10-092-8/+6
| | | | | | | In the current code, the function can easily obtain the information on its own. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Enhance ld.so --help to print HWCAP subdirectoriesFlorian Weimer2020-10-091-0/+62
| | | | Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Add library search path information to ld.so --helpFlorian Weimer2020-10-091-0/+56
| | | | Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Make __rtld_env_path_list and __rtld_search_dirs global variablesFlorian Weimer2020-10-081-26/+27
| | | | | | | | | They have been renamed from env_path_list and rtld_search_dirs to avoid linknamespace issues. This change will allow future use these variables in diagnostics. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Print the full name of the dynamic loader in the ld.so help messageFlorian Weimer2020-10-082-1/+4
| | | | | | | | This requires defining a macro for the full path, matching the -Wl,--dynamic-link= arguments used for linking glibc programs, and ldd script. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Use the term "program interpreter" in the ld.so help messageFlorian Weimer2020-10-081-11/+11
| | | | | | This is the term that the ELF standard itself uses. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Implement ld.so --versionFlorian Weimer2020-10-083-0/+20
| | | | | | | | This prints out version information for the dynamic loader and exits immediately, without further command line processing (which seems to match what some GNU tools do). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Implement ld.so --helpFlorian Weimer2020-10-083-13/+75
| | | | | | | | | | | | | | | --help processing is deferred to the point where the executable has been loaded, so that it is possible to eventually include information from the main executable in the help output. As suggested in the GNU command-line interface guidelines, the help message is printed to standard output, and the exit status is successful. Handle usage errors closer to the GNU command-line interface guidelines. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Record whether paths come from LD_LIBRARY_PATH or --library-pathFlorian Weimer2020-10-084-4/+10
| | | | | | This allows more precise LD_DEBUG diagnostics. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Move ld.so error/help output to _dl_usageFlorian Weimer2020-10-084-26/+65
| | | | | | | Also add a comment to elf/Makefile, explaining why we cannot use config.status for autoconf template processing. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Extract command-line/environment variables state from rtld.cFlorian Weimer2020-10-082-96/+157
| | | | | | | | | Introduce struct dl_main_state and move it to <dl-main.h>. Rename enum mode to enum rtld_mode and add the rtld_mode_ prefix to the enum constants. This avoids the need for putting state that is only needed during startup into the ld.so data segment.
* elf: Implement __rtld_malloc_is_completeFlorian Weimer2020-10-081-0/+8
| | | | | | | | In some cases, it is difficult to determine the kind of malloc based on the execution context, so a function to determine that is helpful. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Revert "Fix missing redirects in testsuite targets"Andreas Schwab2020-10-081-1/+1
| | | | | This reverts commit d5afb38503. The log files are actually created by the various shell scripts that drive the tests.
* elf: Implement _dl_writeFlorian Weimer2020-10-072-1/+57
| | | | | | | | 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>
* elf: Do not search HWCAP subdirectories in statically linked binariesFlorian Weimer2020-10-072-2/+16
| | | | | | | | | This functionality does not seem to be useful since static dlopen is mostly used for iconv/character set conversion and NSS support. gconv modules are loaded with full paths anyway, so that the HWCAP subdirectory logic does not apply. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Set tunable value as well as min/max valuesH.J. Lu2020-09-292-6/+60
| | | | | | | | Some tunable values and their minimum/maximum values must be determinted at run-time. Add TUNABLE_SET_WITH_BOUNDS and TUNABLE_SET_WITH_BOUNDS_FULL to update tunable value together with minimum and maximum values. __tunable_set_val is updated to set tunable value as well as min/max values.
* ld.so: add an --argv0 option [BZ #16124]Vincent Mihalkovic2020-09-294-3/+94
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* Remove internal usage of extensible stat functionsAdhemerval Zanella2020-09-114-6/+6
| | | | | | | | | | | | It replaces the internal usage of __{f,l}xstat{at}{64} with the __{f,l}stat{at}{64}. It should not change the generate code since sys/stat.h explicit defines redirections to internal calls back to xstat* symbols. Checked with a build for all affected ABIs. I also check on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Lukasz Majewski <lukma@denx.de>
* elf.h: Add aarch64 bti/pac dynamic tag constantsMark Wielaard2020-09-071-0/+2
| | | | | | | | Constants double checked against binutils and the ELF for the Arm 64-bit Architecture (AArch64) Release 2020Q2 document. Only BTI PLT is used in glibc, there's no PAC PLT with glibc, and people are expected to use BIND_NOW.
* elf/tst-libc_dlvsym: Add a TEST_COMPAT around some symbol testsAlistair Francis2020-08-271-0/+5
| | | | | | | | | The _sys_errlist and _sys_siglist symbols are deprecated since 2.32. This patch adds a TEST_COMPAT check around the tests. This fixes test failures on new architectures (such as RV32) that don't have this symbol defined. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Change TLS static surplus default back to 1664Florian Weimer2020-07-203-8/+75
| | | | | | | Make the computation in elf/dl-tls.c more transparent, and add an explicit test for the historic value. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Linux: Remove rseq supportFlorian Weimer2020-07-162-12/+1
| | | | | | | | | | | | | | | | | | 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 Nagy2020-07-0815-17/+359
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Nagy2020-07-082-6/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | 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 Nagy2020-07-083-5/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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/+96
| | | | | | | | | | | | | | | | | | | | | | 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>
* elf: Do not signal LA_ACT_CONSISTENT for an empty namespace [BZ #26076]Florian Weimer2020-07-071-2/+8
| | | | | | | | | The auditing interface identifies namespaces by their first loaded module. Once the namespace is empty, it is no longer possible to signal LA_ACT_CONSISTENT for it because the first loaded module is already gone at that point. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Add the __libc_single_threaded variableFlorian Weimer2020-07-0611-6/+548
| | | | | | | | | | | | | | 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 Desnoyers2020-07-062-1/+11
| | | | | | | | | | | | | | | | | | | 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.
* elf: Include <stdbool.h> in <dl-tunables.h> because bool is usedFlorian Weimer2020-06-241-0/+2
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* ld.so: Check for new cache format first and enhance corruption checkFlorian Weimer2020-06-151-12/+15
| | | | | | | | | Now that ldconfig defaults to the new format (only), check for it first. Also apply the corruption check added in commit 2954daf00bb4d ("Add more checks for valid ld.so.cache file (bug 18093)") to the new-format-only case. Suggested-by: Josh Triplett <josh@joshtriplett.org>
* Add "%d" support to _dl_debug_vdprintfH.J. Lu2020-06-091-2/+29
| | | | "%d" will be used to print out signed value.
* dl-runtime: reloc_{offset,index} now functions arch overide'ableVineet Gupta2020-06-052-11/+47
| | | | | | | | | | | | | | | The existing macros are fragile and expect local variables with a certain name. Fix this by defining them as functions with default implementation in a new header dl-runtime.h which arches can override if need be. This came up during ARC port review, hence the need for argument pltgot in reloc_index() which is not needed by existing ports. This patch potentially only affects hppa/x86 ports, build tested for both those configs and a few more. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Replace val with __val in TUNABLE_SET_VAL_IF_VALID_RANGEH.J. Lu2020-06-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | There are: #define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type) \ ({ \ __type min = (__cur)->type.min; \ __type max = (__cur)->type.max; \ \ if ((__type) (__val) >= min && (__type) (val) <= max) \ ^^^ Should be __val { \ (__cur)->val.numval = val; \ ^^^ Should be __val (__cur)->initialized = true; \ } \ }) Luckily since all TUNABLE_SET_VAL_IF_VALID_RANGE usages are TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t); this didn't cause any issues. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Remove extra hwcap mechanism from ldconfigFlorian Weimer2020-05-281-71/+16
| | | | | | | | | | | | | | Historically, this mechanism was used to process "nosegneg" subdirectories, and it is still used to include the "tls" subdirectories. With nosegneg support gone from ld.so, this is part no longer useful. The entire mechanism is not well-designed because it causes the meaning of hwcap bits in ld.so.cache to depend on the kernel version that was used to generate the cache, which makes it difficult to use this mechanism for anything else in the future. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Do not read hwcaps from the vDSO in ld.soFlorian Weimer2020-05-281-110/+0
| | | | | | | | | | This was only ever used for the "nosegneg" flag. This approach for passing hardware capability information creates a subtle dependency between the kernel and userspace, and ld.so.cache contents. It seems inappropriate for toady, where people expect to be able to run system images which very different kernel versions. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Turn _dl_printf, _dl_error_printf, _dl_fatal_printf into functionsFlorian Weimer2020-05-252-1/+32
| | | | | | | | | | | | | | This change makes it easier to set a breakpoint on these calls. This also addresses the issue that including <ldsodefs.h> without <unistd.h> does not result usable _dl_*printf macros because of the use of the STD*_FILENO macros there. (The private symbol for _dl_fatal_printf will go away again once the exception handling implementation is unified between libc and ld.so.) Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf.h: add aarch64 property definitionsSzabolcs Nagy2020-05-211-0/+6
| | | | | | | These property values are specified by the AArch64 ELF ABI and binutils can create binaries marked with them. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf.h: Add PT_GNU_PROPERTYSzabolcs Nagy2020-05-211-0/+1
| | | | | | | This program header type is already used in binaries on x86 and aarch64 targets. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ldconfig: Default to the new format for ld.so.cacheJosh Triplett2020-05-191-2/+2
| | | | glibc has supported this format for close to 20 years.
* Remove NO_CTORS_DTORS_SECTIONS macroFlorian Weimer2020-05-183-56/+1
| | | | | | | | | | | This was originally added to support binutils older than version 2.22: <https://sourceware.org/ml/libc-alpha/2010-12/msg00051.html> Since 2.22 is older than the minimum required binutils version for building glibc, we no longer need this. (The changes do not impact the statically linked startup code.)
* elf: Assert that objects are relocated before their constructors runFlorian Weimer2020-05-181-0/+6
| | | | | | | | | If we try to run constructors before relocation, this is always a dynamic linker bug. An assert is easier to notice than a call via an invalid function pointer (which may not even produce a valid call stack). Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* x86: Move CET control to _dl_x86_feature_control [BZ #25887]H.J. Lu2020-05-181-0/+2
| | | | | | | | | | 1. Include <dl-procruntime.c> to get architecture specific initializer in rtld_global. 2. Change _dl_x86_feature_1[2] to _dl_x86_feature_1. 3. Add _dl_x86_feature_control after _dl_x86_feature_1, which is a struct of 2 bitfields for IBT and SHSTK control This fixes [BZ #25887].
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