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* elf: Avoid re-initializing already allocated TLS in dlopen (bug 31717)Florian Weimer2024-08-051-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old code used l_init_called as an indicator for whether TLS initialization was complete. However, it is possible that TLS for an object is initialized, written to, and then dlopen for this object is called again, and l_init_called is not true at this point. Previously, this resulted in TLS being initialized twice, discarding any interim writes (technically introducing a use-after-free bug even). This commit introduces an explicit per-object flag, l_tls_in_slotinfo. It indicates whether _dl_add_to_slotinfo has been called for this object. This flag is used to avoid double-initialization of TLS. In update_tls_slotinfo, the first_static_tls micro-optimization is removed because preserving the initalization flag for subsequent use by the second loop for static TLS is a bit complicated, and another per-object flag does not seem to be worth it. Furthermore, the l_init_called flag is dropped from the second loop (for static TLS initialization) because l_need_tls_init on its own prevents double-initialization. The remaining l_init_called usage in resize_scopes and update_scopes is just an optimization due to the use of scope_has_map, so it is not changed in this commit. The isupper check ensures that libc.so.6 is TLS is not reverted. Such a revert happens if l_need_tls_init is not cleared in _dl_allocate_tls_init for the main_thread case, now that l_init_called is not checked anymore in update_tls_slotinfo in elf/dl-open.c. Reported-by: Jonathon Anderson <janderson@rice.edu> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Clarify and invert second argument of _dl_allocate_tls_initFlorian Weimer2024-08-051-3/+1
| | | | | | | Also remove an outdated comment: _dl_allocate_tls_init is called as part of pthread_create. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Support recursive use of dynamic TLS in interposed mallocFlorian Weimer2024-07-011-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that quite a few applications use bundled mallocs that have been built to use global-dynamic TLS (instead of the recommended initial-exec TLS). The previous workaround from commit afe42e935b3ee97bac9a7064157587777259c60e ("elf: Avoid some free (NULL) calls in _dl_update_slotinfo") does not fix all encountered cases unfortunatelly. This change avoids the TLS generation update for recursive use of TLS from a malloc that was called during a TLS update. This is possible because an interposed malloc has a fixed module ID and TLS slot. (It cannot be unloaded.) If an initially-loaded module ID is encountered in __tls_get_addr and the dynamic linker is already in the middle of a TLS update, use the outdated DTV, thus avoiding another call into malloc. It's still necessary to update the DTV to the most recent generation, to get out of the slow path, which is why the check for recursion is needed. The bookkeeping is done using a global counter instead of per-thread flag because TLS access in the dynamic linker is tricky. All this will go away once the dynamic linker stops using malloc for TLS, likely as part of a change that pre-allocates all TLS during pthread_create/dlopen. Fixes commit d2123d68275acc0f061e73d5f86ca504e0d5a344 ("elf: Fix slow tls access after dlopen [BZ #19924]"). Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* powerpc: Add HWCAP3/HWCAP4 data to TCB for Power Architecture.Manjunath Matti2024-03-191-0/+2
| | | | | | | | | | | | | This patch adds a new feature for powerpc. In order to get faster access to the HWCAP3/HWCAP4 masks, similar to HWCAP/HWCAP2 (i.e. for implementing __builtin_cpu_supports() in GCC) without the overhead of reading them from the auxiliary vector, we now reserve space for them in the TCB. This is an ABI change for GLIBC 2.39. Suggested-by: Peter Bergner <bergner@linux.ibm.com> Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
* Update copyright dates with scripts/update-copyrightsPaul Eggert2024-01-011-1/+1
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* elf: Always provide _dl_get_dl_main_map in libc.aH.J. Lu2024-01-011-4/+3
| | | | | Always provide _dl_get_dl_main_map in libc.a. It will be used by x86 to process PT_GNU_PROPERTY segment.
* Revert "elf: Always call destructors in reverse constructor order (bug 30785)"Florian Weimer2023-10-181-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 6985865bc3ad5b23147ee73466583dd7fdf65892. Reason for revert: The commit changes the order of ELF destructor calls too much relative to what applications expect or can handle. In particular, during process exit and _dl_fini, after the revert commit, we no longer call the destructors of the main program first; that only happens after some dlopen'ed objects have been destructed. This robs applications of an opportunity to influence destructor order by calling dlclose explicitly from the main program's ELF destructors. A couple of different approaches involving reverse constructor order were tried, and none of them worked really well. It seems we need to keep the dependency sorting in _dl_fini. There is also an ambiguity regarding nested dlopen calls from ELF constructors: Should those destructors run before or after the object that called dlopen? Commit 6985865bc3ad5b2314 used reverse order of the start of ELF constructor calls for destructors, but arguably using completion of constructors is more correct. However, that alone is not sufficient to address application compatibility issues (it does not change _dl_fini ordering at all).
* elf: Add dummy declaration of _dl_audit_objclose for !SHAREDFlorian Weimer2023-09-261-1/+8
| | | | | | This allows us to avoid some #ifdef SHARED conditionals. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Always call destructors in reverse constructor order (bug 30785)Florian Weimer2023-09-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current implementation of dlclose (and process exit) re-sorts the link maps before calling ELF destructors. Destructor order is not the reverse of the constructor order as a result: The second sort takes relocation dependencies into account, and other differences can result from ambiguous inputs, such as cycles. (The force_first handling in _dl_sort_maps is not effective for dlclose.) After the changes in this commit, there is still a required difference due to dlopen/dlclose ordering by the application, but the previous discrepancies went beyond that. A new global (namespace-spanning) list of link maps, _dl_init_called_list, is updated right before ELF constructors are called from _dl_init. In dl_close_worker, the maps variable, an on-stack variable length array, is eliminated. (VLAs are problematic, and dlclose should not call malloc because it cannot readily deal with malloc failure.) Marking still-used objects uses the namespace list directly, with next and next_idx replacing the done_index variable. After marking, _dl_init_called_list is used to call the destructors of now-unused maps in reverse destructor order. These destructors can call dlopen. Previously, new objects do not have l_map_used set. This had to change: There is no copy of the link map list anymore, so processing would cover newly opened (and unmarked) mappings, unloading them. Now, _dl_init (indirectly) sets l_map_used, too. (dlclose is handled by the existing reentrancy guard.) After _dl_init_called_list traversal, two more loops follow. The processing order changes to the original link map order in the namespace. Previously, dependency order was used. The difference should not matter because relocation dependencies could already reorder link maps in the old code. The changes to _dl_fini remove the sorting step and replace it with a traversal of _dl_init_called_list. The l_direct_opencount decrement outside the loader lock is removed because it appears incorrect: the counter manipulation could race with other dynamic loader operations. tst-audit23 needs adjustments to the changes in LA_ACT_DELETE notifications. The new approach for checking la_activity should make it clearer that la_activty calls come in pairs around namespace updates. The dependency sorting test cases need updates because the destructor order is always the opposite order of constructor order, even with relocation dependencies or cycles present. There is a future cleanup opportunity to remove the now-constant force_first and for_fini arguments from the _dl_sort_maps function. Fixes commit 1df71d32fe5f5905ffd5d100e5e9ca8ad62 ("elf: Implement force_first handling in _dl_sort_maps_dfs (bug 28937)"). Reviewed-by: DJ Delorie <dj@redhat.com>
* elf: Fix slow tls access after dlopen [BZ #19924]Szabolcs Nagy2023-09-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In short: __tls_get_addr checks the global generation counter and if the current dtv is older then _dl_update_slotinfo updates dtv up to the generation of the accessed module. So if the global generation is newer than generation of the module then __tls_get_addr keeps hitting the slow dtv update path. The dtv update path includes a number of checks to see if any update is needed and this already causes measurable tls access slow down after dlopen. It may be possible to detect up-to-date dtv faster. But if there are many modules loaded (> TLS_SLOTINFO_SURPLUS) then this requires at least walking the slotinfo list. This patch tries to update the dtv to the global generation instead, so after a dlopen the tls access slow path is only hit once. The modules with larger generation than the accessed one were not necessarily synchronized before, so additional synchronization is needed. This patch uses acquire/release synchronization when accessing the generation counter. Note: in the x86_64 version of dl-tls.c the generation is only loaded once, since relaxed mo is not faster than acquire mo load. I have not benchmarked this. Tested by Adhemerval Zanella on aarch64, powerpc, sparc, x86 who reported that it fixes the performance issue of bug 19924. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* sparc: Fix la_symbind for bind-now (BZ 23734)Adhemerval Zanella2023-07-121-2/+2
| | | | | | | | | | | | | | | | | | | | | The sparc ABI has multiple cases on how to handle JMP_SLOT relocations, (sparc_fixup_plt/sparc64_fixup_plt). For BINDNOW, _dl_audit_symbind will be responsible to setup the final relocation value; while for lazy binding _dl_fixup/_dl_profile_fixup will call the audit callback and tail cail elf_machine_fixup_plt (which will call sparc64_fixup_plt). This patch fixes by issuing the SPARC specific routine on bindnow and forwarding the audit value to elf_machine_fixup_plt for lazy resolution. It fixes the la_symbind for bind-now tests on sparc64 and sparcv9: elf/tst-audit24a elf/tst-audit24b elf/tst-audit24c elf/tst-audit24d Checked on sparc64-linux-gnu and sparcv9-linux-gnu. Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
* Fix misspellings in sysdeps/ -- BZ 25337Paul Pluzhnikov2023-05-301-2/+2
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* elf: Stop including tls.h in ldsodefs.hSergey Bugaev2023-04-101-1/+0
| | | | | | | Nothing in there needs tls.h Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> Message-Id: <20230319151017.531737-24-bugaevc@gmail.com>
* Remove --enable-tunables configure optionAdhemerval Zanella Netto2023-03-291-17/+3
| | | | | | | | | | | | And make always supported. The configure option was added on glibc 2.25 and some features require it (such as hwcap mask, huge pages support, and lock elisition tuning). It also simplifies the build permutations. Changes from v1: * Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs more discussion. * Cleanup more code. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* Update copyright dates with scripts/update-copyrightsJoseph Myers2023-01-061-1/+1
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* elf: Rework exception handling in the dynamic loader [BZ #25486]Florian Weimer2022-11-031-8/+4
| | | | | | | | | | | | | | | | | | | | | | | 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>
* elf: Introduce to _dl_call_finiFlorian Weimer2022-10-271-0/+8
| | | | | | | | | | This consolidates the destructor invocations from _dl_fini and dlclose. Remove the micro-optimization that avoids calling _dl_call_fini if they are no destructors (as dlclose is quite expensive anyway). The debug log message is now printed unconditionally. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ld.so: Export tls_init_tp_called as __rtld_tls_init_tp_calledFlorian Weimer2022-10-271-0/+3
| | | | | | | This allows the rest of dynamic loader to check whether the TCB has been set up (and THREAD_GETMEM and THREAD_SETMEM will work). Reviewed-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
* elf: Rename _dl_sort_maps parameter from skip to force_firstFlorian Weimer2022-09-061-2/+4
| | | | | | | The new implementation will not be able to skip an arbitrary number of objects. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Revert "Detect ld.so and libc.so version inconsistency during startup"Florian Weimer2022-08-251-4/+0
| | | | | | | | | | | | | | | | This reverts commit 6f85dbf102ad7982409ba0fe96886caeb6389fef. Once this change hits the release branches, it will require relinking of all statically linked applications before static dlopen works again, for the majority of updates on release branches: The NEWS file is regularly updated with bug references, so the __libc_early_init suffix changes, and static dlopen cannot find the function anymore. While this ABI check is still technically correct (we do require rebuilding & relinking after glibc updates to keep static dlopen working), it is too drastic for stable release branches. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Detect ld.so and libc.so version inconsistency during startupFlorian Weimer2022-08-241-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The files NEWS, include/link.h, and sysdeps/generic/ldsodefs.h contribute to the version fingerprint used for detection. The fingerprint can be further refined using the --with-extra-version-id configure argument. _dl_call_libc_early_init is replaced with _dl_lookup_libc_early_init. The new function is used store a pointer to libc.so's __libc_early_init function in the libc_map_early_init member of the ld.so namespace structure. This function pointer can then be called directly, so the separate invocation function is no longer needed. The versioned symbol lookup needs the symbol versioning data structures, so the initialization of libc_map and libc_map_early_init is now done from _dl_check_map_versions, after this information becomes available. (_dl_map_object_from_fd does not set this up in time, so the initialization code had to be moved from there.) This means that the separate initialization code can be removed from dl_main because _dl_check_map_versions covers all maps, including the initial executable loaded by the kernel. The lookup still happens before relocation and the invocation of IFUNC resolvers, so IFUNC resolvers are protected from ABI mismatch. The __libc_early_init function pointer is not protected because so little code runs between the pointer write and the invocation (only dynamic linker code and IFUNC resolvers). Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* elf: Remove ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATAFangrui Song2022-06-151-11/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | If an executable has copy relocations for extern protected data, that can only work if the library containing the definition is built with assumptions (a) the compiler emits GOT-generating relocations (b) the linker produces R_*_GLOB_DAT instead of R_*_RELATIVE. Otherwise the library uses its own definition directly and the executable accesses a stale copy. Note: the GOT relocations defeat the purpose of protected visibility as an optimization, but allow rtld to make the executable and library use the same copy when copy relocations are present, but it turns out this never worked perfectly. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA has strange semantics when both a.so and b.so define protected var and the executable copy relocates var: b.so accesses its own copy even with GLOB_DAT. The behavior change is from commit 62da1e3b00b51383ffa7efc89d8addda0502e107 (x86) and then copied to nios2 (ae5eae7cfc9c4a8297ff82ec6b794faca1976ecc) and arc (0e7d930c4c11de896fe807f67fa1eb756c9c1e05). Without ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA, b.so accesses the copy relocated data like a.so. There is now a warning for copy relocation on protected symbol since commit 7374c02b683b7110b853a32496a619410364d70b. It's extremely unlikely anyone relies on the ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA behavior, so let's remove it: this removes a check in the symbol lookup code.
* elf: Remove _dl_skip_argsAdhemerval Zanella2022-05-301-4/+0
| | | | | | Now that no architecture uses it anymore. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* rtld: Remove DL_ARGV_NOT_RELRO and make _dl_skip_args constSzabolcs Nagy2022-05-171-10/+3
| | | | | | | | | | | _dl_skip_args is always 0, so the target specific code that modifies argv after relro protection is applied is no longer used. After the patch relro protection is applied to _dl_argv consistently on all targets. Reviewed-by: Florian Weimer <fweimer@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Remove dl-librecon.h header.Adhemerval Zanella2022-05-161-3/+0
| | | | | | | | | | | | | | | | | | | | | | | The Linux version used by i686 and m68k provide three overrrides for generic code: 1. DISTINGUISH_LIB_VERSIONS to print additional information when libc5 is used by a dependency. 2. EXTRA_LD_ENVVARS to that enabled LD_LIBRARY_VERSION environment variable. 3. EXTRA_UNSECURE_ENVVARS to add two environment variables related to aout support. None are really requires, it has some decades since libc5 or aout suppported was removed and Linux even remove support for aout files. The LD_LIBRARY_VERSION is also dead code, dl_correct_cache_id is not used anywhere. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Remove kernel version checkAdhemerval Zanella2022-05-161-6/+0
| | | | | | | | | | | | | | | | | | | | The kernel version check is used to avoid glibc to run on older kernels where some syscall are not available and fallback code are not enabled to handle graciously fail. However, it does not prevent if the kernel does not correctly advertise its version through vDSO note, uname or procfs. Also kernel version checks are sometime not desirable by users, where they want to deploy on different system with different kernel version knowing the minimum set of syscall is always presented on such systems. The kernel version check has been removed along with the LD_ASSUME_KERNEL environment variable. The minimum kernel used to built glibc is still provided through NT_GNU_ABI_TAG ELF note and also printed when libc.so is issued. Checked on x86_64-linux-gnu.
* csu: Implement and use _dl_early_allocate during static startupFlorian Weimer2022-05-161-0/+5
| | | | | | | | | | | This implements mmap fallback for a brk failure during TLS allocation. scripts/tls-elf-edit.py is updated to support the new patching method. The script no longer requires that in the input object is of ET_DYN type. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Remove unused enum allowmaskFangrui Song2022-04-251-11/+0
| | | | | | | Unused since 52a01100ad011293197637e42b5be1a479a2f4ae ("elf: Remove ad-hoc restrictions on dlopen callers [BZ #22787]"). Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Remove _dl_skip_args_internal declarationSzabolcs Nagy2022-04-121-5/+0
| | | | | | It does not seem to be used. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Remove inline _dl_dprintfAdhemerval Zanella2022-03-231-11/+0
| | | | | | It is not used on rtld and ldsodef interfaces are meant to be used solely on loader. It also removes the only usage of gcc extension __builtin_va_arg_pack.
* elf: Remove LD_USE_LOAD_BIASAdhemerval Zanella2022-02-101-5/+0
| | | | | | | | It is solely for prelink with PIE executables [1]. [1] https://sourceware.org/legacy-ml/libc-hacker/2003-11/msg00127.html Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* elf: Remove prelink supportAdhemerval Zanella2022-02-101-11/+0
| | | | | | | | | | | | | Prelinked binaries and libraries still work, the dynamic tags DT_GNU_PRELINKED, DT_GNU_LIBLIST, DT_GNU_CONFLICT just ignored (meaning the process is reallocated as default). The loader environment variable TRACE_PRELINKING is also removed, since it used solely on prelink. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* elf: Issue la_symbind for bind-now (BZ #23734)Adhemerval Zanella2022-02-011-1/+4
| | | | | | | | | | | | | | | | | | | | | | | The audit symbind callback is not called for binaries built with -Wl,-z,now or when LD_BIND_NOW=1 is used, nor the PLT tracking callbacks (plt_enter and plt_exit) since this would change the expected program semantics (where no PLT is expected) and would have performance implications (such as for BZ#15533). LAV_CURRENT is also bumped to indicate the audit ABI change (where la_symbind flags are set by the loader to indicate no possible PLT trace). To handle powerpc64 ELFv1 function descriptor, _dl_audit_symbind requires to know whether bind-now is used so the symbol value is updated to function text segment instead of the OPD (for lazy binding this is done by PPC64_LOAD_FUNCPTR on _dl_runtime_resolve). Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, powerpc64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* elf: Fix initial-exec TLS access on audit modules (BZ #28096)Adhemerval Zanella2022-02-011-1/+1
| | | | | | | | | | | | | | | | | For audit modules and dependencies with initial-exec TLS, we can not set the initial TLS image on default loader initialization because it would already be set by the audit setup. However, subsequent thread creation would need to follow the default behaviour. This patch fixes it by setting l_auditing link_map field not only for the audit modules, but also for all its dependencies. This is used on _dl_allocate_tls_init to avoid the static TLS initialization at load time. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
* Update copyright dates with scripts/update-copyrightsPaul Eggert2022-01-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | 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 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
* elf: Add _dl_find_object functionFlorian Weimer2021-12-281-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* elf: Add _dl_audit_pltexitAdhemerval Zanella2021-12-281-0/+6
| | | | | | | | | It consolidates the code required to call la_pltexit audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_pltenterAdhemerval Zanella2021-12-281-0/+4
| | | | | | | | | It consolidates the code required to call la_pltenter audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_preinitAdhemerval Zanella2021-12-281-0/+3
| | | | | | | | | It consolidates the code required to call la_preinit audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_symbind_alt and _dl_audit_symbindAdhemerval Zanella2021-12-281-0/+10
| | | | | | | | | It consolidates the code required to call la_symbind{32,64} audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_objcloseAdhemerval Zanella2021-12-281-0/+4
| | | | | | | | | It consolidates the code required to call la_objclose audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_objsearchAdhemerval Zanella2021-12-281-0/+7
| | | | | | | | | It consolidates the code required to call la_objsearch audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_activity_map and _dl_audit_activity_nsidAdhemerval Zanella2021-12-281-0/+10
| | | | | | | | | | | | | It consolidates the code required to call la_activity audit callback. Also for a new Lmid_t the namespace link_map list are empty, so it requires to check if before using it. This can happen for when audit module is used along with dlmopen. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Add _dl_audit_objopenAdhemerval Zanella2021-12-281-0/+5
| | | | | | | | It consolidates the code required to call la_objopen audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* elf: Introduce GLRO (dl_libc_freeres), called from __libc_freeresFlorian Weimer2021-11-171-0/+7
| | | | | | | This will be used to deallocate memory allocated using the non-minimal malloc. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Fix e6fd79f379 build with --enable-tunables=noAdhemerval Zanella2021-10-211-0/+9
| | | | | | The _dl_sort_maps_init() is not defined when tunables is not enabled. Checked on x86_64-linux-gnu.
* elf: Fix slow DSO sorting behavior in dynamic loader (BZ #17645)Chung-Lin Tang2021-10-211-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This second patch contains the actual implementation of a new sorting algorithm for shared objects in the dynamic loader, which solves the slow behavior that the current "old" algorithm falls into when the DSO set contains circular dependencies. The new algorithm implemented here is simply depth-first search (DFS) to obtain the Reverse-Post Order (RPO) sequence, a topological sort. A new l_visited:1 bitfield is added to struct link_map to more elegantly facilitate such a search. The DFS algorithm is applied to the input maps[nmap-1] backwards towards maps[0]. This has the effect of a more "shallow" recursion depth in general since the input is in BFS. Also, when combined with the natural order of processing l_initfini[] at each node, this creates a resulting output sorting closer to the intuitive "left-to-right" order in most cases. Another notable implementation adjustment related to this _dl_sort_maps change is the removing of two char arrays 'used' and 'done' in _dl_close_worker to represent two per-map attributes. This has been changed to simply use two new bit-fields l_map_used:1, l_map_done:1 added to struct link_map. This also allows discarding the clunky 'used' array sorting that _dl_sort_maps had to sometimes do along the way. Tunable support for switching between different sorting algorithms at runtime is also added. A new tunable 'glibc.rtld.dynamic_sort' with current valid values 1 (old algorithm) and 2 (new DFS algorithm) has been added. At time of commit of this patch, the default setting is 1 (old algorithm). Signed-off-by: Chung-Lin Tang <cltang@codesourcery.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ld.so: Initialize bootstrap_map.l_ld_readonly [BZ #28340]H.J. Lu2021-10-191-0/+10
| | | | | | | | | | | | | | | 1. Define DL_RO_DYN_SECTION to initalize bootstrap_map.l_ld_readonly before calling elf_get_dynamic_info to get dynamic info in bootstrap_map, 2. Define a single static inline bool dl_relocate_ld (const struct link_map *l) { /* Don't relocate dynamic section if it is readonly */ return !(l->l_ld_readonly || DL_RO_DYN_SECTION); } This updates BZ #28340 fix.
* elf: Avoid deadlock between pthread_create and ctors [BZ #28357]Szabolcs Nagy2021-10-041-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The fix for bug 19329 caused a regression such that pthread_create can deadlock when concurrent ctors from dlopen are waiting for it to finish. Use a new GL(dl_load_tls_lock) in pthread_create that is not taken around ctors in dlopen. The new lock is also used in __tls_get_addr instead of GL(dl_load_lock). The new lock is held in _dl_open_worker and _dl_close_worker around most of the logic before/after the init/fini routines. When init/fini routines are running then TLS is in a consistent, usable state. In _dl_open_worker the new lock requires catching and reraising dlopen failures that happen in the critical section. The new lock is reinitialized in a fork child, to keep the existing behaviour and it is kept recursive in case malloc interposition or TLS access from signal handlers can retake it. It is not obvious if this is necessary or helps, but avoids changing the preexisting behaviour. The new lock may be more appropriate for dl_iterate_phdr too than GL(dl_load_write_lock), since TLS state of an incompletely loaded module may be accessed. If the new lock can replace the old one, that can be a separate change. Fixes bug 28357. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]H.J. Lu2021-09-221-5/+2
| | | | | | | | | | | | | | | | | We can't relocate entries in dynamic section if it is readonly: 1. Add a l_ld_readonly field to struct link_map to indicate if dynamic section is readonly and set it based on p_flags of PT_DYNAMIC segment. 2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic section should be relocated. 3. Remove DL_RO_DYN_TEMP_CNT. 4. Don't use a static dynamic section to make readonly dynamic section in vDSO writable. 5. Remove the temp argument from elf_get_dynamic_info. This fixes BZ #28340. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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