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2021-05-07misc: use _fitoa_word to implement __fd_to_filename.Érico Nogueira
In a default build for x86_64, size decreased by 24 bytes: 1883294 to 1883270. Aditionally, avoids repeating the number printing logic in multiple places. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-05-06Annotate additional APIs with GCC attribute access.Martin Sebor
This change continues the improvements to compile-time out of bounds checking by decorating more APIs with either attribute access, or by explicitly providing the array bound in APIs such as tmpnam() that expect arrays of some minimum size as arguments. (The latter feature is new in GCC 11.) The only effects of the attribute and/or the array bound is to check and diagnose calls to the functions that fail to provide a sufficient number of elements, and the definitions of the functions that access elements outside the specified bounds. (There is no interplay with _FORTIFY_SOURCE here yet.) Tested with GCC 7 through 11 on x86_64-linux.
2021-05-05nptl: Move sem_close, sem_open into libcFlorian Weimer
The symbols were moved using move-symbol-to-libc.py. Both functions are moved at the same time because they depend on internal functions in sysdeps/pthread/sem_routines.c, which are moved in this commit as well. Additional hidden prototypes are required to avoid check-localplt failures. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-04-27Add __attribute_access_none to disable GCC warnings [BZ #27714]Martin Sebor
GCC 11 warns when a pointer to an uninitialized object is passed to a function that takes a const-qualified argument. This is done on the assumption that most such functions read from the object. For the rare case of a function that doesn't, GCC 11 extends attribute access to add a new mode called none. POSIX pthread_setspecific() is one such rare function that takes a const void* argument but that doesn't read from the object it points to. To suppress the -Wmaybe-uninitialized issued by GCC 11 when the address of an uninitialized object is passed to it (e.g., the result of malloc()), this change #defines __attr_access_none in cdefs.h and uses the macro on the function in sysdeps/htl/pthread.h and sysdeps/nptl/pthread.h.
2021-04-21nptl: Move pthread_setcancelstate into libcFlorian Weimer
No new symbol version is required because there was a forwarder. The symbol has been moved using scripts/move-symbol-to-libc.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-04-15misc: syslog: Use static const for AF_UNIX addressAdhemerval Zanella
Checked on x86_64-linux-gnu.
2021-04-15misc: syslog: Use CLOC_EXEC with _PATH_CONSOLE (BZ #17145)Adhemerval Zanella
The syslog open the '/dev/console' for LOG_CONS without O_CLOEXEC, which might leak in multithread programs that call fork. Checked on x86_64-linux-gnu.
2021-04-15misc: syslog: Assume MSG_NOSIGNAL support (BZ #17144)Adhemerval Zanella
MSG_NOSIGNAL was added on POSIX 2008 and Hurd seems to support it. The SIGPIPE handling also makes the implementation not thread-safe (due the sigaction usage). Checked on x86_64-linux-gnu.
2021-04-15misc: syslog: Use bool for connectedAdhemerval Zanella
Checked on x86_64-linux-gnu.
2021-04-13misc: syslog: Fix calls to openlog() with LOG_KERN facility (BZ #3604)Dan Raymond
POSIX states for syslog [1]: "Values of the priority argument are formed by OR'ing together a severity-level value and an optional facility value. If no facility value is specified, the current default facility value is used." So the patch fixes an existing violation of the openlog interface contract where it is ignoring the facility argument when the value is zero It allows the use LOG_KERN by calling openlog prior syslog usage. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> [1] https://pubs.opengroup.org/onlinepubs/9699919799/functions/syslog.html
2021-04-12linux: always update select timeout (BZ #27706)Adhemerval Zanella
The timeout should be updated even on failure for time64 support. Checked on i686-linux-gnu.
2021-04-12linux: Normalize and return timeout on select (BZ #27651)Adhemerval Zanella
The commit 2433d39b697, which added time64 support to select, changed the function to use __NR_pselect6 (or __NR_pelect6_time64) on all architectures. However, on architectures where the symbol was implemented with __NR_select the kernel normalizes the passed timeout instead of return EINVAL. For instance, the input timeval { 0, 5000000 } is interpreted as { 5, 0 }. And as indicated by BZ #27651, this semantic seems to be expected and changing it results in some performance issues (most likely the program does not check the return code and keeps issuing select with unormalized tv_usec argument). To avoid a different semantic depending whether which syscall the architecture used to issue, select now always normalize the timeout input. This is a slight change for some ABIs (for instance aarch64). Checked on x86_64-linux-gnu and i686-linux-gnu.
2021-03-26misc: Fix tst-select timeout handling (BZ#27648)Adhemerval Zanella
Instead of polling the stderr, create two pipes and fork to check if child timeout as expected similar to tst-pselect.c. Also lower the timeout value. Checked on x86_64-linux-gnu.
2021-03-23tst: Provide test for selectLukasz Majewski
This change adds new test to assess select()'s timeout related functionality (the rdfs set provides valid fd - stderr - but during normal program operation there is no data to be read, so one just waits for timeout). To be more specific - two use cases are checked: - if select() times out immediately when passed struct timeval has zero values of tv_usec and tv_sec. - if select() times out after timeout specified in passed argument Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-01Implement <unwind-link.h> for dynamically loading the libgcc_s unwinderFlorian Weimer
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>
2021-02-09misc: Sync cdefs.h with gnulibAdhemerval Zanella
It adds __glibc_has_builtin, __glibc_has_extension, and __attribute_maybe_unused__ alongsize with some fixes. The differences are: --- glibc +++ gnulib @@ -259,7 +259,9 @@ # define __attribute_const__ /* Ignore */ #endif -#if __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__) +#if defined __STDC_VERSION__ && 201710L < __STDC_VERSION__ +# define __attribute_maybe_unused__ [[__maybe_unused__]] +#elif __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__) # define __attribute_maybe_unused__ __attribute__ ((__unused__)) #else # define __attribute_maybe_unused__ /* Ignore */ @@ -485,7 +487,7 @@ /* The #ifndef lets Gnulib avoid including these on non-glibc platforms, where the includes typically do not exist. */ -#ifdef __GLIBC__ +#ifndef __WORDSIZE # include <bits/wordsize.h> # include <bits/long-double.h> #endif The [[__attribute_maybe_unused__]] attribute removal __ is due Joseph questioning gcc support with -std=c2x or -std=gnu2x [1]. The _WORDSIZE replacement by __GLIBC__ is because it does not play well with internal cdefs.h that also uses __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI. Checked on x86_64-linux-gnu. [1] https://sourceware.org/pipermail/libc-alpha/2021-January/121600.html
2021-01-21Use hidden visibility for early static PIE codeSzabolcs Nagy
Extern symbol access in position independent code usually involves GOT indirection which needs RELATIVE reloc in a static linked PIE. (On some targets this is avoided e.g. because the linker can relax a GOT access to a pc-relative access, but this is not generally true.) Code that runs before static PIE self relocation must avoid relying on dynamic relocations which can be ensured by using hidden visibility. However we cannot just make all symbols hidden: On i386, all calls to IFUNC functions must go through PLT and calls to hidden functions CANNOT go through PLT in PIE since EBX used in PIE PLT may not be set up for local calls to hidden IFUNC functions. This patch aims to make symbol references hidden in code that is used before and by _dl_relocate_static_pie when building a static PIE libc. Note: for an object that is used in the startup code, its references and definition may not have consistent visibility: it is only forced hidden in the startup code. This is needed for fixing bug 27072. Co-authored-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-01-08mntent: Use __putc_unlocked instead of fputc_unlockedSiddhesh Poyarekar
__putc_unlocked is guaranteed to be inlined all the time as opposed to fputc_unlocked, which does not get inlined when glibc is built with -Os. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-01-02Update copyright dates with scripts/update-copyrightsPaul Eggert
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
2020-12-31Introduce _FORTIFY_SOURCE=3Siddhesh Poyarekar
Introduce a new _FORTIFY_SOURCE level of 3 to enable additional fortifications that may have a noticeable performance impact, allowing more fortification coverage at the cost of some performance. With llvm 9.0 or later, this will replace the use of __builtin_object_size with __builtin_dynamic_object_size. __builtin_dynamic_object_size ----------------------------- __builtin_dynamic_object_size is an LLVM builtin that is similar to __builtin_object_size. In addition to what __builtin_object_size does, i.e. replace the builtin call with a constant object size, __builtin_dynamic_object_size will replace the call site with an expression that evaluates to the object size, thus expanding its applicability. In practice, __builtin_dynamic_object_size evaluates these expressions through malloc/calloc calls that it can associate with the object being evaluated. A simple motivating example is below; -D_FORTIFY_SOURCE=2 would miss this and emit memcpy, but -D_FORTIFY_SOURCE=3 with the help of __builtin_dynamic_object_size is able to emit __memcpy_chk with the allocation size expression passed into the function: void *copy_obj (const void *src, size_t alloc, size_t copysize) { void *obj = malloc (alloc); memcpy (obj, src, copysize); return obj; } Limitations ----------- If the object was allocated elsewhere that the compiler cannot see, or if it was allocated in the function with a function that the compiler does not recognize as an allocator then __builtin_dynamic_object_size also returns -1. Further, the expression used to compute object size may be non-trivial and may potentially incur a noticeable performance impact. These fortifications are hence enabled at a new _FORTIFY_SOURCE level to allow developers to make a choice on the tradeoff according to their environment.
2020-12-23misc: Use __ferror_unlocked instead of ferrorSiddhesh Poyarekar
The ferror results in an unnecessary PLT reference. Use __ferror_unlocked instead , which gets inlined.
2020-12-22addmntent: Remove unbounded alloca usage from getmntent [BZ#27083]Siddhesh Poyarekar
The addmntent function replicates elements of struct mnt on stack using alloca, which is unsafe. Put characters directly into the stream, escaping them as they're being written out. Also add a test to check all escaped characters with addmntent and getmntent.
2020-12-16Replace __libc_multiple_libcs with __libc_initial flagFlorian Weimer
Change sbrk to fail for !__libc_initial (in the generic implementation). As a result, sbrk is (relatively) safe to use for the __libc_initial case (from the main libc). It is therefore no longer necessary to avoid using it in that case (or updating the brk cache), and the __libc_initial flag does not need to be updated as part of dlmopen or static dlopen. As before, direct brk system calls on Linux may lead to memory corruption. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2020-12-12Fix spelling and grammar in several commentsJonny Grant
2020-12-11treewide: fix incorrect spelling of indices in commentsDmitry V. Levin
Replace 'indeces' with 'indices', the most annoying of these typos were those found in elf.h which is a public header file copied to other projects.
2020-11-13Remove tls.h inclusion from internal errno.hAdhemerval Zanella
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.
2020-11-05Remove __warndeclSiddhesh Poyarekar
The macro is not used anymore, so remove it and warning-nop.c. Reviewed-by: Florian Weimer <fweimer@redhat.com>
2020-10-30Avoid -Wstringop-overflow warning in pthread_cleanup_push macrosJoseph Myers
GCC 11 introduces a -Wstringop-overflow warning for calls to functions with an array argument passed as a pointer to memory not large enough for that array. This includes the __sigsetjmp calls from pthread_cleanup_push macros, because those use a structure in __pthread_unwind_buf_t, which has a common initial subsequence with jmp_buf but does not include the saved signal mask; this is OK in this case because the second argument to __sigsetjmp is 0 so the signal mask is not accessed. To avoid this warning, use a function alias __sigsetjmp_cancel with first argument an array of exactly the type used in the calls to the function, if using GCC 11 or later. With older compilers, continue to use __sigsetjmp with a cast, to avoid any issues with compilers predating the returns_twice attribute not applying the same special handling to __sigsetjmp_cancel as to __sigsetjmp. Tested with build-many-glibcs.py for arm-linux-gnueabi that this fixes the testsuite build failures.
2020-10-27misc: Add internal __getauxval2 functionFlorian Weimer
The explicit error return value (without in-band signaling) avoids complicated steps to detect errors based on whether errno has been updated. Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-09-22Define __THROW to noexcept for C++11 and laterJonathan Wakely
The __THROW macro and friends expand to "throw ()" for C++ code, but that syntax is deprecated in C++11 and no longer supported at all since C++20. In order for glibc headers to be compatible with C++20, "noexcept" should be used instead. This patch uses "noexcept (true)" rather than just "noexcept", which is semantically equivalent, but avoids any possibility of parsing ambiguities if the next preprocessor token happens to be an opening parenthesis. This is probably unnecessary, but it seems safer to be cautious.
2020-09-11Remove internal usage of extensible stat functionsAdhemerval Zanella
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>
2020-08-18Correct locking and cancellation cleanup in syslog functions (bug 26100)Andreas Schwab
Properly serialize the access to the global state shared between the syslog functions, to avoid races in multithreaded processes. Protect a local allocation in the __vsyslog_internal function from leaking during cancellation.
2020-07-06Add the __libc_single_threaded variableFlorian Weimer
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>
2020-05-04improve out-of-bounds checking with GCC 10 attribute access [BZ #25219]Martin Sebor
Adds the access attribute newly introduced in GCC 10 to the subset of function declarations that are already covered by _FORTIFY_SOURCE and that don't have corresponding GCC built-in equivalents. Reviewed-by: DJ Delorie <dj@redhat.com>
2020-04-30Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABIPaul E. Murphy
Improve the commentary to aid future developers who will stumble upon this novel, yet not always perfect, mechanism to support alternative formats for long double. Likewise, rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI now that development work has settled down. The command used was git grep -l __LONG_DOUBLE_USES_FLOAT128 ':!./ChangeLog*' | \ xargs sed -i 's/__LONG_DOUBLE_USES_FLOAT128/__LDOUBLE_REDIRECTS_TO_FLOAT128_ABI/g' Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
2020-04-28misc: Remove sstk from the autogenerated system call listFlorian Weimer
This change should not have an effect because the system call was never defined. Also add the misssing attribute_compat_text_section attribute to the sstk function (a minor optimization). Also update the NEWS file to document the change. Fixes commit 9cc93ba0973ad04ee26c515a1552afb85e73c6ba ("misc: Turn sstk into a compat symbol").
2020-04-27misc: Turn sstk into a compat symbolFlorian Weimer
It is not implemented anywhere. There is an osf_sstk system call on alpha, but it is not used to implement sstk, and the system call is not implemented on Linux, either.
2020-04-22Add a syscall test for [BZ #25810]H.J. Lu
Add a test to pass 64-bit long arguments to syscall with undefined upper 32 bits on x32. Tested on i386, x86-64 and x32 as well as with build-many-glibcs.py.
2020-02-18<fd_to_filename.h>: Add type safety and port to HurdFlorian Weimer
The new type struct fd_to_filename makes the allocation of the backing storage explicit. Hurd uses /dev/fd, not /proc/self/fd. Co-Authored-By: Paul Eggert <eggert@cs.ucla.edu>
2020-02-17Prepare redirections for IEEE long double on powerpc64leGabriel F. T. Gomes
All functions that have a format string, which can consume a long double argument, must have one version for each long double format supported on a platform. On powerpc64le, these functions currently have two versions (i.e.: long double with the same format as double, and long double with IBM Extended Precision format). Support for a third long double format option (i.e. long double with IEEE long double format) is being prepared and all the aforementioned functions now have a third version (not yet exported on the master branch, but the code is in). For these functions to get selected (during build time), references to them in user programs (or dependent libraries) must get redirected to the aforementioned new versions of the functions. This patch installs the header magic required to perform such redirections. Notice, however, that since the redirections only happen when __LONG_DOUBLE_USES_FLOAT128 is set to 1, and no platform (including powerpc64le) currently does it, no redirections actually happen. Redirections and the exporting of the new functions will happen at the same time (when powerpc64le adds ldbl-128ibm-compat to their Implies. Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com> Reviewed-by: Paul E. Murphy <murphyp@linux.vnet.ibm.com>
2020-01-01Update copyright dates with scripts/update-copyrights.Joseph Myers
2019-12-23ldbl-128ibm-compat: Add *cvt functionsGabriel F. T. Gomes
This patch adds IEEE long double versions of q*cvt* functions for powerpc64le. Unlike all other long double to/from string conversion functions, these do not rely on internal functions that can take floating-point numbers with different formats and act on them accordingly, instead, the related files are rebuilt with the -mabi=ieeelongdouble compiler flag set. Having -mabi=ieeelongdouble passed to the compiler causes the object files to be marked with a .gnu_attribute that is incompatible with the .gnu_attribute in files built with -mabi=ibmlongdouble (the default). The difference causes error messages similar to the following: ld: libc_pic.a(s_isinfl.os) uses IBM long double, libc_pic.a(ieee128-qefgcvt_r.os) uses IEEE long double. collect2: error: ld returned 1 exit status make[2]: *** [../Makerules:649: libc_pic.os] Error 1 Although this warning is useful in other situations, the library actually needs to have functions with different long double formats, so .gnu_attribute generation is explicitly disabled for these files with the use of -mno-gnu-attribute. Tested for powerpc64le on the branch that actually enables the sysdeps/ieee754/ldbl-128ibm-compat for powerpc64le. Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
2019-12-23Refactor *cvt functions implementation (2/2)Gabriel F. T. Gomes
This patch refactors the *cvt functions implementation in a way that makes it easier to re-use them for implementing the IEEE long double on powerpc64le. By removing the macros that generate the function names (APPEND combined with FUNC_PREFIX), the new code makes it easier to define new function names, such as __qecvtieee128. Tested that installed stripped binaries for all build-many-glibcs targets remain identical before and after this patch. Also tested for powerpc64le and x86_64. Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
2019-12-23Refactor *cvt functions implementation (1/2)Gabriel F. T. Gomes
This patch refactors the *cvt functions implementation in a way that makes it easier to re-use them for implementing the IEEE long double on powerpc64le. By splitting the implementation per se in one file (efgcvt-template.c) and the alias definitions in others (e.g. efgcvt.c), the new code makes it easier to define new function names, such as __qecvtieee128. Tested that installed stripped binaries for all build-many-glibcs targets remain identical before and after this patch. Also tested for powerpc64le and x86_64. Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
2019-11-22misc: Set generic pselect as ENOSYSAdhemerval Zanella
The generic pselect implementation has the very specific race condition that motived the creation of the pselect syscall (no atomicity in signal mask set/reset). Using it as generic implementation is counterproductive Also currently only microblaze uses it as fallback when used on kernel prior 3.15. This patch moves the generic implementation to a microblaze specific one, sets the generic internal as a ENOSYS, and cleanups the Linux generic implementation. The microblaze implementation mimics the previous Linux generic one, where it either uses pselect6 directly if __ASSUME_PSELECT or a first try pselect6 then the fallback otherwise. Checked on x86_64-linux-gnu and microblaze-linux-gnu.
2019-11-21Don't use a custom wrapper macro around __has_include (bug 25189).Emilio Cobos Álvarez
This causes issues when using clang with -frewrite-includes to e.g., submit the translation unit to a distributed compiler. In my case, I was building Firefox using sccache. See [1] for a reduced test-case since I initially thought this was a clang bug, and [2] for more context. Apparently doing this is invalid C++ per [cpp.cond], which mentions [3]: > The #ifdef and #ifndef directives, and the defined conditional > inclusion operator, shall treat __has_include and __has_cpp_attribute > as if they were the names of defined macros. The identifiers > __has_include and __has_cpp_attribute shall not appear in any context > not mentioned in this subclause. [1]: https://bugs.llvm.org/show_bug.cgi?id=43982 [2]: https://bugs.llvm.org/show_bug.cgi?id=37990 [3]: http://eel.is/c++draft/cpp.cond#7.sentence-2 Change-Id: Id4b8ee19176a9e4624b533087ba870c418f27e60
2019-10-30Change most internal uses of time to __clock_gettime.Adhemerval Zanella
As for gettimeofday, time will be implemented based on clock_gettime on all platforms and internal code should use clock_gettime directly. In addition to removing a layer of indirection, this will allow us to remove the PLT-bypass gunk for gettimeofday. The changed code always assumes __clock_gettime (CLOCK_REALTIME) or __clock_gettime (CLOCK_REALTIME_COARSE) (for Linux case) cannot fail, using the same rationale for gettimeofday change. And internal helper was added (time_now). Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, powerpc64-linux-gnu, and powerpc-linux-gnu. Reviewed-by: Lukasz Majewski <lukma@denx.de>
2019-09-07Prefer https to http for gnu.org and fsf.org URLsPaul Eggert
Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-02Add misc/tst-mntent-autofs, testing autofs "ignore" filteringFlorian Weimer
2019-09-02Use autofs "ignore" mount hint in getmntent_r/getmntentIan Kent
Historically autofs mounts were not included in mount table listings. This is the case in other SysV autofs implementations and was also the case with Linux autofs. But now that /etc/mtab is a symlink to the proc filesystem mount table the autofs mount entries appear in the mount table on Linux. Prior to the symlinking of /etc/mtab mount table it was sufficient to call mount(2) and simply not update /etc/mtab to exclude autofs mounts from mount listings. Also, with the symlinking of /etc/mtab we have seen a shift in usage toward using the proc mount tables directly. But the autofs mount entries need to be retained when coming from the proc file system for applications that need them (largely autofs file system users themselves) so filtering out these entries within the kernel itself can't be done. So it needs be done in user space. There are three reasons to omit the autofs mount entries. One is that certain types of auto-mounts have an autofs mount for every entry in their autofs mount map and these maps can be quite large. This leads to mount table listings containing a lot of unnecessary entries. Also, this change in behaviour between autofs implementations can cause problems for applications that use getmntent(3) in other OS implementations as well as Linux. Lastly, there's very little that user space can do with autofs mount entries since this must be left to the autofs mount owner, typically the automount daemon. But it can also lead to attempts to access automount managed paths resulting mounts being triggered when they aren't needed or mounts staying mounted for much longer thay they need be. While the point of this change ins't to help with these problems (and it can be quite a problem) it may be a welcome side effect. So the Linux autofs file system has been modified to accept a pseudo mount option of "ignore" (as is used in other OS implementations) so that user space can use this as a hint to skip autofs entries on reading the mount table. The Linux autofs automount daemon used getmntent(3) itself and has been modified to use the proc file system directly so that it can "ignore" mount option. The use of this mount option is opt-in and a configuration option has been added which defaults to not use this option so if there are applications that need these entries, other than autofs itself, they can be retained. Also, since this filtering is based on an added mount option earlier versions of Linux autofs iand other autofs file system users will not use the option and so won't be affected by the change.