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2014-08-17make pointers used in robust list volatileRich Felker4-11/+18
when manipulating the robust list, the order of stores matters, because the code may be asynchronously interrupted by a fatal signal and the kernel will then access the robust list in what is essentially an async-signal context. previously, aliasing considerations made it seem unlikely that a compiler could reorder the stores, but proving that they could not be reordered incorrectly would have been extremely difficult. instead I've opted to make all the pointers used as part of the robust list, including those in the robust list head and in the individual mutexes, volatile. in addition, the format of the robust list has been changed to point back to the head at the end, rather than ending with a null pointer. this is to match the documented kernel robust list ABI. the null pointer, which was previously used, only worked because faults during access terminate the robust list processing.
2014-08-16fix robust mutex unrecoverable status, and related clean-upRich Felker3-12/+4
a robust mutex should not enter the unrecoverable status until it's unlocked without marking it consistent. previously, flag 8 in the type was used as an indication of unrecoverable, but only honored after successful locking; this resulted in a race window where the unrecoverable mutex could appear to a second thread as locked/busy again while the first thread was in the process of observing it as unrecoverable. now, flag 8 is used to mean that the mutex is in the process of being recovered, but not yet marked consistent. the flag only takes effect in pthread_mutex_unlock, where it causes the value 0x40000000 (owner dead flag, with old owner tid 0, an otherwise impossible state) to be stored in the lock. subsequent lock attempts will interpret this state as unrecoverable.
2014-08-16fix false ownership of mutexes due to tid reuse, using robust listRich Felker4-23/+26
per the resolution of Austin Group issue 755, the POSIX requirement that ownership be enforced for recursive and error-checking mutexes does not allow a random new thread to acquire ownership of an orphaned mutex just because it happened to be assigned the same tid as the original owner that exited with the mutex locked. one possible fix for this issue would be to disallow the kernel thread to terminate when it exited with mutexes held, permanently reserving the tid against reuse. however, this does not solve the problem for process-shared mutexes where lifetime cannot be controlled, so it was not used. the alternate approach I've taken is to reuse the robust mutex system for non-robust recursive and error-checking mutexes. when a thread exits, the kernel (or the new userspace robust-list code added in commit b092f1c5fa9c048e12d002c7b972df5ecbe96d1d) will set the owner-died bit for these orphaned mutexes, but since the mutex-type is not robust, pthread_mutex_trylock will not allow a new owner to acquire them. instead, they remain in a state of being permanently locked, as desired.
2014-08-16optimize locking against vm changes for mmap/munmapRich Felker2-8/+7
the whole point of this locking is to prevent munmap, or mmap with MAP_FIXED, from deallocating virtual addresses, or changing the backing a given virtual address refers to, during certain race windows involving self-synchronized unmapping or destruction of pthread synchronization objects. there is no need for exclusion in the other direction, so it suffices to take the lock momentarily and release it before making the syscall, rather than holding it across the syscall.
2014-08-16enable private futex for process-local robust mutexesRich Felker3-1/+25
the kernel always uses non-private wake when walking the robust list when a thread or process exits, so it's not able to wake waiters listening with the private futex flag. this problem is solved by doing the equivalent in userspace as the last step of pthread_exit. care is taken to remove mutexes from the robust list before unlocking them so that the kernel will not attempt to access them again, possibly after another thread locks them. this removal code can treat the list as singly-linked, since no further code which would add or remove items is able to run at this point. moreover, the pending pointer is not needed since the mutexes being unlocked are all process-local; in the case of asynchronous process termination, they all cease to exist. since a process-local robust mutex cannot come into existence without a call to pthread_mutexattr_setrobust in the same process, the code for userspace robust list processing is put in that source file, and a weak alias to a dummy function is used to avoid pulling in this bloat as part of pthread_exit in static-linked programs.
2014-08-15make futex operations use private-futex mode when possibleRich Felker23-66/+82
private-futex uses the virtual address of the futex int directly as the hash key rather than requiring the kernel to resolve the address to an underlying backing for the mapping in which it lies. for certain usage patterns it improves performance significantly. in many places, the code using futex __wake and __wait operations was already passing a correct fixed zero or nonzero flag for the priv argument, so no change was needed at the site of the call, only in the __wake and __wait functions themselves. in other places, especially where the process-shared attribute for a synchronization object was not previously tracked, additional new code is needed. for mutexes, the only place to store the flag is in the type field, so additional bit masking logic is needed for accessing the type. for non-process-shared condition variable broadcasts, the futex requeue operation is unable to requeue from a private futex to a process-shared one in the mutex structure, so requeue is simply disabled in this case by waking all waiters. for robust mutexes, the kernel always performs a non-private wake when the owner dies. in order not to introduce a behavioral regression in non-process-shared robust mutexes (when the owning thread dies), they are simply forced to be treated as process-shared for now, giving correct behavior at the expense of performance. this can be fixed by adding explicit code to pthread_exit to do the right thing for non-shared robust mutexes in userspace rather than relying on the kernel to do it, and will be fixed in this way later. since not all supported kernels have private futex support, the new code detects EINVAL from the futex syscall and falls back to making the call without the private flag. no attempt to cache the result is made; caching it and using the cached value efficiently is somewhat difficult, and not worth the complexity when the benefits would be seen only on ancient kernels which have numerous other limitations and bugs anyway.
2014-08-13fix #ifdef inside a macro argument list in __init_tls.cSzabolcs Nagy1-4/+3
C99 6.10.3p11 disallows such constructs so use an #ifdef outside of the argument list of __syscall
2014-08-13add inline isspace in ctype.h as an optimizationSzabolcs Nagy2-8/+1
isspace can be a bottleneck in a simple parser, inlining it gives slightly smaller and faster code src/locale/pleval.o already had this optimization, the size change for other libc functions for i386 is src/internal/intscan.o 2134 2118 -16 src/locale/dcngettext.o 1562 1552 -10 src/network/res_msend.o 1961 1940 -21 src/network/lookup_name.o 2627 2608 -19 src/network/getnameinfo.o 1814 1811 -3 src/network/lookup_serv.o 643 624 -19 src/stdio/vfscanf.o 2675 2663 -12 src/stdlib/atoll.o 117 107 -10 src/stdlib/atoi.o 95 91 -4 src/stdlib/atol.o 95 91 -4 src/time/strptime.o 1515 1503 -12 (TOTALS) 432451 432321 -130
2014-08-08add dlerror message for static-linked dlsym failureRich Felker1-0/+2
2014-08-08fix dlerror when using dlopen with a static libcClément Vasseur1-0/+2
when the dynamic loader is disabled, dlopen fails correctly but dlerror did not return a human readable error string like it should have.
2014-08-08make endmntent function handle null argumentTimo Teräs1-1/+1
The function originates from SunOS 4.x in which the null argument is allowed. glibc also handles this case.
2014-07-31harden locale name handling and prevent slashes in LC_MESSAGESRich Felker1-3/+3
the code which loads locale files was already rejecting locale names containing slashes. however, LC_MESSAGES records a locale name even if libc does not have a matching locale file, so that gettext or application code can use the recorded locale name for message translations to languages that libc does not support. this recorded name was not being checked for slashes, meaning that such code could potentially be tricked into directory traversal. in addition, since the value of a locale category is sometimes used as a pathname component by callers, the improved code rejects any value beginning with a dot. this prevents traversal to the parent directory via "..", use of the top-level locale directory via ".", and also avoids "hidden" directories as a side effect. finally, overly long locale names are now rejected (treated as an unrecognized name and thus as an alias for C.UTF-8) rather than being truncated.
2014-07-31implement ffsl and ffsll functionsRich Felker2-0/+14
per the resolution of Austin Group issue #617, these are accepted for XSI option in POSIX future and thus I'm treating them as standard functions.
2014-07-30add framework for mmap2 syscall unit to vary by archRich Felker2-2/+7
2014-07-30plural rule evaluator rewrite for dcngettextSzabolcs Nagy1-128/+106
using an operator precedence parser the code size became smaller and it is only slower by about %10 size of old vs new pleval.o on different archs: (with inlined isspace added to pleval.c for now) old: text data bss dec hex filename 828 0 0 828 33c pl.i386.o 1152 0 0 1152 480 pl.arm.o 1704 0 0 1704 6a8 pl.mips.o 1328 0 0 1328 530 pl.ppc.o 992 0 0 992 3e0 pl.x64.o new: text data bss dec hex filename 693 0 0 693 2b5 pl.i386.o 972 0 0 972 3cc pl.arm.o 1276 0 0 1276 4fc pl.mips.o 1087 0 0 1087 43f pl.ppc.o 846 0 0 846 34e pl.x64.o
2014-07-29reimplement if_nameindex and getifaddrs using netlinkTimo Teräs4-184/+411
the previous implementations had several deficiencies, the most severe of which was the inability to report unconfigured interfaces or interfaces without ipv4 addresses. among the options discussed for fixing this, using netlink turned out to be the one with the least cost and most additional advantages. other improvements include: if_nameindex now avoids duplicates in the list it produces, but still includes legacy-style interface aliases if any are in use. getifaddrs now reports hardware addresses and includes the scope_id for link-local ipv6 addresses in the resulting address.
2014-07-29tweaks to plural rules evaluatorSzabolcs Nagy1-54/+44
const parsing, depth accounting and failure handling was changed a bit so the generated code is slightly smaller.
2014-07-29harden dcngettext plural processingRich Felker1-2/+3
while the __mo_lookup backend can verify that the translated message ends with a null terminator, is has no way to know nplurals and thus no way to verify that sufficiently many null terminators are present in the string to satisfy all plural forms. the code in dcngettext was already attempting to avoid reading past the end of the mo file mapping, but failed to do so because the strlen call itself could over-read. using strnlen instead allows us to avoid the problem.
2014-07-29harden mo file processing for locale/translationsRich Felker1-2/+6
rather than just checking that the start of the string lies within the mapping, also check that the nominal length remains within the mapping, and that the null terminator is present at the nominal length. this ensures that the caller, using the result as a C string, will not read past the end of the mapping. the nominal length is never exposed to the caller, but it's useful internally to find where the null terminator should be without having to restort to linear search via strnlen/memchr.
2014-07-28implement non-default plural rules for ngettext translationsRich Felker2-8/+243
the new code in dcngettext was written by me, and the expression evaluator by Szabolcs Nagy (nsz).
2014-07-27implement gettext message translation functionsRich Felker4-68/+271
this commit replaces the stub implementations with working message translation functions. translation units are factored so as to prevent pulling in the legacy, non-library-safe functions which use a global textdomain in modern code which is using the versions with an explicit domain argument. bind_textdomain_codeset is also placed in its own file since it should not be needed by most programs. this implementation is still missing some features: the LANGUAGE environment variable (for multiple fallback languages) is not honored, and non-default plural-form rules are not supported. these issues will be addressed in a later commit. one notable difference from the GNU implementation is that there is no default path for loading translation files. in principle one could be added, but since the documented correct usage is to call the bindtextdomain function, a default path is probably unnecessary.
2014-07-26add support for LC_TIME and LC_MESSAGES translationsRich Felker7-13/+23
for LC_MESSAGES, translation of strerror and similar literal message functions is supported. for messages in other places (particularly the dynamic linker) that use format strings, translation is not yet supported. in order to make it possible and safe, such messages will need to be refactored to separate the textual content from the format. for LC_TIME, the day and month names and strftime-style format strings provided by nl_langinfo are supported for translation. however there may be limitations, as some of the original C-locale nl_langinfo strings are non-unique and thus perhaps non-suitable as keys. overall, the locale support activated by this commit should not be seen as complete and polished but as a basis for beginning to test locale functionality and implement locales.
2014-07-26add missing yes/no strings to nl_langinfoRich Felker1-2/+2
these were removed from the standard but still offered as an extension in langinfo.h, so nl_langinfo should support them.
2014-07-26fix nl_langinfo table for LC_TIME era-related itemsRich Felker1-1/+2
due to a skipped slot and missing null terminator, the last few strings were off by one or two slots from their item codes.
2014-07-26implement mo file string lookup for translationsRich Felker4-0/+71
the core is based on a binary search; hash table is not used. both native and reverse-endian mo files are supported. all offsets read from the mapped mo file are checked against the mapping size to prevent the possibility of reads outside the mapping. this commit has no observable effects since there are not yet any callers to the message translation code.
2014-07-24implement locale file loading and state for remaining locale categoriesRich Felker4-2/+80
there is still no code which actually uses the loaded locale files, so the main observable effect of this commit is that calls to setlocale store and give back the names of the selected locales for the remaining categories (LC_TIME, LC_COLLATE, LC_MONETARY) if a locale file by the requested name could be loaded.
2014-07-24fix locale environment variable logic for empty stringsRich Felker1-3/+3
per POSIX (XBD 8.2) LC_*/LANG environment variables set to to the empty string are supposed to be treated as if they were not set at all.
2014-07-19add issetugid function to check for elevated privilegeBrent Cook1-0/+7
this function provides a way for third-party library code to use the same logic that's used internally in libc for suppressing untrusted input/state (e.g. the environment) when the application is running with privleges elevated by the setuid or setgid bit or some other mechanism. its semantics are intended to match the openbsd function by the same name. there was some question as to whether this function is necessary: getauxval(AT_SECURE) was proposed as an alternative. however, this has several drawbacks. the most obvious is that it asks programmers to be aware of an implementation detail of ELF-based systems (the aux vector) rather than simply the semantic predicate to be checked. and trying to write a safe, reliable version of issetugid in terms of getauxval is difficult. for example, early versions of the glibc getauxval did not report ENOENT, which could lead to false negatives if AT_SECURE was not present in the aux vector (this could probably only happen when running on non-linux kernels under linux emulation, since glibc does not support linux versions old enough to lack AT_SECURE). as for musl, getauxval has always properly reported errors, but prior to commit 7bece9c2095ee81f14b1088f6b0ba2f37fecb283, the musl implementation did not emulate AT_SECURE if missing, which would result in a false positive. since musl actually does partially support kernels that lack AT_SECURE, this was problematic. the intent is that library authors will use issetugid if its availability is detected at build time, and only fall back to the unreliable alternatives on systems that lack it. patch by Brent Cook. commit message/rationale by Rich Felker.
2014-07-18fix missing flags arg to fstatat syscall in fstat fallback pathRich Felker1-1/+1
this code path is used only on archs without the plain, non-at syscalls, and only when the fstat syscall fails with EBADF on a valid file descriptor. this in turn can happen only for O_PATH file descriptors, and may not happen at all on the newer kernels needed for supporting such archs. with the flags argument omitted, spurious fstat failures may happen when the argument register happens to have the AT_SYMLINK_NOFOLLOW bit set.
2014-07-18add or1k (OpenRISC 1000) architecture portStefan Kristiansson10-0/+187
With the exception of a fenv implementation, the port is fully featured. The port has been tested in or1ksim, the golden reference functional simulator for OpenRISC 1000. It passes all libc-test tests (except the math tests that requires a fenv implementation). The port assumes an or1k implementation that has support for atomic instructions (l.lwa/l.swa). Although it passes all the libc-test tests, the port is still in an experimental state, and has yet experienced very little 'real-world' use.
2014-07-17provide getauxval(AT_SECURE) even if it is missing from the aux vectorRich Felker1-0/+1
this could happen on 2.4-series linux kernels that predate AT_SECURE and possibly on other kernels that are emulating the linux syscall API but not providing AT_SECURE in the aux vector at startup. in principle applications should be checking errno anyway, but this does not really work. to be secure, the caller would have to treat ENOENT (indeterminate result) as possibly-suid and thereby disable functionality in the typical non-suid usage case. and since glibc only runs on kernels that provide AT_SECURE, applications written to the glibc getauxval API might simply assume it succeeds.
2014-07-17remove useless infinite loop from end of exit functionRich Felker1-1/+0
this was originally added as a cheap but portable way to quell warnings about reaching the end of a function that does not return, but since _Exit is marked _Noreturn, it's not needed. removing it makes the call to _Exit into a tail call and shaves off a few bytes of code from minimal static programs.
2014-07-17fix crash in regexec for nonzero nmatch argument with REG_NOSUBRich Felker1-0/+1
per POSIX, the nmatch and pmatch arguments are ignored when the regex was compiled with REG_NOSUB.
2014-07-16work around constant folding bug 61144 in gcc 4.9.0 and 4.9.1Rich Felker7-9/+9
previously we detected this bug in configure and issued advice for a workaround, but this turned out not to work. since then gcc 4.9.0 has appeared in several distributions, and now 4.9.1 has been released without a fix despite this being a wrong code generation bug which is supposed to be a release-blocker, per gcc policy. since the scope of the bug seems to affect only data objects (rather than functions) whose definitions are overridable, and there are only a very small number of these in musl, I am just changing them from const to volatile for the time being. simply removing the const would be sufficient to make gcc 4.9.1 work (the non-const case was inadvertently fixed as part of another change in gcc), and this would also be sufficient with 4.9.0 if we forced -O0 on the affected files or on the whole build. however it's cleaner to just remove all the broken compiler detection and use volatile, which will ensure that they are never constant-folded. the quality of a non-broken compiler's output should not be affected except for the fact that these objects are no longer const and thus possibly add a few bytes to data/bss. this change can be reconsidered and possibly reverted at some point in the future when the broken gcc versions are no longer relevant.
2014-07-16simplify __stdio_exit static linking logicRich Felker4-16/+12
the purpose of this logic is to avoid linking __stdio_exit unless any stdio reads (which might require repositioning the file offset at exit time) or writes (which might require flushing at exit time) could have been performed. previously, exit called two wrapper functions for __stdio_exit named __flush_on_exit and __seek_on_exit. both of these functions actually performed both tasks (seek and flushing) by calling the underlying __stdio_exit. in order to avoid doing this twice, an overridable data object __towrite_used was used to cause __seek_on_exit to act as a nop when __towrite was linked. now, exit only makes one call, directly to __stdio_exit. this is satisfiable by a weak dummy definition in exit.c, but the real definition is pulled in by either __toread.c or __towrite.c through their referencing a symbol which is defined only in __stdio_exit.c.
2014-07-11implement the LOG_CONS option in syslogRich Felker1-1/+9
this was previously a no-op, somewhat intentionally, because I failed to understand that it only has an effect when sending to the logging facility fails and thus is not the nuisance that it would be if always sent output to the console.
2014-07-11suppress early syslog return when log socket cannot be openedRich Felker1-4/+1
this behavior is no longer valid in general, and was never necessary. if the LOG_PERROR option is set, output to stderr could still succeed. also, when the LOG_CONS option is added, it will need syslog to proceed even if opening the log socket fails.
2014-07-11implement the LOG_PERROR option in syslogRich Felker1-2/+4
this is a nonstandard feature, but easy and inexpensive to add. since the corresponding macro has always been defined in our syslog.h, it makes sense to actually support it. applications may reasonably be using the presence of the macro to assume that the feature is supported. the behavior of omitting the 'header' part of the log message does not seem to be well-documented, but matches other implementations (at least glibc) which have this option. based on a patch by Clément Vasseur, but simplified using %n.
2014-07-11fix the %m specifier in syslogClément Vasseur1-0/+3
errno must be saved upon vsyslog entry, otherwise its value could be changed by some libc function before reaching the %m handler in vsnprintf.
2014-07-11explicitly reject empty names in dynamic linker load_library functionRich Felker1-0/+5
previously passing an empty string for name resulted in failure, as expected, but only after spurious syscalls, and it produced confusing errno values (and thus dlerror strings). in addition to dlopen calls, this issue affected use of LD_PRELOAD with trailing whitespace or colon characters.
2014-07-11make dynamic linker accept colon as a separator for LD_PRELOADRich Felker1-2/+2
2014-07-08fix typo in microblaze setjmp asmRich Felker1-1/+1
r24 was wrongly being saved at a misaligned offset of 30 rather than the correct offset of 40 in the jmp_buf. the exact effects of this error have not been studied, but it's clear that the value of r24 was lost across setjmp/longjmp and the saved values of r21 and/or r22 may also have been corrupted.
2014-07-06rename file containing pthread_cleanup_push and pop for consistencyRich Felker1-0/+0
2014-07-06rework cancellation weak alias logic not to depend on archive orderRich Felker3-6/+12
if the order of object files in the static archive libc.a was not respected by the linker, the old logic could wrongly cause POSIX symbols outside of the ISO C namespace to be pulled into pure C programs. this should not happen with well-behaved linkers, but relying on the link order was a bad idea anyway. files are renamed to better reflect their contents now that they don't need names to control their order as members in the archive file.
2014-07-06fix multiple issues in legacy function getpassRich Felker1-5/+6
1. failure to output a newline after the password is read 2. fd leaks via missing FD_CLOEXEC 3. fd leaks via failure-to-close when any of the standard streams are closed at the time of the call 4. wrongful fallback to use of stdin when opening /dev/tty fails 5. wrongful use of stderr rather than /dev/tty for prompt 6. failure to report error reading password
2014-07-05eliminate use of cached pid from thread structureRich Felker8-12/+9
the main motivation for this change is to remove the assumption that the tid of the main thread is also the pid of the process. (the value returned by the set_tid_address syscall was used to fill both fields despite it semantically being the tid.) this is historically and presently true on linux and unlikely to change, but it conceivably could be false on other systems that otherwise reproduce the linux syscall api/abi. only a few parts of the code were actually still using the cached pid. in a couple places (aio and synccall) it was a minor optimization to avoid a syscall. caching could be reintroduced, but lazily as part of the public getpid function rather than at program startup, if it's deemed important for performance later. in other places (cancellation and pthread_kill) the pid was completely unnecessary; the tkill syscall can be used instead of tgkill. this is actually a rather subtle issue, since tgkill is supposedly a solution to race conditions that can affect use of tkill. however, as documented in the commit message for commit 7779dbd2663269b465951189b4f43e70839bc073, tgkill does not actually solve this race; it just limits it to happening within one process rather than between processes. we use a lock that avoids the race in pthread_kill, and the use in the cancellation signal handler is self-targeted and thus not subject to tid reuse races, so both are safe regardless of which syscall (tgkill or tkill) is used.
2014-07-02properly pass current locale to *_l functions when used internallyRich Felker8-8/+16
this change is presently non-functional since the callees do not yet use their locale argument for anything.
2014-07-02consolidate str[n]casecmp_l into str[n]casecmp source filesRich Felker4-13/+16
this is mainly done for consistency with the ctype functions and to declutter the src/locale directory.
2014-07-02consolidate *_l ctype/wctype functions into their non-_l source filesRich Felker61-213/+256
the main practical purposes of this commit are to remove a huge amount of clutter from the src/locale directory, to cut down on the length of the $(AR) and $(LD) command lines, and to reduce the amount of space wasted by object file headers in the static libc.a. build time may also be reduced, though this has not been measured. as an additional justification, if there ever were a need for the behavior of these functions to vary by locale, it would be necessary for the non-_l versions to call the _l versions, so that linking the former without the latter would not be possible anyway.
2014-07-02add locale frameworkRich Felker9-22/+186
this commit adds non-stub implementations of setlocale, duplocale, newlocale, and uselocale, along with the data structures and minimal code needed for representing the active locale on a per-thread basis and optimizing the common case where thread-local locale settings are not in use. at this point, the data structures only contain what is necessary to represent LC_CTYPE (a single flag) and LC_MESSAGES (a name for use in finding message translation files). representation for the other categories will be added later; the expectation is that a single pointer will suffice for each. for LC_CTYPE, the strings "C" and "POSIX" are treated as special; any other string is accepted and treated as "C.UTF-8". for other categories, any string is accepted after being truncated to a maximum supported length (currently 15 bytes). for LC_MESSAGES, the name is kept regardless of whether libc itself can use such a message translation locale, since applications using catgets or gettext should be able to use message locales libc is not aware of. for other categories, names which are not successfully loaded as locales (which, at present, means all names) are treated as aliases for "C". setlocale never fails. locale settings are not yet used anywhere, so this commit should have no visible effects except for the contents of the string returned by setlocale.