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2019-02-07fail fdopendir for O_PATH file descriptorsRich Felker1-0/+4
fdopendir is specified to fail with EBADF if the file descriptor passed is not open for reading. while O_PATH is an extension and arguably exempt from this requirement, it's used, albeit incompletely, to implement O_SEARCH, and fdopendir should fail when passed an O_SEARCH file descriptor. the new check is performed after fstat so that we don't have to consider the possibility that the fd is invalid. an alternate solution would be attempting to pre-fill the buffer using getdents, which would fail with EBADF for us, but that seems more complex and error-prone and involves either code duplication or refactoring, so the simple fix with an additional inexpensive syscall is what I've made for now.
2018-09-12split internal lock API out of libc.h, creating lock.hRich Felker3-3/+3
this further reduces the number of source files which need to include libc.h and thereby be potentially exposed to libc global state and internals. this will also facilitate further improvements like adding an inline fast-path, if we want to do so later.
2018-09-12remove spurious inclusion of libc.h for LFS64 ABI aliasesRich Felker5-9/+5
the LFS64 macro was not self-documenting and barely saved any characters. simply use weak_alias directly so that it's clear what's being done, and doesn't depend on a header to provide a strange macro.
2018-09-12reduce spurious inclusion of libc.hRich Felker1-1/+1
libc.h was intended to be a header for access to global libc state and related interfaces, but ended up included all over the place because it was the way to get the weak_alias macro. most of the inclusions removed here are places where weak_alias was needed. a few were recently introduced for hidden. some go all the way back to when libc.h defined CANCELPT_BEGIN and _END, and all (wrongly implemented) cancellation points had to include it. remaining spurious users are mostly callers of the LOCK/UNLOCK macros and files that use the LFS64 macro to define the awful *64 aliases. in a few places, new inclusion of libc.h is added because several internal headers no longer implicitly include libc.h. declarations for __lockfile and __unlockfile are moved from libc.h to stdio_impl.h so that the latter does not need libc.h. putting them in libc.h made no sense at all, since the macros in stdio_impl.h are needed to use them correctly anyway.
2018-09-12remove unused __getdents, rename and move fileRich Felker1-12/+0
the __-prefixed filename does not make sense when the only purpose of this file is implementing a public function that's not used as a backend for implementing the standard dirent functions.
2018-07-18remove spurious declaration of __getdents from readdir.cRich Felker1-2/+0
2018-07-18fix regression in alignment of dirent structs produced by readdirRich Felker2-1/+7
commit 32482f61da7650ff10741bd5aedd66bbc3ea165b reduced the number of int members before the dirent buf from 4 to 3, thereby misaligning it mod sizeof(off_t), producing invalid accesses on any arch where alignof(off_t)==sizeof(off_t). rather than re-adding wasted padding, reorder the struct to meet the requirement and add a comment and static assertion to prevent this from getting broken again.
2018-01-09revise the definition of multiple basic locks in the codeJens Gustedt1-1/+1
In all cases this is just a change from two volatile int to one.
2015-03-03make all objects used with atomic operations volatileRich Felker1-1/+1
the memory model we use internally for atomics permits plain loads of values which may be subject to concurrent modification without requiring that a special load function be used. since a compiler is free to make transformations that alter the number of loads or the way in which loads are performed, the compiler is theoretically free to break this usage. the most obvious concern is with atomic cas constructs: something of the form tmp=*p;a_cas(p,tmp,f(tmp)); could be transformed to a_cas(p,*p,f(*p)); where the latter is intended to show multiple loads of *p whose resulting values might fail to be equal; this would break the atomicity of the whole operation. but even more fundamental breakage is possible. with the changes being made now, objects that may be modified by atomics are modeled as volatile, and the atomic operations performed on them by other threads are modeled as asynchronous stores by hardware which happens to be acting on the request of another thread. such modeling of course does not itself address memory synchronization between cores/cpus, but that aspect was already handled. this all seems less than ideal, but it's the best we can do without mandating a C11 compiler and using the C11 model for atomics. in the case of pthread_once_t, the ABI type of the underlying object is not volatile-qualified. so we are assuming that accessing the object through a volatile-qualified lvalue via casts yields volatile access semantics. the language of the C standard is somewhat unclear on this matter, but this is an assumption the linux kernel also makes, and seems to be the correct interpretation of the standard.
2014-09-05add missing legacy LFS *64 symbol aliasesSzabolcs Nagy1-0/+4
versionsort64, aio*64 and lio*64 symbols were missing, they are only needed for glibc ABI compatibility, on the source level dirent.h and aio.h already redirect them.
2014-02-25fix readdir not to set ENOENT when directory is removed while readingRich Felker1-2/+7
per POSIX, ENOENT is reserved for invalid stream position; it is an optional error and would only happen if the application performs invalid seeks on the underlying file descriptor. however, linux's getdents syscall also returns ENOENT if the directory was removed between the time it was opened and the time of the read. we need to catch this case and remap it to simple end-of-file condition (null pointer return value like an error, but no change to errno). this issue reportedly affects GNU make in certain corner cases. rather than backing up and restoring errno, I've just changed the syscall to be made in a way that doesn't affect errno (via an inline syscall rather than a call to the __getdents function). the latter still exists for the purpose of providing the public getdents alias which sets errno.
2013-12-12include cleanups: remove unused headers and add feature test macrosSzabolcs Nagy5-15/+2
2013-07-22refactor headers, especially alltypes.h, and improve C++ ABI compatRich Felker1-1/+1
the arch-specific bits/alltypes.h.sh has been replaced with a generic alltypes.h.in and minimal arch-specific bits/alltypes.h.in. this commit is intended to have no functional changes except: - exposing additional symbols that POSIX allows but does not require - changing the C++ name mangling for some types - fixing the signedness of blksize_t on powerpc (POSIX requires signed) - fixing the limit macros for sig_atomic_t on x86_64 - making dev_t an unsigned type (ABI matching goal, and more logical) in addition, some types that were wrongly defined with long on 32-bit archs were changed to int, and vice versa; this change is non-functional except for the possibility of making pointer types mismatch, and only affects programs that were using them incorrectly, and only at build-time, not runtime. the following changes were made in the interest of moving non-arch-specific types out of the alltypes system and into the headers they're associated with, and also will tend to improve application compatibility: - netdb.h now includes netinet/in.h (for socklen_t and uint32_t) - netinet/in.h now includes sys/socket.h and inttypes.h - sys/resource.h now includes sys/time.h (for struct timeval) - sys/wait.h now includes signal.h (for siginfo_t) - langinfo.h now includes nl_types.h (for nl_item) for the types in stdint.h: - types which are of no interest to other headers were moved out of the alltypes system. - fast types for 8- and 64-bit are hard-coded (at least for now); only the 16- and 32-bit ones have reason to vary by arch. and the following types have been changed for C++ ABI purposes; - mbstate_t now has a struct tag, __mbstate_t - FILE's struct tag has been changed to _IO_FILE - DIR's struct tag has been changed to __dirstream - locale_t's struct tag has been changed to __locale_struct - pthread_t is defined as unsigned long in C++ mode only - fpos_t now has a struct tag, _G_fpos64_t - fsid_t's struct tag has been changed to __fsid_t - idtype_t has been made an enum type (also required by POSIX) - nl_catd has been changed from long to void * - siginfo_t's struct tag has been removed - sigset_t's has been given a struct tag, __sigset_t - stack_t has been given a struct tag, sigaltstack - suseconds_t has been changed to long on 32-bit archs - [u]intptr_t have been changed from long to int rank on 32-bit archs - dev_t has been made unsigned summary of tests that have been performed against these changes: - nsz's libc-test (diff -u before and after) - C++ ABI check symbol dump (diff -u before, after, glibc) - grepped for __NEED, made sure types needed are still in alltypes - built gcc 3.4.6
2012-09-06use restrict everywhere it's required by c99 and/or posix 2008Rich Felker1-1/+1
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
2012-06-13add (currently stubbed due to stubbed strverscmp) versionsort functionRich Felker1-0/+8
based on patch by Emil Renner Berthing, with minor changes to dirent.h for LFS64 and organization of declarations this code should work unmodified once a real strverscmp is added, but I've been hesitant to add it because the GNU strverscmp behavior is harmful in a lot of cases (for instance if you have numeric filenames in hex). at some point I plan on trying to design a variant of the algorithm that behaves better on a mix of filename styles.
2012-04-24ditch the priority inheritance locks; use malloc's version of lockRich Felker5-12/+9
i did some testing trying to switch malloc to use the new internal lock with priority inheritance, and my malloc contention test got 20-100 times slower. if priority inheritance futexes are this slow, it's simply too high a price to pay for avoiding priority inversion. maybe we can consider them somewhere down the road once the kernel folks get their act together on this (and perferably don't link it to glibc's inefficient lock API)... as such, i've switch __lock to use malloc's implementation of lightweight locks, and updated all the users of the code to use an array with a waiter count for their locks. this should give optimal performance in the vast majority of cases, and it's simple. malloc is still using its own internal copy of the lock code because it seems to yield measurably better performance with -O3 when it's inlined (20% or more difference in the contention stress test).
2011-07-21fix errno value when fdopendir is given an invalid file descriptorRich Felker1-1/+4
this resolves an issue reported by Vasiliy Kulikov
2011-06-25optimize opendir using O_CLOEXECRich Felker1-2/+1
2011-06-06fix handling of d_name in struct direntRich Felker1-4/+3
basically there are 3 choices for how to implement this variable-size string member: 1. C99 flexible array member: breaks using dirent.h with pre-C99 compiler. 2. old way: length-1 string: generates array bounds warnings in caller. 3. new way: length-NAME_MAX string. no problems, simplifies all code. of course the usable part in the pointer returned by readdir might be shorter than NAME_MAX+1 bytes, but that is allowed by the standard and doesn't hurt anything.
2011-04-18avoid fd leak if opendir is cancelled when calloc has failedRich Felker1-1/+2
2011-04-11fix errno handling in scandir:Rich Felker1-2/+1
1. saved errno was not being restored, illegally clearing errno to 0. 2. no need to backup and save errno around free; it will not touch except perhaps when the program has already invoked UB...
2011-03-20global cleanup to use the new syscall interfaceRich Felker1-1/+1
2011-02-15finish moving 32-bit-specific junk out of source files.Rich Felker1-1/+1
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker13-0/+244