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2018-09-12overhaul internally-public declarations using wrapper headersRich Felker-2/+0
commits leading up to this one have moved the vast majority of libc-internal interface declarations to appropriate internal headers, allowing them to be type-checked and setting the stage to limit their visibility. the ones that have not yet been moved are mostly namespace-protected aliases for standard/public interfaces, which exist to facilitate implementing plain C functions in terms of POSIX functionality, or C or POSIX functionality in terms of extensions that are not standardized. some don't quite fit this description, but are "internally public" interfacs between subsystems of libc. rather than create a number of newly-named headers to declare these functions, and having to add explicit include directives for them to every source file where they're needed, I have introduced a method of wrapping the corresponding public headers. parallel to the public headers in $(srcdir)/include, we now have wrappers in $(srcdir)/src/include that come earlier in the include path order. they include the public header they're wrapping, then add declarations for namespace-protected versions of the same interfaces and any "internally public" interfaces for the subsystem they correspond to. along these lines, the wrapper for features.h is now responsible for the definition of the hidden, weak, and weak_alias macros. this means source files will no longer need to include any special headers to access these features. over time, it is my expectation that the scope of what is "internally public" will expand, reducing the number of source files which need to include *_impl.h and related headers down to those which are actually implementing the corresponding subsystems, not just using them.
2018-09-05define and use internal macros for hidden visibility, weak refsRich Felker-3/+4
this cleans up what had become widespread direct inline use of "GNU C" style attributes directly in the source, and lowers the barrier to increased use of hidden visibility, which will be useful to recovering some of the efficiency lost when the protected visibility hack was dropped in commit dc2f368e565c37728b0d620380b849c3a1ddd78f, especially on archs where the PLT ABI is costly.
2018-09-01consistently use _NSIG/8 idiom for kernel sigset size in sigactionRich Felker-3/+3
this code in sigaction was the only place where sizeof was being applied to the kernel sigaction's mask member to get the size argument to pass to the kernel. everywhere else, _NSIG/8 is used for this purpose.
2018-09-01always terminate by SIGABRT when abort is calledRich Felker-4/+21
Linux makes this surprisingly difficult, but it can be done. the trick here is using the fact that we control the implementation of sigaction to prevent changing the disposition of SIGABRT to anything but SIG_DFL after abort has tried and failed to terminate the process simply by calling raise(SIGABRT).
2018-09-01optimize raise not to make a syscall for getting tidRich Felker-3/+1
assuming signals are blocked, which they are here, the tid in the thread structure is always valid and cannot change out from under us.
2018-08-30prevent psignal/psiginfo from clobbering stderr orientation, errnoRich Felker-8/+21
these functions are specified to write to stderr but not set its orientation, presumably so that they can be used in programs operating stderr in wide mode. also, they are not allowed to clobber errno on success. save and restore to meet the requirement. psiginfo is reduced to a think wrapper around psignal, since it already behaved the same. if we want to add more detailed siginfo printing at some point this will need refactoring.
2018-06-19add m68k portRich Felker-0/+29
three ABIs are supported: the default with 68881 80-bit fpu format and results returned in floating point registers, softfloat-only with the same format, and coldfire fpu with IEEE single/double only. only the first is tested at all, and only under qemu which has fpu emulation bugs. basic functionality smoke tests have been performed for the most common arch-specific breakage via libc-test and qemu user-level emulation. some sysvipc failures remain, but are shared with other big endian archs and will be fixed separately.
2018-05-01optimize sigisemptysetRich Felker-2/+3
the static const zero set ended up getting put in bss instead of rodata, wasting writable memory, and the call to memcmp was size-inefficient. generally for nonstandard extension functions we try to avoid poking at any internals directly, but the way the zero set was setup was arguably already doing so.
2018-02-25add public interface headers to implementation filesRich Felker-0/+2
general policy is that all source files defining a public API or an ABI mechanism referenced by a public header should include the public header that declares the interface, so that the compiler or analysis tools can check the consistency of the declarations. Alexander Monakov pointed out a number of violations of this principle a few years back. fix them now.
2017-08-11ppc64: fix setjmp/longjmp handling of TOC pointerBobby Bingham-7/+14
The TOC pointer is constant within a single dso, but needs to be saved and restored around cross-dso calls. The PLT stub saves it to the caller's stack frame, and the linker adds code to the caller to restore it. With a local call, as within a single dso or with static linking, this doesn't happen and the TOC pointer is always in r2. Therefore, setjmp/longjmp need to save/restore the TOC pointer from/to different locations depending on whether the call to setjmp was a local or non-local call. It is always safe for longjmp to restore to both r2 and the caller's stack. If the call to setjmp was local, and only r2 matters and the stack location will be ignored, but is required by the ABI to be reserved for the TOC pointer. If the call was non-local, then only the stack location matters, and whatever is restored into r2 will be clobbered anyway when the caller reloads r2 from the stack. A little extra care is required for sigsetjmp, because it uses setjmp internally. After the second return from this setjmp call, r2 will contain the caller's TOC pointer instead of libc's TOC pointer. We need to save and restore the correct libc pointer before we can tail call to __sigsetjmp_tail.
2016-12-16fix crashing sigsetjmp on s390xBobby Bingham-1/+1
the bz instruction that was wrongly used only admits a small immediate displacement and cannot be used with external symbols; apparently the linker fails to diagnose the overflow.
2016-11-12work around gdb issues recognizing sigreturn trampoline on x86_64Rich Felker-8/+6
gdb can only backtrace/unwind across signal handlers if it recognizes the sa_restorer trampoline. for x86_64, gdb first attempts to determine the symbol name for the function in which the program counter resides and match it against "__restore_rt". if no name can be found (e.g. in the case of a stripped binary), the exact instruction sequence is matched instead. when matching the function name, however, gdb's unwind code wrongly considers the interval [sym,sym+size] rather than [sym,sym+size). thus, if __restore_rt begins immediately after another function, gdb wrongly identifies pc as lying within the previous adjacent function. this patch adds a nop before __restore_rt to preclude that possibility. it also removes the symbol name __restore and replaces it with a macro since the stability of whether gdb identifies the function as __restore_rt or __restore is not clear. for the no-symbols case, the instruction sequence is changed to use %rax rather than %eax to match what gdb expects. based on patch by Szabolcs Nagy, with extended description and corresponding x32 changes added.
2016-11-11add s390x portBobby Bingham-0/+32
2016-05-08add powerpc64 portBobby Bingham-0/+41
2016-04-18add mips n32 port (ILP32 ABI for mips64)Rich Felker-0/+47
based on patch submitted by Jaydeep Patil, with minor changes.
2016-03-06add mips64 portRich Felker-0/+47
patch by Mahesh Bodapati and Jaydeep Patil of Imagination Technologies.
2015-12-15fix crash when signal number 0 is passed to sigactionRich Felker-5/+1
this error case was overlooked in the old range checking logic. new check is moved out of __libc_sigaction to the public wrapper in order to unify the error path and reduce code size.
2015-11-11eliminate use of SHARED macro to suppress visibility attributesRich Felker-2/+0
this is the first and simplest stage of removal of the SHARED macro, which will eventually allow libc.a and to be produced from the same object files. the original motivation for these #ifdefs which are now being removed was to allow building a static-only libc using a compiler that does not support visibility. however, SHARED was the wrong condition to test for this anyway; various assembly-language sources refer to hidden symbols and declare them with the .hidden directive, making it wrong to define the referenced symbols as non-hidden. if there is a need in the future to build libc using compilers that lack visibility, support could be moved to the build system or perhaps the __PIC__ macro could be checked instead of SHARED.
2015-11-10explicitly assemble all arm asm sources as UALRich Felker-0/+3
these files are all accepted as legacy arm syntax when producing arm code, but legacy syntax cannot be used for producing thumb2 with access to the full ISA. even after switching to UAL, some asm source files contain instructions which are not valid in thumb mode, so these will need to be addressed separately.
2015-09-23fix signal return for sh/fdpicRich Felker-4/+0
the restorer function pointer provided in the kernel sigaction structure is interpreted by the kernel as a raw code address, not a function descriptor. this commit moves the declarations of the __restore and __restore_rt symbols to ksigaction.h so that arch versions of the file can override them, and introduces a version for sh which declares them as objects rather than functions. an alternate solution would have been defining SA_RESTORER to 0 so that the functions are not used, but this both requires executable stack (since the sh kernel does not have a vdso page with permanent restorer functions) and crashes on qemu user-level emulation.
2015-09-09remove unused (and invalid) C version of sigsetjmpRich Felker-17/+0
originally, the comment in this code was correct and it would likely work if the compiler generated a tail call to setjmp. however, commit 583e55122e767b1586286a0d9c35e2a4027998ab redesigned sigsetjmp and siglongjmp such that the old C implementation (which was not intended to be used) is not even conceptually correct. remove it in the interest of avoiding confusion when porting to new archs.
2015-06-16switch to using trap number 31 for syscalls on shRich Felker-2/+2
nominally the low bits of the trap number on sh are the number of syscall arguments, but they have never been used by the kernel, and some code making syscalls does not even know the number of arguments and needs to pass an arbitrary high number anyway. sh3/sh4 traditionally used the trap range 16-31 for syscalls, but part of this range overlapped with hardware exceptions/interrupts on sh2 hardware, so an incompatible range 32-47 was chosen for sh2. using trap number 31 everywhere, since it's in the existing sh3/sh4 range and does not conflict with sh2 hardware, is a proposed unification of the kernel syscall convention that will allow binaries to be shared between sh2 and sh3/sh4. if this is not accepted into the kernel, we can refit the sh2 target with runtime selection mechanisms for the trap number, but doing so would be invasive and would entail non-trivial overhead.
2015-05-02fix crash in x32 sigsetjmpRich Felker-0/+1
the 64-bit push reads not only the 32-bit return address but also the first 32 signal mask bits. if any were nonzero, the return address obtained will be invalid. at some point storage of the return address should probably be moved to follow the saved mask so that there's plenty room and the same code can be used on x32 and regular x86_64, but for now I want a fix that does not risk breaking x86_64, and this simple re-zeroing works.
2015-04-27fix sh jmp_buf size to match ABIRich Felker-2/+2
while the sh port is still experimental and subject to ABI instability, this is not actually an application/libc boundary ABI change. it only affects third-party APIs where jmp_buf is used in a shared structure at the ABI boundary, because nothing anywhere near the end of the jmp_buf object (which includes the oversized sigset_t) is accessed by libc. both glibc and uclibc have 15-slot jmp_buf for sh. presumably the smaller version was used in musl because the slots for fpu status register and thread pointer register (gbr) were incorrect and must not be restored by longjmp, but the size should have been preserved, as it's generally treated as a libc-agnostic ABI property for the arch, and having extra slots free in case we ever need them for something is useful anyway.
2015-04-24fix build regression in aarch64 sigsetjmpRich Felker-2/+2
at least some assembler versions do not accept the register name lr. use the name x30 instead.
2015-04-19remove invalid PLT calls from or1k asmRich Felker-3/+4
analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
2015-04-19remove possible-textrels from powerpc asmRich Felker-2/+3
these are perfectly fine with ld-time symbol binding, but otherwise result in textrels. they cannot be replaced with @PLT jump targets because the PLT thunks require a GOT register to be setup, so use a hidden alias instead.
2015-04-19remove invalid PLT calls from microblaze asmRich Felker-2/+3
analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
2015-04-19remove invalid PLT calls from sh asmRich Felker-2/+3
these are perfectly fine with ld-time symbol binding, but if the calls go through a PLT thunk, they are invalid because the caller does not setup a GOT register. use a hidden alias to bypass the issue.
2015-04-18remove potentially PIC-incompatible relocations from x86_64 and x32 asmRich Felker-4/+4
analogous to commit 8ed66ecbcba1dd0f899f22b534aac92a282f42d5 for i386.
2015-04-18remove the last of possible-textrels from i386 asmRich Felker-2/+3
none of these are actual textrels because of ld-time binding performed by -Bsymbolic-functions, but I'm changing them with the goal of making ld-time binding purely an optimization rather than relying on it for semantic purposes. in the case of memmove's call to memcpy, making it explicit that the memmove asm is assuming the forward-copying behavior of the memcpy asm is desirable anyway; in case memcpy is ever changed, the semantic mismatch would be apparent while editing memmcpy.s.
2015-04-17redesign sigsetjmp so that signal mask is restored after longjmpRich Felker-133/+177
the conventional way to implement sigsetjmp is to save the signal mask then tail-call to setjmp; siglongjmp then restores the signal mask and calls longjmp. the problem with this approach is that a signal already pending, or arriving between unmasking of signals and restoration of the saved stack pointer, will have its signal handler run on the stack that was active before siglongjmp was called. this can lead to unbounded stack usage when siglongjmp is used to leave a signal handler. in the new design, sigsetjmp saves its own return address inside the extended part of the sigjmp_buf (outside the __jmp_buf part used by setjmp) then calls setjmp to save a jmp_buf inside its own execution. it then tail-calls to __sigsetjmp_tail, which uses the return value of setjmp to determine whether to save the current signal mask or restore a previously-saved mask. as an added bonus, this design makes it so that siglongjmp and longjmp are identical. this is useful because the __longjmp_chk function we need to add for ABI-compatibility assumes siglongjmp and longjmp are the same, but for different reasons -- it was designed assuming either can access a flag just past the __jmp_buf indicating whether the signal masked was saved, and act on that flag. however, early versions of musl did not have space past the __jmp_buf for the non-sigjmp_buf version of jmp_buf, so our setjmp cannot store such a flag without risking clobbering memory on (very) old binaries.
2015-03-11add aarch64 portSzabolcs Nagy-0/+27
This adds complete aarch64 target support including bigendian subarch. Some of the long double math functions are known to be broken otherwise interfaces should be fully functional, but at this point consider this port experimental. Initial work on this port was done by Sireesh Tripurari and Kevin Bortis.
2014-12-18use tkill instead of tgkill in implementing raiseRich Felker-3/+2
this shaves off a useless syscall for getting the caller's pid and brings raise into alignment with other functions which were adapted to use tkill rather than tgkill. commit 83dc6eb087633abcf5608ad651d3b525ca2ec35e documents the rationale for this change, and in particular why the tgkill syscall is useless for its designed purpose of avoiding races.
2014-07-18add or1k (OpenRISC 1000) architecture portStefan Kristiansson-0/+22
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.
2014-06-22add __sysv_signal abi-compat alias for the signal functionRich Felker-0/+1
it should be noted that the "real" __sysv_signal, which we do not implement, is semantically different from signal. references to __sysv_signal arise in code built against glibc under certain combinations of feature test macros, and are almost surely unintentional since the legacy sysv signal behavior has fundamental race conditions that cannot be worked around and which make it impossible to use safely.
2014-04-02add __sigsetjmp ABI-compat alias for sigsetjmpRich Felker-1/+28
2014-03-24always initialize thread pointer at program startRich Felker-4/+15
this is the first step in an overhaul aimed at greatly simplifying and optimizing everything dealing with thread-local state. previously, the thread pointer was initialized lazily on first access, or at program startup if stack protector was in use, or at certain random places where inconsistent state could be reached if it were not initialized early. while believed to be fully correct, the logic was fragile and non-obvious. in the first phase of the thread pointer overhaul, support is retained (and in some cases improved) for systems/situation where loading the thread pointer fails, e.g. old kernels. some notes on specific changes: - the confusing use of libc.main_thread as an indicator that the thread pointer is initialized is eliminated in favor of an explicit has_thread_pointer predicate. - sigaction no longer needs to ensure that the thread pointer is initialized before installing a signal handler (this was needed to prevent a situation where the signal handler caused the thread pointer to be initialized and the subsequent sigreturn cleared it again) but it still needs to ensure that implementation-internal thread-related signals are not blocked. - pthread tsd initialization for the main thread is deferred in a new manner to minimize bloat in the static-linked __init_tp code. - pthread_setcancelstate no longer needs special handling for the situation before the thread pointer is initialized. it simply fails on systems that cannot support a thread pointer, which are non-conforming anyway. - pthread_cleanup_push/pop now check for missing thread pointer and nop themselves out in this case, so stdio no longer needs to avoid the cancellable path when the thread pointer is not available. a number of cases remain where certain interfaces may crash if the system does not support a thread pointer. at this point, these should be limited to pthread interfaces, and the number of such cases should be fewer than before.
2014-03-18fix mips sigsetjmp asm to match fixed jmp_buf sizeRich Felker-1/+1
this was missed in the previous commit.
2014-02-27rename superh port to "sh" for consistencyRich Felker-0/+0
linux, gcc, etc. all use "sh" as the name for the superh arch. there was already some inconsistency internally in musl: the dynamic linker was searching for "ld-musl-sh.path" as its path file despite its own name being "". there was some sentiment in both directions as to how to resolve the inconsistency, but overall "sh" was favored.
2014-02-23superh portBobby Bingham-0/+51
2014-02-23x32 port (diff against vanilla x86_64)rofl0r-1/+1
2014-02-23import vanilla x86_64 code as x32rofl0r-0/+22
2014-01-07fix const-correctness in sigandset/sigorset argumentsRich Felker-2/+2
this change is consistent with the corresponding glibc functions and is semantically const-correct. the incorrect argument types without const seem to have been taken from erroneous man pages.
2013-12-13use 0 instead of NULL for null pointer constantsRich Felker-15/+8
and thereby remove otherwise-unnecessary inclusion of stddef.h
2013-12-12include cleanups: remove unused headers and add feature test macrosSzabolcs Nagy-14/+5
2013-09-16fix sigemptyset and sigfillset for mipsRich Felker-1/+10
they were leaving junk in the upper bits.
2013-08-31fix breakage in synccall due to incorrect signal restoration in sigqueueRich Felker-2/+3
commit 07827d1a82fb33262f686eda959857f0d28cd8fa seems to have introduced this issue. sigqueue is called from the synccall core, at which time, even implementation-internal signals are blocked. however, pthread_sigmask removes the implementation-internal signals from the old mask before returning, so that a process which began life with them blocked will not be able to save a signal mask that has them blocked, possibly causing them to become re-blocked later. however, this was causing sigqueue to unblock the implementation-internal signals during synccall, leading to deadlock.
2013-08-10fix _NSIG and SIGRTMAX on mipsRich Felker-1/+3
a mips signal mask contains 128 bits, enough for signals 1 through 128. however, the exit status obtained from the wait-family functions only has room for values up to 127. reportedly signal 128 was causing kernelspace bugs, so it was removed from the kernel recently; even without that issue, however, it was impossible to support it correctly in userspace. at the same time, the bug was masked on musl by SIGRTMAX incorrectly yielding 64 on mips, rather than the "correct" value of 128. now that the _NSIG issue is fixed, SIGRTMAX can be fixed at the same time, exposing the full range of signals for application use. note that the (nonstandardized) libc _NSIG value is actually one greater than the max signal number, and also one greater than the kernel headers' idea of _NSIG. this is the reason for the discrepency with the recent kernel changes. since reducing _NSIG by one brought it down from 129 to 128, rather than from 128 to 127, _NSIG/8, used widely in the musl sources, is unchanged.
2013-08-09change sigset_t functions to restrict to _NSIGRich Felker-5/+5
the idea here is to avoid advertising signals that don't exist and to make these functions safe to call (e.g. from within other parts of the implementation) on fake sigset_t objects which do not have the HURD padding.