path: root/src/internal
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2013-12-12include cleanups: remove unused headers and add feature test macrosSzabolcs Nagy-1/+0
2013-12-01add infrastructure to record and report the version of libc.soRich Felker-0/+12
this is still experimental and subject to change. for git checkouts, an attempt is made to record the exact revision to aid in bug reports and debugging. no version information is recorded in the static libc.a or binaries it's linked into.
2013-09-20fix potential deadlock bug in libc-internal locking logicRich Felker-2/+2
if a multithreaded program became non-multithreaded (i.e. all other threads exited) while one thread held an internal lock, the remaining thread would fail to release the lock. the the program then became multithreaded again at a later time, any further attempts to obtain the lock would deadlock permanently. the underlying cause is that the value of libc.threads_minus_1 at unlock time might not match the value at lock time. one solution would be returning a flag to the caller indicating whether the lock was taken and needs to be unlocked, but there is a simpler solution: using the lock itself as such a flag. note that this flag is not needed anyway for correctness; if the lock is not held, the unlock code is harmless. however, the memory synchronization properties associated with a_store are costly on some archs, so it's best to avoid executing the unlock code when it is unnecessary.
2013-09-15support configurable page size on mips, powerpc and microblazeSzabolcs Nagy-0/+6
PAGE_SIZE was hardcoded to 4096, which is historically what most systems use, but on several archs it is a kernel config parameter, user space can only know it at execution time from the aux vector. PAGE_SIZE and PAGESIZE are not defined on archs where page size is a runtime parameter, applications should use sysconf(_SC_PAGE_SIZE) to query it. Internally libc code defines PAGE_SIZE to libc.page_size, which is set to aux[AT_PAGESZ] in __init_libc and early in __dynlink as well. (Note that libc.page_size can be accessed without GOT, ie. before relocations are done) Some fpathconf settings are hardcoded to 4096, these should be actually queried from the filesystem using statfs.
2013-09-06math: remove STRICT_ASSIGN macroSzabolcs Nagy-11/+0
gcc did not always drop excess precision according to c99 at assignments before version 4.5 even if -std=c99 was requested which caused badly broken mathematical functions on i386 when FLT_EVAL_METHOD!=0 but STRICT_ASSIGN was not used consistently and it is worked around for old compilers with -ffloat-store so it is no longer needed the new convention is to get the compiler respect c99 semantics and when excess precision is not harmful use float_t or double_t or to specialize code using FLT_EVAL_METHOD
2013-09-05math: remove libc.h include from libm.hSzabolcs Nagy-2/+0
libc.h is only for weak_alias so include it directly where it is used
2013-09-05math: cosmetic cleanup (use explicit union instead of fshape and dshape)Szabolcs Nagy-66/+56
2013-09-05math: remove *_WORD64 macros from libm.hSzabolcs Nagy-16/+0
only fma used these macros and the explicit union is clearer
2013-09-05math: remove old longdbl.hSzabolcs Nagy-113/+0
2013-09-05long double cleanup, initial commitSzabolcs Nagy-26/+28
new ldshape union, ld128 support is kept, code that used the old ldshape union was rewritten (IEEEl2bits union of freebsd libm is not touched yet) ld80 __fpclassifyl no longer tries to handle invalid representation
2013-08-03fix multiple bugs in SIGEV_THREAD timersRich Felker-1/+1
1. the thread result field was reused for storing a kernel timer id, but would be overwritten if the application code exited or cancelled the thread. 2. low pointer values were used as the indicator that the timer id is a kernel timer id rather than a thread id. this is not portable, as mmap may return low pointers on some conditions. instead, use the fact that pointers must be aligned and kernel timer ids must be non-negative to map pointers into the negative integer space. 3. signals were not blocked until after the timer thread started, so a race condition could allow a signal handler to run in the timer thread when it's not supposed to exist. this is mainly problematic if the calling thread was the only thread where the signal was unblocked and the signal handler assumes it runs in that thread.
2013-08-02debloat code that depends on /proc/self/fd/%d with shared functionRich Felker-0/+13
I intend to add more Linux workarounds that depend on using these pathnames, and some of them will be in "syscall" functions that, from an anti-bloat standpoint, should not depend on the whole snprintf framework.
2013-07-22refactor headers, especially alltypes.h, and improve C++ ABI compatRich Felker-2/+2
the arch-specific bits/ has been replaced with a generic and minimal arch-specific bits/ 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
2013-07-21add support for init/fini array in main program, and greatly simplifyRich Felker-3/+0
modern (4.7.x and later) gcc uses init/fini arrays, rather than the legacy _init/_fini function pasting and crtbegin/crtend ctors/dtors system, on most or all archs. some archs had already switched a long time ago. without following this change, global ctors/dtors will cease to work under musl when building with new gcc versions. the most surprising part of this patch is that it actually reduces the size of the init code, for both static and shared libc. this is achieved by (1) unifying the handling main program and shared libraries in the dynamic linker, and (2) eliminating the glibc-inspired rube goldberg machine for passing around init and fini function pointers. to clarify, some background: the function signature for __libc_start_main was based on glibc, as part of the original goal of being able to run some glibc-linked binaries. it worked by having the crt1 code, which is linked into every application, static or dynamic, obtain and pass pointers to the init and fini functions, which __libc_start_main is then responsible for using and recording for later use, as necessary. however, in neither the static-linked nor dynamic-linked case do we actually need crt1.o's help. with dynamic linking, all the pointers are available in the _DYNAMIC block. with static linking, it's safe to simply access the _init/_fini and __init_array_start, etc. symbols directly. obviously changing the __libc_start_main function signature in an incompatible way would break both old musl-linked programs and glibc-linked programs, so let's not do that. instead, the function can just ignore the information it doesn't need. new archs need not even provide the useless args in their versions of crt1.o. existing archs should continue to provide it as long as there is an interest in having newly-linked applications be able to run on old versions of musl; at some point in the future, this support can be removed.
2013-07-17fix missing argument in variadic syscall macrosRich Felker-1/+1
for 0-argument syscalls (1 argument to the macro, the syscall number), the __SYSCALL_NARGS_X macro's ... argument was not satisfied. newer compilers seem to care about this.
2013-06-29add some comments about the mips ksigaction structure weirdnessRich Felker-0/+3
2013-06-22fix major scanf breakage with unbuffered streams, fmemopen, etc.Rich Felker-0/+1
the shgetc api, used internally in scanf and int/float scanning code to handle field width limiting and pushback, was designed assuming that pushback could be achieved via a simple decrement on the file buffer pointer. this only worked by chance for regular FILE streams, due to the linux readv bug workaround in __stdio_read which moves the last requested byte through the buffer rather than directly back to the caller. for unbuffered streams and streams not using __stdio_read but some other underlying read function, the first character read could be completely lost, and replaced by whatever junk happened to be in the unget buffer. to fix this, simply have shgetc, when it performs an underlying read operation on the stream, store the character read at the -1 offset from the read buffer pointer. this is valid even for unbuffered streams, as they have an unget buffer located just below the start of the zero-length buffer. the check to avoid storing the character when it is already there is to handle the possibility of read-only buffers. no application-exposed FILE types are allowed to use read-only buffers, but sscanf and strto* may use them internally when calling functions which use the shgetc api.
2013-04-26transition to using functions for internal signal blocking/restoringRich Felker-0/+4
there are several reasons for this change. one is getting rid of the repetition of the syscall signature all over the place. another is sharing the constant masks without costly GOT accesses in PIC. the main motivation, however, is accurately representing whether we want to block signals that might be handled by the application, or all signals.
2013-04-06add support for program_invocation[_short]_nameRich Felker-0/+4
this is a bit ugly, and the motivation for supporting it is questionable. however the main factors were: 1. it will be useful to have this for certain internal purposes anyway -- things like syslog. 2. applications can just save argv[0] in main, but it's hard to fix non-portable library code that's depending on being able to get the invocation name without the main application's help.
2013-03-31implement pthread_getattr_npRich Felker-0/+2
this function is mainly (purely?) for obtaining stack address information, but we also provide the detach state since it's easy to do anyway.
2013-03-26remove __SYSCALL_SSLEN arch macro in favor of using public _NSIGRich Felker-3/+3
the issue at hand is that many syscalls require as an argument the kernel-ABI size of sigset_t, intended to allow the kernel to switch to a larger sigset_t in the future. previously, each arch was defining this size in syscall_arch.h, which was redundant with the definition of _NSIG in bits/signal.h. as it's used in some not-quite-portable application code as well, _NSIG is much more likely to be recognized and understood immediately by someone reading the code, and it's also shorter and less cluttered. note that _NSIG is actually 65/129, not 64/128, but the division takes care of throwing away the off-by-one part.
2013-02-17consistently use the internal name __environ for environRich Felker-1/+0
patch by Jens Gustedt. previously, the intended policy was to use __environ in code that must conform to the ISO C namespace requirements, and environ elsewhere. this policy was not followed in practice anyway, making things confusing. on top of that, Jens reported that certain combinations of link-time optimization options were breaking with the inconsistent references; this seems to be a compiler or linker bug, but having it go away is a nice side effect of the changes made here.
2013-02-01replace __wake function with macro that performs direct syscallRich Felker-1/+2
this should generate faster and smaller code, especially with inline syscalls. the conditional with cnt is ugly, but thankfully cnt is always a constant anyway so it gets evaluated at compile time. it may be preferable to make separate __wake and __wakeall macros without a count argument. priv flag is not used yet; private futex support still needs to be done at some point in the future.
2012-12-11make CMPLX macros available in complex.h in non-c11 mode as wellSzabolcs Nagy-8/+0
2012-12-07fix trailing whitespace issues that crept in here and thereRich Felker-1/+1
2012-11-15Merge remote-tracking branch 'nsz/math'Rich Felker-23/+8
2012-11-14Merge remote-tracking branch 'ppc-port/ppc-squashed'Rich Felker-0/+18
2012-11-13math: turn off the STRICT_ASSIGN workaround by defaultSzabolcs Nagy-5/+3
the volatile hack in STRICT_ASSIGN is only needed if assignment is not respected and excess precision is kept. gcc -fexcess-precision=standard and -ffloat-store both respect assignment and musl use these flags by default. i kept the macro for now so the workaround may be used for bad compilers in the future.
2012-11-13PPC port cleaned up, static linking works well now.rofl0r-24/+18
2012-11-13import preliminary ppc work by rdp.Richard Pennington-0/+24
2012-11-13complex: add C11 CMPLX macros and replace cpack with themSzabolcs Nagy-18/+5
2012-11-11add support for thread scheduling (POSIX TPS option)Rich Felker-0/+5
linux's sched_* syscalls actually implement the TPS (thread scheduling) functionality, not the PS (process scheduling) functionality which the sched_* functions are supposed to have. omitting support for the PS option (and having the sched_* interfaces fail with ENOSYS rather than omitting them, since some broken software assumes they exist) seems to be the only conforming way to do this on linux.
2012-11-11fix clobber of edx in i386 vsyscall asmRich Felker-1/+2
this function does not obey the normal calling convention; like a syscall instruction, it's expected not to clobber any registers except the return value. clobbering edx could break callers that were reusing the value cached in edx after the syscall returns.
2012-11-08clean up sloppy nested inclusion from pthread_impl.hRich Felker-8/+0
this mirrors the stdio_impl.h cleanup. one header which is not strictly needed, errno.h, is left in pthread_impl.h, because since pthread functions return their error codes rather than using errno, nearly every single pthread function needs the errno constants. in a few places, rather than bringing in string.h to use memset, the memset was replaced by direct assignment. this seems to generate much better code anyway, and makes many functions which were previously non-leaf functions into leaf functions (possibly eliminating a great deal of bloat on some platforms where non-leaf functions require ugly prologue and/or epilogue).
2012-11-08clean up stdio_impl.hRich Felker-17/+2
this header evolved to facilitate the extremely lazy practice of omitting explicit includes of the necessary headers in individual stdio source files; not only was this sloppy, but it also increased build time. now, stdio_impl.h is only including the headers it needs for its own use; any further headers needed by source files are included directly where needed.
2012-11-01fix more unused variable warningsRich Felker-0/+1
some of these were coming from stdio functions locking files without unlocking them. I believe it's useful for this to throw a warning, so I added a new macro that's self-documenting that the file will never be unlocked to avoid the warning in the few places where it's wrong.
2012-10-25use explicit visibility to optimize a few hot-path function callsRich Felker-11/+13
on x86 and some other archs, functions which make function calls which might go through a PLT incur a significant overhead cost loading the GOT register prior to making the call. this load is utterly useless in musl, since all calls are bound at library-creation time using -Bsymbolic-functions, but the compiler has no way of knowing this, and attempts to set the default visibility to protected have failed due to bugs in GCC and binutils. this commit simply manually assigns hidden/protected visibility, as appropriate, to a few internal-use-only functions which have many callers, or which have callers that are hot paths like getc/putc. it shaves about 5k off the i386 with -Os. many of the improvements are in syscall wrappers, where the benefit is just size and performance improvement is unmeasurable noise amid the syscall overhead. however, stdio may be measurably faster. if in the future there are toolchains that can do the same thing globally without introducing linking bugs, it might be worth considering removing these workarounds.
2012-10-24greatly improve freopen behaviorRich Felker-0/+1
1. don't open /dev/null just as a basis to copy flags; use shared __fmodeflags function to get the right file flags for the mode. 2. handle the case (probably invalid, but whatever) case where the original stream's file descriptor was closed; previously, the logic re-closed it. 3. accept the "e" mode flag for close-on-exec; update dup3 to fallback to using dup2 so we can simply call __dup3 instead of putting fallback logic in freopen itself.
2012-10-21accept "nan(n-char-sequence)" in strtod/scanf functionsRich Felker-1/+19
this will prevent gnulib from wrapping our strtod to handle this useless feature.
2012-10-13workaround broken hidden-visibility handling in pccRich Felker-1/+1
with this change, pcc-built musl seems to work correctly. the problem is that pcc generates GOT lookups for external-linkage symbols even if they are hidden, rather than using GOT-relative addressing. the entire reason we're using hidden visibility on the __libc object is to make it accessible prior to relocations -- not to mention inexpensive to access. unfortunately, the workaround makes it even more expensive on pcc. when the pcc issue is fixed, an appropriate version test should be added so new pcc can use the much more efficient variant.
2012-10-11comment possibly-confusing i386 vsyscall asmRich Felker-1/+13
2012-10-11i386 vsyscall support (vdso-provided sysenter/syscall instruction based)Rich Felker-16/+59
this doubles the performance of the fastest syscalls on the atom I tested it on; improvement is reportedly much more dramatic on worst-case cpus. cannot be used for cancellable syscalls.
2012-10-05support for TLS in dynamic-loaded (dlopen) modulesRich Felker-3/+4
unlike other implementations, this one reserves memory for new TLS in all pre-existing threads at dlopen-time, and dlopen will fail with no resources consumed and no new libraries loaded if memory is not available. memory is not immediately distributed to running threads; that would be too complex and too costly. instead, assurances are made that threads needing the new TLS can obtain it in an async-signal-safe way from a buffer belonging to the dynamic linker/new module (via atomic fetch-and-add based allocator). I've re-appropriated the lock that was previously used for __synccall (synchronizing set*id() syscalls between threads) as a general pthread_create lock. it's a "backwards" rwlock where the "read" operation is safe atomic modification of the live thread count, which multiple threads can perform at the same time, and the "write" operation is making sure the count does not increase during an operation that depends on it remaining bounded (__synccall or dlopen). in static-linked programs that don't use __synccall, this lock is a no-op and has no cost.
2012-10-04beginnings of full TLS support in shared librariesRich Felker-1/+1
this code will not work yet because the necessary relocations are not supported, and cannot be supported without some internal changes to how relocation processing works (coming soon).
2012-10-04TLS (GNU/C11 thread-local storage) support for static-linked programsRich Felker-0/+1
the design for TLS in dynamic-linked programs is mostly complete too, but I have not yet implemented it. cost is nonzero but still low for programs which do not use TLS and/or do not use threads (a few hundred bytes of new code, plus dependency on memcpy). i believe it can be made smaller at some point by merging __init_tls and __init_security into __libc_start_main and avoiding duplicate auxv-parsing code. at the same time, I've also slightly changed the logic pthread_create uses to allocate guard pages to ensure that guard pages are not counted towards commit charge.
2012-09-29microblaze portRich Felker-0/+13
based on initial work by rdp, with heavy modifications. some features including threads are untested because qemu app-level emulation seems to be broken and I do not have a proper system image for testing.
2012-09-09add 7-arg syscall support for mipsRich Felker-4/+8
no syscalls actually use that many arguments; the issue is that some syscalls with 64-bit arguments have them ordered badly so that breaking them into aligned 32-bit half-arguments wastes slots with padding, and a 7th slot is needed for the last argument.
2012-09-09fix broken mips syscall asmRich Felker-2/+2
this code was using $10 to save the syscall number, but $10 is not necessarily preserved by the kernel across syscalls. only mattered for syscalls that got interrupted by a signal and restarted. as far as i can tell, $25 is preserved by the kernel across syscalls.
2012-09-08syscall organization overhaulRich Felker-5/+138
now public syscall.h only exposes __NR_* and SYS_* constants and the variadic syscall function. no macros or inline functions, no __syscall_ret or other internal details, no 16-/32-bit legacy syscall renaming, etc. this logic has all been moved to src/internal/syscall.h with the arch-specific parts in arch/$(ARCH)/syscall_arch.h, and the amount of arch-specific stuff has been reduced to a minimum. changes still need to be reviewed/double-checked. minimal testing on i386 and mips has already been performed.
2012-08-17fix float parsing logic for long decimal expansionsRich Felker-1/+1
this affects at least the case of very long inputs, but may also affect shorter inputs that become long due to growth while upscaling. basically, the logic for the circular buffer indices of the initial base-10^9 digit and the slot one past the final digit, and for simplicity of the loop logic, assumes an invariant that they're not equal. the upscale loop, which can increase the length of the base-10^9 representation, attempted to preserve this invariant, but was actually only ensuring that the end index did not loop around past the start index, not that the two never become equal. the main (only?) effect of this bug was that subsequent logic treats the excessively long number as having no digits, leading to junk results.