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2014-04-16release 1.1.0v1.1.0Rich Felker-1/+29
2014-04-16add working vdso clock_gettime support, including static linkingRich Felker-5/+108
the vdso symbol lookup code is based on the original 2011 patch by Nicholas J. Kain, with some streamlining, pointer arithmetic fixes, and one symbol version matching fix. on the consumer side (clock_gettime), per-arch macros for the particular symbol name and version to lookup are added in syscall_arch.h, and no vdso code is pulled in on archs which do not define these macros. at this time, vdso is enabled only on x86_64. the vdso support at the dynamic linker level is no longer useful to libc, but is left in place for the sake of debuggers (which may need the vdso in the link map to find its functions) and possibly use with dlsym.
2014-04-15fix deadlock race in pthread_onceRich Felker-2/+1
at the end of successful pthread_once, there was a race window during which another thread calling pthread_once would momentarily change the state back from 2 (finished) to 1 (in-progress). in this case, the status was immediately changed back, but with no wake call, meaning that waiters which arrived during this short window could block forever. there are two possible fixes. one would be adding the wake to the code path where it was missing. but it's better just to avoid reverting the status at all, by using compare-and-swap instead of swap.
2014-04-15fix RLIMIT_ constants for mipsSzabolcs Nagy-2/+10
The mips arch is special in that it uses different RLIMIT_ numbers than other archs, so allow bits/resource.h to override the default RLIMIT_ numbers (empty on all archs except mips). Reported by orc.
2014-04-15add _SC_PHYS_PAGES and _SC_AVPHYS_PAGES extentions to sysconfRich Felker-2/+17
2014-04-15add namespace-protected name for sysinfo functionRich Felker-7/+9
it will be needed to implement some things in sysconf, and the syscall can't easily be used directly because the x32 syscall uses the wrong structure layout. the l (uncreative, for "linux") prefix is used since the symbol name __sysinfo is already taken for AT_SYSINFO from the aux vector. the way the x32 override of this function works is also changed to be simpler and avoid the useless jump instruction.
2014-04-15in sysconf, use getrlimit function rather than raw syscall for rlimitsRich Felker-3/+3
the syscall is deprecated (replaced by prlimit64) and does not work correctly on x32. this change mildly increases size, but is likely needed anyway for newer archs that might omit deprecated syscalls.
2014-04-15avoid linear-time if/else special cases in sysconfRich Felker-20/+35
the previous handling of cases that could not fit in the 16-bit table or which required non-constant results was extremely ugly and could not scale. the new code remaps these keys into a contiguous range that's efficient for a switch statement.
2014-04-14fix fallback code for old kernels in clock_gettimeRich Felker-1/+1
2014-04-14use dmb barrier instruction for atomics on arm v7Rich Felker-2/+9
aside from potentially offering better performance, this change is needed since the old coprocessor-based approach to barriers is deprecated in arm v7, and some compilers/assemblers issue errors when using the deprecated instruction for v7 targets.
2014-04-12use hidden visibility rather than protected for syscall internalsRich Felker-1/+1
the use of visibility at all is purely an optimization to avoid the need for the caller to load the GOT register or similar to prepare for a call via the PLT. there is no reason for these symbols to be externally visible, so hidden works just as well as protected, and using protected visibility is undesirable due to toolchain bugs and the lack of testing it receives. in particular, GCC's microblaze target is known to generate symbolic relocations in the GOT for functions with protected visibility. this in turn results in a dynamic linker which crashes under any nontrivial usage that requires making a syscall before symbolic relocations are processed.
2014-04-11math: fix aliasing violation in long double wrappersSzabolcs Nagy-2/+10
modfl and sincosl were passing long double* instead of double* to the wrapped double precision functions (on archs where long double and double have the same size). This is fixed now by using temporaries (this is not optimized to a single branch so the generated code is a bit bigger). Found by Morten Welinder.
2014-04-09fix search past the end of haystack in memmemTimo Teräs-0/+1
to optimize the search, memchr is used to find the first occurrence of the first character of the needle in the haystack before switching to a search for the full needle. however, the number of characters skipped by this first step were not subtracted from the haystack length, causing memmem to search past the end of the haystack.
2014-04-07fix printf rounding with %g for some corner case midpointsRich Felker-1/+1
the subsequent rounding code assumes the end pointer (z) accurately reflects the end of significance in the decimal expansion, but for certain large integers, spurious trailing zero slots were left behind when applying the binary exponent. issue reported by Morten Welinder; the analysis of the cause was performed by nsz, who also proposed this change.
2014-04-07fix arm atomic asm register constraintRich Felker-1/+1
the "m" constraint could give a memory reference with an offset that's not compatible with ldrex/strex, so the arm-specific "Q" constraint is needed instead.
2014-04-07use inline atomics and thread pointer on arm models supporting themRich Felker-1/+36
this is perhaps not the optimal implementation; a_cas still compiles to nested loops due to the different interface contracts of the kuser helper cas function (whose contract this patch implements) and the a_cas function (whose contract mimics the x86 cmpxchg). fixing this may be possible, but it's more complicated and thus deferred until a later time. aside from improving performance and code size, this patch also provides a means of producing binaries which can run on hardened kernels where the kuser helpers have been disabled. however, at present this requires producing binaries for armv6k or later, which will not run on older cpus. a real solution to the problem of kernels that omit the kuser helpers would be runtime detection, so that universal binaries which run on all arm cpu models can also be compatible with all kernel hardening profiles. robust detection however is a much harder problem, and will be addressed at a later time.
2014-04-07add getauxval functionRich Felker-0/+28
in a sense this implementation is incomplete since it doesn't provide the HWCAP_* macros for use with AT_HWCAP, which is perhaps the most important intended usage case for getauxval. they will be added at a later time.
2014-04-07fix failure of printf %g to strip trailing zeros in some casesRich Felker-1/+1
the code to strip trailing zeros was only looking in the last slot for up to 9 zeros, assuming that the rounding code had already removed fully-zero slots from the end. however, this ignored cases where the rounding code did not run at all, which occur when the value being printed is exactly representable in the requested precision. the simplest solution is to move the code that strips trailing zero slots to run unconditionally, immediately after rounding, rather than as the last step of rounding.
2014-04-07fix carry into uninitialized slots during printf floating point roundingRich Felker-1/+1
in cases where rounding caused a carry, the slot into which the carry was taking place was unconditionally treated as valid, despite the possibility that it could be a new slot prior to the beginning of the existing non-rounded number. in theory this could lead to unbounded runaway carry, but in order for that to happen, the whole uninitialized buffer would need to have been pre-filled with 32-bit integer values greater than or equal to 999999999. patch based on proposed fix by Morten Welinder, who also discovered and reported the bug.
2014-04-07remove some cruft from libc/tls init codeRich Felker-3/+0
2014-04-04remove cruft left behind when lazy thread pointer init was removedRich Felker-8/+0
the function itself was static, but the weak alias provided an externally visible reference and thus prevented the dead code from being omitted from the output. so this change actually reduces bloat in mandatory static-linked code.
2014-04-02add __sigsetjmp ABI-compat alias for sigsetjmpRich Felker-1/+28
2014-04-02remove struct elem entirely from hsearch.csin-29/+22
There are two changes here, both of which make sense to be done in a single patch: - Remove hash from struct elem and compute it at runtime wherever necessary. - Eliminate struct elem and use ENTRY directly. As a result we cut down on the memory usage as each element in the hash table now contains only an ENTRY not an ENTRY + size_t for the hash. The downside is that the hash needs to be computed at runtime.
2014-04-02implement hcreate_r, hdestroy_r and hsearch_rsin-30/+85
the size and alignment of struct hsearch_data are matched to the glibc definition for binary compatibility. the members of the structure do not match, which should not be a problem as long as applications correctly treat the structure as opaque. unlike the glibc implementation, this version of hcreate_r does not require the caller to zero-fill the structure before use.
2014-04-02avoid malloc failure for small requests when brk can't be extendedRich Felker-1/+23
this issue mainly affects PIE binaries and execution of programs via direct invocation of the dynamic linker binary: depending on kernel behavior, in these cases the initial brk may be placed at at location where it cannot be extended, due to conflicting adjacent maps. when brk fails, mmap is used instead to expand the heap. in order to avoid expensive bookkeeping for managing fragmentation by merging these new heap regions, the minimum size for new heap regions increases exponentially in the number of regions. this limits the number of regions, and thereby the number of fixed fragmentation points, to a quantity which is logarithmic with respect to the size of virtual address space and thus negligible. the exponential growth is tuned so as to avoid expanding the heap by more than approximately 50% of its current total size.
2014-04-02fix microblaze syscall register clobbersRich Felker-7/+7
the kernel entry point for syscalls on microblaze nominally saves and restores all registers, and testing on qemu always worked since qemu behaves this way too. however, the real kernel treats r3:r4 as a potential 64-bit return value from the syscall function, and copies both over top of the saved registers before returning to userspace. thus, we need to treat r4 as always-clobbered.
2014-03-25remove lazy ssp initializationTimo Teräs-28/+5
now that thread pointer is initialized always, ssp canary initialization can be done unconditionally. this simplifies the ldso as it does not try to detect ssp usage, and the init function itself as it is always called exactly once. this also merges ssp init path for shared and static linking.
2014-03-25if dynamic linker's relro mprotect call fails, include reason in messageRich Felker-1/+1
2014-03-25cosmetic improvements in dynamic linker cleanupRich Felker-5/+5
consistent use of braces in if/else structure, line length.
2014-03-25clean up internal dynamic linker functions enumerating phdrsTimo Teräs-28/+23
record phentsize in struct dso, so the phdrs can be easily enumerated via it. simplify all functions enumerating phdrs to require only struct dso. also merge find_map_range and find_dso to kernel_mapped_dso function that does both tasks during single phdr enumeration.
2014-03-25implement PT_GNU_RELRO supportTimo Teräs-15/+37
2014-03-24fix pointer type mismatch and misplacement of constRich Felker-2/+2
2014-03-24fix confstr return valueTimo Teräs-1/+1
per the specification, the terminating null byte is counted.
2014-03-24always initialize thread pointer at program startRich Felker-98/+118
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.
2014-03-23reduce static linking overhead from TLS support by inlining mmap syscallRich Felker-1/+9
the external mmap function is heavy because it has to handle error reporting that the kernel cannot do, and has to do some locking for arcane race-condition-avoidance purposes. for allocating initial TLS, we do not need any of that; the raw syscall suffices. on i386, this change shaves off 13% of the size of .text for the empty program.
2014-03-23include header that declares __syscall_ret where it's definedRich Felker-0/+1
in general, we aim to always include the header that's declaring a function before defining it so that the compiler can check that prototypes match. additionally, the internal syscall.h declares __syscall_ret with a visibility attribute to improve code generation for shared libc (to prevent gratuitous GOT-register loads). this declaration should be visible at the point where __syscall_ret is defined, too, or the inconsistency could theoretically lead to problems at link-time.
2014-03-20release 1.0.0v1.0.0Rich Felker-1/+43
2014-03-20remove claim of XSI coverage from READMERich Felker-2/+1
in addition to the dbm functions (which we don't intent to implement anyway), fmtmsg is still missing too. rather than adding exceptions I think it's best just to avoid making the claim.
2014-03-20update README in preparation for releaseRich Felker-59/+21
reduces the amount of news-like content on progress and development direction and focuses on the present.
2014-03-20update INSTALL file with new information and better adviceRich Felker-109/+114
the text covering an ill-advised procedure for 'bootstrapping' a new musl-based system in-place is removed. new information on targets and compilers is added. formatting improved. the remaining text is adjusted to cover both usage with musl-gcc on a non-musl-based system and upgrading a musl-based system or toolchain.
2014-03-20update COPYRIGHT file with additional contributor informationRich Felker-22/+54
2014-03-19configure: check for __ILP32__ if arch is x86_64rofl0r-0/+4
otherwise a multilib compiler used with -mx32 will not be detected properly.
2014-03-18fix signal.h breakage from moving stack_t to arch-specific bitsRich Felker-48/+50
in the previous changes, I missed the fact that both the prototype of the sigaltstack function and the definition of ucontext_t depend on stack_t.
2014-03-18fix mips stack_tRich Felker-1/+1
like almost everything on mips, this is gratuitously different.
2014-03-18move signal.h definition of stack_t to arch-specific bitsRich Felker-6/+48
it's different at least on mips. mips version will be fixed in a separate commit to show the change.
2014-03-18fix mips sigsetjmp asm to match fixed jmp_buf sizeRich Felker-1/+1
this was missed in the previous commit.
2014-03-18fix typo in filename used in sh portRich Felker-0/+0
2014-03-18fix size of mips jmp_bufRich Felker-1/+1
the excess space was unused and unintentional. this change does not affect the ABI between applications and libc. while it does theoretically affect linkage between third-party translation units using jmp_buf as part of a structure, we've already changed jmp_buf at least once on all archs, and problems were never observed, likely because such usage would be very unusual. in any case it's best to get things right now rather than making changes sometime during the 1.0.x series or later.
2014-03-18remove useless and incorrect uc_regspace member from mips ucontext_tRich Felker-1/+0
this seems to have been copied erroneously from the arm version of the file. it's fairly harmless but it's a mistake and better to fix now than later.
2014-03-18use syscall_arg_t for arguments in public syscall() functionRich Felker-7/+7
on x32, this change allows programs which use syscall() with pointers or 64-bit values as arguments to work correctly, i.e. without truncation or incorrect sign extension. on all other supported archs, syscall_arg_t is defined as long, so this change is a no-op.