musl/WHATSNEW

0.5.0 - initial release



0.5.9 - signal ABI bugfix, various cleanup and fixes:

sigset_t was wrongly defined as 1024 bytes instead of 1024 bits,
breaking the intended ABI compatibility with the LSB/glibc sigaction
structure. users should upgrade immediately and rebuild any libraries
or object files that might be using the incorrect definitions.

improved security against DoS with tcb shadow passwords by checking
that the file opened was really an ordinary file.

fixed a bug in the implementation of atomic ops that could have
allowed the compiler to incorrectly reorder them (in practice, gcc
with the default settings on i386 was not reordering them).

greatly improved conformance to the C and POSIX standards regarding
what the standard header files make visible. _POSIX_C_SOURCE is now
needed to get POSIX functions in standard C headers, and _XOPEN_SOURCE
or _GNU_SOURCE are required to get XSI interfaces or GNU extensions,
respectively.

many internal improvements have been made to the syscall-related code
in preparation for porting to x86_64 and other archs.



0.6.0 - x86_64 port, various important bugs fixed

new x86_64 (amd64) architecture port, contributed by Nicholas J. Kain,
along with PORTING guide. source tree layout and build system have
been improved to accommodate further ports.

various bugs that were introduced while making the headers respect C
and POSIX namespace standards have been fixed. conformance to the
standards has been improved.

fixed an inefficiency in qsort that triggered a bug (occasionaly
internal compiler error) in some versions of gcc.

fixed a major bug in the printf %n specifier that prevented it from
working and caused memory corruption.



0.7.0 - major improvements to posix conformance and completeness

implemented posix shared memory and semaphore interfaces.

implemented all remaining required pthread and clock interfaces.

major fixes to signal semantics.

greatly improved temporary file name generation for safety against
denial of service due to intentional name collisions.

added syscall wrappers for the linux inotify interface.

malloc(0) now returns a non-null pointer.

fixed printf %n specifier (again), pthread_once (it was always
hanging), and non-default-type mutex behavior.

added ucontext/sigcontext support in headers to facilitate building
libgcc with dwarf2 unwind support, and possibly other low-level tools.

improved musl-gcc compiler wrapper.

implemented many small missing functions here and there, minor header
fixes, etc.



0.7.1 - improvements to completeness, bug fixes

implemented flockfile, wprintf, and robust mutex functions.

fixed stack corruption bug in times(), minor header bugs, and some
error return value bugs in thread interfaces.



0.7.5 - new features, major optimization, and robustness

implemented POSIX timers.

optimized and simplified many thread-related functions.

eliminated resource leak races in thread cancellation. (almost all
existing implementations, including glibc, have these leaks.)

overhauled stdio implementation to take advantage of readv/writev for
reduced syscall load, and improved stdio's handling of error status.

added syscall header and interface for applications to use and
greatly simplified internal system for making syscalls.

strangthened tmpnam/tempnam/tmpfile filename generation and made the
straight C functions not depend on POSIX symbols.

fixed pthread cancellation ABI on i386 to match the LSB/glibc ABI

better double-free handling in malloc

various minor bug fixes



0.7.6 - major bug fixes

fixed rare but serious under-allocation bug in malloc.

fixed signedness bug in strchr that prevented finding high bytes.

fixed serious parsing bugs in strtold.

fixed statvfs syscall (it was always failing with EINVAL).

fixed race condition in set*id() functions with threads (possible
deadlock). further audit still needed though.

fseek no longer sets the stream error flag on failed seeks (this was
wrong and broke some programs, notably GNU m4).

nl_langinfo is no longer a dummy function. (the functionality was
previously implemented but accidentally left unused).

various small fixes have been made to the implementations and
prototypes for nonstandard and obsolete functions



0.7.7 - more bug fixes and program-compatibility improvements

fixed floating point formatting and rounding bugs in printf.

fixed broken %N$ positional argument specifiers in printf.

fixed misaligned read/overread bug in strchr which could lead to
crashes scanning tiny strings at the end of a page when the next page
is not readable, or on archs (not yet supported) that forbid
misaligned reads.

fixed breakage of statvfs on x86_64

fixed crash in getmntent_r

fixed bug in POSIX timers created with NULL sigevent argument

improved semaphore performance, and sem_wait is now interruptable by
signals, as required by POSIX.

added many compatibility and system-level interfaces, increasing the
proportion of busybox that works with musl.



0.7.8 - more bug fixes and compatibility improvements

fixed problems with ipv6 dns and address printing code that made ipv6
support practically unusable, and some other getaddrinfo bugs.

fixed broken sendmsg/recvmsg functions on x86_64 (caused by incorrect
msghdr structure).

fixed broken sigsetjmp asm on x86_64.

worked around a problem with input buffering on terminals reblocking
after getting a blank line, due to a bug in the linux readv syscall.

various improvements to the "rsyscall" system used to implement
threaded setuid, setgid, etc.

exiting/cancelling the a timer handler thread no longer kills the
timer.

fixed incorrect trailing zeros on some %g conversions in printf.

fixed buggy byte-swapping functions and moved them to inlines in
byteswap.h.

many small improvements to header/application compatibility, support
for nonstandard macros, etc.



0.7.9 release notes

new pthread cancellation implementation:
- safe against resource-leak/side-effect-leak race conditions
- safe against interruption by signal handlers
- reduced bloat in all cancellable functions
- reduced bloat for blocking cancellation

new interfaces implemented:
- realpath (limited functionality)
- wordexp (limited functionality)
- flock (nonstandard)
- forkpty (nonstandard)
- posix_fadvise
- posix_fallocate

general bug fixes:
- syslog function failure to communicate with syslogd
- bug in siginfo_t definition if wait.h was included before signal.h
- incorrect struct definitions for most of sysv ipc
- pthread_exit/cancel on timer handler wrongly destroying the timer
- linux dup2 ebusy workaround
- obscure issues in non-threaded programs using some pthread functions
- getopt_long allowed mismatch in last char of option name
- incorrect parsing of obscure ip address forms
- initgroups not working reliably (uninitialized var)
- shadow pass treating empty expiry field as pass-expired-in-1970
- bogus longjmp if pthread_exit was called from cancellation handlers

x86_64-specific bug fixes:
- fcntl file locking
- thread stack alignment
- broken select timeouts due to incorrect timeval definition



0.7.10 release notes

new features:
- ipv6 numeric string parsing
- eventfd syscall wrappers

optimizations:
- new qsort implementation using the smoothsort algorithm
- much smaller/faster sigset_t handling functions
- lowered spin count before futex wait in synchronization functions

general bug fixes:
- incorrect floating point round-to-even behavior in printf
- major bugs in pthread barrier implementation
- off-by-one error in scanf %n results
- scanf failure to report EOF when scanning for literal text
- minor missing/incorrect prototype issues
- dependency on undefined call order in fclose

compiler issue workarounds:
- incorrect inlining of variadic functions on recent gcc versions
- pcc preprocessor bug with recursive macro expansion



0.7.11 release notes

new features:
- integrated dynamic linker
- dynamic loading (dlopen/dlsym) (for dynamic-linked programs only)
- XSI search.h API
- POSIX message queues
- POSIX spawn interfaces
- BSD pseudo-random number generator API (random/srandom/initstate/etc.)
- floating point environment (limited usefulness due to gcc bugs)

general bug fixes:
- possible crashes with wordexp due to uninitialized variable
- race condition in pthread_kill (also present and unfixed in glibc/nptl)
- pthread exit destructors called too late
- dangerous unbounded vla in glob
- brk/sbrk legacy functions mismatching legacy semantics
- wcsncpy dest buffer overflow
- strncat and wcsncat possible overflows due to double-termination



0.7.12 release notes

new features:
- support for textrels in shared objects
- rpath support in dynamic linker
- stdio_ext.h functions (for better gnu software compatibility)

bug fixes:
- some compilers miscompiling dlopen due to misuse of longjmp
- safe handling of invalid long-double bit patterns (affects printf)
- workaround for bugs in linux mprotect syscall
- thread-safety for random() functions
- various minor issues



0.8.0 release notes

new features:
- chinese and japanese legacy charset support in iconv
- zero-syscall clock_gettime support (dynamic-linked x86_64 only)
- futex-based locking for stdio (previously used spinlocks)
- LD_PRELOAD and RTLD_NEXT support in dynamic linker
- strptime (mostly working but incomplete)
- posix aio (mostly working but not entirely conformant)
- memory streams (fmemopen, open_memstream, ...)
- stub/dummy implementations for various useless legacy functions
- if_nameindex

security hardening:
- setuid, etc. should not longer be able to "partially fail" with threads
- ensure suid programs start with fd 0,1,2 open
- improved openpty/forkpty failure checks

threads/synchronization bug fixes:
- dangerous spurious wakeup in pthread_join lead to early return
- race condition enabling async cancellation (delayed/lost cancellation)
- destruction/unmapping race conditions in semaphores, mutexes, rwlocks
- recursive rwlock_rdlock deadlock when a writer is waiting
- race condition in sigqueue with fork
- timer expiration thread exit wasn't running dtors
- timer threads weren't blocking signals
- close was wrongly cancellable after succeeding on some devices
- robust mutex list was not reset on fork

general bug fixes:
- incorrect logic in fread (spurious blocking; crash on write-only files)
- many corner cases and overflow cases for strtol-family functions
- various printf integer formatting issues with flags/width/precision
- incorrect iconv return value on failure
- broken FD_* macros on 64-bit targets
- clock function returning wrong value (real time not cpu time)
- siglongjmp signal mask clobbering (off-by-one pointer error)
- dynamic linker weak symbol resolution issues
- fdopendir failure to set errno
- various minor header fixes



0.8.1 release notes

bug fixes:
- mismatching prototypes caused build failure on 64-bit
- other minor prototype errors in the headers have been fixed
- various other small omissions fixed



0.8.2 release notes

new features:
- ptrace syscall support

bug fixes:
- const error (only a warning with many compilers) in lio_listio
- minor portability fixes aimed at supporting new arch targets



0.8.3 release notes

new features:
- arm port (experimental)
- better musl-gcc wrapper script for building against musl
- added clone system call

bug fixes:
- numerous header file typos, copy/paste errors, omissions
- statfs and statvfs ABI are now LSB-conformant (and actually work)



0.8.4 release notes

new features: 
- arm dynamic linker support
- process-shared pthread barriers now work
- efficient futex-requeue-based cond var broadcast
- more optional cancellation points are now cancellable
- printf accepts null pointers with %s, prints as "(null)"
- recursive mutexes are now fully reentrant
- __cxa_atexit support
- real vfork
- dynamic linker now gold-compatible
- prlimit syscall
- support for large limits with setrlimit/getrlimit (even on 32-bit)
- glob now supports GLOB_PERIOD option (GNU extension)

bug fixes:
- many serious issues in condition variables
- rwlock failure-to-wake deadlock issues
- various small header files bugs/omissions
- wrong failure return for pthread_create
- path handling issues on execvp
- lock count corruption with robust recursive mutexes on owner death
- integer overflows in atoi, etc. reading most-negative value
- spurious mremaps on every realloc of large memory chunks
- pthread cancellation failure in single-threaded programs

security:
- avoid fd_set overflow in dns lookups



0.8.5 release notes

new features:
- stdio operations are now cancellable (only when low-level io happens)
- global ctor/dtor support in main program start code and shared libs
- dynamic linker support for PIE executables (but missing startup code)
- vfork support on x86_64
- complete set of locale_t functions (all ignore the locale argument)
- provide define float_t and double_t in math.h
- lighter/faster cancellation cleanup handler register/unregister

bug fixes:
- gcc wrapper now supports -shared, -nostdlib, -nostartfiles
- removed one wrongly-classified character from iswspace set (zwsp)
- fixed crashes in dns lookup on some errors, e.g. resolv.conf missing
- "make install" no longer tries to build shared libc if disabled
- ptrace argument handling bugs fixed
- work around visibility-hidden bugs in gcc 3.x
- fix thread-pointer-loss issue when it's initialized in signal handlers
- various minor typo/misc fixes in headers

compatibility:
- glob behaves more like traditional implementations w.r.t. GLOB_MARK
- added legacy futimes, lutimes functions
- more compatibility macros in sys/param.h (nonstandard header)
- setfs[ug]id syscall wrappers (linux specific)
- fgetpwent function (nonstandard)
- utmp.h matches traditional version more closely
- caddr_t now matches glibc type (void * instead of long)
- dummy (always-fail) dlopen and dlsym functions for static linked programs
- [efg]cvt functions (previously posix, removed from standard)
- get_current_dir_name function (nonstandard)



0.8.6 release notes

bug fixes:
- fix crash in dns lookups for all static-linked, non-threaded programs



0.8.7 release notes

new features:
- c++ support with g++'s libstdc++
- c99 math library (float, long double, complex, etc.)
- numerous wchar_t functions
- a64l, l64a functions
- getdate function

compatibility:
- c89 compatibility in math.h
- syscall.h alias for sys/syscall.h
- memory.h alias for string.h
- getcwd supports null buffer argument (auto-allocation)

bug fixes:
- major fenv (floating point environment) fixes and optimizations
- strptime mishandling of day/month names
- strtoull wrongly rejecting the highest 16 possible values as overflow
- math.h constant expression fixes for INFINITY/NAN/etc.
- scanf mishandling of "0" with "%x"



0.8.8 release notes

new feature:
- major math correctness and performance improvements
- many math functions implemented in asm for i386
- some math functions (mostly long double) in asm for x86_64
- new floating point parser/converter with correct rounding
- implement wcstod, wcstof, and wcstold
- new scanf implementation - cleaner, faster, more correct
- minimal/incomplete strfmon implementation

compatibility:
- header fixes for c++
- regex code resync with TRE; support common regex extensions
- support for compiling apps with gcc's -funsigned-char
- sysconf now returns dynamic limits for open files, processes
- give dlerror proper error status stickiness
- make alloca work even with -fno-builtin

critical security fixes:
- stack-based buffer overflow in fprintf on unbuffered files

other bug fixes:
- rare gcc register allocation (miscompilation) bug in syscall wrappers
- printf was rejecting the valid (but redundant) %lf format specifier
- fixed big data bloat (missing const) in math functions
- many math fixes related to floating point exceptions and rounding
- corrected DECIMAL_DIG definitions
- tgammal was wrongly setting global signgam
- crash in wordfree with uninitialized we_offs
- fix wordexp not null-initializing the we_offs initial slots



0.8.9 release notes

bug fixes:
- major breakage in strtol and family: failure to accept leading spaces
- incorrect name for MATH_ERREXCEPT in math.h

compatibility:
- prototypes for a few additional nonstandard functions



0.8.10 release notes

new features:
- correct over/underflow detection (ERANGE setting) for strtod
- new musl-gcc wrapper, specfile based, faster and more robust
- meaningful return strings for dlerror
- new iswalpha, iswpunct, and wcwidth; sync'd to Unicode 6.1
- towupper/towlower sync'd with Unicode 6.1
- new futex-based libc-internal locks instead of spinlocks
- experimental stack protector support (minimal; no random canary)
- experimental gdb shared library tracking support

compatibility:
- getusershell family functions
- getresuid and getresgid syscall wrappers
- byte swapping macros in endian.h
- getdtablesize was wrongly declared in unistd.h for _XOPEN_SOURCE

bug fixes:
- iconv_open wrongly rejecting most dest charsets (broken in 0.8.0)
- sysconf failure when correct value is -1 (broken in 0.8.8)
- scanf and strtod family functions overreading past NAN (4 bytes vs 3)
- scanf and strtod wrongly treating "0.00000000001", etc. as 0
- many bugs in towupper/towlower (never seriously tested before)
- int8_t definition was wrong when gcc -funsigned-char was used



0.9.0 release notes

license change: MIT

new features:
- configure script, improved build system
- full stack protector support
- PIE support on x86 and x86_64
- new O(1) space, O(nm) time implementation of fnmatch
- improved support for sse2 floating point mode on x86

compatibility:
- added linux unshare syscall
- exp10/pow10 function
- sqrtl support on arm (previously missing)
- removed minimal linux/*.h headers that could conflict with real ones
- support for _LARGEFILE64_SOURCE (mapped to standard fcns with #define)
- better c89 compatibility in headers
- stub versions of sched_* functions (previously missing)
- pthread stacks no longer executable (compat with hardened kernels)
- new ar.h and lastlog.h (legacy junk)
- various other header improvements

optimization:
- additional x86_64 math asm
- better formula for acos use in i386 asm

bug fixes:
- large (up to a few %) errors in strtod for certain values due to bug
- mbsnrtowcs and wcsnrtombs were completely broken (bad exit logic)
- wide printf %.0s could fail due to uninitialized variable
- missing dlerror strings for dlsym in some cases



0.9.1 release notes

new features:
- dynamic linker can be used as a program to explicitly load/run executables
- ldd command, usable by making a symlink to the dynamic linker named ldd

bug fixes:
- major bugs in POSIX BRE parsing inherited from TRE regex code
- character matching bug in regex on ARM: WCHAR_MAX was assumed to be signed
- various obscure fixes related to signals and pthread cancellation
- remquot subnormal remainder bug
- buggy macros in (nonstandard) sys/param.h
- major bug in pthread barriers on x86_64 (out of bounds write)
- utimes (legacy) function was making wrong syscall (utime instead of utimes)
- avoid using "old" syscalls that don't exist on arm eabi linux
- broken strrchr(str, 0)
- broken mbsinit(0)
- broken wcsncmp
- syntax error in nextafter macro in tgmath.h
- missing support for -pie in musl-gcc wrapper
- abort could wrongly fail to terminate the program in some cases

compatibility:
- increase default thread stack size to 80k
- support _BSD_SOURCE feature test macro
- support _LARGEFILE64_SOURCE feature test macro (merely exposes alt names)
- lots of legacy-compatibility improvements in headers
- various minor GNU extension functions
- sysconf reporting number of available CPUs/cores
- various LSB/glibc ABI interfaces aimed at compatibility with some binaries
- use fistpll asm mnemonic instead of fistpq for compat with clang



0.9.2 release notes

bug fixes:
- pointer overflow in printf (crash on 32bit userspace, 64bit kernel)
- printf %ls over-read bug
- strtod failure to read -0x as negative zero
- flush stdio after dtors, not before
- wrong file position for buffered input streams on exit
- popen was broken when stdin/out were already closed
- broken wcwidth tables (missing many characters)
- fwrite: wrong return value of partial/failed write
- broken utf-16 conversions
- bad buffer length check in getlogin_r
- bad perror("") behavior; did not match perror(0)
- broken sysinfo syscall/structure
- stdint.h const macro signedness bugs
- broken include guards in some headers
- bogus localeconv values
- cancellation-safety for popen and pclose
- fma corner cases wrong on i386
- fcntl F_GETOWN errno missing on failure.
- char signedness bug in dynamic linker broke dlopen on arm
- mprotect failure in dynamic linker caused crash instead of error

build system:
- configure check to work around hacked-up gcc versions
- test for old binutils that can't support musl dynamic linker

compatibility:
- make _GNU_SOURCE imply _LARGEFILE64_SOURCE
- syscall wrapper for lots of nonstandard and/or legacy linux syscalls
- versionsort stub
- timegm function (inverse of gmtime)
- various minor header tweaks
- make __freading/__fwriting semantics match traditional ones
- added gnulib-compatibility stdio interfaces
- added pthread_attr_setstack interface
- make strerror_r return partial string when buffer is too small
- duplocale should accept LC_GLOBAL_LOCALE
- align ptsname_r to upcoming posix requirements
- support invalid ld80 bit patterns as extra nans.



0.9.3 release notes

new features:
- mips (32-bit, o32 abi) port, currently static-linked only
- newly overhauled crypt implementation
- improved library pathname info for debugger from the dynamic linker
- getaddrinfo (and getservbyname) now support /etc/services lookups
- pipe2 syscall wrapper
- splice and vmsplice syscall wrappers
- syscall wrappers for extended attribute interfaces
- ioperm/iopl syscall wrappers on archs that support these operations

bug fixes:
- dlsym RTLD_NEXT library search order was wrong
- multiple dlopen pathname and library name handling errors
- potential race condition in detached thread exit
- broken internal-lock-handling code not updated for futex-based __lock
- sem_trywait spurious EAGAIN errors arising from CAS failures
- workaround kernel bug in cmsghdr size_t vs socklen_t issue (64-bit)
- getservby* crash on null protocol argument
- logic error skipping failed interfaces in if_nameindex
- various minor header/declaration related issues

arm-specific bug fixes:
- broken crti/crtn startup code when gcc crtbegin/end files are linked
- sigsetjmp tail call optimization failure broke the function
- incorrect little-endian assumptions in atomic.h functions
- use of blx instruction in asm (not supported on pre-v5 arm)

build system:
- only use expensive -ffloat-store cflag on archs/compilers that need it
- make musl-gcc wrapper support -lgcc (mainly for self-hosting)



0.9.4 release notes

new features:
- blowfish crypt
- dynamic linking on mips
- arm hard float support
- BSD fgetln function in stdio
- minor header improvements for compatibility
- support for CROSS_COMPILE variable to configure
- legacy significand function
- better support for SUSv3-targeted programs

performance:
- assembly (string ops based) memcpy for i386 and x86_64
- reduce printf overhead

bug fixes:
- failure of strtod, etc. to process extremely long strings correctly
- read overrun in wcsstr for short needles
- various major mips issues that prevented most software from working
- erroneous floating point exception behavior in i386/x86_64 exp asm
- crashes on null arguments to legacy err.h functions
- various header file/type issues
- extremely rare/obscure race condition with robust mutexes
- crypt now never returns null (most programs don't check, then crash)
- missing xattr remove functions



0.9.5 release notes

compatibility and headers:
- POSIX+XSI+BSD features enabled by default with no macros defined
- most programs can now be built without adding -D_GNU_SOURCE
- added C99 restrict keyword where required in all prototypes
- greater C89 compatibility
- cleaner, more-compatible public syscall.h
- many other header fixes
- support for compiling musl with clang/llvm

new features:
- sha 256/512 password hash functions in crypt
- GNU hash support in dynamic linker
- partial C11 coverage
- dladdr function added
- dynamic linker reports all errors instead of exiting on first error
- syscall wrappers added for most remaining linux syscalls
- provide POSIX O_SEARCH open mode using linux O_PATH

bug fixes:
- most atexit functions were being skipped when exiting
- some BSD functions were not being exposed under _BSD_SOURCE
- issues loading ssp-protected DSO into non-ssp program with dlopen

debloating:
- eliminate .eh_frame (10-15% loaded size bloat)
- optimal inline syscall asm for ARM and MIPS
- no longer force -O3 for shared libs



0.9.6 release notes

bug fixes:
- serious breakage in definition of O_ACCMODE mask (missing a bit)

new features:
- O_EXEC open mode
- md5 crypt hash function