improve/debloat mutex unlock error checking in pthread_cond_wait

[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)