Rich Felker [Sun, 5 Nov 2017 22:26:48 +0000 (17:26 -0500)]
adjust posix_spawn dup2 action behavior to match future requirements
the resolution to Austin Group issue #411 defined new semantics for
the posix_spawn dup2 file action in the (previously useless) case
where src and dest fd are equal. future issues will require the dup2
file action to remove the close-on-exec flag. without this change,
passing fds to a child with posix_spawn while avoiding fd-leak races
in a multithreaded parent required a complex dance with temporary fds.
based on patch by Petr Skocik. changes were made to preserve the
80-column formatting of the function and to remove code that became
unreachable as a result of the new functionality.
patch by Adrian Bunk. it fixes the regression in all cases, but
spuriously prevents use of the clz instruction on very old compiler
versions that don't define __ARM_ARCH. this may be fixed in a more
general way at some point in the future. it also omits thumb1 logic
since building as thumb1 code is currently not supported.
Rich Felker [Sat, 21 Oct 2017 16:17:49 +0000 (12:17 -0400)]
fix regression in glob with literal . or .. path component
commit 8c4be3e2209d2a1d3874b8bc2b474668fcbbbac6 was written to
preclude the GLOB_PERIOD extension from matching these directory
entries, but also precluded literal matches.
adjust the check that excludes . and .. to check whether the
GLOB_PERIOD flag is in effect, so that it cannot alter behavior in
cases governed by the standard, and also don't exclude . or .. in any
case where normal glob behavior (fnmatch's FNM_PERIOD flag) would have
included one or both of them (patterns such as ".*").
it's still not clear whether this is the preferred behavior for
GLOB_PERIOD, but at least it's clear that it can no longer break
applications which are not relying on quirks of a nonstandard feature.
Will Dietz [Thu, 14 Sep 2017 21:32:59 +0000 (16:32 -0500)]
posix_spawn: use larger stack to cover worst-case in execvpe
execvpe stack-allocates a buffer used to hold the full path
(combination of a PATH entry and the program name)
while searching through $PATH, so at least
NAME_MAX+PATH_MAX is needed.
The stack size can be made conditionally smaller
(the current 1024 appears appropriate)
should this larger size be burdensome in those situations.
Rich Felker [Wed, 18 Oct 2017 18:50:03 +0000 (14:50 -0400)]
in dns parsing callback, enforce MAXADDRS to preclude overflow
MAXADDRS was chosen not to need enforcement, but the logic used to
compute it assumes the answers received match the RR types of the
queries. specifically, it assumes that only one replu contains A
record answers. if the replies to both the A and the AAAA query have
their answer sections filled with A records, MAXADDRS can be exceeded
and clobber the stack of the calling function.
Rich Felker [Sat, 14 Oct 2017 03:08:21 +0000 (23:08 -0400)]
fix incorrect base name offset from nftw when pathname ends in slash(es)
the rightmost '/' character is not necessarily the delimiter before
the basename; it could be a spurious trailing character on the
directory name.
this change does not introduce any normalization of pathnames or
stripping of trailing slashes, contrary to at least glibc and perhaps
other implementations; it jusst prevents their presence from breaking
things. whether further changes should be made is an open question
that may depend on conformance and/or application compatibility
considerations.
Rich Felker [Sat, 14 Oct 2017 03:00:34 +0000 (23:00 -0400)]
fix read-after-free type error in pthread_detach
calling __unlock on t->exitlock is not valid because __unlock reads
the waiters count after making the atomic store that could allow
pthread_exit to continue and unmap the thread's stack and the object t
points to. for now, inline the __unlock logic with an unconditional
futex wake operation so that the waiters count is not needed.
once __lock/__unlock have been made safe for self-synchronized
destruction, we could switch back to using them.
Szabolcs Nagy [Sun, 17 Sep 2017 17:31:20 +0000 (17:31 +0000)]
math: rewrite fma with mostly int arithmetics
the freebsd fma code failed to raise underflow exception in some
cases in nearest rounding mode (affects fmal too) e.g.
fma(-0x1p-1000, 0x1.000001p-74, 0x1p-1022)
and the inexact exception may be raised spuriously since the fenv
is not saved/restored around the exact multiplication algorithm
(affects x86 fma too).
another issue is that the underflow behaviour when the rounded result
is the minimal normal number is target dependent, ieee754 allows two
ways to raise underflow for inexact results: raise if the result before
rounding is in the subnormal range (e.g. aarch64, arm, powerpc) or if
the result after rounding with infinite exponent range is in the
subnormal range (e.g. x86, mips, sh).
to avoid all these issues the algorithm was rewritten with mostly int
arithmetics and float arithmetics is only used to get correct rounding
and raise exceptions according to the behaviour of the target without
any fenv.h dependency. it also unifies x86 and non-x86 fma.
fmaf is not affected, fmal need to be fixed too.
this algorithm depends on a_clz_64 and it required a few spurious
instructions to make sure underflow exception is raised in a particular
corner case. (normally FORCE_EVAL(tiny*tiny) would be used for this,
but on i386 gcc is broken if the expression is constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57245
and there is no easy portable fix for the macro.)
Rich Felker [Fri, 13 Oct 2017 14:39:51 +0000 (10:39 -0400)]
for executing init array functions, use function type with prototype
this is for consistency with the way it's done in in the dynamic
linker, avoiding a deprecated C feature (non-prototype function
types), and improving code generation. GCC unnecessarily uses the
variadic calling convention (e.g. clearing rax on x86_64) when making
a call where the argument types are not known for compatibility with
wrong code which calls variadic functions this way. (C on the other
hand is clear that such calls have undefined behavior.)
Rich Felker [Fri, 13 Oct 2017 14:23:48 +0000 (10:23 -0400)]
fix access by setjmp and longjmp to __hwcap on arm built as thumb2
this is a subtle issue with how the assembler/linker work. for the adr
pseudo-instruction used to find __hwcap, the assembler in thumb mode
generates a 16-bit thumb add instruction which can only represent
word-aligned addresses, despite not knowing the alignment of the
label. if the setjmp function is assigned a non-multiple-of-4 address
at link time, the load then loads from the wrong address (the last
instruction rather than the data containing the offset) and ends up
reading nonsense instead of the value of __hwcap. this in turn causes
the checks for floating-point/vector register sets (e.g. IWMMX) to
evaluate incorrectly, crashing when setjmp/longjmp try to save/restore
those registers.
under some conditions, the mmap syscall wrongly fails with EPERM
instead of ENOMEM when memory is exhausted; this is probably the
result of the kernel trying to fit the allocation somewhere that
crosses into the kernel range or below mmap_min_addr. in any case it's
a conformance bug, so work around it. for now, only handle the case of
anonymous mappings with no requested address; in other cases EPERM may
be a legitimate error.
this indirectly fixes the possibility of malloc failing with the wrong
errno value.
GLOB_PERIOD is a gnu extension, and GNU glob does not seem to honor it
except in the last path component. it's not clear whether this a bug
or intentional, but it seems reasonable that it should exclude the
special entries . and .. when walking.
changes based on report and analysis by Julien Ramseier.
don't treat numeric port strings as servent records in getservby*()
some applications use getservbyport to find port numbers that are not
assigned to a service; if getservbyport always succeeds with a numeric
string as the result, they fail to find any available ports.
POSIX doesn't seem to mandate the behavior one way or another. it
specifies an abstract service database, which an implementation could
define to include numeric port strings, but it makes more sense to
align behavior with traditional implementations.
based on patch by A. Wilcox. the original patch only changed
getservbyport[_r]. to maintain a consistent view of the "service
database", I have also modified getservbyname[_r] to exclude numeric
port strings.
fix signal masking race in pthread_create with priority attributes
if the parent thread was able to set the new thread's priority before
it reached the check for 'startlock', the new thread failed to restore
its signal mask and thus ran with all signals blocked.
concept for patch by Sergei, who reported the issue; unnecessary
changes were removed and comments added since the whole 'startlock'
thing is non-idiomatic and confusing. eventually it should be replaced
with use of idiomatic synchronization primitives.
Szabolcs Nagy [Sat, 18 Feb 2017 00:50:09 +0000 (00:50 +0000)]
make syscall.h consistent with linux
most of the found naming differences don't matter to musl, because
internally it unifies the syscall names that vary across targets,
but for external code the names should match the kernel uapi.
aarch64:
__NR_fstatat is called __NR_newfstatat in linux.
__NR_or1k_atomic got mistakenly copied from or1k.
arm:
__NR_arm_sync_file_range is an alias for __NR_sync_file_range2
__NR_fadvise64_64 is called __NR_arm_fadvise64_64 in linux,
the old non-arm name is kept too, it should not cause issues.
(powerpc has similar nonstandard fadvise and it uses the
normal name.)
i386:
__NR_madvise1 was removed from linux in commit 303395ac3bf3e2cb488435537d416bc840438fcb 2011-11-11
microblaze:
__NR_fadvise, __NR_fstatat, __NR_pread, __NR_pwrite
had different name in linux.
mips:
__NR_fadvise, __NR_fstatat, __NR_pread, __NR_pwrite, __NR_select
had different name in linux.
mipsn32:
__NR_fstatat is called __NR_newfstatat in linux.
or1k:
__NR__llseek is called __NR_llseek in linux.
the old name is kept too because that's the name musl uses
internally.
powerpc:
__NR_{get,set}res{gid,uid}32 was never present in powerpc linux.
__NR_timerfd was briefly defined in linux but then got renamed.
This aligns clearenv with the Linux man page by setting 'environ'
rather than '*environ' to NULL, and stops it from leaking entries
allocated by the libc.
Rewrite environment access functions to slim down code, fix bugs and
avoid invoking undefined behavior.
* avoid using int-typed iterators where size_t would be correct;
* use strncmp instead of memcmp consistently;
* tighten prologues by invoking __strchrnul;
* handle NULL environ.
putenv:
* handle "=value" input via unsetenv too (will return -1/EINVAL);
* rewrite and simplify __putenv; fix the leak caused by failure to
deallocate entry added by preceding setenv when called from putenv.
setenv:
* move management of libc-allocated entries to this translation unit,
and use no-op weak symbols in putenv/unsetenv;
unsetenv:
* rewrite; this fixes UB caused by testing a free'd pointer against
NULL on entry to subsequent loops.
Not changed:
Failure to extend allocation tracking array (previously __env_map, now
env_alloced) is ignored rather than causing to report -1/ENOMEM to the
caller; the worst-case consequence is leaking this allocation when it
is removed or replaced in a subsequent environment access.
Initially UB in unsetenv was reported by Alexander Cherepanov.
Using a weak alias to avoid pulling in malloc via unsetenv was
suggested by Rich Felker.
fix erroneous acceptance of f4 9x xx xx code sequences by utf-8 decoder
the DFA table controlling accepted ranges for the f4 prefix used an
incorrect upper bound of 0xa0 where it should have been 0x90, allowing
such sequences to be accepted and decoded as non-Unicode-scalar values
0x110000 through 0x11ffff.
Rich Felker [Thu, 31 Aug 2017 18:30:28 +0000 (14:30 -0400)]
fix erroneous stop before input limit in mbsnrtowcs and wcsnrtombs
the value computed as an output limit that bounds the amount of input
consumed below the input limit was incorrectly being used as the
actual amount of input consumed. instead, compute the actual amount of
input consumed as a difference of pointers before and after the
conversion.
Szabolcs Nagy [Wed, 8 Feb 2017 00:31:56 +0000 (00:31 +0000)]
arm: add HWCAP_ARM_ hwcap macros
Glibc renamed the linux uapi HWCAP_* macros to HWCAP_ARM_*
so have both variants in case some code depends on it.
(The HWCAP2_ macros are not defined in glibc currently so those
only have the linux uapi variant.)
Szabolcs Nagy [Tue, 18 Apr 2017 22:20:54 +0000 (00:20 +0200)]
add a_clz_64 helper function
counts leading zero bits of a 64bit int, undefined on zero input.
(has nothing to do with atomics, added to atomic.h so target specific
helper functions are together.)
there is a logarithmic generic implementation and another in terms of
a 32bit a_clz_32 on targets where that's available.
It is possible for argv[0] to be a null pointer, but the __progname
variable is used to implement functions in src/legacy/err.c that do not
expect it to be null. It is also available to the user via the
program_invocation_name alias as a GNU extension, and the implementation
in Glibc initializes it to a pointer to empty string rather than NULL.
Since argv[0] is usually non-null and it's preferable to keep those
variables in BSS, implement the fallbacks in __init_libc, which also
allows to have an intermediate fallback to AT_EXECFN.
in musl the sockios macros are exposed in sys/ioctl.h together
with other ioctl requests instead of in sys/socket.h because of
namespace rules. (glibc has them in sys/socket.h under _GNU_SOURCE.)
Thomas Petazzoni [Fri, 28 Jul 2017 21:05:54 +0000 (23:05 +0200)]
fix build failure for sh4a due to missing colon in asm statement
Due to a missing ":" in an asm() statement, the "memory" clobber is
considered by gcc as an input operand and not a clobber, which causes a
build failure.
Rich Felker [Sat, 12 Aug 2017 00:42:30 +0000 (20:42 -0400)]
trap UB from attempts to join a detached thread
passing to pthread_join the id of a thread which is not joinable
results in undefined behavior.
in principle the check to trap does not necessarily work if
pthread_detach was called after thread creation, since no effort is
made here to synchronize access to t->detached, but the check is
well-defined and harmless for callers which did not invoke UB, and
likely to help catch erroneous code that would otherwise mysteriously
hang.
Bobby Bingham [Fri, 4 Aug 2017 05:12:32 +0000 (00:12 -0500)]
ppc64: fix setjmp/longjmp handling of TOC pointer
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.
Rich Felker [Fri, 11 Aug 2017 04:17:00 +0000 (00:17 -0400)]
disable global visibility override hack (vis.h) by default
neither current compilers nor linkers treat protected visibility the
way I expected, as having fixed source-level semantics rather than
being dependent on target-specific ABI details, and change seems
unlikely. while the use here does not actually depend on the specific
semantics, at least some versions of some linkers, especially lld,
refuse to allow linking to a libc.so where the symbols have protected
visibility. this cannot be detected at configure-time because linking
libc.so itself works fine, and because even if we could test linking
an application against libc.so successfully, we could not justifiably
assume that the same linker used to link libc.so would also be used
later to link applications.
disable the vis.h hack by default at the configure level, but add an
explicit "auto" option to request the old configure-time detection
rather than just removing it. this leaves it easy to evaluate whether
it actually resulted in significant size or performance benefits while
ensuring that out-of-the-box builds are not unlinkable for some users.
fortunately, preliminary evaluation suggests that at least x86_64,
arm, and aarch64 don't suffer at all from the change, and impact on
other archs is low. if low is not low enough, it should not be hard to
analyze where the significant PLT call ABI costs are present and
mitigate them without the hack.
Rich Felker [Tue, 1 Aug 2017 03:08:27 +0000 (23:08 -0400)]
add _NL_LOCALE_NAME extension to nl_langinfo
since setlocale(cat, NULL) is required to return the setting for the
global locale, there is no standard mechanism to obtain the name of
the currently active thread-local locale set by uselocale. this makes
it impossible for application/library software to load appropriate
translations, etc. unless using the gettext implementation provided by
libc, which has privileged access to libc internals.
to fill this gap, glibc introduced the _NL_LOCALE_NAME macro which can
be used with nl_langinfo to obtain the name. GNU gettext/gnulib code
already use this functionality on glibc, and can easily be adapted to
make use of it on non-glibc systems if it's available; for other
systems they poke at locale implementation internals, which we want to
avoid. this patch provides a compatible interface to the one glibc
introduced.
The switch statement has no 'default:' case and the function ends
immediately following the switch, so the extra comparison did not
communicate any extra information to the compiler.
Jens Gustedt [Sat, 24 Jun 2017 08:18:05 +0000 (10:18 +0200)]
unify the use of FUTEX_PRIVATE
The flag 1<<7 is used in several places for different purposes that are
not always easy to distinguish. Mark those usages that correspond to the
flag that is used by the kernel for futexes.
allow specifying argv[0] when invoking a program via ldso command
previously, the pathname used to load the program was always used as
argv[0]. the default remains the same, but a new --argv0 option can be
used to provide a different value.
ldso: avoid spurious & possible erroneous work for libs with no deps
a null pointer for a library's deps list was ambiguous: it could
indicate either no dependencies or that the dependency list had not
yet been populated. inability to distinguish could lead to spurious
work when dlopen is called multiple times on a library with no deps,
and due to related bugs, could actually cause other libraries to
falsely appear as dependencies, translating into false positives for
dlsym.
avoid the problem by always initializing the deps pointer, pointing to
an empty list if there are no deps. rather than wasting memory and
introducing another failure path by allocating an empty list per
library, simply share a global dummy list.
further fixes will be needed for related bugs, and much of this code
may end up being replaced.
Rich Felker [Fri, 23 Jun 2017 20:01:00 +0000 (16:01 -0400)]
powerpc64: add single-instruction math functions
while the official elfv2 abi for "powerpc64le" sets power8 as the
baseline isa, we use it for both little and big endian powerpc64
targets and need to maintain compatibility with pre-power8 models. the
instructions for sqrt, fabs, and fma are in the baseline isa; support
for the rest is conditional via predefined isa-level macros.
Rich Felker [Fri, 23 Jun 2017 19:28:10 +0000 (15:28 -0400)]
s390x: add single-instruction math functions
these were introduced in z196 and not available in the baseline (z900)
ISA level. use __HTM__ as an alternate indicator for ISA level, since
gcc did not define __ARCH__ until 7.x.
Szabolcs Nagy [Tue, 21 Feb 2017 00:07:34 +0000 (00:07 +0000)]
fix arm run-time abi string functions
in arm rtabi these __aeabi_* functions have special abi (they are
only allowed to clobber r0,r1,r2,r3,ip,lr,cpsr), so they cannot
be simple wrappers around normal string functions (which may
clobber other registers), the safest solution is to write them in
asm, a minimalistic implementation works because these are not
supposed to be emitted by compilers or used in general.
commit 97bd6b09dbe7478d5a90a06ecd9e5b59389d8eb9 refactored the table
lookup into a function and introduced an error in index computation.
the error caused garbage to be read from the table if the given charmap
had a non-zero number of elided entries.
Rich Felker [Thu, 15 Jun 2017 17:01:34 +0000 (13:01 -0400)]
set errno when getpw*_r, getgr*_r, and getspnam_r fail
these functions return an error code, and are not explicitly
documented to set errno, but they are nonstandard and the historical
implementations do set errno as well, and some applications expect
this behavior. do likewise for compatibility.
Rich Felker [Thu, 15 Jun 2017 16:58:08 +0000 (12:58 -0400)]
handle localtime errors in ctime
ctime passes the result from localtime directly to asctime. But in case
of error, localtime returns 0. This causes an error (NULL pointer
dereference) in asctime.
Rich Felker [Thu, 15 Jun 2017 16:54:40 +0000 (12:54 -0400)]
handle mremap failure in realloc of mmap-serviced allocations
mremap seems to always fail on nommu, and on some non-Linux
implementations of the Linux syscall API, it at least fails to
increase allocation size, and may fail to move (i.e. defragment) the
existing mapping when shrinking it too. instead of failing realloc or
leaving an over-sized allocation that may waste a large amount of
memory, fallback to malloc-memcpy-free if mremap fails.
Rich Felker [Thu, 8 Jun 2017 23:50:23 +0000 (19:50 -0400)]
fix glob failure to match plain "/" to root directory
the check to prevent matching empty string wrongly blocked matching
of "/" due to checking emptiness after stripping leading slashes
rather than checking the full original argument string.
Rich Felker [Thu, 8 Jun 2017 23:44:27 +0000 (19:44 -0400)]
use hard-coded sh4a atomic opcodes to avoid linker errors on sh
when using the sh4a opcodes, the assembler tags the resulting object
file as requiring sh4a. the linker then refuses to (static) link it
with object files marked as requiring j2, since there is no isa level
that includes both sh4a and j2 instructions.
Rich Felker [Thu, 1 Jun 2017 01:49:44 +0000 (21:49 -0400)]
remove long-obsolete clang workarounds from mips* syscall_arch.h files
at one point, clang reportedly failed to support the asm register
constraints needed for inline syscalls. versions of clang that old
have much bigger problems that preclude using them to compile musl
libc.
Rich Felker [Thu, 1 Jun 2017 01:46:15 +0000 (21:46 -0400)]
fix fstatat syscall on mips64
mips64 requires 'struct stat' conversion due to incorrect 32-bit
fields where time_t should be in the kernel version of the structure.
syscall_arch.h already performed the correct translation for stat,
fstat, and lstat syscalls, but omitted special handling for fstatat.
Samuel Holland [Sat, 27 May 2017 20:20:01 +0000 (15:20 -0500)]
fix fchown fallback on arches without chown(2)
The flags argument was missing, causing uninitalized data to be passed
to fchownat(2). The correct value of flags should match the fallback for
chown(3).
Rich Felker [Sun, 28 May 2017 01:36:00 +0000 (21:36 -0400)]
fix iconv conversions to legacy 8bit encodings
there was missing reverse-conversion logic for the case, handled
specially in the character set tables, where a byte represents a
unicode codepoint with the same value.
this patch adds code to handle the case, and refactors the two-level
10-bit table lookup for legacy character sets into a function to avoid
repeating it yet another time as part of the fix.
have posix_spawnattr_setflags check for supported flags
per POSIX, EINVAL is not a mandatory error, only an optional one. but
reporting unsupported flags allows an application to fallback
gracefully when a requested feature is not supported. this is not
helpful now, but it may be in the future if additional flags are
added.
had this checking been present before, applications would have been
able to check for the newly-added POSIX_SPAWN_SETSID feature (added in
commit bb439bb17108b67f3df9c9af824d3a607b5b059d) at runtime.
the bit is reserved anyway for ABI-compat reasons; this documents it
and makes it so we can have posix_spawnattr_setflags check for flag
validity without hard-coding an anonymous bit value.
remove va_arg hacks in printf core with undefined behavior
the code being removed was written to optimize for size assuming the
compiler cannot collapse code paths for different types with the same
underlying representation. modern compilers sometimes succeed in
making this optimization themselves, but either way it's a small size
difference and not worth the source-level complexity or the UB
involved in this hack.
some incorrect use of va_arg still remains, particularly use of void *
where the actual argument has a different pointer type. fixing this
requires some actual code additions, rather than just removing cruft,
so I'm leaving it to be done later as a separate commit.
commit 0a950dcf15bb9f7274c804dca490e9e20e475f3e added checking that
the pathname a tty device was opened with actually matches the device,
which can fail to hold when a container inherits a tty from outside
the container. the error code added at the time was ENOENT; however,
discussions between affected applications and glibc developers
resulted in glibc adopting ENODEV as the error for this condition, and
this has now been documented in the man pages project as well. adopt
the same error code for consistency.
fix regression in support for resolv.conf attempts option
commit d6cb08bcaca4ff1f921375510ca72bccea969c75 moved the code and
introduced an incorrect string offset for the new parsing, probably
due to a copy-and-paste error.
projects / musl / log