the duplicate code in dn_expand and its incorrect return values are
both results of the history of the code: the version in __dns.c was
originally written with no awareness of the legacy resolver API, and
was later copy-and-paste duplicated to provide the legacy API.
this commit is the first of a series that will restructure the
internal dns code to share as much code as possible with the legacy
resolver API functions.
I have also removed the loop detection logic, since the output buffer
length limit naturally prevents loops. in order to avoid long runtime
when encountering a loop if the caller provided a ridiculously long
buffer, the caller-provided length is clamped at the maximum dns name
length.
these aliases were originally intended to be for ABI compatibility
only, but their presence caused regressions in broken gnulib-based
software whose configure scripts detect the existing of these
functions then use them without declarations, resulting in bogus
return values.
mips has signal numbers up to 127 (formerly, up to 128, but the last
one never worked right and caused kernel panic when used), so 127 in
the "signal number" field of the wait status is insufficient for
determining that the process was stopped. in addition, a nonzero value
in the upper bits must be present, indicating the signal number which
caused the process to be stopped.
details on this issue can be seen in the email with message id
CAAG0J9-d4BfEhbQovFqUAJ3QoOuXScrpsY1y95PrEPxA5DWedQ@mail.gmail.com on
the linux-mips mailing list, archived at:
http://www.linux-mips.org/archives/linux-mips/2013-06/msg00552.html
and in the associated thread about fixing the mips kernel bug.
commit 4a96b948687166da26a6c327e6c6733ad2336c5c fixed the
corresponding issue in uClibc, but introduced a multiple-evaluation
issue for the WIFSTOPPED macro.
for the most part, none of these issues affected pure musl systems,
since musl has up until now (incorrectly) defined SIGRTMAX as 64 on
all archs, even mips. however, interpreting status of non-musl
programs on mips may have caused problems. with this change, the full
range of signal numbers can be made available on mips.
this first commit just includes the CPU_* and sched_* interfaces, not
the pthread_* interfaces, which may be added later. simple
sanity-check testing has been done for the basic interfaces, but most
of the macros have not yet been tested.
also add a warning to the existing sys/poll.h. the warning is absent
from sys/dir.h because it is actually providing a slightly different
API to the program, and thus just replacing the #include directive is
not a valid fix to programs using this one.
apparently the original kernel commit's i386 version of siginfo.h
defined this field as unsigned int, but the asm-generic file always
had void *. unsigned int is obviously not a suitable type for an
address, in a non-arch-specific file, and glibc also has void * here,
so I think void * is the right type for it.
also fix redundant type specifiers.
linux commit 8d36eb01da5d371feffa280e501377b5c450f5a5 (2013-05-29)
added PF_IB for InfiniBand
linux commit d021c344051af91f42c5ba9fdedc176740cbd238 (2013-02-06)
added PF_VSOCK for VMware sockets
linux commit a0727e8ce513fe6890416da960181ceb10fbfae6 (2012-04-12)
added siginfo fields for SIGSYS (seccomp uses it)
linux commit ad5fa913991e9e0f122b021e882b0d50051fbdbc (2009-09-16)
added siginfo field and si_code values for SIGBUS (hwpoison signal)
this is necessary to meet the C++ ABI target. alternatives were
considered to avoid the size increase for non-sig jmp_buf objects, but
they seemed to have worse properties. moreover, the relative size
increase is only extreme on x86[_64]; one way of interpreting this is
that, if the size increase from this patch makes jmp_buf use too much
memory, then the program was already using too much memory when built
for non-x86 archs.
this patch is something of a compromise for a compatibility
regression discovered after the header refactoring: libtiff uses
_Int64 for its own use. this is absolutely wrong, invalid C, and
should not be supported, but it's also frustrating for users when code
that used to work suddenly breaks.
rather than leave the breakage in place or change musl internals to
accommodate broken software, I've found a change that makes the
problem go away and improves musl. by undefining these macros at the
end of alltypes.h, the temptation to use them in other headers is
removed. (for example, I almost used _Int64 in sys/types.h to define
u_int64_t rather than adding it back to alltypes.h.) by confining use
of these macros to alltypes.h, we keep it easy to go back and change
the implementation of alltypes later, if needed.
during the header refactoring, I had moved u_int64_t out of alltypes
under the assumption that we could just use long long everywhere.
however, it seems some broken applications make inconsistent mixed use
of u_int64_t and uint64_t, resulting in build errors when the
underlying type differs.
rather than moving nlink_t back to the arch-specific file, I've added
a macro _Reg defined to the canonical type for register-size values on
the arch. this is not the same as _Addr for (not-yet-supported)
32-on-64 pseudo-archs like x32 and mips n32, so a new macro was
needed.
for regoff_t, it's impossible to match on 64-bit archs because glibc
defined the type in a non-conforming way. however this change makes
the type match on 32-bit archs.
aside from the obvious C++ ABI purpose for this change, it also brings
musl into alignment with the compiler's idea of the definition of
wint_t (use in -Wformat), and makes the situation less awkward on ARM,
where wchar_t is unsigned.
internal code using wint_t and WEOF was checked against this change,
and while a few cases of storing WEOF into wchar_t were found, they
all seem to operate properly with the natural conversion from unsigned
to signed.
the arch-specific bits/alltypes.h.sh has been replaced with a generic
alltypes.h.in and minimal arch-specific bits/alltypes.h.in.
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
while there's no POSIX namespace provision for UIO_* in uio.h, this
exact macro name is reserved in XBD 2.2.2. apparently some
glibc-centric software expects it to exist, so let's provide it.
POSIX is not clear on whether it includes the termination, but ISO C
requires that it does. the whole concept of this macro is rather
useless, but it's better to be correct anyway.
the main use for this macro seems to be knowing the correct allocation
granularity for dynamic-sized fd_set objects. such usage is
non-conforming and results in undefined behavior, but it is widespread
in applications.
a research in debian codesearch and grepping over the pkgsrc
directory tree have shown that these macros are all either unused,
or defined by programs in case they need them.
these would not be expensive to actually implement, but reading
/etc/ethers does not sound like a particularly useful feature, so for
now I'm leaving them as stubs.
in theory this should not be an issue, since major() should only be
applied to type dev_t, which is 64-bit. however, it appears some
applications are not using dev_t but a smaller integer type (which
works on Linux because the kernel's dev_t is really only 32-bit). to
avoid the undefined behavior, do it as two shifts.
rejecting invalid values for n is fine even in the case where a new
sem will not be created, since the kernel does its range checks on n
even in this case as well.
by default, the kernel will bound the limit well below USHRT_MAX
anyway, but it's presumably possible that an administrator could
override this limit and break things.
this type is not really intended to be used; it's just there to allow
implementations to choose the type for the shm_nattch member of
struct shmid_sh, presumably since historical implementations disagreed
on the type. in any case, it needs to be there, so now it is.
the pathnames prefixed with /dev/null/ are guaranteed never to be
valid. the previous use of /dev/null alone was mildly dangerous in
that bad software might attempt to unlink the name when it found a
non-regular file there and create a new file.
despite declaring functions that take arguments of type va_list, these
headers are not permitted by the c standard to expose the definition
of va_list, so an alias for the type must be used. the name
__isoc_va_list was chosen to convey that the purpose of this alternate
name is for iso c conformance, and to avoid the multitude of names
which gcc mangles with its hideous "fixincludes" monstrosity, leading
to serious header breakage if these "fixes" are run.
Rich Felker
rofl0r
Szabolcs Nagy