Szabolcs Nagy [Sun, 8 Jul 2018 13:16:54 +0000 (15:16 +0200)]
add support for arch-specific ptrace command macros
sys/ptrace.h is target specific, use bits/ptrace.h to add target
specific macro definitions.
these macros are kept in the generic sys/ptrace.h even though some
targets don't support them:
PTRACE_GETREGS
PTRACE_SETREGS
PTRACE_GETFPREGS
PTRACE_SETFPREGS
PTRACE_GETFPXREGS
PTRACE_SETFPXREGS
so no macro definition got removed in this patch on any target. only
s390x has a numerically conflicting macro definition (PTRACE_SINGLEBLOCK).
the PT_ aliases follow glibc headers, otherwise the definitions come
from linux uapi headers except ones that are skipped in glibc and
there is no real kernel support (s390x PTRACE_*_AREA) or need special
type definitions (mips PTRACE_*_WATCH_*) or only relevant for linux
2.4 compatibility (PTRACE_OLDSETOPTIONS).
Szabolcs Nagy [Sun, 8 Jul 2018 13:15:06 +0000 (15:15 +0200)]
sys/ptrace.h: add missing PTRACE_EVENT_STOP
new in linux v3.1 commit
3544d72a0e10d0aa1c1bd59ed77a53a59cdc12f7
changed in linux v3.4 commit
5cdf389aee90109e2e3d88085dea4dd5508a3be7
A tracer recieves this event in the waitpid status of a PTRACED_SEIZED
process.
Szabolcs Nagy [Sun, 8 Jul 2018 13:19:03 +0000 (15:19 +0200)]
uchar.h: define char16_t and char32_t for old c++
including uchar.h in c++ code is only well defined in c++11 onwards
where char16_t and char32_t type definitions must be hidden since they
are keywords. however some c++ code compiled for older c++ standard
include uchar.h too and they need the typedefs, this fix makes such
code work.
Rich Felker [Mon, 16 Jul 2018 16:32:57 +0000 (12:32 -0400)]
block dlopen of libraries with initial-exec refs to dynamic TLS
previously, this operation succeeded, and the relocation results
worked for access from new threads created after dlopen, but produced
invalid accesses (and possibly clobbered other memory) from threads
that already existed.
the way the check is written, it still permits dlopen of libraries
containing initial-exec references to static TLS (TLS in the main
program or in a dynamic library loaded at startup).
Rich Felker [Mon, 16 Jul 2018 16:29:14 +0000 (12:29 -0400)]
fix inefficient choice of tlsdesc function due to off-by-one
tls_id is one-based, whereas [static_]tls_cnt is a count, so
comparison for checking that a given tls_id is dynamic rather than
static needs to use strict inequality.
Rich Felker [Sun, 15 Jul 2018 00:20:19 +0000 (20:20 -0400)]
implement getaddrinfo's AI_ADDRCONFIG flag
this flag is notoriously under-/mis-specified, and in the past it was
implemented as a nop, essentially considering the absence of a
loopback interface with 127.0.0.1 and ::1 addresses an unsupported
configuration. however, common real-world container environments omit
IPv6 support (even for the network-namespaced loopback interface), and
some kernels omit IPv6 support entirely. future systems on the other
hand might omit IPv4 entirely.
treat these as supported configurations and suppress results of the
unconfigured/unsupported address families when AI_ADDRCONFIG is
requested. use routability of the loopback address to make the
determination; unlike other implementations, we do not exclude
loopback from the "an address is configured" condition, since there is
no basis in the specification for such exclusion. obtaining a result
with AI_ADDRCONFIG does not imply routability of the result, and
applications must still be able to cope with unroutable results even
if they pass AI_ADDRCONFIG.
Rich Felker [Sat, 14 Jul 2018 01:56:27 +0000 (21:56 -0400)]
fix writes outside buffer by ungetc after setvbuf
commit
0b80a7b0404b6e49b0b724e3e3fe0ed5af3b08ef, which added non-stub
setvbuf, applied the UNGET pushback adjustment to the size of the
buffer passed in, but inadvertently omitted offsetting the start by
the same amount, thereby allowing unget to clobber up to 8 bytes
before the start of the buffer. this bug was introduced in the present
release cycle; no releases are affected.
Rich Felker [Fri, 13 Jul 2018 00:41:30 +0000 (20:41 -0400)]
add ST_RELATIME to statvfs.h
Rich Felker [Wed, 11 Jul 2018 19:03:34 +0000 (15:03 -0400)]
resolver: don't depend on v4mapped ipv6 to probe routability of v4 addrs
to produce sorted results roughly corresponding to RFC 3484/6724,
__lookup_name computes routability and choice of source address via
dummy UDP connect operations (which do not produce any packets). since
at the logical level, the properties fed into the sort key are
computed on ipv6 addresses, the code was written to use the v4mapped
ipv6 form of ipv4 addresses and share a common code path for them all.
however, on kernels where ipv6 support has been completely omitted,
this causes ipv4 to appear equally unroutable as ipv6, thereby putting
unreachable ipv6 addresses before ipv4 addresses in the results.
instead, use only ipv4 sockets to compute routability for ipv4
addresses. some gratuitous conversion back and forth is left so that
the logic is not affected by these changes. it may be possible to
simplify the ipv4 case considerably, thereby reducing code size and
complexity.
Alexander Monakov [Thu, 28 Jun 2018 17:57:29 +0000 (20:57 +0300)]
optimize explicit_bzero for size
Avoid saving/restoring the incoming argument by reusing memset return
value.
Rich Felker [Thu, 28 Jun 2018 16:20:58 +0000 (12:20 -0400)]
avoid spurious dso matches by dladdr outside bounds of load segments
since slack space at the beginning and/or end of writable load maps is
donated to malloc, the application could obtain valid pointers in
these ranges which dladdr would erroneously identify as part of the
shared object whose mapping they came from.
instead of checking the queried address against the mapping base and
length, check it against the load segments from the program headers,
and only match the dso if it lies within the bounds of one of them.
as a shortcut, if the address does match the range of the mapping but
not any of the load segments, we know it cannot match any other dso
and can immediately return failure.
Rich Felker [Thu, 28 Jun 2018 16:07:51 +0000 (12:07 -0400)]
make dladdr consistently produce the first symbol in presence of aliases
the early-exit condition for the symbol match loop on exact matches
caused dladdr to produce the first match for an exact match, but the
last match for an inexact match. in the interest of consistency,
require a strictly-closer match to replace an already-found one.
Rich Felker [Thu, 28 Jun 2018 15:51:43 +0000 (11:51 -0400)]
fix symtab-order-dependent spurious matches in dladdr
commit
8b8fb7f03721c42445f982582f462144ab60a1a0 added logic to prevent
matching a symbol with no recorded size (closest-match) when there is
an intervening symbol whose size was recorded, but it only worked when
the intervening symbol was encountered later in the search.
instead of rejecting symbols where addr falls outside their recorded
size during the closest-match search, accept them to find the true
closest-match, then reject such a result only once the search has
finished.
Rich Felker [Wed, 27 Jun 2018 19:32:09 +0000 (15:32 -0400)]
correctly handle non-matching symbols in dladdr
based on patch by Axel Siebenborn, with fixes discussed on the mailing
list after submission and and rebased around the UB fix in commit
e829695fcc880f8578c2b964ea2d090f0016c9d7.
avoid spurious symbol matches by dladdr beyond symbol size. for
symbols with a size recorded, only match if the queried address lies
within the address range determined by the symbol address and size.
for symbols with no size recorded, the old closest-match behavior is
kept, as long as there is no intervening symbol with a recorded size.
the case where no symbol is matched, but the address does lie within
the memory range of a shared object, is specified as success. fix the
return value and produce a valid (with null dli_sname and dli_saddr)
Dl_info structure.
Rich Felker [Wed, 27 Jun 2018 19:29:12 +0000 (15:29 -0400)]
avoid using undefined pointer arithmetic in dladdr
Patrick Oppenlander [Fri, 1 Jun 2018 00:49:20 +0000 (10:49 +1000)]
fix missing timeout argument to futex syscall in __futexwait
David Carlier [Fri, 15 Jun 2018 13:30:09 +0000 (13:30 +0000)]
add explicit_bzero implementation
maintainer's note: past sentiment was that, despite being imperfect
and unable to force clearing of all possible copies of sensitive data
(e.g. in registers, register spills, signal contexts left on the
stack, etc.) this function would be added if major implementations
agreed on it, which has happened -- several BSDs and glibc all include
it.
Arthur Jones [Tue, 5 Jun 2018 23:51:27 +0000 (16:51 -0700)]
inet_ntop: do not compress single zeros in IPv6
maintainer's note: this change is for conformance with RFC 5952,
4.2.2, which explicitly forbids use of :: to shorten a single 16-bit 0
field when producing the canonical text representation for an IPv6
address. fixes a test failure reported by Philip Homburg, who also
submitted a patch, but this fix is simpler and should produce smaller
code.
Daniel Sabogal [Mon, 11 Jun 2018 17:15:15 +0000 (13:15 -0400)]
strftime: fix underlying format string in %z format
the expression (tm->__tm_gmtoff)/3600 has type long. use %+.2ld instead.
Rich Felker [Tue, 26 Jun 2018 20:17:05 +0000 (16:17 -0400)]
resolver: omit final dot (root/suppress-search) in canonical name
if a final dot was included in the queried host name to anchor it to
the dns root/suppress search domains, and the result was not a CNAME,
the returned canonical name included the final dot. this was not
consistent with other implementations, confused some applications, and
does not seem desirable.
POSIX specifies returning a pointer to, or to a copy of, the input
nodename, when the canonical name is not available, but does not
attempt to specify what constitutes "not available". in the case of
search, we already have an implementation-defined "availability" of a
canonical name as the fully-qualified name resulting from search, so
defining it similarly in the no-search case seems reasonable in
addition to being consistent with other implementations.
as a bonus, fix the case where more than one trailing dot is included,
since otherwise the changes made here would wrongly cause lookups with
two trailing dots to succeed. previously this case resulted in
malformed dns queries and produced EAI_AGAIN after a timeout. now it
fails immediately with EAI_NONAME.
Rich Felker [Tue, 26 Jun 2018 20:28:49 +0000 (16:28 -0400)]
fix regression in powerpc[64] SO_PEERSEC definition
commit
587f5a53bc3a68d80b239ba515d583df690a96df moved the definition
of SO_PEERSEC to bits/socket.h for archs where the SO_* macros differ
from their standard values, but failed to add copies of the generic
definition for powerpc and powerpc64.
Rich Felker [Tue, 26 Jun 2018 19:55:29 +0000 (15:55 -0400)]
fix value of SO_PEERSEC on mips archs
adapted from patch by Matthias Schiffer.
Rich Felker [Tue, 26 Jun 2018 16:30:23 +0000 (12:30 -0400)]
add m68k reg.h and user.h
Rich Felker [Tue, 26 Jun 2018 16:15:13 +0000 (12:15 -0400)]
fix dynamic linker mapping/clearing bss in first/only LOAD segment
writable load segments can have size-in-memory larger than their size
in the ELF file, representing bss or equivalent. the initial partial
page has to be zero-filled, and additional anonymous pages have to be
mapped such that accesses don't failt with SIGBUS.
map_library skips redundant MAP_FIXED mapping of the initial
(lowest-address) segment when processing LOAD segments since it was
already mapped when reserving the virtual address range, but in doing
so, inadvertently also skipped the code to fill/map bss. typical
executable and library files have two or more LOAD segments, and the
first one is text/rodata (non-writable) and thus has no bss, but it is
syntactically valid for an ELF program/library to put its writable
segment first, or to have only one segment (everything writable). the
binutils bfd-based linker has been observed to create such programs in
the presence of unusual sections or linker scripts.
fix by moving only the mmap_fixed operation under the conditional
rather than skipping the remainder of the loop body. add a check to
avoid bss processing in the case where the segment is not writable;
this should not happen, but if it does, the change would be a crashing
regression without this check.
Szabolcs Nagy [Tue, 19 Jun 2018 20:28:03 +0000 (20:28 +0000)]
add memfd_create syscall wrapper
memfd_create was added in linux v3.17 and glibc has api for it.
Szabolcs Nagy [Sat, 28 Apr 2018 17:25:41 +0000 (17:25 +0000)]
add mlock2 linux syscall wrapper
mlock2 syscall was added in linux v4.4 and glibc has api for it.
It falls back to mlock in case of flags==0, so that case works
even on older kernels.
MLOCK_ONFAULT is moved under _GNU_SOURCE following glibc.
Rich Felker [Wed, 20 Jun 2018 19:28:49 +0000 (15:28 -0400)]
fix m68k float.h long double exponent range
unlike the x86 variant, the m68k ld80 format allows (biased) exponent
zero with mantissa msb set, thereby extending the normal range.
Rich Felker [Wed, 20 Jun 2018 04:07:09 +0000 (00:07 -0400)]
work around broken kernel struct ipc_perm on some big endian archs
the mode member of struct ipc_perm is specified by POSIX to have type
mode_t, which is uniformly defined as unsigned int. however, Linux
defines it with type __kernel_mode_t, and defines __kernel_mode_t as
unsigned short on some archs. since there is a subsequent padding
field, treating it as a 32-bit unsigned int works on little endian
archs, but the order is backwards on big endian archs with the
erroneous definition.
since multiple archs are affected, remedy the situation with fixup
code in the affected functions (shmctl, semctl, and msgctl) rather
than repeating the same shims in syscall_arch.h for every affected
arch.
Szabolcs Nagy [Sat, 9 Jun 2018 23:03:48 +0000 (23:03 +0000)]
s390x: add kexec_file_load syscall number from linux v4.17
new in linux commit
71406883fd35794d573b3085433c41d0a3bf6c21
Szabolcs Nagy [Sat, 9 Jun 2018 22:58:19 +0000 (22:58 +0000)]
mips: add HWCAP_ flags from linux v4.17
new in linux commit
256211f2b0b251e532d1899b115e374feb16fa7a
Szabolcs Nagy [Sat, 9 Jun 2018 22:51:08 +0000 (22:51 +0000)]
aarch64: add HWCAP_ flags from linux v4.17
hwcaps for armv8.4, new in linux commit
7206dc93a58fb76421c4411eefa3c003337bcb2d
Szabolcs Nagy [Sat, 9 Jun 2018 21:23:54 +0000 (21:23 +0000)]
add speculation control prctls from linux v4.17
PR_{SET,GET}_SPECULATION_CTRL controls speculation related vulnerability
mitigations, new in commits
b617cfc858161140d69cc0b5cc211996b557a1c7
356e4bfff2c5489e016fdb925adbf12a1e3950ee
Szabolcs Nagy [Sat, 9 Jun 2018 21:20:45 +0000 (21:20 +0000)]
add ETH_P_PREAUTH ethertype from linux v4.17
added in linux commit
4fe0de5b143762d327bfaf1d7be7c5b58041a18c
Szabolcs Nagy [Sat, 9 Jun 2018 21:15:13 +0000 (21:15 +0000)]
add TCP_NLA_* from linux v4.17
new and missing netlink attributes types for SCM_TIMESTAMPING_OPT_STATS,
new ones were added in commits
7156d194a0772f733865267e7207e0b08f81b02b
be631892948060f44b1ceee3132be1266932071e
87ecc95d81d951b0984f2eb9c5c118cb68d0dce8
Szabolcs Nagy [Sat, 9 Jun 2018 21:06:58 +0000 (21:06 +0000)]
add {MSG,SEM,SHM}_STAT_ANY from linux v4.17
introduced to stat ipc objects without permission checks since the
info is available in /proc/sysvipc anyway, new in linux commits
23c8cec8cf679b10997a512abb1e86f0cedc42ba
a280d6dc77eb6002f269d58cd47c7c7e69b617b6
c21a6970ae727839a2f300cd8dd957de0d0238c3
Szabolcs Nagy [Sat, 9 Jun 2018 20:39:35 +0000 (20:39 +0000)]
add MAP_FIXED_NOREPLACE from linux v4.17
to map at a fixed address without unmapping underlying mappings
(fails with EEXIST unlike MAP_FIXED), new in linux commits
4ed28639519c7bad5f518e70b3284c6e0763e650 and
a4ff8e8620d3f4f50ac4b41e8067b7d395056843.
Szabolcs Nagy [Sat, 28 Apr 2018 16:36:40 +0000 (16:36 +0000)]
powerpc: add pkey syscall numbers from linux v4.16
add pkey_mprotect, pkey_alloc, pkey_free syscall numbers,
new in linux commits
3350eb2ea127978319ced883523d828046af4045
and
9499ec1b5e82321829e1c1510bcc37edc20b6f38
Szabolcs Nagy [Sat, 28 Apr 2018 16:29:55 +0000 (16:29 +0000)]
aarch64: add HWCAP_ASIMDFHM from linux v4.16
armv8.4 fp mul instructions.
added in commit
3b3b681097fae73b7f5dcdd42db6cfdf32943d4c
Szabolcs Nagy [Sat, 28 Apr 2018 16:23:23 +0000 (16:23 +0000)]
sys/ptrace.h: add PTRACE_SECCOMP_GET_METADATA from linux v4.16
to get seccomp state for checkpoint restore.
added in linux commit
26500475ac1b499d8636ff281311d633909f5d20
struct tag follows the glibc api and ptrace_peeksiginfo_args
got changed too accordingly.
Szabolcs Nagy [Sat, 28 Apr 2018 16:16:12 +0000 (16:16 +0000)]
netinet/if_ether.h: add ETH_TLEN from linux v4.16
octets in ethernet type field
added in linux commit
4bbb3e0e8239f9079bf1fe20b3c0cb598714ae61
Szabolcs Nagy [Sat, 28 Apr 2018 16:10:53 +0000 (16:10 +0000)]
netinet/if_ether.h: add ETH_P_ERSPAN2 from linux v4.16
protocol number for erspan v2 support
added in linux commit
f551c91de262ba36b20c3ac19538afb4f4507441
Szabolcs Nagy [Sat, 28 Apr 2018 15:52:06 +0000 (15:52 +0000)]
sys/epoll.h: add EPOLLNVAL from linux v4.16
added to uapi in commit
65aaf87b3aa2d049c6b9fd85221858a895df3393
used since commit
a9a08845e9acbd224e4ee466f5c1275ed50054e8,
which renamed POLL* to EPOLL* in the kernel.
Rich Felker [Thu, 14 Jun 2018 18:26:30 +0000 (14:26 -0400)]
add m68k port
three ABIs are supported: the default with 68881 80-bit fpu format and
results returned in floating point registers, softfloat-only with the
same format, and coldfire fpu with IEEE single/double only. only the
first is tested at all, and only under qemu which has fpu emulation
bugs.
basic functionality smoke tests have been performed for the most
common arch-specific breakage via libc-test and qemu user-level
emulation. some sysvipc failures remain, but are shared with other big
endian archs and will be fixed separately.
Rich Felker [Thu, 14 Jun 2018 15:00:58 +0000 (11:00 -0400)]
add support for m68k 80-bit long double variant
since x86 and m68k are the only archs with 80-bit long double and each
has mandatory endianness, select the variant via endianness.
differences are minor: apparently just byte order and representation
of infinities. the m68k format is not well-documented anywhere I could
find, so if other differences are found they may require additional
changes later.
Rich Felker [Tue, 12 Jun 2018 21:02:21 +0000 (17:02 -0400)]
add missing m68k relocation types in elf.h
Szabolcs Nagy [Fri, 1 Jun 2018 23:52:01 +0000 (01:52 +0200)]
fix TLS layout of TLS variant I when there is a gap above TP
In TLS variant I the TLS is above TP (or above a fixed offset from TP)
but on some targets there is a reserved gap above TP before TLS starts.
This matters for the local-exec tls access model when the offsets of
TLS variables from the TP are hard coded by the linker into the
executable, so the libc must compute these offsets the same way as the
linker. The tls offset of the main module has to be
alignup(GAP_ABOVE_TP, main_tls_align).
If there is no TLS in the main module then the gap can be ignored
since musl does not use it and the tls access models of shared
libraries are not affected.
The previous setup only worked if (tls_align & -GAP_ABOVE_TP) == 0
(i.e. TLS did not require large alignment) because the gap was
treated as a fixed offset from TP. Now the TP points at the end
of the pthread struct (which is aligned) and there is a gap above
it (which may also need alignment).
The fix required changing TP_ADJ and __pthread_self on affected
targets (aarch64, arm and sh) and in the tlsdesc asm the offset to
access the dtv changed too.
Rich Felker [Sat, 2 Jun 2018 02:05:48 +0000 (22:05 -0400)]
fix output size handling for multi-unicode-char big5-hkscs characters
since this iconv implementation's output is stateless, it's necessary
to know before writing anything to the output buffer whether the
conversion of the current input character will fit.
previously we used a hard-coded table of the output size needed for
each supported output encoding, but failed to update the table when
adding support for conversion to jis-based encodings and again when
adding separate encoding identifiers for implicit-endianness utf-16/32
and ucs-2/4 variants, resulting in out-of-bound table reads and
incorrect size checks. no buffer overflow was possible, but the
affected characters could be converted incorrectly, and iconv could
potentially produce an incorrect return value as a result.
remove the hard-coded table, and instead perform the recursive iconv
conversion to a temporary buffer, measuring the output size and
transferring it to the actual output buffer only if the whole
converted result fits.
Rich Felker [Sat, 2 Jun 2018 01:50:17 +0000 (21:50 -0400)]
fix iconv mapping of big5-hkscs characters that map to two unicode chars
this case is handled with a recursive call to iconv using a
specially-constructed conversion descriptor. the constant 0 was used
as the offset for utf-8, since utf-8 appears first in the charmaps
table, but the offset used needs to point into the charmap entry, past
the name/aliases at the beginning, to the byte identifying the
encoding. as a result of this error, junk was produced.
instead, call find_charmap so we don't have to hard-code a nontrivial
offset. with this change, the code has been tested and found to work
in the case of converting the affected hkscs characters to utf-8.
Will Dietz [Thu, 3 May 2018 18:44:53 +0000 (13:44 -0500)]
fix iconv conversion to UTF-32 with implicit (big) endianness
maintainer's notes:
commit
95c6044e2ae85846330814c4ac5ebf4102dbe02c split UTF-32 and
UTF-32BE but neglected to add a case for the former as a destination
encoding, resulting in it wrongly being handled by the default case.
the intent was that the value of the macro be chosen to encode "big
endian" in the low bits, so that no code would be needed, but this was
botched; instead, handle it the way UCS2 is handled.
Will Dietz [Tue, 1 May 2018 19:16:44 +0000 (14:16 -0500)]
fix iconv buffer overflow converting to legacy JIS-based encodings
maintainer's notes:
commit
a223dbd27ae36fe53f9f67f86caf685b729593fc added the reverse
conversions to JIS-based encodings, but omitted the check for remining
buffer space in the case where the next character to be written was
single-byte, allowing conversion to continue past the end of the
destination buffer.
Rich Felker [Wed, 9 May 2018 04:33:54 +0000 (00:33 -0400)]
make linking of thread-start with explicit scheduling conditional
the wrapper start function that performs scheduling operations is
unreachable if pthread_attr_setinheritsched is never called, so move
it there rather than the pthread_create source file, saving some code
size for static-linked programs.
Rich Felker [Wed, 9 May 2018 04:14:13 +0000 (00:14 -0400)]
improve design of thread-start with explicit scheduling attributes
eliminate the awkward startlock mechanism and corresponding fields of
the pthread structure that were only used at startup.
instead of having pthread_create perform the scheduling operations and
having the new thread wait for them to be completed, start the new
thread with a wrapper start function that performs its own scheduling,
sending the result code back via a futex. this way the new thread can
use storage from the calling thread's stack rather than permanent
fields in the pthread structure.
Rich Felker [Tue, 8 May 2018 02:39:07 +0000 (22:39 -0400)]
clean up and reduce size of internal pthread structure
over time the pthread structure has accumulated a lot of cruft taking
up size. this commit removes unused fields and packs booleans and
other small data more efficiently. changes which would also require
changing code are not included at this time.
non-volatile booleans are packed as unsigned char bitfield members.
the canceldisable and cancelasync fields need volatile qualification
due to how they're accessed from the cancellation signal handler and
cancellable syscalls called from signal handlers. since volatile
bitfield semantics are not clearly defined, discrete char objects are
used instead.
the pid field is completely removed; it has been unused since commit
83dc6eb087633abcf5608ad651d3b525ca2ec35e.
the tid field's type is changed to int because its use is as a value
in futexes, which are defined as plain int. it has no conceptual
relationship to pid_t. also, its position is not ABI.
startlock is reduced to a length-1 array. the second element was
presumably intended as a waiter count, but it was never used and made
no sense, since there is at most one waiter.
Rich Felker [Sun, 6 May 2018 01:33:58 +0000 (21:33 -0400)]
improve joinable/detached thread state handling
previously, some accesses to the detached state (from pthread_join and
pthread_getattr_np) were unsynchronized; they were harmless in
programs with well-defined behavior, but ugly. other accesses (in
pthread_exit and pthread_detach) were synchronized by a poorly named
"exitlock", with an ad-hoc trylock operation on it open-coded in
pthread_detach, whose only purpose was establishing protocol for which
thread is responsible for deallocation of detached-thread resources.
instead, use an atomic detach_state and unify it with the futex used
to wait for thread exit. this eliminates 2 members from the pthread
structure, gets rid of the hackish lock usage, and makes rigorous the
trap added in commit
80bf5952551c002cf12d96deb145629765272db0 for
catching attempts to join detached threads. it should also make
attempt to detach an already-detached thread reliably trap.
Rich Felker [Fri, 4 May 2018 18:26:31 +0000 (14:26 -0400)]
improve pthread_exit synchronization with functions targeting tid
if the last thread exited via pthread_exit, the logic that marked it
dead did not account for the possibility of it targeting itself via
atexit handlers. for example, an atexit handler calling
pthread_kill(pthread_self(), SIGKILL) would return success
(previously, ESRCH) rather than causing termination via the signal.
move the release of killlock after the determination is made whether
the exiting thread is the last thread. in the case where it's not,
move the release all the way to the end of the function. this way we
can clear the tid rather than spending storage on a dedicated
dead-flag. clearing the tid is also preferable in that it hardens
against inadvertent use of the value after the thread has terminated
but before it is joined.
Rich Felker [Fri, 4 May 2018 17:18:51 +0000 (13:18 -0400)]
remove incorrect ESRCH error from pthread_kill
posix documents in the rationale and future directions for
pthread_kill that, since the lifetime of the thread id for a joinable
thread lasts until it is joined, ESRCH is not a correct error for
pthread_kill to produce when the target thread has exited but not yet
been joined, and that conforming applications cannot attempt to detect
this state. future versions of the standard may explicitly require
that ESRCH not be returned for this case.
Rich Felker [Wed, 2 May 2018 16:13:43 +0000 (12:13 -0400)]
use a dedicated futex object for pthread_join instead of tid field
the tid field in the pthread structure is not volatile, and really
shouldn't be, so as not to limit the compiler's ability to reorder,
merge, or split loads in code paths that may be relevant to
performance (like controlling lock ownership).
however, use of objects which are not volatile or atomic with futex
wait is inherently broken, since the compiler is free to transform a
single load into multiple loads, thereby using a different value for
the controlling expression of the loop and the value passed to the
futex syscall, leading the syscall to block instead of returning.
reportedly glibc's pthread_join was actually affected by an equivalent
issue in glibc on s390.
add a separate, dedicated join_futex object for pthread_join to use.
Rich Felker [Tue, 1 May 2018 20:56:02 +0000 (16:56 -0400)]
optimize sigisemptyset
the static const zero set ended up getting put in bss instead of
rodata, wasting writable memory, and the call to memcmp was
size-inefficient. generally for nonstandard extension functions we try
to avoid poking at any internals directly, but the way the zero set
was setup was arguably already doing so.
Rich Felker [Tue, 1 May 2018 18:46:59 +0000 (14:46 -0400)]
avoid excessive stack usage in getcwd
to support the GNU extension of allocating a buffer for getcwd's
result when a null pointer is passed without incurring a link
dependency on free, we use a PATH_MAX-sized buffer on the stack and
only duplicate it to allocated storage after the operation succeeds.
unfortunately this imposed excessive stack usage on all callers,
including those not making use of the GNU extension.
instead, use a VLA to make stack allocation conditional.
Rich Felker [Tue, 1 May 2018 18:34:22 +0000 (14:34 -0400)]
work around arm gcc's rejection of r7 asm constraints in thumb mode
in thumb mode, r7 is the ABI frame pointer register, and unless frame
pointer is disabled, gcc insists on treating it as a fixed register,
refusing to spill it to satisfy constraints. unfortunately, r7 is also
used in the syscall ABI for passing the syscall number.
up til now we just treated this as a requirement to disable frame
pointer when generating code as thumb, but it turns out gcc forcibly
enables frame pointer, and the fixed register constraint that goes
with it, for functions which contain VLAs. this produces an
unacceptable arch-specific constraint that (non-arm-specific) source
files making syscalls cannot use VLAs.
as a workaround, avoid r7 register constraints when producing thumb
code and instead save/restore r7 in a temp register as part of the asm
block. at some point we may want/need to support armv6-m/thumb1, so
the asm has been tweaked to be thumb1-compatible while also
near-optimal for thumb2: it allows the temp and/or syscall number to
be in high registers (necessary since r0-r5 may all be used for
syscalll args) and in thumb2 mode allows the syscall number to be an
8-bit immediate.
Rich Felker [Fri, 27 Apr 2018 15:22:39 +0000 (11:22 -0400)]
getopt_long_only: don't prefix-match long-options that match short ones
for getopt_long, partial (prefix) matches of long options always begin
with "--" and thus can never be ambiguous with a short option. for
getopt_long_only, though, a single-character option can match both a
short option and as a prefix for a long option. in this case, we
wrongly interpreted it as a prefix for the long option.
introduce a new pass, only in long-only mode, to check the prefix
match against short options before accepting it. the only reason
there's a slightly nontrivial loop being introduced rather than strchr
is that our getopt already supports multibyte short options, and
getopt_long_long should handle them consistently. a temp buffer and
strstr could have been used, but the code to set it up would be just
as large as what's introduced here and it would unnecessarily pull in
relatively large code for strstr.
Rich Felker [Fri, 20 Apr 2018 02:19:29 +0000 (22:19 -0400)]
reintroduce hardening against partially-replaced allocator
commit
618b18c78e33acfe54a4434e91aa57b8e171df89 removed the previous
detection and hardening since it was incorrect. commit
72141795d4edd17f88da192447395a48444afa10 already handled all that
remained for hardening the static-linked case. in the dynamic-linked
case, have the dynamic linker check whether malloc was replaced and
make that information available.
with these changes, the properties documented in commit
c9f415d7ea2dace5bf77f6518b6afc36bb7a5732 are restored: if calloc is
not provided, it will behave as malloc+memset, and any of the
memalign-family functions not provided will fail with ENOMEM.
Rich Felker [Fri, 20 Apr 2018 00:56:26 +0000 (20:56 -0400)]
return chunks split off by memalign using __bin_chunk instead of free
this change serves multiple purposes:
1. it ensures that static linking of memalign-family functions will
pull in the system malloc implementation, thereby causing link errors
if an attempt is made to link the system memalign functions with a
replacement malloc (incomplete allocator replacement).
2. it eliminates calls to free that are unpaired with allocations,
which are confusing when setting breakpoints or tracing execution.
as a bonus, making __bin_chunk external may discourage aggressive and
unnecessary inlining of it.
Rich Felker [Fri, 20 Apr 2018 00:45:48 +0000 (20:45 -0400)]
using malloc implementation types/macros/idioms for memalign
the generated code should be mostly unchanged, except for explicit use
of C_INUSE in place of copying the low bits from existing chunk
headers/footers.
these changes also remove mild UB due to dubious arithmetic on
pointers into imaginary size_t[] arrays.
Rich Felker [Thu, 19 Apr 2018 22:43:05 +0000 (18:43 -0400)]
move malloc implementation types and macros to an internal header
Rich Felker [Thu, 19 Apr 2018 19:25:48 +0000 (15:25 -0400)]
revert detection of partially-replaced allocator
commit
c9f415d7ea2dace5bf77f6518b6afc36bb7a5732 included checks to
make calloc fallback to memset if used with a replaced malloc that
didn't also replace calloc, and the memalign family fail if free has
been replaced. however, the checks gave false positives for
replacement whenever malloc or free resolved to a PLT entry in the
main program.
for now, disable the checks so as not to leave libc in a broken state.
this means that the properties documented in the above commit are no
longer satisfied; failure to replace calloc and the memalign family
along with malloc is unsafe if they are ever called.
the calloc checks were correct but useless for static linking. in both
cases (simple or full malloc), calloc and malloc are in a source file
together, so replacement of one but not the other would give linking
errors. the memalign-family check was useful for static linking, but
broken for dynamic as described above, and can be replaced with a
better link-time check.
Will Dietz [Wed, 18 Apr 2018 21:17:44 +0000 (16:17 -0500)]
setvbuf: minor comment typo fix
Andre McCurdy [Thu, 19 Apr 2018 01:51:44 +0000 (18:51 -0700)]
arm: use a_ll/a_sc atomics when building for ARMv6T2
ARMv6 cores with support for Thumb2 can take advantage of the "ldrex"
and "strex" based implementations of a_ll and a_sc.
Andre McCurdy [Thu, 19 Apr 2018 01:51:43 +0000 (18:51 -0700)]
arm: respect both __ARM_ARCH_6KZ__ and __ARM_ARCH_6ZK__ macros
__ARM_ARCH_6ZK__ is a gcc specific historical typo which may not be
defined by other compilers.
https://gcc.gnu.org/ml/gcc-patches/2015-07/msg02237.html
To avoid unexpected results when building for ARMv6KZ with clang, the
correct form of the macro (ie 6KZ) needs to be tested. The incorrect
form of the macro (ie 6ZK) still needs to be tested for compatibility
with pre-2015 versions of gcc.
Andre McCurdy [Thu, 19 Apr 2018 00:41:00 +0000 (17:41 -0700)]
provide optimized a_ctz_32 for arm
Provide an ARM specific a_ctz_32 helper function for architecture
versions for which it can be implemented efficiently via the "rbit"
instruction (ie all Thumb-2 capable versions of ARM v6 and above).
Andre McCurdy [Thu, 19 Apr 2018 00:40:59 +0000 (17:40 -0700)]
remove a_ctz_l from arch specific atomic_arch.h
Update atomic.h to provide a_ctz_l in all cases (atomic_arch.h should
now only provide a_ctz_32 and/or a_ctz_64).
The generic version of a_ctz_32 now takes advantage of a_clz_32 if
available and the generic a_ctz_64 now makes use of a_ctz_32.
Marc André Tanner [Sun, 11 Mar 2018 08:55:06 +0000 (09:55 +0100)]
fix out of bounds write for zero length buffer in gethostname
Rich Felker [Wed, 18 Apr 2018 19:29:18 +0000 (15:29 -0400)]
add support for caller-provided buffers to setvbuf
Rich Felker [Wed, 18 Apr 2018 19:08:16 +0000 (15:08 -0400)]
clean up allocation/setup logic for open_[w]memstream
bring these functions up to date with the current idioms we use/prefer
in fmemopen and fopencookie.
Rich Felker [Wed, 18 Apr 2018 18:57:10 +0000 (14:57 -0400)]
clean up allocation/setup logic for fmemopen
rather than manually performing pointer arithmetic to carve multiple
objects out of one allocation, use a containing struct that
encompasses them all.
Rich Felker [Wed, 18 Apr 2018 18:46:05 +0000 (14:46 -0400)]
minor cleanup in fopencookie
assign entire struct rather than member-at-a-time. don't repeat buffer
sizes; always use sizeof to ensure consistency.
Rich Felker [Tue, 17 Apr 2018 22:36:19 +0000 (18:36 -0400)]
allow interposition/replacement of allocator (malloc)
replacement is subject to conditions on the replacement functions.
they may only call functions which are async-signal-safe, as specified
either by POSIX or as an implementation-defined extension. if any
allocator functions are replaced, at least malloc, realloc, and free
must be provided. if calloc is not provided, it will behave as
malloc+memset. any of the memalign-family functions not provided will
fail with ENOMEM.
in order to implement the above properties, calloc and __memalign
check that they are using their own malloc or free, respectively.
choice to check malloc or free is based on considerations of
supporting __simple_malloc. in order to make this work, calloc is
split into separate versions for __simple_malloc and full malloc;
commit
ba819787ee93ceae94efd274f7849e317c1bff58 already did most of
the split anyway, and completing it saves an extra call frame.
previously, use of -Bsymbolic-functions made dynamic interposition
impossible. now, we are using an explicit dynamic-list, so add
allocator functions to the list. most are not referenced anyway, but
all are added for completeness.
Rich Felker [Wed, 18 Apr 2018 04:16:12 +0000 (00:16 -0400)]
refactor flockfile not to duplicate lock mechanism logic
Rich Felker [Wed, 18 Apr 2018 03:59:41 +0000 (23:59 -0400)]
fix stdio lock dependency on read-after-free not faulting
instead of using a waiters count, add a bit to the lock field
indicating that the lock may have waiters. threads which obtain the
lock after contending for it will perform a potentially-spurious wake
when they release the lock.
Rich Felker [Tue, 17 Apr 2018 20:37:30 +0000 (16:37 -0400)]
remove unused __brk function/source file
commit
e3bc22f1eff87b8f029a6ab31f1a269d69e4b053 removed all references
to __brk.
Rich Felker [Tue, 17 Apr 2018 19:55:18 +0000 (15:55 -0400)]
enable reclaim_gaps for fdpic
the existing laddr function for fdpic cannot translate ELF virtual
addresses outside of the LOAD segments to runtime addresses because
the fdpic loadmap only covers the logically-mapped part. however the
whole point of reclaim_gaps is to recover the slack space up to the
page boundaries, so it needs to work with such addresses.
add a new laddr_pg function that accepts any address in the page range
for the LOAD segment by expanding the loadmap records out to page
boundaries. only use the new version for reclaim_gaps, so as not to
impact performance of other address lookups.
also, only use laddr_pg for the start address of a gap; the end
address lies one byte beyond the end, potentially in a different page
where it would get mapped differently. instead of mapping end, apply
the length (end-start) to the mapped value of start.
Rich Felker [Tue, 17 Apr 2018 19:18:49 +0000 (15:18 -0400)]
comment __malloc_donate overflow logic
Alexander Monakov [Mon, 16 Apr 2018 17:54:36 +0000 (20:54 +0300)]
ldso, malloc: implement reclaim_gaps via __malloc_donate
Split 'free' into unmap_chunk and bin_chunk, use the latter to introduce
__malloc_donate and use it in reclaim_gaps instead of calling 'free'.
Alexander Monakov [Mon, 16 Apr 2018 17:54:35 +0000 (20:54 +0300)]
malloc: fix an over-allocation bug
Fix an instance where realloc code would overallocate by OVERHEAD bytes
amount. Manually arrange for reuse of memcpy-free-return exit sequence.
Rich Felker [Tue, 17 Apr 2018 00:12:12 +0000 (20:12 -0400)]
use explicit dynamic-list rather than symbolic-functions for linking
we have always bound symbols at libc.so link time rather than runtime
to minimize startup-time relocations and overhead of calls through the
PLT, and possibly also to preclude interposition that would not work
correctly anyway if allowed. historically, binding at link-time was
also necessary for the dynamic linker to work, but the dynamic linker
bootstrap overhaul in commit
f3ddd173806fd5c60b3f034528ca24542aecc5b9
made it unnecessary.
our use of -Bsymbolic-functions, rather than -Bsymbolic, was chosen
because the latter is incompatible with public global data; it makes
it incompatible with copy relocations in the main program. however,
not all global data needs to be public. by using --dynamic-list
instead with an explicit list, we can reduce the number of symbolic
relocations left for runtime.
this change will also allow us to permit interposition of specific
functions (e.g. the allocator) if/when we want to, by adding them to
the dynamic list.
Rich Felker [Mon, 16 Apr 2018 21:35:43 +0000 (17:35 -0400)]
fix return value of nice function
the Linux SYS_nice syscall is unusable because it does not return the
newly set priority. always use SYS_setpriority. also avoid overflows
in addition of inc by handling large inc values directly without
examining the old nice value.
Alexander Monakov [Sat, 16 Dec 2017 11:27:25 +0000 (14:27 +0300)]
optimize malloc0
Implementation of __malloc0 in malloc.c takes care to preserve zero
pages by overwriting only non-zero data. However, malloc must have
already modified auxiliary heap data just before and beyond the
allocated region, so we know that edge pages need not be preserved.
For allocations smaller than one page, pass them immediately to memset.
Otherwise, use memset to handle partial pages at the head and tail of
the allocation, and scan complete pages in the interior. Optimize the
scanning loop by processing 16 bytes per iteration and handling rest of
page via memset as soon as a non-zero byte is found.
Rich Felker [Wed, 11 Apr 2018 19:05:22 +0000 (15:05 -0400)]
fix incorrect results for catan with some inputs
the catan implementation from OpenBSD includes a FIXME-annotated
"overflow" branch that produces a meaningless and incorrect
large-magnitude result. it was reachable via three paths,
corresponding to gotos removed by this commit, in order:
1. pure imaginary argument with imaginary component greater than 1 in
magnitude. this case does not seem at all exceptional and is
handled (at least with the quality currently expected from our
complex math functions) by the existing non-exceptional code path.
2. arguments on the unit circle, including the pure-real argument 1.0.
these are not exceptional except for ±i, which should produce
results with infinite imaginary component and which lead to
computation of atan2(±0,0) in the existing non-exceptional code
path. such calls to atan2() however are well-defined by POSIX.
3. the specific argument +i. this route should be unreachable due to
the above (2), but subtle rounding effects might have made it
possible in rare cases. continuing on the non-exceptional code path
in this case would lead to computing the (real) log of an infinite
argument, then producing a NAN when multiplying it by I.
for now, remove the exceptional code paths entirely. replace the
multiplication by I with construction of a complex number using the
CMPLX macro so that the NAN issue (3) prevented cannot arise.
with these changes, catan should give reasonably correct results for
real arguments, and should no longer give completely-wrong results for
pure-imaginary arguments outside the interval (-i,+i).
Rich Felker [Mon, 9 Apr 2018 16:33:17 +0000 (12:33 -0400)]
fix wrong result in casin and many related complex functions
the factor of -i noted in the comment at the top of casin.c was
omitted from the actual code, yielding a result rotated 90 degrees and
propagating into errors in other functions defined in terms of casin.
implement multiplication by -i as a rotation of the real and imaginary
parts of the result, rather than by actual multiplication, since the
latter cannot be optimized without knowledge that the operand is
finite. here, the rotation is the actual intent, anyway.
Samuel Holland [Sat, 7 Apr 2018 14:47:16 +0000 (09:47 -0500)]
implement wcsftime padding specifier extensions
Commit
8a6bd7307da3fc4d08dd6a9277b611ccb4971354 added support for
padding specifier extensions to strftime, but did not modify wcsftime.
In the process, it added a parameter to __strftime_fmt_1 in strftime.c,
but failed to update the prototype in wcsftime.c. This was found by
compiling musl with LTO:
src/time/wcsftime.c:7:13: warning: type of '__strftime_fmt_1' does \
not match original declaration [-Wlto-type-mismatch]
Fix the prototype of __strftime_fmt_1 in wcsftime.c, and generate the
'pad' argument the same way as it is done in strftime.
Rich Felker [Thu, 5 Apr 2018 15:04:21 +0000 (11:04 -0400)]
prevent bypass of guarantee that suids start with fd 0/1/2 open
it was reported by Erik Bosman that poll fails without setting revents
when the nfds argument exceeds the current value for RLIMIT_NOFILE,
causing the subsequent open calls to be bypassed. if the rlimit is
either 1 or 2, this leaves fd 0 and 1 potentially closed but openable
when the application code is reached.
based on a brief reading of the poll syscall documentation and code,
it may be possible for poll to fail under other attacker-controlled
conditions as well. if it turns out these are reasonable conditions
that may happen in the real world, we may have to go back and
implement fallbacks to probe each fd individually if poll fails, but
for now, keep things simple and treat all poll failures as fatal.
Szabolcs Nagy [Sun, 1 Apr 2018 20:02:01 +0000 (20:02 +0000)]
fix fmaf wrong result
if double precision r=x*y+z is not a half way case between two single
precision floats or it is an exact result then fmaf returns (float)r.
however the exactness check was wrong when |x*y| < |z| and could cause
incorrectly rounded result in nearest rounding mode when r is a half
way case.
fmaf(-0x1.26524ep-54, -0x1.cb7868p+11, 0x1.d10f5ep-29)
was incorrectly rounded up to 0x1.d117ap-29 instead of 0x1.d1179ep-29.
(exact result is 0x1.d1179efffffffecp-29, r is 0x1.d1179fp-29)
Rich Felker [Wed, 28 Mar 2018 19:53:45 +0000 (15:53 -0400)]
fix default feature profile in tar.h
commit
d93c0740d86aaf7043e79b942a6c0b3f576af4c8 added use of feature
test macros without including features.h, causing a definition that
should be exposed in the default profile, TSVTX, to appear only when
_XOPEN_SOURCE or higher is explicitly defined.
Rich Felker [Sun, 25 Mar 2018 02:47:36 +0000 (22:47 -0400)]
adjust makefile target-specific CFLAGS rules to be more robust & complete
previously, MEMOPS_SRCS failed to include arch-specific replacement
files for memcpy, etc., omitting CFLAGS_MEMOPS and thereby potentially
causing build failure if an arch provided C (rather than asm)
replacements for these files.
instead of trying to explicitly include all the files that might have
arch replacements, which is prone to human error, extract final names
to be used out of $(LIBC_OBJS), where the rules for arch replacements
have already been applied. do the same for NOSSP_OBJS, using CRT_OBJS
and LDSO_OBJS rather than repeating ourselves with $(wildcard...) and
explicit pathnames again.
Rich Felker [Sat, 24 Mar 2018 16:15:43 +0000 (12:15 -0400)]
fix out-of-tree build of crt files with stack protector enabled
the makefile logic for these files was wrong in the out-of-tree case,
but it likely only affected the "all" level of stack protector.
Rich Felker [Sun, 11 Mar 2018 01:45:49 +0000 (20:45 -0500)]
explicitly use signed keyword to define intNN_t and derivative types
standing alone, both the signed and int keywords identify the same
type, a (signed) int. however the C language has an exception where,
when the lone keyword int is used to declare a bitfield, it's
implementation-defined whether the bitfield is signed or unsigned. C11
footnote 125 extends this implementation-definedness to typedefs, and
DR#315 extends it to other integer types (for which support with
bitfields is implementation-defined).
while reasonable ABIs (all the ones we support) define bitfields as
signed by default, GCC and compatible compilers offer an option
-funsigned-bitfields to change the default. while any signed types
defined without explicit use of the signed keyword are affected, the
stdint.h types, especially intNN_t, have a natural use in bitfields.
ensure that bitfields defined with these types always have the correct
signedness regardless of compiler & flags used.
see also GCC PR 83294.
Rich Felker [Sat, 10 Mar 2018 23:08:02 +0000 (18:08 -0500)]
fix minor namespace issues in termios.h
the output delay features (NL*, CR*, TAB*, BS*, and VT*) are
XSI-shaded. VT* is in the V* namespace reservation but the rest need
to be suppressed in base POSIX namespace.
unfortunately this change introduces feature test macro checks into
another bits header. at some point these checks should be simplified
by having features.h handle the "FTM X implies Y" relationships.
Rich Felker [Sat, 10 Mar 2018 23:03:17 +0000 (18:03 -0500)]
remove spurious const keyword in sigqueue declaration
this must have been taken from POSIX without realizing that it was
meaningless. the resolution to Austin Group issue #844 removed it from
the standard.
Rich Felker [Sat, 10 Mar 2018 23:02:05 +0000 (18:02 -0500)]
fix minor namespace issue in unistd.h
the F_* macros associated with the lockf function are XSI-shaded (like
the lockf function itself) and should only be exposed when the
function is.
Rich Felker [Sat, 10 Mar 2018 22:57:44 +0000 (17:57 -0500)]
fix minor namespace issue in tar.h
TSVTX is XSI-shaded.