musl
11 years agodocument more changes for 0.7.7
Rich Felker [Wed, 6 Apr 2011 18:46:37 +0000 (14:46 -0400)]
document more changes for 0.7.7

11 years agofix prototype for strsep
Rich Felker [Wed, 6 Apr 2011 18:28:29 +0000 (14:28 -0400)]
fix prototype for strsep

11 years agofix completely bogus loop condition in getmntent_r
Rich Felker [Wed, 6 Apr 2011 16:35:05 +0000 (12:35 -0400)]
fix completely bogus loop condition in getmntent_r

somehow this worked on my simple fstab, but horribly broke in general,
leading to use of uninitialized offset array and crashes.

11 years agomajor semaphore improvements (performance and correctness)
Rich Felker [Wed, 6 Apr 2011 16:24:34 +0000 (12:24 -0400)]
major semaphore improvements (performance and correctness)

1. make sem_[timed]wait interruptible by signals, per POSIX
2. keep a waiter count in order to avoid unnecessary futex wake syscalls

11 years agofix signal-based timers with null sigevent argument
Rich Felker [Wed, 6 Apr 2011 13:26:41 +0000 (09:26 -0400)]
fix signal-based timers with null sigevent argument

since timer_create is no longer allocating a structure for the timer_t
and simply using the kernel timer id, it was impossible to specify the
timer_t as the argument to the signal handler. the solution is to pass
the null sigevent pointer on to the kernel, rather than filling it in
userspace, so that the kernel does the right thing. however, that
precludes the clever timerid-versus-threadid encoding we were doing.

instead, just assume timerids are below 1M and thread pointers are
above 1M. (in perspective: timerids are sequentially allocated and
seem limited to 32k, and thread pointers are at roughly 3G.)

11 years agofix incorrect (and conflicting on LP64 archs) types for sysv ipc msgq functions
Rich Felker [Wed, 6 Apr 2011 04:02:20 +0000 (00:02 -0400)]
fix incorrect (and conflicting on LP64 archs) types for sysv ipc msgq functions

11 years agofix (hopefully) statvfs breakage on x86_64 that resulted from fixing i386...
Rich Felker [Wed, 6 Apr 2011 03:58:36 +0000 (23:58 -0400)]
fix (hopefully) statvfs breakage on x86_64 that resulted from fixing i386...

11 years agodocument more changes
Rich Felker [Tue, 5 Apr 2011 22:58:47 +0000 (18:58 -0400)]
document more changes

11 years agonew framework to inhibit thread cancellation when needed
Rich Felker [Tue, 5 Apr 2011 22:00:28 +0000 (18:00 -0400)]
new framework to inhibit thread cancellation when needed

with these small changes, libc functions which need to call functions
which are cancellation points, but which themselves must not be
cancellation points, can use the CANCELPT_INHIBIT and CANCELPT_RESUME
macros to temporarily inhibit all cancellation.

11 years agoadd ip6 pktinfo stuff for x86_64
Rich Felker [Tue, 5 Apr 2011 21:27:28 +0000 (17:27 -0400)]
add ip6 pktinfo stuff for x86_64

these defs should probably all be moved out of bits and unified...

11 years agoadd sysv ipc message queues (completely untested)
Rich Felker [Tue, 5 Apr 2011 20:33:55 +0000 (16:33 -0400)]
add sysv ipc message queues (completely untested)

11 years agogetopt.h is a GNU-getopt-specific header. always expose GNU functions.
Rich Felker [Tue, 5 Apr 2011 19:45:24 +0000 (15:45 -0400)]
getopt.h is a GNU-getopt-specific header. always expose GNU functions.

11 years agoadd sysexits.h legacy header
Rich Felker [Tue, 5 Apr 2011 19:40:36 +0000 (15:40 -0400)]
add sysexits.h legacy header

11 years agoimplement the adjtime and adjtimex functions (nonstandard)
Rich Felker [Tue, 5 Apr 2011 19:38:20 +0000 (15:38 -0400)]
implement the adjtime and adjtimex functions (nonstandard)

11 years agoadd getmntent_r interface (all of mntent is nonstandard anyway)
Rich Felker [Tue, 5 Apr 2011 18:11:14 +0000 (14:11 -0400)]
add getmntent_r interface (all of mntent is nonstandard anyway)

11 years agoadd some missing ipv6 stuff
Rich Felker [Tue, 5 Apr 2011 18:05:11 +0000 (14:05 -0400)]
add some missing ipv6 stuff

11 years agoimplement if_indextoname and if_nametoindex functions
Rich Felker [Tue, 5 Apr 2011 17:20:08 +0000 (13:20 -0400)]
implement if_indextoname and if_nametoindex functions

11 years agoadd (nonstandard) cfmakeraw function
Rich Felker [Tue, 5 Apr 2011 16:35:09 +0000 (12:35 -0400)]
add (nonstandard) cfmakeraw function

11 years agoadd pivot_root syscall wrapper
Rich Felker [Tue, 5 Apr 2011 16:32:10 +0000 (12:32 -0400)]
add pivot_root syscall wrapper

11 years agoadd more legacy functions: setlinebuf and setbuffer
Rich Felker [Tue, 5 Apr 2011 16:25:31 +0000 (12:25 -0400)]
add more legacy functions: setlinebuf and setbuffer

11 years agoalternate name for syslog.h
Rich Felker [Tue, 5 Apr 2011 16:13:54 +0000 (12:13 -0400)]
alternate name for syslog.h

11 years agouncomment IP_PKTINFO
Rich Felker [Tue, 5 Apr 2011 16:07:42 +0000 (12:07 -0400)]
uncomment IP_PKTINFO

this was a hack leftover from testing before the initial
check-in to git.

11 years agosupport the nonstandard err.h interfaces
Rich Felker [Tue, 5 Apr 2011 15:16:49 +0000 (11:16 -0400)]
support the nonstandard err.h interfaces

note that unlike the originals, these do not print the program
name/argv[0] because we have not saved it anywhere. this could be
changed in __libc_start_main if desired.

11 years agorelease notes for next bugfix release
Rich Felker [Tue, 5 Apr 2011 14:28:08 +0000 (10:28 -0400)]
release notes for next bugfix release

11 years agofix misaligned read on early string termination in strchr
Rich Felker [Tue, 5 Apr 2011 13:27:41 +0000 (09:27 -0400)]
fix misaligned read on early string termination in strchr

this could actually cause rare crashes in the case where a short
string is located at the end of a page and the following page is not
readable, and in fact this was seen in gcc compiling certain files.

11 years agofix overflow in printf %N$ argument handling
Rich Felker [Tue, 5 Apr 2011 13:24:03 +0000 (09:24 -0400)]
fix overflow in printf %N$ argument handling

11 years agofix various floating point rounding and formatting errors in *printf
Rich Felker [Tue, 5 Apr 2011 13:16:40 +0000 (09:16 -0400)]
fix various floating point rounding and formatting errors in *printf

11 years agorelease notes for 0.7.6 bugfix release
Rich Felker [Mon, 4 Apr 2011 22:00:02 +0000 (18:00 -0400)]
release notes for 0.7.6 bugfix release

11 years agofix rare but nasty under-allocation bug in malloc with large requests
Rich Felker [Mon, 4 Apr 2011 21:26:41 +0000 (17:26 -0400)]
fix rare but nasty under-allocation bug in malloc with large requests

the bug appeared only with requests roughly 2*sizeof(size_t) to
4*sizeof(size_t) bytes smaller than a multiple of the page size, and
only for requests large enough to be serviced by mmap instead of the
normal heap. it was only ever observed on 64-bit machines but
presumably could also affect 32-bit (albeit with a smaller window of
opportunity).

11 years agosimplify vdprintf implementation greatly based on recent vfprintf changes
Rich Felker [Mon, 4 Apr 2011 20:30:39 +0000 (16:30 -0400)]
simplify vdprintf implementation greatly based on recent vfprintf changes

since vfprintf will provide a temporary buffer in the case where the
target FILE has a zero buffer size, don't bother setting up a real
buffer for vdprintf. this also allows us to skip the call to fflush
since we know everything will be written out before vfprintf returns.

11 years agouse a local temp buffer for unbuffered streams in vfprintf
Rich Felker [Mon, 4 Apr 2011 20:24:49 +0000 (16:24 -0400)]
use a local temp buffer for unbuffered streams in vfprintf

this change makes it so most calls to fprintf(stderr, ...) will result
in a single writev syscall, as opposed to roughly 2*N syscalls (and
possibly more) where N is the number of format specifiers. in
principle we could use a much larger buffer, but it's best not to
increase the stack requirements too much. most messages are under 80
chars.

11 years agofix nl_langinfo to actually use the existing, correct internal version
Rich Felker [Sun, 3 Apr 2011 23:51:14 +0000 (19:51 -0400)]
fix nl_langinfo to actually use the existing, correct internal version

11 years agomake ualarm actually work (obsolete function removed from SUS)
Rich Felker [Sun, 3 Apr 2011 23:18:43 +0000 (19:18 -0400)]
make ualarm actually work (obsolete function removed from SUS)

11 years agofix various bugs in strtold:
Rich Felker [Sun, 3 Apr 2011 22:44:37 +0000 (18:44 -0400)]
fix various bugs in strtold:

0e10000000000000000000000000000000 was setting ERANGE

exponent char e/p was considered part of the match even if not
followed by a valid decimal value

"1e +10" was parsed as "1e+10"

hex digits were misinterpreted as 0..5 instead of 10..15

11 years agofix serious bug in strchr - char signedness
Rich Felker [Sun, 3 Apr 2011 22:16:11 +0000 (18:16 -0400)]
fix serious bug in strchr - char signedness

search for bytes with high bit set was giving (potentially dangerous)
wrong results. i've tested, cleaned up, and hopefully sped up this
function now.

11 years agoprototype getdtablesize (nonstandard function)
Rich Felker [Sun, 3 Apr 2011 22:15:36 +0000 (18:15 -0400)]
prototype getdtablesize (nonstandard function)

11 years agoadd setresuid/setresgid functions (nonstandard)
Rich Felker [Sun, 3 Apr 2011 20:20:57 +0000 (16:20 -0400)]
add setresuid/setresgid functions (nonstandard)

11 years agopthread_create need not set errno
Rich Felker [Sun, 3 Apr 2011 20:15:15 +0000 (16:15 -0400)]
pthread_create need not set errno

11 years agofix statvfs syscalls (missing size argument)
Rich Felker [Sun, 3 Apr 2011 19:42:31 +0000 (15:42 -0400)]
fix statvfs syscalls (missing size argument)

11 years agoblock all signals during rsyscall
Rich Felker [Sun, 3 Apr 2011 17:15:42 +0000 (13:15 -0400)]
block all signals during rsyscall

otherwise a signal handler could see an inconsistent and nonconformant
program state where different threads have different uids/gids.

11 years agofix race condition in rsyscall handler
Rich Felker [Sun, 3 Apr 2011 17:03:18 +0000 (13:03 -0400)]
fix race condition in rsyscall handler

the problem: there is a (single-instruction) race condition window
between a thread flagging itself dead and decrementing itself from the
thread count. if it receives the rsyscall signal at this exact moment,
the rsyscall caller will never succeed in signalling enough flags to
succeed, and will deadlock forever. in previous versions of musl, the
about-to-terminate thread masked all signals prior to decrementing
the thread count, but this cost a whole syscall just to account for
extremely rare races.

the solution is a huge hack: rather than blocking in the signal
handler if the thread is dead, modify the signal mask of the saved
context and return in order to prevent further signal handling by the
dead thread. this allows the dead thread to continue decrementing the
thread count (if it had not yet done so) and exiting, even while the
live part of the program blocks for rsyscall.

11 years agodon't trust siginfo in rsyscall handler
Rich Felker [Sun, 3 Apr 2011 16:20:51 +0000 (12:20 -0400)]
don't trust siginfo in rsyscall handler

for some inexplicable reason, linux allows the sender of realtime
signals to spoof its identity. permission checks for sending signals
should limit the impact to same-user processes, but just to be safe,
we avoid trusting the siginfo structure and instead simply examine the
program state to see if we're in the middle of a legitimate rsyscall.

11 years agotimer threads should sleep and stay asleep... a long time
Rich Felker [Sun, 3 Apr 2011 16:10:24 +0000 (12:10 -0400)]
timer threads should sleep and stay asleep... a long time

11 years agorevert to deleting kernel-level timer from cancellation handler
Rich Felker [Sun, 3 Apr 2011 16:08:34 +0000 (12:08 -0400)]
revert to deleting kernel-level timer from cancellation handler

this is necessary in order to avoid breaking timer_getoverrun in the
last run of the timer event handler, if it has not yet finished.

11 years agosimplify calling of timer signal handler
Rich Felker [Sun, 3 Apr 2011 16:03:58 +0000 (12:03 -0400)]
simplify calling of timer signal handler

11 years agod_fileno alias for d_ino in dirent
Rich Felker [Sun, 3 Apr 2011 14:24:59 +0000 (10:24 -0400)]
d_fileno alias for d_ino in dirent

this is nonstandard but since POSIX reserved d_ prefix in dirent.h we
might as well define it unconditionally. some programs depend on it.

11 years agosimplify pthread tsd key handling
Rich Felker [Sun, 3 Apr 2011 06:40:18 +0000 (02:40 -0400)]
simplify pthread tsd key handling

11 years agoomit pthread tsd dtor code if tsd is not used
Rich Felker [Sun, 3 Apr 2011 06:33:50 +0000 (02:33 -0400)]
omit pthread tsd dtor code if tsd is not used

11 years agodon't disable seeking after first seek failure
Rich Felker [Sat, 2 Apr 2011 17:55:54 +0000 (13:55 -0400)]
don't disable seeking after first seek failure

this could cause problems if the application uses dup2(fd,fileno(f))
to redirect, and the old fd was not seekable but the new fd is.

11 years agoapparently fseek should not set the error flag on failed seek
Rich Felker [Sat, 2 Apr 2011 17:54:55 +0000 (13:54 -0400)]
apparently fseek should not set the error flag on failed seek

11 years agoupdate release notes
Rich Felker [Sat, 2 Apr 2011 03:15:29 +0000 (23:15 -0400)]
update release notes

11 years agoavoid over-allocation of brk on first malloc
Rich Felker [Sat, 2 Apr 2011 03:07:03 +0000 (23:07 -0400)]
avoid over-allocation of brk on first malloc

if init_malloc returns positive (successful first init), malloc will
retry getting a chunk from the free bins rather than expanding the
heap again. also pass init_malloc a hint for the size of the initial
allocation.

11 years agoreorganize the __libc structure for threaded performance issues
Rich Felker [Sat, 2 Apr 2011 02:35:20 +0000 (22:35 -0400)]
reorganize the __libc structure for threaded performance issues

we want to keep atomically updated fields (locks and thread count) and
really anything writable far away from frequently-needed function
pointers. stuff some rarely-needed function pointers in between to
pad, hopefully up to a cache line boundary.

11 years agosimplify setting result on thread cancellation
Rich Felker [Sat, 2 Apr 2011 02:15:03 +0000 (22:15 -0400)]
simplify setting result on thread cancellation

11 years agouse bss instead of mmap for main thread's pthread thread-specific data
Rich Felker [Sat, 2 Apr 2011 02:07:59 +0000 (22:07 -0400)]
use bss instead of mmap for main thread's pthread thread-specific data

this simplifies code and removes a failure case

11 years agoremove obsolete and useless useconds_t type
Rich Felker [Sat, 2 Apr 2011 01:10:01 +0000 (21:10 -0400)]
remove obsolete and useless useconds_t type

11 years agosomehow timespec tv_nsec had the wrong type on x86_64... fixed
Rich Felker [Sat, 2 Apr 2011 00:58:40 +0000 (20:58 -0400)]
somehow timespec tv_nsec had the wrong type on x86_64... fixed

11 years agofix misspelled PTHREAD_CANCELED constant
Rich Felker [Sat, 2 Apr 2011 00:48:02 +0000 (20:48 -0400)]
fix misspelled PTHREAD_CANCELED constant

11 years agodocument more changes
Rich Felker [Sat, 2 Apr 2011 00:47:54 +0000 (20:47 -0400)]
document more changes

11 years agodocument changes for upcoming 0.7.5 release
Rich Felker [Sat, 2 Apr 2011 00:36:01 +0000 (20:36 -0400)]
document changes for upcoming 0.7.5 release

11 years agouse a_store to set cancel flag in pthread_cancel, to ensure a barrier
Rich Felker [Fri, 1 Apr 2011 23:53:16 +0000 (19:53 -0400)]
use a_store to set cancel flag in pthread_cancel, to ensure a barrier

11 years agosimplify pthread_key_delete
Rich Felker [Thu, 31 Mar 2011 23:06:22 +0000 (19:06 -0400)]
simplify pthread_key_delete

calling this function on an uninitialized key value is UB, so there is
no need to check that the table pointer was initialized.

11 years agogreatly simplify pthread_key_create (~20% size reduction)
Rich Felker [Thu, 31 Mar 2011 23:04:56 +0000 (19:04 -0400)]
greatly simplify pthread_key_create (~20% size reduction)

11 years agoadd some missing prototypes for nonstandard functions (strsep, clearenv)
Rich Felker [Wed, 30 Mar 2011 18:14:26 +0000 (14:14 -0400)]
add some missing prototypes for nonstandard functions (strsep, clearenv)

11 years agoavoid all malloc/free in timer creation/destruction
Rich Felker [Wed, 30 Mar 2011 17:04:55 +0000 (13:04 -0400)]
avoid all malloc/free in timer creation/destruction

instead of allocating a userspace structure for signal-based timers,
simply use the kernel timer id. we use the fact that thread pointers
will always be zero in the low bit (actually more) to encode integer
timerid values as pointers.

also, this change ensures that the timer_destroy syscall has completed
before the library timer_destroy function returns, in case it matters.

11 years agooptimize timer creation and possibly protect against some minor races
Rich Felker [Wed, 30 Mar 2011 16:06:39 +0000 (12:06 -0400)]
optimize timer creation and possibly protect against some minor races

the major idea of this patch is not to depend on having the timer
pointer delivered to the signal handler, and instead use the thread
pointer to get the callback function address and argument. this way,
the parent thread can make the timer_create syscall while the child
thread is starting, and it should never have to block waiting for the
barrier.

11 years agoavoid crash on stupid but allowable usage of pthread_mutex_unlock
Rich Felker [Wed, 30 Mar 2011 14:32:45 +0000 (10:32 -0400)]
avoid crash on stupid but allowable usage of pthread_mutex_unlock

unlocking an unlocked mutex is not UB for robust or error-checking
mutexes, so we must avoid calling __pthread_self (which might crash
due to lack of thread-register initialization) until after checking
that the mutex is locked.

11 years agorename __simple_malloc.c to lite_malloc.c - yes this affects behavior!
Rich Felker [Wed, 30 Mar 2011 13:29:49 +0000 (09:29 -0400)]
rename __simple_malloc.c to lite_malloc.c - yes this affects behavior!

why does this affect behavior? well, the linker seems to traverse
archive files starting from its current position when resolving
symbols. since calloc.c comes alphabetically (and thus in sequence in
the archive file) between __simple_malloc.c and malloc.c, attempts to
resolve the "malloc" symbol for use by calloc.c were pulling in the
full malloc.c implementation rather than the __simple_malloc.c
implementation.

as of now, lite_malloc.c and malloc.c are adjacent in the archive and
in the correct order, so malloc.c should never be used to resolve
"malloc" unless it's already needed to resolve another symbol ("free"
or "realloc").

11 years agostreamline mutex unlock to remove a useless branch, use a_store to unlock
Rich Felker [Wed, 30 Mar 2011 13:06:00 +0000 (09:06 -0400)]
streamline mutex unlock to remove a useless branch, use a_store to unlock

this roughly halves the cost of pthread_mutex_unlock, at least for
non-robust, normal-type mutexes.

the a_store change is in preparation for future support of archs which
require a memory barrier or special atomic store operation, and also
should prevent the possibility of the compiler misordering writes.

11 years agocheap special-case optimization for normal mutexes
Rich Felker [Wed, 30 Mar 2011 12:58:25 +0000 (08:58 -0400)]
cheap special-case optimization for normal mutexes

cycle-level benchmark on atom cpu showed typical pthread_mutex_lock
call dropping from ~120 cycles to ~90 cycles with this change. benefit
may vary with compiler options and version, but this optimization is
very cheap to make and should always help some.

11 years agoreorder timer initialization so that timer_create does not depend on free
Rich Felker [Wed, 30 Mar 2011 02:43:13 +0000 (22:43 -0400)]
reorder timer initialization so that timer_create does not depend on free

this allows small programs which only create times, but never delete
them, to use simple_malloc instead of the full malloc.

11 years agomissing prototype for wcscoll (stub)
Rich Felker [Tue, 29 Mar 2011 22:30:27 +0000 (18:30 -0400)]
missing prototype for wcscoll (stub)

11 years agorevert mutex "optimization" that turned out to be worse
Rich Felker [Tue, 29 Mar 2011 19:11:25 +0000 (15:11 -0400)]
revert mutex "optimization" that turned out to be worse

11 years agoimplement POSIX timers
Rich Felker [Tue, 29 Mar 2011 17:01:25 +0000 (13:01 -0400)]
implement POSIX timers

this implementation is superior to the glibc/nptl implementation, in
that it gives true realtime behavior. there is no risk of timer
expiration events being lost due to failed thread creation or failed
malloc, because the thread is created as time creation time, and
reused until the timer is deleted.

11 years agomajor improvements to cancellation handling
Rich Felker [Tue, 29 Mar 2011 16:58:22 +0000 (12:58 -0400)]
major improvements to cancellation handling

- there is no longer any risk of spoofing cancellation requests, since
  the cancel flag is set in pthread_cancel rather than in the signal
  handler.

- cancellation signal is no longer unblocked when running the
  cancellation handlers. instead, pthread_create will cause any new
  threads created from a cancellation handler to unblock their own
  cancellation signal.

- various tweaks in preparation for POSIX timer support.

11 years agosome preliminaries for adding POSIX timers
Rich Felker [Tue, 29 Mar 2011 14:05:57 +0000 (10:05 -0400)]
some preliminaries for adding POSIX timers

11 years agofix tempnam name generation, and a small bug in tmpnam on retry limit
Rich Felker [Tue, 29 Mar 2011 13:00:22 +0000 (09:00 -0400)]
fix tempnam name generation, and a small bug in tmpnam on retry limit

11 years agomake tmpfile fail after exceeding max tries.
Rich Felker [Tue, 29 Mar 2011 12:37:57 +0000 (08:37 -0400)]
make tmpfile fail after exceeding max tries.

11 years agofix tmpnam to generate better names, not depend on non-ISO-C symbols
Rich Felker [Tue, 29 Mar 2011 12:34:47 +0000 (08:34 -0400)]
fix tmpnam to generate better names, not depend on non-ISO-C symbols

11 years agofix messed-up errno if remove fails for a non-EISDIR reason
Rich Felker [Tue, 29 Mar 2011 12:25:59 +0000 (08:25 -0400)]
fix messed-up errno if remove fails for a non-EISDIR reason

11 years agolearned something new - remove is supposed to support directories on POSIX
Rich Felker [Tue, 29 Mar 2011 12:24:28 +0000 (08:24 -0400)]
learned something new - remove is supposed to support directories on POSIX

11 years agorevert some more spin optimizations that turned out to be pessimizations
Rich Felker [Tue, 29 Mar 2011 02:36:55 +0000 (22:36 -0400)]
revert some more spin optimizations that turned out to be pessimizations

11 years agofix bug from syscall overhaul: extra __syscall_ret call for 0-arg syscalls
Rich Felker [Tue, 29 Mar 2011 02:34:27 +0000 (22:34 -0400)]
fix bug from syscall overhaul: extra __syscall_ret call for 0-arg syscalls

this mainly just caused bloat, but could corrupt errno if a 0-arg
syscall ever failed.

11 years agofix broken spinlock due to miscompilation
Rich Felker [Tue, 29 Mar 2011 02:22:54 +0000 (22:22 -0400)]
fix broken spinlock due to miscompilation

actually this trick also seems to have made the uncontended case slower.

11 years agoprototype for getpass
Rich Felker [Tue, 29 Mar 2011 00:43:51 +0000 (20:43 -0400)]
prototype for getpass

11 years agoremove useless field in pthread struct (wasted a good bit of space)
Rich Felker [Tue, 29 Mar 2011 00:29:08 +0000 (20:29 -0400)]
remove useless field in pthread struct (wasted a good bit of space)

11 years agofix getc - the classic error of trying to store EOF+0-255 in a char type..
Rich Felker [Mon, 28 Mar 2011 21:31:01 +0000 (17:31 -0400)]
fix getc - the classic error of trying to store EOF+0-255 in a char type..

11 years agomajor stdio overhaul, using readv/writev, plus other changes
Rich Felker [Mon, 28 Mar 2011 05:14:44 +0000 (01:14 -0400)]
major stdio overhaul, using readv/writev, plus other changes

the biggest change in this commit is that stdio now uses readv to fill
the caller's buffer and the FILE buffer with a single syscall, and
likewise writev to flush the FILE buffer and write out the caller's
buffer in a single syscall.

making this change required fundamental architectural changes to
stdio, so i also made a number of other improvements in the process:

- the implementation no longer assumes that further io will fail
  following errors, and no longer blocks io when the error flag is set
  (though the latter could easily be changed back if desired)

- unbuffered mode is no longer implemented as a one-byte buffer. as a
  consequence, scanf unreading has to use ungetc, to the unget buffer
  has been enlarged to hold at least 2 wide characters.

- the FILE structure has been rearranged to maintain the locations of
  the fields that might be used in glibc getc/putc type macros, while
  shrinking the structure to save some space.

- error cases for fflush, fseek, etc. should be more correct.

- library-internal macros are used for getc_unlocked and putc_unlocked
  now, eliminating some ugly code duplication. __uflow and __overflow
  are no longer used anywhere but these macros. switch to read or
  write mode is also separated so the code can be better shared, e.g.
  with ungetc.

- lots of other small things.

11 years agomatch glibc/lsb cancellation abi on i386
Rich Felker [Sat, 26 Mar 2011 02:13:57 +0000 (22:13 -0400)]
match glibc/lsb cancellation abi on i386

glibc made the ridiculous choice to use pass-by-register calling
convention for these functions, which is impossible to duplicate
directly on non-gcc compilers. instead, we use ugly asm to wrap and
convert the calling convention. presumably this works with every
compiler anyone could potentially want to use.

11 years agoremove -Wno-pointer-sign example from dist/config.mak
Rich Felker [Fri, 25 Mar 2011 20:50:49 +0000 (16:50 -0400)]
remove -Wno-pointer-sign example from dist/config.mak

11 years agofix all implicit conversion between signed/unsigned pointers
Rich Felker [Fri, 25 Mar 2011 20:34:03 +0000 (16:34 -0400)]
fix all implicit conversion between signed/unsigned pointers

sadly the C language does not specify any such implicit conversion, so
this is not a matter of just fixing warnings (as gcc treats it) but
actual errors. i would like to revisit a number of these changes and
possibly revise the types used to reduce the number of casts required.

11 years agosimplify and optimize FILE lock handling
Rich Felker [Fri, 25 Mar 2011 03:16:52 +0000 (23:16 -0400)]
simplify and optimize FILE lock handling

11 years agoprepare pthread_spin_unlock for archs that need memory barriers
Rich Felker [Fri, 25 Mar 2011 03:06:48 +0000 (23:06 -0400)]
prepare pthread_spin_unlock for archs that need memory barriers

11 years agooptimize contended case for pthread_spin_trylock
Rich Felker [Fri, 25 Mar 2011 03:06:08 +0000 (23:06 -0400)]
optimize contended case for pthread_spin_trylock

11 years agooptimize spinlock spin
Rich Felker [Fri, 25 Mar 2011 03:05:17 +0000 (23:05 -0400)]
optimize spinlock spin

11 years agofix non-atomicity of puts
Rich Felker [Fri, 25 Mar 2011 02:58:21 +0000 (22:58 -0400)]
fix non-atomicity of puts

11 years agooverhaul cancellation to fix resource leaks and dangerous behavior with signals
Rich Felker [Thu, 24 Mar 2011 18:18:00 +0000 (14:18 -0400)]
overhaul cancellation to fix resource leaks and dangerous behavior with signals

this commit addresses two issues:

1. a race condition, whereby a cancellation request occurring after a
syscall returned from kernelspace but before the subsequent
CANCELPT_END would cause cancellable resource-allocating syscalls
(like open) to leak resources.

2. signal handlers invoked while the thread was blocked at a
cancellation point behaved as if asynchronous cancellation mode wer in
effect, resulting in potentially dangerous state corruption if a
cancellation request occurs.

the glibc/nptl implementation of threads shares both of these issues.

with this commit, both are fixed. however, cancellation points
encountered in a signal handler will not be acted upon if the signal
was received while the thread was already at a cancellation point.
they will of course be acted upon after the signal handler returns, so
in real-world usage where signal handlers quickly return, it should
not be a problem. it's possible to solve this problem too by having
sigaction() wrap all signal handlers with a function that uses a
pthread_cleanup handler to catch cancellation, patch up the saved
context, and return into the cancellable function that will catch and
act upon the cancellation. however that would be a lot of complexity
for minimal if any benefit...

11 years agovery cheap double-free checks in malloc
Rich Felker [Wed, 23 Mar 2011 17:24:00 +0000 (13:24 -0400)]
very cheap double-free checks in malloc

11 years agoglobal cleanup to use the new syscall interface
Rich Felker [Sun, 20 Mar 2011 04:16:43 +0000 (00:16 -0400)]
global cleanup to use the new syscall interface

11 years agoif returning errno value directly from a syscall, we need to negate it.
Rich Felker [Sun, 20 Mar 2011 03:18:34 +0000 (23:18 -0400)]
if returning errno value directly from a syscall, we need to negate it.