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2012-02-02make stdio open, read, and write operations cancellation pointsRich Felker3-5/+28
it should be noted that only the actual underlying buffer flush and fill operations are cancellable, not reads from or writes to the buffer. this behavior is compatible with POSIX, which makes all cancellation points in stdio optional, and it achieves the goal of allowing cancellation of a thread that's "stuck" on IO (due to a non-responsive socket/pipe peer, slow/stuck hardware, etc.) without imposing any measurable performance cost.
2011-10-14simplify atexit and fflush-on-exit handlingRich Felker1-1/+4
2011-09-28don't crash on null strings in printfRich Felker1-1/+1
passing null pointer for %s is UB but lots of broken programs do it anyway
2011-09-21avoid setting FILE lock count when not using flockfileRich Felker1-1/+1
for now this is just a tiny optimization, but later if we support cancellation from __stdio_read and __stdio_write, it will be necessary for the recusrive lock count to be zero in order for these functions to know they are responsible for unlocking the FILE on cancellation.
2011-09-04more fmemopen null termination fixesRich Felker1-2/+3
null termination is only added when current size grows. in update modes, null termination is not added if it does not fit (i.e. it is not allowed to clobber data). these rules make very little sense, but that's how it goes..
2011-09-04fix some fmemopen behaviorsRich Felker1-4/+7
read should not be allowed past "current size". append mode should write at "current size", not buffer size. null termination should not be written except when "current size" grows.
2011-09-04fmemopen: fix eof handling, hopefully right this timeRich Felker1-3/+4
2011-09-04fmemopen fixesRich Felker1-1/+3
disallow seek past end of buffer (per posix) fix position accounting to include data buffered for read don't set eof flag when no data was requested
2011-09-04memstreams: fix incorrect handling of file pos > current sizeRich Felker2-4/+4
the addition is safe and cannot overflow because both operands are positive when considered as signed quantities.
2011-09-04optimize seek function for memory streamsRich Felker2-24/+6
2011-09-04fix twos complement overflow bug in mem streams boundary checkRich Felker2-2/+2
the expression -off is not safe in case off is the most-negative value. instead apply - to base which is known to be non-negative and bounded within sanity.
2011-09-03implement fmemopenRich Felker1-18/+66
testing so far has been minimal. may need further work.
2011-09-03fix some length calculations in memory streamsRich Felker2-3/+3
2011-09-03implement open_wmemstreamRich Felker1-0/+95
not heavily tested, but it seems to be correct, including the odd behavior that seeking is in terms of wide character count. this precludes any simple buffering, so we just make the stream unbuffered.
2011-09-03implement open_memstreamRich Felker1-0/+94
this is the first attempt, and may have bugs. only minimal testing has been performed.
2011-08-01fix crash in dns code with new stdio locking codeRich Felker1-0/+1
2011-07-30add proper fuxed-based locking for stdioRich Felker14-39/+44
previously, stdio used spinlocks, which would be unacceptable if we ever add support for thread priorities, and which yielded pathologically bad performance if an application attempted to use flockfile on a key file as a major/primary locking mechanism. i had held off on making this change for fear that it would hurt performance in the non-threaded case, but actually support for recursive locking had already inflicted that cost. by having the internal locking functions store a flag indicating whether they need to perform unlocking, rather than using the actual recursive lock counter, i was able to combine the conditionals at unlock time, eliminating any additional cost, and also avoid a nasty corner case where a huge number of calls to ftrylockfile could cause deadlock later at the point of internal locking. this commit also fixes some issues with usage of pthread_self conflicting with __attribute__((const)) which resulted in crashes with some compiler versions/optimizations, mainly in flockfile prior to pthread_create.
2011-07-30eliminate dependence of perror on printfRich Felker1-10/+5
2011-07-16fix logic error in freadRich Felker1-6/+1
fread was calling f->read without checking that the file was in reading mode. this could: 1. crash, if f->read was a null pointer 2. cause unwanted blocking on a terminal already at eof 3. allow reading on a write-only file
2011-07-04printf: "if a precision is specified, the '0' flag shall be ignored."Rich Felker1-1/+1
2011-07-04zero precision with zero value should not inhibit prefix/width printingRich Felker1-1/+4
2011-07-04printf("%#x",0) should print 0 not 0x0Rich Felker1-1/+1
2011-06-30fix logic in __fwritingRich Felker1-1/+1
2011-06-30add and consolidate nasty stdio_ext junkRich Felker3-17/+57
hopefully this resolves the rest of the issues with hideously nonportable hacks in programs that use gnulib.
2011-06-30implement the nonstandard GNU function fpurgeRich Felker1-0/+11
this is a really ugly and backwards function, but its presence will prevent lots of broken gnulib software from trying to define its own version of fpurge and thereby failing to build or worse.
2011-06-13avoid 64bit warnings when using pointers as entropy for temp namesRich Felker2-2/+4
2011-05-11fix the last known rounding bug in floating point printingRich Felker1-3/+4
the observed symptom was that the code was incorrectly rounding up 1.0625 to 1.063 despite the rounding mode being round-to-nearest with ties broken by rounding to even last place. however, the code was just not right in many respects, and i'm surprised it worked as well as it did. this time i tested the values that end up in the variables round, small, and the expression round+small, and all look good.
2011-05-06reduce some ridiculously large spin countsRich Felker1-1/+1
these should be tweaked according to testing. offhand i know 1000 is too low and 5000 is likely to be sufficiently high. consider trying to add futexes to file locking, too...
2011-05-02fix fclose return status logic, againRich Felker1-1/+2
the previous fix was incorrect, as it would prevent f->close(f) from being called if fflush(f) failed. i believe this was the original motivation for using | rather than ||. so now let's just use a second statement to constrain the order of function calls, and to back to using |.
2011-05-01fix undefined call order in fclose, possible lost output depending on compilerRich Felker1-1/+1
pcc turned up this bug by calling f->close(f) before fflush(f), resulting in lost output and error on flush.
2011-05-01minor optimization in puts: use inline putc_unlocked macro for newlineRich Felker1-1/+1
2011-04-25fix 2 eof-related bugs in scanfRich Felker1-3/+4
1. failed match of literal chars from the format string would always return matching failure rather than input failure at eof, leading to infinite loops in some programs. 2. unread of eof would wrongly adjust the character counts reported by %n, yielding an off-by-one error.
2011-04-17clean up handling of thread/nothread mode, lockingRich Felker2-5/+1
2011-04-17debloat: use __syscall instead of syscall where possibleRich Felker4-5/+5
don't waste time (and significant code size due to function call overhead!) setting errno when the result of a syscall does not matter or when it can't fail.
2011-04-15avoid setting errno when checking for ttyRich Felker2-2/+2
setting errno here is completely valid, but some programs, notably busybox printf, assume that errno will not be set during output and treat this as an error condition. in any case, skipping it slightly reduces code size and saves time.
2011-04-14make tmpfile slightly more efficient (use unlink syscall instead of remove)Rich Felker1-1/+1
2011-04-12fix printf("%.9g", 1.1) and similar not dropping trailing zerosRich Felker1-1/+3
2011-04-11fix fputwc return valueRich Felker1-1/+1
2011-04-09work around a nasty bug in linux readv syscallRich Felker1-3/+4
according to posix, readv "shall be equivalent to read(), except..." that it places the data into the buffers specified by the iov array. however on linux, when reading from a terminal, each iov element behaves almost like a separate read. this means that if the first iov exactly satisfied the request (e.g. a length-one read of '\n') and the second iov is nonzero length, the syscall will block again after getting the blank line from the terminal until another line is read. simply put, entering a single blank line becomes impossible. the solution, fortunately, is simple. whenever the buffer size is nonzero, reduce the length of the requested read by one byte and let the last byte go through the buffer. this way, readv will already be in the second (and last) iov, and won't re-block on the second iov.
2011-04-05add more legacy functions: setlinebuf and setbufferRich Felker3-1/+15
2011-04-05fix overflow in printf %N$ argument handlingRich Felker1-2/+2
2011-04-05fix various floating point rounding and formatting errors in *printfRich Felker1-17/+25
2011-04-04simplify vdprintf implementation greatly based on recent vfprintf changesRich Felker1-5/+2
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.
2011-04-04use a local temp buffer for unbuffered streams in vfprintfRich Felker2-0/+14
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.
2011-04-02don't disable seeking after first seek failureRich Felker1-8/+0
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.
2011-04-02apparently fseek should not set the error flag on failed seekRich Felker1-4/+1
2011-03-29fix tempnam name generation, and a small bug in tmpnam on retry limitRich Felker2-21/+20
2011-03-29make tmpfile fail after exceeding max tries.Rich Felker1-2/+6
2011-03-29fix tmpnam to generate better names, not depend on non-ISO-C symbolsRich Felker1-25/+17
2011-03-29fix messed-up errno if remove fails for a non-EISDIR reasonRich Felker1-2/+2