- 01 10月, 2012 1 次提交
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由 Rich Felker 提交于
1. don't make non-cloexec file descriptors 2. cancellation safety (cleanup handlers were missing, now unneeded) 3. share name validation/mapping code between open/unlink functions 4. avoid wasteful/slow syscalls
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- 30 9月, 2012 10 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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由 Rich Felker 提交于
this feature will be in the next version of POSIX, and can be used internally immediately. there are many internal uses of fopen where close-on-exec is needed to fix bugs.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
it will be in the next version of POSIX
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由 Rich Felker 提交于
they will be in the next version of POSIX
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由 Rich Felker 提交于
these interfaces have been adopted by the Austin Group for inclusion in the next version of POSIX.
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由 Rich Felker 提交于
also update syslog to use SOCK_CLOEXEC rather than separate fcntl step, to make it safe in multithreaded programs that run external programs. emulation is not atomic; it could be made atomic by holding a lock on forking during the operation, but this seems like overkill. my goal is not to achieve perfect behavior on old kernels (which have plenty of other imperfect behavior already) but to avoid catastrophic breakage in (1) syslog, which would give no output on old kernels with the change to use SOCK_CLOEXEC, and (2) programs built on a new kernel where configure scripts detected a working SOCK_CLOEXEC, which later get run on older kernels (they may otherwise fail to work completely).
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由 Rich Felker 提交于
this did not matter because we don't yet treat process-shared special. when private futex support is added, however, it will matter.
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由 Rich Felker 提交于
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- 29 9月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
based on initial work by rdp, with heavy modifications. some features including threads are untested because qemu app-level emulation seems to be broken and I do not have a proper system image for testing.
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- 28 9月, 2012 3 次提交
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由 Rich Felker 提交于
the code to exit the new thread/process after the start function returns was mixed up in its syscall convention.
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由 Rich Felker 提交于
when strchr fails, and important piece of information already computed, the string length, is thrown away. have strchrnul (with namespace protection) be the underlying function so this information can be kept, and let strchr be a wrapper for it. this also allows strcspn to be considerably faster in the case where the match set has a single element that's not matched.
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由 Rich Felker 提交于
testing with gcc 4.6.3 on x86, -Os, the old version does a duplicate null byte check after the first loop. this is purely the compiler being stupid, but the old code was also stupid and unintuitive in how it expressed the check.
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- 26 9月, 2012 1 次提交
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由 Rich Felker 提交于
also optimized a bit.
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- 25 9月, 2012 1 次提交
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由 Rich Felker 提交于
austin group interpretation for defect #529 (http://austingroupbugs.net/view.php?id=529) tightens the requirements on close such that, if it returns with EINTR, the file descriptor must not be closed. the linux kernel developers vehemently disagree with this, and will not change it. we catch and remap EINTR to EINPROGRESS, which the standard allows close() to return when the operation was not finished but the file descriptor has been closed.
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- 23 9月, 2012 2 次提交
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由 Rich Felker 提交于
new behavior can be summarized as: inputs that parse completely as a decimal number are treated as one, and rejected only if the result is out of 16-bit range. inputs that do not parse as a decimal number (where strtoul leaves anything left over in the input) are searched in /etc/services.
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由 Rich Felker 提交于
also cleanup cruft related to the issue
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- 22 9月, 2012 3 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
not tested on mips and arm; they may still be broken. x86_64 should be ok now.
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由 Rich Felker 提交于
this is useful when the underlying gcc is already a wrapper, which is the case at least on some uclibc-based system images. it's also useful for running an older/newer/nondefault version of gcc.
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- 21 9月, 2012 1 次提交
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由 Rich Felker 提交于
issue reported/requested by Justin Cormack
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- 17 9月, 2012 1 次提交
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由 Rich Felker 提交于
patch by Justin Cormack, with slight modification
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- 16 9月, 2012 4 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
the linux O_PATH mode provides the necessary semantics for both the O_SEARCH and O_EXEC modes defined and required by POSIX 2008.
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由 Rich Felker 提交于
contributed by nsz
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由 Rich Felker 提交于
this could cause major bugs, and warrants a fix release right away.
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- 15 9月, 2012 8 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
no problems were detected so far, but the constraints seem to have been invalid just like the mips ones.
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由 Rich Felker 提交于
it was determined in discussion that these kind of limits are not sufficient to protect single-threaded servers against denial of service attacks from maliciously large round counts. the time scales simply vary too much; many users will want login passwords with rounds counts on a scale that gives decisecond latency, while highly loaded webservers will need millisecond latency or shorter. still some limit is left in place; the idea is not to protect against attacks, but to avoid the runtime of a single call to crypt being, for all practical purposes, infinite, so that configuration errors can be caught and fixed without bringing down whole systems. these limits are very high, on the order of minute-long runtimes for modest systems.
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由 Rich Felker 提交于
these fixes were already made to the normal syscall asm but not the cancellation point version.
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由 Rich Felker 提交于
if same register is used for input/output, the compiler must be told. otherwise is generates random junk code that clobbers the result. in pure syscall-wrapper functions, nothing went wrong, but in more complex functions where register allocation is non-trivial, things broke badly.
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由 Rich Felker 提交于
with this patch, the malloc in libc.so built with -Os is nearly the same speed as the one built with -O3. thus it solves the performance regression that resulted from removing the forced -O3 when building libc.so; now libc.so can be both small and fast.
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由 Rich Felker 提交于
I originally added -O3 for shared libraries to counteract very bad behavior by GCC when building PIC code: it insists on reloading the GOT register in static functions that need it, even if the address of the function is never leaked from the translation unit and all local callers of the function have already loaded the GOT register. this measurably degrades performance in a few key areas like malloc. the inlining done at -O3 avoids the issue, but that's really not a good reason for overriding the user's choice of optimization level.
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由 Rich Felker 提交于
vfork is implemented as the fork syscall (with no atfork handlers run) on archs where it is not available, so this change does not introduce any change in behavior or regression for such archs.
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- 14 9月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
I'm not 100% sure that Linux's O_PATH meets the POSIX requirements for O_SEARCH, but it seems very close if not perfect. and old kernels ignore it, so O_SEARCH will still work as desired as long as the caller has read permissions to the directory.
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- 11 9月, 2012 1 次提交
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由 Rich Felker 提交于
by using the "ir" constraint (immediate or register) and the carefully constructed instruction addu $2,$0,%2 which can take either an immediate or a register for %2, the new inline asm admits maximal optimization with no register spillage to the stack when the compiler successfully performs constant propagration, but still works by allocating a register when the syscall number cannot be recognized as a constant. in the case of syscalls with 0-3 arguments it barely matters, but for 4-argument syscalls, using an immediate for the syscall number avoids creating a stack frame for the syscall wrapper function.
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