- 30 5月, 2014 1 次提交
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由 Rich Felker 提交于
such archs are expected to omit definitions of the SYS_* macros for syscalls their kernels lack from arch/$ARCH/bits/syscall.h. the preprocessor is then able to select the an appropriate implementation for affected functions. two basic strategies are used on a case-by-case basis: where the old syscalls correspond to deprecated library-level functions, the deprecated functions have been converted to wrappers for the modern function, and the modern function has fallback code (omitted at the preprocessor level on new archs) to make use of the old syscalls if the new syscall fails with ENOSYS. this also improves functionality on older kernels and eliminates the incentive to program with deprecated library-level functions for the sake of compatibility with older kernels. in other situations where the old syscalls correspond to library-level functions which are not deprecated but merely lack some new features, such as the *at functions, the old syscalls are still used on archs which support them. this may change at some point in the future if or when fallback code is added to the new functions to make them usable (possibly with reduced functionality) on old kernels.
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- 28 2月, 2014 1 次提交
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由 Rich Felker 提交于
linux, gcc, etc. all use "sh" as the name for the superh arch. there was already some inconsistency internally in musl: the dynamic linker was searching for "ld-musl-sh.path" as its path file despite its own name being "ld-musl-superh.so.1". there was some sentiment in both directions as to how to resolve the inconsistency, but overall "sh" was favored.
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- 24 2月, 2014 1 次提交
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由 Bobby Bingham 提交于
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- 20 12月, 2013 1 次提交
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由 Rich Felker 提交于
the workaround/fallback code for supporting O_PATH file descriptors when the kernel lacks support for performing these operations on them caused EBADF to get replaced by ENOENT (due to missing entry in /proc/self/fd). this is unlikely to affect real-world code (calls that might yield EBADF are generally unsafe, especially in library code) but it was breaking some test cases. the fix I've applied is something of a tradeoff: it adds one syscall to these operations on kernels where the workaround is needed. the alternative would be to catch ENOENT from the /proc lookup and translate it to EBADF, but I want to avoid doing that in the interest of not touching/depending on /proc at all in these functions as long as the kernel correctly supports the operations. this is following the general principle of isolating hacks to code paths that are taken on broken systems, and keeping the code for correct systems completely hack-free.
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- 12 12月, 2013 1 次提交
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由 Szabolcs Nagy 提交于
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- 07 12月, 2013 1 次提交
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由 Rich Felker 提交于
this is purely a wrapper for close since Linux does not support EINTR semantics for the close syscall.
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- 02 11月, 2013 2 次提交
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由 Rich Felker 提交于
now that we're waiting for the exit status of the child process, the result can be conveyed in the exit status rather than via a pipe. since the error value might not fit in 7 bits, a table is used to translate possible meaningful error values to small integers.
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由 Rich Felker 提交于
I mistakenly assumed that clone without a signal produced processes that would not become zombies; however, waitpid with __WCLONE is required to release their pids.
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- 18 10月, 2013 1 次提交
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由 Rich Felker 提交于
as usual, this is needed to avoid fd leaks. as a better solution, the use of fds could possibly be replaced with mmap and a futex.
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- 13 10月, 2013 1 次提交
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由 Rich Felker 提交于
this fixes an issue reported by Daniel Thau whereby faccessat with the AT_EACCESS flag did not work in cases where the process is running suid or sgid but without root privileges. per POSIX, when the process does not have "appropriate privileges", setuid changes the euid, not the real uid, and the target uid must be equal to the current real or saved uid; if this condition is not met, EPERM results. this caused the faccessat child process to fail. using the setreuid syscall rather than setuid works. POSIX leaves it unspecified whether setreuid can set the real user id to the effective user id on processes without "appropriate privileges", but Linux allows this; if it's not allowed, there would be no way for this function to work.
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- 09 10月, 2013 1 次提交
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由 Rich Felker 提交于
based on patch by Michael Forney. at the same time, I've changed the if branch to be more clear, avoiding the comma operator. the underlying issue is that Linux always returns ERANGE when size is too short, even when it's zero, rather than returning EINVAL for the special case of zero as required by POSIX.
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- 01 9月, 2013 1 次提交
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由 Rich Felker 提交于
clone will pass the return value of the start function to SYS_exit anyway; there's no need to call the syscall directly.
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- 10 8月, 2013 1 次提交
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由 Rich Felker 提交于
the child process's stack may be insufficient size to support a signal frame, and there is no reason these signal handlers should run in the child anyway.
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- 03 8月, 2013 3 次提交
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由 Rich Felker 提交于
this is another case of the kernel syscall failing to support flags where it needs to, leading to horrible workarounds in userspace. this time the workaround requires changing uid/gid, and that's not safe to do in the current process. in the worst case, kernel resource limits might prevent recovering the original values, and then there would be no way to safely return. so, use the safe but horribly inefficient alternative: forking. clone is used instead of fork to suppress signals from the child. fortunately this worst-case code is only needed when effective and real ids mismatch, which mainly happens in suid programs.
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由 Rich Felker 提交于
on newer kernels, fchdir and fstat work anyway. this same fix should be applied to any other syscalls that are similarly affected. with this change, the current definitions of O_SEARCH and O_EXEC as O_PATH are mostly conforming to POSIX requirements. the main remaining issue is that O_NOFOLLOW has different semantics.
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由 Rich Felker 提交于
I intend to add more Linux workarounds that depend on using these pathnames, and some of them will be in "syscall" functions that, from an anti-bloat standpoint, should not depend on the whole snprintf framework.
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- 09 7月, 2013 2 次提交
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由 Rich Felker 提交于
also clean up, optimize, and simplify the code, removing branches by simply pre-setting the result string to an empty string, which will be preserved if other operations fail.
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由 Rich Felker 提交于
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- 25 3月, 2013 1 次提交
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由 Rich Felker 提交于
SYS_pipe is not usable directly in general, since mips has a very broken calling convention for the pipe syscall. instead, just call the function, so that the mips-specific ugliness is isolated in mips/pipe.s and not copied elsewhere.
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- 04 2月, 2013 1 次提交
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由 Rich Felker 提交于
also, don't waste code/time on F_GETFL since pipes always have blank flags initially (at least on old kernels, which are all this fallback code matters for).
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- 11 12月, 2012 1 次提交
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由 Rich Felker 提交于
this bug seems to have caused any failure by pipe2 on such systems to set errno to 1, rather than the proper error code.
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- 25 10月, 2012 1 次提交
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由 Rich Felker 提交于
1. don't open /dev/null just as a basis to copy flags; use shared __fmodeflags function to get the right file flags for the mode. 2. handle the case (probably invalid, but whatever) case where the original stream's file descriptor was closed; previously, the logic re-closed it. 3. accept the "e" mode flag for close-on-exec; update dup3 to fallback to using dup2 so we can simply call __dup3 instead of putting fallback logic in freopen itself.
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- 19 10月, 2012 1 次提交
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由 Rich Felker 提交于
since we target systems without overcommit, special care should be taken that system() and popen(), like posix_spawn(), do not fail in processes whose commit charges are too high to allow ordinary forking. this in turn requires special precautions to ensure that the parent process's signal handlers do not end up running in the shared-memory child, where they could corrupt the state of the parent process. popen has also been updated to use pipe2, so it does not have a fd-leak race in multi-threaded programs. since pipe2 is missing on older kernels, (non-atomic) emulation has been added. some silly bugs in the old code should be gone too.
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- 30 9月, 2012 1 次提交
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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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- 29 9月, 2012 1 次提交
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由 Rich Felker 提交于
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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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- 10 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
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- 09 9月, 2012 1 次提交
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由 Rich Felker 提交于
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- 07 9月, 2012 3 次提交
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由 Rich Felker 提交于
note that POSIX does not specify these functions as _Noreturn, because POSIX is aligned with C99, not the new C11 standard. when POSIX is eventually updated to C11, it will almost surely give these functions the _Noreturn attribute. for now, the actual _Noreturn keyword is not used anyway when compiling with a c99 compiler, which is what POSIX requires; the GCC __attribute__ is used instead if it's available, however. in a few places, I've added infinite for loops at the end of _Noreturn functions to silence compiler warnings. presumably __buildin_unreachable could achieve the same thing, but it would only work on newer GCCs and would not be portable. the loops should have near-zero code size cost anyway. like the previous _Noreturn commit, this one is based on patches contributed by philomath.
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由 Rich Felker 提交于
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
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由 Rich Felker 提交于
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- 11 7月, 2012 1 次提交
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由 Rich Felker 提交于
basically, this version of the code was obtained by starting with rdp's work from his ellcc source tree, adapting it to musl's build system and coding style, auditing the bits headers for discrepencies with kernel definitions or glibc/LSB ABI or large file issues, fixing up incompatibility with the old binutils from aboriginal linux, and adding some new special cases to deal with the oddities of sigaction and pipe syscall interfaces on mips. at present, minimal test programs work, but some interfaces are broken or missing. threaded programs probably will not link.
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- 20 6月, 2012 3 次提交
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由 Rich Felker 提交于
this was actually dangerously wrong, but presumably nobody uses this broken function anymore anyway..
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由 Rich Felker 提交于
if we eventually have build options, it might be nice to make an option to dummy this out again, in case anybody needs a system-wide disable for disk/ssd-thrashing, etc. that some daemons do when logging...
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由 Rich Felker 提交于
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- 25 5月, 2012 1 次提交
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由 Rich Felker 提交于
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- 02 3月, 2012 1 次提交
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由 Rich Felker 提交于
this is a popular extension some programs depend on, and by using a temporary buffer and strdup rather than malloc prior to the syscall, i've avoided the dependency on free and thus minimized the bloat cost of supporting this feature.
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- 26 9月, 2011 1 次提交
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由 Rich Felker 提交于
the changes to syscall_ret are mostly no-ops in the generated code, just cleanup of type issues and removal of some implementation-defined behavior. the one exception is the change in the comparison value, which is fixed so that 0xf...f000 (which in principle could be a valid return value for mmap, although probably never in reality) is not treated as an error return.
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- 22 9月, 2011 1 次提交
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由 Rich Felker 提交于
the arm syscall abi requires 64-bit arguments to be aligned on an even register boundary. these new macros facilitate meeting the abi requirement without imposing significant ugliness on the code.
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