path: root/src/mman
AgeCommit message (Collapse)AuthorLines
2013-12-12include cleanups: remove unused headers and add feature test macrosSzabolcs Nagy-2/+0
2013-09-15support configurable page size on mips, powerpc and microblazeSzabolcs Nagy-1/+1
PAGE_SIZE was hardcoded to 4096, which is historically what most systems use, but on several archs it is a kernel config parameter, user space can only know it at execution time from the aux vector. PAGE_SIZE and PAGESIZE are not defined on archs where page size is a runtime parameter, applications should use sysconf(_SC_PAGE_SIZE) to query it. Internally libc code defines PAGE_SIZE to libc.page_size, which is set to aux[AT_PAGESZ] in __init_libc and early in __dynlink as well. (Note that libc.page_size can be accessed without GOT, ie. before relocations are done) Some fpathconf settings are hardcoded to 4096, these should be actually queried from the filesystem using statfs.
2013-07-20fix shm_open wrongly being cancellableRich Felker-1/+6
2013-06-27disallow creation of objects larger than PTRDIFF_MAX via mmapRich Felker-0/+5
internally, other parts of the library assume sizes don't overflow ssize_t and/or ptrdiff_t, and the way this assumption is made valid is by preventing creating of such large objects. malloc already does so, but the check was missing from mmap. this is also a quality of implementation issue: even if the implementation internally could handle such objects, applications could inadvertently invoke undefined behavior by subtracting pointers within an object. it is very difficult to guard against this in applications, so a good implementation should simply ensure that it does not happen.
2012-12-20clean up and fix logic for making mmap fail on invalid/unsupported offsetsRich Felker-3/+7
the previous logic was assuming the kernel would give EINVAL when passed an invalid address, but instead with MAP_FIXED it was giving EPERM, as it considered this an attempt to map over kernel memory. instead of trying to get the kernel to do the rigth thing, the new code just handles the error in userspace. I have also cleaned up the code to use a single mask to check for invalid low bits and unsupported high bits, so it's simpler and more clearly correct. the old code was actually wrong for sizeof(long) smaller than sizeof(off_t) but not equal to 4; now it should be correct for all possibilities. for 64-bit systems, the low-bits test is new and extraneous (the kernel should catch the error anyway when the mmap2 syscall is not used), but it's cheap anyway. if this is an issue, the OFF_MASK definition could be tweaked to omit the low bits when SYS_mmap2 is not defined.
2012-09-30overhaul sem_openRich Felker-3/+3
this function was overly complicated and not even obviously correct. avoid using openat/linkat just like in shm_open, and instead expand pathname using code shared with shm_open. remove bogus (and dangerous, with priorities) use of spinlocks. this commit also heavily streamlines the code and ensures there are no failure cases that can happen after a new semaphore has been created in the filesystem, since that case is unreportable.
2012-09-30clean up, bugfixes, and general improvement for shm_open/shm_unlinkRich Felker-30/+28
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
2012-09-09mincore syscall wrapperRich Felker-0/+8
2011-09-27process-shared barrier support, based on discussion with bdonlanRich Felker-3/+21
this implementation is rather heavy-weight, but it's the first solution i've found that's actually correct. all waiters actually wait twice at the barrier so that they can synchronize exit, and they hold a "vm lock" that prevents changes to virtual memory mappings (and blocks pthread_barrier_destroy) until all waiters are finished inspecting the barrier. thus, it is safe for any thread to destroy and/or unmap the barrier's memory as soon as pthread_barrier_wait returns, without further synchronization.
2011-06-29work around linux bug in mprotectRich Felker-1/+5
per POSIX: The mprotect() function shall change the access protections to be that specified by prot for those whole pages containing any part of the address space of the process starting at address addr and continuing for len bytes. on the other hand, linux mprotect fails with EINVAL if the base address and/or length is not page-aligned, so we have to align them before making the syscall.
2011-04-20fix missing include in posix_madvise.c (compile error)Rich Felker-0/+1
2011-04-20support posix_madvise (previous a stub)Rich Felker-1/+3
the check against MADV_DONTNEED to because linux MADV_DONTNEED semantics conflict dangerously with the POSIX semantics
2011-04-06consistency: change all remaining syscalls to use SYS_ rather than __NR_ prefixRich Felker-1/+1
2011-03-20global cleanup to use the new syscall interfaceRich Felker-11/+11
2011-03-03implement POSIX shared memoryRich Felker-0/+42
2011-02-13cleaning up syscalls in preparation for x86_64 portRich Felker-0/+4
- hide all the legacy xxxxxx32 name cruft in syscall.h so the actual source files can be clean and uniform across all archs. - cleanup llseek/lseek and mmap2/mmap handling for 32/64 bit systems - alternate implementation for nice if the target lacks nice syscall
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker-0/+107