Rich Felker
a5ba2d7507
these changes are motivated by a functionally similar patch by Hauke Mehrtens to address the needs of the new mips vdso clock_gettime, which wrongly fails with ENOSYS rather than falling back to making a syscall for clock ids it cannot handle from userspace. in the process of preparing to handle that case, it was noticed that the old clock_gettime use of the vdso was actually wrong with respect to error handling -- the tail call to the vdso function failed to set errno and instead returned an error code. since tail calls to vdso are no longer possible and since the plain syscall code is now needed as a fallback path anyway, it does not make sense to use a function pointer to call the plain syscall code path. instead, it's inlined at the end of the main clock_gettime function. the new code also avoids the need to test for initialization of the vdso function pointer by statically initializing it to a self-init function, and eliminates redundant loads from the volatile pointer object. finally, the use of a_cas_p on an object of type other than void *, which is not permitted aliasing, is replaced by using an object with the correct type and casting the value.
musl libc
musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.
The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.
For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/