aad50fcd791e009961621ddfbe3d4c245fd689a3
__tls_get_addr should not be called with an invalid TLS module id of 0. in practice it probably "works", returning the DTV length as if it were a pointer, and the callback should probably not inspect dlpi_tls_data in this case, but it's likely that some real-world callbacks use a check on dlpi_tls_data being non-null, rather than on dlpi_tls_modid being nonzero, to conclude that the module has TLS.
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/