[RFC PATCH v2 0/2] util: Add thread-safe qemu_strerror() function

[Yohei Kojima]

This patch series adds qemu_strerror() function, which is thread-safe
version of the libc strerror(). The first patch introduces the
qemu_strerror() function, and the second patch replaces strerror()
function in linux-user/* with qemu_strerror() function.

Because it involves thread safety, qemu_strerror() should be tested
carefully. But before adding tests, I want to ask (1) will this patch be
acceptable to QEMU project after adding tests, (2) where and how
qemu_strerror() should be tested.

(1) means that: is my approach too complicated to solve potential
thread-unsafe implementation of strerror()? Although strerror() is not
guaranteed to be thread-safe, glibc implements thread-safe strerror().
We have to consider the balance between maintenance costs and potential
risks.

(2) means that: is tests/unit/test-cutils.c a good place for tests?
Because the behavior of qemu_strerror() is changed by the feature test
macros, the tests should be run with different test macros, hopefully
in different OSs.

Note that strerror_r() function called by qemu_strerror() has
different return types between architectures because of the historical
reason. qemu_strerror() handles both the newer POSIX strerror() and the
older POSIX strerror().

All tests except for skipped ones are passed in my environment (x86_64
linux).

Yohei Kojima (2):
  util: Add thread-safe qemu_strerror() function
  linux-user: replace strerror() function to the thread safe
    qemu_strerror()

 include/qemu/cutils.h | 20 +++++++++++++++++++
 linux-user/elfload.c  |  4 ++--
 linux-user/main.c     |  4 ++--
 linux-user/syscall.c  |  2 +-
 util/cutils.c         | 45 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 70 insertions(+), 5 deletions(-)

-- 
2.39.2