[libvirt] PATCH: 15/25: Prohibit non-threadsafe POSIX apis
Richard W.M. Jones
rjones at redhat.com
Thu Jan 15 17:31:35 UTC 2009
On Tue, Jan 13, 2009 at 05:44:51PM +0000, Daniel P. Berrange wrote:
> There are a huge list of functions in POSIX which are not
> safe to use from multiple threads currently. I generated
> the list by looking at all libc symbol exports for variants
> which have a parallel _r symbol.
>
> nm -D --defined-only /lib/libc.so.6 \
> | grep '_r$' \
> | awk '{print $3}' \
> | grep -v __ \
> | grep -v qsort \
> | grep -v readdir \
> | sort \
> | uniq \
> | sed -e 's/_r//'
>
> The qsort one is a red herring, since you only need qsort_r if
> you need to pass a extra 'void * opaque' data blob to your sort
> function - we don't, so don't need qsort_r.
>
> The readdir one is also unneccessary, since reading from a single
> DIR* is safe from a single thread. readdir_r is also horrific
>
> http://womble.decadentplace.org.uk/readdir_r-advisory.html
>
>
> This patch adds a 'make sc_prohibit_nonrentrant' rule to the
> 'syntax-check' for these forbidden functions.
>
> .x-sc_prohibit_nonreentrant | 8 ++++
> Makefile.am | 2 +
> Makefile.maint | 11 +++++
> Makefile.nonreentrant | 85 ++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 106 insertions(+)
Yup, perfect, +1.
Rich.
--
Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones
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