cvs commit: src/lib/libc/stdio fdopen.c fopen.c freopen.c
jhb at freebsd.org
Wed Feb 27 20:18:55 UTC 2008
On Wednesday 27 February 2008 02:02:03 pm John Baldwin wrote:
> jhb 2008-02-27 19:02:02 UTC
> FreeBSD src repository
> Modified files:
> lib/libc/stdio fdopen.c fopen.c freopen.c
> File descriptors are an int, but our stdio FILE object uses a short to
> them. Thus, any fd whose value is greater than SHRT_MAX is handled
> incorrectly (the short value is sign-extended when converted to an int).
> An unpleasant side effect is that if fopen() opens a file and gets a
> backing fd that is greater than SHRT_MAX, fclose() will fail and the file
> descriptor will be leaked. Better handle this by fixing fopen(),
> and freopen() to fail attempts to use a fd greater than SHRT_MAX with
> At some point in the future we should look at expanding the file
> in FILE to an int, but that is a bit complicated due to ABI issues.
To reproduce, open 32k fd's and then invoke gethostbyname() with 'files'
enabled in nsswitch.conf for host lookups. A fd on /etc/hosts will be leaked
for each invocation of gethostbyname().
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