view doc/posix-functions/strstr.texi @ 13772:1d8a613275c6

memmem, strstr, strcasestr: fix bug with long periodic needle * lib/str-two-way.h (two_way_long_needle): Avoid bug with long periodic needle having false positive. * m4/memmem.m4 (gl_FUNC_MEMMEM_SIMPLE): Detect bug in glibc 2.12 and cygwin 1.7.7. (gl_FUNC_MEMMEM): Be more pessimistic when cross-compiling. * m4/strcasestr.m4 (gl_FUNC_STRCASESTR_SIMPLE) (gl_FUNC_STRCASESTR): Likewise. * m4/strstr.m4 (gl_FUNC_STRSTR_SIMPLE, gl_FUNC_STRSTR): Likewise. * tests/test-memmem.c (main): Expose the bug. * tests/test-strcasestr.c (main): Likewise. * tests/test-strstr.c (main): Likewise. * tests/test-c-strcasestr.c (main): Likewise. * doc/glibc-functions/memmem.texi (memmem): Document the bug. * doc/posix-functions/strstr.texi (strstr): Likewise. * doc/glibc-functions/strcasestr.texi (strcasestr): Likewise. Reported via http://sourceware.org/bugzilla/show_bug.cgi?id=12092 Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Tue, 05 Oct 2010 16:39:32 -0600
parents bb0ceefd22dc
children c65fd41437cf
line wrap: on
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@node strstr
@section @code{strstr}
@findex strstr

POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/strstr.html}

Gnulib module: strstr or strstr-simple

Portability problems fixed by either Gnulib module @code{strstr-simple}
or @code{strstr}:
@itemize
@item
This function can trigger memchr bugs on some platforms:
glibc 2.10.
@item
This function can trigger false positives for long periodic needles on
some platforms:
glibc 2.12, Cygwin 1.7.7.
@end itemize

Portability problems fixed by Gnulib @code{strstr}:
@itemize
@item
This function has quadratic instead of linear worst-case complexity on some
platforms:
glibc 2.8, MacOS X 10.3, FreeBSD 6.2, NetBSD 3.0, OpenBSD 4.0, AIX
5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
This function cannot work correctly on character strings in most multibyte
locales.  Gnulib provides an alternative function @code{mbsstr} that works
on character strings in all locales.
@end itemize