Date: Tue, 26 May 2015 21:16:08 +0000 (UTC) From: Ed Maste <emaste@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r283584 - in head: contrib/netbsd-tests/lib/libc/string lib/libc/string Message-ID: <201505262116.t4QLG8HK089130@svn.freebsd.org>
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Author: emaste Date: Tue May 26 21:16:07 2015 New Revision: 283584 URL: https://svnweb.freebsd.org/changeset/base/283584 Log: memmem(3): empty little string matches the beginning of the big string This function originated in glibc, and this matches their behaviour (and NetBSD, OpenBSD, and musl). An empty big string (arg "l") is handled by the existing l_len < s_len test. Reviewed by: bapt, ngie Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D2657 Modified: head/contrib/netbsd-tests/lib/libc/string/t_memmem.c head/lib/libc/string/memmem.3 head/lib/libc/string/memmem.c Modified: head/contrib/netbsd-tests/lib/libc/string/t_memmem.c ============================================================================== --- head/contrib/netbsd-tests/lib/libc/string/t_memmem.c Tue May 26 21:12:02 2015 (r283583) +++ head/contrib/netbsd-tests/lib/libc/string/t_memmem.c Tue May 26 21:16:07 2015 (r283584) @@ -75,7 +75,7 @@ ATF_TC_HEAD(memmem_basic, tc) ATF_TC_BODY(memmem_basic, tc) { -#if defined(__darwin__) || defined(__FreeBSD__) +#if defined(__darwin__) expect(memmem(b2, lb2, p0, lp0) == NULL); expect(memmem(b0, lb0, p0, lp0) == NULL); #else Modified: head/lib/libc/string/memmem.3 ============================================================================== --- head/lib/libc/string/memmem.3 Tue May 26 21:12:02 2015 (r283583) +++ head/lib/libc/string/memmem.3 Tue May 26 21:16:07 2015 (r283584) @@ -26,7 +26,7 @@ .\" .\" $FreeBSD$ .\" -.Dd August 24, 2005 +.Dd May 26, 2015 .Dt MEMMEM 3 .Os .Sh NAME @@ -51,14 +51,12 @@ in the byte string .Fa big . .Sh RETURN VALUES If -.Fa big_len -is smaller than -.Fa little_len , -if .Fa little_len -is 0, if -.Fa big_len -is 0 or if +is zero +.Fa big +is returned (that is, an empty little is deemed to match at the beginning of +big); +if .Fa little occurs nowhere in .Fa big , @@ -84,3 +82,11 @@ function first appeared in .Sh BUGS This function was broken in Linux libc up to and including version 5.0.9 and in GNU libc prior to version 2.1. +Prior to +.Fx 11.0 +.Nm +returned +.Dv NULL +when +.Fa little_len +equals 0. Modified: head/lib/libc/string/memmem.c ============================================================================== --- head/lib/libc/string/memmem.c Tue May 26 21:12:02 2015 (r283583) +++ head/lib/libc/string/memmem.c Tue May 26 21:16:07 2015 (r283584) @@ -42,9 +42,9 @@ memmem(const void *l, size_t l_len, cons const char *cl = (const char *)l; const char *cs = (const char *)s; - /* we need something to compare */ - if (l_len == 0 || s_len == 0) - return NULL; + /* empty "s" matches the beginning of "l" */ + if (s_len == 0) + return (void *)cl; /* "s" must be smaller or equal to "l" */ if (l_len < s_len)
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