Re: [PATCH: sv.c] strchr() running amok in sv_vcatpvfn()

From: "Marcus Holland-Moritz" <mhx-perl@gmx.net>
Message-ID: <004a01c3331a$ec001320$3445eed9@R2D2>

p4raw-id: //depot/perl@19786

4 files changed, 3 insertions, 32 deletions

diff --git a/embed.fnc b/embed.fnc
index b3efd6e3d4..be08619186 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -1236,7 +1236,6 @@ s	|bool	|utf8_mg_pos_init	|SV *sv|MAGIC **mgp|STRLEN **cachep|I32 i|I32 *offsetp
 sM	|void	|sv_release_COW	|SV *sv|char *pvx|STRLEN cur|STRLEN len \
 				|U32 hash|SV *after
 #endif
-sn	|const char*|my_strnchr	|const char*	|int c	|size_t
 #endif
 
 #if defined(PERL_IN_TOKE_C) || defined(PERL_DECL_PROT)
diff --git a/embed.h b/embed.h
index cbef935267..5907e20af5 100644
--- a/embed.h
+++ b/embed.h
@@ -1886,9 +1886,6 @@
 #define sv_release_COW		S_sv_release_COW
 #endif
 #endif
-#ifdef PERL_CORE
-#define my_strnchr		S_my_strnchr
-#endif
 #endif
 #if defined(PERL_IN_TOKE_C) || defined(PERL_DECL_PROT)
 #ifdef PERL_CORE
@@ -4360,9 +4357,6 @@
 #define sv_release_COW(a,b,c,d,e,f)	S_sv_release_COW(aTHX_ a,b,c,d,e,f)
 #endif
 #endif
-#ifdef PERL_CORE
-#define my_strnchr		S_my_strnchr
-#endif
 #endif
 #if defined(PERL_IN_TOKE_C) || defined(PERL_DECL_PROT)
 #ifdef PERL_CORE
diff --git a/proto.h b/proto.h
index 880e269ab0..1f03b3bdaa 100644
--- a/proto.h
+++ b/proto.h
@@ -1186,7 +1186,6 @@ STATIC bool	S_utf8_mg_pos_init(pTHX_ SV *sv, MAGIC **mgp, STRLEN **cachep, I32 i
 #if defined(PERL_COPY_ON_WRITE)
 STATIC void	S_sv_release_COW(pTHX_ SV *sv, char *pvx, STRLEN cur, STRLEN len, U32 hash, SV *after);
 #endif
-STATIC const char*	S_my_strnchr(const char*, int c, size_t);
 #endif
 
 #if defined(PERL_IN_TOKE_C) || defined(PERL_DECL_PROT)
diff --git a/sv.c b/sv.c
index 9d6948e948..4e6d930ed2 100644
--- a/sv.c
+++ b/sv.c
@@ -8431,25 +8431,6 @@ Perl_sv_vsetpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
     sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, maybe_tainted);
 }
 
-/* my_strnchr(): private function for use in sv_vcatpvfn()
- *
- * Like strchr(), but allows to use strings that are not null-terminated.
- * The string length must be given instead and it _must_ be correct, as
- * the function does not stop searching when a '\0' is discovered.
- * This would also allow to explicitly search for '\0' characters.
- */
-
-STATIC
-const char *
-S_my_strnchr(const char* s, int c, size_t n)
-{
-    if (s)
-	for (; n > 0; n--, s++)
-	    if ((int)*s == c)
-		return s;
-    return NULL;
-}
-
 /* private function for use in sv_vcatpvfn via the EXPECT_NUMBER macro */
 
 STATIC I32
@@ -9348,11 +9329,9 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 	     p = SvEND(sv);
 	     *p = '\0';
 	}
-	/* Don't use strchr() here, because eptr does not necessarily point */
-	/* to a null-terminated string. E.g. with the format "%-10c", eptr  */
-	/* points to c (a single char on the stack), which makes strchr()   */
-	/* run amok over the stack until it eventually hits '\n' or '\0'.   */
-	if (left && ckWARN(WARN_PRINTF) && my_strnchr(eptr, '\n', elen) && 
+	/* Use memchr() instead of strchr(), as eptr is not guaranteed */
+	/* to point to a null-terminated string.                       */
+	if (left && ckWARN(WARN_PRINTF) && memchr(eptr, '\n', elen) && 
 	    (PL_op->op_type == OP_PRTF || PL_op->op_type == OP_SPRINTF)) 
 	    Perl_warner(aTHX_ packWARN(WARN_PRINTF),
 		"Newline in left-justified string for %sprintf",