Add fallback implementation of strndup()

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
Linux test code fixed by: Keith Packard <keithp@keithp.com>

configure.ac

@@ -218,6 +218,8 @@ AC_CHECK_FUNCS([geteuid getuid link memmove memset mkstemp strchr strrchr \
 		strtol getopt getopt_long vsnprintf walkcontext backtrace \
 		getisax getzoneid shmctl64 strcasestr ffs vasprintf])
 AC_FUNC_ALLOCA
+AC_CHECK_FUNCS([strndup], [HAVE_STRNDUP=yes], [HAVE_STRNDUP=no])
+AM_CONDITIONAL(NEED_STRNDUP, [test x$HAVE_STRNDUP = xno])
 dnl Old HAS_* names used in os/*.c.
 AC_CHECK_FUNC([getdtablesize],
 	AC_DEFINE(HAS_GETDTABLESIZE, 1, [Have the 'getdtablesize' function.]))

include/dix-config.h.in

@@ -190,6 +190,9 @@
 /* Define to 1 if you have the <string.h> header file. */
 #undef HAVE_STRING_H
 
+/* Define to 1 if you have the `strndup' function. */
+#undef HAVE_STRNDUP
+
 /* Define to 1 if you have the `strrchr' function. */
 #undef HAVE_STRRCHR
 

include/os.h

@@ -492,6 +492,10 @@ extern _X_EXPORT size_t strlcpy(char *dst, const char *src, size_t siz);
 extern _X_EXPORT size_t strlcat(char *dst, const char *src, size_t siz);
 #endif
 
+#ifndef HAVE_STRNDUP
+extern _X_EXPORT char * strndup(const char *str, size_t n);
+#endif
+
 /* Logging. */
 typedef enum _LogParameter {
     XLOG_FLUSH,

os/Makefile.am

@@ -41,6 +41,10 @@ if NEED_STRLCAT
 libos_la_SOURCES += $(STRLCAT_SRCS)
 endif
 
+if NEED_STRNDUP
+libos_la_SOURCES += $(STRNDUP_SRCS)
+endif
+
 EXTRA_DIST = $(SECURERPC_SRCS) $(INTERNALMALLOC_SRCS) \
      $(XDMCP_SRCS) $(STRLCAT_SRCS)
 

os/strndup.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include "os.h"
+
+char *
+strndup(const char *str, size_t n)
+{
+	size_t len;
+	char *copy;
+
+	for (len = 0; len < n && str[len]; len++)
+		continue;
+
+	if ((copy = malloc(len + 1)) == NULL)
+		return (NULL);
+	memcpy(copy, str, len);
+	copy[len] = '\0';
+	return (copy);
+}

test/.gitignore

@@ -4,3 +4,4 @@ xtest
 list
 misc
 fixes
+string

test/Makefile.am

@@ -1,6 +1,6 @@
 if ENABLE_UNIT_TESTS
 SUBDIRS= . xi2
-noinst_PROGRAMS = xkb input xtest list misc fixes xfree86
+noinst_PROGRAMS = xkb input xtest list misc fixes xfree86 string
 check_LTLIBRARIES = libxservertest.la
 
 TESTS=$(noinst_PROGRAMS)

test/string.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * Tests for fallback implementations of string handling routines
+ * provided in os/ subdirectory for some platforms.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <assert.h>
+#include "os.h"
+
+/* Ensure we're testing our functions, even on platforms with libc versions */
+#include <string.h>
+#undef strndup
+#define strndup my_strndup
+char *
+strndup(const char *str, size_t n);
+
+#include "../os/strndup.c"
+
+static void strndup_checks(void)
+{
+    const char *sample="0123456789abcdef";
+    char *allofit;
+
+    char *firsthalf = strndup(sample, 8);
+    char *secondhalf = strndup(sample + 8, 8);
+
+    assert(strcmp(firsthalf,  "01234567") == 0);
+    assert(strcmp(secondhalf, "89abcdef") == 0);
+
+    free(firsthalf);
+    free(secondhalf);
+
+    allofit = strndup(sample, 20);
+    assert(strcmp(allofit, sample) == 0);
+    free(allofit);
+}
+
+int main(int argc, char** argv)
+{
+    strndup_checks();
+
+    return 0;
+}