1 files changed, 71 insertions, 0 deletions
diff --git a/lib/libc/gen/check_utility_compat.c b/lib/libc/gen/check_utility_compat.c
new file mode 100644
index 000000000000..04c594b52665
--- /dev/null
+++ b/lib/libc/gen/check_utility_compat.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2002 Massachusetts Institute of Technology
+ *
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose and without fee is hereby
+ * granted, provided that both the above copyright notice and this
+ * permission notice appear in all copies, that both the above
+ * copyright notice and this permission notice appear in all
+ * supporting documentation, and that the name of M.I.T. not be used
+ * in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  M.I.T. makes
+ * no representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
+ * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
+ * SHALL M.I.T. 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * I din't use "namespace.h" here because none of the relevant utilities
+ * are threaded, so I'm not concerned about cancellation points or other
+ * niceties.
+ */
+#include <sys/limits.h>
+
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define	_PATH_UTIL_COMPAT	"/etc/compat-FreeBSD-4-util"
+#define	_ENV_UTIL_COMPAT	"_COMPAT_FreeBSD_4"
+
+int
+check_utility_compat(const char *utility)
+{
+	char buf[PATH_MAX];
+	char *p, *bp;
+	int len;
+
+	if ((p = getenv(_ENV_UTIL_COMPAT)) != NULL) {
+		strlcpy(buf, p, sizeof buf);
+	} else {
+		if ((len = readlink(_PATH_UTIL_COMPAT, buf, sizeof(buf) - 1)) < 0)
+			return 0;
+		buf[len] = '\0';
+	}
+	if (buf[0] == '\0')
+		return 1;
+
+	bp = buf;
+	while ((p = strsep(&bp, ",")) != NULL) {
+		if (strcmp(p, utility) == 0)
+			return 1;
+	}
+	return 0;
+}