test to make sure the buffers used by the gethost*_r functions handle misaligned scratch buffers

test/inet/gethost_r-align.c

@@ -0,0 +1,50 @@
+/* Since the reentrant gethost functions take a char * buffer,
+ * we have to make sure they internally do not assume alignment.
+ * The actual return values are not relevant.  If the test fails,
+ * it'll be due to an alignment exception which means the test
+ * app is killed by the kernel.
+ */
+
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+int main(int argc, char *argv[])
+{
+	size_t i;
+	char buf[1024];
+	in_addr_t addr;
+
+	addr = inet_addr("127.0.0.1");
+
+	for (i = 0; i < sizeof(size_t) * 2; ++i) {
+		struct hostent hent, *hentres;
+		int ret, herr;
+
+		printf("Testing misalignment of %2zi bytes: ", i);
+
+		memset(&hent, 0x00, sizeof(hent));
+		ret = gethostent_r(&hent, buf + i, sizeof(buf) - i, &hentres, &herr);
+		printf("%sgethostent_r() ", (ret ? "!!!" : ""));
+
+		memset(&hent, 0x00, sizeof(hent));
+		ret = gethostbyname_r("localhost", &hent, buf + i, sizeof(buf) - i, &hentres, &herr);
+		printf("%sgethostbyname_r() ", (ret ? "!!!" : ""));
+
+		memset(&hent, 0x00, sizeof(hent));
+		ret = gethostbyname2_r("localhost", AF_INET, &hent, buf + i, sizeof(buf) - i, &hentres, &herr);
+		printf("%sgethostbyname2_r() ", (ret ? "!!!" : ""));
+
+		memset(&hent, 0x00, sizeof(hent));
+		ret = gethostbyaddr_r(&addr, sizeof(addr), AF_INET, &hent, buf + i, sizeof(buf) - i, &hentres, &herr);
+		printf("%sgethostbyaddr_r() ", (ret ? "!!!" : ""));
+
+		puts("OK!");
+	}
+
+	return 0;
+}