Aded kernelinfo(1) as a frontend of kernelinfo(2).

utils/Makefile

@@ -19,6 +19,7 @@ help \
 uptime \
 memstat \
 uname \
+kernelinfo \
 idle \
 editor \
 kill \

utils/kernelinfo.cpp

@@ -0,0 +1,59 @@
+#include <sys/kernelinfo.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <error.h>
+
+void usage(const char* argv0)
+{
+	printf("usage: %s <REQUEST> ...\n", argv0);
+	printf("Prints a kernel information string.\n");
+	printf("example: %s name\n", argv0);
+	printf("example: %s version\n", argv0);
+	printf("example: %s builddate\n", argv0);
+	printf("example: %s buildtime\n", argv0);
+}
+
+void help(const char* argv0)
+{
+	usage(argv0);
+}
+
+void version(const char* argv0)
+{
+	usage(argv0);
+}
+
+int main(int argc, char* argv[])
+{
+	const char* argv0 = argv[0];
+	if ( argc < 2 ) { usage(argv0); return 0; }
+	for ( int i = 1; i < argc; i++ )
+	{
+		if ( argv[i][0] != '-' ) { continue; }
+		if ( strcmp(argv[i], "--usage") == 0 ) { usage(argv0); return 0; }
+		if ( strcmp(argv[i], "--help") == 0 ) { help(argv0); return 0; }
+		if ( strcmp(argv[i], "--version") == 0 ) { version(argv0); return 0; }
+		fprintf(stderr, "%s: unknown option: %s\n", argv0, argv[i]);
+		return 1;
+	}
+	size_t bufsize = 32;
+	char* buf = (char*) malloc(bufsize);
+	if ( !buf ) { perror("malloc"); return 1; }
+	for ( int i = 1; i < argc; i++ )
+	{
+retry:
+		ssize_t ret = kernelinfo(argv[i], buf, bufsize);
+		if ( ret < 0 ) { error(1, errno, "kernelinfo(\"%s\")", argv[i]); }
+		if ( ret )
+		{
+			buf = (char*) realloc(buf, ret);
+			if ( !buf ) { perror("realloc"); return 1; }
+			bufsize = ret;
+			goto retry;
+		}
+		printf("%s\n", buf);
+	}
+	return 0;
+}