mkuboot: produce raw binaries if requested

mkuboot generates images bootable in u-boot.  These images
contain a header and the actual kernel object code.

This program was improved so it can embed kernel symbols
and the ramdisk into the generated image, like a bootloader
would do when booting from an actual ELF kernel.

Sometimes having a blob with ksyms+ramdisk _without_ the
image header for u-boot can be useful.  This change add
a flag 'r' which indicates that it should output the binary
in raw mode, without the u-boot headers.

"sounds fine then." drahn@

usr.sbin/mkuboot/mkuboot.8

@@ -27,6 +27,7 @@
 .Op Fl l Ar loadaddr
 .Op Fl n Ar name
 .Op Fl o Ar os
+.Op Fl r
 .Op Fl t Ar type
 .Ar infile outfile
 .Sh DESCRIPTION
@@ -56,6 +57,8 @@ can be either
 .Dq Linux
 or
 .Dq OpenBSD .
+.It Fl r
+Produce a raw binary instead of a U-Boot image.
 .It Fl t Ar type
 Sets the type of the object to be loaded.
 For a list of valid arguments, see below.

usr.sbin/mkuboot/mkuboot.c

@@ -144,17 +144,20 @@ main(int argc, char *argv[])
 	const char *os = "OpenBSD";
 	const char *type = "kernel";
 	const char *imgname = "boot";
-	int ifd, ofd;
+	int ifd, ofd, raw = 0;
 	uint32_t fsize;
 	u_long crc;
 	int c, ep, load;
 
 	ep = load = 0;
-	while ((c = getopt(argc, argv, "a:e:l:n:o:t:")) != -1) {
+	while ((c = getopt(argc, argv, "a:e:l:n:o:rt:")) != -1) {
 		switch (c) {
 		case 'a':
 			arch = optarg;
 			break;
+		case 'r':
+			raw = 1;
+			break;
 		case 'e':
 			sscanf(optarg, "0x%x", &ep);
 			break;
@@ -233,7 +236,7 @@ main(int argc, char *argv[])
 	}
 
 	/* Write initial header. */
-	if (write(ofd, &ih, sizeof ih) != sizeof ih)
+	if (!raw && write(ofd, &ih, sizeof ih) != sizeof ih)
 		err(1, "%s", oname);
 
 	/* Write data, calculating the data CRC as we go. */
@@ -270,7 +273,7 @@ main(int argc, char *argv[])
 	/* Write finalized header. */
 	if (lseek(ofd, 0, SEEK_SET) != 0)
 		err(1, "%s", oname);
-	if (write(ofd, &ih, sizeof ih) != sizeof ih)
+	if (!raw && write(ofd, &ih, sizeof ih) != sizeof ih)
 		err(1, "%s", oname);
 
 	return(0);