split out tracks to individual object files

In order to reduce the memory requirements for building the
kernel module, build each track into an object file individually.

For this purpose, each "track object" exports the data array and its
length explicitly, which can then be used from netcat_main.c.

Signed-off-by: Philipp A. Hartmann <pah@qo.cx>

Makefile

@@ -1,5 +1,11 @@
 obj-m += netcat.o
 netcat-y = netcat_main.o
+netcat-y+= tracks/trk1.o
+netcat-y+= tracks/trk2.o
+netcat-y+= tracks/trk3.o
+netcat-y+= tracks/trk4.o
+netcat-y+= tracks/trk5.o
+netcat-y+= tracks/trk6.o
 
 KERNELDIR	?=  /lib/modules/$(shell uname -r)/build
 PWD		:= $(shell pwd)

netcat_main.c

@@ -7,22 +7,6 @@
 #include <linux/miscdevice.h>
 #include <linux/slab.h>
 
-/* Brandon's compiler crashes unless we include them in
- * this order.
- *
- *   __                               __
- * _/  |_  ____   ____ _____    _____/  |_
- * \   __\/ __ \ /    \\__  \ _/ ___\   __\
- *  |  | \  ___/|   |  \/ __ \\  \___|  |
- *  |__|  \___  >___|  (____  /\___  >__|
- *            \/     \/     \/     \/
- */
-#include "tracks/trk4.c"
-#include "tracks/trk5.c"
-#include "tracks/trk6.c"
-#include "tracks/trk1.c"
-#include "tracks/trk2.c"
-#include "tracks/trk3.c"
 
 #define DEVICE_NAME "netcat"	/* Dev name as it appears in /proc/devices   */
 
@@ -32,6 +16,20 @@ struct netcat {
 	int	current_track;
 };
 
+extern char netcat_cpi_trk1[];
+extern char netcat_cpi_trk2[];
+extern char netcat_cpi_trk3[];
+extern char netcat_cpi_trk4[];
+extern char netcat_cpi_trk5[];
+extern char netcat_cpi_trk6[];
+
+extern unsigned long netcat_cpi_trk1_len;
+extern unsigned long netcat_cpi_trk2_len;
+extern unsigned long netcat_cpi_trk3_len;
+extern unsigned long netcat_cpi_trk4_len;
+extern unsigned long netcat_cpi_trk5_len;
+extern unsigned long netcat_cpi_trk6_len;
+
 static char *tracks[] = {netcat_cpi_trk1,
 			 netcat_cpi_trk2,
 			 netcat_cpi_trk3,
@@ -46,12 +44,12 @@ static char *tracknames[] = {"Interrupt 0x7f",
 			 "Interrupt 0xbb",
 			 "Approximating the Circumference of the Earth"};
 
-static unsigned long tracklens[] = {NETCAT_CPI_TRK1_LEN,
-				    NETCAT_CPI_TRK2_LEN,
-				    NETCAT_CPI_TRK3_LEN,
-				    NETCAT_CPI_TRK4_LEN,
-				    NETCAT_CPI_TRK5_LEN,
-				    NETCAT_CPI_TRK6_LEN};
+static unsigned long *tracklens[] = {&netcat_cpi_trk1_len,
+				     &netcat_cpi_trk2_len,
+				     &netcat_cpi_trk3_len,
+				     &netcat_cpi_trk4_len,
+				     &netcat_cpi_trk5_len,
+				     &netcat_cpi_trk6_len};
 
 
 static int device_open(struct inode *inode, struct file *file)
@@ -92,7 +90,7 @@ static ssize_t device_read(struct file *file,
 		netcat->first_time = false;
 	}
 
-	if (netcat->msg - tracks[current_track] >= tracklens[current_track]) {
+	if (netcat->msg - tracks[current_track] >= *tracklens[current_track]) {
 		/* End of Track.  Skip to next track, or finish if it's track 6 */
 		current_track++;
 		if (current_track >= 6)
@@ -105,7 +103,7 @@ static ssize_t device_read(struct file *file,
 
 	while (length &&
 		(netcat->msg - tracks[current_track]) <
-		 tracklens[current_track]) {
+		 *tracklens[current_track]) {
 		put_user(*(netcat->msg++), buffer++);
 
 		length--;

tracks/trk1.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK1_LEN 624344
-static char netcat_cpi_trk1[] = {
+char netcat_cpi_trk1[] = {
 
 #include "trk1data.h"
 
 };
+unsigned long netcat_cpi_trk1_len = NETCAT_CPI_TRK1_LEN;

tracks/trk2.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK2_LEN 11659615
-static char netcat_cpi_trk2[] = {
+char netcat_cpi_trk2[] = {
 
 #include "trk2data.h"
 
 };
+unsigned long netcat_cpi_trk2_len = NETCAT_CPI_TRK2_LEN;

tracks/trk3.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK3_LEN 829971
-static char netcat_cpi_trk3[] = {
+char netcat_cpi_trk3[] = {
 
 #include "trk3data.h"
 
 };
+unsigned long netcat_cpi_trk3_len = NETCAT_CPI_TRK3_LEN;

tracks/trk4.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK4_LEN 10788741
-static char netcat_cpi_trk4[] = {
+char netcat_cpi_trk4[] = {
 
 #include "trk4data.h"
 
 };
+unsigned long netcat_cpi_trk4_len = NETCAT_CPI_TRK4_LEN;

tracks/trk5.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK5_LEN 858054
-static char netcat_cpi_trk5[] = {
+char netcat_cpi_trk5[] = {
 
 #include "trk5data.h"
 
 };
+unsigned long netcat_cpi_trk5_len = NETCAT_CPI_TRK5_LEN;

tracks/trk6.c

@@ -1,6 +1,7 @@
 #define NETCAT_CPI_TRK6_LEN 13025371
-static char netcat_cpi_trk6[] = {
+char netcat_cpi_trk6[] = {
 
 #include "trk6data.h"
 
 };
+unsigned long netcat_cpi_trk6_len = NETCAT_CPI_TRK6_LEN;