loop.c: klibc specific fix for ioctl argument 3

Fixing:
| loop.c:20:14: error: too few arguments to function 'ioctl'
|   int devnr = ioctl(fd, LOOP_CTL_GET_FREE);
|               ^
| In file included from loop.c:6:0:
| /oe/oe-core/build/tmp-glibc/sysroots/poodle/usr/lib/klibc/include/unistd.h:111:14: note: declared here
|  __extern int ioctl(int, int, void *);
|               ^
| loop.c: In function 'losetup':
| loop.c:48:12: warning: passing argument 3 of 'ioctl' makes pointer from integer without a cast
|   int res = ioctl(loopfd, LOOP_SET_FD, filefd);
|             ^
| In file included from loop.c:6:0:
| /oe/oe-core/build/tmp-glibc/sysroots/poodle/usr/lib/klibc/include/unistd.h:111:14: note: expected 'void *' but argument is of type 'int'
|  __extern int ioctl(int, int, void *);
|               ^
| make: *** [loop.o] Error 1

Signed-off-by: Andrea Adami <[email protected]>

Maarten ter Huurne <[email protected]>:
Add comment in code that we pass 3rd arg for klibc.
Add intptr_t typecast to suppress warning on systems where
sizeof(int) < sizeof(void *).

Author: andrea-adami

loop.c

@@ -1,5 +1,6 @@
 #include <fcntl.h>
 #include <linux/loop.h>
+#include <stdint.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -9,6 +10,8 @@
 #include "loop.h"
 
 
+// Note: klibc demands the third ioctl arg to be a void*.
+
 int logetfree(void)
 {
 	int fd = open("/dev/loop-control", O_RDWR);
@@ -17,7 +20,7 @@ int logetfree(void)
 		return -1;
 	}
 
-	int devnr = ioctl(fd, LOOP_CTL_GET_FREE);
+	int devnr = ioctl(fd, LOOP_CTL_GET_FREE, NULL);
 	if (devnr < 0) {
 		WARNING("Failed to acquire free loop device: %d\n", devnr);
 	} else {
@@ -45,7 +48,7 @@ int losetup(const char *loop, const char *file)
 		return -1;
 	}
 
-	int res = ioctl(loopfd, LOOP_SET_FD, filefd);
+	int res = ioctl(loopfd, LOOP_SET_FD, (void *)(intptr_t)filefd);
 	if (res < 0) {
 		ERROR("Cannot setup loop device '%s': %d\n", loop, res);
 	}