On Wed, May 09, 2012 at 10:45:52PM -0700, scott wrote:
> Here is a loadable kernel module for HTC Sensation XL (runnymede-
> crc-2.6.35).
>
> /*
> * mydebug.c
> * System Call sys_open dubugging
> */
>
> #include <linux/kernel.h> /* Needed for KERN_INFO */
> #include <linux/module.h> /* Needed by all modules */
> #include <linux/init.h> /* Needed for macros */
> #include <asm/unistd.h>
> #include <linux/linkage.h>
> #include <generated/autoconf.h>
> #include <linux/in.h>
> #include <linux/init_task.h>
> #include <linux/ip.h>
> #include <linux/kernel.h>
> #include <linux/kmod.h>
> #include <linux/mm.h>
>
> #include <linux/skbuff.h>
> #include <linux/workqueue.h>
>
> #include <linux/sched.h>
> #include <linux/stddef.h>
> #include <linux/string.h>
> #include <linux/syscalls.h>
> #include <linux/tcp.h>
> #include <linux/types.h>
> #include <linux/version.h>
>
>
> asmlinkage ssize_t (*orig_open)(const char *pathname, int flags);
>
> asmlinkage ssize_t hooked_open(const char *pathname, int flags)
> {
> printk(KERN_INFO "SYS_OPEN: %s\n", pathname);
> return orig_open(pathname, flags);
> }
>
> static int __init root_start(void)
> {
> unsigned long sys_addr = 0xc003b104; /* System.map */
> unsigned long *sys_call_table= (unsigned long *)sys_addr;
>
> orig_open = sys_call_table[__NR_open];
> sys_call_table[__NR_open] = hooked_open;
> return 0;
> }
>
> static void __exit root_stop(void)
> {
>
> unsigned long sys_addr = 0xc003b104;
> unsigned long *sys_call_table= (unsigned long *)sys_addr;
>
> sys_call_table[__NR_open] = &orig_open;
> }
>
> module_init(root_start);
> module_exit(root_stop);
>
> -------
> When I buid it, the error shows below,
>
> make -C /home/scott/runnymede-crc-2.6.35/ M=`pwd` ARCH=arm
> CROSS_COMPILE=~/android-ndk-r7b/toolchains/arm-linux-androideabi-4.4.3/
> prebuilt/linux-x86/bin/arm-linux-androideabi- modules
> make[1]: Entering directory `<home>/runnymede-crc-2.6.35'
> CC [M] /<home>/workspace/debugkit/mydebug.o
> cc1: warnings being treated as errors
> /<home>/workspace/debugkit/mydebug.c: In function 'root_start':
> /<home>/workspace/debugkit/mydebug.c:44: error: assignment makes
> pointer from integer without a cast
> /<home>/workspace/debugkit/mydebug.c:45: error: assignment makes
> integer from pointer without a cast
> /<home>/workspace/debugkit/mydebug.c: In function 'root_stop':
> /<home>/workspace/debugkit/mydebug.c:55: error: assignment makes
> integer from pointer without a cast
> make[2]: *** [/<home>/workspace/debugkit/mydebug.o] Error 1
> make[1]: *** [_module_/<home>/workspace/debugkit] Error 2
> make[1]: Leaving directory `/home/scott/runnymede-crc-2.6.35'
> make: *** [default] Error 2
>
> Anyone can give me a help for it?
>
> --
> unsubscribe: android-kernel+unsubscr...@googlegroups.com
> website: http://groups.google.com/group/android-kernel
First of all your build environment make all warnings into errors
(-Werror) and compiler has already worn you about that: "cc1: warnings
being treated as errors",
To understand reasons for these warnings quickly just bare in mind that
sys_call_table is array of unsigned long, but you are trying to
substitute some entries with pointers to functions and vise versa ;)
Hope this helps.
Best wishes
Vladimir Murzin
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