i want to call open,write system calls from kernel space.
what i want to do actually is to wrap up open system call.I have done wrap up part of open system call using jprobes.
Now i want to write name of file being opened in another file say "/home/rahul/log" and code for it will be written in wrap-up part
since the wrap-up part of open system call also runs in kernel space i want to open and write file "/home/rahul/log" from kernel
space.
so the code in my wrap up routine in jprobe module will look like.
long my_sys_open(char*name,int flag,int mode)
{
int fd;
fs = get_fs(); /* save previous value */
set_fs (get_ds()); /* use kernel limit */
fd=sys_open("/home/rahul/log",O_CREAT,O_RDRW);
set_fs(fs);
fs = get_fs(); /* save previous value */
set_fs (get_ds()); /* use kernel limit */
fwrite(fd,name,strlen(name));
set_fs(fs);
jprobe_return();
return 0;
}
I will take care that recursion will not happen since i am calling sys_open from wrapper of sys_open
On Wed, Apr 28, 2010 at 8:10 AM, Joel Fernandes <agnel.joel@xxxxxxxxx> wrote:
On Wed, Apr 28, 2010 at 8:09 AM, Joel Fernandes <agnel.joel@xxxxxxxxx> wrote:
On Tue, Apr 27, 2010 at 7:55 AM, rahul patil <rahul.deshmukhpatil@xxxxxxxxx> wrote:
Though it is bad idea to call a system call from kernel space
is it possible any how to call a system call from kernel space?Generally a better idea to user kernel interfaces directly instead of sys calls. Further most sys call functions are not exported so you can't call them from your kernel module. You'll have to EXPORT_SYMBOL them and recompile your kernel which is kind of ugly.If you can tell us which syscalls you'd like to make, maybe we can suggest some alternatives-Joel
--
Regards,
Rahul Patil
