FC3 module sys_print how...

From: Mukund JB.
Date: Fri Jul 15 2005 - 07:00:01 EST




Dear Linux-lovers.



I am trying to build a 2.6.10 linux kernel module to print messages to a
file. I have done this 2.4 and I was successful but I am failing here.



I am using the sys_open, sys_write calls to do so.

I am getting a compilation warning and I find no .ko file created
finally instead I find an .o.ko file.



*** WARNIG: "sys_write" [/home/cf.o.ko] undefined!

Below is the module code. Please suggest me what could be the problem:-





#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <asm/fcntl.h> /* for O_WRONLY */

#include <linux/syscalls.h> /* for sys_ functions */

#include <asm/uaccess.h> /* for set_fs(), get_fs() etc. */

#include <linux/string.h> /* for string length */

#include <linux/slab.h> /* for kmalloc */



MODULE_LICENSE("GPL");

/*

#define DBG

#define PRINTK(fmt,arg...) printk("DBG INFO <%s> | "
fmt,__FUNCTION__,##arg)

#else

#define PRINTK(fmt,arg...) while(0)

#endif

*/



typedef struct tagWRITE_TEST

{

unsigned long fd;

unsigned long x;



}WRITE_TEST, *PWRITE_TEST;



PWRITE_TEST ptest;



void SysPrint(char * pString, ...)

{

static char buff[1024];

va_list ap;



va_start(ap,pString);

vsprintf((char *)buff, pString, ap);

va_end(ap);



sys_write(ptest->fd,(char *)buff,(size_t)strlen(buff));

}



int init_module(void)

{



printk("<%s> invoked!\n",__FUNCTION__);

printk("File Creation Testing in Kernel Module!\n");



set_fs(get_ds());



/* allocate the memory for structre */

ptest = (PWRITE_TEST)kmalloc(sizeof(WRITE_TEST),GFP_KERNEL);

if(ptest == NULL)

{

printk("Structure Memory Allocation Fails!\n");

return -ENOMEM;

}



ptest->fd = sys_open("srcdebug.txt", O_CREAT | O_WRONLY, 644);

if (ptest->fd == 0)

{

SysPrint("File Creation Error!!!\n");

return 1;

}



SysPrint("File Creation Testing in Kernel Module!\n");

SysPrint("Srinivas Testing the File Creation\n");

sys_close(ptest->fd);



return 0;

}



void cleanup_module(void)

{

printk("Good bye!\n");



/* free the allocated memory */

kfree(ptest);

}



Regards,

Mukund jampala




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