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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