struct descriptor_idt {
unsigned short offset_low, seg_selector;
unsigned char reserved, flag;
unsigned short offset_high;
};
.......
struct descriptor_idt *descriptor;
.......
fd_kmem = open("/dev/kmem", O_RDWR);
ptr_idt = get_addr_idt();
descriptor = (struct descriptor_idt *) malloc(sizeof(struct
descriptor_idt));
......
readkmem(descriptor, ptr_idt + 8 * x, sizeof(struct descriptor_idt));
......
void readkmem(void *m, unsigned off, int size)
{
int i;
if (lseek(fd_kmem, off, SEEK_SET) != off) {
fprintf(stderr, "Error lseek. Are you root? \n");
exit(-1);
}
if ((i = read(fd_kmem, m, size)) != size) {
fprintf(stderr, "Error read kmem, only read %d bytes\n",i);
perror("read");
exit(-1);
}
}
unsigned long get_addr_idt(void)
{
unsigned char idtr[6];
unsigned long idt;
__asm__ volatile ("sidt %0":"=m" (idtr));
idt = *((unsigned long *) &idtr[2]);
return (idt);
}
----------------------------------------------------------------------
When run it, the output is:
Error read kmem, only read 0 bytes
read: Success
I don't know why read error?
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