Messages in this thread |  | | | Date | Wed, 4 May 2005 17:20:36 +0200 (CEST) | | From | Leszek Koltunski <> | | Subject | Cannot read from /dev/kmem |
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Kernel 2.6.11 , I cannot seem to be able to read from /dev/kmem... The following little proggie
#include <stdio.h> #include <fcntl.h> #include <errno.h>
struct { unsigned short limit; unsigned int base; } __attribute__ ((packed)) idtr; struct { unsigned short off1; unsigned short sel; unsigned char none,flags; unsigned short off2; } __attribute__ ((packed)) idt; int main() { int result, kmem = open ("/dev/kmem",O_RDONLY); asm ("sidt %0" : "=m" (idtr)); printf("idtr base at 0x%X\n",(int)idtr.base);
if (kmem<0) return 1; if (lseek(kmem, idtr.base + 8*0x80,SEEK_SET) != idtr.base + 8*0x80 ) { perror("kmem lseek"); exit(1); } result = read(kmem, &idt , sizeof(idt) );
if( result != sizeof(idt) ) { printf("result: %d, sizeof(idt)= %d errno=%d\n", result, sizeof(idt), errno); } close(kmem);
return 0; }
returns
utumno:/home/leszek/progs/module/hijack# ./test idtr base at 0xC0423000 result: -1, sizeof(idt)= 8 errno=22
??? EINVAL
I remember this working on a 2.4.x kernel.... Leszek Koltunski - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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