Messages in this thread | | | Date | Thu, 7 Apr 2005 11:59:04 -0700 | From | "Randy.Dunlap" <> | Subject | Re: Linux-2.6.11 can't disable CAD |
| |
On Thu, 7 Apr 2005 11:16:14 -0400 (EDT) Richard B. Johnson wrote:
| | In the not-too distant past, one could disable Ctl-Alt-DEL. | Can't do it anymore.
What should disabling C_A_D do?
| Script started on Thu 07 Apr 2005 10:58:11 AM EDT | [SNIPPED leading stuff...] | | mprotect(0xb7fe4000, 28672, PROT_READ|PROT_EXEC) = 0 | brk(0) = 0x804a000 | brk(0x8053000) = 0x8053000 | reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, LINUX_REBOOT_CMD_CAD_OFF) = 0 | pause( <unfinished ...> | _exit(0) = ? | # exit | Script done on Thu 07 Apr 2005 10:58:21 AM EDT
What program is that? I'm just echoing 0 | 1 into /proc/sys/kernel/ctrl-alt-del , is that equivalent? or have you tried that?
| Observe that reboot() returns 0 and `strace` understands what | parameters were passed. The result is that, if I hit Ctl-Alt-Del, | `init` will still execute the shutdown-order (INIT 0).
echo 0 > /proc/sys/kernel/ctrl-alt-del is same as CAD_OFF echo 1 is same as CAD_ON
I tested 2.4.28, 2.6.3, 2.6.9, 2.6.11, and all of them behaved the same way for me. If it's an issue with using a syscall to change the setting, I'll be glad to look into that too.
observed behaviors: CAD enabled + C_A_D keys => call machine_reboot() to reboot quickly, no normal shutdown sequence; CAD disabled + C_A_D keys => kill init, go thru normal clean shutdown sequence; are these the expected behaviors?
| A side note, while researching this problem, I think I found | that LINUX_REBOOT_MAGIC2 is Linus' birthday (in hex). Maybe | the problem is that he no longer observes his birthday?
--- ~Randy - 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/
| |