Li,
Regarding your commit 923c7538236564c46ee80c253a416705321f13e3 , I
plan to apply the following patch to the reboot(2) manual page. Does
it look okay to you?
Thanks,
Michael
diff --git a/man2/reboot.2 b/man2/reboot.2
index 8347870..1c17b85 100644
--- a/man2/reboot.2
+++ b/man2/reboot.2
@@ -24,7 +24,7 @@
.\" Modified, 27 May 2004, Michael Kerrisk <[email protected]>
.\" Added notes on capability requirements
.\"
-.TH REBOOT 2 2010-10-31 "Linux" "Linux Programmer's Manual"
+.TH REBOOT 2 2013-03-12 "Linux" "Linux Programmer's Manual"
.SH NAME
reboot \- reboot or enable/disable Ctrl-Alt-Del
.SH SYNOPSIS
@@ -147,6 +147,26 @@ For the i386 architecture, the additional
argument does not do
anything at present (2.1.122), but the type of reboot can be
determined by kernel command-line arguments ("reboot=...") to be
either warm or cold, and either hard or through the BIOS.
+.SS Behavior inside PID namespaces
+.\" commit commit 923c7538236564c46ee80c253a416705321f13e3
+Since Linux 3.9, when
+.BR reboot ()
+is called from a PID namespace (see
+.BR pid_namespaces (7))
+other than the initial PID namespace,
+the effect of the call is to send a signal to the namespace "init" process.
+.BR LINUX_REBOOT_CMD_RESTART
+and
+.BR LINUX_REBOOT_CMD_RESTART2
+cause a
+.BR SIGHUP
+signal to be sent.
+.BR LINUX_REBOOT_CMD_POWER_OFF
+and
+.BR LINUX_REBOOT_CMD_HALT
+cause a
+.B SIGINT
+signal to be sent.
.SH RETURN VALUE
For the values of
.I cmd
"Michael Kerrisk (man-pages)" <[email protected]> writes:
> Li,
>
> Regarding your commit 923c7538236564c46ee80c253a416705321f13e3 , I
> plan to apply the following patch to the reboot(2) manual page. Does
> it look okay to you?
You have documented the behavior as of 3.4.
The change in 3.9 is to allow that same behavior in a pid_namespace
created with a user namespace. Aka in 3.9 the permission
check changed from capable(CAP_SYS_BOOT) to ns_capable(pid_ns->user_ns, CAP_SYS_BOOT);
Eric
> Thanks,
>
> Michael
>
> diff --git a/man2/reboot.2 b/man2/reboot.2
> index 8347870..1c17b85 100644
> --- a/man2/reboot.2
> +++ b/man2/reboot.2
> @@ -24,7 +24,7 @@
> .\" Modified, 27 May 2004, Michael Kerrisk <[email protected]>
> .\" Added notes on capability requirements
> .\"
> -.TH REBOOT 2 2010-10-31 "Linux" "Linux Programmer's Manual"
> +.TH REBOOT 2 2013-03-12 "Linux" "Linux Programmer's Manual"
> .SH NAME
> reboot \- reboot or enable/disable Ctrl-Alt-Del
> .SH SYNOPSIS
> @@ -147,6 +147,26 @@ For the i386 architecture, the additional
> argument does not do
> anything at present (2.1.122), but the type of reboot can be
> determined by kernel command-line arguments ("reboot=...") to be
> either warm or cold, and either hard or through the BIOS.
> +.SS Behavior inside PID namespaces
> +.\" commit commit 923c7538236564c46ee80c253a416705321f13e3
> +Since Linux 3.9, when
^^^ 3.4
> +.BR reboot ()
> +is called from a PID namespace (see
> +.BR pid_namespaces (7))
> +other than the initial PID namespace,
> +the effect of the call is to send a signal to the namespace "init" process.
> +.BR LINUX_REBOOT_CMD_RESTART
> +and
> +.BR LINUX_REBOOT_CMD_RESTART2
> +cause a
> +.BR SIGHUP
> +signal to be sent.
> +.BR LINUX_REBOOT_CMD_POWER_OFF
> +and
> +.BR LINUX_REBOOT_CMD_HALT
> +cause a
> +.B SIGINT
> +signal to be sent.
> .SH RETURN VALUE
> For the values of
> .I cmd
On Tue, Mar 12, 2013 at 8:20 AM, Eric W. Biederman
<[email protected]> wrote:
> "Michael Kerrisk (man-pages)" <[email protected]> writes:
>
>> Li,
>>
>> Regarding your commit 923c7538236564c46ee80c253a416705321f13e3 , I
>> plan to apply the following patch to the reboot(2) manual page. Does
>> it look okay to you?
>
> You have documented the behavior as of 3.4.
Thanks Eric. I tweaked the version number.
> The change in 3.9 is to allow that same behavior in a pid_namespace
> created with a user namespace. Aka in 3.9 the permission
> check changed from capable(CAP_SYS_BOOT) to ns_capable(pid_ns->user_ns, CAP_SYS_BOOT);
Does anything need to be detailed about this in the man page then?
Thanks,
Michael
>
> Eric
>
>> Thanks,
>>
>> Michael
>>
>> diff --git a/man2/reboot.2 b/man2/reboot.2
>> index 8347870..1c17b85 100644
>> --- a/man2/reboot.2
>> +++ b/man2/reboot.2
>> @@ -24,7 +24,7 @@
>> .\" Modified, 27 May 2004, Michael Kerrisk <[email protected]>
>> .\" Added notes on capability requirements
>> .\"
>> -.TH REBOOT 2 2010-10-31 "Linux" "Linux Programmer's Manual"
>> +.TH REBOOT 2 2013-03-12 "Linux" "Linux Programmer's Manual"
>> .SH NAME
>> reboot \- reboot or enable/disable Ctrl-Alt-Del
>> .SH SYNOPSIS
>> @@ -147,6 +147,26 @@ For the i386 architecture, the additional
>> argument does not do
>> anything at present (2.1.122), but the type of reboot can be
>> determined by kernel command-line arguments ("reboot=...") to be
>> either warm or cold, and either hard or through the BIOS.
>> +.SS Behavior inside PID namespaces
>> +.\" commit commit 923c7538236564c46ee80c253a416705321f13e3
>> +Since Linux 3.9, when
> ^^^ 3.4
>> +.BR reboot ()
>> +is called from a PID namespace (see
>> +.BR pid_namespaces (7))
>> +other than the initial PID namespace,
>> +the effect of the call is to send a signal to the namespace "init" process.
>> +.BR LINUX_REBOOT_CMD_RESTART
>> +and
>> +.BR LINUX_REBOOT_CMD_RESTART2
>> +cause a
>> +.BR SIGHUP
>> +signal to be sent.
>> +.BR LINUX_REBOOT_CMD_POWER_OFF
>> +and
>> +.BR LINUX_REBOOT_CMD_HALT
>> +cause a
>> +.B SIGINT
>> +signal to be sent.
>> .SH RETURN VALUE
>> For the values of
>> .I cmd
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/