Messages in this thread |  | | | Date | Tue, 20 Jun 2006 06:28:02 +0200 | | From | Willy Tarreau <> | | Subject | Re: emergency or init=/bin/sh mode and terminal signals |
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On Tue, Jun 20, 2006 at 10:02:23AM +1000, David Luyer wrote: > On 20/6/06 8:09 AM, "Samuel Thibault" <samuel.thibault@ens-lyon.org> wrote: > > linux-os (Dick Johnson), le Mon 19 Jun 2006 07:37:02 -0400, a écrit : > >> You can't allow some terminal input to affect init. It has been the > >> de facto standard in Unix, that the only time one should have a > >> controlling terminal is after somebody logs in and owns something to > >> control. > > > > Ok. The following still makes sense, doesn't it? (i.e. set a session for > > the emergency shell) > > > > --- linux-2.6.17-orig/init/main.c 2006-06-18 19:22:40.000000000 +0200 > > +++ linux-2.6.17-perso/init/main.c 2006-06-20 00:07:07.000000000 +0200 > > @@ -729,6 +729,11 @@ > > run_init_process("/sbin/init"); > > run_init_process("/etc/init"); > > run_init_process("/bin/init"); > > + > > + /* Set a session for the shell. */ > > + sys_setsid(); > > + sys_ioctl(0, TIOCSCTTY, 1); > > + > > run_init_process("/bin/sh"); > > > > panic("No init found. Try passing init= option to kernel."); > > What if people are booting via /bin/sh and then setting up > their custom chroot's and init(s), and don't want these init(s) to > be part of a session? > > It is also particularly possible for an embedded system to start > up via /bin/sh running /etc/profile rather than using an init type > program. > > Also, the above doesn't help people specifying "init=/bin/sh" on the > command line (as per the original post subject). The real solution > is for them to specify a different init= or run/exec something to set > up their tty and session once logged in.
Then, I think that a solution which would fit everyone's needs would be to add a command line parameter (eg: "setsid=1") which will allow the two lines to be executed whatever the init or shell. This way, you want a session ? -> "init=/bin/sh setsid=1".
Not particularly difficult to use and does not risk to break existing setups.
> David.
Cheers, Willy
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