Re: [sysvinit-devel] [PATCH] automatically spawn agetty on kernel consoles

On Thu, May 26, 2011 at 08:23:30AM +0200, Ludwig Nussel wrote:
> The feature is useful for developers and admins that occasionally need
> to boot with e.g. console=ttyS0.
> The built in default can be overridden via inittab for each device. An
> entry like "S0::off:" turns off the getty on ttyS0.
> ---
>  src/init.c |   74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 74 insertions(+), 0 deletions(-)

Ludwig?

Please check out the code of src/consoles.c and src/consoles.h
which does a similar job by not only using "/proc/cmdline" but
also "/proc/consoles" or "/sys/class/tty" if available.

Nonetheless a configure option as mentioned by Mike should be also
added.

   Werner

> diff --git a/src/init.c b/src/init.c
> index d379fb2..13deef7 100644
> --- a/src/init.c
> +++ b/src/init.c
>  <at>  <at>  -1243,6 +1243,76  <at>  <at>  void startup(CHILD *ch)
>  	}
>  }
>  
> +#ifdef __linux__
> +static
> +void check_kernel_console()
> +{
> +	FILE* fp;
> +	char buf[4096];
> +	if ((fp = fopen("/proc/cmdline", "r")) == 0) {
> +		return;
> +	}
> +	if (fgets(buf, sizeof(buf), fp)) {
> +		char* p = buf;
> +		while ((p = strstr(p, "console="))) {
> +			char* e;
> +			p += strlen("console=");
> +			for (e = p; *e; ++e) {
> +				switch (*e) {
> +					case '-' ... '9':
> +					case 'A' ... 'Z':
> +					case '_':
> +					case 'a' ... 'z':
> +						continue;
> +				}
> +				break;
> +			}
> +			if (p != e) {
> +				CHILD* old;
> +				int dup = 0;
> +				char id[8] = {0};
> +				char dev[32] = {0};
> +				strncpy(dev, p, MIN(sizeof(dev), (unsigned)(e-p)));
> +				if (!strncmp(dev, "tty", 3))
> +					strncpy(id, dev+3, sizeof(id));
> +				else
> +					strncpy(id, dev, sizeof(id));
> +
> +				for(old = newFamily; old; old = old->next) {
> +					if (!strcmp(old->id, id)) {
> +						dup = 1;
> +					}
> +				}
> +				if (!dup) {
> +					CHILD* ch = imalloc(sizeof(CHILD));
> +					ch->action = RESPAWN;
> +					strcpy(ch->id, id);
> +					strcpy(ch->rlevel, "2345");
> +					sprintf(ch->process, "/sbin/agetty -L -s 115200,38400,9600 %s vt102", dev);
> +					ch->next = NULL;
> +					for(old = family; old; old = old->next) {
> +						if (strcmp(old->id, ch->id) == 0) {
> +							old->new = ch;
> +							break;
> +						}
> +					}
> +					/* add to end */
> +					for(old = newFamily; old; old = old->next) {
> +						if (!old->next) {
> +							old->next = ch;
> +							break;
> +						}
> +					}
> +
> +					initlog(L_VB, "added agetty on %s with id %s", dev, id);
> +				}
> +			}
> +		}
> +	}
> +	fclose(fp);
> +	return;
> +}
> +#endif
>  
>  /*
>   *	Read the inittab file.
>  <at>  <at>  -1455,6 +1525,10  <at>  <at>  void read_inittab(void)
>     */
>    if (fp) fclose(fp);
>  
> +#ifdef __linux__
> +  check_kernel_console();
> +#endif
> +
>    /*
>     *	Loop through the list of children, and see if they need to
>     *	be killed. 
> -- 
> 1.7.3.4
> 

--

-- 
 Dr. Werner Fink -- Software Engineer Consultant
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 phone: +49-911-740-53-0,  fax: +49-911-3206727,  www.opensuse.org
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