[v3] sysvinit-inittab: support non-busybox-getty on serial consoles

Submitted by André Draszik on Feb. 11, 2019, 11:21 a.m. | Patch ID: 158647

Details

Message ID 20190211112106.4530-1-git@andred.net
State Accepted
Commit 37be77565d323fc543427ad47399996119f59ab1
Headers show

Commit Message

André Draszik Feb. 11, 2019, 11:21 a.m.
From: André Draszik <andre.draszik@jci.com>

Busybox' getty has code to try to make itself a session leader,
whereas util-linux' agetty doesn't. It expects this to happen
from outside.
When getty is not a session leader, many things don't work on
the serial console, e.g. setting the terminal process group,
job control doesn't work, etc.

Executing image tests also fails with AssertionErrors, because
    Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot get controlling tty: Operation not permitted
    Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot set process group: Inappropriate ioctl for device

Update the start_getty script to invoke getty via the setsid
utility if needed, i.e. if /sbin/getty is not busybox getty.

[YOCTO #13058]

Signed-off-by: André Draszik <andre.draszik@jci.com>

---
v3: also get rid of eval
v2: fork fewer processes
---
 .../sysvinit/sysvinit-inittab/start_getty          | 14 +++++++++++++-
 .../sysvinit/sysvinit-inittab_2.88dsf.bb           |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

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diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
index e15ae35f90..96fd6cfcfd 100644
--- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
+++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
@@ -13,6 +13,18 @@  active_serial=$(grep "serial" /proc/tty/drivers | cut -d/ -f1 | sed "s/ *$//")
 # Rephrase input parameter from ttyS target index (ttyS1, ttyS2, ttyAMA0, etc).
 runtime_tty=$(echo $2 | grep -oh '[0-9]')
 
+# busybox' getty does this itself, util-linux' agetty needs extra help
+getty="/sbin/getty"
+case $(readlink -f "${getty}") in
+    */busybox*)
+        ;;
+    *)
+        if [ -x "/usr/bin/setsid" ] ; then
+            setsid="/usr/bin/setsid"
+        fi
+        ;;
+esac
+
 # Backup $IFS.
 DEFAULT_IFS=$IFS
 # Customize Internal Field Separator.
@@ -31,7 +43,7 @@  for line in $active_serial; do
 			then
 				if [ -c /dev/$2 ]
 				then
-				    /sbin/getty -L $1 $2 $3
+				    ${setsid:-} ${getty} -L $1 $2 $3
 				fi
 				break
 			fi
diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
index 8585a418ab..bfd890d924 100644
--- a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
+++ b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
@@ -20,6 +20,7 @@  do_install() {
     install -m 0644 ${WORKDIR}/inittab ${D}${sysconfdir}/inittab
     install -d ${D}${base_bindir}
     install -m 0755 ${WORKDIR}/start_getty ${D}${base_bindir}/start_getty
+    sed -e 's,/usr/bin,${bindir},g' -i ${D}${base_bindir}/start_getty
 
     set -x
     tmp="${SERIAL_CONSOLES}"

Comments

Andre McCurdy Feb. 11, 2019, 6:11 p.m.
On Mon, Feb 11, 2019 at 3:21 AM André Draszik <git@andred.net> wrote:
> From: André Draszik <andre.draszik@jci.com>
> Busybox' getty has code to try to make itself a session leader,
> whereas util-linux' agetty doesn't. It expects this to happen
> from outside.
> When getty is not a session leader, many things don't work on
> the serial console, e.g. setting the terminal process group,
> job control doesn't work, etc.
>
> Executing image tests also fails with AssertionErrors, because
>     Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot get controlling tty: Operation not permitted
>     Feb  5 16:12:55 qemuarm getty[590]: /dev/ttyAMA1: cannot set process group: Inappropriate ioctl for device
>
> Update the start_getty script to invoke getty via the setsid
> utility if needed, i.e. if /sbin/getty is not busybox getty.
>
> [YOCTO #13058]
>
> Signed-off-by: André Draszik <andre.draszik@jci.com>
>
> ---
> v3: also get rid of eval
> v2: fork fewer processes
> ---
>  .../sysvinit/sysvinit-inittab/start_getty          | 14 +++++++++++++-
>  .../sysvinit/sysvinit-inittab_2.88dsf.bb           |  1 +
>  2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> index e15ae35f90..96fd6cfcfd 100644
> --- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> +++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
> @@ -13,6 +13,18 @@ active_serial=$(grep "serial" /proc/tty/drivers | cut -d/ -f1 | sed "s/ *$//")
>  # Rephrase input parameter from ttyS target index (ttyS1, ttyS2, ttyAMA0, etc).
>  runtime_tty=$(echo $2 | grep -oh '[0-9]')
>
> +# busybox' getty does this itself, util-linux' agetty needs extra help
> +getty="/sbin/getty"
> +case $(readlink -f "${getty}") in

Maybe directly checking the output of "getty --version" would be even
more efficient than trying to infer busybox -vs- util-linux based on
symlinks?

Checking symlinks will fail if busybox is built with
CONFIG_FEATURE_INDIVIDUAL (which we do have support for in the busybox
recipe... even if no one actually uses it).

> +    */busybox*)
> +        ;;
> +    *)
> +        if [ -x "/usr/bin/setsid" ] ; then
> +            setsid="/usr/bin/setsid"
> +        fi
> +        ;;
> +esac
> +
>  # Backup $IFS.
>  DEFAULT_IFS=$IFS
>  # Customize Internal Field Separator.
> @@ -31,7 +43,7 @@ for line in $active_serial; do
>                         then
>                                 if [ -c /dev/$2 ]
>                                 then
> -                                   /sbin/getty -L $1 $2 $3
> +                                   ${setsid:-} ${getty} -L $1 $2 $3
>                                 fi
>                                 break
>                         fi
> diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
> index 8585a418ab..bfd890d924 100644
> --- a/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
> +++ b/meta/recipes-core/sysvinit/sysvinit-inittab_2.88dsf.bb
> @@ -20,6 +20,7 @@ do_install() {
>      install -m 0644 ${WORKDIR}/inittab ${D}${sysconfdir}/inittab
>      install -d ${D}${base_bindir}
>      install -m 0755 ${WORKDIR}/start_getty ${D}${base_bindir}/start_getty
> +    sed -e 's,/usr/bin,${bindir},g' -i ${D}${base_bindir}/start_getty
>
>      set -x
>      tmp="${SERIAL_CONSOLES}"
> --
> 2.20.1
>
> --
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