[Buildroot] [PATCH 0/3] Alternative way to wait interfaces on bootup

[Buildroot] [PATCH 0/3] Alternative way to wait interfaces on bootup

[Jérôme Pouiller]

As discussed here:

   http://lists.busybox.net/pipermail/buildroot/2015-October/142329.html

J?r?me Pouiller (3):
  Revert "package/initscripts: S40network: wait for network interfaces
    to appear"
  skeleton: optionally wait for network interfaces to appear
  skeleton: wait interface to appear if dhcp is enabled

 package/initscripts/init.d/S40network              | 29 ----------------------
 package/skeleton/skeleton.mk                       |  1 +
 system/skeleton/etc/network/if-pre-up.d/wait_iface | 28 +++++++++++++++++++++
 3 files changed, 29 insertions(+), 29 deletions(-)
 create mode 100755 system/skeleton/etc/network/if-pre-up.d/wait_iface

-- 
2.1.4

[Buildroot] [PATCH 1/3] Revert "package/initscripts: S40network: wait for network interfaces to appear"

[Jérôme Pouiller]

This reverts commit 49964858f45d2243c513e6d362e992ad89ec7a45. It is
going to be replaced with an ifup hook in next patch.

Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
---
 package/initscripts/init.d/S40network | 29 -----------------------------
 1 file changed, 29 deletions(-)

diff --git a/package/initscripts/init.d/S40network b/package/initscripts/init.d/S40network
index a8d7c5d..7b11d8b 100755
--- a/package/initscripts/init.d/S40network
+++ b/package/initscripts/init.d/S40network
@@ -6,37 +6,8 @@
 # Debian ifupdown needs the /run/network lock directory
 mkdir -p /run/network
 
-# In case we have a slow-to-appear interface (e.g. eth-over-USB),
-# and we need to configure it, wait until it appears, but not too
-# long either. WAIT_DELAY is in seconds.
-WAIT_DELAY=15
-
-wait_for_interfaces() {
-	IFACES=$(awk '/^auto/ { print $2 }' /etc/network/interfaces)
-	[ -n "$IFACES" ] || return
-
-	printf "Waiting for network interfaces to appear"
-
-	for i in $(seq $WAIT_DELAY); do
-	    for IFACE in $IFACES; do
-		if [ ! -e "/sys/class/net/$IFACE" ]; then
-		    printf "."
-		    sleep 1
-		    continue 2
-		fi
-	    done
-
-	    printf " ok\n"; return
-	done
-
-	printf " timeout\n"
-	exit 1
-}
-
 case "$1" in
   start)
-	wait_for_interfaces
-
  	echo "Starting network..."
 	/sbin/ifup -a
 	;;
-- 
2.1.4

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Jérôme Pouiller]

This patch has same purpose than 49964858f45d2243c513e6d362e992ad89ec7a45:

  On some machines, the network interface is slow to appear. For example,
  on the Raspberry Pi, the network interface eth0 is an ethernet-over-USB,
  and our standard boot process is too fast, so our network startup script
  is called before the USB bus is compeltely enumerated, thus it can't
  configure eth0.

  Closes #8116.

However, it use an optionnal ifupdown hook instead of an initscript.

Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
---
 system/skeleton/etc/network/if-pre-up.d/wait_iface | 28 ++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100755 system/skeleton/etc/network/if-pre-up.d/wait_iface

diff --git a/system/skeleton/etc/network/if-pre-up.d/wait_iface b/system/skeleton/etc/network/if-pre-up.d/wait_iface
new file mode 100755
index 0000000..4f0866b
--- /dev/null
+++ b/system/skeleton/etc/network/if-pre-up.d/wait_iface
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# In case we have a slow-to-appear interface (e.g. eth-over-USB),
+# and we need to configure it, wait until it appears, but not too
+# long either. IF_WAIT_DELAY is in seconds.
+
+if [ "${IF_WAIT_DELAY}" ]; then
+
+    printf "Waiting for interface %s to appear" "${IFACE}"
+    while [ ${IF_WAIT_DELAY} -gt 0 ]; do
+
+        if [ -e "/sys/class/net/${IFACE}" ]; then
+
+            printf " yes\n"
+            exit 0
+
+        fi
+        sleep 1
+        printf "."
+
+        : $((IF_WAIT_DELAY -= 1))
+
+    done
+    printf " no.\n"
+    exit 1
+
+fi
+
-- 
2.1.4

[Buildroot] [PATCH 3/3] skeleton: wait interface to appear if dhcp is enabled

[Jérôme Pouiller]

wait-delay hook is enabled only if wait-delay property appears in
/etc/network/interfaces. This patch enable it automaticaly when
interface is configured through DHCP at bootup. However, if user choose
to write /etc/network/interface himself, he have to explicitly
set wait-delay.

Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
---
 package/skeleton/skeleton.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/skeleton/skeleton.mk b/package/skeleton/skeleton.mk
index 920d3b4..d1b797d 100644
--- a/package/skeleton/skeleton.mk
+++ b/package/skeleton/skeleton.mk
@@ -89,6 +89,7 @@ define SET_NETWORK_DHCP
 		echo ;                                               \
 		echo "auto $(NETWORK_DHCP_IFACE)";                   \
 		echo "iface $(NETWORK_DHCP_IFACE) inet dhcp";        \
+		echo "	wait-delay 15";                              \
 	) >> $(TARGET_DIR)/etc/network/interfaces
 endef
 endif
-- 
2.1.4

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Yann E. MORIN]

J?r?me, All,

On 2015-10-28 16:59 +0100, J?r?me Pouiller spake thusly:
> This patch has same purpose than 49964858f45d2243c513e6d362e992ad89ec7a45:
> 
>   On some machines, the network interface is slow to appear. For example,
>   on the Raspberry Pi, the network interface eth0 is an ethernet-over-USB,
>   and our standard boot process is too fast, so our network startup script
>   is called before the USB bus is compeltely enumerated, thus it can't
>   configure eth0.
> 
>   Closes #8116.
> 
> However, it use an optionnal ifupdown hook instead of an initscript.
> 
> Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
> ---
>  system/skeleton/etc/network/if-pre-up.d/wait_iface | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100755 system/skeleton/etc/network/if-pre-up.d/wait_iface
> 
> diff --git a/system/skeleton/etc/network/if-pre-up.d/wait_iface b/system/skeleton/etc/network/if-pre-up.d/wait_iface
> new file mode 100755
> index 0000000..4f0866b
> --- /dev/null
> +++ b/system/skeleton/etc/network/if-pre-up.d/wait_iface
> @@ -0,0 +1,28 @@
> +#!/bin/sh
> +
> +# In case we have a slow-to-appear interface (e.g. eth-over-USB),
> +# and we need to configure it, wait until it appears, but not too
> +# long either. IF_WAIT_DELAY is in seconds.
> +
> +if [ "${IF_WAIT_DELAY}" ]; then
> +

Please drop the empty lines.

Also, I would have preferred patches 2 & 3 to be folded into a single
patch. I don't really understand how it all works:

  - does the busybox ifup-down and full-fledged ifup-down support
    wait-delay?
  - I looked at man 5 interfaces, and there is no mention of wait-delay,
  - I don't see how 'wait-delay' translates to 'wait_iface'
  - I guess 'wait-delay' is made an environment variable IF_WAIT_DELAY
    before the script is run, but I'd have preferred explanations rather
    than having to guess.

Care to shed some light, please?

Otherwise, the idea looks fine to me. Thanks! :-)

Regards,
Yann E. MORIN.

> +    printf "Waiting for interface %s to appear" "${IFACE}"
> +    while [ ${IF_WAIT_DELAY} -gt 0 ]; do
> +
> +        if [ -e "/sys/class/net/${IFACE}" ]; then
> +
> +            printf " yes\n"
> +            exit 0
> +
> +        fi
> +        sleep 1
> +        printf "."
> +
> +        : $((IF_WAIT_DELAY -= 1))
> +
> +    done
> +    printf " no.\n"
> +    exit 1
> +
> +fi
> +
> -- 
> 2.1.4
> 

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Jérôme Pouiller]

Hello Yann,

On Wednesday 28 October 2015 18:46:53 Yann E. MORIN wrote:
> J?r?me, All,
> 
> On 2015-10-28 16:59 +0100, J?r?me Pouiller spake thusly:
[...]
> Please drop the empty lines.
There were empty lines in original patch ;-).

> Also, I would have preferred patches 2 & 3 to be folded into a single
> patch. 
ok.

> I don't really understand how it all works:
> 
>   - does the busybox ifup-down and full-fledged ifup-down support
>     wait-delay?
Yes, both.

>   - I looked at man 5 interfaces, and there is no mention of
> wait-delay,

I have found documentation related to if-*.d scripts in section called 
"IFACE OPTIONS" of interfaces(5) of my debian.


>   - I don't see how 'wait-delay' translates to 'wait_iface'

From interfaces(5):

  "Additionally, all options given in an interface definition stanza are 
exported to the environment in upper case  with  "IF_"  prepended  and  
with hyphens converted to underscores and non-alphanumeric characters 
discarded."


>   - I guess 'wait-delay' is made an environment variable IF_WAIT_DELAY
> before the script is run, but I'd have preferred explanations rather
> than having to guess.
> 
> Care to shed some light, please?

Regards,

-- 
J?r?me Pouiller, Sysmic
Embedded Linux specialist
http://www.sysmic.fr

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Yann E. MORIN]

J?r?me, All,

On 2015-10-28 21:21 +0100, J?r?me Pouiller spake thusly:
> On Wednesday 28 October 2015 18:46:53 Yann E. MORIN wrote:
> > On 2015-10-28 16:59 +0100, J?r?me Pouiller spake thusly:
> [...]
> > Please drop the empty lines.
> There were empty lines in original patch ;-).

OK, I see. ;-)

Still, please drop them next time, please.

[--SNIP--]
> >   - I looked at man 5 interfaces, and there is no mention of
> > wait-delay,
> 
> I have found documentation related to if-*.d scripts in section called 
> "IFACE OPTIONS" of interfaces(5) of my debian.
> 
> >   - I don't see how 'wait-delay' translates to 'wait_iface'
> 
> From interfaces(5):
> 
>   "Additionally, all options given in an interface definition stanza are 
> exported to the environment in upper case  with  "IF_"  prepended  and  
> with hyphens converted to underscores and non-alphanumeric characters 
> discarded."

OK, thanks for the explanations. So there is no relation between the
'stanza' name and the script name, right?

Also, I read this in man 5 interfaces;

    When ifupdown is being called with the --all option, before doing
    anything to interfaces, if [sic] calls all the hook scripts (pre-up
    or down) with IFACE set to "--all", LOGICAL set to the current value
    of --allow parameter (or "auto" if it's  not set), ADDRFAM="meta"
    and METHOD="none". After all the interfaces have been brought up or
    taken down, the appropriate scripts (up or post-down) are executed.

Since S40network calls 'ifup -a' and you added a pre-up script, I guess
it should filter out the '--all' interface and exit early in that case.

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Peter Korsgaard]

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

Hi,

 > Also, I read this in man 5 interfaces;

 >     When ifupdown is being called with the --all option, before doing
 >     anything to interfaces, if [sic] calls all the hook scripts (pre-up
 >     or down) with IFACE set to "--all", LOGICAL set to the current value
 >     of --allow parameter (or "auto" if it's  not set), ADDRFAM="meta"
 >     and METHOD="none". After all the interfaces have been brought up or
 >     taken down, the appropriate scripts (up or post-down) are executed.

 > Since S40network calls 'ifup -a' and you added a pre-up script, I guess
 > it should filter out the '--all' interface and exit early in that case.

As far as I can see from the busybox implementation atleast, -a (all)
only causes it to run ifup/ifdown (with IFACE set to the interface name) for
each interface listed as auto, so it doesn't do the "--all" thing, but
the Debian variant does.

-- 
Venlig hilsen,
Peter Korsgaard 

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Yann E. MORIN]

Peter, All,

On 2015-10-28 22:51 +0100, Peter Korsgaard spake thusly:
> >>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:
>  > Also, I read this in man 5 interfaces;
> 
>  >     When ifupdown is being called with the --all option, before doing
>  >     anything to interfaces, if [sic] calls all the hook scripts (pre-up
>  >     or down) with IFACE set to "--all", LOGICAL set to the current value
>  >     of --allow parameter (or "auto" if it's  not set), ADDRFAM="meta"
>  >     and METHOD="none". After all the interfaces have been brought up or
>  >     taken down, the appropriate scripts (up or post-down) are executed.
> 
>  > Since S40network calls 'ifup -a' and you added a pre-up script, I guess
>  > it should filter out the '--all' interface and exit early in that case.
> 
> As far as I can see from the busybox implementation atleast, -a (all)
> only causes it to run ifup/ifdown (with IFACE set to the interface name) for
> each interface listed as auto, so it doesn't do the "--all" thing, but
> the Debian variant does.

Since we already have the option to use the full-fledged ifup-down, we
should support the case where IFACE=--all in the script.

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Peter Korsgaard]

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

Hi,

>> As far as I can see from the busybox implementation atleast, -a (all)
 >> only causes it to run ifup/ifdown (with IFACE set to the interface name) for
 >> each interface listed as auto, so it doesn't do the "--all" thing, but
 >> the Debian variant does.

 > Since we already have the option to use the full-fledged ifup-down, we
 > should support the case where IFACE=--all in the script.

Yes, agreed - My comment was for information only.

-- 
Venlig hilsen,
Peter Korsgaard 

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Nicolas Cavallari]

On 28/10/2015 22:37, Yann E. MORIN wrote:
> OK, thanks for the explanations. So there is no relation between the
> 'stanza' name and the script name, right?

None at all. ifupdown just run-parts /etc/if-$PHASE.d/ and the scripts
are responsible for not doing anything when they shouldn't.

> Also, I read this in man 5 interfaces;
> 
>     When ifupdown is being called with the --all option, before doing
>     anything to interfaces, if [sic] calls all the hook scripts (pre-up
>     or down) with IFACE set to "--all", LOGICAL set to the current value
>     of --allow parameter (or "auto" if it's  not set), ADDRFAM="meta"
>     and METHOD="none". After all the interfaces have been brought up or
>     taken down, the appropriate scripts (up or post-down) are executed.
> 
> Since S40network calls 'ifup -a' and you added a pre-up script, I guess
> it should filter out the '--all' interface and exit early in that case.

When run in this case, it will have no IF_WAIT_DELAY variable, so the
script will not do anything.

[Buildroot] [PATCH 2/3] skeleton: optionally wait for network interfaces to appear

[Nicolas Cavallari]

On 28/10/2015 16:59, J?r?me Pouiller wrote:
> This patch has same purpose than 49964858f45d2243c513e6d362e992ad89ec7a45:
> 
>   On some machines, the network interface is slow to appear. For example,
>   on the Raspberry Pi, the network interface eth0 is an ethernet-over-USB,
>   and our standard boot process is too fast, so our network startup script
>   is called before the USB bus is compeltely enumerated, thus it can't
>   configure eth0.
> 
>   Closes #8116.
> 
> However, it use an optionnal ifupdown hook instead of an initscript.
> 
> Signed-off-by: J?r?me Pouiller <jezz@sysmic.org>
> ---
>  system/skeleton/etc/network/if-pre-up.d/wait_iface | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100755 system/skeleton/etc/network/if-pre-up.d/wait_iface
> 
> diff --git a/system/skeleton/etc/network/if-pre-up.d/wait_iface b/system/skeleton/etc/network/if-pre-up.d/wait_iface
> new file mode 100755
> index 0000000..4f0866b
> --- /dev/null
> +++ b/system/skeleton/etc/network/if-pre-up.d/wait_iface
> @@ -0,0 +1,28 @@
> +#!/bin/sh
> +
> +# In case we have a slow-to-appear interface (e.g. eth-over-USB),
> +# and we need to configure it, wait until it appears, but not too
> +# long either. IF_WAIT_DELAY is in seconds.
> +
> +if [ "${IF_WAIT_DELAY}" ]; then
> +
> +    printf "Waiting for interface %s to appear" "${IFACE}"

I think we shouldn't print this scary message when the interface already
exist in the first place... I was suggesting to only do it if
VERBOSITY=1 but busybox does not support that.

> +    while [ ${IF_WAIT_DELAY} -gt 0 ]; do
> +
> +        if [ -e "/sys/class/net/${IFACE}" ]; then
> +
> +            printf " yes\n"

So this prints:
"Waiting for interface dummy0 to appear..... yes"
or
"Waiting for interface dummy0 to appear............... no"

We should maybe just print a new line on success and an explicit error
message on failure.

> +            exit 0
> +
> +        fi
> +        sleep 1
> +        printf "."
> +
> +        : $((IF_WAIT_DELAY -= 1))
> +
> +    done
> +    printf " no.\n"
> +    exit 1
> +
> +fi
> +
>