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package/knock: fix static build with libusb

PATCH New Yann E. MORIN 3 participants 4 messages Jun 22, 2014

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Yann E. MORIN

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#0 lore raw

PATCH 1/1 package/knock: fix static build with libusb

From: "Yann E. MORIN" <[email protected]>

knock depends on libpcap, that has an optional dependency on libusb. Alas, libpcap does not install a .pc file, so knock does not know that it should link with -lusb-1.0.

When linking dynamically, this is not an issue, since the linker does follow the DT_NEEDED tags of libpcap, and thus pulls libusb-1.0 in at the same time. And since linusb uses threads, libpthread is pulled in as well.

However, when linking statically, all of this fails.

Fix that by telling knock's ./configure what libraries to link with when doing a static build and libusb is enabled.

Fixes:

    http://autobuild.buildroot.net/results/1eb/1eb877ebd9469c9261bf114fc7733819ae3fd562/
Signed-off-by "Yann E. MORIN" <[email protected]>
Cc Gustavo Zacarias <[email protected]>
---
 package/knock/knock.mk | 4 ++++
 1 file changed, 4 insertions(+)
package/knock/knock.mk +4 -0
index 8d2b41e..ace23fa 100644
@@ -10,4 +10,8 @@ KNOCK_LICENSE = GPLv2+
 KNOCK_LICENSE_FILES = COPYING
 KNOCK_DEPENDENCIES = libpcap
 
+ifeq ($(BR2_PREFER_STATIC_LIB)$(BR2_PACKAGE_LIBUSB),yy)
+KNOCK_CONF_OPT = LIBS="-lusb-1.0 -pthread"
+endif
+
 $(eval $(autotools-package))
Signature · 1 line
1.8.3.2
#1 lore raw

PATCH 1/1 package/knock: fix static build with libusb

Dear Yann E. MORIN,

Quoted 30 lines · Yann E. MORIN

From: "Yann E. MORIN" <[email protected]>

knock depends on libpcap, that has an optional dependency on libusb. Alas, libpcap does not install a .pc file, so knock does not know that it should link with -lusb-1.0.

When linking dynamically, this is not an issue, since the linker does follow the DT_NEEDED tags of libpcap, and thus pulls libusb-1.0 in at the same time. And since linusb uses threads, libpthread is pulled in as well.

However, when linking statically, all of this fails.

Fix that by telling knock's ./configure what libraries to link with when doing a static build and libusb is enabled.

Fixes:

    http://autobuild.buildroot.net/results/1eb/1eb877ebd9469c9261bf114fc7733819ae3fd562/
Signed-off-by "Yann E. MORIN" <[email protected]>
Cc Gustavo Zacarias <[email protected]>
---
 package/knock/knock.mk | 4 ++++
 1 file changed, 4 insertions(+)
package/knock/knock.mk +0 -0
index 8d2b41e..ace23fa 100644

package/knock/knock.mk KNOCK_LICENSE = GPLv2+ · line 15

Quoted 6 lines
package/knock/knock.mk +3 -0
@@ -10,4 +10,8 @@ KNOCK_LICENSE = GPLv2+
 KNOCK_LICENSE_FILES = COPYING
 KNOCK_DEPENDENCIES = libpcap
 
+ifeq ($(BR2_PREFER_STATIC_LIB)$(BR2_PACKAGE_LIBUSB),yy)
+KNOCK_CONF_OPT = LIBS="-lusb-1.0 -pthread"
+endif

Thanks. However, I've already stated that before, but I continue to wonder if this is the right way to fix this. Shouldn't we instead fix libcap by adding a .pc file and submit that upstream, instead of adding more and more LIBS="-lblah" all over the place? Of course, that's not a comment targeted specifically at your patch (we're doing the same thing for many other packages), but I'm wondering if that's the right thing to do.

Thomas

Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
author
#2 lore raw

PATCH 1/1 package/knock: fix static build with libusb

Thomas, All,

On 2014-06-22 19:08 +0200, Thomas Petazzoni spake thusly:

Quoted 34 lines · Yann E. MORIN
Quoted 33 lines

From: "Yann E. MORIN" <[email protected]>

knock depends on libpcap, that has an optional dependency on libusb. Alas, libpcap does not install a .pc file, so knock does not know that it should link with -lusb-1.0.

When linking dynamically, this is not an issue, since the linker does follow the DT_NEEDED tags of libpcap, and thus pulls libusb-1.0 in at the same time. And since linusb uses threads, libpthread is pulled in as well.

However, when linking statically, all of this fails.

Fix that by telling knock's ./configure what libraries to link with when doing a static build and libusb is enabled.

Fixes:

    http://autobuild.buildroot.net/results/1eb/1eb877ebd9469c9261bf114fc7733819ae3fd562/
Signed-off-by "Yann E. MORIN" <[email protected]>
Cc Gustavo Zacarias <[email protected]>
---
 package/knock/knock.mk | 4 ++++
 1 file changed, 4 insertions(+)
package/knock/knock.mk +0 -0
index 8d2b41e..ace23fa 100644
@@ -10,4 +10,8 @@ KNOCK_LICENSE = GPLv2+
 KNOCK_LICENSE_FILES = COPYING
 KNOCK_DEPENDENCIES = libpcap
Quoted 11 lines

package/knock/knock.mk KNOCK_LICENSE = GPLv2+ · line 15

Quoted 3 lines
package/knock/knock.mk +3 -0
+ifeq ($(BR2_PREFER_STATIC_LIB)$(BR2_PACKAGE_LIBUSB),yy)
+KNOCK_CONF_OPT = LIBS="-lusb-1.0 -pthread"
+endif

Thanks. However, I've already stated that before, but I continue to wonder if this is the right way to fix this. Shouldn't we instead fix libcap by adding a .pc file and submit that upstream, instead of adding more and more LIBS="-lblah" all over the place? Of course, that's not a comment targeted specifically at your patch (we're doing the same thing for many other packages), but I'm wondering if that's the right thing to do.

Well, in an ideal world, that'd be good. But even if libpcap did provide a .pc file, then we'd need to patch knock to use pkg-config, which it currently does not.

But I anyway withdraw this patch, in favour to the one recently sent by Baruch:

    http://patchwork.ozlabs.org/patch/362567/

Regards,
Yann E. MORIN.

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#3 lore raw

PATCH 1/1 package/knock: fix static build with libusb

In reply to Yann E. MORIN

Hi Yann,

Quoted 5 lines · Yann E. MORIN

From: "Yann E. MORIN" <[email protected]>

knock depends on libpcap, that has an optional dependency on libusb. Alas, libpcap does not install a .pc file, so knock does not know that it should link with -lusb-1.0.

But libpcap does provide pcap-config for this. We already use it to fix static build against libpcap in a number of packages. Just posted a patch doing the same for knock.

baruch

Quoted 33 lines

When linking dynamically, this is not an issue, since the linker does follow the DT_NEEDED tags of libpcap, and thus pulls libusb-1.0 in at the same time. And since linusb uses threads, libpthread is pulled in as well.

However, when linking statically, all of this fails.

Fix that by telling knock's ./configure what libraries to link with when doing a static build and libusb is enabled.

Fixes:

    http://autobuild.buildroot.net/results/1eb/1eb877ebd9469c9261bf114fc7733819ae3fd562/
Signed-off-by "Yann E. MORIN" <[email protected]>
Cc Gustavo Zacarias <[email protected]>
---
 package/knock/knock.mk | 4 ++++
 1 file changed, 4 insertions(+)
package/knock/knock.mk +4 -0
index 8d2b41e..ace23fa 100644
@@ -10,4 +10,8 @@ KNOCK_LICENSE = GPLv2+
 KNOCK_LICENSE_FILES = COPYING
 KNOCK_DEPENDENCIES = libpcap
 
+ifeq ($(BR2_PREFER_STATIC_LIB)$(BR2_PACKAGE_LIBUSB),yy)
+KNOCK_CONF_OPT = LIBS="-lusb-1.0 -pthread"
+endif
+
 $(eval $(autotools-package))
Signature · 3 lines
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -