[dpdk-dev] [PATCH v8 6/6] build: use dependency for pcap and fallback to find_library

[luca.boccassi@gmail.com]

From: Luca Boccassi <luca.boccassi@microsoft.com>

pcap has historically shipped a custom pcap-config binary tool which
does the job of pkg-config. It was never compatible with cross
compilation.
Meson uses it when using dependency(), which then means cross
compilation fails.
Set pcap-config to empty in the meson cross compilation files so
that Meson will not use it, and add a fallback in case
dependency() fails.
libpcap 1.9.0 finally ships a pkg-config file so everything will
work out of the box in the future.

Signed-off-by: Luca Boccassi <luca.boccassi@microsoft.com>
---
v8: added back pcap change separately. Tested with bootlin
    cross-compilation toolchain, everything seems to work.

 config/arm/arm64_armv8_linuxapp_gcc    |  1 +
 config/arm/arm64_dpaa2_linuxapp_gcc    |  1 +
 config/arm/arm64_dpaa_linuxapp_gcc     |  1 +
 config/arm/arm64_thunderx_linuxapp_gcc |  1 +
 drivers/net/pcap/meson.build           | 16 ++++++++++++----
 5 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/config/arm/arm64_armv8_linuxapp_gcc b/config/arm/arm64_armv8_linuxapp_gcc
index 987c02fbb..513760917 100644
--- a/config/arm/arm64_armv8_linuxapp_gcc
+++ b/config/arm/arm64_armv8_linuxapp_gcc
@@ -3,6 +3,7 @@ c = 'aarch64-linux-gnu-gcc'
 cpp = 'aarch64-linux-gnu-cpp'
 ar = 'aarch64-linux-gnu-gcc-ar'
 strip = 'aarch64-linux-gnu-strip'
+pcap-config = ''
 
 [host_machine]
 system = 'linux'
diff --git a/config/arm/arm64_dpaa2_linuxapp_gcc b/config/arm/arm64_dpaa2_linuxapp_gcc
index 7ec74ec4b..0df8c8f7d 100644
--- a/config/arm/arm64_dpaa2_linuxapp_gcc
+++ b/config/arm/arm64_dpaa2_linuxapp_gcc
@@ -4,6 +4,7 @@ cpp = 'aarch64-linux-gnu-cpp'
 ar = 'aarch64-linux-gnu-ar'
 as = 'aarch64-linux-gnu-as'
 strip = 'aarch64-linux-gnu-strip'
+pcap-config = ''
 
 [host_machine]
 system = 'linux'
diff --git a/config/arm/arm64_dpaa_linuxapp_gcc b/config/arm/arm64_dpaa_linuxapp_gcc
index 73a8f0b81..f4b85a84b 100644
--- a/config/arm/arm64_dpaa_linuxapp_gcc
+++ b/config/arm/arm64_dpaa_linuxapp_gcc
@@ -4,6 +4,7 @@ cpp = 'aarch64-linux-gnu-cpp'
 ar = 'aarch64-linux-gnu-ar'
 as = 'aarch64-linux-gnu-as'
 strip = 'aarch64-linux-gnu-strip'
+pcap-config = ''
 
 [host_machine]
 system = 'linux'
diff --git a/config/arm/arm64_thunderx_linuxapp_gcc b/config/arm/arm64_thunderx_linuxapp_gcc
index 967d9d46d..14b801998 100644
--- a/config/arm/arm64_thunderx_linuxapp_gcc
+++ b/config/arm/arm64_thunderx_linuxapp_gcc
@@ -3,6 +3,7 @@ c = 'aarch64-linux-gnu-gcc'
 cpp = 'aarch64-linux-gnu-cpp'
 ar = 'aarch64-linux-gnu-gcc-ar'
 strip = 'aarch64-linux-gnu-strip'
+pcap-config = ''
 
 [host_machine]
 system = 'linux'
diff --git a/drivers/net/pcap/meson.build b/drivers/net/pcap/meson.build
index 0c4e0201a..2c2fd11e4 100644
--- a/drivers/net/pcap/meson.build
+++ b/drivers/net/pcap/meson.build
@@ -1,12 +1,20 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-pcap_dep = cc.find_library('pcap', required: false)
-if pcap_dep.found() and cc.has_header('pcap.h', dependencies: pcap_dep)
+pcap_dep = dependency('pcap', required: false)
+if pcap_dep.found()
 	build = true
 else
-	build = false
+	# pcap got a pkg-config file only in 1.9.0 and before that meson uses
+	# an internal pcap-config finder, which is not compatible with
+	# cross-compilation, so try to fallback to find_library
+	pcap_dep = cc.find_library('pcap', required: false)
+	if pcap_dep.found() and cc.has_header('pcap.h', dependencies: pcap_dep)
+		build = true
+		pkgconfig_extra_libs += '-lpcap'
+	else
+		build = false
+	endif
 endif
 sources = files('rte_eth_pcap.c')
 ext_deps += pcap_dep
-pkgconfig_extra_libs += '-lpcap'
-- 
2.20.1