(#22952) libselinux: Fix cross-compilation

* libselinux: Fix cross-compilation

Apply patches for 3.6 to fix detection of available functions when cross-compiling.
Use the PKG_CONFIG_LIBDIR to point pkg-config to the correct directory containing Conan's generated pkg-config files.
Without this, the pcre2 from the system will be picked up before the one provided by Conan.
When cross-compiling, this causes system include directories to poison the build.

* Bump pkgconf

* Only set PKG_CONFIG_LIBDIR when cross-compiling

* Update recipes/libselinux/all/conanfile.py

---------

Co-authored-by: Francisco Ramírez <[email protected]>

recipes/libselinux/all/conandata.yml

@@ -40,6 +40,15 @@ patches:
       base_path: libselinux-3.6
       patch_description: "Fix a missing #include <stdint.h>"
       patch_type: "portability"
+    - patch_file: patches/0004-libsepol-src-Makefile-fix-reallocarray-detection.patch
+      patch_description: "libsepol/src/Makefile: fix reallocarray detection"
+      patch_source: "https://lore.kernel.org/selinux/[email protected]/"
+      patch_type: "portability"
+      base_path: libsepol-3.6
+    - patch_file: patches/0005-libselinux-libsepol-Add-CFLAGS-and-LDFLAGS.patch
+      patch_description: "libselinux, libsepol: Add CFLAGS and LDFLAGS to Makefile checks"
+      patch_source: "https://lore.kernel.org/selinux/[email protected]/T/#u"
+      patch_type: "portability"
   "3.3":
     - patch_file: patches/0003-fix-link-pcre.patch
       base_path: libselinux-3.3

recipes/libselinux/all/conanfile.py

@@ -2,6 +2,7 @@
 
 from conan import ConanFile
 from conan.errors import ConanInvalidConfiguration
+from conan.tools.build import cross_building
 from conan.tools.env import VirtualBuildEnv
 from conan.tools.files import apply_conandata_patches, chdir, copy, export_conandata_patches, get, rename, replace_in_file, save
 from conan.tools.gnu import Autotools, AutotoolsToolchain, PkgConfigDeps
@@ -62,7 +63,7 @@ def validate(self):
     def build_requirements(self):
         self.tool_requires("flex/2.6.4")
         if not self.conf.get("tools.gnu:pkg_config", default=False, check_type=str):
-            self.tool_requires("pkgconf/2.0.3")
+            self.tool_requires("pkgconf/2.2.0")
 
     def source(self):
         for download in self.conan_data["sources"][self.version]:
@@ -87,7 +88,10 @@ def generate(self):
         sepol_lib_folder = os.path.join(self._sepol_source_folder, "src")
         tc.extra_ldflags.append(f"-L{sepol_lib_folder}")
         tc.make_args.append("USE_PCRE2=y")
-        tc.generate()
+        env = tc.environment()
+        if cross_building(self):
+            env.append_path("PKG_CONFIG_LIBDIR", self.generators_folder)
+        tc.generate(env=env)
 
     def build(self):
         apply_conandata_patches(self)

recipes/libselinux/all/patches/0004-libsepol-src-Makefile-fix-reallocarray-detection.patch

@@ -0,0 +1,48 @@
+From a520f972bce9ec267f4e76b729bc3b7c1bdf13e6 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <[email protected]>
+Date: Mon, 8 Jan 2024 22:03:14 +0100
+Subject: [PATCH 1/3] libsepol/src/Makefile: fix reallocarray detection
+
+Pass LDFLAGS when checking for reallocarray to avoid the following
+static build failure with musl raised since version 3.4 and
+https://github.com/SELinuxProject/selinux/commit/f0a5f6e33084bd83d409bb7c932256139f471e71
+because -static is not passed when checking for reallocarray:
+
+/home/autobuild/autobuild/instance-9/output-1/host/bin/armeb-buildroot-linux-musleabi-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O0 -g0  -static -I. -I../include -D_GNU_SOURCE -I../cil/include -fPIC -c -o assertion.o assertion.c
+In file included from assertion.c:28:
+private.h:88:21: error: static declaration of 'reallocarray' follows non-static declaration
+   88 | static inline void* reallocarray(void *ptr, size_t nmemb, size_t size) {
+      |                     ^~~~~~~~~~~~
+In file included from ../include/sepol/policydb/mls_types.h:35,
+                 from ../include/sepol/policydb/context.h:23,
+                 from ../include/sepol/policydb/policydb.h:62,
+                 from assertion.c:24:
+/home/autobuild/autobuild/instance-9/output-1/host/armeb-buildroot-linux-musleabi/sysroot/usr/include/stdlib.h:150:7: note: previous declaration of 'reallocarray' with type 'void *(void *, size_t,  size_t)' {aka 'void *(void *, unsigned int,  unsigned int)'}
+  150 | void *reallocarray (void *, size_t, size_t);
+      |       ^~~~~~~~~~~~
+
+Fixes:
+ - http://autobuild.buildroot.org/results/0170032548a38e2c991d62dc5823808458ad03b3
+
+Signed-off-by: Fabrice Fontaine <[email protected]>
+Acked-by: James Carter <[email protected]>
+---
+src/Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/Makefile b/src/Makefile
+index d80a941f..16b9bd5e 100644
+--- a/src/Makefile
++++ b/src/Makefile
+@@ -31,7 +31,7 @@ endif
+
+ # check for reallocarray(3) availability
+ H := \#
+-ifeq (yes,$(shell printf '${H}define _GNU_SOURCE\n${H}include <stdlib.h>\nint main(void){void*p=reallocarray(NULL, 1, sizeof(char));return 0;}' | $(CC) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
++ifeq (yes,$(shell printf '${H}define _GNU_SOURCE\n${H}include <stdlib.h>\nint main(void){void*p=reallocarray(NULL, 1, sizeof(char));return 0;}' | $(CC) $(LDFLAGS) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
+ override CFLAGS += -DHAVE_REALLOCARRAY
+ endif
+
+-- 
+2.44.0
+

recipes/libselinux/all/patches/0005-libselinux-libsepol-Add-CFLAGS-and-LDFLAGS.patch

@@ -0,0 +1,61 @@
+[PATCH] libselinux, libsepol: Add CFLAGS and LDFLAGS to Makefile checks
+@ 2024-03-13 22:48 James Carter
+  0 siblings, 0 replies; only message in thread
+From: James Carter @ 2024-03-13 22:48 UTC (permalink / raw)
+  To: selinux; +Cc: jordan, winfried_mb2, James Carter
+
+In libselinux there is an availability check for strlcpy() and
+in both libselinux and libsepol there are availability checks for
+reallocarray() in the src Makfiles. CFLAGS and LDFLAGS are needed
+for cross-compiling, but, unfortunately, the default CFLAGS cause
+all of these availability checks to fail to compile because of
+compilationerrors (rather than just the function not being available).
+
+Add CFLAGS and LDFLAGS to the availibility checks, update the checks
+so that a compilation error will only happen if the function being
+checked for is not available, and make checks for the same function
+the same in both libselinux and libsepol.
+
+Suggested-by: Jordan Williams <[email protected]>
+Suggested-by: Winfried Dobbe <[email protected]>
+Signed-off-by: James Carter <[email protected]>
+---
+ libselinux/src/Makefile | 4 ++--
+ libsepol/src/Makefile   | 2 +-
+ 2 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/libselinux-3.6/src/Makefile b/libselinux-3.6/src/Makefile
+index d3b981fc..41cfbdca 100644
+--- a/libselinux-3.6/src/Makefile
++++ b/libselinux-3.6/src/Makefile
+@@ -104,13 +104,13 @@ override CFLAGS += -I../include -D_GNU_SOURCE $(DISABLE_FLAGS) $(PCRE_CFLAGS)
+
+ # check for strlcpy(3) availability
+ H := \#
+-ifeq (yes,$(shell printf '${H}include <string.h>\nint main(void){char*d,*s;strlcpy(d, s, 0);return 0;}' | $(CC) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
++ifeq (yes,$(shell printf '${H}include <string.h>\nint main(void){char d[2];const char *s="a";return (size_t)strlcpy(d,s,sizeof(d))>=sizeof(d);}' | $(CC) $(CFLAGS) $(LDFLAGS) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
+ override CFLAGS += -DHAVE_STRLCPY
+ endif
+
+ # check for reallocarray(3) availability
+ H := \#
+-ifeq (yes,$(shell printf '${H}include <stdlib.h>\nint main(void){reallocarray(NULL, 0, 0);return 0;}' | $(CC) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
++ifeq (yes,$(shell printf '${H}include <stdlib.h>\nint main(void){return reallocarray(NULL,0,0)==NULL;}' | $(CC) $(CFLAGS) $(LDFLAGS) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
+ override CFLAGS += -DHAVE_REALLOCARRAY
+ endif
+
+diff --git a/libsepol-3.6/src/Makefile b/libsepol-3.6/src/Makefile
+index 16b9bd5e..7b0e8446 100644
+--- a/libsepol-3.6/src/Makefile
++++ b/libsepol-3.6/src/Makefile
+@@ -31,7 +31,7 @@ endif
+
+ # check for reallocarray(3) availability
+ H := \#
+-ifeq (yes,$(shell printf '${H}define _GNU_SOURCE\n${H}include <stdlib.h>\nint main(void){void*p=reallocarray(NULL, 1, sizeof(char));return 0;}' | $(CC) $(LDFLAGS) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
++ifeq (yes,$(shell printf '${H}include <stdlib.h>\nint main(void){return reallocarray(NULL,0,0)==NULL;}' | $(CC) $(CFLAGS) $(LDFLAGS) -x c -o /dev/null - >/dev/null 2>&1 && echo yes))
+ override CFLAGS += -DHAVE_REALLOCARRAY
+ endif
+
+-- 
+2.44.0