build: Allow static linking

To allow static linking, we have to make the libnss dependency
optional. This means the hostname IP resolution feature is not
available in this configuration.

Also the libystemd dependency check doesn't take into account that we
want to link statically. Lukily we just need this for an example.

Currently, the OpenSSL library build will fail in the example
(dependency on libnss) but the library is available to link.

Signed-off-by: Daniel Wagner <[email protected]>

Author: dwsuse

.github/cross/ubuntu-static.txt

@@ -0,0 +1,6 @@
+[properties]
+c_args = '-static'
+cpp_args = c_args
+
+[binaries]
+c = '/usr/bin/gcc'

.github/workflows/meson.yml

@@ -112,7 +112,7 @@ jobs:
           name: Linux_Meson_log
           path: build/meson-logs/meson-log.txt
 
-  build-static:
+  build-with-libray-static:
     runs-on: ubuntu-latest
     steps:
       - name: install libraries
@@ -134,6 +134,28 @@ jobs:
           name: Linux_Meson_log
           path: build/meson-logs/meson-log.txt
 
+  build-static:
+    runs-on: ubuntu-latest
+    steps:
+      - name: install libraries
+        run: sudo apt-get install -y libpam-dev libcap-ng-dev
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.x'
+      - uses: BSFishy/[email protected]
+        with:
+          setup-options: --werror --wrap-mode=forcefallback --cross-file=.github/cross/ubuntu-static.txt --default-library=static
+          options: --verbose
+          action: test
+          meson-version: 0.61.2
+      # Preserve meson's log file on failure
+      - uses: actions/upload-artifact@v3
+        if: failure()
+        with:
+          name: Linux_Meson_log
+          path: build/meson-logs/meson-log.txt
+
   code-coverage:
     runs-on: ubuntu-latest
     steps:

meson.build

@@ -91,7 +91,20 @@ endif
 
 # Check for libsystemd availability. Optional, only required for MCTP dbus scan
 libsystemd_dep = dependency('libsystemd', version: '>219', required: false)
-conf.set('CONFIG_LIBSYSTEMD', libsystemd_dep.found(), description: 'Is libsystemd(>219) available?')
+if libsystemd_dep.found()
+  if cc.links('''#include <systemd/sd-bus.h>
+                 int main(void) {
+                     struct sd_bus *ret;
+                     return sd_bus_default(&ret);
+                 }
+               ''',
+              dependencies: libsystemd_dep,
+              name: 'Link check')
+       conf.set('CONFIG_LIBSYSTEMD', libsystemd_dep.found(), description: 'Is libsystemd(>219) available?')
+  else
+    libsystemd_dep = dependency('', required: false)
+  endif
+endif
 
 # local (cross-compilable) implementations of ccan configure steps
 conf.set10(
@@ -180,6 +193,19 @@ conf.set10(
     description: 'Is linux/mctp.h include-able?'
 )
 
+conf.set(
+    'HAVE_LIBNSS',
+    cc.links(
+      '''int main(int argc, char **argv) {
+             struct addrinfo hints, *result;
+             return getaddrinfo(argv[1], argv[2], &hints, &result);
+      }
+      ''',
+      name: 'havelibnss',
+    ),
+    description: 'Is network address and service translation available'
+)
+
 if cc.has_function_attribute('fallthrough')
   conf.set('fallthrough', '__attribute__((__fallthrough__))')
 else

src/nvme/util.c

@@ -573,6 +573,7 @@ const char *nvme_errno_to_string(int status)
 	return s;
 }
 
+#ifdef HAVE_LIBNSS
 char *hostname2traddr(struct nvme_root *r, const char *traddr)
 {
 	struct addrinfo *host_info, hints = {.ai_family = AF_UNSPEC};
@@ -617,6 +618,18 @@ char *hostname2traddr(struct nvme_root *r, const char *traddr)
 	return ret_traddr;
 }
 
+#else  /* !HAVE_LIBNSS */
+
+char *hostname2traddr(struct nvme_root *r, const char *traddr)
+{
+	nvme_msg(NULL, LOG_ERR, "No support for hostname IP address resolution; " \
+		"recompile with libnss support.\n");
+
+	errno = -ENOTSUP;
+	return NULL;
+}
+#endif /* HAVE_LIBNSS */
+
 char *startswith(const char *s, const char *prefix)
 {
 	size_t l;