build: fix musl build errors

libgen.h must be included to silence a compiler error regarding the
basename() function missing when building with musl libc.

The basename() function call in libnvme/src/nvme/linux.c:__nvme_transport_handle_open_direct()
causes a (fatal) compilation warning due to GNU using this declaration of basename:
char *basename (const char *filename)
and POSIX (and also musl) ommiting const. It is thus possible that the const char *devname
would be modified by basename().

The solution to the problem above is to use the internal implementation of basename from glibc
directly and avoid these API compatibility problems.

Signed-off-by: Michal Rábek <[email protected]>

Author: MichaelRabek

libnvme/src/nvme/linux.c

@@ -12,6 +12,10 @@
 #include <string.h>
 #include <errno.h>
 
+#ifndef _GNU_SOURCE
+#include <libgen.h>
+#endif
+
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -83,7 +87,7 @@ static int __nvme_transport_handle_open_direct(struct nvme_transport_handle *hdl
 {
 	struct nvme_passthru_cmd dummy = { 0 };
 	_cleanup_free_ char *path = NULL;
-	char *name = basename(devname);
+	const char *name = nvme_basename(devname);
 	int ret, id, ns;
 	bool c = true;
 

libnvme/src/nvme/util.c

@@ -1179,3 +1179,12 @@ const struct ifaddrs *nvme_getifaddrs(struct nvme_global_ctx *ctx)
 
 	return ctx->ifaddrs_cache;
 }
+
+/* This used instead of basename() due to behavioral differences between
+ * the POSIX and the GNU version. This is the glibc implementation.
+ * Original source: https://github.com/bminor/glibc/blob/master/string/basename.c */
+char *nvme_basename(const char *path)
+{
+	char *p = strrchr (path, '/');
+	return p ? p + 1 : (char *) path;
+}

libnvme/src/nvme/util.h

@@ -785,4 +785,12 @@ const char *nvme_iface_matching_addr(const struct ifaddrs *iface_list, const cha
  */
 bool nvme_iface_primary_addr_matches(const struct ifaddrs *iface_list, const char *iface, const char *addr);
 
+/**
+ * nvme_basename - Return the final path component (the one after the last '/')
+ * @path: A string containing a filesystem path
+ *
+ * Return: A pointer into the original null-terminated path string.
+ */
+char *nvme_basename(const char *path);
+
 #endif /* _LIBNVME_UTIL_H */