Minimal libshare infrastructure

ZFS even under Solaris does not strictly require libshare to be
available.  The current implementation attempts to dlopen() the
library to access the needed symbols.  If this fails libshare
support is simply disabled.

This means that on Linux we only need the most minimal libshare
implementation.  In fact just enough to prevent the build from
failing.  Longer term we can decide if we want to implement a
libshare library like Solaris.  At best this would be an abstraction
layer between ZFS and NFS/SMB.  Alternately, we can drop libshare
entirely and directly integrate ZFS with Linux's NFS/SMB.

Finally the bare bones user-libshare.m4 test was dropped.  If we
do decide to implement libshare at some point it will surely be
as part of this package so the check is not needed.

1 files changed, 11 insertions, 24 deletions

diff --git a/lib/libzfs/libzfs_mount.c b/lib/libzfs/libzfs_mount.c
index 75ce3676f..42036a44b 100644
--- a/lib/libzfs/libzfs_mount.c
+++ b/lib/libzfs/libzfs_mount.c
@@ -121,20 +121,21 @@ zfs_share_proto_t share_all_proto[] = {
 };
 
 /*
- * Search the sharetab for the given mountpoint and protocol, returning
+ * Search for NFS and SMB exports for the given mountpoint and protocol, returning
  * a zfs_share_type_t value.
  */
 static zfs_share_type_t
 is_shared(libzfs_handle_t *hdl, const char *mountpoint, zfs_share_proto_t proto)
 {
 	char buf[MAXPATHLEN], *tab;
-	char *ptr;
 
 	if (hdl->libzfs_sharetab == NULL)
 		return (SHARED_NOT_SHARED);
 
 	(void) fseek(hdl->libzfs_sharetab, 0, SEEK_SET);
 
+	/* Search /etc/exports for NFS exports */
+	/* FIXME: Assumes the file is tab delimited. */
 	while (fgets(buf, sizeof (buf), hdl->libzfs_sharetab) != NULL) {
 
 		/* the mountpoint is the first entry on each line */
@@ -143,31 +144,15 @@ is_shared(libzfs_handle_t *hdl, const char *mountpoint, zfs_share_proto_t proto)
 
 		*tab = '\0';
 		if (strcmp(buf, mountpoint) == 0) {
-			/*
-			 * the protocol field is the third field
-			 * skip over second field
-			 */
-			ptr = ++tab;
-			if ((tab = strchr(ptr, '\t')) == NULL)
-				continue;
-			ptr = ++tab;
-			if ((tab = strchr(ptr, '\t')) == NULL)
-				continue;
-			*tab = '\0';
-			if (strcmp(ptr,
-			    proto_table[proto].p_name) == 0) {
-				switch (proto) {
-				case PROTO_NFS:
-					return (SHARED_NFS);
-				case PROTO_SMB:
-					return (SHARED_SMB);
-				default:
-					return (0);
-				}
-			}
+			if (proto == PROTO_NFS)
+				return (SHARED_NFS);
+			else
+				return (SHARED_NOT_SHARED);
 		}
 	}
 
+	/* XXX: Search /etc/samba/smb.conf for SMB exports, return SHARED_SMB */
+
 	return (SHARED_NOT_SHARED);
 }
 
@@ -808,10 +793,12 @@ zfs_share_proto(zfs_handle_t *zhp, zfs_share_proto_t *proto)
 		return (0);
 
 	if ((ret = zfs_init_libshare(hdl, SA_INIT_SHARE_API)) != SA_OK) {
+#ifdef HAVE_SHARE
 		(void) zfs_error_fmt(hdl, EZFS_SHARENFSFAILED,
 		    dgettext(TEXT_DOMAIN, "cannot share '%s': %s"),
 		    zfs_get_name(zhp), _sa_errorstr != NULL ?
 		    _sa_errorstr(ret) : "");
+#endif /* HAVE_SHARE */
 		return (-1);
 	}