[Nbd] [PATCH 2/2] nbd-server: Make command-line -r apply to all exports

[Eric Blake <eblake@...696...>]

Now that we prefer the config file for everything, many command
line options don't make much sense any more.  But one common
tweak is a decision on whether to fire up nbd-server with all
exports as read-only.  Repurpose the -r command line option to
imply that all exports are now readonly, rather than just the
ones mentioned as readonly in the config, which makes it easier
to test a server setup without the worry of accidental writes
while also avoiding the need to tweak the config file just to
turn lots of readonly markers on and then back off again.

Signed-off-by: Eric Blake <eblake@...696...>
---
 man/nbd-server.1.in.sgml | 5 +++--
 man/nbd-server.5.in.sgml | 2 +-
 nbd-server.c             | 7 ++++++-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/man/nbd-server.1.in.sgml b/man/nbd-server.1.in.sgml
index d1d4301..16b6411 100644
--- a/man/nbd-server.1.in.sgml
+++ b/man/nbd-server.1.in.sgml
@@ -159,9 +159,10 @@ manpage.1: manpage.sgml
       <varlistentry>
 	<term><option>-r</option></term>
 	<listitem>
-	  <para>Export the file read-only. If a client tries to write
+	  <para>Export all files as read-only. If a client tries to write
 	    to a read-only exported file, it will receive an error, but
-	    the connection will stay up.</para>
+	    the connection will stay up. This option overrides the
+	    configuration file per-export readonly settings.</para>
 	</listitem>
       </varlistentry>
       <varlistentry>
diff --git a/man/nbd-server.5.in.sgml b/man/nbd-server.5.in.sgml
index e838bcf..03ded44 100644
--- a/man/nbd-server.5.in.sgml
+++ b/man/nbd-server.5.in.sgml
@@ -684,7 +684,7 @@ manpage.1: manpage.sgml
 	    Use of this option in conjunction with
 	    <option>copyonwrite</option> is possible, but silly.
 	  </para>
-	  <para>Corresponds to the <option>-r</option> option on the
+	  <para>Implied if the <option>-r</option> option is used on the
 	  command line.</para>
 	</listitem>
       </varlistentry>
diff --git a/nbd-server.c b/nbd-server.c
index 698e86e..cb341f6 100644
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -164,6 +164,7 @@ int dontfork = 0;
 #define F_OLDSTYLE 1	  /**< Allow oldstyle (port-based) exports */
 #define F_LIST 2	  /**< Allow clients to list the exports on a server */
 #define F_NO_ZEROES 4	  /**< Do not send zeros to client */
+#define F_ALL_READONLY 8  /**< Force all exports to be readonly */
 // also accepts F_FORCEDTLS (which is 16384)
 GHashTable *children;
 char pidfname[256]; /**< name of our PID file */
@@ -440,7 +441,7 @@ static inline void spliceit(int fd_in, loff_t *off_in, int fd_out,
 void usage() {
 	printf("This is nbd-server version " VERSION "\n");
 	printf("Usage: [[ip:|ip6@]port file_to_export [size][kKmM]] [-l authorize_file] [-r] [-m] [-c] [-C configuration file] [-p PID file name] [-o section name] [-M max connections] [-d] [-V]\n"
-	       "\t-r|--read-only\t\tread only\n"
+	       "\t-r|--read-only\t\tmake all exports be read only\n"
 	       "\t-m|--multi-file\t\tmultiple file\n"
 	       "\t-c|--copy-on-write\tcopy on write\n"
 	       "\t-C|--config-file\tspecify an alternate configuration file\n"
@@ -577,6 +578,7 @@ SERVER* cmdline(int argc, char *argv[], struct generic_conf *genconf) {
 			}
 			break;
 		case 'r':
+			genconf->flags |= F_ALL_READONLY;
 			serve->flags |= F_READONLY;
 			break;
 		case 'm':
@@ -945,6 +947,9 @@ GArray* parse_cfile(gchar* f, struct generic_conf *const genconf, bool expect_ge
 		/* Don't append values for the [generic] group */
 		if(i>0 || !expect_generic) {
 			s.servename = groups[i];
+			if (genconftmp.flags & F_ALL_READONLY) {
+				s.flags |= F_READONLY;
+			}

 			g_array_append_val(retval, s);
 		}
-- 
2.9.3