[PATCH v5 5/9] migration: convert exec backend to accept MigrateAddress struct.

[Het Gala]

Exec transport backend for 'migrate'/'migrate-incoming' QAPIs accept
new wire protocol of MigrateAddress struct.

It is achived by parsing 'uri' string and storing migration parameters
required for exec connection into strList struct.

Suggested-by: Aravind Retnakaran <aravind.retnakaran@nutanix.com>
Signed-off-by: Het Gala <het.gala@nutanix.com>
---
 migration/exec.c      | 60 +++++++++++++++++++++++++++++++------------
 migration/exec.h      |  4 +--
 migration/migration.c | 10 +++-----
 3 files changed, 50 insertions(+), 24 deletions(-)

diff --git a/migration/exec.c b/migration/exec.c
index c4a3293246..a4f02b207f 100644
--- a/migration/exec.c
+++ b/migration/exec.c
@@ -39,19 +39,47 @@ const char *exec_get_cmd_path(void)
 }
 #endif
 
-void exec_start_outgoing_migration(MigrationState *s, const char *command,
+/* provides the length of strList */
+static int
+str_list_length(strList *list)
+{
+    int len = 0;
+    strList *elem;
+
+    for (elem = list; elem != NULL; elem = elem->next) {
+        len++;
+    }
+
+    return len;
+}
+
+static void
+init_exec_array(strList *command, char **argv, Error **errp)
+{
+    int i = 0;
+    strList *lst;
+
+    for (lst = command; lst; lst = lst->next) {
+        argv[i++] = lst->value;
+    }
+
+    argv[i] = NULL;
+    return;
+}
+
+void exec_start_outgoing_migration(MigrationState *s, strList *command,
                                    Error **errp)
 {
     QIOChannel *ioc;
 
-#ifdef WIN32
-    const char *argv[] = { exec_get_cmd_path(), "/c", command, NULL };
-#else
-    const char *argv[] = { "/bin/sh", "-c", command, NULL };
-#endif
+    int length = str_list_length(command);
+    g_auto(GStrv) argv = (char **) g_new0(const char *, length);
 
-    trace_migration_exec_outgoing(command);
-    ioc = QIO_CHANNEL(qio_channel_command_new_spawn(argv,
+    init_exec_array(command, argv, errp);
+    g_autofree char *new_command = g_strjoinv(" ", (char **)argv);
+
+    trace_migration_exec_outgoing(new_command);
+    ioc = QIO_CHANNEL(qio_channel_command_new_spawn((const char * const*) argv,
                                                     O_RDWR,
                                                     errp));
     if (!ioc) {
@@ -72,18 +100,18 @@ static gboolean exec_accept_incoming_migration(QIOChannel 
*ioc,
     return G_SOURCE_REMOVE;
 }
 
-void exec_start_incoming_migration(const char *command, Error **errp)
+void exec_start_incoming_migration(strList *command, Error **errp)
 {
     QIOChannel *ioc;
 
-#ifdef WIN32
-    const char *argv[] = { exec_get_cmd_path(), "/c", command, NULL };
-#else
-    const char *argv[] = { "/bin/sh", "-c", command, NULL };
-#endif
+    int length = str_list_length(command);
+    g_auto(GStrv) argv = (char **) g_new0(const char *, length);
+
+    init_exec_array(command, argv, errp);
+    g_autofree char *new_command = g_strjoinv(" ", (char **)argv);
 
-    trace_migration_exec_incoming(command);
-    ioc = QIO_CHANNEL(qio_channel_command_new_spawn(argv,
+    trace_migration_exec_incoming(new_command);
+    ioc = QIO_CHANNEL(qio_channel_command_new_spawn((const char * const*) argv,
                                                     O_RDWR,
                                                     errp));
     if (!ioc) {
diff --git a/migration/exec.h b/migration/exec.h
index 736cd71028..3107f205e3 100644
--- a/migration/exec.h
+++ b/migration/exec.h
@@ -23,8 +23,8 @@
 #ifdef WIN32
 const char *exec_get_cmd_path(void);
 #endif
-void exec_start_incoming_migration(const char *host_port, Error **errp);
+void exec_start_incoming_migration(strList *host_port, Error **errp);
 
-void exec_start_outgoing_migration(MigrationState *s, const char *host_port,
+void exec_start_outgoing_migration(MigrationState *s, strList *host_port,
                                    Error **errp);
 #endif
diff --git a/migration/migration.c b/migration/migration.c
index b7c72fafc9..0a6ab9229b 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -465,7 +465,6 @@ static bool migrate_uri_parse(const char *uri, 
MigrateAddress **channel,
 
 static void qemu_start_incoming_migration(const char *uri, Error **errp)
 {
-    const char *p = NULL;
     g_autoptr(MigrateAddress) channel = g_new0(MigrateAddress, 1);
 
     /* URI is not suitable for migration? */
@@ -491,8 +490,8 @@ static void qemu_start_incoming_migration(const char *uri, 
Error **errp)
     } else if (channel->transport == MIGRATE_TRANSPORT_RDMA) {
         rdma_start_incoming_migration(&channel->u.rdma, errp);
 #endif
-    } else if (strstart(uri, "exec:", &p)) {
-        exec_start_incoming_migration(p, errp);
+    } else if (channel->transport == MIGRATE_TRANSPORT_EXEC) {
+        exec_start_incoming_migration(channel->u.exec.args, errp);
     } else {
         error_setg(errp, "unknown migration protocol: %s", uri);
     }
@@ -1682,7 +1681,6 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
 {
     Error *local_err = NULL;
     MigrationState *s = migrate_get_current();
-    const char *p = NULL;
     g_autoptr(MigrateAddress) channel = g_new0(MigrateAddress, 1);
 
     /* URI is not suitable for migration? */
@@ -1719,8 +1717,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     } else if (channel->transport == MIGRATE_TRANSPORT_RDMA) {
         rdma_start_outgoing_migration(s, &channel->u.rdma, &local_err);
 #endif
-    } else if (strstart(uri, "exec:", &p)) {
-        exec_start_outgoing_migration(s, p, &local_err);
+    } else if (channel->transport == MIGRATE_TRANSPORT_EXEC) {
+        exec_start_outgoing_migration(s, channel->u.exec.args, &local_err);
     } else {
         if (!(has_resume && resume)) {
             yank_unregister_instance(MIGRATION_YANK_INSTANCE);
-- 
2.22.3