[PATCH 3/3] mini-os: fix several memory leaks related to xenbus

[Juergen Gross <jgross@xxxxxxxx>]

There are several instances of calls to xenbus functions which don't
test for an error and in consequence are not freeing the returned
error strings, or which are just not freeing the string after e.g.
printing it.

Fix that by either adding the needed calls of free().

Coverity-ID: 1433632
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 blkfront.c       |  4 ++--
 console/xenbus.c |  2 +-
 fbfront.c        |  4 ++--
 netfront.c       |  2 +-
 pcifront.c       | 28 +++++++++++++---------------
 shutdown.c       |  2 +-
 xenbus/xenbus.c  |  2 ++
 7 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/blkfront.c b/blkfront.c
index f747216..834a978 100644
--- a/blkfront.c
+++ b/blkfront.c
@@ -200,7 +200,7 @@ done:
 
         snprintf(path, sizeof(path), "%s/state", dev->backend);
 
-        xenbus_watch_path_token(XBT_NIL, path, path, &dev->events);
+        free(xenbus_watch_path_token(XBT_NIL, path, path, &dev->events));
 
         msg = NULL;
         state = xenbus_read_integer(path);
@@ -208,7 +208,7 @@ done:
             msg = xenbus_wait_for_state_change(path, &state, &dev->events);
         if (msg != NULL || state != XenbusStateConnected) {
             printk("backend not available, state=%d\n", state);
-            xenbus_unwatch_path_token(XBT_NIL, path, path);
+            free(xenbus_unwatch_path_token(XBT_NIL, path, path));
             goto error;
         }
 
diff --git a/console/xenbus.c b/console/xenbus.c
index 654b469..05fc31c 100644
--- a/console/xenbus.c
+++ b/console/xenbus.c
@@ -164,7 +164,7 @@ done:
         char path[strlen(dev->backend) + strlen("/state") + 1];
         snprintf(path, sizeof(path), "%s/state", dev->backend);
         
-       xenbus_watch_path_token(XBT_NIL, path, path, &dev->events);
+       free(xenbus_watch_path_token(XBT_NIL, path, path, &dev->events));
         msg = NULL;
         state = xenbus_read_integer(path);
         while (msg == NULL && state < XenbusStateConnected)
diff --git a/fbfront.c b/fbfront.c
index 9cc07b4..d3b3848 100644
--- a/fbfront.c
+++ b/fbfront.c
@@ -163,7 +163,7 @@ done:
 
         snprintf(path, sizeof(path), "%s/state", dev->backend);
 
-        xenbus_watch_path_token(XBT_NIL, path, path, &dev->events);
+        free(xenbus_watch_path_token(XBT_NIL, path, path, &dev->events));
 
         err = NULL;
         state = xenbus_read_integer(path);
@@ -530,7 +530,7 @@ done:
 
         snprintf(path, sizeof(path), "%s/state", dev->backend);
 
-        xenbus_watch_path_token(XBT_NIL, path, path, &dev->events);
+        free(xenbus_watch_path_token(XBT_NIL, path, path, &dev->events));
 
         err = NULL;
         state = xenbus_read_integer(path);
diff --git a/netfront.c b/netfront.c
index fe7bb62..66f2bbc 100644
--- a/netfront.c
+++ b/netfront.c
@@ -513,7 +513,7 @@ done:
             err = xenbus_wait_for_state_change(path, &state, &dev->events);
         if (state != XenbusStateConnected) {
             printk("backend not avalable, state=%d\n", state);
-            xenbus_unwatch_path_token(XBT_NIL, path, path);
+            free(xenbus_unwatch_path_token(XBT_NIL, path, path));
             goto error;
         }
 
diff --git a/pcifront.c b/pcifront.c
index 0fc5b30..5642356 100644
--- a/pcifront.c
+++ b/pcifront.c
@@ -70,28 +70,28 @@ void pcifront_watches(void *opaque)
 
     while (1) {
         printk("pcifront_watches: waiting for backend path to appear %s\n", 
path);
-        xenbus_watch_path_token(XBT_NIL, path, path, &events);
+        free(xenbus_watch_path_token(XBT_NIL, path, path, &events));
         while ((err = xenbus_read(XBT_NIL, path, &be_path)) != NULL) {
             free(err);
             xenbus_wait_for_watch(&events);
         }
-        xenbus_unwatch_path_token(XBT_NIL, path, path);
+        free(xenbus_unwatch_path_token(XBT_NIL, path, path));
         printk("pcifront_watches: waiting for backend to get into the right 
state %s\n", be_path);
         be_state = (char *) malloc(strlen(be_path) +  7);
         snprintf(be_state, strlen(be_path) +  7, "%s/state", be_path);
-        xenbus_watch_path_token(XBT_NIL, be_state, be_state, &events);
+        free(xenbus_watch_path_token(XBT_NIL, be_state, be_state, &events));
         while ((err = xenbus_read(XBT_NIL, be_state, &msg)) != NULL || msg[0] 
> '4') {
             free(msg);
             free(err);
             xenbus_wait_for_watch(&events);
         }
-        xenbus_unwatch_path_token(XBT_NIL, be_state, be_state);
+        free(xenbus_unwatch_path_token(XBT_NIL, be_state, be_state));
         if (init_pcifront(NULL) == NULL) {
             free(be_state);
             free(be_path);
             continue;
         }
-        xenbus_watch_path_token(XBT_NIL, be_state, be_state, &events);
+        free(xenbus_watch_path_token(XBT_NIL, be_state, be_state, &events));
         state = XenbusStateConnected;
         printk("pcifront_watches: waiting for backend events %s\n", be_state);
         while ((err = xenbus_wait_for_state_change(be_state, &state, &events)) 
== NULL &&
@@ -103,10 +103,9 @@ void pcifront_watches(void *opaque)
                 if ((err = xenbus_switch_state(XBT_NIL, fe_state, 
XenbusStateReconfiguring)) != NULL) {
                     printk("pcifront_watches: error changing state to %d: 
%s\n",
                             XenbusStateReconfiguring, err);
-                    if (!strcmp(err, "ENOENT")) {
-                        xenbus_write(XBT_NIL, fe_state, "7");
-                        free(err);
-                    }
+                    if (!strcmp(err, "ENOENT"))
+                        free(xenbus_write(XBT_NIL, fe_state, "7"));
+                    free(err);
                 }
             } else if (state == XenbusStateReconfigured) {
                 printk("pcifront_watches: writing %s %d\n", fe_state, 
XenbusStateConnected);
@@ -114,10 +113,9 @@ void pcifront_watches(void *opaque)
                 if ((err = xenbus_switch_state(XBT_NIL, fe_state, 
XenbusStateConnected)) != NULL) {
                     printk("pcifront_watches: error changing state to %d: 
%s\n",
                             XenbusStateConnected, err);
-                    if (!strcmp(err, "ENOENT")) {
-                        xenbus_write(XBT_NIL, fe_state, "4");
-                        free(err);
-                    }
+                    if (!strcmp(err, "ENOENT"))
+                        free(xenbus_write(XBT_NIL, fe_state, "4"));
+                    free(err);
                 }
             } else if (state == XenbusStateClosing)
                 break;
@@ -135,7 +133,7 @@ void pcifront_watches(void *opaque)
         pcidev = NULL;
     }
 
-    xenbus_unwatch_path_token(XBT_NIL, path, path);
+    free(xenbus_unwatch_path_token(XBT_NIL, path, path));
 }
 
 struct pcifront_dev *init_pcifront(char *_nodename)
@@ -243,7 +241,7 @@ done:
         XenbusState state;
         snprintf(path, sizeof(path), "%s/state", dev->backend);
 
-        xenbus_watch_path_token(XBT_NIL, path, path, &dev->events);
+        free(xenbus_watch_path_token(XBT_NIL, path, path, &dev->events));
 
         err = NULL;
         state = xenbus_read_integer(path);
diff --git a/shutdown.c b/shutdown.c
index c7c92cb..4c0b13c 100644
--- a/shutdown.c
+++ b/shutdown.c
@@ -71,7 +71,7 @@ static void shutdown_thread(void *p)
     char *shutdown, *err;
     unsigned int shutdown_reason;
 
-    xenbus_watch_path_token(XBT_NIL, path, token, &events);
+    free(xenbus_watch_path_token(XBT_NIL, path, token, &events));
 
     for ( ;; ) {
         xenbus_wait_for_watch(&events);
diff --git a/xenbus/xenbus.c b/xenbus/xenbus.c
index b12cef7..9e61930 100644
--- a/xenbus/xenbus.c
+++ b/xenbus/xenbus.c
@@ -198,6 +198,8 @@ exit:
         }
         if (msg == NULL && msg2 != NULL)
             msg = msg2;
+        else
+            free(msg2);
     } while (retry);
 
     return msg;
-- 
2.16.4