[Xen-devel] [PATCH] libxl: libxl__spawn_qdisk_backend closes fds

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

This function needs to close both null and logfile_w on both error and
normal exits.  (The child gets its own copy during the fork, and the
parent doesn't need them any more.)

Use the standard initialise-to-unallocated, always-free style; the
label "out" only makes the callback if rc is nonzero.

Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Coverity-ID: 1130517 and 1130518
Cc: Roger Pau Monne <roger.pau@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: coverity@xxxxxxxxxxxxxx
---
 tools/libxl/libxl_dm.c |   15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 8abed7b..d28ea4d 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -1392,7 +1392,7 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, 
libxl__dm_spawn_state *dmss)
     flexarray_t *dm_args;
     char **args;
     const char *dm;
-    int logfile_w, null, rc;
+    int logfile_w = -1, null = -1, rc;
     uint32_t domid = dmss->guest_domid;
 
     /* Always use qemu-xen as device model */
@@ -1448,12 +1448,21 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, 
libxl__dm_spawn_state *dmss)
         libxl__exec(gc, null, logfile_w, logfile_w, dm, args, NULL);
     }
 
+    rc = 0;
+
+ out:
+    if (logfile_w >= 0) close(logfile_w);
+    if (null >= 0) close(null);
+
+    /* rc is nonzero iff we had an error; if we had no error then
+     * spawn succeeded and we will continue in a further callback */
+    if (rc)
+        dmss->callback(egc, dmss, rc);
     return;
 
 error:
     assert(rc);
-    dmss->callback(egc, dmss, rc);
-    return;
+    goto out;
 }
 
 /* Generic function to signal a Qemu instance to exit */
-- 
1.7.10.4


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