MonetDB: Jul2012 - multiplex-funnel: fix memleaks when notifying...

[Fabian Groffen]

Changeset: ff0763a6b2c0 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=ff0763a6b2c0
Modified Files:
        tools/merovingian/daemon/multiplex-funnel.c
Branch: Jul2012
Log Message:

multiplex-funnel: fix memleaks when notifying of added/removed dbs

The internal message passing system uses pointers to strings.  This
means all passed messages must be allocated (on the heap).  In that
case, one thread allocates, the other one has to free.  The latter seems
to have been forgotten.

This caused a memleak when the multiplex-funnel was switching targets.


diffs (76 lines):

diff --git a/tools/merovingian/daemon/multiplex-funnel.c 
b/tools/merovingian/daemon/multiplex-funnel.c
--- a/tools/merovingian/daemon/multiplex-funnel.c
+++ b/tools/merovingian/daemon/multiplex-funnel.c
@@ -64,7 +64,6 @@ MFconnectionManager(void *d)
        multiplexlist *w;
        char buf[1024];
        size_t len;
-       void *p;
        char *msg;
        struct timeval tv;
        fd_set fds;
@@ -86,12 +85,12 @@ MFconnectionManager(void *d)
                                        strerror(errno));
                        break;
                }
-               if (read(mfpipe[0], &p, sizeof(void *)) < 0) {
+               if (read(mfpipe[0], &msg, sizeof(msg)) < 0) {
                        Mfprintf(stderr, "failed reading from notification 
pipe: %s\n",
                                        strerror(errno));
                        break;
                }
-               msg = (char *)p;
+               /* we just received a POINTER to a string! */
 
                /* intended behaviour:
                 * - additions don't change any connection targets, they only
@@ -225,6 +224,8 @@ MFconnectionManager(void *d)
                        }
                }
                pthread_mutex_unlock(&mpl_lock);
+
+               free(msg); /* alloced by multiplexNotify* */
        }
 }
 
@@ -232,30 +233,36 @@ void
 multiplexNotifyAddedDB(const char *database)
 {
        char dbslash[256];
-       void *p;
+       char *p;
 
        if (mfmanager == 0)
                return;
 
        snprintf(dbslash, sizeof(dbslash), "+%s/", database);
        p = strdup(dbslash);
-       if (write(mfpipe[1], &p, sizeof(void *)) != sizeof(void *))
+       if (write(mfpipe[1], &p, sizeof(p)) != sizeof(p)) {
                Mfprintf(stderr, "failed to write notify added message to 
mfpipe\n");
+               free(p);
+       }
+       /* p is freed by MFconnectionManager */
 }
 
 void
 multiplexNotifyRemovedDB(const char *database)
 {
        char dbslash[256];
-       void *p;
+       char *p;
 
        if (mfmanager == 0)
                return;
 
        snprintf(dbslash, sizeof(dbslash), "-%s/", database);
        p = strdup(dbslash);
-       if (write(mfpipe[1], &p, sizeof(void *)) != sizeof(void *))
+       if (write(mfpipe[1], &p, sizeof(p)) != sizeof(p)) {
                Mfprintf(stderr, "failed to write notify removed message to 
mfpipe\n");
+               free(p);
+       }
+       /* p is freed by MFconnectionManager */
 }
 
 /* ultra ugly, we peek inside Sabaoth's internals to update the uplog
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