unixsock plugin: Fix a (well hidden) race condition.

[collectd.git] / src / unixsock.c

diff --git a/src/unixsock.c b/src/unixsock.c
index 6a8628a..38f9025 100644 (file)
--- a/src/unixsock.c
+++ b/src/unixsock.c
@@ -157,32 +157,45 @@ static int us_open_socket (void)
 
 static void *us_handle_client (void *arg)
 {
-       int fd;
+       int fdin;
+       int fdout;
        FILE *fhin, *fhout;
 
-       fd = *((int *) arg);
+       fdin = *((int *) arg);
        free (arg);
        arg = NULL;
 
-       DEBUG ("Reading from fd #%i", fd);
+       DEBUG ("unixsock plugin: us_handle_client: Reading from fd #%i", fdin);
 
-       fhin  = fdopen (fd, "r");
+       fdout = dup (fdin);
+       if (fdout < 0)
+       {
+               char errbuf[1024];
+               ERROR ("unixsock plugin: dup failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
+               close (fdin);
+               pthread_exit ((void *) 1);
+       }
+
+       fhin  = fdopen (fdin, "r");
        if (fhin == NULL)
        {
                char errbuf[1024];
                ERROR ("unixsock plugin: fdopen failed: %s",
                                sstrerror (errno, errbuf, sizeof (errbuf)));
-               close (fd);
+               close (fdin);
+               close (fdout);
                pthread_exit ((void *) 1);
        }
 
-       fhout = fdopen (fd, "w");
+       fhout = fdopen (fdout, "w");
        if (fhout == NULL)
        {
                char errbuf[1024];
                ERROR ("unixsock plugin: fdopen failed: %s",
                                sstrerror (errno, errbuf, sizeof (errbuf)));
-               fclose (fhin); /* this closes fd as well */
+               fclose (fhin); /* this closes fdin as well */
+               close (fdout);
                pthread_exit ((void *) 1);
        }
 
@@ -230,11 +243,12 @@ static void *us_handle_client (void *arg)
 
                fields_num = strsplit (buffer_copy, fields,
                                sizeof (fields) / sizeof (fields[0]));
-
                if (fields_num < 1)
                {
-                       close (fd);
-                       break;
+                       fprintf (fhout, "-1 Internal error\n");
+                       fclose (fhin);
+                       fclose (fhout);
+                       pthread_exit ((void *) 1);
                }
 
                if (strcasecmp (fields[0], "getval") == 0)
@@ -247,11 +261,11 @@ static void *us_handle_client (void *arg)
                }
                else if (strcasecmp (fields[0], "listval") == 0)
                {
-                       handle_listval (fhout, fields, fields_num);
+                       handle_listval (fhout, buffer);
                }
                else if (strcasecmp (fields[0], "putnotif") == 0)
                {
-                       handle_putnotif (fhout, fields, fields_num);
+                       handle_putnotif (fhout, buffer);
                }
                else if (strcasecmp (fields[0], "flush") == 0)
                {
@@ -270,7 +284,7 @@ static void *us_handle_client (void *arg)
                }
        } /* while (fgets) */
 
-       DEBUG ("Exiting..");
+       DEBUG ("unixsock plugin: us_handle_client: Exiting..");
        fclose (fhin);
        fclose (fhout);
 
@@ -278,7 +292,7 @@ static void *us_handle_client (void *arg)
        return ((void *) 0);
 } /* void *us_handle_client */
 
-static void *us_server_thread (void *arg)
+static void *us_server_thread (void __attribute__((unused)) *arg)
 {
        int  status;
        int *remote_fd;
@@ -383,8 +397,15 @@ static int us_config (const char *key, const char *val)
 
 static int us_init (void)
 {
+       static int have_init = 0;
+
        int status;
 
+       /* Initialize only once. */
+       if (have_init != 0)
+               return (0);
+       have_init = 1;
+
        loop = 1;
 
        status = pthread_create (&listen_thread, NULL, us_server_thread, NULL);