Add NULL pointer check

[lttng-tools.git] / liblttngctl / lttngctl.c

diff --git a/liblttngctl/lttngctl.c b/liblttngctl/lttngctl.c
index 827de137e550ef33de57de09f0d823079d2fd513..b64ace2e6d80de0ce085791f698604e53f8eb523 100644 (file)
--- a/liblttngctl/lttngctl.c
+++ b/liblttngctl/lttngctl.c
@@ -21,18 +21,17 @@
  */
 
 #define _GNU_SOURCE
-#include <errno.h>
 #include <grp.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
-#include <lttng/lttng.h>
-
 #include <lttng-sessiond-comm.h>
-#include "lttngerr.h"
-#include "lttng-share.h"
+#include <lttng-share.h>
+#include <lttng/lttng.h>
+#include <lttngerr.h>
 
 /* Socket to session daemon for communication */
 static int sessiond_socket;
@@ -125,7 +124,7 @@ end:
 /*
  *  Check if the specified group name exist.
  *
- *  If yes return 0, else return -1.
+ *  If yes return 1, else return -1.
  */
 static int check_tracing_group(const char *grp_name)
 {
@@ -161,7 +160,7 @@ static int check_tracing_group(const char *grp_name)
 
        for (i = 0; i < grp_list_size; i++) {
                if (grp_list[i] == grp_tracing->gr_gid) {
-                       ret = 0;
+                       ret = 1;
                        break;
                }
        }
@@ -174,25 +173,79 @@ end:
 }
 
 /*
- *  Set sessiond socket path by putting it in the global sessiond_sock_path
- *  variable.
+ * Try connect to session daemon with sock_path.
+ *
+ * Return 0 on success, else -1
+ */
+static int try_connect_sessiond(const char *sock_path)
+{
+       int ret;
+
+       /* If socket exist, we check if the daemon listens for connect. */
+       ret = access(sock_path, F_OK);
+       if (ret < 0) {
+               /* Not alive */
+               return -1;
+       }
+
+       ret = lttcomm_connect_unix_sock(sock_path);
+       if (ret < 0) {
+               /* Not alive */
+               return -1;
+       }
+
+       ret = lttcomm_close_unix_sock(ret);
+       if (ret < 0) {
+               perror("lttcomm_close_unix_sock");
+       }
+
+       return 0;
+}
+
+/*
+ * Set sessiond socket path by putting it in the global sessiond_sock_path
+ * variable.
  */
 static int set_session_daemon_path(void)
 {
        int ret;
+       int in_tgroup = 0;      /* In tracing group */
+       uid_t uid;
 
-       /* Are we in the tracing group ? */
-       ret = check_tracing_group(tracing_group);
-       if (ret < 0 && getuid() != 0) {
+       uid = getuid();
+
+       if (uid != 0) {
+               /* Are we in the tracing group ? */
+               in_tgroup = check_tracing_group(tracing_group);
+       }
+
+       if (uid == 0) {
+               /* Root */
+               copy_string(sessiond_sock_path,
+                               DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
+                               sizeof(sessiond_sock_path));
+       } else if (in_tgroup) {
+               /* Tracing group */
+               copy_string(sessiond_sock_path,
+                               DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
+                               sizeof(sessiond_sock_path));
+
+               ret = try_connect_sessiond(sessiond_sock_path);
+               if (ret < 0) {
+                       /* Global session daemon not available */
+                       if (snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
+                                               DEFAULT_HOME_CLIENT_UNIX_SOCK,
+                                               getenv("HOME")) < 0) {
+                               return -ENOMEM;
+                       }
+               }
+       } else {
+               /* Not in tracing group and not root, default */
                if (snprintf(sessiond_sock_path, PATH_MAX,
                                        DEFAULT_HOME_CLIENT_UNIX_SOCK,
                                        getenv("HOME")) < 0) {
                        return -ENOMEM;
                }
-       } else {
-               copy_string(sessiond_sock_path,
-                               DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
-                               PATH_MAX);
        }
 
        return 0;
@@ -290,6 +343,16 @@ static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
                goto end;
        }
 
+       /*
+        * Extra protection not to dereference a NULL pointer. If buf is NULL at
+        * this point, an error is returned and data is freed.
+        */
+       if (buf == NULL) {
+               ret = -1;
+               free(data);
+               goto end;
+       }
+
        *buf = data;
        ret = size;
 
@@ -333,6 +396,24 @@ void lttng_destroy_handle(struct lttng_handle *handle)
        }
 }
 
+/*
+ * Register an outside consumer.
+ */
+int lttng_register_consumer(struct lttng_handle *handle,
+               const char *socket_path)
+{
+       struct lttcomm_session_msg lsm;
+
+       lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
+       copy_string(lsm.session.name, handle->session_name,
+                       sizeof(lsm.session.name));
+       copy_lttng_domain(&lsm.domain, &handle->domain);
+
+       copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
+
+       return ask_sessiond(&lsm, NULL);
+}
+
 /*
  *  Start tracing for all trace of the session.
  */
@@ -730,11 +811,10 @@ int lttng_calibrate(struct lttng_handle *handle,
 }
 
 /*
- *  lttng_check_session_daemon
+ * Check if session daemon is alive.
  *
- *  Yes, return 1
- *  No, return 0
- *  Error, return negative value
+ * Return 1 if alive or 0 if not.
+ * On error return -1
  */
 int lttng_session_daemon_alive(void)
 {
@@ -746,21 +826,16 @@ int lttng_session_daemon_alive(void)
                return ret;
        }
 
-       /* If socket exist, we check if the daemon listens to connect. */
-       ret = access(sessiond_sock_path, F_OK);
-       if (ret < 0) {
-               /* Not alive */
-               return 0;
+       if (strlen(sessiond_sock_path) == 0) {
+               /* No socket path set. Weird error */
+               return -1;
        }
 
-       ret = lttcomm_connect_unix_sock(sessiond_sock_path);
+       ret = try_connect_sessiond(sessiond_sock_path);
        if (ret < 0) {
                /* Not alive */
                return 0;
        }
-       ret = lttcomm_close_unix_sock(ret);
-       if (ret < 0)
-               perror("lttcomm_close_unix_sock");
 
        /* Is alive */
        return 1;