Check setvbuf return value

[blktrace.git] / blktrace.c

diff --git a/blktrace.c b/blktrace.c
index 18c51579d2f708f9746945384f9fa20a104cd40d..49cfca61352ddca5233f669e76edb1bea54f84e2 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -460,8 +460,8 @@ static char usage_str[] = "\n\n" \
        "\t-w Stop after defined time, in seconds\n" \
        "\t-a Only trace specified actions. See documentation\n" \
        "\t-A Give trace mask as a single value. See documentation\n" \
-       "\t-b Sub buffer size in KiB\n" \
-       "\t-n Number of sub buffers\n" \
+       "\t-b Sub buffer size in KiB (default 512)\n" \
+       "\t-n Number of sub buffers (default 4)\n" \
        "\t-l Run in network listen mode (blktrace server)\n" \
        "\t-h Run in network client mode, connecting to the given host\n" \
        "\t-p Network port to use (default 8462)\n" \
@@ -1330,7 +1330,7 @@ static struct trace_buf *tb_combine(struct trace_buf *prev,
                 * the whole structures, as the other fields
                 * are "static".
                 */
-               prev = realloc(prev->buf, sizeof(*prev) + tot_len);
+               prev = realloc(prev, sizeof(*prev) + tot_len);
                prev->buf = (void *)(prev + 1);
        }
 
@@ -2155,12 +2155,17 @@ static int handle_args(int argc, char *argv[])
                return 1;
        }
 
-       if (statfs(debugfs_path, &st) < 0 || st.f_type != (long)DEBUGFS_TYPE) {
+       if (statfs(debugfs_path, &st) < 0) {
                fprintf(stderr, "Invalid debug path %s: %d/%s\n",
                        debugfs_path, errno, strerror(errno));
                return 1;
        }
 
+       if (st.f_type != (long)DEBUGFS_TYPE) {
+               fprintf(stderr, "Debugfs is not mounted at %s\n", debugfs_path);
+               return 1;
+       }
+
        if (act_mask_tmp != 0)
                act_mask = act_mask_tmp;
 
@@ -2178,7 +2183,10 @@ static int handle_args(int argc, char *argv[])
                piped_output = 1;
                handle_pfds = handle_pfds_entries;
                pfp = stdout;
-               setvbuf(pfp, NULL, _IONBF, 0);
+               if (setvbuf(pfp, NULL, _IONBF, 0)) {
+                       perror("setvbuf stdout");
+                       return 1;
+               }
        } else
                handle_pfds = handle_pfds_file;
        return 0;