iowatcher: Add bounds checking in find_step

[blktrace.git] / iowatcher / tracers.c

diff --git a/iowatcher/tracers.c b/iowatcher/tracers.c
index a995e11617e676c288aabb339f7cd0c910277ea6..d70c4a60a46910f7f5937fa99986c93982b5a872 100644 (file)
--- a/iowatcher/tracers.c
+++ b/iowatcher/tracers.c
@@ -12,7 +12,7 @@
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  *
  *  Parts of this file were imported from Jens Axboe's blktrace sources (also GPL)
  */
@@ -42,16 +42,14 @@ static char line[1024];
 static pid_t blktrace_pid = 0;
 static pid_t mpstat_pid = 0;
 
-char *blktrace_args[] = {
+char *blktrace_args[17 + MAX_DEVICES_PER_TRACE * 2] = {
        "blktrace",
-       "-d", NULL,
-       "-b", "16384",
-       "-o", "trace",
-       "-D", ".",
+       "-b", "8192",
        "-a", "queue",
        "-a", "complete",
        "-a", "issue",
        "-a", "notify",
+       "-D", ".",
        NULL,
 };
 
@@ -61,9 +59,8 @@ char *mpstat_args[] = {
        NULL,
 };
 
-#define DEVICE_INDEX 2
-#define DEST_DIR_INDEX 8
-#define TRACE_NAME_INDEX 6
+#define DEST_DIR_INDEX 12
+#define LAST_ARG 13
 
 int stop_tracer(pid_t *tracer_pid)
 {
@@ -103,18 +100,42 @@ void sig_handler_for_quit(int val)
 }
 
 
-int start_blktrace(char *device, char *trace_name, char *dest)
+int start_blktrace(char **devices, int num_devices, char *trace_name, char *dest)
 {
        pid_t pid;
        int ret;
        char **arg = blktrace_args;
-       blktrace_args[DEVICE_INDEX] = device;
+       int i;
+       int arg_index;
 
        fprintf(stderr, "running blktrace");
-       if (dest)
-               blktrace_args[DEST_DIR_INDEX] = dest;
-       if (trace_name)
-               blktrace_args[TRACE_NAME_INDEX] = trace_name;
+       if (!trace_name)
+               trace_name = "trace";
+
+       arg_index = LAST_ARG;
+       for (i = 0; i < num_devices; i++) {
+               blktrace_args[arg_index++] = "-d";
+               blktrace_args[arg_index++] = devices[i];
+       }
+
+       /*
+        * single device traces use -o and are put into
+        * the dest dir if provided
+        */
+       if (num_devices == 1) {
+               blktrace_args[arg_index++] = "-o";
+               blktrace_args[arg_index++] = trace_name;
+               if (dest)
+                       blktrace_args[DEST_DIR_INDEX] = dest;
+       } else {
+               /*
+                * multi device traces are put into a dest
+                * dir based on the trace name
+                */
+               blktrace_args[DEST_DIR_INDEX] = trace_name;
+       }
+
+       blktrace_args[arg_index] = NULL;
 
        while(*arg) {
                fprintf(stderr, " %s", *arg);