perf probe: Check the orphaned -x option

To avoid probing in unintended binary, the orphaned -x option must be
checked and warned.

Without this patch, following command sets up the probe in the kernel.

  -----
  # perf probe -a strcpy -x ./perf
  Added new event:
    probe:strcpy         (on strcpy)

  You can now use it in all perf tools, such as:

          perf record -e probe:strcpy -aR sleep 1
  -----

But in this case, it seems that the user may want to probe in the perf
binary. With this patch, perf-probe correctly handles the orphaned -x.

  -----
  # perf probe -a strcpy -x ./perf
    Error: -x/-m must follow the probe definitions.
  ...
  -----

Reported-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150401102541.17137.75477.stgit@localhost.localdomain
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 2df23e177da5..f7b1af67e9f6 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -56,6 +56,7 @@ static struct {
         bool mod_events;
         bool uprobes;
         bool quiet;
+        bool target_used;
         int nevents;
         struct perf_probe_event events[MAX_PROBES];
         struct strlist *dellist;
@@ -82,6 +83,7 @@ static int parse_probe_event(const char *str)
                 pev->target = strdup(params.target);
                 if (!pev->target)
                         return -ENOMEM;
+                params.target_used = true;
         }
 
         /* Parse a perf-probe command into event */
@@ -107,6 +109,7 @@ static int set_target(const char *ptr)
                 params.target = strdup(ptr);
                 if (!params.target)
                         return -ENOMEM;
+                params.target_used = false;
 
                 found = 1;
                 buf = ptr + (strlen(ptr) - 3);
@@ -207,6 +210,7 @@ static int opt_set_target(const struct option *opt, const char *str,
                 }
                 free(params.target);
                 params.target = tmp;
+                params.target_used = false;
                 ret = 0;
         }
 
@@ -491,6 +495,12 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
         }
 
         if (params.nevents) {
+                /* Ensure the last given target is used */
+                if (params.target && !params.target_used) {
+                        pr_warning("  Error: -x/-m must follow the probe definitions.\n");
+                        usage_with_options(probe_usage, options);
+                }
+
                 ret = add_perf_probe_events(params.events, params.nevents,
                                             params.max_probe_points,
                                             params.force_add);