kprobe-tracer: Check new event/group name

Check new event/group name is same syntax as a C symbol. In other
words, checking the name is as like as other tracepoint events.

This can prevent user to create an event with useless name (e.g.
foo|bar, foo*bar).

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20091216222408.14459.68790.stgit@dhcp-100-2-132.bos.redhat.com>
[ v2: minor cleanups ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 6 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ecab06547a5..375f81a568dc 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -282,6 +282,18 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
                                 struct pt_regs *regs);
 
+/* Check the name is good for event/group */
+static int check_event_name(const char *name)
+{
+        if (!isalpha(*name) && *name != '_')
+                return 0;
+        while (*++name != '\0') {
+                if (!isalpha(*name) && !isdigit(*name) && *name != '_')
+                        return 0;
+        }
+        return 1;
+}
+
 /*
  * Allocate new trace_probe and initialize it (including kprobes).
  */
@@ -293,10 +305,11 @@ static struct trace_probe *alloc_trace_probe(const char *group,
                                              int nargs, int is_return)
 {
         struct trace_probe *tp;
+        int ret = -ENOMEM;
 
         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
         if (!tp)
-                return ERR_PTR(-ENOMEM);
+                return ERR_PTR(ret);
 
         if (symbol) {
                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
@@ -312,14 +325,20 @@ static struct trace_probe *alloc_trace_probe(const char *group,
         else
                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 
-        if (!event)
+        if (!event || !check_event_name(event)) {
+                ret = -EINVAL;
                 goto error;
+        }
+
         tp->call.name = kstrdup(event, GFP_KERNEL);
         if (!tp->call.name)
                 goto error;
 
-        if (!group)
+        if (!group || !check_event_name(group)) {
+                ret = -EINVAL;
                 goto error;
+        }
+
         tp->call.system = kstrdup(group, GFP_KERNEL);
         if (!tp->call.system)
                 goto error;
@@ -330,7 +349,7 @@ error:
         kfree(tp->call.name);
         kfree(tp->symbol);
         kfree(tp);
-        return ERR_PTR(-ENOMEM);
+        return ERR_PTR(ret);
 }
 
 static void free_probe_arg(struct probe_arg *arg)
@@ -695,10 +714,10 @@ static int create_trace_probe(int argc, char **argv)
         if (!event) {
                 /* Make a new event name */
                 if (symbol)
-                        snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
+                        snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
                                  is_return ? 'r' : 'p', symbol, offset);
                 else
-                        snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
+                        snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
                                  is_return ? 'r' : 'p', addr);
                 event = buf;
         }