tracing/syscalls: Add filtering support

Add filtering support for syscall events:

 # echo 'mode == 0666' > events/syscalls/sys_enter_open
 # echo 'ret == 0' > events/syscalls/sys_exit_open
 # echo 1 > events/syscalls/sys_enter_open
 # echo 1 > events/syscalls/sys_exit_open
 # cat trace
 ...
   modprobe-3084 [001] 117.463140: sys_open(filename: 917d3e8, flags: 0, mode: 1b6)
   modprobe-3084 [001] 117.463176: sys_open -> 0x0
       less-3086 [001] 117.510455: sys_open(filename: 9c6bdb8, flags: 8000, mode: 1b6)
   sendmail-2574 [001] 122.145840: sys_open(filename: b807a365, flags: 0, mode: 1b6)
 ...

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A8BAFCB.1040006@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 427cbae47f8483c755a2cd0b661aac3bca71f44c..df5b085c415068bac6bf099a9317a274c4b11731 100644 (file)
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -140,8 +140,9 @@ extern int filter_current_check_discard(struct ftrace_event_call *call,
                                        void *rec,
                                        struct ring_buffer_event *event);
 
-extern int trace_define_field(struct ftrace_event_call *call, char *type,
-                             char *name, int offset, int size, int is_signed);
+extern int trace_define_field(struct ftrace_event_call *call,
+                             const char *type, const char *name,
+                             int offset, int size, int is_signed);
 extern int trace_define_common_fields(struct ftrace_event_call *call);
 
 #define is_signed_type(type)   (((type)(-1)) < 0)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 8d57f77794eed30fabdeac6f364286f7f8626750..f124c899555529034fae28f1b5d8ad4481547f69 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -190,6 +190,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
                .event                  = &event_syscall_enter,         \
                .raw_init               = init_enter_##sname,           \
                .show_format            = syscall_enter_format,         \
+               .define_fields          = syscall_enter_define_fields,  \
                .regfunc                = reg_event_syscall_enter,      \
                .unregfunc              = unreg_event_syscall_enter,    \
                .data                   = "sys"#sname,                  \
@@ -226,6 +227,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
                .event                  = &event_syscall_exit,          \
                .raw_init               = init_exit_##sname,            \
                .show_format            = syscall_exit_format,          \
+               .define_fields          = syscall_exit_define_fields,   \
                .regfunc                = reg_event_syscall_exit,       \
                .unregfunc              = unreg_event_syscall_exit,     \
                .data                   = "sys"#sname,                  \
@@ -233,6 +235,8 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
        }
 
 #define SYSCALL_METADATA(sname, nb)                            \
+       SYSCALL_TRACE_ENTER_EVENT(sname);                       \
+       SYSCALL_TRACE_EXIT_EVENT(sname);                        \
        static const struct syscall_metadata __used             \
          __attribute__((__aligned__(4)))                       \
          __attribute__((section("__syscalls_metadata")))       \
@@ -241,20 +245,22 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
                .nb_args        = nb,                           \
                .types          = types_##sname,                \
                .args           = args_##sname,                 \
-       };                                                      \
-       SYSCALL_TRACE_ENTER_EVENT(sname);                       \
-       SYSCALL_TRACE_EXIT_EVENT(sname);
+               .enter_event    = &event_enter_##sname,         \
+               .exit_event     = &event_exit_##sname,          \
+       };
 
 #define SYSCALL_DEFINE0(sname)                                 \
+       SYSCALL_TRACE_ENTER_EVENT(_##sname);                    \
+       SYSCALL_TRACE_EXIT_EVENT(_##sname);                     \
        static const struct syscall_metadata __used             \
          __attribute__((__aligned__(4)))                       \
          __attribute__((section("__syscalls_metadata")))       \
          __syscall_meta_##sname = {                            \
                .name           = "sys_"#sname,                 \
                .nb_args        = 0,                            \
+               .enter_event    = &event_enter__##sname,        \
+               .exit_event     = &event_exit__##sname,         \
        };                                                      \
-       SYSCALL_TRACE_ENTER_EVENT(_##sname);                    \
-       SYSCALL_TRACE_EXIT_EVENT(_##sname);                     \
        asmlinkage long sys_##sname(void)
 #else
 #define SYSCALL_DEFINE0(name)     asmlinkage long sys_##name(void)

diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 5ce85d75d31b00937770c2aefc0cc0d7c8828598..9661dd406b93b3968222bf3c8df39e4691383032 100644 (file)
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -34,6 +34,8 @@ DECLARE_TRACE_WITH_CALLBACK(syscall_exit,
  * @args: list of args as strings (args[i] matches types[i])
  * @enter_id: associated ftrace enter event id
  * @exit_id: associated ftrace exit event id
+ * @enter_event: associated syscall_enter trace event
+ * @exit_event: associated syscall_exit trace event
  */
 struct syscall_metadata {
        const char      *name;
@@ -42,6 +44,9 @@ struct syscall_metadata {
        const char      **args;
        int             enter_id;
        int             exit_id;
+
+       struct ftrace_event_call *enter_event;
+       struct ftrace_event_call *exit_event;
 };
 
 #ifdef CONFIG_FTRACE_SYSCALLS
@@ -59,6 +64,8 @@ extern int syscall_enter_format(struct ftrace_event_call *call,
                                struct trace_seq *s);
 extern int syscall_exit_format(struct ftrace_event_call *call,
                                struct trace_seq *s);
+extern int syscall_enter_define_fields(struct ftrace_event_call *call);
+extern int syscall_exit_define_fields(struct ftrace_event_call *call);
 enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags);
 enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags);
 #endif

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9c7ecfb3416f4d7ad503a89bf41395696824a997..79d352027a6194759c6477e64b5390b1a5da2822 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,8 +27,8 @@ DEFINE_MUTEX(event_mutex);
 
 LIST_HEAD(ftrace_events);
 
-int trace_define_field(struct ftrace_event_call *call, char *type,
-                      char *name, int offset, int size, int is_signed)
+int trace_define_field(struct ftrace_event_call *call, const char *type,
+                      const char *name, int offset, int size, int is_signed)
 {
        struct ftrace_event_field *field;
 
@@ -83,6 +83,7 @@ int trace_define_common_fields(struct ftrace_event_call *call)
 
        return ret;
 }
+EXPORT_SYMBOL_GPL(trace_define_common_fields);
 
 #ifdef CONFIG_MODULES
 

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 7336b6c265d7380ed40af8b7132990dbee935ebf..28e4dae4af21e6530b8f3403867015eec477c64b 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -165,6 +165,49 @@ int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
        return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n");
 }
 
+int syscall_enter_define_fields(struct ftrace_event_call *call)
+{
+       struct syscall_trace_enter trace;
+       struct syscall_metadata *meta;
+       int ret;
+       int nr;
+       int i;
+       int offset = offsetof(typeof(trace), args);
+
+       nr = syscall_name_to_nr(call->data);
+       meta = syscall_nr_to_meta(nr);
+
+       if (!meta)
+               return 0;
+
+       ret = trace_define_common_fields(call);
+       if (ret)
+               return ret;
+
+       for (i = 0; i < meta->nb_args; i++) {
+               ret = trace_define_field(call, meta->types[i],
+                                        meta->args[i], offset,
+                                        sizeof(unsigned long), 0);
+               offset += sizeof(unsigned long);
+       }
+
+       return ret;
+}
+
+int syscall_exit_define_fields(struct ftrace_event_call *call)
+{
+       struct syscall_trace_exit trace;
+       int ret;
+
+       ret = trace_define_common_fields(call);
+       if (ret)
+               return ret;
+
+       ret = trace_define_field(call, SYSCALL_FIELD(unsigned long, ret), 0);
+
+       return ret;
+}
+
 void ftrace_syscall_enter(struct pt_regs *regs, long id)
 {
        struct syscall_trace_enter *entry;
@@ -192,8 +235,8 @@ void ftrace_syscall_enter(struct pt_regs *regs, long id)
        entry->nr = syscall_nr;
        syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
 
-       trace_current_buffer_unlock_commit(event, 0, 0);
-       trace_wake_up();
+       if (!filter_current_check_discard(sys_data->enter_event, entry, event))
+               trace_current_buffer_unlock_commit(event, 0, 0);
 }
 
 void ftrace_syscall_exit(struct pt_regs *regs, long ret)
@@ -220,8 +263,8 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret)
        entry->nr = syscall_nr;
        entry->ret = syscall_get_return_value(current, regs);
 
-       trace_current_buffer_unlock_commit(event, 0, 0);
-       trace_wake_up();
+       if (!filter_current_check_discard(sys_data->exit_event, entry, event))
+               trace_current_buffer_unlock_commit(event, 0, 0);
 }
 
 int reg_event_syscall_enter(void *ptr)