Commit 60f1d5e3 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt
Browse files

ftrace: Support full glob matching 

Use glob_match() to support flexible glob wildcards (*,?)
and character classes ([) for ftrace.
Since the full glob matching is slower than the current
partial matching routines(*pat, pat*, *pat*), this leaves
those routines and just add MATCH_GLOB for complex glob
expression.

e.g.
----
[root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
[root@localhost tracing]# cat set_ftrace_filter
sched_free_group
sched_change_group
sched_create_group
sched_online_group
sched_destroy_group
sched_offline_group
[root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
[root@localhost tracing]# head set_ftrace_filter
sys_arch_prctl
sys_rt_sigreturn
sys_ioperm
SyS_iopl
sys_modify_ldt
SyS_mmap
SyS_set_thread_area
SyS_get_thread_area
SyS_set_tid_address
sys_fork
----

Link: http://lkml.kernel.org/r/147566869501.29136.6462645009894738056.stgit@devbox



Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 546fece4

Documentation/trace/events.txt

+3 −6
Original line number Diff line number Diff line
@@ -189,16 +189,13 @@ And for string fields they are: 


==, !=, ~



The glob (~) only accepts a wild card character (*) at the start and or

end of the string. For example:

The glob (~) accepts a wild card character (*,?) and character classes

([). For example:



  prev_comm ~ "*sh"

  prev_comm ~ "sh*"

  prev_comm ~ "*sh*"



But does not allow for it to be within the string:



  prev_comm ~ "ba*sh"   <-- is invalid

  prev_comm ~ "ba*sh"



5.2 Setting filters

-------------------

Documentation/trace/ftrace.txt

+3 −6
Original line number Diff line number Diff line
@@ -2218,16 +2218,13 @@ hrtimer_interrupt 
sys_nanosleep





Perhaps this is not enough. The filters also allow simple wild

cards. Only the following are currently available

Perhaps this is not enough. The filters also allow glob(7) matching.



  <match>*  - will match functions that begin with <match>

  *<match>  - will match functions that end with <match>

  *<match>* - will match functions that have <match> in it



These are the only wild cards which are supported.



  <match>*<match> will not work.

  <match1>*<match2> - will match functions that begin with

                      <match1> and end with <match2>



Note: It is better to use quotes to enclose the wild cards,

      otherwise the shell may expand the parameters into names

kernel/trace/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ config FTRACE_NMI_ENTER 


config EVENT_TRACING

	select CONTEXT_SWITCH_TRACER

        select GLOB

	bool



config CONTEXT_SWITCH_TRACER
@@ -133,6 +134,7 @@ config FUNCTION_TRACER 
	select KALLSYMS

	select GENERIC_TRACER

	select CONTEXT_SWITCH_TRACER

        select GLOB

	help

	  Enable the kernel to trace every kernel function. This is done

	  by using a compiler feature to insert a small, 5-byte No-Operation

kernel/trace/ftrace.c

+4 −0
Original line number Diff line number Diff line
@@ -3511,6 +3511,10 @@ static int ftrace_match(char *str, struct ftrace_glob *g) 
		    memcmp(str + slen - g->len, g->search, g->len) == 0)

			matched = 1;

		break;

	case MATCH_GLOB:

		if (glob_match(g->search, str))

			matched = 1;

		break;

	}



	return matched;

kernel/trace/trace.c

+1 −1
Original line number Diff line number Diff line
@@ -4065,7 +4065,7 @@ static const char readme_msg[] = 
	"\n  available_filter_functions - list of functions that can be filtered on\n"

	"  set_ftrace_filter\t- echo function name in here to only trace these\n"

	"\t\t\t  functions\n"

	"\t     accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"

	"\t     accepts: func_full_name or glob-matching-pattern\n"

	"\t     modules: Can select a group via module\n"

	"\t      Format: :mod:<module-name>\n"

	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"

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