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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-03-24 16:57:52 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-03-24 18:19:06 +0300
commit2771984c7f5e6cab812e86ec152da4fb5f6df908 (patch)
treed64fc4817823894a6a069707812f16bd197c72fa /tools/lib
parent55426296963c678650e26fc5e61ea75a5598ef5a (diff)
downloadlinux-2771984c7f5e6cab812e86ec152da4fb5f6df908.tar.xz
tools lib traceevent: Add pevent_data_pid_from_comm()
There is a pevent_data_comm_from_pid() that returns the cmdline stored for a given pid in order for users to map pids to comms, but there's no method to convert a comm back to a pid. This is useful for filters that specify a comm instead of a PID (it's faster than searching each individual event). Add a way to retrieve a comm from a pid. Since there can be more than one pid associated to a comm, it returns a data structure that lets the user iterate over all the saved comms for a given pid. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20150324135923.001103479@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/traceevent/event-parse.c90
-rw-r--r--tools/lib/traceevent/event-parse.h5
2 files changed, 95 insertions, 0 deletions
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index bdb1dd618e0e..bc227225c7f4 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -4954,6 +4954,96 @@ const char *pevent_data_comm_from_pid(struct pevent *pevent, int pid)
return comm;
}
+static struct cmdline *
+pid_from_cmdlist(struct pevent *pevent, const char *comm, struct cmdline *next)
+{
+ struct cmdline_list *cmdlist = (struct cmdline_list *)next;
+
+ if (cmdlist)
+ cmdlist = cmdlist->next;
+ else
+ cmdlist = pevent->cmdlist;
+
+ while (cmdlist && strcmp(cmdlist->comm, comm) != 0)
+ cmdlist = cmdlist->next;
+
+ return (struct cmdline *)cmdlist;
+}
+
+/**
+ * pevent_data_pid_from_comm - return the pid from a given comm
+ * @pevent: a handle to the pevent
+ * @comm: the cmdline to find the pid from
+ * @next: the cmdline structure to find the next comm
+ *
+ * This returns the cmdline structure that holds a pid for a given
+ * comm, or NULL if none found. As there may be more than one pid for
+ * a given comm, the result of this call can be passed back into
+ * a recurring call in the @next paramater, and then it will find the
+ * next pid.
+ * Also, it does a linear seach, so it may be slow.
+ */
+struct cmdline *pevent_data_pid_from_comm(struct pevent *pevent, const char *comm,
+ struct cmdline *next)
+{
+ struct cmdline *cmdline;
+
+ /*
+ * If the cmdlines have not been converted yet, then use
+ * the list.
+ */
+ if (!pevent->cmdlines)
+ return pid_from_cmdlist(pevent, comm, next);
+
+ if (next) {
+ /*
+ * The next pointer could have been still from
+ * a previous call before cmdlines were created
+ */
+ if (next < pevent->cmdlines ||
+ next >= pevent->cmdlines + pevent->cmdline_count)
+ next = NULL;
+ else
+ cmdline = next++;
+ }
+
+ if (!next)
+ cmdline = pevent->cmdlines;
+
+ while (cmdline < pevent->cmdlines + pevent->cmdline_count) {
+ if (strcmp(cmdline->comm, comm) == 0)
+ return cmdline;
+ cmdline++;
+ }
+ return NULL;
+}
+
+/**
+ * pevent_cmdline_pid - return the pid associated to a given cmdline
+ * @cmdline: The cmdline structure to get the pid from
+ *
+ * Returns the pid for a give cmdline. If @cmdline is NULL, then
+ * -1 is returned.
+ */
+int pevent_cmdline_pid(struct pevent *pevent, struct cmdline *cmdline)
+{
+ struct cmdline_list *cmdlist = (struct cmdline_list *)cmdline;
+
+ if (!cmdline)
+ return -1;
+
+ /*
+ * If cmdlines have not been created yet, or cmdline is
+ * not part of the array, then treat it as a cmdlist instead.
+ */
+ if (!pevent->cmdlines ||
+ cmdline < pevent->cmdlines ||
+ cmdline >= pevent->cmdlines + pevent->cmdline_count)
+ return cmdlist->pid;
+
+ return cmdline->pid;
+}
+
/**
* pevent_data_comm_from_pid - parse the data into the print format
* @s: the trace_seq to write to
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 84e554f84574..8bd7c6a4cbd7 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -678,6 +678,11 @@ int pevent_data_type(struct pevent *pevent, struct pevent_record *rec);
struct event_format *pevent_data_event_from_type(struct pevent *pevent, int type);
int pevent_data_pid(struct pevent *pevent, struct pevent_record *rec);
const char *pevent_data_comm_from_pid(struct pevent *pevent, int pid);
+struct cmdline;
+struct cmdline *pevent_data_pid_from_comm(struct pevent *pevent, const char *comm,
+ struct cmdline *next);
+int pevent_cmdline_pid(struct pevent *pevent, struct cmdline *cmdline);
+
void pevent_event_info(struct trace_seq *s, struct event_format *event,
struct pevent_record *record);
int pevent_strerror(struct pevent *pevent, enum pevent_errno errnum,