From: "Steven Rostedt (Red Hat)" <rost...@goodmis.org>
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 <rost...@goodmis.org>
---
tools/lib/traceevent/event-parse.c | 90 ++++++++++++++++++++++++++++++++++++++
tools/lib/traceevent/event-parse.h | 5 +++
2 files changed, 95 insertions(+)
diff --git a/tools/lib/traceevent/event-parse.c
b/tools/lib/traceevent/event-parse.c
index 5795d9451063..8cc3e894ff46 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -4951,6 +4951,96 @@ 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,
--
2.1.4
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