From 2771984c7f5e6cab812e86ec152da4fb5f6df908 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 24 Mar 2015 09:57:52 -0400 Subject: [PATCH] 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 Cc: Andrew Morton Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20150324135923.001103479@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo --- 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 bdb1dd6..bc22722 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 84e554f..8bd7c6a 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, -- 2.7.4