6 files changed, 110 insertions, 63 deletions

diff --git a/tools/lib/traceevent/event-parse-api.c b/tools/lib/traceevent/event-parse-api.c
index 8b31c0e00ba3..d463761a58f4 100644
--- a/tools/lib/traceevent/event-parse-api.c
+++ b/tools/lib/traceevent/event-parse-api.c
@@ -194,13 +194,13 @@ void tep_set_page_size(struct tep_handle *pevent, int _page_size)
 }
 
 /**
- * tep_is_file_bigendian - get if the file is in big endian order
+ * tep_file_bigendian - get if the file is in big endian order
  * @pevent: a handle to the tep_handle
  *
  * This returns if the file is in big endian order
  * If @pevent is NULL, 0 is returned.
  */
-int tep_is_file_bigendian(struct tep_handle *pevent)
+int tep_file_bigendian(struct tep_handle *pevent)
 {
         if(pevent)
                 return pevent->file_bigendian;
diff --git a/tools/lib/traceevent/event-parse-local.h b/tools/lib/traceevent/event-parse-local.h
index 9a092dd4a86d..35833ee32d6c 100644
--- a/tools/lib/traceevent/event-parse-local.h
+++ b/tools/lib/traceevent/event-parse-local.h
@@ -7,7 +7,7 @@
 #ifndef _PARSE_EVENTS_INT_H
 #define _PARSE_EVENTS_INT_H
 
-struct cmdline;
+struct tep_cmdline;
 struct cmdline_list;
 struct func_map;
 struct func_list;
@@ -36,7 +36,7 @@ struct tep_handle {
         int long_size;
         int page_size;
 
-        struct cmdline *cmdlines;
+        struct tep_cmdline *cmdlines;
         struct cmdline_list *cmdlist;
         int cmdline_count;
 
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 69a96e39f0ab..abd4fa5d3088 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -124,15 +124,15 @@ struct tep_print_arg *alloc_arg(void)
         return calloc(1, sizeof(struct tep_print_arg));
 }
 
-struct cmdline {
+struct tep_cmdline {
         char *comm;
         int pid;
 };
 
 static int cmdline_cmp(const void *a, const void *b)
 {
-        const struct cmdline *ca = a;
-        const struct cmdline *cb = b;
+        const struct tep_cmdline *ca = a;
+        const struct tep_cmdline *cb = b;
 
         if (ca->pid < cb->pid)
                 return -1;
@@ -152,7 +152,7 @@ static int cmdline_init(struct tep_handle *pevent)
 {
         struct cmdline_list *cmdlist = pevent->cmdlist;
         struct cmdline_list *item;
-        struct cmdline *cmdlines;
+        struct tep_cmdline *cmdlines;
         int i;
 
         cmdlines = malloc(sizeof(*cmdlines) * pevent->cmdline_count);
@@ -179,8 +179,8 @@ static int cmdline_init(struct tep_handle *pevent)
 
 static const char *find_cmdline(struct tep_handle *pevent, int pid)
 {
-        const struct cmdline *comm;
-        struct cmdline key;
+        const struct tep_cmdline *comm;
+        struct tep_cmdline key;
 
         if (!pid)
                 return "<idle>";
@@ -208,8 +208,8 @@ static const char *find_cmdline(struct tep_handle *pevent, int pid)
  */
 int tep_pid_is_registered(struct tep_handle *pevent, int pid)
 {
-        const struct cmdline *comm;
-        struct cmdline key;
+        const struct tep_cmdline *comm;
+        struct tep_cmdline key;
 
         if (!pid)
                 return 1;
@@ -232,11 +232,13 @@ int tep_pid_is_registered(struct tep_handle *pevent, int pid)
  * we must add this pid. This is much slower than when cmdlines
  * are added before the array is initialized.
  */
-static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid)
+static int add_new_comm(struct tep_handle *pevent,
+                        const char *comm, int pid, bool override)
 {
-        struct cmdline *cmdlines = pevent->cmdlines;
-        const struct cmdline *cmdline;
-        struct cmdline key;
+        struct tep_cmdline *cmdlines = pevent->cmdlines;
+        struct tep_cmdline *cmdline;
+        struct tep_cmdline key;
+        char *new_comm;
 
         if (!pid)
                 return 0;
@@ -247,8 +249,19 @@ static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid)
         cmdline = bsearch(&key, pevent->cmdlines, pevent->cmdline_count,
                        sizeof(*pevent->cmdlines), cmdline_cmp);
         if (cmdline) {
-                errno = EEXIST;
-                return -1;
+                if (!override) {
+                        errno = EEXIST;
+                        return -1;
+                }
+                new_comm = strdup(comm);
+                if (!new_comm) {
+                        errno = ENOMEM;
+                        return -1;
+                }
+                free(cmdline->comm);
+                cmdline->comm = new_comm;
+
+                return 0;
         }
 
         cmdlines = realloc(cmdlines, sizeof(*cmdlines) * (pevent->cmdline_count + 1));
@@ -275,21 +288,13 @@ static int add_new_comm(struct tep_handle *pevent, const char *comm, int pid)
         return 0;
 }
 
-/**
- * tep_register_comm - register a pid / comm mapping
- * @pevent: handle for the pevent
- * @comm: the command line to register
- * @pid: the pid to map the command line to
- *
- * This adds a mapping to search for command line names with
- * a given pid. The comm is duplicated.
- */
-int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid)
+static int _tep_register_comm(struct tep_handle *pevent,
+                              const char *comm, int pid, bool override)
 {
         struct cmdline_list *item;
 
         if (pevent->cmdlines)
-                return add_new_comm(pevent, comm, pid);
+                return add_new_comm(pevent, comm, pid, override);
 
         item = malloc(sizeof(*item));
         if (!item)
@@ -312,6 +317,40 @@ int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid)
         return 0;
 }
 
+/**
+ * tep_register_comm - register a pid / comm mapping
+ * @pevent: handle for the pevent
+ * @comm: the command line to register
+ * @pid: the pid to map the command line to
+ *
+ * This adds a mapping to search for command line names with
+ * a given pid. The comm is duplicated. If a command with the same pid
+ * already exist, -1 is returned and errno is set to EEXIST
+ */
+int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid)
+{
+        return _tep_register_comm(pevent, comm, pid, false);
+}
+
+/**
+ * tep_override_comm - register a pid / comm mapping
+ * @pevent: handle for the pevent
+ * @comm: the command line to register
+ * @pid: the pid to map the command line to
+ *
+ * This adds a mapping to search for command line names with
+ * a given pid. The comm is duplicated. If a command with the same pid
+ * already exist, the command string is udapted with the new one
+ */
+int tep_override_comm(struct tep_handle *pevent, const char *comm, int pid)
+{
+        if (!pevent->cmdlines && cmdline_init(pevent)) {
+                errno = ENOMEM;
+                return -1;
+        }
+        return _tep_register_comm(pevent, comm, pid, true);
+}
+
 int tep_register_trace_clock(struct tep_handle *pevent, const char *trace_clock)
 {
         pevent->trace_clock = strdup(trace_clock);
@@ -5227,18 +5266,6 @@ int tep_data_type(struct tep_handle *pevent, struct tep_record *rec)
 }
 
 /**
- * tep_data_event_from_type - find the event by a given type
- * @pevent: a handle to the pevent
- * @type: the type of the event.
- *
- * This returns the event form a given @type;
- */
-struct tep_event *tep_data_event_from_type(struct tep_handle *pevent, int type)
-{
-        return tep_find_event(pevent, type);
-}
-
-/**
  * tep_data_pid - parse the PID from record
  * @pevent: a handle to the pevent
  * @rec: the record to parse
@@ -5292,8 +5319,8 @@ const char *tep_data_comm_from_pid(struct tep_handle *pevent, int pid)
         return comm;
 }
 
-static struct cmdline *
-pid_from_cmdlist(struct tep_handle *pevent, const char *comm, struct cmdline *next)
+static struct tep_cmdline *
+pid_from_cmdlist(struct tep_handle *pevent, const char *comm, struct tep_cmdline *next)
 {
         struct cmdline_list *cmdlist = (struct cmdline_list *)next;
 
@@ -5305,7 +5332,7 @@ pid_from_cmdlist(struct tep_handle *pevent, const char *comm, struct cmdline *ne
         while (cmdlist && strcmp(cmdlist->comm, comm) != 0)
                 cmdlist = cmdlist->next;
 
-        return (struct cmdline *)cmdlist;
+        return (struct tep_cmdline *)cmdlist;
 }
 
 /**
@@ -5321,10 +5348,10 @@ pid_from_cmdlist(struct tep_handle *pevent, const char *comm, struct cmdline *ne
  * next pid.
  * Also, it does a linear search, so it may be slow.
  */
-struct cmdline *tep_data_pid_from_comm(struct tep_handle *pevent, const char *comm,
-                                       struct cmdline *next)
+struct tep_cmdline *tep_data_pid_from_comm(struct tep_handle *pevent, const char *comm,
+                                           struct tep_cmdline *next)
 {
-        struct cmdline *cmdline;
+        struct tep_cmdline *cmdline;
 
         /*
          * If the cmdlines have not been converted yet, then use
@@ -5363,7 +5390,7 @@ struct cmdline *tep_data_pid_from_comm(struct tep_handle *pevent, const char *co
  * Returns the pid for a give cmdline. If @cmdline is NULL, then
  * -1 is returned.
  */
-int tep_cmdline_pid(struct tep_handle *pevent, struct cmdline *cmdline)
+int tep_cmdline_pid(struct tep_handle *pevent, struct tep_cmdline *cmdline)
 {
         struct cmdline_list *cmdlist = (struct cmdline_list *)cmdline;
 
@@ -6593,6 +6620,12 @@ static struct tep_event *search_event(struct tep_handle *pevent, int id,
  *
  * If @id is >= 0, then it is used to find the event.
  * else @sys_name and @event_name are used.
+ *
+ * Returns:
+ *  TEP_REGISTER_SUCCESS_OVERWRITE if an existing handler is overwritten
+ *  TEP_REGISTER_SUCCESS if a new handler is registered successfully
+ *  negative TEP_ERRNO_... in case of an error
+ *
  */
 int tep_register_event_handler(struct tep_handle *pevent, int id,
                                const char *sys_name, const char *event_name,
@@ -6610,7 +6643,7 @@ int tep_register_event_handler(struct tep_handle *pevent, int id,
 
         event->handler = func;
         event->context = context;
-        return 0;
+        return TEP_REGISTER_SUCCESS_OVERWRITE;
 
  not_found:
         /* Save for later use. */
@@ -6640,7 +6673,7 @@ int tep_register_event_handler(struct tep_handle *pevent, int id,
         pevent->handlers = handle;
         handle->context = context;
 
-        return -1;
+        return TEP_REGISTER_SUCCESS;
 }
 
 static int handle_matches(struct event_handler *handler, int id,
@@ -6723,8 +6756,10 @@ struct tep_handle *tep_alloc(void)
 {
         struct tep_handle *pevent = calloc(1, sizeof(*pevent));
 
-        if (pevent)
+        if (pevent) {
                 pevent->ref_count = 1;
+                pevent->host_bigendian = tep_host_bigendian();
+        }
 
         return pevent;
 }
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 35d37087d3c5..aec48f2aea8a 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -432,6 +432,7 @@ int tep_set_function_resolver(struct tep_handle *pevent,
                               tep_func_resolver_t *func, void *priv);
 void tep_reset_function_resolver(struct tep_handle *pevent);
 int tep_register_comm(struct tep_handle *pevent, const char *comm, int pid);
+int tep_override_comm(struct tep_handle *pevent, const char *comm, int pid);
 int tep_register_trace_clock(struct tep_handle *pevent, const char *trace_clock);
 int tep_register_function(struct tep_handle *pevent, char *name,
                           unsigned long long addr, char *mod);
@@ -484,6 +485,11 @@ int tep_print_func_field(struct trace_seq *s, const char *fmt,
                          struct tep_event *event, const char *name,
                          struct tep_record *record, int err);
 
+enum tep_reg_handler {
+        TEP_REGISTER_SUCCESS = 0,
+        TEP_REGISTER_SUCCESS_OVERWRITE,
+};
+
 int tep_register_event_handler(struct tep_handle *pevent, int id,
                                const char *sys_name, const char *event_name,
                                tep_event_handler_func func, void *context);
@@ -520,15 +526,14 @@ tep_find_event_by_record(struct tep_handle *pevent, struct tep_record *record);
 void tep_data_lat_fmt(struct tep_handle *pevent,
                       struct trace_seq *s, struct tep_record *record);
 int tep_data_type(struct tep_handle *pevent, struct tep_record *rec);
-struct tep_event *tep_data_event_from_type(struct tep_handle *pevent, int type);
 int tep_data_pid(struct tep_handle *pevent, struct tep_record *rec);
 int tep_data_preempt_count(struct tep_handle *pevent, struct tep_record *rec);
 int tep_data_flags(struct tep_handle *pevent, struct tep_record *rec);
 const char *tep_data_comm_from_pid(struct tep_handle *pevent, int pid);
-struct cmdline;
-struct cmdline *tep_data_pid_from_comm(struct tep_handle *pevent, const char *comm,
-                                       struct cmdline *next);
-int tep_cmdline_pid(struct tep_handle *pevent, struct cmdline *cmdline);
+struct tep_cmdline;
+struct tep_cmdline *tep_data_pid_from_comm(struct tep_handle *pevent, const char *comm,
+                                           struct tep_cmdline *next);
+int tep_cmdline_pid(struct tep_handle *pevent, struct tep_cmdline *cmdline);
 
 void tep_print_field(struct trace_seq *s, void *data,
                      struct tep_format_field *field);
@@ -553,7 +558,7 @@ int tep_get_long_size(struct tep_handle *pevent);
 void tep_set_long_size(struct tep_handle *pevent, int long_size);
 int tep_get_page_size(struct tep_handle *pevent);
 void tep_set_page_size(struct tep_handle *pevent, int _page_size);
-int tep_is_file_bigendian(struct tep_handle *pevent);
+int tep_file_bigendian(struct tep_handle *pevent);
 void tep_set_file_bigendian(struct tep_handle *pevent, enum tep_endian endian);
 int tep_is_host_bigendian(struct tep_handle *pevent);
 void tep_set_host_bigendian(struct tep_handle *pevent, enum tep_endian endian);
diff --git a/tools/lib/traceevent/plugin_kvm.c b/tools/lib/traceevent/plugin_kvm.c
index 754050eea467..64b9c25a1fd3 100644
--- a/tools/lib/traceevent/plugin_kvm.c
+++ b/tools/lib/traceevent/plugin_kvm.c
@@ -389,7 +389,7 @@ static int kvm_mmu_print_role(struct trace_seq *s, struct tep_record *record,
          * We can only use the structure if file is of the same
          * endianness.
          */
-        if (tep_is_file_bigendian(event->pevent) ==
+        if (tep_file_bigendian(event->pevent) ==
             tep_is_host_bigendian(event->pevent)) {
 
                 trace_seq_printf(s, "%u q%u%s %s%s %spae %snxe %swp%s%s%s",
diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index 8ff1d55954d1..8d5ecd2bf877 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -100,7 +100,8 @@ static void expand_buffer(struct trace_seq *s)
  * @fmt: printf format string
  *
  * It returns 0 if the trace oversizes the buffer's free
- * space, 1 otherwise.
+ * space, the number of characters printed, or a negative
+ * value in case of an error.
  *
  * The tracer may use either sequence operations or its own
  * copy to user routines. To simplify formating of a trace
@@ -129,9 +130,10 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
                 goto try_again;
         }
 
-        s->len += ret;
+        if (ret > 0)
+                s->len += ret;
 
-        return 1;
+        return ret;
 }
 
 /**
@@ -139,6 +141,10 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
  * @s: trace sequence descriptor
  * @fmt: printf format string
  *
+ * It returns 0 if the trace oversizes the buffer's free
+ * space, the number of characters printed, or a negative
+ * value in case of an error.
+ * *
  * The tracer may use either sequence operations or its own
  * copy to user routines. To simplify formating of a trace
  * trace_seq_printf is used to store strings into a special
@@ -163,9 +169,10 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
                 goto try_again;
         }
 
-        s->len += ret;
+        if (ret > 0)
+                s->len += ret;
 
-        return len;
+        return ret;
 }
 
 /**