linux-stable/tools/perf/util/trace-event-parse.c
Chris Phlipot c9f23d2bc2 perf event-parse: Use fixed size string for comms
Some implementations of libc do not support the 'm' width modifier as
part of the scanf string format specifier. This can cause the parsing to
fail.  Since the parser never checks if the scanf parsing was
successesful, this can result in a crash.

Change the comm string to be allocated as a fixed size instead of
dynamically using 'm' scanf width modifier. This can be safely done
since comm size is limited to 16 bytes by TASK_COMM_LEN within the
kernel.

This change prevents perf from crashing when linked against bionic as
well as reduces the total number of heap allocations and frees invoked
while accomplishing the same task.

Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180830021950.15563-1-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-08-30 14:51:45 -03:00

256 lines
5.7 KiB
C

/*
* Copyright (C) 2009, Steven Rostedt <srostedt@redhat.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License (not later!)
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "../perf.h"
#include "debug.h"
#include "trace-event.h"
#include "sane_ctype.h"
static int get_common_field(struct scripting_context *context,
int *offset, int *size, const char *type)
{
struct tep_handle *pevent = context->pevent;
struct event_format *event;
struct format_field *field;
if (!*size) {
if (!pevent->events)
return 0;
event = pevent->events[0];
field = tep_find_common_field(event, type);
if (!field)
return 0;
*offset = field->offset;
*size = field->size;
}
return tep_read_number(pevent, context->event_data + *offset, *size);
}
int common_lock_depth(struct scripting_context *context)
{
static int offset;
static int size;
int ret;
ret = get_common_field(context, &size, &offset,
"common_lock_depth");
if (ret < 0)
return -1;
return ret;
}
int common_flags(struct scripting_context *context)
{
static int offset;
static int size;
int ret;
ret = get_common_field(context, &size, &offset,
"common_flags");
if (ret < 0)
return -1;
return ret;
}
int common_pc(struct scripting_context *context)
{
static int offset;
static int size;
int ret;
ret = get_common_field(context, &size, &offset,
"common_preempt_count");
if (ret < 0)
return -1;
return ret;
}
unsigned long long
raw_field_value(struct event_format *event, const char *name, void *data)
{
struct format_field *field;
unsigned long long val;
field = tep_find_any_field(event, name);
if (!field)
return 0ULL;
tep_read_number_field(field, data, &val);
return val;
}
unsigned long long read_size(struct event_format *event, void *ptr, int size)
{
return tep_read_number(event->pevent, ptr, size);
}
void event_format__fprintf(struct event_format *event,
int cpu, void *data, int size, FILE *fp)
{
struct tep_record record;
struct trace_seq s;
memset(&record, 0, sizeof(record));
record.cpu = cpu;
record.size = size;
record.data = data;
trace_seq_init(&s);
tep_event_info(&s, event, &record);
trace_seq_do_fprintf(&s, fp);
trace_seq_destroy(&s);
}
void event_format__print(struct event_format *event,
int cpu, void *data, int size)
{
return event_format__fprintf(event, cpu, data, size, stdout);
}
void parse_ftrace_printk(struct tep_handle *pevent,
char *file, unsigned int size __maybe_unused)
{
unsigned long long addr;
char *printk;
char *line;
char *next = NULL;
char *addr_str;
char *fmt = NULL;
line = strtok_r(file, "\n", &next);
while (line) {
addr_str = strtok_r(line, ":", &fmt);
if (!addr_str) {
pr_warning("printk format with empty entry");
break;
}
addr = strtoull(addr_str, NULL, 16);
/* fmt still has a space, skip it */
printk = strdup(fmt+1);
line = strtok_r(NULL, "\n", &next);
tep_register_print_string(pevent, printk, addr);
}
}
void parse_saved_cmdline(struct tep_handle *pevent,
char *file, unsigned int size __maybe_unused)
{
char comm[17]; /* Max comm length in the kernel is 16. */
char *line;
char *next = NULL;
int pid;
line = strtok_r(file, "\n", &next);
while (line) {
if (sscanf(line, "%d %16s", &pid, comm) == 2)
tep_register_comm(pevent, comm, pid);
line = strtok_r(NULL, "\n", &next);
}
}
int parse_ftrace_file(struct tep_handle *pevent, char *buf, unsigned long size)
{
return tep_parse_event(pevent, buf, size, "ftrace");
}
int parse_event_file(struct tep_handle *pevent,
char *buf, unsigned long size, char *sys)
{
return tep_parse_event(pevent, buf, size, sys);
}
struct event_format *trace_find_next_event(struct tep_handle *pevent,
struct event_format *event)
{
static int idx;
if (!pevent || !pevent->events)
return NULL;
if (!event) {
idx = 0;
return pevent->events[0];
}
if (idx < pevent->nr_events && event == pevent->events[idx]) {
idx++;
if (idx == pevent->nr_events)
return NULL;
return pevent->events[idx];
}
for (idx = 1; idx < pevent->nr_events; idx++) {
if (event == pevent->events[idx - 1])
return pevent->events[idx];
}
return NULL;
}
struct flag {
const char *name;
unsigned long long value;
};
static const struct flag flags[] = {
{ "HI_SOFTIRQ", 0 },
{ "TIMER_SOFTIRQ", 1 },
{ "NET_TX_SOFTIRQ", 2 },
{ "NET_RX_SOFTIRQ", 3 },
{ "BLOCK_SOFTIRQ", 4 },
{ "IRQ_POLL_SOFTIRQ", 5 },
{ "TASKLET_SOFTIRQ", 6 },
{ "SCHED_SOFTIRQ", 7 },
{ "HRTIMER_SOFTIRQ", 8 },
{ "RCU_SOFTIRQ", 9 },
{ "HRTIMER_NORESTART", 0 },
{ "HRTIMER_RESTART", 1 },
};
unsigned long long eval_flag(const char *flag)
{
int i;
/*
* Some flags in the format files do not get converted.
* If the flag is not numeric, see if it is something that
* we already know about.
*/
if (isdigit(flag[0]))
return strtoull(flag, NULL, 0);
for (i = 0; i < (int)(sizeof(flags)/sizeof(flags[0])); i++)
if (strcmp(flags[i].name, flag) == 0)
return flags[i].value;
return 0;
}