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authorWang Nan <wangnan0@huawei.com>2016-05-27 11:35:51 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-05-27 12:08:40 -0300
commit5ea5888b2fbf5b230da62b2a21c8247bebb6c9cf (patch)
treee68006e7eb3fe0bad4bfbf2f881df7d4bbbbc695 /tools
parent3dc6c1d54ff4cc9ce7e8513c286c970304cde20b (diff)
downloadlinux-5ea5888b2fbf5b230da62b2a21c8247bebb6c9cf.tar.gz
perf ctf: Convert invalid chars in a string before set value
We observed some crazy apps on Android set their comm to unprintable string. For example: # cat /proc/10607/task/*/comm tencent.qqmusic ... Binder_2 日志输出线 <-- Chinese word 'log output thread' WifiManager ... 'perf data convert' fails to convert perf.data with such string to CTF format. For example: # cat << EOF > ./badguy.c #include <sys/prctl.h> int main(int argc, char *argv[]) { prctl(PR_SET_NAME, "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf"); while(1) sleep(1); return 0; } EOF # gcc ./badguy.c # perf record -e sched:* ./a.out # perf data convert --to-ctf ./bad.ctf CTF stream 4 flush failed [ perf data convert: Converted 'perf.data' into CTF data './bad.ctf' ] [ perf data convert: Converted and wrote 0.008 MB (78 samples) ] # babeltrace ./bad.ctf/ [error] Packet size (18446744073709551615 bits) is larger than remaining file size (262144 bits). [error] Stream index creation error. [error] Open file stream error. [warning] [Context] Cannot open_trace of format ctf at path ./bad.ctf. [warning] [Context] cannot open trace "./bad.ctf" from ./bad.ctf/ for reading. [error] Cannot open any trace for reading. [error] opening trace "./bad.ctf/" for reading. [error] none of the specified trace paths could be opened. This patch converts unprintable characters to hexadecimal word. After applying this patch the above test works correctly: # ~/perf data convert --to-ctf ./good.ctf [ perf data convert: Converted 'perf.data' into CTF data './good.ctf' ] [ perf data convert: Converted and wrote 0.008 MB (78 samples) ] # babeltrace ./good.ctf .. [23:14:35.491665268] (+0.000001100) sched:sched_wakeup: { cpu_id = 4 }, { perf_ip = 0xFFFFFFFF810AEF33, perf_tid = 0, perf_pid = 0, perf_id = 5123, perf_period = 1, common_type = 270, common_flags = 45, common_preempt_count = 4, common_pid = 0, comm = "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf", pid = 1057, prio = 120, success = 1, target_cpu = 4 } [23:14:35.491666230] (+0.000000962) sched:sched_wakeup: { cpu_id = 4 }, { perf_ip = 0xFFFFFFFF810AEF33, perf_tid = 0, perf_pid = 0, perf_id = 5122, perf_period = 1, common_type = 270, common_flags = 45, common_preempt_count = 4, common_pid = 0, comm = "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf", pid = 1057, prio = 120, success = 1, target_cpu = 4 } .. Committer note: To build perf with libabeltrace, use: $ mkdir -p /tmp/build/perf $ make LIBBABELTRACE=1 LIBBABELTRACE_DIR=/usr/local O=/tmp/build/perf -C tools/perf install-bin Or equivalent (no O=, fixup LIBBABELTRACE_DIR, etc). Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1464348951-179595-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/data-convert-bt.c41
1 files changed, 39 insertions, 2 deletions
diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index bbf69d248ec5..9f53020c3269 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -204,6 +204,44 @@ static unsigned long long adjust_signedness(unsigned long long value_int, int si
return (value_int & value_mask) | ~value_mask;
}
+static int string_set_value(struct bt_ctf_field *field, const char *string)
+{
+ char *buffer = NULL;
+ size_t len = strlen(string), i, p;
+ int err;
+
+ for (i = p = 0; i < len; i++, p++) {
+ if (isprint(string[i])) {
+ if (!buffer)
+ continue;
+ buffer[p] = string[i];
+ } else {
+ char numstr[5];
+
+ snprintf(numstr, sizeof(numstr), "\\x%02x",
+ (unsigned int)(string[i]) & 0xff);
+
+ if (!buffer) {
+ buffer = zalloc(i + (len - i) * 4 + 2);
+ if (!buffer) {
+ pr_err("failed to set unprintable string '%s'\n", string);
+ return bt_ctf_field_string_set_value(field, "UNPRINTABLE-STRING");
+ }
+ if (i > 0)
+ strncpy(buffer, string, i);
+ }
+ strncat(buffer + p, numstr, 4);
+ p += 3;
+ }
+ }
+
+ if (!buffer)
+ return bt_ctf_field_string_set_value(field, string);
+ err = bt_ctf_field_string_set_value(field, buffer);
+ free(buffer);
+ return err;
+}
+
static int add_tracepoint_field_value(struct ctf_writer *cw,
struct bt_ctf_event_class *event_class,
struct bt_ctf_event *event,
@@ -270,8 +308,7 @@ static int add_tracepoint_field_value(struct ctf_writer *cw,
}
if (flags & FIELD_IS_STRING)
- ret = bt_ctf_field_string_set_value(field,
- data + offset + i * len);
+ ret = string_set_value(field, data + offset + i * len);
else {
unsigned long long value_int;