From: Wang Nan Date: Fri, 27 May 2016 11:35:51 +0000 (+0000) Subject: perf ctf: Convert invalid chars in a string before set value X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5ea5888b2fbf5b230da62b2a21c8247bebb6c9cf;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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 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 Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa 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 --- 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;