How to find out the function calling process of complex code running as soon as possible

 

summary

Recently in use freeswitch Test send DTMF Code time , There is a problem with the function call process .

fs There are many modules in itself , There are many and complex callback functions registered , Sometimes I see a log , But I don't know where the originator of the process is .

There are usually several ways to sort out the code call process .

1,     Sort out the source code process , The effect is poor when the code is too complex .
2,     Print the log in the calling function , The effect is poor when the code is too complex .
3,     adopt backtrace Function tracks the current stack , Many changes , Lots of details .
4,    gdb debugging , Commands are complex and difficult to remember .

Today, I suddenly thought of a lazy way , It is faster and simpler than the above methods .

Environmental Science

centos7

freeswitch 1.6.19

gcc version 4.8.5

origin

fs The log of is as follows , Simple view , stay dialplan Called in sleep after ,rtp Process start sending DTMF.

EXECUTE sofia/external/[email protected]:5080 sleep(5000)

2022-06-17 14:42:54.890047 [DEBUG] switch_rtp.c:5237 Send start packet for [1] ts=160 dur=160/160/2000 seq=8238 lw=160

however rtp The calling procedures of are too far apart , I haven't seen the source code for a long time, so , Mainly food .

Modify the source code

First find “switch_rtp.c:5237” The location of , Modify the source code , Add a line of assertion judgment .

switch_assert(FALSE);

Back to the fs Compilation and installation .

test

start-up fs, And execute the test command , The log is as follows .

[email protected]> originate {originator_codec=PCMA,origination_caller_id_number=0755110}sofia/external/sip:[email protected]:5080 1001 XML ext_test

…

EXECUTE sofia/external/[email protected]:5080 sleep(5000)

freeswitch: src/switch_rtp.c:5236: do_2833: Assertion `0' failed.

Aborted

Ha , As expected ,fs Program coredump 了

core Stack

stay bin In the directory core file

-rw-------. 1 root root 71778304 Jun 17 15:24 core.14650

Use gdb open core file , And display the stack .

sudo gdb freeswitch core.14650

…

(gdb) bt

#0  0x00007f0b9e371387 in raise () from /lib64/libc.so.6

#1  0x00007f0b9e372a78 in abort () from /lib64/libc.so.6

#2  0x00007f0b9e36a1a6 in __assert_fail_base () from /lib64/libc.so.6

#3  0x00007f0b9e36a252 in __assert_fail () from /lib64/libc.so.6

#4  0x00007f0ba0e8be2a in do_2833 ([email protected]=0x7f0b1c012d98) at src/switch_rtp.c:5236

#5  0x00007f0ba0e8d4fb in rtp_common_read ([email protected]=0x7f0b1c012d98, [email protected]=0x7f0b34040aa4 "", [email protected]=0x7f0b34040ac8, [email protected]=0x7f0b34040ab8, [email protected]=0) at src/switch_rtp.c:7321

#6  0x00007f0ba0e8e59f in switch_rtp_zerocopy_read_frame (rtp_session=0x7f0b1c012d98, [email protected]=0x7f0b34040a60, [email protected]=0) at src/switch_rtp.c:7617

#7  0x00007f0ba0e41990 in switch_core_media_read_frame ([email protected]=0x7f0b3402f3b8, [email protected]=0x7f0b482795d8, [email protected]=0, [email protected]=0, t[email protected]=SWITCH_MEDIA_TYPE_AUDIO) at src/switch_core_media.c:2219

#8  0x00007f0b984f1298 in sofia_read_frame (session=0x7f0b3402f3b8, frame=0x7f0b482795d8, flags=0, stream_id=0) at mod_sofia.c:1044

#9  0x00007f0ba0e2a5d6 in switch_core_session_read_frame ([email protected]=0x7f0b3402f3b8, [email protected]=0x7f0b482795d8, [email protected]=0, [email protected]=0) at src/switch_core_io.c:188

#10 0x00007f0ba0ec426d in switch_ivr_sleep ([email protected]=0x7f0b3402f3b8, [email protected]=5000, [email protected]=SWITCH_TRUE, [email protected]=0x7f0b48279850) at src/switch_ivr.c:294

#11 0x00007f0b7273d5c4 in sleep_function (session=0x7f0b3402f3b8, data=<optimized out>) at mod_dptools.c:2288

#12 0x00007f0ba0e2472b in switch_core_session_exec ([email protected]=0x7f0b3402f3b8, [email protected]=0x1ccfcd8, [email protected]=0x7f0b34053240 "5000") at src/switch_core_session.c:2802

#13 0x00007f0ba0e24cb9 in switch_core_session_execute_application_get_flags ([email protected]=0x7f0b3402f3b8, app=0x7f0b34053238 "sleep", arg=0x7f0b34053240 "5000", [email protected]=0x0) at src/switch_core_session.c:2672

#14 0x00007f0ba0e28ae4 in switch_core_standard_on_execute (session=0x7f0b3402f3b8) at src/switch_core_state_machine.c:353

#15 switch_core_session_run (session=0x7f0b3402f3b8) at src/switch_core_state_machine.c:650

#16 0x00007f0ba0e21f7e in switch_core_session_thread (thread=<optimized out>, obj=0x7f0b3402f3b8) at src/switch_core_session.c:1648

#17 0x00007f0ba0e1dc73 in switch_core_session_thread_pool_worker (thread=0x7f0b3404f340, obj=<optimized out>) at src/switch_core_session.c:1711

#18 0x00007f0ba10d8b10 in dummy_worker (opaque=0x7f0b3404f340) at threadproc/unix/thread.c:151

#19 0x00007f0b9ede5ea5 in start_thread () from /lib64/libpthread.so.0

#20 0x00007f0b9e439b0d in clone () from /lib64/libc.so.6

(gdb)

Click on the tongue , Clear function call process , Take in everything in a glance .

summary

fs There are many modules , Most of the code call chains are long , When it comes to media, the process is more complex and difficult to track .

The sword moves sideways , develop a new method of one 's own .

Empty as usual

Be serious