用GDB 调试system_monitor

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Easy debug with GDB, step by step.

Debug process: system_monitor

Debug platform: Riogrande, Lotus

1. Build lotus eng or debug version

1) Remove the followings in device/semc/riogrande/files/init.riogrande.rc

# SEMC System monitor

#service system_monitor /system/bin/system_monitor

# user root

2) For not running system_monitor as service

2. Flash the sins into mobile phone

3. Setup GDB environment

1) sudo apt-get install semc-gdb-arm semc-python-gdb

2) https://wiki.sonyericsson.net/androiki/GDB_debugging

3) https://wiki.sonyericsson.net/mib/GDB_Tool_Course

4. Open two terminal windows, one for gdbclient, another for gdbserver

5. In one terminal window for gdbserver

1) $adb remount

2) $adb push gdbserver73 /system/bin/gdbserver //gdbserver73 is the enclosure.

3) $adb shell

4) #chmod 777 /system/bin/gdbserver

5) #gdbserver :5039 /system/bin/system_monitor

Show the following infomation

Process /system/bin/system_monitor created; pid = 2678

Listening on port 5039

Remote debugging from host 127.0.0.1 //later show the information after gdbclient runs

6. In another terminal window for gdbclient

1) Firstly, enter the root directory of edream6.0-riogrande-xxx source code

For example: xx@xx: /…./edream6.0-riogrande-plus-release$

2) xx@xx: /…./edream6.0-riogrande-plus-release$. build/envsetup.sh

3) xx@xx: /…./edream6.0-riogrande-plus-release$lunch lotus-eng or lunch lotus-userdebug

4) xx@xx: /…./edream6.0-riogrande-plus-release$adb forward tcp:5039 tcp:5039

5) xx@xx: /…./edream6.0-riogrande-plus-release$setpaths

6) xx@xx: /…./edream6.0-riogrande-plus-release$gdbclient system_monitor

Show the following information:

If you haven't done so already, do this first on the device:

gdbserver :5039 /system/bin/system_monitor

gdbserver :5039 --attach

GNU gdb (GDB) 7.1-android-gg2

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law. Type "show copying"

and "show warranty" for details.

This GDB was configured as "--host=x86_64-linux-gnu --target=arm-elf-linux".

For bug reporting instructions, please see:

<http://www.gnu.org/software/gdb/bugs/>...

Reading symbols from /media/Disk1T/CodeResources/Lotus/edream6.0-riogrande-plus-release/out/target/product/lotus/symbols/system/bin/system_monitor...done.

BFD: /media/Disk1T/CodeResources/Lotus/edream6.0-riogrande-plus-release/out/target/product/lotus/symbols/system/bin/linker: warning: sh_link not set for section `.ARM.exidx'

__dl__start () at bionic/linker/arch/arm/begin.S:35

35 mov r0, sp

(gdb)

7) (gdb)info break //show all breakpoints information

No breakpoints or watchpoints.

8) (gdb) b sysmon.c:main //set breakpoint on the main function of sysmon.c

Breakpoint 1 at 0xba54: file vendor/semc/hardware/sysmon/sysmon.c, line 279.

9) (gdb) c //continue to run the process of system_monitor

Continuing.

Breakpoint 1, main (argc=1, argv=0xbef0abc4) at vendor/semc/hardware/sysmon/sysmon.c:279

279 int ret = 0;

10) (gdb) bt //show the call stack

#0 main (argc=1, argv=0xbef0abc4) at vendor/semc/hardware/sysmon/sysmon.c:279

11) (gdb) info args //show Argument variables of current stack frame

argc = 1

argv = 0xbef0abc4

12) (gdb) n //Next line. Overstepping the function

281 if (!td) {

13) (gdb) info locals //show Local variables of current stack frame

ret = 0

__PRETTY_FUNCTION__ = "main"

14) (gdb) l //List specified function or line.

276

277 int main(int argc, char **argv)

278 {

279 int ret = 0;

280

281 if (!td) {

282 LOGE("%s - Local data structure not allocated\n", __func__);

283 return -ENOMEM;

284 }

285

15) (gdb) print td //Print value of expression EXP

$1 = (struct sysmon *) 0xf028

16) (gdb) ptype td //Print definition of type TYPE.

type = struct sysmon {

char *plugin_path;

char *config_file;

char *socket_path;

pthread_mutex_t lock;

int num_socket_clients;

} *

17) (gdb) print td.plugin_path //Print someone value in the td struct

$2 = 0xf040 "/system/lib/sysmon/"

18) (gdb) list parse_options // List specified function or line.

236

237 flags |= PRINT_DONE;

238 }

239

240 static int parse_options(int argc, char **argv, struct sysmon *td)

241 {

242 int opt;

243 const char *opts = "c:p:s:n:hla";

244

245 while ((opt = getopt(argc, argv, opts)) != -1) {

19) (gdb) break 245 // set breakpoint on the line 245

Breakpoint 2 at 0xb904: file vendor/semc/hardware/sysmon/sysmon.c, line 245.

20) (gdb) info break //show all breakpoints information

Num Type Disp Enb Address What

1 breakpoint keep y 0x0000ba54 in main at vendor/semc/hardware/sysmon/sysmon.c:279

breakpoint already hit 1 time

2 breakpoint keep y 0x0000b904 in parse_options at vendor/semc/hardware/sysmon/sysmon.c:245

21) (gdb) delete 1 //delete the breakpoint whose Num is 1

(gdb) info break

Num Type Disp Enb Address What

2 breakpoint keep y 0x0000b904 in parse_options at vendor/semc/hardware/sysmon/sysmon.c:245

22) (gdb) c //Continue execution

Continuing.

Breakpoint 2, parse_options (argc=1, argv=0xbef0abc4, td=0xf028) at vendor/semc/hardware/sysmon/sysmon.c:245

245 while ((opt = getopt(argc, argv, opts)) != -1) {

23) (gdb) print argc // Print value of expression EXP

$4 = 1

(gdb) print argv

$5 = (char **) 0xbef0abc4

(gdb) print argv[0]

$6 = 0xbef0acb3 "/system/bin/system_monitor"

(gdb) print opts

$7 = 0xcea8 "c:p:s:n:hla"

24) (gdb) n //next line. Overstepping the function

//I don’t know why there is error?

Program received signal SIGSEGV, Segmentation fault.

0x00008d30 in ?? ()

25) Restart gdbserver and gdbclient

(gdb) break sysmon.c:parse_options

Breakpoint 1 at 0xb8fe: file vendor/semc/hardware/sysmon/sysmon.c, line 243.

(gdb) c

Continuing.

Breakpoint 1, parse_options (argc=1, argv=0xbe936bc4, td=0xf028) at vendor/semc/hardware/sysmon/sysmon.c:243

243 const char *opts = "c:p:s:n:hla";

(gdb) l

238 }

239

240 static int parse_options(int argc, char **argv, struct sysmon *td)

241 {

242 int opt;

243 const char *opts = "c:p:s:n:hla";

244

245 while ((opt = getopt(argc, argv, opts)) != -1) {

246 switch (opt) {

247 case 'c':

(gdb) l

248 free(td->config_file);

249 td->config_file = strdup(optarg);

250 break;

251 case 'p':

252 free(td->plugin_path);

253 td->plugin_path = strdup(optarg);

254 break;

255 case 's':

256 free(td->socket_path);

257 td->socket_path = strdup(optarg);

(gdb) l

258 break;

259 case 'n':

260 td->num_socket_clients = atoi(optarg);

261 break;

262 case 'l':

263 flags |= PRINT_SENSORS;

264 break;

265 case 'a':

266 flags |= PRINT_ACTIONS;

267 break;

(gdb) l

268 case 'h':

269 default:

270 print_usage();

271 return -EINVAL;

272 }

273 }

274 return 0;

275 }

276

277 int main(int argc, char **argv)

26) (gdb) break 274

Breakpoint 2 at 0xba22: file vendor/semc/hardware/sysmon/sysmon.c, line 274.

27) (gdb) c

Continuing.

Breakpoint 2, parse_options (argc=1, argv=0xbe936bc4, td=0xf028) at vendor/semc/hardware/sysmon/sysmon.c:274

274 return 0;

28) (gdb) info locals // ShowLocal variables of current stack frame

opt = -1

opts = 0xcea8 "c:p:s:n:hla"

29) (gdb) print opt

$1 = -1

30) (gdb) n

275 }

31) (gdb)

main (argc=1, argv=0xbe936bc4) at vendor/semc/hardware/sysmon/sysmon.c:287

287 if (ret) {

32) (gdb) n

//I don’t know why this happens?

Stopped due to shared library event

33) (gdb)

notify_gdb_of_load (info=0xb0009f48) at bionic/linker/linker.c:230

230 insert_soinfo_into_debug_map(info);

34) (gdb) return //Make selected stack frame return to its caller

Make notify_gdb_of_load return now? (y or n) y

35) It is no useful, Restart gdbserver and gdbclient

36) (gdb) break sysmon.c:292

Breakpoint 1 at 0xbab6: file vendor/semc/hardware/sysmon/sysmon.c, line 292.

37) (gdb) c

Continuing.

Breakpoint 1, main (argc=1, argv=0xbeba0bc4) at vendor/semc/hardware/sysmon/sysmon.c:292

292 ret = load_plugins(td);

38) (gdb) n //I don’t know why share lib cannot be mapped