獲取進程編號
ps aux | grep -v grep | grep myapp_as_brpc
www-data 18900 10.1 1.2 9162996 407160 ? Sl 14:42 1:29 ./bin/myapp_as_brpc --flagfile=./conf/dish_as.conf >/dev/null 2>&1 &
啓動gdb進行調試
sudo gdb attach 18900
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-110.el7
Copyright (C) 2013 Free Software Foundation, Inc.
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 "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
attach: No such file or directory.
Attaching to process 18900
Reading symbols from /data/myapp_as_brpc/bin/myapp_as_brpc...done.
Reading symbols from /lib64/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/librt.so.1
...
Reading symbols from /lib64/libgcc_s.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/libgcc_s.so.1
Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done.
[New LWP 19019]
[New LWP 19018]
[New LWP 19017]
...
[New LWP 19007]
[New LWP 18903]
[New LWP 18902]
[New LWP 18901]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libidn.so.11...Reading symbols from /lib64/libidn.so.11...(no debugging symbols found)...done.
(no debugging symbols found)...done.
Loaded symbols for /lib64/libidn.so.11
...
0x00007fe999f2480d in nanosleep () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install cyrus-sasl-lib-2.1.26-23.el7.x86_64 glibc-2.17-292.el7.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-18.el7.x86_64 libcom_err-1.42.9-11.el7.x86_64 libcurl-7.43.0-3.0.cf.rhel7.x86_64 libgcc-4.8.5-28.el7.x86_64 libidn-1.28-4.el7.x86_64 libselinux-2.5-12.el7.x86_64 libssh2-1.4.3-10.el7_2.1.x86_64 libstdc++-4.8.5-28.el7.x86_64 nspr-4.17.0-1.el7.x86_64 nss-3.34.0-4.el7.x86_64 nss-softokn-freebl-3.34.0-2.el7.x86_64 nss-util-3.34.0-2.el7.x86_64 openldap-2.4.44-13.el7.x86_64 openssl-libs-1.0.2k-12.el7.x86_64 pcre-8.32-17.el7.x86_64 zlib-1.2.7-17.el7.x86_64
(gdb)
注：會發現這個時候程序已經卡住了，等待你輸入指令
設置斷點
(gdb) b dish_as_service_impl.cpp:38
Breakpoint 1 at 0xa532ec: file /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp, line 38.
(gdb) b spatial_bs_client.cpp:166
Breakpoint 2 at 0xa509e6: spatial_bs_client.cpp:166. (2 locations)
程序放行(等待進入到設置斷點的地方會自動停下來)
(gdb) c
Continuing.
[New Thread 0x7fe8c77fe700 (LWP 27871)]
[Switching to Thread 0x7fe92d7fa700 (LWP 19002)]
Breakpoint 1, wmsearch::DishAsServiceImpl::dish_search (this=<optimized out>, controller=<optimized out>, request=0x7fe90c9897c0, response=0x7fe90c01d630, done=0x7fe90c0269f0)
at /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp:38
38 /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp: No such file or directory.
(gdb)
注：這個是生產環境，輸入指令 c 之後，馬上就卡住了，從提示來看已經到達設置的第一個斷點了
單步調試&查看變量值
(gdb) n
46 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
47 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
46 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
29 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
46 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
29 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
46 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) n
[New Thread 0x7fe8bf7fe700 (LWP 30245)]
[Thread 0x7fe8c77fe700 (LWP 27871) exited]
[New Thread 0x7fe8c77fe700 (LWP 30293)]
[Thread 0x7fe8bf7fe700 (LWP 30245) exited]
[Thread 0x7fe8c77fe700 (LWP 30293) exited]
47 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/service/dish_as_service_impl.cpp
(gdb) print cntl->remote_side()
value has been optimized out
(gdb) print dishAsLog.log_id
$1 = 56
(gdb)
注：上面print了2次，一次成功打印出了值，一次沒有，提示“value has been optimized out” ，這個是編譯優化造成的，沒法看了，除非重新編譯一下源碼，並禁用編譯優化，參見 https://blog.csdn.net/baidu_38172402/article/details/81152192
繼續運行程序直接運行到下一個斷點
注：這裏，如果沒有斷點就一直運行。
(gdb) c
Continuing.
Breakpoint 2, wmsearch::SpatialBsClient::spatial_bs_search (this=0x225e260, req=std::shared_ptr (count 2, weak 0) 0x7fe8d8220600, resp=std::shared_ptr (count 1, weak 0) 0x7fe8d8a20660,
service_name="spatial-bs", log=log@entry=0x7fe8c49d78a0) at /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp:166
166 /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp: No such file or directory.
(gdb) n
Breakpoint 2, wmsearch::SpatialBsClient::spatial_bs_search (this=0x225e260, req=std::shared_ptr (count 2, weak 0) 0x7fe8d8220600, resp=std::shared_ptr (count 1, weak 0) 0x7fe8d8a20660,
service_name="spatial-bs", log=log@entry=0x7fe8c49d78a0) at /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp:166
166 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp
(gdb) n
[New Thread 0x7fe8bf7fe700 (LWP 949)]
[Thread 0x7fe8bf7fe700 (LWP 949) exited]
171 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp
(gdb) n
[New Thread 0x7fe8bf7fe700 (LWP 962)]
[Thread 0x7fe8bf7fe700 (LWP 962) exited]
172 in /tmp/cpp/xxxxxx/c_search/dish-as-brpc/src/clients/spatial_bs_client.cpp
(gdb) print shop_as_req->x
Attempt to take address of value not located in memory.
(gdb) print request.mutable_external_header()
[New Thread 0x7fe8c77fe700 (LWP 2426)]
[New Thread 0x7fe8bf7fe700 (LWP 2425)]
$2 = (eureka::proto::ExternalHeader *) 0x7fe8d8022a20
(gdb) print request.mutable_external_header().x_eleme_rc_request
[Thread 0x7fe8c77fe700 (LWP 2426) exited]
[Thread 0x7fe8bf7fe700 (LWP 2425) exited]
[New Thread 0x7fe8be9f7700 (LWP 2479)]
$3 = {const std::string &(const eureka::proto::ExternalHeader * const)} 0xcb7bb4 <eureka::proto::ExternalHeader::x_eleme_rc_request() const>
(gdb)
[New Thread 0x7fe8bf7fe700 (LWP 2614)]
[Thread 0x7fe8be9f7700 (LWP 2479) exited]
$4 = {const std::string &(const eureka::proto::ExternalHeader * const)} 0xcb7bb4 <eureka::proto::ExternalHeader::x_eleme_rc_request() const>
(gdb) print request.range_num
$5 = {google::protobuf::uint32 (const eureka::proto::SpatialBsRequest * const)} 0xcb85a2 <eureka::proto::SpatialBsRequest::range_num() const>
清除斷點&終止一個正在調試的程序
(gdb) delete
Delete all breakpoints? (y or n) y
(gdb) kill
Kill the program being debugged? (y or n) y
(gdb) quit
注：僅僅執行delete，程序還是會卡住的
查看所有斷點
i b
查看string類型的值
p (char*)str1