写聊天室的过程中出现的问题

最新推荐文章于 2022-03-12 17:34:39 发布

erfenjiao

最新推荐文章于 2022-03-12 17:34:39 发布

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分类专栏：聊天室

本文链接：https://blog.youkuaiyun.com/daisy_g_jasmine/article/details/119057997

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文章目录

问题一套接字(已解决)

有关套接字，服务器端套接字创建的时候用的是fd，创建线程时换成了sock_fd，运行服务器端没有出问题，客户端一运行就直接退出，后来用了gcc -I/usr/local/mysql/include/mysql main_cli.c -L/usr/local/mysql/lib -lmysqlclient -ldl -lpthread -o main_cli -g -fsanitize=address这条命令后面的错误检查功能，发现问题是没有套接字，把fd换掉，可以运行。

问题二不能开多个客户端(已解决)

服务器端开启，再开启客户端，发现只能开一个，套接字conn_fd = 0,再开第二个，创建的还是套接字conn_fd = 0。
猜想：应该是套接字那里出了问题，先单独摘出来找错误。
1.报错内容如下：

连接成功！套接字conn_fd = 0
连接成功！套接字conn_fd = 0
epoll_ctl: File exists
line : 126

line：126行为：

epoll_ctl(kdpfd , EPOLL_CTL_ADD , conn_fd , &ev);

2.接下来，检查epoll的创建过程，看看有无问题

if(events[i].data.fd == sock_fd)      //用于监听的套接字
            {
                if((conn_fd = accept(sock_fd , (struct sockaddr *)&cli , &socklen )) < 0)
/实际上是这一行有问题，conn_fd没有赋值成功/
                {
                    my_err("accept",__LINE__);
                }
                printf("连接成功！套接字conn_fd = %d\n",conn_fd);
                acceptcont++; //连接数++
                                                          
                ev.events = EPOLLIN | EPOLLET;
                ev.data.fd = conn_fd;   
                
                if(epoll_ctl(kdpfd , EPOLL_CTL_ADD , conn_fd , &ev) < 0)
                {
                    my_err("epoll_ctl",__LINE__);
                }
这一行报错//
                curfds++;
                continue;
            }

加上一个括号问题解决。

问题三数据库创建（已解决）

代码参考
将数据库单独放出来检查，出现如下问题

AddressSanitizer:DEADLYSIGNAL
=================================================================
==14116==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000050 (pc 0x7f3d94e948f0 bp 0x7ffc3fee8fe0 sp 0x7ffc3fee89c8 T0)
==14116==The signal is caused by a READ memory access.                                                                                                                                         
==14116==Hint: address points to the zero page.
    #0 0x7f3d94e948ef  (/usr/local/lib/libmysqlclient.so.21+0x3a8ef)
    #1 0x4015ca in main /home/erfenjiao/vs/c/ChatRoom/mysql.c:56
    #2 0x7f3d94c9709a in __libc_start_main ../csu/libc-start.c:308
    #3 0x4011f9 in _start (/home/erfenjiao/vs/c/ChatRoom/mysql+0x4011f9)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/local/lib/libmysqlclient.so.21+0x3a8ef) 
==14116==ABORTING

1.搜索得，可能是内存泄漏的问题。
2.继续检查得出，是因为数据库以及表需要自己创建。
3.创建表，此代码只完成查找功能，需手动填写数据
4.手动填写时，出现问题

MariaDB [happy]>  insert into tbb_user (username , userid) values (’zhangsan’, 1);
ERROR 1054 (42S22): Unknown column '’zhangsan’' in 'field list'
MariaDB [happy]>  insert into tbb_user (username , userid) values (zhangsan, 1);
ERROR 1054 (42S22): Unknown column 'zhangsan' in 'field list'

ERROR 1054 (42S22): Unknown column ‘zhangsan’ in 'field list’问题解决
5.解决问题，是单引号和点的问题
6.成功填入信息
7.运行结果一致，完成

问题五 deal函数中的遗漏（已解决）

在服务器的deal函数那里，还有数据库的函数mysql_accept()，已补充。
此问题是由检查问题二找出来的，本来以为填了数据库函数就能解决问题二，但显然是我太天真

问题六注册卡住不动(已解决)

+------------------+
|  1. login        |
|  2. regisister   |
|  3. admin        |
|  4. exit         |
+------------------+

进入到这个界面，无论选哪一个，都会在随着提示输入完账号和密码后，卡住，无法进行到下一步。

这个问题随着第二个问题的解决有了新的进展，注册时跟着指引完成，服务器端反而退出了.

解决掉文件无法打开以及数据库sql语句错误后，注册这一步成功完成。

问题七注册部分代码无法继续运行(已解决)

printf("注册成功!!\n");
printf("您的账号为:%d\n", send_pack->data.send_account);

这两行没有打印

问题八 epoll_wait(已解决)

nfds = epoll_wait(kdpfd , events , size , -1) ;  
printf("%d\n",nfds);

运行结果

109、、、、、、、、、、、、、
nfds = 1 curfds = 1
连接成功！套接字conn_fd = 6
nfds = 1 curfds = 2
645、、、、、、出错、、、、、、、
line : 648
fopen: No such file or directory
nfds = -1 curfds = 2
line : 122
epoll_wait: Interrupted system call

猜想：是不是因为文件无法打开，数据没有办法写入，然后出错，在下一轮循环中才产生了epoll_wait 报错？
在本目录创建一个文件后，产生了一个新的sql语句问题，如下：

nfds = 1 curfds = 1
连接成功！套接字conn_fd = 6
nfds = 1 curfds = 2
Query failed (You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1)
nfds = -1 curfds = 2
120、、、、、、出错、、、、、、、
line : 121
epoll_wait: Interrupted system call

检查得，数据库sql语句少了一个括号，补充后，注册账号成功，检查数据库的user_data表，发现填充成功。

问题九 $$sad(已解决)

输入账号和密码后，会出现$$sad 这个符号，然后就无法往下进行，错误信息如下：

连接成功！套接字conn_fd = 7
nfds = 1 curfds = 3
$$sad

找到了sad的位置

if (!mysql_fetch_row(result)) 
{
	recv_pack.type = ACCOUNT_ERROR;
    memset(recv_pack.data.write_buff, 0, sizeof(recv_pack.data.write_buff));
    printf("$$sad\n");
    strcpy(recv_pack.data.write_buff, "passwd error");
    if ((send(events[i].data.fd, &recv_pack, sizeof(PACK), 0)) < 0) 
    {
         my_err("send", __LINE__);
    }                     
    pthread_mutex_unlock(&mutex);
    continue;
}

问题⑩ 账号与密码问题(已解决)

number = 100 取消了之后也没啥用哎，他界面上而不是数据库里显示的账号也没有办法登上去。
为什么我的账号他登不上去…T__T
1.灵魂拷问：account到底算账号，还是算昵称？
答：是账号，那我数据库里那个咋存的是昵称?
2.既然account是账号，那么user_number就不是账号了，等等，是不是名称就错了，应该是user_name?
3.那user_number确实是分配账号了呀？
答：user_number确实是在分配数字，但是数据表里面不一定需要的是这个名字，顶着account这个名字。
4.重新建一张表，如下：

+------------+-----------+--------+------------+--------+
| account    | user_name | passwd | user_state | socket |
+------------+-----------+--------+------------+--------+
| 1155523951 | 小王       | 1234    |          0|      6|
+------------+-----------+--------+------------+--------+

问题十一添加好友建表(已解决)

添加好友步骤，在没有添加好友之前，输入账号，却总是报错“已经有此好友或者此好友不存在”。
检查得：总是写不到数据库中，在数据库相关的部分查找，发现是数据库的名字写错了，少了一个‘s’

问题十二%d 和 %s 一定不能搞混了！！（已解决）

在服务器端的add_friend()函数中，出现了一个问题，导致这个函数一直不能运行，终端给出的报错如下：

AddressSanitizer:DEADLYSIGNAL
=================================================================
==16840==ERROR: AddressSanitizer: SEGV on unknown address 0x000044dfe575 (pc 0x7f11cc8c3552 bp 0x7f11c89fd500 sp 0x7f11c89fcc38 T2)                                                                                                                 
==16840==The signal is caused by a READ memory access.                                                                    
    #0 0x7f11cc8c3551  (/lib/x86_64-linux-gnu/libasan.so.5+0x103551)
    #1 0x7f11cc81388c  (/lib/x86_64-linux-gnu/libasan.so.5+0x5388c)
    #2 0x7f11cc81476e in vsprintf (/lib/x86_64-linux-gnu/libasan.so.5+0x5476e)
    #3 0x7f11cc8149f6 in __interceptor_sprintf (/lib/x86_64-linux-gnu/libasan.so.5+0x549f6)
    #4 0x40ca07 in add_fir /home/erfenjiao/vs/c/ChatRoom/my_friends.c:76
    #5 0x403fc6 in deal /home/erfenjiao/vs/c/ChatRoom/service.c:286
    #6 0x7f11cbea1fa2 in start_thread /build/glibc-2.28.11/nptl/pthread_create.c:486
    #7 0x7f11cbdd260e in clone (/lib/x86_64-linux-gnu/libc.so.6+0xf960e)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libasan.so.5+0x103551) 
Thread T2 created by T0 here:
    #0 0x7f11cc810db0 in __interceptor_pthread_create (/lib/x86_64-linux-gnu/libasan.so.5+0x50db0)
    #1 0x40338d in main /home/erfenjiao/vs/c/ChatRoom/service.c:157
    #2 0x7f11cbcfd09a in __libc_start_main ../csu/libc-start.c:308

==16840==ABORTING

很长一堆，大意应该是地址的问题，
1.一开始以为是链表的问题，，因为链表地址最容易出错，但是检查过后发现链表正常，那个创建就是要在链表为空的时候创建，if条件没有问题.
2.以为是数据库函数

result  =   mysql_store_result(&mysql);
 row1    =   mysql_fetch_row(result);

这两行导致的问题，直接注释掉，发现代码还是不能运行。
3.偶然间看到，%s 和 %d 的问题，立马交换位置，再次编译运行，成功。
4.这个错误告诉我，一点点马虎都不行，找不出大问题，那么就是小问题，对于细节一定要好好排查！

问题十三 LOOK_LIST(已解决)

好友列表无法显示出来，终端报错如下

=================================================================
==18955==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6270000037b4 at pc 0x00000040e10f bp 0x7fe58a1fde90 sp 0x7fe58a1fde88
WRITE of size 4 at 0x6270000037b4 thread T2
    #0 0x40e10e in look_list /home/erfenjiao/vs/c/ChatRoom/my_friends.c:242
    #1 0x4044f7 in deal /home/erfenjiao/vs/c/ChatRoom/service.c:344
    #2 0x7fe58d650fa2 in start_thread /build/glibc-2.28.11/nptl/pthread_create.c:486
    #3 0x7fe58d58160e in clone (/lib/x86_64-linux-gnu/libc.so.6+0xf960e)

0x6270000037b4 is located 0 bytes to the right of 14004-byte region [0x627000000100,0x6270000037b4)
allocated by thread T2 here:
    #0 0x7fe58e058330 in __interceptor_malloc (/lib/x86_64-linux-gnu/libasan.so.5+0xe9330)
    #1 0x40dd41 in look_list /home/erfenjiao/vs/c/ChatRoom/my_friends.c:219
    #2 0x4044f7 in deal /home/erfenjiao/vs/c/ChatRoom/service.c:344
    #3 0x7fe58d650fa2 in start_thread /build/glibc-2.28.11/nptl/pthread_create.c:486

Thread T2 created by T0 here:
    #0 0x7fe58dfbfdb0 in __interceptor_pthread_create (/lib/x86_64-linux-gnu/libasan.so.5+0x50db0)
    #1 0x40338d in main /home/erfenjiao/vs/c/ChatRoom/service.c:157
    #2 0x7fe58d4ac09a in __libc_start_main ../csu/libc-start.c:308

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/erfenjiao/vs/c/ChatRoom/my_friends.c:242 in look_list
Shadow bytes around the buggy address:
  0x0c4e7fff86a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c4e7fff86b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c4e7fff86c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c4e7fff86d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c4e7fff86e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c4e7fff86f0: 00 00 00 00 00 00[04]fa fa fa fa fa fa fa fa fa
  0x0c4e7fff8700: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c4e7fff8710: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c4e7fff8720: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c4e7fff8730: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c4e7fff8740: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==18955==ABORTING

使用printf打印atoi(row[1])的值，发现会无限循环

atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
atoi(row[1]) = 1155523957
。。。。。。

无限循环是因为永远只读取了一行，数据库读取需要不断地执行读取语句，但是放到循环内部就无法读取下一个，变成这样，如下，就可以实现不断向下读取的问题

while (row= mysql_fetch_row(result))

问题十四无法发送文件(待解决)

客户端报错如下

AddressSanitizer:DEADLYSIGNAL
=================================================================
==21484==ERROR: AddressSanitizer: SEGV on unknown address 0x0000bebebebe (pc 0x7fd38788570c bp 0x7fd3844feb10 sp 0x7fd3844fe420 T1)                                                                                                                 
==21484==The signal is caused by a WRITE memory access.                                                                   
    #0 0x7fd38788570b in _IO_vfscanf_internal /build/glibc-2.28.11/stdio-common/vfscanf.c:1895
    #1 0x7fd387890c1b in __isoc99_vscanf /build/glibc-2.28.11/stdio-common/isoc99_vscanf.c:30
    #2 0x7fd3883ba00c in __interceptor___isoc99_vscanf (/lib/x86_64-linux-gnu/libasan.so.5+0xb000c)
    #3 0x7fd3883ba10e in __interceptor___isoc99_scanf (/lib/x86_64-linux-gnu/libasan.so.5+0xb010e)
    #4 0x405c8f in sendMsg /home/erfenjiao/vs/c/ChatRoom/client.c:863
    #5 0x7fd3879ebfa2 in start_thread /build/glibc-2.28.11/nptl/pthread_create.c:486
    #6 0x7fd38791c60e in clone (/lib/x86_64-linux-gnu/libc.so.6+0xf960e)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /build/glibc-2.28.11/stdio-common/vfscanf.c:1895 in _IO_vfscanf_internal
Thread T1 created by T0 here:
    #0 0x7fd38835adb0 in __interceptor_pthread_create (/lib/x86_64-linux-gnu/libasan.so.5+0x50db0)
    #1 0x408243 in main /home/erfenjiao/vs/c/ChatRoom/client.c:1416
    #2 0x7fd38784709a in __libc_start_main ../csu/libc-start.c:308

==21484==ABORTING