gdb: 打印 sockaddr 指针值

Question

目前我正在尝试部署一个用C++编写的网络应用程序，由于网络问题，它看起来陷入了死循环：

[isaev@feck-5 ~]$ sudo strace -p 26252 -f -e trace=network -s 10000 
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)
[pid 26272] getpeername(30, 0x7f1699ddfb60, [28]) = -1 ENOTCONN (Transport endpoint is not connected)

我需要知道应用程序缺少哪个网络连接。

假设我可以使用 gdb 附加到进程，我如何打印 0x7f1699ddfb60 指向的 truct sockaddr * (man getpeername) 变量的值？

Answer 1

您可以 "downcast" 并通过执行

取消引用指针（或其值）

(gdb) p *((struct sockaddr_in_or_whichever_you_use *) pointer_to_struct_sockaddr)

或

(gdb) p *((struct sockaddr_in_or_whichever_you_use *) 0x7f1699ddfb60)

gdb: 打印 sockaddr 指针值

gdb: print sockaddr pointer value

c++

c

gdb

strace