當這個“期望”腳本啟動時，為什麼 gdb 客戶端無法與其 gdb 伺服器通信？

我正在為韌體程式碼庫建構一個持續集成環境，使用 Segger JLink 設備對 ARM Cortex M0 進行程式，並使用 gdb 和 Segger 的 RTT 工具在目標上執行測試。

我需要從“期望”開始三個過程：

1. gdb 伺服器。這會監聽來自…的連接
2. gdb 客戶端。
3. Segger 的 RTT 客戶端將目標的輸出記錄到主機終端，這樣我就可以看到測試是如何進行的。

我為其中的每一個都有“制定”目標。當我以人類身份執行測試時，我會為每個測試打開一個終端選項卡。在終端中一一執行，它們都執行良好。但是，當通過以下“expect”腳本執行時，gdb 客戶端將停止在它應該向 gdb 伺服器發送內容的位置。為什麼？

#!/usr/bin/expect

# Bike Tracker firmware/hardware test. For syntax, see "man expect".

# gdb server
spawn /Applications/SEGGER/JLink/JLinkGDBServer -device nrf51822 -if swd -speed 4000 -port 2331
expect {
 -ex "Waiting for GDB connection..."
}
sleep 1
send_user "\nexpect: gdb server running OK\n"

# gdb client
spawn ~/dev/gcc-arm-none-eabi-4_9-2015q1/bin/arm-none-eabi-gdb -x ./_build/.gdbinit ./_build/biketracker_app_s130.elf
sleep 2
set timeout 10
expect {
 -ex "(gdb)" {
   send "cont"
   send "cont"
 }
 -ex "Operation timed out" {
   send_user "expect: Timed out on gdb client. Did the server start OK?\n"
   exit 1
 }
 timeout {
   send_user "\nexpect: Timed out on gdb client output.\n"
   exit 1
 }
}
send_user "\nexpect: gdb client running OK\n"

# Segger RTT client
spawn /Applications/SEGGER/JLink/JLinkRTTClient -device nrf51822 -if swd -speed 4000
# If we do an RX operation on the modem, that takes 6s for the TX and about 30s for the RX.
set timeout 40
expect {
 -ex "END_OF_TEST" { exit 0 }
 eof { exit 0 }
 -ex "ASSERT" {
   send_user "\nexpect: A test failed. See RTT output for details.\n"
   exit 1
 }
 timeout {
   send_user "\nexpect: Timed out on RTT output.\n"
   exit 1
 }
}

終端輸出：

expect test.expect
spawn /Applications/SEGGER/JLink/JLinkGDBServer -device nrf51822 -if swd -speed 4000 -port 2331
SEGGER J-Link GDB Server V5.12f Command Line Version

JLinkARM.dll V5.12f (DLL compiled May 17 2016 16:04:43)

-----GDB Server start settings-----
GDBInit file:                  none
GDB Server Listening port:     2331
SWO raw output listening port: 2332
Terminal I/O port:             2333
Accept remote connection:      yes
Generate logfile:              off
Verify download:               off
Init regs on start:            off
Silent mode:                   off
Single run mode:               off
Target connection timeout:     0 ms
------J-Link related settings------
J-Link Host interface:         USB
J-Link script:                 none
J-Link settings file:          none
------Target related settings------
Target device:                 nrf51822
Target interface:              SWD
Target interface speed:        4000kHz
Target endian:                 little

Connecting to J-Link...
J-Link is connected.
Firmware: J-Link ARM V8 compiled Nov 28 2014 13:44:46
Hardware: V8.00
S/N: 268006243
OEM: SEGGER-EDU
Feature(s): FlashBP, GDB
Checking target voltage...
Target voltage: 3.04 V
Listening on TCP/IP port 2331
Connecting to target...Connected to target
Waiting for GDB connection...
expect: gdb server running OK
spawn ~/dev/gcc-arm-none-eabi-4_9-2015q1/bin/arm-none-eabi-gdb -x ./_build/.gdbinit ./_build/biketracker_app_s130.elf
GNU gdb (GNU Tools for ARM Embedded Processors) 7.8.0.20150304-cvs
Copyright (C) 2014 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 "--host=x86_64-apple-darwin10 --target=arm-none-eabi".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./_build/biketracker_app_s130.elf...done.
0x0002ecf2 in rx_done_event (bytes=1 '\001', p_data=0x20002cec &lt;rx_buffer&gt; ",") at /Users/Eliot/dev/nRF5_SDK_11.0.0_89a8197/components/drivers_nrf/uart/nrf_drv_uart.c:631
631     m_cb.handler(&event,m_cb.p_context);
Loading section .text, size 0x1fbec lma 0x1b000

expect: Timed out on gdb client output.

問題可能是gdb伺服器輸出被阻塞了，因為沒有人讀取它，所以gdb客戶端也被阻塞了。您可以expect閱讀並忽略 gdb 的其餘輸出

expect_background eof exit

這使得最後生成的命令繼續其輸出，直到讀取文件結尾。

引用自：https://unix.stackexchange.com/questions/304650