我们有一台机器使用 tail -f file,查看日志时,使用 ctrl+c 无法中断退出。导致每次使用 ctrl+z 挂起再杀掉,十分麻烦。
正常情况下使用 ctrl+c 会终止前台运行的程序,因为 ctrl+c 会向进程发送一个终止信号。联想到 trap 是不是设置有问题。
问题主机:
[root@zabbix_a5 ~]# lsb_release -a
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.2.1511 (Core)
Release: 7.2.1511
Codename: Core
[root@zabbix_a5 ~]# trap
trap -- '' SIGINT
trap -- '' SIGQUIT
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
正常主机:
[root@VM_85_116_centos test]# lsb_release -a
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.6.1810 (Core)
Release: 7.6.1810
Codename: Core
[root@VM_85_116_centos test]# trap
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
问题主机有下面的设置,导致 SIGINT ( ctrl+c )、SIGQUIT 信号会被忽略。
trap -- '' SIGINT
trap -- '' SIGQUIT
[root@zabbix_a5 ~]# trap
trap -- '' SIGINT
trap -- '' SIGQUIT
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
[root@zabbix_a5 ~]# trap - SIGINT
[root@zabbix_a5 ~]# trap
trap -- '' SIGINT
trap -- '' SIGQUIT
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
[root@VM_85_116_centos ~]# trap -- '' SIGINT
[root@VM_85_116_centos ~]# trap
trap -- '' SIGINT
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
[root@VM_85_116_centos ~]# trap - SIGINT
[root@VM_85_116_centos ~]# trap
trap -- '' SIGTSTP
trap -- '' SIGTTIN
trap -- '' SIGTTOU
问题主机 trap - SIGINT
无法清楚 trap 设置
编写脚本 test.sh
echo '111'
trap 'ls' SIGINT
echo '222'
trap 'ls' SIGINT
echo '333'
trap - SIGINT
分别在正常与问题主机上执行
strace -o output.log -v sh test.sh
问题主机摘要:
write(1, "111\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
write(1, "222\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
write(1, "333\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigaction(SIGINT, {0x456a90, [], SA_RESTORER, 0x7f76eedc7250}, {SIG_IGN, [], SA_RESTORER, 0x7f76eedc7250}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
read(255, "", 81) = 0
exit_group(0) = ?
+++ exited with 0 +++
正常主机摘要:
write(1, "111\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
rt_sigaction(SIGINT, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, {SIG_DFL, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
write(1, "222\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
rt_sigaction(SIGINT, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
write(1, "333\n", 4) = 4
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7fed821c4280}, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigaction(SIGINT, {0x456be0, [], SA_RESTORER, 0x7fed821c4280}, {SIG_DFL, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
read(255, "", 81) = 0
exit_group(0) = ?
+++ exited with 0 +++
执行trap 'ls' SIGINT
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
rt_sigaction(SIGINT, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
执行trap - SIGINT
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigaction(SIGINT, {0x456a90, [], SA_RESTORER, 0x7f76eedc7250}, {SIG_IGN, [], SA_RESTORER, 0x7f76eedc7250}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7fed821c4280}, {0x454380, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigaction(SIGINT, {0x456be0, [], SA_RESTORER, 0x7fed821c4280}, {SIG_DFL, [], SA_RESTORER, 0x7fed821c4280}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
貌似是问题主机少了一次 rt_sigaction 系统调用
将下面的重置命令追加到系统的 /etc/profile 后面,然后再次进入终端,重置成功了。 在终端直接重置为什么不成功,还不清楚。
trap SIGINT
trap SIGQUIT
1
ps1aniuge 2019-07-20 00:24:14 +08:00
楼主你好,我认为你很牛 x,谢谢分享帖子。
yum update kernel。若不行,重装 centos7.6。 |
2
stern123 2019-07-20 09:14:30 +08:00 via iPhone
1,这个问题是突然出现的还是一直就有?
2,在终端下和 X 下都有问题吗?还是仅 ssh 过去出问题? |
3
stern123 2019-07-20 09:18:38 +08:00 via iPhone
我之前遇到的一个问题是:一个热键在终端下能用,但在 Gnome 下却不响应。dmesg 看能发现 gnome 还是会改系统设置的。
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4
notolddriver OP @ps1aniuge 这个是公司的一台比较重要的机器 不可以重装哦。不过现在问题暂时解决了。
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5
notolddriver OP |
6
aliipay 2019-07-25 03:17:08 +08:00
lz 要不 gdb bash 试下? trap 对应函数是 trap_builtin
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