在 C++ 中使用 ifstream 打开和关闭后，.txt 文件不再由 snmptrapd 守护进程写入。

Question

我正在运行 Net-Snmp（环境是运行 Linux Mint OS 11 的虚拟机），并将其配置为将陷阱信息发送到我称为 trapd.txt 的文本文件。

如果我重新启动虚拟机，生成的任何陷阱都会毫无问题地发送到该文件。但是，如果我使用 ifstream 运行 C++ 程序来打开它，然后关闭它，则在重新启动之前，无法再次向其中写入陷阱信息。

当我在此状态下生成陷阱时，有时甚至会看到 trapd.txt 文件在 GUI 中闪烁，就好像它尝试写入但失败一样。如果我进行干净的重新启动并单独运行以下代码，就会发生这种情况：

ifstream file;
file.open("trapd.txt");
if(file)
    cout<<"open"<<endl;
file.close();
file.open("nothing.txt");
file.close();
exit(0);

显然，此代码不会更改权限或 SNMP 配置文件。我认为阻止陷阱信息随后进入的唯一原因是 ifstream 实际上并未完全关闭。

如果您有任何修复或解决方法的想法或任何见解，我将非常感激！这对我来说相当重要......

这是我的 snmp.conf 文件：

oidOutputFormat 1
oidOutputFormat 5
logTimestamp yes
escapeQuotes yes

snmptrapd.conf：

authCommunity log,execute,net public
authCommunity log,execute,net private
outputOption auSs
logOption f /home/utd/Desktop/REPO/src/Manager/trapd.txt

snmpd.conf：

authtrapenable 1
master all
linkUpDownNotifications yes
defaultMonitors yes
trap2sink localhost public
rwcommunity private localhost
rocommunity public localhost
###############################################################################
#
# EXAMPLE.conf:
#   An example configuration file for configuring the Net-SNMP agent ('snmpd')
#   See the 'snmpd.conf(5)' man page for details
#
#  Some entries are deliberately commented out, and will need to be explicitly     activated
#
###############################################################################
#
#  AGENT BEHAVIOUR
#

#  Listen for connections from the local system only
agentAddress  udp:127.0.0.1:161
#  Listen for connections on all interfaces (both IPv4 *and* IPv6)
#agentAddress udp:161,udp6:[::1]:161


###############################################################################
#
#  SNMPv3 AUTHENTICATION
#
#  Note that these particular settings don't actually belong here.
#  They should be copied to the file /var/lib/snmp/snmpd.conf
#     and the passwords changed, before being uncommented in that file *only*.
#  Then restart the agent

#  createUser authOnlyUser  MD5 "remember to change this password"
#  createUser authPrivUser  SHA "remember to change this one too"  DES
#  createUser internalUser  MD5 "this is only ever used internally, but still change the password"

#  If you also change the usernames (which might be sensible),
#  then remember to update the other occurances in this example config file to match.


###############################################################################
#
#  ACCESS CONTROL
#
                                             #  system + hrSystem groups only
view   systemonly  included   .1.3.6.1.2.1.1
view   systemonly  included   .1.3.6.1.2.1.25.1

                                             #  Full access from the local host
                                             #  Default access to basic system info

                                             #  Full access from an example network
                                             #     Adjust this network address to match your local
                                             #     settings, change the community string,
                                             #     and check the 'agentAddress' setting above

                                             #  Full read-only access for SNMPv3
  rouser   authOnlyUser
                                             #  Full write access for encrypted requests
                                             #  Remember to activate the 'createUser' lines above
#rwuser   authPrivUser   priv

#  It's no longer typically necessary to use the full 'com2sec/group/access' configuration
#  r[ou]user and r[ow]community, together with suitable views, should cover most requirements


###############################################################################
#
#  SYSTEM INFORMATION
#

#  Note that setting these values here, results in the corresponding MIB objects being 'read-only'
#  See snmpd.conf(5) for more details
sysContact     Me <[email protected]>
                                             # Application + End-to-End layers
sysServices    72


#
#  Process Monitoring
#
                           # At least one  'mountd' process
proc  mountd
                           # No more than 4 'ntalkd' processes - 0 is OK
proc  ntalkd    4
                           # At least one 'sendmail' process, but no more than 10
proc  sendmail 10 1

#  Walk the UCD-SNMP-MIB::prTable to see the resulting output
#  Note that this table will be empty if there are no "proc" entries in the snmpd.conf file


#
#  Disk Monitoring
#
                           # 10 MB required on root disk, 5% free on /var, 10% free on all other disks
disk       /     10000
disk       /var  5%
includeAllDisks  10%

#  Walk the UCD-SNMP-MIB::dskTable to see the resulting output
#  Note that this table will be empty if there are no "disk" entries in the snmpd.conf file


#
#  System Load
#
                           # Unacceptable 1-, 5-, and 15-minute load averages
load   12 10 5

#  Walk the UCD-SNMP-MIB::laTable to see the resulting output
#  Note that this table *will* be populated, even without a "load" entry in the snmpd.conf file


###############################################################################
#
#  ACTIVE MONITORING
#
                                #   Send SNMPv1  traps
                                #   Send SNMPv2c traps
                                #   Send SNMPv2c INFORMs

#  Note that you typically only want *one* of these three lines
#  Uncommenting two (or all three) will result in multiple copies of each notification.


#
#  Event MIB - automatically generate alerts
#
                               # Remember to activate the 'createUser' lines above
iquerySecName   internalUser
rouser          internalUser
                               # Generate traps on UCD error conditions
                               # Generate traps on linkUp/Down


###############################################################################
#
#  EXTENDING THE AGENT
#

#
#  Arbitrary extension commands
#
 extend    test1   /bin/echo  Hello, world!
 extend-sh test2   echo Hello, world! ; echo Hi there ; exit 35

            #perl $debugging = \'1\';
            #perl $verbose = \'1\';
            #perl {$regat = \'.1.3.6.1.4.1.8072.999\'; $extenstion = \'1\'; $mibdata = \'/etc/passwd\'; $delimT=\'\'; $delimV=\':\'; do \'/etc/snmp/snmpagent.pl\';}
#perl print STDERR 'Test'
#perl $debugging = '1';
#perl $verbose = '1';
#perl $regat = '.1.3.6.1.4.8072.999';
#perl $extenstion = '1';
#perl $mibdata = '/etc/passwd';
#perl $delimT='';
#perl $delimV=':';
#perl do '/home/utd/snmpagent.pl';
#perl print STDERR 'Now loading Perl extensions...\n'
#perl $mibdata = "dick.txt";
#perl do '/home/utd/mymod.pl';
#extend-sh test3   /bin/sh /tmp/shtest

#  Note that this last entry requires the script '/tmp/shtest' to be created first,
#    containing the same three shell commands, before the line is uncommented

#  Walk the NET-SNMP-EXTEND-MIB tables (nsExtendConfigTable, nsExtendOutput1Table
#     and nsExtendOutput2Table) to see the resulting output

#  Note that the "extend" directive supercedes the previous "exec" and "sh" directives
#  However, walking the UCD-SNMP-MIB::extTable should still returns the same output,
#     as well as the fuller results in the above tables.


#
#  "Pass-through" MIB extension command
#
#pass .1.3.6.1.4.1.8072.2.255  /bin/sh       PREFIX/local/passtest
#pass .1.3.6.1.4.1.8072.2.255  /usr/bin/perl PREFIX/local/passtest.pl

# Note that this requires one of the two 'passtest' scripts to be installed first,
#    before the appropriate line is uncommented.
# These scripts can be found in the 'local' directory of the source distribution,
#     and are not installed automatically.

#  Walk the NET-SNMP-PASS-MIB::netSnmpPassExamples subtree to see the resulting output


#
#  AgentX Sub-agents
#
                                       #  Run as an AgentX master agent
 master          agentx
                                       #  Listen for network connections (from localhost)
                                       #  rather than the default named socket /var/agentx/master
#agentXSocket    tcp:localhost:705
perl $mibdata = "/etc/snmp/agenty.conf";
perl do "/etc/snmp/agenty.pl";

Answer 1

问题的根源实际上是我自己使用gedit编辑并保存了文件本身。虽然我仍然不明白为什么这会导致问题，但我可以通过不编辑文件来解决它。感谢所有回复的人。