ps auxw | grep obex-da
root 3119 0.0 0.1 4276 1880 pts/1 S+ 13:07 0:00 grep obex-da
root#raspberrypi:/home/pi# sudo obexpushd -B -n
obexpushd 0.11.2 Copyright (C) 2006-2010 Hendrik Sattler
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions.
Listening on bluetooth/[00:00:00:00:00:00]:9
Creating file "abc0.png"
Creating file "abc0.png"
Error: cannot create file: File exists
If the file already exists,
Obexpushd returns an error.
Basically it is unable to overwrite the existing file.
Any solution?
Try first deleting the file before you send the file, by sending PUT request without body or End-Of-Body header.
Then try sending the file again.
Related
I have implemented a new NAS filer recently, and after mounting
it on a Linux server, the Perl interpreter (version 5.005_03) is unable
to recognize the existence of files on that mount:
[root#server ~]# stat /newmount/testfile
File: `/newmount/testfile'
Size: 0 Blocks: 0 IO Block: 65536 regular empty file
Device: 48h/72d Inode: 9262698097446760736 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 500/ testuser) Gid: ( 500/ testuser)
Access: 2017-02-22 16:44:21.218314000 +0200
Modify: 2017-02-22 16:44:21.218314000 +0200
Change: 2017-02-22 16:44:21.218314000 +0200
[root#server ~]# perl -e 'print "File Exists\n" if -e "/newmount/testfile";'
[root#server ~]#
The interesting thing here, is this:
When I try with a newer version of the
interpreter (like perl, v5.8.8) it works:
[root#server ~]# perl -e 'print "File Exists\n" if -e "/newmount/testfile";'
File Exists
[root#server ~]#
What am I missing on the old Perl?
Thanks in advance!
Thanks for anyone trying to help, I found the root cause of the issue.
For anyone facing a similar issue with legacy systems,
check if the storage exporting the NFS mounts is using 64-bit file descriptors.
In my case, switching to 32-bit file descriptors on the storage solved the issue.
I had a similar issue while using Perl.
The mounted nfs directory had perms of 775 and ownership of 0:788
Account running Perl had primary GID of 402 and was also a member of 788.
Error messages indicated "does not exist or is not a directory"
I changed the primary group of the active account to 788 and it began working.
Only posting in the hopes of preventing someone else from ripping out their last remaining hairs.
Tried to start redis-server but got:
26195:C 27 Aug 17:05:11.684 # Warning: no config file specified, using
the default config. In order to specify a config file use redis-server
/path/to/redis.conf
26195:M 27 Aug 17:05:11.684 * Increased maximum number of open files
to 10032 (it was originally set to 1024).
26195:M 27 Aug 17:05:11.685 # Creating Server TCP listening socket
*:6379: bind: Address already in use
Ran lsof -wni tcp:3000 and killed the local host and tried restarting redis-server again and got the same above error.
Tried: ps -aux | grep redis (output below), then sudo kill -9 6379
nick4896 12238 0.0 0.1 41432 9048 ? Sl Aug26 0:14
redis-server *:6379
nick4896 26304 0.0 0.0 21300 984 pts/21 S+ 17:08 0:00 grep
--color=auto redis
And ran sudo service redis-server restart, and got:
Failed to restart redis-server.service: Unit redis-server.service not
found.
Any ideas?
The problem is that symlink redis-server.service to redis.service was deleted.
Command
sudo systemctl enable redis-server
creates the symlink:
Created symlink /etc/systemd/system/redis.service → /lib/systemd/system/redis-server.service.
Came across this, I would suggest systemctl daemon-reload
Not an answer, but to complete Igor Kavzov's answer, this is the code to enter at the terminal:
sudo ln /lib/systemd/system/redis.service /etc/systemd/system/redis-server.service
fuser can show you ONLY if original file is in use.
fuser DOESN'T SHOW YOU IF SYMLINK IS IN USE which calls original file. That's the issue. You don't know if symlink unused and can be removed.
I have started two processes (24261 opened original file and 24262 opened symlink) :
root#server DEV # ls -l /lib64/libgcc_s-4.4.7-20120601.so.1
-rwxr-xr-x 1 root root 93320 Sep 1 2014 /lib64/libgcc_s-4.4.7-20120601.so.1
root#server DEV # ls -l /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so
lrwxrwxrwx. 1 root root 20 Oct 19 2015 /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so -> /lib64/libgcc_s.so.1
root#server DEV #
root#server DEV # tail -f /lib64/libgcc_s.so.1 &
[1] 24261
root#server DEV #
root#server DEV # cd /usr/lib/gcc/x86_64-redhat-linux/4.4.4
root#server DEV # tail -f libgcc_s.so &
[2] 24262
root#server DEV #
root#server DEV # ps -ef | grep tail
root 24261 3265 0 13:39 pts/1 00:00:00 tail -f /lib64/libgcc_s.so.1
root 24262 3265 0 13:39 pts/1 00:00:00 tail -f libgcc_s.so
root 24492 3265 0 13:40 pts/1 00:00:00 grep tail
root#server DEV #
In both cases fuser tells that symlink and original file is in use (there are two processes for each command):
root#server DEV # fuser /lib64/libgcc_s.so.1
/lib64/libgcc_s.so.1: 24261 24262
root#server DEV # fuser /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so
/usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so: 24261 24262
root#server DEV #
But we know that symlink was not used for the first process. It can be even removed and will not affect first process.
Let's say I want to remove 'gcc' package if the package is not in use.
Original file comes from 'libgcc' package.
root#server DEV # rpm -qf /lib64/libgcc_s.so.1
libgcc-4.4.7-11.el6.x86_64
Symlink comes from 'gcc' package:
root#server DEV # rpm -qf /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so
gcc-4.4.7-11.el6.x86_64
If I will remove 'gcc' package which contains only symlink, I will affect second process! How I can see if symlink is unused?
In my case 'ps -ef' shows that I used command:
root 24262 3265 0 13:39 pts/1 00:00:00 tail -f libgcc_s.so
So ps cannot even tell you that symlink was used.
Any Linux guru?
EDITED:
There is partial solution checking cwd - current working directory:
root#server DEV # ls -l /proc/24262/cwd
lrwxrwxrwx 1 root root 0 Jun 20 13:57 /proc/24262/cwd -> /usr/lib/gcc/x86_64-redhat-linux/4.4.4
root#server DEV #
So from here you see the path "/usr/lib/gcc/x86_64-redhat-linux/4.4.4" and you can get file name from ps.
This doesn't work if you do:
root#server DEV # cd /root
root#server DEV # cat script.sh
/usr/bin/tail -f /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so
root#server DEV #
root#server DEV # nohup ./script.sh &
[2] 26713
root#server DEV #
root#server DEV # ls -l /proc/26713/cwd
lrwxrwxrwx 1 root root 0 Jun 20 14:32 /proc/26713/cwd -> /root
It shows cwd for /root, but symlink is inside the script/program. So then you need to check ps chill process for /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so.
root#server DEV # ps -ef | grep 26713
root 26713 3265 0 14:32 pts/1 00:00:00 /bin/sh ./script.sh
root 26714 26713 0 14:32 pts/1 00:00:00 /usr/bin/tail -f /usr/lib/gcc/x86_64-redhat-linux/4.4.4/libgcc_s.so
root 26780 3265 0 14:38 pts/1 00:00:00 grep 26713
root#server DEV #
This is very confusing when you want to automate package removal (if the package is not in use).
It will be great if someone can see simpler way of this. Also if someone can confirm the accuracy of using cwd and ps child processes for symlink in use detection.
What will happen if script.sh would be binary file? Will I still able to see full symlink path in 'ps' or cwd?
Symlinks are not usual files: they cannot be opened with open() like regular files or directories. Symlink actually is just a constant string, which is automatically interpreted internally during path resolution.
Because of that symlinks are not "used" in the sence of utilities like fuser. When you call fuser for symlink, it actually shows info about file pointed by the link.
If by "in use" you mean "one or more programs is using the link as its path name for the file", then there is no way to tell. It could have been used yesterday, and it might be used tomorrow. Unix is designed so that, unless you are specifically using tools designed for that specific purpose, a symlink looks just like the file it points to. Programs like fuser or lsof will just go right through the links without even telling you it's a link.
If by "in use" you mean "points to a valid file", then there are ways to tell. The simplest being ls -L
$ ls -l foo
/bin/ls: cannot access foo: No such file or directory
$ ls -l g
lrwxrwxrwx 1 hymie users 3 2016-06-20 10:09 g -> foo
$ ls -lL g
/bin/ls: cannot access g: No such file or directory
Unfortunately, Linux kernel is designed to assign original file from the symlink in the start up phase. So when the process is running there is no possibility to check if file called directly or through symlink.
All you can do is to check what was current working directory ls -l /proc/<process_id>/cwd, command line arguments strings /proc/<process_id>/cmdline, what user started the process ps -ef | grep <process_id> then you can check user startup scripts and $PATH, ldd can show you which libraries are called from particular library. If you want to restart the process to see if symlink called then strace is your friend.
The premise of this question (identifying unused packages with fuser / lsof) is fundamentally flawed:
Not every file your system needs to work properly will referenced by an open file descriptor at any random time.
For example, you would have a bad time if you removed /bin/systemctl (since things like /sbin/shutdown are symlinks to it), but lsof shows nothing using it.
It's easy to come up with many more examples, like /bin/grep on my system. It's used all over the place in shell scripts, but I don't happen to have any long-running instances of it.
I was wondering what possibilities are available to detect a connection on a tty. My goal is to create an alert in case someone tries to watch what I am doing through the console
First I though about who, which allows to see wether someone is connected and on what tty, but let's say this user isn't logged in, is there still a way of detecting that a tty is opened? Maybe with /dev/tty? Or is it possible to know how many file descriptors are pointing to the file /dev/console and what processes are using the hardware/io? Or maybe using hardware detection with vcs? I actually have no idea how to use/test those.
let's say this user isn't logged in
Each process belongs to some user. The only way to run some code and not being logged in is to write this code in kernel.
I was wondering what possibilities are available to detect a connection on a tty
Try this:
$ lsof /dev/tty0
lsof is a tool for observe open files.
For example, serial console for my development board is /dev/ttyUSB0. So I opened minicom session and also made cat for my TTY file:
$ minicom -D /dev/ttyUSB0
$ cat /dev/ttyUSB0
and checked this:
$ lsof /dev/ttyUSB0
which gave me:
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
minicom 13299 joe 3u CHR 188,0 0t0 135832 /dev/ttyUSB0
cat 13310 joe 3r CHR 188,0 0t0 135832 /dev/ttyUSB0
From this output you can figure out, who (USER) connected to your TTY, and whic program he used (COMMAND, PID).
After closing minicom session and cat, lsof doesn't print anything.
Also it can be done using w command:
$ w | grep ttyUSB0
Output:
joe pts/2 :0 17:57 2:47 0.12s 0.00s minicom -D /dev/ttyUSB0
joe pts/3 :0 17:58 2:39 0.08s 0.00s cat /dev/ttyUSB0
UPDATE
If you don't want to be watched in the way described above (i.e. via open descriptor), you can do next.
Let's say you are using /dev/ttyUSB0. To connect to your console via this file, you must open it first (no matter which way, e.g. using cat or minicom etc.). Once you have opened it, your session can be seen by other users (e.g. by root) just looking if there are open file descriptors for that file (lsof /dev/ttyUSB0).
Now, TTY devices are just character devices, and you can create your own files (nodes) for those devices. Let's see closely to /dev/ttyUSB0 file:
$ ls -l /dev/ttyUSB0
Output:
crw-rw---- 1 root dialout 188, 0 Mar 4 16:07 /dev/ttyUSB0
Here c indicates that this is character device, and we can see that it has major number 188 and minor number 0. Let's create our own node (file) for this device.
$ cd /tmp
$ sudo mknod some_tricky_name c 188 0
$ sudo chown root:dialout some_tricky_name
$ sudo chmod 644 some_trickyname
Now you can connect to this file instead of /dev/ttyUSB0 and nobody's gonna see you:
$ minicom -D /tmp/some_tricky_name
Still, if you are gonna run some shell in this TTY, good administrator still can catch you, looking to /var/log/auth.log. But I believe this technique prevents you from being caught using w or lsof commands.
I would like to create a httpd.conf file to upload to my Apache server. I need to create this file in order to configure the SSLCertificateChainFile. Does anybody have any idea on how to do this?
I dont think you want to create it. You just need to find and configure it. You may try this:
It's possible to configure this there is no "default location" so I usually do:
$ ps -ef | grep apache
which gives me a list like
deploy#cmd01:/$ ps -ef | grep apache
root 4053 1 0 06:26 ? 00:00:04 /usr/sbin/apache2 -k start
www 5189 4053 0 11:00 ? 00:00:00 /usr/sbin/apache2 -k start
www 5199 4053 0 11:00 ? 00:00:00 /usr/sbin/apache2 -k start
...
Then simply run
$ /usr/sbin/apache2 -V
and you will get the details you need, specifically this
Server compiled with....
-D SERVER_CONFIG_FILE="/etc/apache2/apache2.conf"
The httpd.conf file is typically present, you should just be able to add your specific config settings in there.
Where is my httpd.conf file located apache