centos 6.4 amd64

Hi,

I agree there is a potential problem, but I'm not sure about your solution.

You put CentOS 6.4 in the environment field. What does your /bin/sh point at?

In my (more or less default) installation of CentOS 6.4 it points at bash, of version 4.1.2, which seems to be equally happy about either "=" or "==".

At the same time, on Ubuntu 12.04 /bin/sh points at dash; and it accepts "=", although it doesn't work correctly (hence the problem), but with "==" it complains about a syntax error.

So,

• please clarify which shell you are using as /bin/sh, and of which version;
• please create the script:

./1.sh
#!/bin/sh

[ "$EUID" = "0" ] && echo "My EUID with =: $EUID"
[ "$EUID" == "0" ] && echo "My EUID with ==: $EUID"

make it executable and execute twice, first time as a normal non-root user, and then under sudo, and paste the output.

Thanks.

It turns out that the '=' comparison in dash also works correctly, the problem is that EUID is not defined in dash, hence the comparison with 0 is always false. This problem has been fixed in the current tree by defining a local euid as
euid=$(id -u)
and using it further in the comparison. It works both in dash and bash.

But the comparison is still '=', so the question above about your shell version (which understands '==' but not '=') becomes even more important.

Here are some test outputs:

[root@linux_dev_193 ~]# ls -lh /bin/sh

lrwxrwxrwx. 1 root root 4 6月  20 11:46 /bin/sh -> bash

[root@linux_dev_193 ~]# rpm -qa | grep bash

bash-4.1.2-14.el6.x86_64

[root@linux_dev_193 ~]# cat > 1.sh << EOF

> #!/bin/sh

> 

> [ "$EUID" = "0" ] && echo "My EUID with =: $EUID"

> [ "$EUID" == "0" ] && echo "My EUID with ==: $EUID"

> EOF

[root@linux_dev_193 ~]# chmod +x 1.sh

[root@linux_dev_193 ~]# ./1.sh 

My EUID with =: 0

My EUID with ==: 0

And this is my fault, I think it's a supervisor bug, or weird behavior of 'mktemp', see following code:

  wr_logfile=$(mktemp)

  [ "$EUID" = "0" ] && chown $user $wr_logfile

  chmod 600 $wr_logfile

  log_notice "WSREP: Running position recovery with --log_error=$wr_logfile"

  $mysqld_cmd --log_error=$wr_logfile --wsrep-recover

  rp=$(grep "WSREP: Recovered position:" $wr_logfile)

if wr_logfile is empty, and the 'grep' command will hang everything, but in normal shell, mktemp can NOT failed, so it's weird
so, for safety:

  wr_logfile=`mktemp`

  [ -f $wr_logfile ] || return 0

  [ "$EUID" == "0" ] && chown $user $wr_logfile

  chmod 600 $wr_logfile

  log_notice "WSREP: Running position recovery with --log_error=$wr_logfile"

  $mysqld_cmd --log_error=$wr_logfile --wsrep-recover

  rp=$(grep "WSREP: Recovered position:" $wr_logfile)

Hi Seppo,

See the suggestion above about making wsrep-related logic in mysqld_safe.sh slightly safer.

http://bazaar.launchpad.net/~maria-captains/maria/maria-5.5-galera/revision/3511

Nice!