Hi All,

Hi all, a problem with Fedora core three that seems to recurr after installation.

My executables will not execute. I have all the permissions for execution and they used to execute in RH9.

The only way I can get them to execute is to type:

\bin\tcsh 'executablefilename'

but this is a pain in the arse!

Fedora Core3, Kernel 2.6.9-1.667.

in a console tpye in "./nameoffile" to execute that file.

I dont think that typing ./blah is a great solution. The whole idea is that executables should be executable from anywhere. I have had similar problems using FC2, with files that are in my path, even after running updatedb as root. In my case the files suddenly become executable after a couple of hours. Has anybody else seen this?

Well, it's not!
Executables(or whatever you call them) should only be used by a system administrator.
If you don't like this, you should simply use your root account as default(not recommended for sane people)

PS: Not doing this is one of the many reasons why Windows doesn't work...

jens is right...you shouldn't run installation software as user..only root...and it's a binary file, not executable...executables are for windows only...well unless you use wine, then you can use executables.

GUYS YOU'RE NOT HELPING

OK. Let me define what I meant about executables.... I meant scripts... my SCRIPTS wont execute.

Yes I tried ./filename

I have '.' in the path anyway... There's something more sinister going on.

Thanks All

Could it be that your scripts are not executable?

Uh....
Let me make that more precise.
If you type
what is the output you get? The line should begin with something like
The x-es in there are essential to your script being executable

Do you start your scripts with #!/bin/sh or something?

You say your scripts don't execute. Do you get any error messages? What happens if you try to execute them?

Groetjes,

Kees-Jan

OK, firstly you must set the execute permission on the script if that is not already done.

The permissions, I don't know what you do and dont know, so you may know most of this, but it is easier just to present it as if you dont

with ls -la

-rwxr-xr-x 1 segfault segfault 721 Aug 5 09:19 myScript.sh

Generally speaking, the rwx's at the start (ignoring the first -) refer to three groups of permissions, owner (user), group, others. In the example above, the user (first three chars) show rwx, meaning that the user (owner) has read write and execute permissions. Next is group permissions r-x meaning that people in the same group have read and execute permissions (ie no write permissions) . Lastly is the permissions for others, r-x which in this example is the same permissions as the group users.

If you are interested in setting these permissions using octal notation, search the web for a good explanation. For simplicity you can set rudimentary permissions like read, write and execute using + and - commands to chmod.

+ = add permission
- = remove permission

a = all
u = user (or owner)
g = group
o = other

x = execute
w = write
r = read

eg:

chmod g-r myScript.sh

would remove read permissions from the group (being people in the same group)

giving:

-rwx--xr-x 1 segfault segfault 721 Aug 5 09:19 myScript.sh

So to make your script executable by you (the owner/user) you would use:

chmod u+r myScript.sh

This is a very simplistic explanation of the use of chmod, but google will find you a proper one.

There is a VERY good reason to require the ./ to execute a file in the current directory, and it goes a little sommin like this:

Imagine I do this..

Create a file called ls and place it in the /tmp directory of some machine (the /tmp location is not important, but is used in this example since most users have write access to /tmp)
containing scripting or binary code to do the following pseudo code:

if user executing has root permissions
then do something malicious and invoke the real ls
else
invoke real ls

Then if someone with root privleges types ls in /tmp ............

That is why it is considered a bad idea.

Simply adding . in your path will alliviate the need to place the ./ in front of the executable name, but will leave you open to attack like the one described above.

..segfault

One other thing that I bumped into was that partitions can be set so they don't allow any code to be run. Again, it's a another security measure so malicious code and code from other os's get run. To see if a partition is marked 'exec' or 'noexec', check the /etc/fstab file. Each line represents one partition, and options are on the right. If it's necessary, add the exec option (as root).

Hey all,

sorry for my lack of explanation. By executable, I meant shell scripts, programs, etc, written by the user, not istallalion programs or the like. Surely you should be able to put all of these files (with execute permissions set) into some directory, put that directory in your path, to have access to them from anywhere the user has execute permission. In my case (and from what I can tell aranfitz's) the problem is not that the partition has noexec set, because the files somehow become executable later, and other binaries and executable shell scripts can be run anyway. I use tcsh shell, could this be an issue with this particular shell? Aranfitz, what shell are you using?

Thanks and apologies

Well...
My shell is /bin/tcsh

As I wrote earlier, the only way i can execute is by typing /bin/tcsh before the executable.

As for the other comments, they would have been useful, but I've already tried them. This really is something sinister. However, keep the obvious ones coming, you never know what silly little thing you've missed. It's becoming clear however that this is not particularly common. Has anyone else installed FC3 yet?

aranfitz, to determine your problem you are going to need to give us a lot more information. Tell us exactly what you are tyring to do, what you have attempted, what does work, what doesn't. Give a single complete consise and understandable example from start to finish..

OK,

I gave the kernel version earlier.

The script "compile" looks like:

latex CTAC
bibtex CTAC
latexCTAC
latex CTAC
dvips -t a4 -o CTAC.ps CTAC.dvi

The permissions are set to _rwxrwxrwx

commands that don't work:
$compile
$./compile

commands that do work:
$/bin/tcsh compile
(That's right, I have to tell it which shell to execute it with)

Result of:
$echo $shell
/bin/tcsh

This problem may be coupled to a broader pernissions problem as often I am disallowed access to /dev/hdc (the cdrom device)

Hope this helps

these commands that don't work, what errors do they give?

Is the first line of your script
??

Groetjes,

Kees-Jan

I have put #!/bin/tcsh at the start of the file, but it didn't help.

Thanks