OpenEuphoria

Re: Fatal error when attempting to execute bear.ex from the EuGtk package

• Posted by srb623 Sep 08, 2019
• 873 views

I had a go at writing a Euphoria function to search path variables for a specified filename with the idea being that it could be used to locate ifconfig more generically rather than hard coding /sbin or whatever in your code. Have given it some testing and it looks OK to me but I will let you be the final judge of that. The code is as follows:

-- 
-- Next we need to declare the include files that we require. 
-- 
include std/filesys.e 
include std/sequence.e 
 
-- 
-- Function to return the fully qualified name of the file if the filename FILENAME can 
-- be found in any of the paths listed in the variable PATH or the additional paths to 
-- search EXTRA_PATHS.  The paths in EXTRA_PATHS will be searched before those 
-- in PATH.  If the filename FILENAME cannot be found then an empty string will be 
-- returned. 
-- 
function find_in_path(sequence filename, sequence path, sequence extra_paths = "") 
    sequence path_filename 
    sequence path_list 
     
    sequence path_list1 
    sequence path_list2 
     
    -- 
    -- FIrst we must ensure that the filename FILENAME contains some data and if not we 
    -- return the empty string to the caller. 
    -- 
    if length(filename) = 0 then 
        return "" 
    end if 
     
    -- 
    -- Next we must check to see if the filename FILENAME is a fully qualified name 
    -- and if so we must exit with the current name as it will not be located in any 
    -- of the paths. 
    -- 
    if filename[1] = filesys:SLASH then 
        return filename 
    end if 
     
    -- 
    -- Next we must split the path variable PATH on the path separator and create 
    -- a sequence of strings of the results. 
    -- 
    path_list1 = stdseq:split_any(path, filesys:PATHSEP, , 1) 
     
    -- 
    -- Next we must split the additional paths EXTRA_PATHS on the path separator 
    -- and create a sequence of strings of the results. 
    -- 
    path_list2 = stdseq:split_any(extra_paths, filesys:PATHSEP, , 1) 
     
    -- 
    -- Next we must create the combined list of the two path variables.  As we 
    -- wish to search the extra paths first it must come first in the below. 
    -- 
    path_list  = path_list2 & path_list1 
 
    -- 
    -- Now we need to loop for all paths in the above list and for each of them 
    -- we create a filename and then check for its existence.  If it does then we 
    -- return 'true' to the caller. 
    -- 
    for ix = 1 to length(path_list) do 
        -- 
        -- Now we need to form the fully qualified name of the file given the IX'th 
        -- path entry, the file system separator and the name of the file passed to 
        -- this routine for checking. 
        -- 
        path_filename = path_list[ix] & filesys:SLASH & filename 
         
        -- 
        -- Now we need to check to see if the above exists and if so we return 
        -- the fully qualified name of the file to the caller. 
        -- 
        if filesys:file_exists(path_filename) then 
            return path_filename 
        end if 
    end for 
     
    -- 
    -- Finally, if we reach this point, then the file was not found in any of the 
    -- paths specified, and thus we return an empty string so that the caller 
    -- can determine that the file was not located. 
    return "" 
end function 
 
 
printf(1, "%s\n", { find_in_path("ldconfig", getenv("PATH"), "/sbin:/usr/sbin") } ) 
printf(1, "%s\n", { find_in_path("ls", getenv("PATH")) } ) 
printf(1, "%s\n", { find_in_path("xxx", getenv("PATH")) } ) 
 

On my Debian system, the first prints /sbin/ldconfig, the second /bin/ls and the third an empty string as it is (correctly) not located. Hope this can be of some help to you.