[C] Could-Be-A-Path Checker

[flowjob]

Hey,
I'm working on a project right now,and have to do the following:

My program should execute scripts and commands. If there's no arg an interpreter is started,otherwise it should check if it is an file (check also if correct path),or a command.

To explain it better,here's pseudo-code:

Code: [Select]

/* Pseudo Code */
if is argv                                      /* Got arguments ? */
    if maybepath(argv) == True    /* Could be a path to a file */
        if realpath(argv) == True     /* Path does exist */
            runfile(argv)
        else
            print 'File does not exist'  /* Path does not exist */
    else
        runcmd(argv)                        /* No path -> is command -> run command */
else                                              /* Got no args -> run interpreter */
    runinterpreter()
But I don't have the faithest idea how I could check if the given argument COULD be a path.
Any idea?  (should work on linux and windows)

[s3my0n]

I don't really understand what you mean, I guess you want to check if the given argument is a file or a path?

Just do:

Code: [Select]

FILE *file;

if (!(file = fopen(argv[1], "r"))){
    if (pathexists(argv[1])
        do something;
else
    do something with the file;


[flowjob]

I know how to check if a file does exist...
I want to check if the path is valid (syntax,etc...), so the file COULD exist.

e.g.: (in Windows)
'C:\Windows\System32\cmd.exe'       (valid,exists)
'C:\Windows\SysX\cmd.exe'               (valid,doesn't exist)
'C:\\Windows\\System32\\cmd.exe'   (valid,exists)
'X:\\cmd.exe'                                      (valid,doesn't exist)
'X:\foo\\bar\cmd.exe'                         (not valid,doesn't exist)
'\Windows\System32\cmd.exe'          (not valid,doesn't exist)
'FOO:\Windows\System32\cmd.exe'  (not valid,doesn't exist)

[Kulverstukas]

why not try and create a folder in the "could-be-path" and see if it throws an exception or some error, then the path is not valid.

[ca0s]

Simplify.

Code: [Select]

if maybepath(argv) == True    /* Could be a path to a file */
        if realpath(argv) == True     /* Path does exist */
could be just

Code: [Select]

if fileexists(argv)
and its working would be the same.

[flowjob]

@Kulverstukas:
But when deleting the folder again,I won't know wich folders did not exist...

eg:
before 'C:\Users\Me\'
after 'C:\Users\Me\new\newtoo\'

I won't know if 'new' did already exist or not when I created the folder 'newtoo' in 'C:\Users\Me\new\' ...


@ca0s
Yes,but if the file does not exist,I won't know if the user just wrote something wrong (e.g. 'C:\Windows\Sys32\cmd.exe') or he typed a command.
Because if he just typed something wrong I want to prompt him that the path does not exist.
But also still be able to exec it as a command if the given arg is no valid path ('e.g. print 'hi') ...

[s3my0n]

Maybe you could look into stat() sd function:

Code: [Select]

struct stat st;
if(stat("/tmp",&st) == 0)
    printf(" /tmp is present\n");

I would just check for specific flags in argv. For example everything after "-e" flag is a command, but after a "-f" flag is a file, or "-d" for a directory.

[flowjob]

Ok,that's an idea, I'll check it out..