Thread: Need help, please - very strange behavior

First of all, thank you for trying to help. I've tried running this on 3 different computer running 3 different Linux distros with the same results. As I stated in my post, I am doing a system() call to the file that gets created.

The paths are all stated as 'system(./filea.sh)'. I've tried this with the program in different places, including a usb flash drive, using desktop icons, and clicking directly on the program icon. All scenarios produce the same results. I've tried running this in a terminal from different directories and as long as a terminal is involved in starting the program, it runs without problems.

I've created desktop icons, with full path names, including working directory. Same problem. If I run it through GDB, it works right, since I'm using a terminal to run GDB.

I'm wondering why, a terminal makes a difference. The other part of the program that uses the exact same functions to create that shell file and run it, works no matter where I start the program from.

Here's another clue. The part of the program that downloads the one file from the remote computer, immediately tries to open that downloaded file. It bombs, since that file is not actually downloaded yet. In fact, it looks like that shell file that downloads the one file doesn't even run. However, if I use the other part of the program that does work, and it downloads the file correctly, then run the part that doesn't work properly, it works, since the file is now in it's directory to work on.

Here is the code that is called from both locations. One works, the other section of the program that calls it, doesn't. The 'get_kod.sh' file never runs if called the program is started from either clicking on the program to run or started from an icon. BUT, it works if run from a terminal. In the non-working part of the program, it never reaches the openssl part of the program and never downloads anything from the remote host.

Code:

  char text[250];
  strcpy(text,"#!/usr/bin/expect\n");
  strcat(text,"set timeout 30\n");
  strcat(text,"set user [lindex $argv 0]\n");
  strcat(text,"spawn scp ");
  strcat(text,user);
  strcat(text,"@");
  strcat(text,ip);
  strcat(text,":/home/");
  strcat(text,user);
  strcat(text,"/");
  strcat(text,kod_to_get);
  strcat(text," ./\n");
  strcat(text,"expect \"");
  strcat(text,user);
  strcat(text,"@");
  strcat(text,ip);
  strcat(text,"'s password:\"\n");
  strcat(text,"send \"");
  strcat(text,pw);
  strcat(text,"\\r");
  strcat(text,"\"\n");
  strcat(text,"interact\n");
  
//  g_print("scp text: %s \n",text); 
    
    FILE *fptr;

  // Open file for writing
  if ((fptr = fopen ("get_kod.sh","w"))==NULL)
    {
    printf ("Cannot open file\n");
    exit (1);
    }
    fputs(text,fptr);

  if(fclose(fptr))
      printf("File close error\n");

  system("chmod +x get_kod.sh");
 
  int ret;
  ret = WEXITSTATUS(system("./get_kod.sh"));
  
//  gtk_label_set_label((GtkLabel *)label_status, ret);
 
  // Setup command to decrypt binkod file
  strcpy(text,"openssl enc -aes-256-cbc -d -pass pass:");
  strcat(text,ukey);
  strcat(text," -in ");
  strcat(text,kod_to_get);
  strcat(text," -out kod.txt");

  ret = WEXITSTATUS(system(text));

Is it perhaps putting it in a different directory?

Does the program complete if you comment out the offending system() call...

I ran my program from the icon in order to have it create the 'getkod' file. Here's what in the getkod file;

Code:

#!/usr/bin/expect
set timeout 30
set user [lindex $argv 0]
spawn scp [email protected]:/home/abc/0925.key ./
expect "[email protected]'s password:"
send "windtalkabc\r"
interact

I then wrote a very simple program to execute that file..below;

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main (int argc, char *argv[])
{
  int ret;
  ret = WEXITSTATUS(system("./getkod"));
  if (!ret)
  {
    system("touch fail");
  }
  return 0;
}

If I run this little program from an icon, even with all the directories set correctly, the file getkod never get's executed. If I run it from a terminal, it gets executed.

What am I missing here ????

The program and file are in the same directory.

No. But I have tried using root, with same results. The 'getkod' file gets created with owner: me, group: root. It set as executable for all.
I've changed the name of the program to run inside the system call and it works. e.g. system("firefox").

What is so different from running my little program from an icon as opposed to a terminal? It's accessing that directory because it creates that 'fail' file. the getkod file is getting created in the same directory as everything else.

Is there some way that I can even tell if the system is 'trying' to execute the 'getkod' file? It runs too fast to check the PID. The return code says that it didn't execute (I may misunderstand exactly what the return code is telling me). e.g. it didn't run the program or it didn't run it completely, etc.

I've narrowed this down to the very basics and have eliminated almost everything but the actual system call. As I mention, that works because it can run other programs.

quzah,

Brilliant!

Are you ready for this? I put a 'sleep 20' statement as the last line in the file 'getkod'. It works!

I'm going to try other values.

Why? What do you think is happening? What does that have to do with running in a terminal or not? I'm confused...

You're considering a return value of 0 from system() to be a failure (i.e., if(!ret) touch fail); but this goes against Unix semantics. A return value of 0 typically means success.

Of course this can't explain why things work one way and don't the other (at best it just flips them), but I think it's still worth pointing out.

Thanks, I knew that. I guess I've been too rattled lately, trying to figure out this. I don't know what I was thinking. The test should have been without the exclamation point (not).

It still doesn't make sense to me what is happening here. I also thought it might be that there was no end of line or linefeed on the last line, but that wasn't the case. 'Sleep 1' works as the last line in the getkod file, but for the life of me, I can't figure out what that has to do with not running in a terminal. 'Sleep 0' does not work, so it doesn't have anything to do with just having another statement in that file. It actually has to sleep for some time period. Why would running it in a terminal allow that to happen automatically?

Thanks Quzah for the direction to go in to solve this nasty problem. And, thanks for everyone else that has tried to help.