execv failure

[blerina12]

Hello guys. I am working on the code below. I am trying to create my own shell. The code compiles without errors, but when I execute it though it doesn't output anything. I have tried it with /bin/ls as input and it doesn't work. Any suggestions?

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

int main(int argc, char **argv, char **envp)
{
        char line[50];
        int length = 50;
        int i = 0, j = 0, k = 0;
        system("clear");
        printf("[m_shell ] ");
        fgets(line, length, stdin);
        while(line[k] != '\0')
        {
                argv[i] = (char *)malloc(sizeof(char) * 11);
                while(line[k] != ' ')
                {
                  argv[i][j] = line[k];
                                k ++;
                                j ++;
                }
	      argv[i][j] = '\0';
                        j = 0;
                        k ++;
                        i ++;
        }
        execve(argv[0], argv, envp);
        return 0;
}

[gerard4143]

Shouldn't this end with a NULL

execve(argv[0], argv, envp, NULL);

Ooops my mistake.

[Salem]

You should declare your own argv, rather than trying to use the one passed in main.

Also, you'll need to make sure your last argv is NULL.

[abhimanipal]

while(line[k] != '\0')
        {
                argv[i] = (char *)malloc(sizeof(char) * 11);

/*
   while(line[k] != ' ')
   This should be 
          while(line[k]!= ' '&& line[k]!='\0')
   If you give the command of the type "/bin/ls , your loop keeps on 
   searching till it find the space character
*/

                {
                  argv[i][j] = line[k];
                                k ++;
                                j ++;
                }
	      argv[i][j] = '\0';
                        j = 0;
                        k ++;
                        i ++;
        }
        execve(argv[0], argv, envp);
        return 0;
}

Also why are you using the argv array to store the parameters. Why not make a separate array ?

[gerard4143]

Here's a good example:

http://www.yolinux.com/TUTORIALS/ForkExecProcesses.html

[blerina12]

Problem solved :) Thank you guys for your suggestions. I really appreciate your help :)