Trouble in passing char * vector argument

[fkpac]

Hi everybody. I am trying to simulate a shell. So what I do is checking of having the parameters from standard input, suc as "/bin/ls -l /home/france/Documents", and then passing them to function execute, which at some point calls execvp(argv[0],argv)
The problem is that I don't succeed in using these arguments, while if I call execvp(paramList[0],paramList) it works!!!! Where paramList is exactly what I would put on standard input, but defined statically.

The code::

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

#define MAXARG 20

int getargs (int * pargc,char * argv[]);
static void execute (int argc, char *argv[]);
void copia(char * argv[],int argc,char * temp);

int main (void) {
  int i=0;
  char * argv [MAXARG]; int argc;
  if (1) {          
    printf("ready: ");         
    if (getargs(&argc,argv)!= -1) {
      printf("Andato tutto bene\n");

      while(strcmp(argv[i],"NULL")!=0)
	{
	  printf("argv[%d] è: %s\n",i,argv[i]);
	  i++;
	}

      execute(argc, argv);
      
    }
    else
      printf("Oops!\n");
  }
  return(0);
}




int getargs (int * argc,char * argv[])
 {
   int i=0;
   char * str=malloc(MAXARG*sizeof(char));
   scanf("%s",str);
   do{
     argv[i]=malloc(MAXARG*sizeof(char *));
     strcpy(argv[i],str);
     i++;
     scanf("%s",str);
   } while (strcmp(str,"NULL")!=0);
   argv[i]=malloc(MAXARG*sizeof(char *));
   strcpy(argv[i],str);
   *argc=i;
   return(0);
 }


static void execute (int argc, char *argv[])
{   
  int i=0;
  char *const paramList[] = 
   {"/bin/ls", "-l", "/home/france/Documents", "NULL"};
  pid_t pid;

      while(strcmp(paramList[i],"NULL")!=0)
	{
	  printf("paramList[%d] è: %s\n",i,paramList[i]);
	  i++;
	}
      i=0;
      while(strcmp(argv[i],"NULL")!=0)
	{
	  printf("argv[%d] è: %s\n",i,argv[i]);
	  i++;
	}
  switch(pid=fork())
    {
    case -1: 
      {
      perror ("Cannot fork");
      break;
      }
    case 0:
      {
	execvp(argv[0],argv);
	perror("Cannot exec");
	break;
      }
    default: exit(0);
    }
}

[theNbomr]

Without examining the logic of your program, I see that you are using the literal string "NULL", which I suppose you think is a NULL pointer. It isn't. The symbol NULL is probably what you want.
--- rod.

[Rubberman]

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