Writing simple shell in C, compiles but won't run :(

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#define LINE_LEN      80
#define MAX_ARGS      64
#define MAX_ARG_LEN   16
#define MAX_PATHS     64
#define MAX_PATH_LEN  96
#define DELIM         " *.,\t\n"
 
#ifndef NULL
#define NULL ...
#endif
 
struct command_t {
  char *name;
  int  argc;
  char *argv[MAX_ARGS]; };
 
char *lookupPath(char **, char **);
int  parseCommand(char *, struct command_t *);
int  parsePath(char **);
void printPrompt();
void readCommand(char *);
 
/******************************************************************/
 
void printPrompt() {
  /* This code simply prints the shell prompt to standard out */
  char prompt[] = "jSh > ";
  printf("%s",prompt);
}
 
/******************************************************************/
 
void readCommand(char *buffer) {
  /* This code reads the entire command line into the buffer */
  fgets(buffer,LINE_LEN,stdin);
}
 
/******************************************************************/
 
int parsePath(char *dirs[]) {
  /* This function reads the PATH variable for the environment and
     then builds an array of all the directories in PATH */
  char *pathEnvVar;
  char *thePath;
  char *tmp;
  int i;
  int k;
 
  for(i=0; i<MAX_PATHS; i++)
    dirs[i] = NULL;
  pathEnvVar = (char *) getenv("PATH");
  if (pathEnvVar == NULL)
    return 0;
 
  thePath = (char *) malloc(strlen(pathEnvVar) + 1);
  strcpy(thePath, pathEnvVar);
 
  /* Parse thePath and construct dirs array while parsing*/
  for(tmp=strtok(thePath,":"); tmp!=NULL; strtok(NULL,":")) {
    dirs[k] = malloc(strlen(tmp)+1);
 
    /* Need to break out if k is NULL */
    if (dirs[k] == NULL)
      break;
 
    strcpy(dirs[k],tmp);
    k = k+1;
  }
 
  /* Return array size */
  return k;
}
 
/******************************************************************/
 
char *lookupPath(char **argv, char **dirs) {
  /* This function searches for program names within dirs */
  char *tmp;
  char *result;
  int i;
 
  /* Base case, see if file name is absolute path name */
  if(*argv[0] == '/') {
    result = argv[0];
    return result;
  }
 
  /* Look in PATH directories using access() to check for file */
  for(i=0;i<MAX_PATHS;i++) {
    if(dirs[i] == NULL)
      continue;
    /* Construct string for full PATH name */
    tmp = (char *) malloc(MAX_PATH_LEN*20);
    strcpy(tmp,dirs[i]);
    strncat(tmp,"/",MAX_PATH_LEN);
    strncat(tmp,argv[0],MAX_PATH_LEN);
 
    /* Check to see if file is in PATH and is executable */
    if(access(dirs[i],X_OK) == 0) {
      result = tmp;
      return result;
    }
  }
  
  /* Account for file not being found in any directories */
  fprintf(stderr,"%s: command not found\n",argv[0]);
  return NULL;
}
 
/******************************************************************/
 
int parseCommand(char *cLine, struct command_t *cmd) {
  /* parses a command from standard input and creates a command struct */
  int argc;
  int count;
  char **clPtr;
  clPtr = &cLine;
  argc  = 0;
 
  /* Need to fill up argv[] with all of the tokens */
  cmd->argv[argc] = (char *) malloc(MAX_ARG_LEN);
  while((cmd->argv[argc] = strsep(clPtr,DELIM)) != NULL) {
    cmd->argv[++argc] = (char *) malloc(MAX_ARG_LEN);
  }
 
  /* need to decrement argc to reflect actual # of command args */
  cmd->argc = argc-1;
 
  /* create memory for name of command to be called, and store it in name */
  cmd->name = (char *) malloc(sizeof(cmd->argv[0]));
  strcpy(cmd->name,cmd->argv[0]);
 
  /* test for exit condition */
  if(strncasecmp(cmd->name,"exit",4)==0) {
    exit(0);
  }
 
  /* for testing purposes */
  printf("The command \"%s\" has %d argument(s)\n", cmd->name,cmd->argc);
  printf("argv0 = %s\n",cmd->argv[0]);
  for(count=0;count<argc;++count) {
    printf("argv[%d] = %s\n",count,cmd->argv[count]);
  }
 
  return 1;
}
 
/******************************************************************/
 
int main() {
  /* TEST */
  printf("inside main");
 
  char *pathv[MAX_PATHS];
  char commandLine[LINE_LEN];
  struct command_t command;
  int chPID;
  int status;
  pid_t childPID;
 
  /* TEST */
  printf("almost to parsePath()");
 
  /* Get all the PATH directories */
  parsePath(pathv);
 
  /* TEST */
  printf("got to parsePath()");
 
  /* loop to accept lines from standard input and parse them */
  while(1) {
    printPrompt();
    readCommand(commandLine);
    parseCommand(commandLine, &command);
    command.argv[command.argc] = NULL;
 
    /* Get the full pathname for the file */
    command.name = lookupPath(command.argv, pathv);
    if(command.name == NULL) {
      fprintf(stderr,"command \"%s\" unknown",command.name);
      continue;
    }
 
  /* Create child and execute the command */
    if((chPID = fork()) == 0) {
      printf("Child executing: %s\n", command.name);
      execvp(command.name, command.argv);
    }
 
  /* Wait for the child to terminate */
    printf("Parent waiting for child to terminate\n");
    childPID = wait(&status);
    /* Free dynamic storage in command structure */
    free(command.name);
  }
 
/* Shell termination */
  return 0;
}