fg_bg.c

#include "prototype.h"

extern struct utsname UNAME;
extern char* SYSTEM_NAME;
extern char HOME[500005];
extern char* USER;
extern char PWD_ABS_NAME[500005];
extern char PWD_NAME[500005];
extern DIR* PWD;
extern char* cmd;
extern int num_built_in;
extern char children_name[100000][51];
extern pid_t bg_children_PIDs[1000];
extern int bg_num_children;
extern pid_t currentChildPID;
extern pid_t startShellPID;
extern volatile sig_atomic_t run_clock;

void fg(int jobN)
{
  int* status;
  if(jobN > bg_num_children)
  {
    fprintf(stderr, "Specified job does not exist\n");
    return;
  }
  else
  {
    currentChildPID = bg_children_PIDs[jobN-1];
    waitpid(currentChildPID, status, WUNTRACED);
  }
}

void bg(int jobN)
{
  if(jobN > bg_num_children)
  {
    fprintf(stderr, "Specified job does not exist\n");
    return;
  }
  else
  {
    kill(bg_children_PIDs[jobN-1], SIGCONT);
  }
}