Horodinca Mihai A2 MyTr

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <linux/limits.h>
#include <sys/stat.h>
#include <sys/types.h>

int main(int argc, char *argv[])
{
  struct stat st, oldmods;

  int fd_intrare, fd_iesire;
  char cmd;

  if (argc < 5)
  {
    printf("nr insuficient de argumente");
    exit(1);
  }

  if (-1 == (fd_intrarea = open(argv[1], O_RDONLY)))
  {
    perror("Eroare la deschiderea fisierului de intrare");
    exit(2);
  }

  stat(argv[2], &oldmods);
  if (0 == access(argv[2], F_OK))
  {
    if (-1 == access(argv[2], W_OK))
    {
      printf("Vrei sa-i dai drept de scriere? y n");
      scanf(" %c", &cmd);
      if (cmd == 'n' || cmd == 'N'){
        exit(3);
      }
      else if (cmd == 'y' || cmd == 'Y')
      {
        chmod(argv[2], oldmods.st_mode | S_IRUSR | S_IWUSR);
      }
      else
      {
        printf("Daca nu pot scrie fisierul nu mai am ce face");
        exit(3);
      }
    }
    printf("Vrei sa il suprascrii? Y sau N?");
    scanf(" %c", &cmd);
    if (cmd == 'y' || cmd == 'Y')
    {
      fd_iesire = open(argv[2], O_WRONLY | O_TRUNC);
    }
    else
    {
      fd_iesire = open(argv[2], O_WRONLY | O_APPEND);
    }
  }
  else
      if (-1 == (fd_iesire = creat(argv[2], oldmods.st_mode | S_IWUSR | S_IRUSR)))
  {
    perror("Eroare la apelul creat");
    exit(3);
  }

  int codRead;
  char bufferIn[PATH_MAX], bufferOut[PATH_MAX];
  char *pBufferIn, *pBufferOut;

  while (0 != (codRead = read(fd_intrare, bufferIn, PATH_MAX)))
  {
    if (-1 == codRead)
    {
      perror("Eroare la apelul read");
      exit(4);
    }
    pBufferIn = bufferIn;
    pBufferOut = bufferOut;

    for (size_t i = 0; i < codRead; i++, pBufferIn++)
    {
      if (*pBufferIn == argv[3][0])
      {
        *pBufferOut = argv[4][0];
      }
      else
      {
        *pBufferOut = *pBufferIn;
      }
      pBufferOut++;
    }
    *pBufferOut = '\0';
    if (-1 == write(fd_iesire, bufferOut, strlen(bufferOut)))
    {
      perror("Eroare la apelul write");
      exit(5);
    }
  }
  if (close(fd_intrare) == -1)
    exit(6);
  if (close(fd_iesire) == -1)
    exit (7);
  printf("Done!");
  return 0;
}