Question

6 Write a C program that asks the user to enter the fil he all its permissions in a readable format.) Also, the program prints the file contents to the standard output if the file is of a regular type. Use only Unix V/O functions. Do not use the O package nor C standard I/O functions. Save your source file as "lab07a.c" and include it in the report.

I need to rewrite this program using only RIO I/O functions on c

Answer 1

#include <stdio.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include<fcntl.h>

int main()

{

char fileName[20];

//declare a struct of type stat to fill in details of file

struct stat info;

int is_reg=0,fd;

char c;

  

//ask user to input file name

printf("Enter file name: ");

scanf("%s",fileName);

printf("FileName: %s\n",fileName);

//call stat function to populate struct info with details of file

stat(fileName,&info);

if(S_ISREG(info.st_mode)!=0)

{

is_reg=1;

printf("%s is a regular file\n",fileName);

}

if(S_ISDIR(info.st_mode)!=0)

{

printf("%s is a directory \n",fileName);

}

if(S_ISCHR(info.st_mode)!=0)

{

printf("%s is a character device \n",fileName);

}

if(S_ISBLK(info.st_mode)!=0)

{

printf("%s is a block device \n",fileName);

}

if(S_ISFIFO(info.st_mode)!=0)

{

printf("%s is a FIFO \n",fileName);

}

else if(S_ISLNK(info.st_mode)!=0)

{

printf("%s is a symbolic link \n",fileName);

}

/*else if(S_ISSOCK(info.st_mode)!=0)

{

printf("%s is a socket\n",fileName);

}*/

  

if(is_reg == 1)

{

//printf("%d\n",is_reg);

//open file for reading and display onto screen

fd = open(fileName, O_RDONLY);

if(fd < 0 )

{

perror("Read: ");

return -1;

}

while (read(fd, &c, 1) > 0)

{

printf("%c", c);

}

}

return 0;

}

---------------------------------------------------------------

//output

  

Enter file name: info.txt

FileName: info.txt   

info.txt is a regular file   

The field st_mtime is changed by file modifications, e.g. by mknod(2), truncate(2), utime(2) and write(2) (of more than zero bytes).   

Moreover, st_mtime of a directory is changed by the creation or deletion of files in that directory.   

The st_mtime field is not changed for changes in owner, group, hard link count, or mode.