Write a UNIX command compsize that takes two files as input, compares their size

Question

Write a UNIX command compsize that takes two files as input, compares their sizes and determines which fie has bigger size than the other by printing out a message: “file1 is greater than file2.”

please write full C lanugae code using unix command and use command line argument.

struct stat {

               dev_t     st_dev;                    /* ID of device containing file */

               ino_t     st_ino;         /* inode number */

               mode_t    st_mode;               /* file type and mode */

               nlink_t   st_nlink;                 /* number of hard links */

               uid_t     st_uid;                    /* user ID of owner */

               gid_t     st_gid;                     /* group ID of owner */

               dev_t     st_rdev;                   /* device ID (if special file) */

               off_t     st_size;                     /* total size, in bytes */

               blksize_t st_blksize;             /* blocksize for filesystem I/O */

               blkcnt_t st_blocks;              /* number of 512B blocks allocated */

               ……..

           };

Explanation / Answer

stat.c

#include <sys/stat.h>
#include <acess/sys.h>

// === CODE ===
int stat(const char *path, struct stat *buf)
{
   int fd = _SysOpen(path, 0);
   if( !fd ) {
       // errno is set by _SysOpen
       return -1;
   }
  
   int rv = fstat(fd, buf);
   _SysClose(fd);
   return rv;
}

int lstat(const char *path, struct stat *buf)
{
   int fd = _SysOpen(path, OPENFLAG_NOLINK);
   if( !fd ) {
       // errno is set by _SysOpen
       return -1;
   }
  
   int rv = fstat(fd, buf);
   _SysClose(fd);
   return rv;
}

int fstat(int fd, struct stat *buf)
{
   t_sysFInfo   info;
  
   int rv = _SysFInfo(fd, &info, 0);
   if( rv == -1 ) {
       return -1;
   }

   _SysDebug("fstat(fd=%i,buf=%p)", fd, buf);

   // TODO: Populate buf
   buf->st_dev = info.mount;
   buf->st_ino = info.inode;
   if( info.flags & FILEFLAG_SYMLINK )
       buf->st_mode = S_IFLNK;
   else if( info.flags & FILEFLAG_DIRECTORY )
       buf->st_mode = S_IFDIR;
   else
       buf->st_mode = S_IFREG;
   // TODO: User modes (assume 660)
   buf->st_mode |= 0660;
   buf->st_nlink = 1;
   buf->st_uid = info.uid;
   buf->st_gid = info.gid;
   buf->st_rdev = NULL;
   buf->st_size = info.size;
   buf->st_blksize = 512;
   buf->st_blocks = (info.size+511)/512;
   buf->st_atime = info.atime;
   buf->st_mtime = info.mtime;
   buf->st_ctime = info.ctime;
  
   return 0;
}

stat.h

#ifndef _SYS_STAT_H_
#define _SYS_STAT_H_

#include <stdint.h>
#include "sys/types.h"   // off_t

#ifdef __cplusplus
extern "C" {
#endif

typedef void   *dev_t;   /* TODO: How to identify a device with Acess */
typedef uint64_t   ino_t;
typedef unsigned int   blksize_t;
typedef uint64_t   blkcnt_t;
typedef unsigned int   nlink_t;
typedef uint32_t   mode_t;

#define   S_IFMT       0170000   /* type of file */
#define       S_IFDIR   0040000   /* directory */
#define       S_IFCHR   0020000   /* character special */
#define       S_IFBLK   0060000   /* block special */
#define       S_IFREG   0100000   /* regular */
#define       S_IFLNK   0120000   /* symbolic link */
#define       S_IFSOCK   0140000   /* socket */
#define       S_IFIFO   0010000   /* fifo */

#define S_ISDIR(mode)   (((mode) & S_IFMT) == S_IFDIR)
#define S_ISREG(mode)   (((mode) & S_IFMT) == S_IFREG)
#define S_ISCHR(mode)   (((mode) & S_IFMT) == S_IFCHR)

struct stat
{
   dev_t     st_dev;     /* ID of device containing file */
   ino_t     st_ino;     /* inode number */
   mode_t    st_mode;    /* protection */
   nlink_t   st_nlink;   /* number of hard links */
   uid_t     st_uid;     /* user ID of owner */
   gid_t     st_gid;     /* group ID of owner */
   dev_t     st_rdev;    /* device ID (if special file) */
   off_t     st_size;    /* total size, in bytes */
   blksize_t st_blksize; /* blocksize for file system I/O */
   blkcnt_t st_blocks; /* number of 512B blocks allocated */
   time_t    st_atime;   /* time of last access */
   time_t    st_mtime;   /* time of last modification */
   time_t    st_ctime;   /* time of last status change */
};

extern int stat(const char *path, struct stat *buf);
extern int lstat(const char *path, struct stat *buf);
extern int fstat(int fd, struct stat *buf);
extern int mkdir(const char *pathname, mode_t mode);

#ifdef __cplusplus
}
#endif

#endif

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