#include <stdio.h>
#include <string.h>
#include <unistd.h> /* for unix system interfaces calls */
#include <fcntl.h> /* for O_RDONLY and such */
#include <sys/stat.h>  /* for the stat() function and struct stat*/
#include <sys/types.h> /* for dev_t, S_IFMT et al */
#include <dirent.h> /* portable interface to implementation specifics */

#define MAX_PATH 1024

void fsize(char*);
void dirwalk(char *, void (*fcn)(char *));

/* print file sizes */
int main(int argc, char *argv[]) {
     
     if (argc == 1)
	  fsize(".");
     else
	  while (--argc > 0)
	       fsize(*++argv);
     return 0;
}

/* fsize: print size of file "name" */
void fsize(char *name) {
     struct stat stbuf;

     if (stat(name, &stbuf) == -1) {
	  fprintf(stderr, "fsize: can't access %s\n", name);
	  return;
     }
     if ((stbuf.st_mode & S_IFMT) == S_IFDIR)
	  dirwalk(name, fsize);
     printf("%8ld %s %8d:%d -- %d\n", stbuf.st_size, name, stbuf.st_uid, stbuf.st_gid,
	    (int) stbuf.st_atime);
}

/* dirwalk: apply fcn to all files in dir */
void dirwalk(char *dir, void (*fcn)(char *)) {
     char name[MAX_PATH];
     struct dirent *dp;
     DIR *dfd;

     if ((dfd = opendir(dir)) == NULL) {
	  fprintf(stderr, "dirwalk: can't open %s\n", dir);
	  return;
     }
     while ((dp = readdir(dfd)) != NULL) {
	  if (strcmp(dp->d_name, ".") == 0
	      || strcmp(dp->d_name, "..") == 0)
	       continue;
	  if (strlen(dir)+strlen(dp->d_name)+2 > sizeof(name))
	       fprintf(stderr, "dirwalk: name %s/%s too long\n",
		       dir, dp->d_name);
	  else {
	       sprintf(name, "%s/%s", dir, dp->d_name);
	       (*fcn)(name);
	  }
     }
     closedir(dfd);
}