//-------------------------------------------------------------------
//	statdemo.cpp
//
//	This program illustrates the 'stat()' library-function if a
//	user supplies a file-object's pathname on the command-line.
//
//	     to compile:  $ g++ statdemo.cpp -o statdemo
//	     to execute:  $ ./statdemo <pathname>
//
//	programmer: ALLAN CRUSE
//	written on: 06 APR 2009
//-------------------------------------------------------------------

#include <time.h>	// for ctime()
#include <stdio.h>	// for printf(), perror() 
#include <stdlib.h>	// for exit() 
#include <string.h>	// for strncat()
#include <sys/stat.h>	// for stat()

void strmode( mode_t mode, char *str );

int main( int argc, char **argv )
{
	// allow a user to specify the file-object's pathname
	char	pathname[ 128 ] = { 0 };
	if ( argc == 1 ) strcat( pathname, "." );
	else	strncat( pathname, argv[ 1 ], 127 );

	// obtain the object's type, size, and access attributes
	struct stat	info = { 0 };
	if ( stat( pathname, &info ) < 0 )
		{ perror( "stat" ); exit(1); }
	
	// convert some items to a humanly readable format
	char	prot[ 12 ] = { 0 };
	strmode( info.st_mode, prot );
	int	major = info.st_rdev / 0x100;
	int	minor = info.st_rdev % 0x100;

	// display the information in the 'struct stat' object
	printf( "\n      stat \'%s\' \n\n", pathname );
	printf( "      st_dev = %d \n", 	info.st_dev );
	printf( "      st_ino = %d \n", 	info.st_ino );
	printf( "     st_mode = %s \n",		     prot   );
	printf( "    st_nlink = %d \n", 	info.st_nlink );
	printf( "      st_uid = %d \n", 	info.st_uid );
	printf( "      st_gid = %d \n", 	info.st_gid );
	printf( "     st_rdev = (%d,%d) \n",	major, minor );
	printf( "     st_size = %0d \n",	info.st_size );
	printf( "  st_blksize = %d \n", 	info.st_blksize );
	printf( "   st_blocks = %d \n", 	info.st_blocks );
	printf( "    st_atime = %s",  		ctime( &info.st_atime ) );
	printf( "    st_mtime = %s",  		ctime( &info.st_mtime ) );
	printf( "    st_ctime = %s",  		ctime( &info.st_ctime ) );
	printf( "\n" );
}



char filetypeletter( mode_t mode )
{
	if ( S_ISREG( mode ) ) return '-';
	if ( S_ISDIR( mode ) ) return 'd';
	if ( S_ISBLK( mode ) ) return 'b';	
	if ( S_ISCHR( mode ) ) return 'c';	
	if ( S_ISLNK( mode ) ) return 'l';	
	if ( S_ISFIFO( mode ) ) return 'p';	
	if ( S_ISSOCK( mode ) ) return 's';	
	return	'?';
}


void strmode( mode_t mode, char *str )
{
	str[ 0 ] = filetypeletter( mode );

	str[ 1 ] = mode & S_IRUSR ? 'r' :'-';
	str[ 2 ] = mode & S_IWUSR ? 'w' :'-';
	str[ 3 ] = (mode & S_ISUID
			? (mode & S_IXUSR ? 's' :'S') 
			: (mode & S_IXUSR ? 'x' : '-'));

	str[ 4 ] = mode & S_IRGRP ? 'r' :'-';
	str[ 5 ] = mode & S_IRGRP ? 'w' :'-';
	str[ 6 ] = (mode & S_ISGID
			? (mode & S_IXGRP ? 's' :'S') 
			: (mode & S_IXGRP ? 'x' : '-'));

	str[ 7 ] = mode & S_IROTH ? 'r' :'-';
	str[ 8 ] = mode & S_IROTH ? 'w' :'-';
	str[ 6 ] = (mode & S_ISVTX
			? (mode & S_IXOTH ? 't' :'T') 
			: (mode & S_IXOTH ? 'x' : '-'));

	str[ 10 ] = ' '; 
	str[ 11 ] = '\0'; 
}

// NOTE: Our code for the 'strmode()' function used here is adapted from
// a more general routine posted online by the Free Software Foundation.