df.c

#include "internal.h"
#include <stdio.h>
#include <mntent.h>
#include <sys/stat.h>
#include <sys/vfs.h>

const char	df_usage[] = "df [filesystem ...]\n"
"\n"
"\tPrint the filesystem space used and space available.\n";


static int
df(const char * device, const char * mountPoint)
{
	struct statfs	s;
	long		blocks_used;
	long		blocks_percent_used;

	if ( statfs(mountPoint, &s) != 0 ) {
		perror(mountPoint);
		return 1;
	}
	
	if ( s.f_blocks > 0 ) {
		blocks_used = s.f_blocks - s.f_bfree;
		blocks_percent_used = (long)
		 (blocks_used * 100.0 / (blocks_used + s.f_bavail) + 0.5);

		printf(
		       "%-20s %9ld %9ld %9ld %3ld%% %s\n",
		       device,
		       (long)(s.f_blocks * (s.f_bsize / 1024.0)),
		       (long)((s.f_blocks - s.f_bfree)  * (s.f_bsize / 1024.0)),
		       (long)(s.f_bavail * (s.f_bsize / 1024.0)),
		       blocks_percent_used,
		       mountPoint);

	}

	return 0;
}

extern int
df_main(int argc, char * * argv)
{
	printf("%-20s %-14s %s %s %s %s\n", "Filesystem",
		"1k-blocks", "Used", "Available", "Use%", "Mounted on");

	if ( argc > 1 ) {
		struct mntent*	mountEntry;
		int		status;

		while ( argc > 1 ) {
			if ( (mountEntry = findMountPoint(argv[1], "/proc/mounts")) == 0 )
			{
				fprintf(stderr, "%s: can't find mount point.\n" ,argv[1]);
				return 1;
			}
			status = df(mountEntry->mnt_fsname, mountEntry->mnt_dir);
			if ( status != 0 )
				return status;
			argc--;
			argv++;
		}
		return 0;
	}
	else {
		FILE *		mountTable;
		struct mntent *	mountEntry;

		mountTable = setmntent("/proc/mounts", "r");
		if ( mountTable == 0) {
			perror("/proc/mounts");
			exit( FALSE);
		}

		while ( (mountEntry = getmntent (mountTable))) {
			int status=df(mountEntry->mnt_fsname ,mountEntry->mnt_dir);
			if (status)
				return status;
		}
		endmntent(mountTable);
	}
	
	return 0;
}




/*
 * Given a block device, find the mount table entry if that block device
 * is mounted.
 *
 * Given any other file (or directory), find the mount table entry for its
 * filesystem.
 */
extern struct mntent *
findMountPoint(const char* name, const char* table)
{
	struct stat	s;
	dev_t			mountDevice;
	FILE *			mountTable;
	struct mntent *	mountEntry;

	if ( stat(name, &s) != 0 )
		return 0;

	if ( (s.st_mode & S_IFMT) == S_IFBLK )
		mountDevice = s.st_rdev;
	else
		mountDevice = s.st_dev;

	
	if ( (mountTable = setmntent(table, "r")) == 0 )
		return 0;

	while ( (mountEntry = getmntent(mountTable)) != 0 ) {
		if ( strcmp(name, mountEntry->mnt_dir) == 0
		 || strcmp(name, mountEntry->mnt_fsname) == 0 )	/* String match. */
			break;
		if ( stat(mountEntry->mnt_fsname, &s) == 0
		 && s.st_rdev == mountDevice )	/* Match the device. */
				break;
		if ( stat(mountEntry->mnt_dir, &s) == 0
		 && s.st_dev == mountDevice )	/* Match the directory's mount point. */
			break;
	}
	endmntent(mountTable);
	return mountEntry;
}