/* vi: set sw=4 ts=4: */
/*
 * df.c - report free disk space.
 *
 * Implemented roughly according to SUSv3:
 * http://www.opengroup.org/onlinepubs/009695399/utilities/df.html
 *
 * usage: df [-k] [-P|-t] [file...]
 */

#include "toys.h"

static void show_mt(struct mtab_list *mt)
{
	int len;
	long size, used, avail, percent;
	uint64_t block;

	// Return if it wasn't found (should never happen, but with /etc/mtab...)
	if (!mt) return;

	// If we have -t, skip other filesystem types
	if (toy.df.fstype) {
		struct arg_list *al;

		for (al = toy.df.fstype; al; al = al->next) {
			if (!strcmp(mt->type, al->arg)) break;
		}
		if (!al) return;
	}

	// If we don't have -a, skip synthetic filesystems
	if (!(toys.optflags & 1) && !mt->statvfs.f_blocks) return;

	// Figure out how much total/used/free space this filesystem has,
	// forcing 64-bit math because filesystems are big now.
	block = mt->statvfs.f_bsize ? : 1;
	size = (long)((block * mt->statvfs.f_blocks) / toy.df.units);
	used = (long)((block * (mt->statvfs.f_blocks-mt->statvfs.f_bfree))
			/ toy.df.units);
	avail = (long)((block
				* (getuid() ? mt->statvfs.f_bavail : mt->statvfs.f_bfree))
			/ toy.df.units);
	percent = size ? 100-(long)((100*(uint64_t)avail)/size) : 0;

	// Figure out appropriate spacing
	len = 25 - strlen(mt->device);
	if (len < 1) len = 1;
	if (CFG_DF_PEDANTIC && (toys.optflags & 8)) {
		printf("%s %ld %ld %ld %ld%% %s\n", mt->device, size, used, avail,
				percent, mt->dir);
	} else {
		printf("%s% *ld % 10ld % 9ld % 3ld%% %s\n",mt->device, len,
			size, used, avail, percent, mt->dir);
	}
}

void df_main(void)
{
	struct mtab_list *mt, *mt2, *mtlist;

	// Handle -P and -k
	toy.df.units = 1024;
	if (CFG_DF_PEDANTIC && (toys.optflags & 8)) {
		// Units are 512 bytes if you select "pedantic" without "kilobytes".
		if ((toys.optflags&3) == 1) toy.df.units = 512;
		printf("Filesystem %ld-blocks Used Available Capacity Mounted on\n",
			toy.df.units);
	} else puts("Filesystem\t1K-blocks\tUsed Available Use% Mounted on");

	mtlist = getmountlist(1);

	// If we have a list of filesystems on the command line, loop through them.
	if (*toys.optargs) {
		char **next;

		for(next = toys.optargs; *next; next++) {
			struct stat st;

			// Stat it (complain if we can't).
			if(stat(*next, &st)) {
				perror_msg("`%s'", *next);
				toys.exitval = 1;
				continue;
			}

			// Find and display this filesystem.  Use _last_ hit in case of
			// -- bind mounts.
			mt2 = NULL;
			for (mt = mtlist; mt; mt = mt->next)
				if (st.st_dev == mt->stat.st_dev) mt2 = mt;
			show_mt(mt2);
		}
	} else {
		// Get and loop through mount list.

		for (mt = mtlist; mt; mt = mt->next) {
			struct mtab_list *mt2, *mt3;

			if (!mt->stat.st_dev) continue;

			// Filter out overmounts.
			mt3 = mt;
			for (mt2 = mt->next; mt2; mt2 = mt2->next) {
				if (mt->stat.st_dev == mt2->stat.st_dev) {
					// For --bind mounts, take last match
					if (!strcmp(mt->device, mt2->device)) mt3 = mt2;
					// Filter out overmounts
					mt2->stat.st_dev = 0;
				}
			}
			show_mt(mt3);
		}
	}

	if (CFG_TOYBOX_FREE) llist_free(mtlist, NULL);
}