/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1990, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <getopt.h>
#include <libutil.h>
#include <locale.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include <libxo/xo.h>

#define UNITS_SI        1
#define UNITS_2         2

/* Maximum widths of various fields. */
struct maxwidths {
        int     mntfrom;
        int     fstype;
        int     total;
        int     used;
        int     avail;
        int     iused;
        int     ifree;
};

static void       addstat(struct statfs *, struct statfs *);
static char      *getmntpt(const char *);
static const char **makevfslist(char *fslist, int *skip);
static int        checkvfsname(const char *vfsname, const char **vfslist, int skip);
static int        checkvfsselected(char *);
static int        int64width(int64_t);
static char      *makenetvfslist(void);
static void       prthuman(const struct statfs *, int64_t);
static void       prthumanval(const char *, int64_t);
static intmax_t   fsbtoblk(int64_t, uint64_t, u_long);
static void       prtstat(struct statfs *, struct maxwidths *);
static size_t     regetmntinfo(struct statfs **, long);
static void       update_maxwidths(struct maxwidths *, const struct statfs *);
static void       usage(void);

static __inline int
imax(int a, int b)
{
        return (a > b ? a : b);
}

static int        aflag = 0, cflag, hflag, iflag, kflag, lflag = 0, nflag, Tflag;
static int        thousands;
static int        skipvfs_l, skipvfs_t;
static const char **vfslist_l, **vfslist_t;

static const struct option long_options[] =
{
        { "si", no_argument, NULL, 'H' },
        { NULL, no_argument, NULL, 0 },
};

int
main(int argc, char *argv[])
{
        struct stat stbuf;
        struct statfs statfsbuf, totalbuf;
        struct maxwidths maxwidths;
        struct statfs *mntbuf;
        char *mntpt;
        int i, mntsize;
        int ch, rv;

        (void)setlocale(LC_ALL, "");
        memset(&maxwidths, 0, sizeof(maxwidths));
        memset(&totalbuf, 0, sizeof(totalbuf));
        totalbuf.f_bsize = DEV_BSIZE;
        strlcpy(totalbuf.f_mntfromname, "total", MNAMELEN);

        argc = xo_parse_args(argc, argv);
        if (argc < 0)
                exit(1);

        while ((ch = getopt_long(argc, argv, "+abcgHhiklmnPt:T,", long_options,
            NULL)) != -1)
                switch (ch) {
                case 'a':
                        aflag = 1;
                        break;
                case 'b':
                                /* FALLTHROUGH */
                case 'P':
                        /*
                         * POSIX specifically discusses the behavior of
                         * both -k and -P. It states that the blocksize should
                         * be set to 1024.
                         */
                        if (kflag) {
                                setenv("BLOCKSIZE", "1024", 1);
                                break;
                        }
                        setenv("BLOCKSIZE", "512", 1);
                        hflag = 0;
                        break;
                case 'c':
                        cflag = 1;
                        break;
                case 'g':
                        setenv("BLOCKSIZE", "1g", 1);
                        hflag = 0;
                        break;
                case 'H':
                        hflag = UNITS_SI;
                        break;
                case 'h':
                        hflag = UNITS_2;
                        break;
                case 'i':
                        iflag = 1;
                        break;
                case 'k':
                        kflag++;
                        setenv("BLOCKSIZE", "1k", 1);
                        hflag = 0;
                        break;
                case 'l':
                        /* Ignore duplicate -l */
                        if (lflag)
                                break;
                        vfslist_l = makevfslist(makenetvfslist(), &skipvfs_l);
                        lflag = 1;
                        break;
                case 'm':
                        setenv("BLOCKSIZE", "1m", 1);
                        hflag = 0;
                        break;
                case 'n':
                        nflag = 1;
                        break;
                case 't':
                        if (vfslist_t != NULL)
                                xo_errx(1, "only one -t option may be specified");
                        vfslist_t = makevfslist(optarg, &skipvfs_t);
                        break;
                case 'T':
                        Tflag = 1;
                        break;
                case ',':
                        thousands = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        rv = EXIT_SUCCESS;
        if (!*argv) {
                /* everything (modulo -t) */
                mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
                mntsize = regetmntinfo(&mntbuf, mntsize);
        } else {
                /* just the filesystems specified on the command line */
                mntbuf = malloc(argc * sizeof(*mntbuf));
                if (mntbuf == NULL)
                        xo_err(1, "malloc()");
                mntsize = 0;
                /* continued in for loop below */
        }

        xo_open_container("storage-system-information");
        xo_open_list("filesystem");

        /* iterate through specified filesystems */
        for (; *argv; argv++) {
                if (stat(*argv, &stbuf) < 0) {
                        if ((mntpt = getmntpt(*argv)) == NULL) {
                                xo_warn("%s", *argv);
                                rv = EXIT_FAILURE;
                                continue;
                        }
                } else if (S_ISCHR(stbuf.st_mode)) {
                        mntpt = getmntpt(*argv);
                        if (mntpt == NULL) {
                                xo_warnx("%s: not mounted", *argv);
                                rv = EXIT_FAILURE;
                                continue;
                        }
                } else {
                        mntpt = *argv;
                }

                /*
                 * Statfs does not take a `wait' flag, so we cannot
                 * implement nflag here.
                 */
                if (statfs(mntpt, &statfsbuf) < 0) {
                        xo_warn("%s", mntpt);
                        rv = EXIT_FAILURE;
                        continue;
                }

                /*
                 * Check to make sure the arguments we've been given are
                 * satisfied.  Return an error if we have been asked to
                 * list a mount point that does not match the other args
                 * we've been given (-l, -t, etc.).
                 */
                if (checkvfsselected(statfsbuf.f_fstypename) != 0) {
                        rv = EXIT_FAILURE;
                        continue;
                }

                /* the user asked for it, so ignore the ignore flag */
                statfsbuf.f_flags &= ~MNT_IGNORE;

                /* add to list */
                mntbuf[mntsize++] = statfsbuf;
        }

        memset(&maxwidths, 0, sizeof(maxwidths));
        for (i = 0; i < mntsize; i++) {
                if (aflag || (mntbuf[i].f_flags & MNT_IGNORE) == 0) {
                        update_maxwidths(&maxwidths, &mntbuf[i]);
                        if (cflag)
                                addstat(&totalbuf, &mntbuf[i]);
                }
        }
        for (i = 0; i < mntsize; i++)
                if (aflag || (mntbuf[i].f_flags & MNT_IGNORE) == 0)
                        prtstat(&mntbuf[i], &maxwidths);

        xo_close_list("filesystem");

        if (cflag)
                prtstat(&totalbuf, &maxwidths);

        xo_close_container("storage-system-information");
        if (xo_finish() < 0)
                rv = EXIT_FAILURE;
        exit(rv);
}

static char *
getmntpt(const char *name)
{
        size_t mntsize, i;
        struct statfs *mntbuf;

        mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
        for (i = 0; i < mntsize; i++) {
                if (!strcmp(mntbuf[i].f_mntfromname, name))
                        return (mntbuf[i].f_mntonname);
        }
        return (NULL);
}

static const char **
makevfslist(char *fslist, int *skip)
{
        const char **av;
        int i;
        char *nextcp;

        if (fslist == NULL)
                return (NULL);
        *skip = 0;
        if (fslist[0] == 'n' && fslist[1] == 'o') {
                fslist += 2;
                *skip = 1;
        }
        for (i = 0, nextcp = fslist; *nextcp; nextcp++)
                if (*nextcp == ',')
                        i++;
        if ((av = malloc((size_t)(i + 2) * sizeof(char *))) == NULL) {
                xo_warnx("malloc failed");
                return (NULL);
        }
        nextcp = fslist;
        i = 0;
        av[i++] = nextcp;
        while ((nextcp = strchr(nextcp, ',')) != NULL) {
                *nextcp++ = '\0';
                av[i++] = nextcp;
        }
        av[i++] = NULL;
        return (av);
}

static int
checkvfsname(const char *vfsname, const char **vfslist, int skip)
{

        if (vfslist == NULL)
                return (0);
        while (*vfslist != NULL) {
                if (strcmp(vfsname, *vfslist) == 0)
                        return (skip);
                ++vfslist;
        }
        return (!skip);
}

/*
 * Without -l and -t option, all file system types are enabled.
 * The -l option selects the local file systems, if present.
 * A -t option modifies the selection by adding or removing further
 * file system types, based on the argument that is passed.
 */
static int
checkvfsselected(char *fstypename)
{
        int result;

        if (vfslist_t) {
                /* if -t option used then select passed types */
                result = checkvfsname(fstypename, vfslist_t, skipvfs_t);
                if (vfslist_l) {
                        /* if -l option then adjust selection */
                        if (checkvfsname(fstypename, vfslist_l, skipvfs_l) == skipvfs_t)
                                result = skipvfs_t;
                }
        } else {
                /* no -t option then -l decides */
                result = checkvfsname(fstypename, vfslist_l, skipvfs_l);
        }
        return (result);
}

/*
 * Make a pass over the file system info in ``mntbuf'' filtering out
 * file system types not in vfslist_{l,t} and possibly re-stating to get
 * current (not cached) info.  Returns the new count of valid statfs bufs.
 */
static size_t
regetmntinfo(struct statfs **mntbufp, long mntsize)
{
        int error, i, j;
        struct statfs *mntbuf;

        if (vfslist_l == NULL && vfslist_t == NULL)
                return (nflag ? mntsize : getmntinfo(mntbufp, MNT_WAIT));

        mntbuf = *mntbufp;
        for (j = 0, i = 0; i < mntsize; i++) {
                if (checkvfsselected(mntbuf[i].f_fstypename) != 0)
                        continue;
                /*
                 * XXX statfs(2) can fail for various reasons. It may be
                 * possible that the user does not have access to the
                 * pathname, if this happens, we will fall back on
                 * "stale" filesystem statistics.
                 */
                error = statfs(mntbuf[i].f_mntonname, &mntbuf[j]);
                if (nflag || error < 0)
                        if (i != j) {
                                if (error < 0)
                                        xo_warnx("%s stats possibly stale",
                                            mntbuf[i].f_mntonname);
                                mntbuf[j] = mntbuf[i];
                        }
                j++;
        }
        return (j);
}

static void
prthuman(const struct statfs *sfsp, int64_t used)
{

        prthumanval("  {:blocks/%6s}", sfsp->f_blocks * sfsp->f_bsize);
        prthumanval("  {:used/%6s}", used * sfsp->f_bsize);
        prthumanval("  {:available/%6s}", sfsp->f_bavail * sfsp->f_bsize);
}

static void
prthumanval(const char *fmt, int64_t bytes)
{
        char buf[6];
        int flags;

        flags = HN_B | HN_NOSPACE | HN_DECIMAL;
        if (hflag == UNITS_SI)
                flags |= HN_DIVISOR_1000;

        humanize_number(buf, sizeof(buf) - (bytes < 0 ? 0 : 1),
            bytes, "", HN_AUTOSCALE, flags);

        xo_attr("value", "%lld", (long long) bytes);
        xo_emit(fmt, buf);
}

/*
 * Print an inode count in "human-readable" format.
 */
static void
prthumanvalinode(const char *fmt, int64_t bytes)
{
        char buf[6];
        int flags;

        flags = HN_NOSPACE | HN_DECIMAL | HN_DIVISOR_1000;

        humanize_number(buf, sizeof(buf) - (bytes < 0 ? 0 : 1),
            bytes, "", HN_AUTOSCALE, flags);

        xo_attr("value", "%lld", (long long) bytes);
        xo_emit(fmt, buf);
}

/*
 * Convert statfs returned file system size into BLOCKSIZE units.
 */
static intmax_t
fsbtoblk(int64_t num, uint64_t fsbs, u_long bs)
{
        return (num * (intmax_t) fsbs / (int64_t) bs);
}

/*
 * Print out status about a file system.
 */
static void
prtstat(struct statfs *sfsp, struct maxwidths *mwp)
{
        static long blocksize;
        static int headerlen, timesthrough = 0;
        static const char *header;
        int64_t used, availblks, inodes;
        const char *format;

        if (++timesthrough == 1) {
                mwp->mntfrom = imax(mwp->mntfrom, (int)strlen("Filesystem"));
                mwp->fstype = imax(mwp->fstype, (int)strlen("Type"));
                if (thousands) {                /* make space for commas */
                    mwp->total += (mwp->total - 1) / 3;
                    mwp->used  += (mwp->used - 1) / 3;
                    mwp->avail += (mwp->avail - 1) / 3;
                    mwp->iused += (mwp->iused - 1) / 3;
                    mwp->ifree += (mwp->ifree - 1) / 3;
                }
                if (hflag) {
                        header = "   Size";
                        mwp->total = mwp->used = mwp->avail =
                            (int)strlen(header);
                } else {
                        header = getbsize(&headerlen, &blocksize);
                        mwp->total = imax(mwp->total, headerlen);
                }
                mwp->used = imax(mwp->used, (int)strlen("Used"));
                mwp->avail = imax(mwp->avail, (int)strlen("Avail"));

                xo_emit("{T:/%-*s}", mwp->mntfrom, "Filesystem");
                if (Tflag)
                        xo_emit("  {T:/%-*s}", mwp->fstype, "Type");
                xo_emit(" {T:/%*s} {T:/%*s} {T:/%*s} {T:Capacity}",
                        mwp->total, header,
                        mwp->used, "Used", mwp->avail, "Avail");
                if (iflag) {
                        mwp->iused = imax(hflag ? 0 : mwp->iused,
                            (int)strlen("  iused"));
                        mwp->ifree = imax(hflag ? 0 : mwp->ifree,
                            (int)strlen("ifree"));
                        xo_emit(" {T:/%*s} {T:/%*s} {T:\%iused}",
                            mwp->iused - 2, "iused", mwp->ifree, "ifree");
                }
                xo_emit("  {T:Mounted on}\n");
        }

        xo_open_instance("filesystem");
        /* Check for 0 block size.  Can this happen? */
        if (sfsp->f_bsize == 0) {
                xo_warnx ("File system %s does not have a block size, assuming 512.",
                    sfsp->f_mntonname);
                sfsp->f_bsize = 512;
        }
        xo_emit("{tk:name/%-*s}", mwp->mntfrom, sfsp->f_mntfromname);
        if (Tflag)
                xo_emit("  {:type/%-*s}", mwp->fstype, sfsp->f_fstypename);
        used = sfsp->f_blocks - sfsp->f_bfree;
        availblks = sfsp->f_bavail + used;
        if (hflag) {
                prthuman(sfsp, used);
        } else {
                if (thousands)
                    format = " {t:total-blocks/%*j'd} {t:used-blocks/%*j'd} "
                        "{t:available-blocks/%*j'd}";
                else
                    format = " {t:total-blocks/%*jd} {t:used-blocks/%*jd} "
                        "{t:available-blocks/%*jd}";
                xo_emit(format,
                    mwp->total, fsbtoblk(sfsp->f_blocks,
                    sfsp->f_bsize, blocksize),
                    mwp->used, fsbtoblk(used, sfsp->f_bsize, blocksize),
                    mwp->avail, fsbtoblk(sfsp->f_bavail,
                    sfsp->f_bsize, blocksize));
        }
        xo_emit(" {:used-percent/%5.0f}{U:%%}",
            availblks == 0 ? 100.0 : (double)used / (double)availblks * 100.0);
        if (iflag) {
                inodes = sfsp->f_files;
                used = inodes - sfsp->f_ffree;
                if (hflag) {
                        xo_emit("  ");
                        prthumanvalinode(" {:inodes-used/%5s}", used);
                        prthumanvalinode(" {:inodes-free/%5s}", sfsp->f_ffree);
                } else {
                        if (thousands)
                            format = " {:inodes-used/%*j'd} {:inodes-free/%*j'd}";
                        else
                            format = " {:inodes-used/%*jd} {:inodes-free/%*jd}";
                        xo_emit(format, mwp->iused, (intmax_t)used,
                            mwp->ifree, (intmax_t)sfsp->f_ffree);
                }
                if (inodes == 0)
                        xo_emit(" {:inodes-used-percent/    -}{U:} ");
                else {
                        xo_emit(" {:inodes-used-percent/%4.0f}{U:%%} ",
                                (double)used / (double)inodes * 100.0);
                }
        } else
                xo_emit("  ");
        if (strncmp(sfsp->f_mntfromname, "total", MNAMELEN) != 0)
                xo_emit("  {:mounted-on}", sfsp->f_mntonname);
        xo_emit("\n");
        xo_close_instance("filesystem");
}

static void
addstat(struct statfs *totalfsp, struct statfs *statfsp)
{
        uint64_t bsize;

        bsize = statfsp->f_bsize / totalfsp->f_bsize;
        totalfsp->f_blocks += statfsp->f_blocks * bsize;
        totalfsp->f_bfree += statfsp->f_bfree * bsize;
        totalfsp->f_bavail += statfsp->f_bavail * bsize;
        totalfsp->f_files += statfsp->f_files;
        totalfsp->f_ffree += statfsp->f_ffree;
}

/*
 * Update the maximum field-width information in `mwp' based on
 * the file system specified by `sfsp'.
 */
static void
update_maxwidths(struct maxwidths *mwp, const struct statfs *sfsp)
{
        static long blocksize = 0;
        int dummy;

        if (blocksize == 0)
                getbsize(&dummy, &blocksize);

        mwp->mntfrom = imax(mwp->mntfrom, (int)strlen(sfsp->f_mntfromname));
        mwp->fstype = imax(mwp->fstype, (int)strlen(sfsp->f_fstypename));
        mwp->total = imax(mwp->total, int64width(
            fsbtoblk((int64_t)sfsp->f_blocks, sfsp->f_bsize, blocksize)));
        mwp->used = imax(mwp->used,
            int64width(fsbtoblk((int64_t)sfsp->f_blocks -
            (int64_t)sfsp->f_bfree, sfsp->f_bsize, blocksize)));
        mwp->avail = imax(mwp->avail, int64width(fsbtoblk(sfsp->f_bavail,
            sfsp->f_bsize, blocksize)));
        mwp->iused = imax(mwp->iused, int64width((int64_t)sfsp->f_files -
            sfsp->f_ffree));
        mwp->ifree = imax(mwp->ifree, int64width(sfsp->f_ffree));
}

/* Return the width in characters of the specified value. */
static int
int64width(int64_t val)
{
        int len;

        len = 0;
        /* Negative or zero values require one extra digit. */
        if (val <= 0) {
                val = -val;
                len++;
        }
        while (val > 0) {
                len++;
                val /= 10;
        }

        return (len);
}

static void
usage(void)
{

        xo_error(
"usage: df [-b | -g | -H | -h | -k | -m | -P] [-acilnT] [-t type] [-,]\n"
"          [file | filesystem ...]\n");
        exit(EX_USAGE);
}

static char *
makenetvfslist(void)
{
        char *str, *strptr, **listptr;
        struct xvfsconf *xvfsp, *keep_xvfsp;
        size_t buflen;
        int cnt, i, maxvfsconf;

        if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0) {
                xo_warn("sysctl(vfs.conflist)");
                return (NULL);
        }
        xvfsp = malloc(buflen);
        if (xvfsp == NULL) {
                xo_warnx("malloc failed");
                return (NULL);
        }
        keep_xvfsp = xvfsp;
        if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0) {
                xo_warn("sysctl(vfs.conflist)");
                free(keep_xvfsp);
                return (NULL);
        }
        maxvfsconf = buflen / sizeof(struct xvfsconf);

        if ((listptr = malloc(sizeof(char*) * maxvfsconf)) == NULL) {
                xo_warnx("malloc failed");
                free(keep_xvfsp);
                return (NULL);
        }

        for (cnt = 0, i = 0; i < maxvfsconf; i++) {
                if (xvfsp->vfc_flags & VFCF_NETWORK) {
                        listptr[cnt++] = strdup(xvfsp->vfc_name);
                        if (listptr[cnt-1] == NULL) {
                                xo_warnx("malloc failed");
                                free(listptr);
                                free(keep_xvfsp);
                                return (NULL);
                        }
                }
                xvfsp++;
        }

        if (cnt == 0 ||
            (str = malloc(sizeof(char) * (32 * cnt + cnt + 2))) == NULL) {
                if (cnt > 0)
                        xo_warnx("malloc failed");
                free(listptr);
                free(keep_xvfsp);
                return (NULL);
        }

        *str = 'n'; *(str + 1) = 'o';
        for (i = 0, strptr = str + 2; i < cnt; i++, strptr++) {
                strlcpy(strptr, listptr[i], 32);
                strptr += strlen(listptr[i]);
                *strptr = ',';
                free(listptr[i]);
        }
        *(--strptr) = '\0';

        free(keep_xvfsp);
        free(listptr);
        return (str);
}