/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008 Dag-Erling Smørgrav
 * Copyright (c) 2008 Marshall Kirk McKusick
 * All rights reserved.
 *
 * 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
 *    in this position and unchanged.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/types.h>
#include <sys/endian.h>
#include <sys/mount.h>
#include <sys/stat.h>

#include <ufs/ufs/quota.h>

#include <errno.h>
#include <fcntl.h>
#include <fstab.h>
#include <grp.h>
#include <pwd.h>
#include <libutil.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

struct quotafile {
        int fd;                         /* -1 means using quotactl for access */
        int accmode;                    /* access mode */
        int wordsize;                   /* 32-bit or 64-bit limits */
        int quotatype;                  /* USRQUOTA or GRPQUOTA */
        dev_t dev;                      /* device */
        char fsname[MAXPATHLEN + 1];    /* mount point of filesystem */
        char qfname[MAXPATHLEN + 1];    /* quota file if not using quotactl */
};

static const char *qfextension[] = INITQFNAMES;

/*
 * Check to see if a particular quota is to be enabled.
 */
static int
hasquota(struct fstab *fs, int type, char *qfnamep, int qfbufsize)
{
        char *opt;
        char *cp;
        struct statfs sfb;
        char buf[BUFSIZ];
        static char initname, usrname[100], grpname[100];

        /*
         * 1) we only need one of these
         * 2) fstab may specify a different filename
         */
        if (!initname) {
                (void)snprintf(usrname, sizeof(usrname), "%s%s",
                    qfextension[USRQUOTA], QUOTAFILENAME);
                (void)snprintf(grpname, sizeof(grpname), "%s%s",
                    qfextension[GRPQUOTA], QUOTAFILENAME);
                initname = 1;
        }
        strcpy(buf, fs->fs_mntops);
        for (opt = strtok(buf, ","); opt; opt = strtok(NULL, ",")) {
                if ((cp = strchr(opt, '=')))
                        *cp++ = '\0';
                if (type == USRQUOTA && strcmp(opt, usrname) == 0)
                        break;
                if (type == GRPQUOTA && strcmp(opt, grpname) == 0)
                        break;
        }
        if (!opt)
                return (0);
        /*
         * Ensure that the filesystem is mounted.
         */
        if (statfs(fs->fs_file, &sfb) != 0 ||
            strcmp(fs->fs_file, sfb.f_mntonname)) {
                return (0);
        }
        if (cp) {
                strlcpy(qfnamep, cp, qfbufsize);
        } else {
                (void)snprintf(qfnamep, qfbufsize, "%s/%s.%s", fs->fs_file,
                    QUOTAFILENAME, qfextension[type]);
        }
        return (1);
}

struct quotafile *
quota_open(struct fstab *fs, int quotatype, int openflags)
{
        struct quotafile *qf;
        struct dqhdr64 dqh;
        struct group *grp;
        struct stat st;
        int qcmd, serrno = 0;
        int ufs;

        if ((qf = calloc(1, sizeof(*qf))) == NULL)
                return (NULL);
        qf->fd = -1;
        qf->quotatype = quotatype;
        strlcpy(qf->fsname, fs->fs_file, sizeof(qf->fsname));
        if (stat(qf->fsname, &st) != 0)
                goto error;
        qf->dev = st.st_dev;
        qcmd = QCMD(Q_GETQUOTASIZE, quotatype);
        ufs = strcmp(fs->fs_vfstype, "ufs") == 0;
        /*
         * On UFS, hasquota() fills in qf->qfname. But we only care about
         * this for UFS.  So we need to call hasquota() for UFS, first.
         */
        if (ufs) {
                serrno = hasquota(fs, quotatype, qf->qfname,
                    sizeof(qf->qfname));
        }
        if (quotactl(qf->fsname, qcmd, 0, &qf->wordsize) == 0)
                return (qf);
        if (!ufs) {
                errno = 0;
                goto error;
        } else if (serrno == 0) {
                errno = EOPNOTSUPP;
                goto error;
        }
        qf->accmode = openflags & O_ACCMODE;
        if ((qf->fd = open(qf->qfname, qf->accmode|O_CLOEXEC)) < 0 &&
            (openflags & O_CREAT) != O_CREAT)
                goto error;
        /* File open worked, so process it */
        if (qf->fd != -1) {
                qf->wordsize = 32;
                switch (read(qf->fd, &dqh, sizeof(dqh))) {
                case -1:
                        goto error;
                case sizeof(dqh):
                        if (strcmp(dqh.dqh_magic, Q_DQHDR64_MAGIC) != 0) {
                                /* no magic, assume 32 bits */
                                qf->wordsize = 32;
                                return (qf);
                        }
                        if (be32toh(dqh.dqh_version) != Q_DQHDR64_VERSION ||
                            be32toh(dqh.dqh_hdrlen) != sizeof(struct dqhdr64) ||
                            be32toh(dqh.dqh_reclen) != sizeof(struct dqblk64)) {
                                /* correct magic, wrong version / lengths */
                                errno = EINVAL;
                                goto error;
                        }
                        qf->wordsize = 64;
                        return (qf);
                default:
                        qf->wordsize = 32;
                        return (qf);
                }
                /* not reached */
        }
        /* open failed, but O_CREAT was specified, so create a new file */
        if ((qf->fd = open(qf->qfname, O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0)) <
            0)
                goto error;
        qf->wordsize = 64;
        memset(&dqh, 0, sizeof(dqh));
        memcpy(dqh.dqh_magic, Q_DQHDR64_MAGIC, sizeof(dqh.dqh_magic));
        dqh.dqh_version = htobe32(Q_DQHDR64_VERSION);
        dqh.dqh_hdrlen = htobe32(sizeof(struct dqhdr64));
        dqh.dqh_reclen = htobe32(sizeof(struct dqblk64));
        if (write(qf->fd, &dqh, sizeof(dqh)) != sizeof(dqh)) {
                /* it was one we created ourselves */
                unlink(qf->qfname);
                goto error;
        }
        grp = getgrnam(QUOTAGROUP);
        fchown(qf->fd, 0, grp ? grp->gr_gid : 0);
        fchmod(qf->fd, 0640);
        return (qf);
error:
        serrno = errno;
        /* did we have an open file? */
        if (qf->fd != -1)
                close(qf->fd);
        free(qf);
        errno = serrno;
        return (NULL);
}

void
quota_close(struct quotafile *qf)
{

        if (qf->fd != -1)
                close(qf->fd);
        free(qf);
}

int
quota_on(struct quotafile *qf)
{
        int qcmd;

        qcmd = QCMD(Q_QUOTAON, qf->quotatype);
        return (quotactl(qf->fsname, qcmd, 0, qf->qfname));
}

int
quota_off(struct quotafile *qf)
{

        return (quotactl(qf->fsname, QCMD(Q_QUOTAOFF, qf->quotatype), 0, 0));
}

const char *
quota_fsname(const struct quotafile *qf)
{

        return (qf->fsname);
}

const char *
quota_qfname(const struct quotafile *qf)
{

        return (qf->qfname);
}

int
quota_check_path(const struct quotafile *qf, const char *path)
{
        struct stat st;

        if (stat(path, &st) == -1)
                return (-1);
        return (st.st_dev == qf->dev);
}

int
quota_maxid(struct quotafile *qf)
{
        struct stat st;
        int maxid;

        if (stat(qf->qfname, &st) < 0)
                return (0);
        switch (qf->wordsize) {
        case 32:
                maxid = st.st_size / sizeof(struct dqblk32) - 1;
                break;
        case 64:
                maxid = st.st_size / sizeof(struct dqblk64) - 2;
                break;
        default:
                maxid = 0;
                break;
        }
        return (maxid > 0 ? maxid : 0);
}

static int
quota_read32(struct quotafile *qf, struct dqblk *dqb, int id)
{
        struct dqblk32 dqb32;
        off_t off;

        off = id * sizeof(struct dqblk32);
        if (lseek(qf->fd, off, SEEK_SET) == -1)
                return (-1);
        switch (read(qf->fd, &dqb32, sizeof(dqb32))) {
        case 0:
                memset(dqb, 0, sizeof(*dqb));
                return (0);
        case sizeof(dqb32):
                dqb->dqb_bhardlimit = dqb32.dqb_bhardlimit;
                dqb->dqb_bsoftlimit = dqb32.dqb_bsoftlimit;
                dqb->dqb_curblocks = dqb32.dqb_curblocks;
                dqb->dqb_ihardlimit = dqb32.dqb_ihardlimit;
                dqb->dqb_isoftlimit = dqb32.dqb_isoftlimit;
                dqb->dqb_curinodes = dqb32.dqb_curinodes;
                dqb->dqb_btime = dqb32.dqb_btime;
                dqb->dqb_itime = dqb32.dqb_itime;
                return (0);
        default:
                return (-1);
        }
}

static int
quota_read64(struct quotafile *qf, struct dqblk *dqb, int id)
{
        struct dqblk64 dqb64;
        off_t off;

        off = sizeof(struct dqhdr64) + id * sizeof(struct dqblk64);
        if (lseek(qf->fd, off, SEEK_SET) == -1)
                return (-1);
        switch (read(qf->fd, &dqb64, sizeof(dqb64))) {
        case 0:
                memset(dqb, 0, sizeof(*dqb));
                return (0);
        case sizeof(dqb64):
                dqb->dqb_bhardlimit = be64toh(dqb64.dqb_bhardlimit);
                dqb->dqb_bsoftlimit = be64toh(dqb64.dqb_bsoftlimit);
                dqb->dqb_curblocks = be64toh(dqb64.dqb_curblocks);
                dqb->dqb_ihardlimit = be64toh(dqb64.dqb_ihardlimit);
                dqb->dqb_isoftlimit = be64toh(dqb64.dqb_isoftlimit);
                dqb->dqb_curinodes = be64toh(dqb64.dqb_curinodes);
                dqb->dqb_btime = be64toh(dqb64.dqb_btime);
                dqb->dqb_itime = be64toh(dqb64.dqb_itime);
                return (0);
        default:
                return (-1);
        }
}

int
quota_read(struct quotafile *qf, struct dqblk *dqb, int id)
{
        int qcmd;

        if (qf->fd == -1) {
                qcmd = QCMD(Q_GETQUOTA, qf->quotatype);
                return (quotactl(qf->fsname, qcmd, id, dqb));
        }
        switch (qf->wordsize) {
        case 32:
                return (quota_read32(qf, dqb, id));
        case 64:
                return (quota_read64(qf, dqb, id));
        default:
                errno = EINVAL;
                return (-1);
        }
        /* not reached */
}

#define CLIP32(u64) ((u64) > UINT32_MAX ? UINT32_MAX : (uint32_t)(u64))

static int
quota_write32(struct quotafile *qf, const struct dqblk *dqb, int id)
{
        struct dqblk32 dqb32;
        off_t off;

        dqb32.dqb_bhardlimit = CLIP32(dqb->dqb_bhardlimit);
        dqb32.dqb_bsoftlimit = CLIP32(dqb->dqb_bsoftlimit);
        dqb32.dqb_curblocks = CLIP32(dqb->dqb_curblocks);
        dqb32.dqb_ihardlimit = CLIP32(dqb->dqb_ihardlimit);
        dqb32.dqb_isoftlimit = CLIP32(dqb->dqb_isoftlimit);
        dqb32.dqb_curinodes = CLIP32(dqb->dqb_curinodes);
        dqb32.dqb_btime = CLIP32(dqb->dqb_btime);
        dqb32.dqb_itime = CLIP32(dqb->dqb_itime);

        off = id * sizeof(struct dqblk32);
        if (lseek(qf->fd, off, SEEK_SET) == -1)
                return (-1);
        if (write(qf->fd, &dqb32, sizeof(dqb32)) == sizeof(dqb32))
                return (0);
        return (-1);
}

static int
quota_write64(struct quotafile *qf, const struct dqblk *dqb, int id)
{
        struct dqblk64 dqb64;
        off_t off;

        dqb64.dqb_bhardlimit = htobe64(dqb->dqb_bhardlimit);
        dqb64.dqb_bsoftlimit = htobe64(dqb->dqb_bsoftlimit);
        dqb64.dqb_curblocks = htobe64(dqb->dqb_curblocks);
        dqb64.dqb_ihardlimit = htobe64(dqb->dqb_ihardlimit);
        dqb64.dqb_isoftlimit = htobe64(dqb->dqb_isoftlimit);
        dqb64.dqb_curinodes = htobe64(dqb->dqb_curinodes);
        dqb64.dqb_btime = htobe64(dqb->dqb_btime);
        dqb64.dqb_itime = htobe64(dqb->dqb_itime);

        off = sizeof(struct dqhdr64) + id * sizeof(struct dqblk64);
        if (lseek(qf->fd, off, SEEK_SET) == -1)
                return (-1);
        if (write(qf->fd, &dqb64, sizeof(dqb64)) == sizeof(dqb64))
                return (0);
        return (-1);
}

int
quota_write_usage(struct quotafile *qf, struct dqblk *dqb, int id)
{
        struct dqblk dqbuf;
        int qcmd;

        if (qf->fd == -1) {
                qcmd = QCMD(Q_SETUSE, qf->quotatype);
                return (quotactl(qf->fsname, qcmd, id, dqb));
        }
        /*
         * Have to do read-modify-write of quota in file.
         */
        if ((qf->accmode & O_RDWR) != O_RDWR) {
                errno = EBADF;
                return (-1);
        }
        if (quota_read(qf, &dqbuf, id) != 0)
                return (-1);
        /*
         * Reset time limit if have a soft limit and were
         * previously under it, but are now over it.
         */
        if (dqbuf.dqb_bsoftlimit && id != 0 &&
            dqbuf.dqb_curblocks < dqbuf.dqb_bsoftlimit &&
            dqb->dqb_curblocks >= dqbuf.dqb_bsoftlimit)
                dqbuf.dqb_btime = 0;
        if (dqbuf.dqb_isoftlimit && id != 0 &&
            dqbuf.dqb_curinodes < dqbuf.dqb_isoftlimit &&
            dqb->dqb_curinodes >= dqbuf.dqb_isoftlimit)
                dqbuf.dqb_itime = 0;
        dqbuf.dqb_curinodes = dqb->dqb_curinodes;
        dqbuf.dqb_curblocks = dqb->dqb_curblocks;
        /*
         * Write it back.
         */
        switch (qf->wordsize) {
        case 32:
                return (quota_write32(qf, &dqbuf, id));
        case 64:
                return (quota_write64(qf, &dqbuf, id));
        default:
                errno = EINVAL;
                return (-1);
        }
        /* not reached */
}

int
quota_write_limits(struct quotafile *qf, struct dqblk *dqb, int id)
{
        struct dqblk dqbuf;
        int qcmd;

        if (qf->fd == -1) {
                qcmd = QCMD(Q_SETQUOTA, qf->quotatype);
                return (quotactl(qf->fsname, qcmd, id, dqb));
        }
        /*
         * Have to do read-modify-write of quota in file.
         */
        if ((qf->accmode & O_RDWR) != O_RDWR) {
                errno = EBADF;
                return (-1);
        }
        if (quota_read(qf, &dqbuf, id) != 0)
                return (-1);
        /*
         * Reset time limit if have a soft limit and were
         * previously under it, but are now over it
         * or if there previously was no soft limit, but
         * now have one and are over it.
         */
        if (dqbuf.dqb_bsoftlimit && id != 0 &&
            dqbuf.dqb_curblocks < dqbuf.dqb_bsoftlimit &&
            dqbuf.dqb_curblocks >= dqb->dqb_bsoftlimit)
                dqb->dqb_btime = 0;
        if (dqbuf.dqb_bsoftlimit == 0 && id != 0 &&
            dqb->dqb_bsoftlimit > 0 &&
            dqbuf.dqb_curblocks >= dqb->dqb_bsoftlimit)
                dqb->dqb_btime = 0;
        if (dqbuf.dqb_isoftlimit && id != 0 &&
            dqbuf.dqb_curinodes < dqbuf.dqb_isoftlimit &&
            dqbuf.dqb_curinodes >= dqb->dqb_isoftlimit)
                dqb->dqb_itime = 0;
        if (dqbuf.dqb_isoftlimit == 0 && id !=0 &&
            dqb->dqb_isoftlimit > 0 &&
            dqbuf.dqb_curinodes >= dqb->dqb_isoftlimit)
                dqb->dqb_itime = 0;
        dqb->dqb_curinodes = dqbuf.dqb_curinodes;
        dqb->dqb_curblocks = dqbuf.dqb_curblocks;
        /*
         * Write it back.
         */
        switch (qf->wordsize) {
        case 32:
                return (quota_write32(qf, dqb, id));
        case 64:
                return (quota_write64(qf, dqb, id));
        default:
                errno = EINVAL;
                return (-1);
        }
        /* not reached */
}

/*
 * Convert a quota file from one format to another.
 */
int
quota_convert(struct quotafile *qf, int wordsize)
{
        struct quotafile *newqf;
        struct dqhdr64 dqh;
        struct dqblk dqblk;
        struct group *grp;
        int serrno, maxid, id, fd;

        /*
         * Quotas must not be active and quotafile must be open
         * for reading and writing.
         */
        if ((qf->accmode & O_RDWR) != O_RDWR || qf->fd == -1) {
                errno = EBADF;
                return (-1);
        }
        if ((wordsize != 32 && wordsize != 64) ||
             wordsize == qf->wordsize) {
                errno = EINVAL;
                return (-1);
        }
        maxid = quota_maxid(qf);
        if ((newqf = calloc(1, sizeof(*qf))) == NULL) {
                errno = ENOMEM;
                return (-1);
        }
        *newqf = *qf;
        snprintf(newqf->qfname, MAXPATHLEN + 1, "%s_%d.orig", qf->qfname,
            qf->wordsize);
        if (rename(qf->qfname, newqf->qfname) < 0) {
                free(newqf);
                return (-1);
        }
        if ((newqf->fd = open(qf->qfname, O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC,
            0)) < 0) {
                serrno = errno;
                goto error;
        }
        newqf->wordsize = wordsize;
        if (wordsize == 64) {
                memset(&dqh, 0, sizeof(dqh));
                memcpy(dqh.dqh_magic, Q_DQHDR64_MAGIC, sizeof(dqh.dqh_magic));
                dqh.dqh_version = htobe32(Q_DQHDR64_VERSION);
                dqh.dqh_hdrlen = htobe32(sizeof(struct dqhdr64));
                dqh.dqh_reclen = htobe32(sizeof(struct dqblk64));
                if (write(newqf->fd, &dqh, sizeof(dqh)) != sizeof(dqh)) {
                        serrno = errno;
                        goto error;
                }
        }
        grp = getgrnam(QUOTAGROUP);
        fchown(newqf->fd, 0, grp ? grp->gr_gid : 0);
        fchmod(newqf->fd, 0640);
        for (id = 0; id <= maxid; id++) {
                if ((quota_read(qf, &dqblk, id)) < 0)
                        break;
                switch (newqf->wordsize) {
                case 32:
                        if ((quota_write32(newqf, &dqblk, id)) < 0)
                                break;
                        continue;
                case 64:
                        if ((quota_write64(newqf, &dqblk, id)) < 0)
                                break;
                        continue;
                default:
                        errno = EINVAL;
                        break;
                }
        }
        if (id < maxid) {
                serrno = errno;
                goto error;
        }
        /*
         * Update the passed in quotafile to reference the new file
         * of the converted format size.
         */
        fd = qf->fd;
        qf->fd = newqf->fd;
        newqf->fd = fd;
        qf->wordsize = newqf->wordsize;
        quota_close(newqf);
        return (0);
error:
        /* put back the original file */
        (void) rename(newqf->qfname, qf->qfname);
        quota_close(newqf);
        errno = serrno;
        return (-1);
}