/*      $OpenBSD: nfs.c,v 1.15 2017/05/08 20:13:46 patrick Exp $        */
/*      $NetBSD: nfs.c,v 1.19 1996/10/13 02:29:04 christos Exp $        */

/*-
 *  Copyright (c) 1993 John Brezak
 *  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.
 *  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. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `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 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/time.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <netinet/in.h>

#include "rpcv2.h"
#include "nfsv2.h"

#include "stand.h"
#include "saerrno.h"
#include "net.h"
#include "netif.h"
#include "nfs.h"
#include "rpc.h"

/* Define our own NFS attributes without NQNFS stuff. */
struct nfsv2_fattrs {
        u_int32_t       fa_type;
        u_int32_t       fa_mode;
        u_int32_t       fa_nlink;
        u_int32_t       fa_uid;
        u_int32_t       fa_gid;
        u_int32_t       fa_size;
        u_int32_t       fa_blocksize;
        u_int32_t       fa_rdev;
        u_int32_t       fa_blocks;
        u_int32_t       fa_fsid;
        u_int32_t       fa_fileid;
        struct nfsv2_time fa_atime;
        struct nfsv2_time fa_mtime;
        struct nfsv2_time fa_ctime;
};


struct nfs_read_args {
        u_char  fh[NFS_FHSIZE];
        u_int32_t       off;
        u_int32_t       len;
        u_int32_t       xxx;                    /* XXX what's this for? */
};

/* Data part of nfs rpc reply (also the largest thing we receive) */
#define NFSREAD_SIZE 1024
struct nfs_read_repl {
        u_int32_t       errno;
        struct  nfsv2_fattrs fa;
        u_int32_t       count;
        u_char  data[NFSREAD_SIZE];
};

struct nfs_readlnk_repl {
        u_int32_t       errno;
        u_int32_t       len;
        char    path[NFS_MAXPATHLEN];
};

struct nfs_iodesc {
        struct  iodesc  *iodesc;
        off_t   off;
        u_char  fh[NFS_FHSIZE];
        struct nfsv2_fattrs fa; /* all in network order */
};

struct nfs_iodesc nfs_root_node;


/*
 * Fetch the root file handle (call mount daemon)
 * On error, return non-zero and set errno.
 */
static int
nfs_getrootfh(struct iodesc *d, const char *path, u_char *fhp)
{
        int len;
        struct args {
                u_int32_t       len;
                char    path[FNAME_SIZE];
        } *args;
        struct repl {
                u_int32_t       errno;
                u_char  fh[NFS_FHSIZE];
        } *repl;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct args d;
        } sdata;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct repl d;
        } rdata;
        ssize_t cc;

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_getrootfh: %s\n", path);
#endif

        args = &sdata.d;
        repl = &rdata.d;

        bzero(args, sizeof(*args));
        len = strlen(path);
        if (len > sizeof(args->path))
                len = sizeof(args->path);
        args->len = htonl(len);
        bcopy(path, args->path, len);
        len = 4 + roundup(len, 4);

        cc = rpc_call(d, RPCPROG_MNT, RPCMNT_VER1, RPCMNT_MOUNT,
            args, len, repl, sizeof(*repl));
        if (cc == -1) {
                /* errno was set by rpc_call */
                return (-1);
        }
        if (cc < 4) {
                errno = EBADRPC;
                return (-1);
        }
        if (repl->errno) {
                errno = ntohl(repl->errno);
                return (-1);
        }
        bcopy(repl->fh, fhp, sizeof(repl->fh));
        return (0);
}

/*
 * Lookup a file.  Store handle and attributes.
 * Return zero or error number.
 */
static int
nfs_lookupfh(struct nfs_iodesc *d, char *name, struct nfs_iodesc *newfd)
{
        int len, rlen;
        struct args {
                u_char  fh[NFS_FHSIZE];
                u_int32_t       len;
                char    name[FNAME_SIZE];
        } *args;
        struct repl {
                u_int32_t       errno;
                u_char  fh[NFS_FHSIZE];
                struct  nfsv2_fattrs fa;
        } *repl;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct args d;
        } sdata;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct repl d;
        } rdata;
        ssize_t cc;

#ifdef NFS_DEBUG
        if (debug)
                printf("lookupfh: called\n");
#endif

        args = &sdata.d;
        repl = &rdata.d;

        bzero(args, sizeof(*args));
        bcopy(d->fh, args->fh, sizeof(args->fh));
        len = strlen(name);
        if (len > sizeof(args->name))
                len = sizeof(args->name);
        bcopy(name, args->name, len);
        args->len = htonl(len);
        len = 4 + roundup(len, 4);
        len += NFS_FHSIZE;

        rlen = sizeof(*repl);

        cc = rpc_call(d->iodesc, NFS_PROG, NFS_VER2, NFSPROC_LOOKUP,
            args, len, repl, rlen);
        if (cc == -1)
                return (errno);         /* XXX - from rpc_call */
        if (cc < 4)
                return (EIO);
        if (repl->errno) {
                /* saerrno.h now matches NFS error numbers. */
                return (ntohl(repl->errno));
        }
        bcopy( repl->fh, &newfd->fh, sizeof(newfd->fh));
        bcopy(&repl->fa, &newfd->fa, sizeof(newfd->fa));
        return (0);
}

/*
 * Get the destination of a symbolic link.
 */
static int
nfs_readlink(struct nfs_iodesc *d, char *buf)
{
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                u_char fh[NFS_FHSIZE];
        } sdata;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct nfs_readlnk_repl d;
        } rdata;
        ssize_t cc;

#ifdef NFS_DEBUG
        if (debug)
                printf("readlink: called\n");
#endif

        bcopy(d->fh, sdata.fh, NFS_FHSIZE);
        cc = rpc_call(d->iodesc, NFS_PROG, NFS_VER2, NFSPROC_READLINK,
            sdata.fh, NFS_FHSIZE,
            &rdata.d, sizeof(rdata.d));
        if (cc == -1)
                return (errno);

        if (cc < 4)
                return (EIO);

        if (rdata.d.errno)
                return (ntohl(rdata.d.errno));

        rdata.d.len = ntohl(rdata.d.len);
        if (rdata.d.len > NFS_MAXPATHLEN)
                return (ENAMETOOLONG);

        bcopy(rdata.d.path, buf, rdata.d.len);
        buf[rdata.d.len] = 0;
        return (0);
}

/*
 * Read data from a file.
 * Return transfer count or -1 (and set errno)
 */
static ssize_t
nfs_readdata(struct nfs_iodesc *d, off_t off, void *addr, size_t len)
{
        struct nfs_read_args *args;
        struct nfs_read_repl *repl;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct nfs_read_args d;
        } sdata;
        struct {
                u_int32_t       h[RPC_HEADER_WORDS];
                struct nfs_read_repl d;
        } rdata;
        ssize_t cc;
        long x;
        int hlen, rlen;

        args = &sdata.d;
        repl = &rdata.d;

        bcopy(d->fh, args->fh, NFS_FHSIZE);
        args->off = htonl((u_int32_t)off);
        if (len > NFSREAD_SIZE)
                len = NFSREAD_SIZE;
        args->len = htonl((u_int32_t)len);
        args->xxx = htonl((u_int32_t)0);
        hlen = sizeof(*repl) - NFSREAD_SIZE;

        cc = rpc_call(d->iodesc, NFS_PROG, NFS_VER2, NFSPROC_READ,
            args, sizeof(*args),
            repl, sizeof(*repl));
        if (cc == -1) {
                /* errno was already set by rpc_call */
                return (-1);
        }
        if (cc < hlen) {
                errno = EBADRPC;
                return (-1);
        }
        if (repl->errno) {
                errno = ntohl(repl->errno);
                return (-1);
        }
        rlen = cc - hlen;
        x = ntohl(repl->count);
        if (rlen < x) {
                printf("nfsread: short packet, %d < %ld\n", rlen, x);
                errno = EBADRPC;
                return(-1);
        }
        bcopy(repl->data, addr, x);
        return (x);
}

/*
 * nfs_mount - mount this nfs filesystem to a host
 * On error, return non-zero and set errno.
 */
int
nfs_mount(int sock, struct in_addr ip, const char *path)
{
        struct iodesc *desc;
        struct nfsv2_fattrs *fa;

        if (!(desc = socktodesc(sock))) {
                errno = EINVAL;
                return(-1);
        }

        /* Bind to a reserved port. */
        desc->myport = htons(--rpc_port);
        desc->destip = ip;
        if (nfs_getrootfh(desc, path, nfs_root_node.fh))
                return (-1);
        nfs_root_node.iodesc = desc;
        /* Fake up attributes for the root dir. */
        fa = &nfs_root_node.fa;
        fa->fa_type  = htonl(NFDIR);
        fa->fa_mode  = htonl(0755);
        fa->fa_nlink = htonl(2);

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_mount: got fh for %s\n", path);
#endif

        return(0);
}

/*
 * Open a file.
 * return zero or error number
 */
int
nfs_open(char *path, struct open_file *f)
{
        struct nfs_iodesc *newfd, *currfd;
        char namebuf[NFS_MAXPATHLEN + 1], *cp, *ncp;
        char linkbuf[NFS_MAXPATHLEN + 1];
        int nlinks = 0, error = 0, c;

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_open: %s\n", path);
#endif
        if (nfs_root_node.iodesc == NULL) {
                printf("nfs_open: must mount first.\n");
                return (ENXIO);
        }

        currfd = &nfs_root_node;
        newfd = 0;

        cp = path;
        while (*cp) {
                /*
                 * Remove extra separators
                 */
                while (*cp == '/')
                        cp++;

                if (*cp == '\0')
                        break;
                /*
                 * Check that current node is a directory.
                 */
                if (currfd->fa.fa_type != htonl(NFDIR)) {
                        error = ENOTDIR;
                        goto out;
                }

                /* allocate file system specific data structure */
                newfd = alloc(sizeof(*newfd));
                newfd->iodesc = currfd->iodesc;
                newfd->off = 0;

                /*
                 * Get next component of path name.
                 */
                {
                        int len = 0;

                        ncp = cp;
                        while ((c = *cp) != '\0' && c != '/') {
                                if (++len > NFS_MAXNAMLEN) {
                                        error = ENOENT;
                                        goto out;
                                }
                                cp++;
                        }
                        *cp = '\0';
                }

                /* lookup a file handle */
                error = nfs_lookupfh(currfd, ncp, newfd);
                *cp = c;
                if (error)
                        goto out;

                /*
                 * Check for symbolic link
                 */
                if (newfd->fa.fa_type == htonl(NFLNK)) {
                        int link_len, len;

                        error = nfs_readlink(newfd, linkbuf);
                        if (error)
                                goto out;

                        link_len = strlen(linkbuf);
                        len = strlen(cp);

                        if (link_len + len > MAXPATHLEN ||
                            ++nlinks > MAXSYMLINKS) {
                                error = ENOENT;
                                goto out;
                        }

                        bcopy(cp, &namebuf[link_len], len + 1);
                        bcopy(linkbuf, namebuf, link_len);

                        /*
                         * If absolute pathname, restart at root.
                         * If relative pathname, restart at parent directory.
                         */
                        cp = namebuf;
                        if (*cp == '/') {
                                if (currfd != &nfs_root_node)
                                        free(currfd, sizeof(*currfd));
                                currfd = &nfs_root_node;
                        }

                        free(newfd, sizeof(*newfd));
                        newfd = 0;

                        continue;
                }

                if (currfd != &nfs_root_node)
                        free(currfd, sizeof(*currfd));
                currfd = newfd;
                newfd = 0;
        }

        error = 0;

out:
        if (!error) {
                f->f_fsdata = (void *)currfd;
                return (0);
        }

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_open: %s lookupfh failed: %s\n",
                    path, strerror(error));
#endif
        if (currfd != &nfs_root_node)
                free(currfd, sizeof(*currfd));
        if (newfd)
                free(newfd, sizeof(*newfd));

        return (error);
}

int
nfs_close(struct open_file *f)
{
        struct nfs_iodesc *fp = (struct nfs_iodesc *)f->f_fsdata;

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_close: fp=%p\n", fp);
#endif

        if (fp)
                free(fp, sizeof(struct nfs_iodesc));
        f->f_fsdata = NULL;

        return (0);
}

/*
 * read a portion of a file
 */
int
nfs_read(struct open_file *f, void *buf, size_t size, size_t *resid)
{
        struct nfs_iodesc *fp = (struct nfs_iodesc *)f->f_fsdata;
        ssize_t cc;
        char *addr = buf;

#ifdef NFS_DEBUG
        if (debug)
                printf("nfs_read: size=%d off=%d\n", size, (int)fp->off);
#endif
        while ((int)size > 0) {
                twiddle();
                cc = nfs_readdata(fp, fp->off, (void *)addr, size);
                /* XXX maybe should retry on certain errors */
                if (cc == -1) {
#ifdef NFS_DEBUG
                        if (debug)
                                printf("nfs_read: read: %s", strerror(errno));
#endif
                        return (errno); /* XXX - from nfs_readdata */
                }
                if (cc == 0) {
#ifdef NFS_DEBUG
                        if (debug)
                                printf("nfs_read: hit EOF unexpectantly");
#endif
                        goto ret;
                }
                fp->off += cc;
                addr += cc;
                size -= cc;
        }
ret:
        if (resid)
                *resid = size;

        return (0);
}

/*
 * Not implemented.
 */
int
nfs_write(struct open_file *f, void *buf, size_t size, size_t *resid)
{
        return (EROFS);
}

off_t
nfs_seek(struct open_file *f, off_t offset, int where)
{
        struct nfs_iodesc *d = (struct nfs_iodesc *)f->f_fsdata;
        u_int32_t size = ntohl(d->fa.fa_size);

        switch (where) {
        case SEEK_SET:
                d->off = offset;
                break;
        case SEEK_CUR:
                d->off += offset;
                break;
        case SEEK_END:
                d->off = size - offset;
                break;
        default:
                return (-1);
        }

        return (d->off);
}

/* NFNON=0, NFREG=1, NFDIR=2, NFBLK=3, NFCHR=4, NFLNK=5 */
const int nfs_stat_types[8] = {
        0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK, 0
};

int
nfs_stat(struct open_file *f, struct stat *sb)
{
        struct nfs_iodesc *fp = (struct nfs_iodesc *)f->f_fsdata;
        u_int32_t ftype, mode;

        ftype = ntohl(fp->fa.fa_type);
        mode  = ntohl(fp->fa.fa_mode);
        mode |= nfs_stat_types[ftype & 7];

        sb->st_mode  = mode;
        sb->st_nlink = ntohl(fp->fa.fa_nlink);
        sb->st_uid   = ntohl(fp->fa.fa_uid);
        sb->st_gid   = ntohl(fp->fa.fa_gid);
        sb->st_size  = ntohl(fp->fa.fa_size);

        return (0);
}

/*
 * Not implemented.
 */
#ifndef NO_READDIR
int
nfs_readdir(struct open_file *f, char *name)
{
        return (EROFS);
}
#endif