// SPDX-License-Identifier: GPL-2.0-only
/*
 * 9P Protocol Support Code
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *
 *  Base on code from Anthony Liguori <aliguori@us.ibm.com>
 *  Copyright (C) 2008 by IBM, Corp.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/uio.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "protocol.h"

#include <trace/events/9p.h>

/* len[2] text[len] */
#define P9_STRLEN(s) \
        (2 + min_t(size_t, s ? strlen(s) : 0, USHRT_MAX))

/**
 * p9_msg_buf_size - Returns a buffer size sufficiently large to hold the
 * intended 9p message.
 * @c: client
 * @type: message type
 * @fmt: format template for assembling request message
 * (see p9pdu_vwritef)
 * @ap: variable arguments to be fed to passed format template
 * (see p9pdu_vwritef)
 *
 * Note: Even for response types (P9_R*) the format template and variable
 * arguments must always be for the originating request type (P9_T*).
 */
size_t p9_msg_buf_size(struct p9_client *c, enum p9_msg_t type,
                        const char *fmt, va_list ap)
{
        /* size[4] type[1] tag[2] */
        const int hdr = 4 + 1 + 2;
        /* ename[s] errno[4] */
        const int rerror_size = hdr + P9_ERRMAX + 4;
        /* ecode[4] */
        const int rlerror_size = hdr + 4;
        const int err_size =
                c->proto_version == p9_proto_2000L ? rlerror_size : rerror_size;

        static_assert(NAME_MAX <= 4*1024, "p9_msg_buf_size() currently assumes "
                                  "a max. allowed directory entry name length of 4k");

        switch (type) {

        /* message types not used at all */
        case P9_TERROR:
        case P9_TLERROR:
        case P9_TAUTH:
        case P9_RAUTH:
                BUG();

        /* variable length & potentially large message types */
        case P9_TATTACH:
                BUG_ON(strcmp("ddss?u", fmt));
                va_arg(ap, int32_t);
                va_arg(ap, int32_t);
                {
                        const char *uname = va_arg(ap, const char *);
                        const char *aname = va_arg(ap, const char *);
                        /* fid[4] afid[4] uname[s] aname[s] n_uname[4] */
                        return hdr + 4 + 4 + P9_STRLEN(uname) + P9_STRLEN(aname) + 4;
                }
        case P9_TWALK:
                BUG_ON(strcmp("ddT", fmt));
                va_arg(ap, int32_t);
                va_arg(ap, int32_t);
                {
                        uint i, nwname = va_arg(ap, int);
                        size_t wname_all;
                        const char **wnames = va_arg(ap, const char **);
                        for (i = 0, wname_all = 0; i < nwname; ++i) {
                                wname_all += P9_STRLEN(wnames[i]);
                        }
                        /* fid[4] newfid[4] nwname[2] nwname*(wname[s]) */
                        return hdr + 4 + 4 + 2 + wname_all;
                }
        case P9_RWALK:
                BUG_ON(strcmp("ddT", fmt));
                va_arg(ap, int32_t);
                va_arg(ap, int32_t);
                {
                        uint nwname = va_arg(ap, int);
                        /* nwqid[2] nwqid*(wqid[13]) */
                        return max_t(size_t, hdr + 2 + nwname * 13, err_size);
                }
        case P9_TCREATE:
                BUG_ON(strcmp("dsdb?s", fmt));
                va_arg(ap, int32_t);
                {
                        const char *name = va_arg(ap, const char *);
                        if (c->proto_version == p9_proto_legacy) {
                                /* fid[4] name[s] perm[4] mode[1] */
                                return hdr + 4 + P9_STRLEN(name) + 4 + 1;
                        } else {
                                va_arg(ap, int32_t);
                                va_arg(ap, int);
                                {
                                        const char *ext = va_arg(ap, const char *);
                                        /* fid[4] name[s] perm[4] mode[1] extension[s] */
                                        return hdr + 4 + P9_STRLEN(name) + 4 + 1 + P9_STRLEN(ext);
                                }
                        }
                }
        case P9_TLCREATE:
                BUG_ON(strcmp("dsddg", fmt));
                va_arg(ap, int32_t);
                {
                        const char *name = va_arg(ap, const char *);
                        /* fid[4] name[s] flags[4] mode[4] gid[4] */
                        return hdr + 4 + P9_STRLEN(name) + 4 + 4 + 4;
                }
        case P9_RREAD:
        case P9_RREADDIR:
                BUG_ON(strcmp("dqd", fmt));
                va_arg(ap, int32_t);
                va_arg(ap, int64_t);
                {
                        const int32_t count = va_arg(ap, int32_t);
                        /* count[4] data[count] */
                        return max_t(size_t, hdr + 4 + count, err_size);
                }
        case P9_TWRITE:
                BUG_ON(strcmp("dqV", fmt));
                va_arg(ap, int32_t);
                va_arg(ap, int64_t);
                {
                        const int32_t count = va_arg(ap, int32_t);
                        /* fid[4] offset[8] count[4] data[count] */
                        return hdr + 4 + 8 + 4 + count;
                }
        case P9_TRENAMEAT:
                BUG_ON(strcmp("dsds", fmt));
                va_arg(ap, int32_t);
                {
                        const char *oldname, *newname;
                        oldname = va_arg(ap, const char *);
                        va_arg(ap, int32_t);
                        newname = va_arg(ap, const char *);
                        /* olddirfid[4] oldname[s] newdirfid[4] newname[s] */
                        return hdr + 4 + P9_STRLEN(oldname) + 4 + P9_STRLEN(newname);
                }
        case P9_TSYMLINK:
                BUG_ON(strcmp("dssg", fmt));
                va_arg(ap, int32_t);
                {
                        const char *name = va_arg(ap, const char *);
                        const char *symtgt = va_arg(ap, const char *);
                        /* fid[4] name[s] symtgt[s] gid[4] */
                        return hdr + 4 + P9_STRLEN(name) + P9_STRLEN(symtgt) + 4;
                }

        case P9_RERROR:
                return rerror_size;
        case P9_RLERROR:
                return rlerror_size;

        /* small message types */
        case P9_TWSTAT:
        case P9_RSTAT:
        case P9_RREADLINK:
        case P9_TXATTRWALK:
        case P9_TXATTRCREATE:
        case P9_TLINK:
        case P9_TMKDIR:
        case P9_TMKNOD:
        case P9_TRENAME:
        case P9_TUNLINKAT:
        case P9_TLOCK:
                return 8 * 1024;

        /* tiny message types */
        default:
                return 4 * 1024;

        }
}

static int
p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);

void p9stat_free(struct p9_wstat *stbuf)
{
        kfree(stbuf->name);
        stbuf->name = NULL;
        kfree(stbuf->uid);
        stbuf->uid = NULL;
        kfree(stbuf->gid);
        stbuf->gid = NULL;
        kfree(stbuf->muid);
        stbuf->muid = NULL;
        kfree(stbuf->extension);
        stbuf->extension = NULL;
}
EXPORT_SYMBOL(p9stat_free);

size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
{
        size_t len = min(pdu->size - pdu->offset, size);

        memcpy(data, &pdu->sdata[pdu->offset], len);
        pdu->offset += len;
        return size - len;
}

static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
{
        size_t len = min(pdu->capacity - pdu->size, size);

        memcpy(&pdu->sdata[pdu->size], data, len);
        pdu->size += len;
        return size - len;
}

static size_t
pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
{
        size_t len = min(pdu->capacity - pdu->size, size);

        if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, from))
                len = 0;

        pdu->size += len;
        return size - len;
}

/*      b - int8_t
 *      w - int16_t
 *      d - int32_t
 *      q - int64_t
 *      s - string
 *      u - numeric uid
 *      g - numeric gid
 *      S - stat
 *      Q - qid
 *      D - data blob (int32_t size followed by void *, results are not freed)
 *      T - array of strings (int16_t count, followed by strings)
 *      R - array of qids (int16_t count, followed by qids)
 *      A - stat for 9p2000.L (p9_stat_dotl)
 *      ? - if optional = 1, continue parsing
 */

static int
p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
             va_list ap)
{
        const char *ptr;
        int errcode = 0;

        for (ptr = fmt; *ptr; ptr++) {
                switch (*ptr) {
                case 'b':{
                                int8_t *val = va_arg(ap, int8_t *);
                                if (pdu_read(pdu, val, sizeof(*val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                        }
                        break;
                case 'w':{
                                int16_t *val = va_arg(ap, int16_t *);
                                __le16 le_val;
                                if (pdu_read(pdu, &le_val, sizeof(le_val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                                *val = le16_to_cpu(le_val);
                        }
                        break;
                case 'd':{
                                int32_t *val = va_arg(ap, int32_t *);
                                __le32 le_val;
                                if (pdu_read(pdu, &le_val, sizeof(le_val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                                *val = le32_to_cpu(le_val);
                        }
                        break;
                case 'q':{
                                int64_t *val = va_arg(ap, int64_t *);
                                __le64 le_val;
                                if (pdu_read(pdu, &le_val, sizeof(le_val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                                *val = le64_to_cpu(le_val);
                        }
                        break;
                case 's':{
                                char **sptr = va_arg(ap, char **);
                                uint16_t len;

                                errcode = p9pdu_readf(pdu, proto_version,
                                                                "w", &len);
                                if (errcode)
                                        break;

                                *sptr = kmalloc(len + 1, GFP_NOFS);
                                if (*sptr == NULL) {
                                        errcode = -ENOMEM;
                                        break;
                                }
                                if (pdu_read(pdu, *sptr, len)) {
                                        errcode = -EFAULT;
                                        kfree(*sptr);
                                        *sptr = NULL;
                                } else
                                        (*sptr)[len] = 0;
                        }
                        break;
                case 'u': {
                                kuid_t *uid = va_arg(ap, kuid_t *);
                                __le32 le_val;
                                if (pdu_read(pdu, &le_val, sizeof(le_val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                                *uid = make_kuid(&init_user_ns,
                                                 le32_to_cpu(le_val));
                        } break;
                case 'g': {
                                kgid_t *gid = va_arg(ap, kgid_t *);
                                __le32 le_val;
                                if (pdu_read(pdu, &le_val, sizeof(le_val))) {
                                        errcode = -EFAULT;
                                        break;
                                }
                                *gid = make_kgid(&init_user_ns,
                                                 le32_to_cpu(le_val));
                        } break;
                case 'Q':{
                                struct p9_qid *qid =
                                    va_arg(ap, struct p9_qid *);

                                errcode = p9pdu_readf(pdu, proto_version, "bdq",
                                                      &qid->type, &qid->version,
                                                      &qid->path);
                        }
                        break;
                case 'S':{
                                struct p9_wstat *stbuf =
                                    va_arg(ap, struct p9_wstat *);

                                memset(stbuf, 0, sizeof(struct p9_wstat));
                                stbuf->n_uid = stbuf->n_muid = INVALID_UID;
                                stbuf->n_gid = INVALID_GID;

                                errcode =
                                    p9pdu_readf(pdu, proto_version,
                                                "wwdQdddqssss?sugu",
                                                &stbuf->size, &stbuf->type,
                                                &stbuf->dev, &stbuf->qid,
                                                &stbuf->mode, &stbuf->atime,
                                                &stbuf->mtime, &stbuf->length,
                                                &stbuf->name, &stbuf->uid,
                                                &stbuf->gid, &stbuf->muid,
                                                &stbuf->extension,
                                                &stbuf->n_uid, &stbuf->n_gid,
                                                &stbuf->n_muid);
                                if (errcode)
                                        p9stat_free(stbuf);
                        }
                        break;
                case 'D':{
                                uint32_t *count = va_arg(ap, uint32_t *);
                                void **data = va_arg(ap, void **);

                                errcode =
                                    p9pdu_readf(pdu, proto_version, "d", count);
                                if (!errcode) {
                                        *count =
                                            min_t(uint32_t, *count,
                                                  pdu->size - pdu->offset);
                                        *data = &pdu->sdata[pdu->offset];
                                }
                        }
                        break;
                case 'T':{
                                uint16_t *nwname = va_arg(ap, uint16_t *);
                                char ***wnames = va_arg(ap, char ***);

                                *wnames = NULL;

                                errcode = p9pdu_readf(pdu, proto_version,
                                                                "w", nwname);
                                if (!errcode) {
                                        *wnames =
                                            kmalloc_array(*nwname,
                                                          sizeof(char *),
                                                          GFP_NOFS);
                                        if (!*wnames)
                                                errcode = -ENOMEM;
                                        else
                                                (*wnames)[0] = NULL;
                                }

                                if (!errcode) {
                                        int i;

                                        for (i = 0; i < *nwname; i++) {
                                                errcode =
                                                    p9pdu_readf(pdu,
                                                                proto_version,
                                                                "s",
                                                                &(*wnames)[i]);
                                                if (errcode) {
                                                        (*wnames)[i] = NULL;
                                                        break;
                                                }
                                        }
                                }

                                if (errcode) {
                                        if (*wnames) {
                                                int i;

                                                for (i = 0; i < *nwname; i++) {
                                                        if (!(*wnames)[i])
                                                                break;
                                                        kfree((*wnames)[i]);
                                                }
                                                kfree(*wnames);
                                                *wnames = NULL;
                                        }
                                }
                        }
                        break;
                case 'R':{
                                uint16_t *nwqid = va_arg(ap, uint16_t *);
                                struct p9_qid **wqids =
                                    va_arg(ap, struct p9_qid **);

                                *wqids = NULL;

                                errcode =
                                    p9pdu_readf(pdu, proto_version, "w", nwqid);
                                if (!errcode) {
                                        *wqids =
                                            kmalloc_objs(struct p9_qid, *nwqid,
                                                         GFP_NOFS);
                                        if (*wqids == NULL)
                                                errcode = -ENOMEM;
                                }

                                if (!errcode) {
                                        int i;

                                        for (i = 0; i < *nwqid; i++) {
                                                errcode =
                                                    p9pdu_readf(pdu,
                                                                proto_version,
                                                                "Q",
                                                                &(*wqids)[i]);
                                                if (errcode)
                                                        break;
                                        }
                                }

                                if (errcode) {
                                        kfree(*wqids);
                                        *wqids = NULL;
                                }
                        }
                        break;
                case 'A': {
                                struct p9_stat_dotl *stbuf =
                                    va_arg(ap, struct p9_stat_dotl *);

                                memset(stbuf, 0, sizeof(struct p9_stat_dotl));
                                errcode =
                                    p9pdu_readf(pdu, proto_version,
                                        "qQdugqqqqqqqqqqqqqqq",
                                        &stbuf->st_result_mask,
                                        &stbuf->qid,
                                        &stbuf->st_mode,
                                        &stbuf->st_uid, &stbuf->st_gid,
                                        &stbuf->st_nlink,
                                        &stbuf->st_rdev, &stbuf->st_size,
                                        &stbuf->st_blksize, &stbuf->st_blocks,
                                        &stbuf->st_atime_sec,
                                        &stbuf->st_atime_nsec,
                                        &stbuf->st_mtime_sec,
                                        &stbuf->st_mtime_nsec,
                                        &stbuf->st_ctime_sec,
                                        &stbuf->st_ctime_nsec,
                                        &stbuf->st_btime_sec,
                                        &stbuf->st_btime_nsec,
                                        &stbuf->st_gen,
                                        &stbuf->st_data_version);
                        }
                        break;
                case '?':
                        if ((proto_version != p9_proto_2000u) &&
                                (proto_version != p9_proto_2000L))
                                return 0;
                        break;
                default:
                        BUG();
                        break;
                }

                if (errcode)
                        break;
        }

        return errcode;
}

int
p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
        va_list ap)
{
        const char *ptr;
        int errcode = 0;

        for (ptr = fmt; *ptr; ptr++) {
                switch (*ptr) {
                case 'b':{
                                int8_t val = va_arg(ap, int);
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        }
                        break;
                case 'w':{
                                __le16 val = cpu_to_le16(va_arg(ap, int));
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        }
                        break;
                case 'd':{
                                __le32 val = cpu_to_le32(va_arg(ap, int32_t));
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        }
                        break;
                case 'q':{
                                __le64 val = cpu_to_le64(va_arg(ap, int64_t));
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        }
                        break;
                case 's':{
                                const char *sptr = va_arg(ap, const char *);
                                uint16_t len = 0;
                                if (sptr)
                                        len = min_t(size_t, strlen(sptr),
                                                                USHRT_MAX);

                                errcode = p9pdu_writef(pdu, proto_version,
                                                                "w", len);
                                if (!errcode && pdu_write(pdu, sptr, len))
                                        errcode = -EFAULT;
                        }
                        break;
                case 'u': {
                                kuid_t uid = va_arg(ap, kuid_t);
                                __le32 val = cpu_to_le32(
                                                from_kuid(&init_user_ns, uid));
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        } break;
                case 'g': {
                                kgid_t gid = va_arg(ap, kgid_t);
                                __le32 val = cpu_to_le32(
                                                from_kgid(&init_user_ns, gid));
                                if (pdu_write(pdu, &val, sizeof(val)))
                                        errcode = -EFAULT;
                        } break;
                case 'Q':{
                                const struct p9_qid *qid =
                                    va_arg(ap, const struct p9_qid *);
                                errcode =
                                    p9pdu_writef(pdu, proto_version, "bdq",
                                                 qid->type, qid->version,
                                                 qid->path);
                        } break;
                case 'S':{
                                const struct p9_wstat *stbuf =
                                    va_arg(ap, const struct p9_wstat *);
                                errcode =
                                    p9pdu_writef(pdu, proto_version,
                                                 "wwdQdddqssss?sugu",
                                                 stbuf->size, stbuf->type,
                                                 stbuf->dev, &stbuf->qid,
                                                 stbuf->mode, stbuf->atime,
                                                 stbuf->mtime, stbuf->length,
                                                 stbuf->name, stbuf->uid,
                                                 stbuf->gid, stbuf->muid,
                                                 stbuf->extension, stbuf->n_uid,
                                                 stbuf->n_gid, stbuf->n_muid);
                        } break;
                case 'V':{
                                uint32_t count = va_arg(ap, uint32_t);
                                struct iov_iter *from =
                                                va_arg(ap, struct iov_iter *);
                                errcode = p9pdu_writef(pdu, proto_version, "d",
                                                                        count);
                                if (!errcode && pdu_write_u(pdu, from, count))
                                        errcode = -EFAULT;
                        }
                        break;
                case 'T':{
                                uint16_t nwname = va_arg(ap, int);
                                const char **wnames = va_arg(ap, const char **);

                                errcode = p9pdu_writef(pdu, proto_version, "w",
                                                                        nwname);
                                if (!errcode) {
                                        int i;

                                        for (i = 0; i < nwname; i++) {
                                                errcode =
                                                    p9pdu_writef(pdu,
                                                                proto_version,
                                                                 "s",
                                                                 wnames[i]);
                                                if (errcode)
                                                        break;
                                        }
                                }
                        }
                        break;
                case 'R':{
                                uint16_t nwqid = va_arg(ap, int);
                                struct p9_qid *wqids =
                                    va_arg(ap, struct p9_qid *);

                                errcode = p9pdu_writef(pdu, proto_version, "w",
                                                                        nwqid);
                                if (!errcode) {
                                        int i;

                                        for (i = 0; i < nwqid; i++) {
                                                errcode =
                                                    p9pdu_writef(pdu,
                                                                proto_version,
                                                                 "Q",
                                                                 &wqids[i]);
                                                if (errcode)
                                                        break;
                                        }
                                }
                        }
                        break;
                case 'I':{
                                struct p9_iattr_dotl *p9attr = va_arg(ap,
                                                        struct p9_iattr_dotl *);

                                errcode = p9pdu_writef(pdu, proto_version,
                                                        "ddugqqqqq",
                                                        p9attr->valid,
                                                        p9attr->mode,
                                                        p9attr->uid,
                                                        p9attr->gid,
                                                        p9attr->size,
                                                        p9attr->atime_sec,
                                                        p9attr->atime_nsec,
                                                        p9attr->mtime_sec,
                                                        p9attr->mtime_nsec);
                        }
                        break;
                case '?':
                        if ((proto_version != p9_proto_2000u) &&
                                (proto_version != p9_proto_2000L))
                                return 0;
                        break;
                default:
                        BUG();
                        break;
                }

                if (errcode)
                        break;
        }

        return errcode;
}

int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
{
        va_list ap;
        int ret;

        va_start(ap, fmt);
        ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
        va_end(ap);

        return ret;
}

static int
p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
{
        va_list ap;
        int ret;

        va_start(ap, fmt);
        ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
        va_end(ap);

        return ret;
}

int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
{
        struct p9_fcall fake_pdu;
        int ret;

        fake_pdu.size = len;
        fake_pdu.capacity = len;
        fake_pdu.sdata = buf;
        fake_pdu.offset = 0;

        ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
        if (ret) {
                p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
                trace_9p_protocol_dump(clnt, &fake_pdu);
                return ret;
        }

        return fake_pdu.offset;
}
EXPORT_SYMBOL(p9stat_read);

int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
{
        pdu->id = type;
        return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
}

int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
{
        int size = pdu->size;
        int err;

        pdu->size = 0;
        err = p9pdu_writef(pdu, 0, "d", size);
        pdu->size = size;

        trace_9p_protocol_dump(clnt, pdu);
        p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
                 pdu->size, pdu->id, pdu->tag);

        return err;
}

void p9pdu_reset(struct p9_fcall *pdu)
{
        pdu->offset = 0;
        pdu->size = 0;
}

int p9dirent_read(struct p9_client *clnt, char *buf, int len,
                  struct p9_dirent *dirent)
{
        struct p9_fcall fake_pdu;
        int ret;
        char *nameptr;

        fake_pdu.size = len;
        fake_pdu.capacity = len;
        fake_pdu.sdata = buf;
        fake_pdu.offset = 0;

        ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
                          &dirent->d_off, &dirent->d_type, &nameptr);
        if (ret) {
                p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
                trace_9p_protocol_dump(clnt, &fake_pdu);
                return ret;
        }

        ret = strscpy(dirent->d_name, nameptr, sizeof(dirent->d_name));
        if (ret < 0) {
                p9_debug(P9_DEBUG_ERROR,
                         "On the wire dirent name too long: %s\n",
                         nameptr);
                kfree(nameptr);
                return ret;
        }
        kfree(nameptr);

        return fake_pdu.offset;
}
EXPORT_SYMBOL(p9dirent_read);