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-rw-r--r--net/9p/protocol.c801
1 files changed, 801 insertions, 0 deletions
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
new file mode 100644
index 0000000000..0e6603b1ec
--- /dev/null
+++ b/net/9p/protocol.c
@@ -0,0 +1,801 @@
+// 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_array(*nwqid,
+ sizeof(struct p9_qid),
+ 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);