[Qemu-devel] [PATCH -V3 07/32] virtio-9p: Implement P9_TREAD

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

From: Anthony Liguori <aliguori@us.ibm.com>

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/virtio-9p-local.c |   37 ++++++++
 hw/virtio-9p.c       |  253 +++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 287 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
index d8cb70d..d77ecc2 100644
--- a/hw/virtio-9p-local.c
+++ b/hw/virtio-9p-local.c
@@ -98,6 +98,37 @@ static DIR *local_opendir(void *opaque, const char *path)
     return opendir(rpath(path));
 }
 
+static void local_rewinddir(void *opaque, DIR *dir)
+{
+    return rewinddir(dir);
+}
+
+static off_t local_telldir(void *opaque, DIR *dir)
+{
+    return telldir(dir);
+}
+
+static struct dirent *local_readdir(void *opaque, DIR *dir)
+{
+    return readdir(dir);
+}
+
+static void local_seekdir(void *opaque, DIR *dir, off_t off)
+{
+    return seekdir(dir, off);
+}
+
+static ssize_t local_readv(void *opaque, int fd, const struct iovec *iov,
+			   int iovcnt)
+{
+    return readv(fd, iov, iovcnt);
+}
+
+static off_t local_lseek(void *opaque, int fd, off_t offset, int whence)
+{
+    return lseek(fd, offset, whence);
+}
+
 static V9fsPosixFileOperations ops = {
     .lstat = local_lstat,
     .setuid = local_setuid,
@@ -106,6 +137,12 @@ static V9fsPosixFileOperations ops = {
     .closedir = local_closedir,
     .open = local_open,
     .opendir = local_opendir,
+    .rewinddir = local_rewinddir,
+    .telldir = local_telldir,
+    .readdir = local_readdir,
+    .seekdir = local_seekdir,
+    .readv = local_readv,
+    .lseek = local_lseek,
 };
 
 V9fsPosixFileOperations *virtio_9p_init_local(const char *path)
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index f1df0b9..9bc0a57 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -137,6 +137,37 @@ static DIR *posix_opendir(V9fsState *s, V9fsString *path)
     return s->ops->opendir(s->ops->opaque, path->data);
 }
 
+static void posix_rewinddir(V9fsState *s, DIR *dir)
+{
+    return s->ops->rewinddir(s->ops->opaque, dir);
+}
+
+static off_t posix_telldir(V9fsState *s, DIR *dir)
+{
+    return s->ops->telldir(s->ops->opaque, dir);
+}
+
+static struct dirent *posix_readdir(V9fsState *s, DIR *dir)
+{
+    return s->ops->readdir(s->ops->opaque, dir);
+}
+
+static void posix_seekdir(V9fsState *s, DIR *dir, off_t off)
+{
+    return s->ops->seekdir(s->ops->opaque, dir, off);
+}
+
+static int posix_readv(V9fsState *s, int fd, const struct iovec *iov,
+		       int iovcnt)
+{
+    return s->ops->readv(s->ops->opaque, fd, iov, iovcnt);
+}
+
+static off_t posix_lseek(V9fsState *s, int fd, off_t offset, int whence)
+{
+    return s->ops->lseek(s->ops->opaque, fd, offset, whence);
+}
+
 static void v9fs_string_init(V9fsString *str)
 {
     str->data = NULL;
@@ -1048,14 +1079,230 @@ out:
     qemu_free(vs);
 }
 
-static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
+static struct iovec *adjust_sg(struct iovec *sg, int len, int *iovcnt)
 {
-    if (debug_9p_pdu)
-	pprint_pdu(pdu);
+    while (len && *iovcnt) {
+        if (len < sg->iov_len) {
+            sg->iov_len -= len;
+            sg->iov_base += len;
+            len = 0;
+        } else {
+            len -= sg->iov_len;
+            sg++;
+            *iovcnt -= 1;
+        }
+    }
+
+    return sg;
+}
+
+static struct iovec *cap_sg(struct iovec *sg, int cap, int *cnt)
+{
+    int i;
+    int total = 0;
+
+    for (i = 0; i < *cnt; i++) {
+        if ((total + sg[i].iov_len) > cap) {
+            sg[i].iov_len -= ((total + sg[i].iov_len) - cap);
+            i++;
+            break;
+        }
+        total += sg[i].iov_len;
+    }
+
+    *cnt = i;
+
+    return sg;
+}
+
+static void print_sg(struct iovec *sg, int cnt)
+{
+    int i;
+
+    printf("sg[%d]: {", cnt);
+    for (i = 0; i < cnt; i++) {
+        if (i)
+            printf(", ");
+        printf("(%p, %zd)", sg[i].iov_base, sg[i].iov_len);
+    }
+    printf("}\n");
+}
+
+typedef struct V9fsReadState {
+    V9fsPDU *pdu;
+    size_t offset;
+    int32_t fid;
+    int32_t count;
+    int32_t total;
+    int64_t off;
+    V9fsFidState *fidp;
+    struct iovec iov[128]; /* FIXME: bad, bad, bad */
+    struct iovec *sg;
+    off_t dir_pos;
+    struct dirent *dent;
+    struct stat stbuf;
+    V9fsString name;
+    V9fsStat v9stat;
+    int32_t len;
+    int32_t cnt;
+    int32_t max_count;
+} V9fsReadState;
+
+static void v9fs_read_post_readdir(V9fsState *, V9fsReadState *, ssize_t );
+
+static void v9fs_read_post_seekdir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+{
+    v9fs_stat_free(&vs->v9stat);
+    v9fs_string_free(&vs->name);
+    vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->count);
+    vs->offset += vs->count;
+    err = vs->offset;
+    complete_pdu(s, vs->pdu, err);
+    qemu_free(vs);
+    return;
+}
+
+static void v9fs_read_post_dir_lstat(V9fsState *s, V9fsReadState *vs,
+                                    ssize_t err)
+{
+    BUG_ON(err == -1);
+    stat_to_v9stat(s, &vs->name, &vs->stbuf, &vs->v9stat);
+
+    vs->len = pdu_marshal(vs->pdu, vs->offset + 4 + vs->count, "S",
+                            &vs->v9stat);
+    if ((vs->len != (vs->v9stat.size + 2)) ||
+            ((vs->count + vs->len) > vs->max_count)) {
+        posix_seekdir(s, vs->fidp->dir, vs->dir_pos);
+        v9fs_read_post_seekdir(s, vs, err);
+        return;
+    }
+    vs->count += vs->len;
+    v9fs_stat_free(&vs->v9stat);
+    v9fs_string_free(&vs->name);
+    vs->dir_pos = vs->dent->d_off;
+    vs->dent = posix_readdir(s, vs->fidp->dir);
+    v9fs_read_post_readdir(s, vs, err);
+    return;
+}
+
+static void v9fs_read_post_readdir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+{
+    if (vs->dent) {
+        memset(&vs->v9stat, 0, sizeof(vs->v9stat));
+        v9fs_string_init(&vs->name);
+        v9fs_string_sprintf(&vs->name, "%s/%s", vs->fidp->path.data,
+                            vs->dent->d_name);
+        err = posix_lstat(s, &vs->name, &vs->stbuf);
+        v9fs_read_post_dir_lstat(s, vs, err);
+        return;
+    }
+
+    vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->count);
+    vs->offset += vs->count;
+    err = vs->offset;
+    complete_pdu(s, vs->pdu, err);
+    qemu_free(vs);
+    return;
+}
+
+static void v9fs_read_post_telldir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+{
+    vs->dent = posix_readdir(s, vs->fidp->dir);
+    v9fs_read_post_readdir(s, vs, err);
+    return;
+}
+
+static void v9fs_read_post_rewinddir(V9fsState *s, V9fsReadState *vs,
+                                       ssize_t err)
+{
+    vs->dir_pos = posix_telldir(s, vs->fidp->dir);
+    v9fs_read_post_telldir(s, vs, err);
+    return;
+}
+
+static void v9fs_read_post_readv(V9fsState *s, V9fsReadState *vs, ssize_t err)
+{
+    BUG_ON(vs->len < 0);
+    vs->total += vs->len;
+    vs->sg = adjust_sg(vs->sg, vs->len, &vs->cnt);
+    if (vs->total < vs->count && vs->len > 0) {
+        do {
+            if (0) {
+                print_sg(vs->sg, vs->cnt);
+            }
+            vs->len = posix_readv(s, vs->fidp->fd, vs->sg, vs->cnt);
+        } while (vs->len == -1 && errno == EINTR);
+        v9fs_read_post_readv(s, vs, err);
+        return;
+    }
+    vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->total);
+    vs->offset += vs->count;
+    err = vs->offset;
+    complete_pdu(s, vs->pdu, err);
+    qemu_free(vs);
+}
+
+static void v9fs_read_post_lseek(V9fsState *s, V9fsReadState *vs, ssize_t err)
+{
+    BUG_ON(err == -1);
+    vs->sg = cap_sg(vs->sg, vs->count, &vs->cnt);
+
+    if (vs->total < vs->count) {
+        do {
+            if (0) {
+                print_sg(vs->sg, vs->cnt);
+            }
+            vs->len = posix_readv(s, vs->fidp->fd, vs->sg, vs->cnt);
+        } while (vs->len == -1 && errno == EINTR);
+        v9fs_read_post_readv(s, vs, err);
+        return;
+    }
 }
 
 static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
 {
+    V9fsReadState *vs;
+    ssize_t err = 0;
+
+    vs = qemu_malloc(sizeof(*vs));
+    vs->pdu = pdu;
+    vs->offset = 7;
+    vs->total = 0;
+    vs->len = 0;
+    vs->count = 0;
+
+    pdu_unmarshal(vs->pdu, vs->offset, "dqd", &vs->fid, &vs->off, &vs->count);
+
+    vs->fidp = lookup_fid(s, vs->fid);
+    if (vs->fidp == NULL) {
+        err = -EINVAL;
+        goto out;
+    }
+
+    if (vs->fidp->dir) {
+        vs->max_count = vs->count;
+        vs->count = 0;
+        if (vs->off == 0) {
+            posix_rewinddir(s, vs->fidp->dir);
+        }
+        v9fs_read_post_rewinddir(s, vs, err);
+        return;
+    } else if (vs->fidp->fd != -1) {
+        vs->sg = vs->iov;
+        pdu_marshal(vs->pdu, vs->offset + 4, "v", vs->sg, &vs->cnt);
+        err = posix_lseek(s, vs->fidp->fd, vs->off, SEEK_SET);
+        v9fs_read_post_lseek(s, vs, err);
+        return;
+    } else {
+        err = -EINVAL;
+    }
+out:
+    complete_pdu(s, pdu, err);
+    qemu_free(vs);
+}
+
+static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
+{
     if (debug_9p_pdu)
         pprint_pdu(pdu);
 }
-- 
1.7.0.2.323.g0d092